Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

NASA Astrophysics Data System (ADS)

Shi, Chengyu; Guo, Bingqi; Cheng, Chih-Yao; Eng, Tony; Papanikolaou, Nikos

2010-09-01

A low-energy electronic brachytherapy source (EBS), the model S700 Axxent™ x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V100 reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as compared to 95.2% in water phantoms without RBE enhancement (planned BED). About 10% increase in the source output is required to raise BED PTV V100 to 95%. As a conclusion, the composite effect of dose reduction in the target due to heterogeneities and RBE enhancement results in a net effect of 5.3% target BED coverage loss for electronic brachytherapy. Therefore, it is suggested that about 10% increase in the source output may be necessary to achieve sufficient target coverage higher than 95%.

TU-H-CAMPUS-JeP3-05: Adaptive Determination of Needle Sequence HDR Prostate Brachytherapy with Divergent Needle-By-Needle Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borot de Battisti, M; Maenhout, M; Lagendijk, J J W

Purpose: To develop a new method which adaptively determines the optimal needle insertion sequence for HDR prostate brachytherapy involving divergent needle-by-needle dose delivery by e.g. a robotic device. A needle insertion sequence is calculated at the beginning of the intervention and updated after each needle insertion with feedback on needle positioning errors. Methods: Needle positioning errors and anatomy changes may occur during HDR brachytherapy which can lead to errors in the delivered dose. A novel strategy was developed to calculate and update the needle sequence and the dose plan after each needle insertion with feedback on needle positioning errors. Themore » dose plan optimization was performed by numerical simulations. The proposed needle sequence determination optimizes the final dose distribution based on the dose coverage impact of each needle. This impact is predicted stochastically by needle insertion simulations. HDR procedures were simulated with varying number of needle insertions (4 to 12) using 11 patient MR data-sets with PTV, prostate, urethra, bladder and rectum delineated. Needle positioning errors were modeled by random normally distributed angulation errors (standard deviation of 3 mm at the needle’s tip). The final dose parameters were compared in the situations where the needle with the largest vs. the smallest dose coverage impact was selected at each insertion. Results: Over all scenarios, the percentage of clinically acceptable final dose distribution improved when the needle selected had the largest dose coverage impact (91%) compared to the smallest (88%). The differences were larger for few (4 to 6) needle insertions (maximum difference scenario: 79% vs. 60%). The computation time of the needle sequence optimization was below 60s. Conclusion: A new adaptive needle sequence determination for HDR prostate brachytherapy was developed. Coupled to adaptive planning, the selection of the needle with the largest dose coverage impact increases chances of reaching the clinical constraints. M. Borot de Battisti is funded by Philips Medical Systems Nederland B.V.; M. Moerland is principal investigator on a contract funded by Philips Medical Systems Nederland B.V.; G. Hautvast and D. Binnekamp are fulltime employees of Philips Medical Systems Nederland B.V.« less

Effect of tissue composition on dose distribution in brachytherapy with various photon emitting sources

PubMed Central

Ghorbani, Mahdi; Salahshour, Fateme; Haghparast, Abbas; Knaup, Courtney

2014-01-01

Purpose The aim of this study is to compare the dose in various soft tissues in brachytherapy with photon emitting sources. Material and methods 103Pd, 125I, 169Yb, 192Ir brachytherapy sources were simulated with MCNPX Monte Carlo code, and their dose rate constant and radial dose function were compared with the published data. A spherical phantom with 50 cm radius was simulated and the dose at various radial distances in adipose tissue, breast tissue, 4-component soft tissue, brain (grey/white matter), muscle (skeletal), lung tissue, blood (whole), 9-component soft tissue, and water were calculated. The absolute dose and relative dose difference with respect to 9-component soft tissue was obtained for various materials, sources, and distances. Results There was good agreement between the dosimetric parameters of the sources and the published data. Adipose tissue, breast tissue, 4-component soft tissue, and water showed the greatest difference in dose relative to the dose to the 9-component soft tissue. The other soft tissues showed lower dose differences. The dose difference was also higher for 103Pd source than for 125I, 169Yb, and 192Ir sources. Furthermore, greater distances from the source had higher relative dose differences and the effect can be justified due to the change in photon spectrum (softening or hardening) as photons traverse the phantom material. Conclusions The ignorance of soft tissue characteristics (density, composition, etc.) by treatment planning systems incorporates a significant error in dose delivery to the patient in brachytherapy with photon sources. The error depends on the type of soft tissue, brachytherapy source, as well as the distance from the source. PMID:24790623

SU-F-T-17: A Feasibility Study for the Transit Dosimetry with a Glass Dosimeter in Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moon, S; Yoon, M; Chung, W

Purpose: Confirming the dose delivered to a patient is important to make sure the treatment quality and safety of the radiotherapy. Measuring a transit dose of the patient during the radiotherapy could be an interesting way to confirm the patient dose. In this study, we evaluated the feasibility of the transit dosimetry with a glass dosimeter in brachytherapy. Methods: We made a phantom that inserted the glass dosimeters and placed under patient lying on a couch for cervix cancer brachytherapy. The 18 glass dosimeters were placed in the phantom arranged 6 per row. A point putting 1cm vertically from themore » source was prescribed as 500.00 cGy. Solid phantoms of 0, 2, 4, 6, 8, 10 cm were placed between the source and the glass dosimeter. The transit dose was measured each thickness using the glass dosimeters and compared with a treatment planning system (TPS). Results: When the transit dose was smaller than 10 cGy, the average of the differences between measured values and calculated values by TPS was 0.50 cGy and the standard deviation was 0.69 cGy. If the transit dose was smaller than 100 cGy, the average of the error was 1.67 ± 4.01 cGy. The error to a point near the prescription point was −14.02 cGy per 500.00 cGy of the prescription dose. Conclusion: The distances from the sources to skin of the patient generally are within 10 cm for cervix cancer cases in brachytherapy. The results of this preliminary study showed the probability of the glass dosimeter as the transit dosimeter in brachytherapy.« less

SU-F-T-65: AutomaticTreatment Planning for High-Dose Rate (HDR) Brachytherapy with a VaginalCylinder Applicator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Y; Tan, J; Jiang, S

Purpose: High dose rate (HDR) brachytherapy treatment planning is conventionally performed in a manual fashion. Yet it is highly desirable to perform computerized automated planning to improve treatment planning efficiency, eliminate human errors, and reduce plan quality variation. The goal of this research is to develop an automatic treatment planning tool for HDR brachytherapy with a cylinder applicator for vaginal cancer. Methods: After inserting the cylinder applicator into the patient, a CT scan was acquired and was loaded to an in-house developed treatment planning software. The cylinder applicator was automatically segmented using image-processing techniques. CTV was generated based on user-specifiedmore » treatment depth and length. Locations of relevant points (apex point, prescription point, and vaginal surface point), central applicator channel coordinates, and dwell positions were determined according to their geometric relations with the applicator. Dwell time was computed through an inverse optimization process. The planning information was written into DICOM-RT plan and structure files to transfer the automatically generated plan to a commercial treatment planning system for plan verification and delivery. Results: We have tested the system retrospectively in nine patients treated with vaginal cylinder applicator. These cases were selected with different treatment prescriptions, lengths, depths, and cylinder diameters to represent a large patient population. Our system was able to generate treatment plans for these cases with clinically acceptable quality. Computation time varied from 3–6 min. Conclusion: We have developed a system to perform automated treatment planning for HDR brachytherapy with a cylinder applicator. Such a novel system has greatly improved treatment planning efficiency and reduced plan quality variation. It also served as a testbed to demonstrate the feasibility of automatic HDR treatment planning for more complicated cases.« less

TU-D-201-06: HDR Plan Prechecks Using Eclipse Scripting API

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palaniswaamy, G; Morrow, A; Kim, S

Purpose: Automate brachytherapy treatment plan quality check using Eclipse v13.6 scripting API based on pre-configured rules to minimize human error and maximize efficiency. Methods: The HDR Precheck system is developed based on a rules-driven approach using Eclipse scripting API. This system checks for critical plan parameters like channel length, first source position, source step size and channel mapping. The planned treatment time is verified independently based on analytical methods. For interstitial or SAVI APBI treatment plans, a Patterson-Parker system calculation is performed to verify the planned treatment time. For endobronchial treatments, an analytical formula from TG-59 is used. Acceptable tolerancesmore » were defined based on clinical experiences in our department. The system was designed to show PASS/FAIL status levels. Additional information, if necessary, is indicated appropriately in a separate comments field in the user interface. Results: The HDR Precheck system has been developed and tested to verify the treatment plan parameters that are routinely checked by the clinical physicist. The report also serves as a reminder or checklist for the planner to perform any additional critical checks such as applicator digitization or scenarios where the channel mapping was intentionally changed. It is expected to reduce the current manual plan check time from 15 minutes to <1 minute. Conclusion: Automating brachytherapy plan prechecks significantly reduces treatment plan precheck time and reduces human errors. When fully developed, this system will be able to perform TG-43 based second check of the treatment planning system’s dose calculation using random points in the target and critical structures. A histogram will be generated along with tabulated mean and standard deviation values for each structure. A knowledge database will also be developed for Brachyvision plans which will then be used for knowledge-based plan quality checks to further reduce treatment planning errors and increase confidence in the planned treatment.« less

Systematic analysis of the scatter environment in clinical intra-operative high dose rate (IOHDR) brachytherapy

NASA Astrophysics Data System (ADS)

Oh, Moonseong

Most brachytherapy planning systems are based on a dose calculation algorithm that assumes an infinite scatter environment surrounding the target volume and applicator. In intra-operative high dose rate brachytherapy (IOHDR) where treatment catheters are typically laid either directly on a tumor bed or within applicators that may have little or no scatter material above them, the lack of scatter from one side of the applicator can result in serious underdosage during treatment. Therefore, full analyses of the physical processes such as the photoelectric effect, Rayleigh, and Compton scattering that contribute to dosimetric errors have to be investigated and documented to result in more accurate treatment delivery to patients undergoing IOHDR procedures. Monte Carlo simulation results showed the Compton scattering effect is about 40 times more probable than photoelectric effect for the treated areas of single source, 4 x 4, and 2 x 4 cm2. Also, the dose variations with and without photoelectric effect were 0.3 ˜ 0.7%, which are within the uncertainty in Monte Carlo simulations. Also, Monte Carlo simulation studies were done to verify the following experimental results for quantification of dosimetric errors in clinical IOHDR brachytherapy. The first experimental study was performed to quantify the inaccuracy in clinical dose delivery due to the incomplete scatter conditions inherent in IOHDR brachytherapy. Treatment plans were developed for 3 different treatment surface areas (4 x 4, 7 x 7, 12 x 12 cm2), each with prescription points located at 3 distances (0.5 cm, 1.0 cm, and 1.5 cm) from the source dwell positions. Measurements showed that the magnitude of the underdosage varies from about 8% to 13% of the prescription dose as the prescription depth is increased from 0.5 cm to 1.5 cm. This treatment error was found to be independent of the irradiated area and strongly dependent on the prescription distance. The study was extended to confirm the underdosage for various shape of treated area (especially, irregular shape), which can be applied in clinical cases. Treatment plans of 10 patients previously treated at Roswell Park Cancer Institute in Buffalo, which had irregular shapes of treated areas, were used. In IOHDR brachytherapy, a 2-dimensional (2-D) planar geometry is typically used without considering the curved shape of target surfaces. In clinical cases, this assumption of the planar geometry may cause the serious dose delivery errors to target volumes. The second study was performed to investigate the dose errors to curved surfaces. Seven rectangular shaped plans (five for 1.0 cm and two for 0.5 cm prescription depth) and archived irregular shaped plans of 2 patients were analyzed. Cylindrical phantoms with six radii (ranged 1.35 to 12.5 cm) were used to simulate the treatment planning geometries, which were calculated in 2-D plans. Actual doses delivered to prescription points were over-estimated up to 15% on the concave side of curved applicators for all cylindrical phantoms with 1.0 cm prescription depth. Also, delivered doses decreased by up to 10% on the convex side of curved applicators for small treated areas (≤ 5catheters), but interestingly, any dose dependence was not shown with large treated areas. Our measurements have shown inaccuracy in dose delivery when the original planar treatment plan was delivered in a curved applicator setting. Dose errors arising due to the tumor curvature may be significant in a clinical set up and merit attention during planning.

Quality control in interstitial brachytherapy of the breast using pulsed dose rate: treatment planning and dose delivery with an Ir-192 afterloading system.

PubMed

Mangold, C A; Rijnders, A; Georg, D; Van Limbergen, E; Pötter, R; Huyskens, D

2001-01-01

In the Radiotherapy Department of Leuven, about 20% of all breast cancer patients treated with breast conserving surgery and external radiotherapy receive an additional boost with pulsed dose rate (PDR) Ir-192 brachytherapy. An investigation was performed to assess the accuracy of the delivered PDR brachytherapy treatment. Secondly, the feasibility of in vivo measurements during PDR dose delivery was investigated. Two phantoms are manufactured to mimic a breast, one for thermoluminescent dosimetry (TLD) measurements, and one for dosimetry using radiochromic films. The TLD phantom allows measurements at 34 dose points in three planes including the basal dose points. The film phantom is designed in such a way that films can be positioned in a plane parallel and orthogonal to the needles. The dose distributions calculated with the TPS are in good agreement with both TLD and radiochromic film measurements (average deviations of point doses <+/-5%). However, close to the interface tissue-air the dose is overestimated by the TPS since it neglects the finite size of a breast and the associated lack of backscatter (average deviations of point doses -14%). Most deviations between measured and calculated doses, are in the order of magnitude of the uncertainty associated with the source strength specification, except for the point doses measured close to the skin. In vivo dosimetry during PDR brachytherapy treatment was found to be a valuable procedure to detect large errors, e.g. errors caused by an incorrect data transfer.

Current status of brachytherapy in Korea: a national survey of radiation oncologists

PubMed Central

Kim, Joo-Young; Park, Won; Kim, Young Seok

2016-01-01

Objective The aim of the present study was to acquire information on brachytherapy resources in Korea through a national survey of radiation oncologists. Methods Between October 2014 and January 2015, a questionnaire on the current status of brachytherapy was distributed to all 86 radiation oncology departments in Korea. The questionnaire was divided into sections querying general information on human resources, brachytherapy equipment, and suggestions for future directions of brachytherapy policy in Korea. Results The response rate of the survey was 88.3%. The average number of radiation oncologists per center was 2.3. At the time of survey, 28 centers (36.8%) provided brachytherapy to patients. Among the 28 brachytherapy centers, 15 (53.5%) were located in in the capital Seoul and its surrounding metropolitan areas. All brachytherapy centers had a high-dose rate system using 192Ir (26 centers) or 60Co (two centers). Among the 26 centers using 192Ir sources, 11 treated fewer than 40 patients per year. In the two centers using 60Co sources, the number of patients per year was 16 and 120, respectively. The most frequently cited difficulties in performing brachytherapy were cost related. A total of 21 centers had a plan to sustain the current brachytherapy system, and four centers noted plans to upgrade their brachytherapy system. Two centers stated that they were considering discontinuation of brachytherapy due to cost burdens of radioisotope source replacement. Conclusion The present study illustrated the current status of brachytherapy in Korea. Financial difficulties were the major barriers to the practice of brachytherapy. PMID:27102244

Current status of brachytherapy in Korea: a national survey of radiation oncologists.

PubMed

Kim, Haeyoung; Kim, Joo Young; Kim, Juree; Park, Won; Kim, Young Seok; Kim, Hak Jae; Kim, Yong Bae

2016-07-01

The aim of the present study was to acquire information on brachytherapy resources in Korea through a national survey of radiation oncologists. Between October 2014 and January 2015, a questionnaire on the current status of brachytherapy was distributed to all 86 radiation oncology departments in Korea. The questionnaire was divided into sections querying general information on human resources, brachytherapy equipment, and suggestions for future directions of brachytherapy policy in Korea. The response rate of the survey was 88.3%. The average number of radiation oncologists per center was 2.3. At the time of survey, 28 centers (36.8%) provided brachytherapy to patients. Among the 28 brachytherapy centers, 15 (53.5%) were located in in the capital Seoul and its surrounding metropolitan areas. All brachytherapy centers had a high-dose rate system using (192)Ir (26 centers) or (60)Co (two centers). Among the 26 centers using (192)Ir sources, 11 treated fewer than 40 patients per year. In the two centers using (60)Co sources, the number of patients per year was 16 and 120, respectively. The most frequently cited difficulties in performing brachytherapy were cost related. A total of 21 centers had a plan to sustain the current brachytherapy system, and four centers noted plans to upgrade their brachytherapy system. Two centers stated that they were considering discontinuation of brachytherapy due to cost burdens of radioisotope source replacement. The present study illustrated the current status of brachytherapy in Korea. Financial difficulties were the major barriers to the practice of brachytherapy.

ALGEBRA: ALgorithm for the heterogeneous dosimetry based on GEANT4 for BRAchytherapy.

PubMed

Afsharpour, H; Landry, G; D'Amours, M; Enger, S; Reniers, B; Poon, E; Carrier, J-F; Verhaegen, F; Beaulieu, L

2012-06-07

Task group 43 (TG43)-based dosimetry algorithms are efficient for brachytherapy dose calculation in water. However, human tissues have chemical compositions and densities different than water. Moreover, the mutual shielding effect of seeds on each other (interseed attenuation) is neglected in the TG43-based dosimetry platforms. The scientific community has expressed the need for an accurate dosimetry platform in brachytherapy. The purpose of this paper is to present ALGEBRA, a Monte Carlo platform for dosimetry in brachytherapy which is sufficiently fast and accurate for clinical and research purposes. ALGEBRA is based on the GEANT4 Monte Carlo code and is capable of handling the DICOM RT standard to recreate a virtual model of the treated site. Here, the performance of ALGEBRA is presented for the special case of LDR brachytherapy in permanent prostate and breast seed implants. However, the algorithm is also capable of handling other treatments such as HDR brachytherapy.

Accuracy Evaluation of Oncentra™ TPS in HDR Brachytherapy of Nasopharynx Cancer Using EGSnrc Monte Carlo Code.

PubMed

Hadad, K; Zohrevand, M; Faghihi, R; Sedighi Pashaki, A

2015-03-01

HDR brachytherapy is one of the commonest methods of nasopharyngeal cancer treatment. In this method, depending on how advanced one tumor is, 2 to 6 Gy dose as intracavitary brachytherapy is prescribed. Due to high dose rate and tumor location, accuracy evaluation of treatment planning system (TPS) is particularly important. Common methods used in TPS dosimetry are based on computations in a homogeneous phantom. Heterogeneous phantoms, especially patient-specific voxel phantoms can increase dosimetric accuracy. In this study, using CT images taken from a patient and ctcreate-which is a part of the DOSXYZnrc computational code, patient-specific phantom was made. Dose distribution was plotted by DOSXYZnrc and compared with TPS one. Also, by extracting the voxels absorbed dose in treatment volume, dose-volume histograms (DVH) was plotted and compared with Oncentra™ TPS DVHs. The results from calculations were compared with data from Oncentra™ treatment planning system and it was observed that TPS calculation predicts lower dose in areas near the source, and higher dose in areas far from the source relative to MC code. Absorbed dose values in the voxels also showed that TPS reports D90 value is 40% higher than the Monte Carlo method. Today, most treatment planning systems use TG-43 protocol. This protocol may results in errors such as neglecting tissue heterogeneity, scattered radiation as well as applicator attenuation. Due to these errors, AAPM emphasized departing from TG-43 protocol and approaching new brachytherapy protocol TG-186 in which patient-specific phantom is used and heterogeneities are affected in dosimetry.

Characterization of a fiber-coupled Al2O3:C luminescence dosimetry system for online in vivo dose verification during 192Ir brachytherapy.

PubMed

Andersen, Claus E; Nielsen, Søren Kynde; Greilich, Steffen; Helt-Hansen, Jakob; Lindegaard, Jacob Christian; Tanderup, Kari

2009-03-01

A prototype of a new dose-verification system has been developed to facilitate prevention and identification of dose delivery errors in remotely afterloaded brachytherapy. The system allows for automatic online in vivo dosimetry directly in the tumor region using small passive detector probes that fit into applicators such as standard needles or catheters. The system measures the absorbed dose rate (0.1 s time resolution) and total absorbed dose on the basis of radioluminescence (RL) and optically stimulated luminescence (OSL) from aluminum oxide crystals attached to optical fiber cables (1 mm outer diameter). The system was tested in the range from 0 to 4 Gy using a solid-water phantom, a Varian GammaMed Plus 192Ir PDR afterloader, and dosimetry probes inserted into stainless-steel brachytherapy needles. The calibrated system was found to be linear in the tested dose range. The reproducibility (one standard deviation) for RL and OSL measurements was 1.3%. The measured depth-dose profiles agreed well with the theoretical expectations computed with the EGSNRC Monte Carlo code, suggesting that the energy dependence for the dosimeter probes (relative to water) is less than 6% for source-to-probe distances in the range of 2-50 mm. Under certain conditions, the RL signal could be greatly disturbed by the so-called stem signal (i.e., unwanted light generated in the fiber cable upon irradiation). The OSL signal is not subject to this source of error. The tested system appears to be adequate for in vivo brachytherapy dosimetry.

Accuracy Evaluation of Oncentra™ TPS in HDR Brachytherapy of Nasopharynx Cancer Using EGSnrc Monte Carlo Code

PubMed Central

Hadad, K.; Zohrevand, M.; Faghihi, R.; Sedighi Pashaki, A.

2015-01-01

Background HDR brachytherapy is one of the commonest methods of nasopharyngeal cancer treatment. In this method, depending on how advanced one tumor is, 2 to 6 Gy dose as intracavitary brachytherapy is prescribed. Due to high dose rate and tumor location, accuracy evaluation of treatment planning system (TPS) is particularly important. Common methods used in TPS dosimetry are based on computations in a homogeneous phantom. Heterogeneous phantoms, especially patient-specific voxel phantoms can increase dosimetric accuracy. Materials and Methods In this study, using CT images taken from a patient and ctcreate-which is a part of the DOSXYZnrc computational code, patient-specific phantom was made. Dose distribution was plotted by DOSXYZnrc and compared with TPS one. Also, by extracting the voxels absorbed dose in treatment volume, dose-volume histograms (DVH) was plotted and compared with Oncentra™ TPS DVHs. Results The results from calculations were compared with data from Oncentra™ treatment planning system and it was observed that TPS calculation predicts lower dose in areas near the source, and higher dose in areas far from the source relative to MC code. Absorbed dose values in the voxels also showed that TPS reports D90 value is 40% higher than the Monte Carlo method. Conclusion Today, most treatment planning systems use TG-43 protocol. This protocol may results in errors such as neglecting tissue heterogeneity, scattered radiation as well as applicator attenuation. Due to these errors, AAPM emphasized departing from TG-43 protocol and approaching new brachytherapy protocol TG-186 in which patient-specific phantom is used and heterogeneities are affected in dosimetry. PMID:25973408

Online pretreatment verification of high-dose rate brachytherapy using an imaging panel

NASA Astrophysics Data System (ADS)

Fonseca, Gabriel P.; Podesta, Mark; Bellezzo, Murillo; Van den Bosch, Michiel R.; Lutgens, Ludy; Vanneste, Ben G. L.; Voncken, Robert; Van Limbergen, Evert J.; Reniers, Brigitte; Verhaegen, Frank

2017-07-01

Brachytherapy is employed to treat a wide variety of cancers. However, an accurate treatment verification method is currently not available. This study describes a pre-treatment verification system that uses an imaging panel (IP) to verify important aspects of the treatment plan. A detailed modelling of the IP was only possible with an extensive calibration performed using a robotic arm. Irradiations were performed with a high dose rate (HDR) 192Ir source within a water phantom. An empirical fit was applied to measure the distance between the source and the detector so 3D Cartesian coordinates of the dwell positions can be obtained using a single panel. The IP acquires 7.14 fps to verify the dwell times, dwell positions and air kerma strength (Sk). A gynecological applicator was used to create a treatment plan that was registered with a CT image of the water phantom used during the experiments for verification purposes. Errors (shifts, exchanged connections and wrong dwell times) were simulated to verify the proposed verification system. Cartesian source positions (panel measurement plane) have a standard deviation of about 0.02 cm. The measured distance between the source and the panel (z-coordinate) have a standard deviation up to 0.16 cm and maximum absolute error of  ≈0.6 cm if the signal is close to sensitive limit of the panel. The average response of the panel is very linear with Sk. Therefore, Sk measurements can be performed with relatively small errors. The measured dwell times show a maximum error of 0.2 s which is consistent with the acquisition rate of the panel. All simulated errors were clearly identified by the proposed system. The use of IPs is not common in brachytherapy, however, it provides considerable advantages. It was demonstrated that the IP can accurately measure Sk, dwell times and dwell positions.

Online pretreatment verification of high-dose rate brachytherapy using an imaging panel.

PubMed

Fonseca, Gabriel P; Podesta, Mark; Bellezzo, Murillo; Van den Bosch, Michiel R; Lutgens, Ludy; Vanneste, Ben G L; Voncken, Robert; Van Limbergen, Evert J; Reniers, Brigitte; Verhaegen, Frank

2017-07-07

Brachytherapy is employed to treat a wide variety of cancers. However, an accurate treatment verification method is currently not available. This study describes a pre-treatment verification system that uses an imaging panel (IP) to verify important aspects of the treatment plan. A detailed modelling of the IP was only possible with an extensive calibration performed using a robotic arm. Irradiations were performed with a high dose rate (HDR) 192 Ir source within a water phantom. An empirical fit was applied to measure the distance between the source and the detector so 3D Cartesian coordinates of the dwell positions can be obtained using a single panel. The IP acquires 7.14 fps to verify the dwell times, dwell positions and air kerma strength (Sk). A gynecological applicator was used to create a treatment plan that was registered with a CT image of the water phantom used during the experiments for verification purposes. Errors (shifts, exchanged connections and wrong dwell times) were simulated to verify the proposed verification system. Cartesian source positions (panel measurement plane) have a standard deviation of about 0.02 cm. The measured distance between the source and the panel (z-coordinate) have a standard deviation up to 0.16 cm and maximum absolute error of  ≈0.6 cm if the signal is close to sensitive limit of the panel. The average response of the panel is very linear with Sk. Therefore, Sk measurements can be performed with relatively small errors. The measured dwell times show a maximum error of 0.2 s which is consistent with the acquisition rate of the panel. All simulated errors were clearly identified by the proposed system. The use of IPs is not common in brachytherapy, however, it provides considerable advantages. It was demonstrated that the IP can accurately measure Sk, dwell times and dwell positions.

SU-C-BRD-02: A Team Focused Clinical Implementation and Failure Mode and Effects Analysis of HDR Skin Brachytherapy Using Valencia and Leipzig Surface Applicators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sayler, E; Harrison, A; Eldredge-Hindy, H

Purpose: and Leipzig applicators (VLAs) are single-channel brachytherapy surface applicators used to treat skin lesions up to 2cm diameter. Source dwell times can be calculated and entered manually after clinical set-up or ultrasound. This procedure differs dramatically from CT-based planning; the novelty and unfamiliarity could lead to severe errors. To build layers of safety and ensure quality, a multidisciplinary team created a protocol and applied Failure Modes and Effects Analysis (FMEA) to the clinical procedure for HDR VLA skin treatments. Methods: team including physicists, physicians, nurses, therapists, residents, and administration developed a clinical procedure for VLA treatment. The procedure wasmore » evaluated using FMEA. Failure modes were identified and scored by severity, occurrence, and detection. The clinical procedure was revised to address high-scoring process nodes. Results: Several key components were added to the clinical procedure to minimize risk probability numbers (RPN): -Treatments are reviewed at weekly QA rounds, where physicians discuss diagnosis, prescription, applicator selection, and set-up. Peer review reduces the likelihood of an inappropriate treatment regime. -A template for HDR skin treatments was established in the clinical EMR system to standardize treatment instructions. This reduces the chances of miscommunication between the physician and planning physicist, and increases the detectability of an error during the physics second check. -A screen check was implemented during the second check to increase detectability of an error. -To reduce error probability, the treatment plan worksheet was designed to display plan parameters in a format visually similar to the treatment console display. This facilitates data entry and verification. -VLAs are color-coded and labeled to match the EMR prescriptions, which simplifies in-room selection and verification. Conclusion: Multidisciplinary planning and FMEA increased delectability and reduced error probability during VLA HDR Brachytherapy. This clinical model may be useful to institutions implementing similar procedures.« less

Error Analysis of non-TLD HDR Brachytherapy Dosimetric Techniques

NASA Astrophysics Data System (ADS)

Amoush, Ahmad

The American Association of Physicists in Medicine Task Group Report43 (AAPM-TG43) and its updated version TG-43U1 rely on the LiF TLD detector to determine the experimental absolute dose rate for brachytherapy. The recommended uncertainty estimates associated with TLD experimental dosimetry include 5% for statistical errors (Type A) and 7% for systematic errors (Type B). TG-43U1 protocol does not include recommendation for other experimental dosimetric techniques to calculate the absolute dose for brachytherapy. This research used two independent experimental methods and Monte Carlo simulations to investigate and analyze uncertainties and errors associated with absolute dosimetry of HDR brachytherapy for a Tandem applicator. An A16 MicroChamber* and one dose MOSFET detectors† were selected to meet the TG-43U1 recommendations for experimental dosimetry. Statistical and systematic uncertainty analyses associated with each experimental technique were analyzed quantitatively using MCNPX 2.6‡ to evaluate source positional error, Tandem positional error, the source spectrum, phantom size effect, reproducibility, temperature and pressure effects, volume averaging, stem and wall effects, and Tandem effect. Absolute dose calculations for clinical use are based on Treatment Planning System (TPS) with no corrections for the above uncertainties. Absolute dose and uncertainties along the transverse plane were predicted for the A16 microchamber. The generated overall uncertainties are 22%, 17%, 15%, 15%, 16%, 17%, and 19% at 1cm, 2cm, 3cm, 4cm, and 5cm, respectively. Predicting the dose beyond 5cm is complicated due to low signal-to-noise ratio, cable effect, and stem effect for the A16 microchamber. Since dose beyond 5cm adds no clinical information, it has been ignored in this study. The absolute dose was predicted for the MOSFET detector from 1cm to 7cm along the transverse plane. The generated overall uncertainties are 23%, 11%, 8%, 7%, 7%, 9%, and 8% at 1cm, 2cm, 3cm, and 4cm, 5cm, 6cm, and 7cm, respectively. The Nucletron Freiburg flap applicator is used with the Nucletron remote afterloader HDR machine to deliver dose to surface cancers. Dosimetric data for the Nucletron 192Ir source were generated using Monte Carlo simulation and compared with the published data. Two dimensional dosimetric data were calculated at two source positions; at the center of the sphere of the applicator and between two adjacent spheres. Unlike the TPS dose algorithm, The Monte Carlo code developed for this research accounts for the applicator material, secondary electrons and delta particles, and the air gap between the skin and the applicator. *Standard Imaging, Inc., Middleton, Wisconsin USA † OneDose MOSFET, Sicel Technologies, Morrisville NC ‡ Los Alamos National Laboratory, NM USA

In vivo dosimeters for HDR brachytherapy: a comparison of a diamond detector, MOSFET, TLD, and scintillation detector.

PubMed

Lambert, Jamil; Nakano, Tatsuya; Law, Sue; Elsey, Justin; McKenzie, David R; Suchowerska, Natalka

2007-05-01

The large dose gradients in brachytherapy necessitate a detector with a small active volume for accurate dosimetry. The dosimetric performance of a novel scintillation detector (BrachyFOD) is evaluated and compared to three commercially available detectors, a diamond detector, a MOSFET, and LiF TLDs. An 192Ir HDR brachytherapy source is used to measure the depth dependence, angular dependence, and temperature dependence of the detectors. Of the commercially available detectors, the diamond detector was found to be the most accurate, but has a large physical size. The TLDs cannot provide real time readings and have depth dependent sensitivity. The MOSFET used in this study was accurate to within 5% for distances of 20 to 50 mm from the 192Ir source in water but gave errors of 30%-40% for distances greater than 50 mm from the source. The BrachyFOD was found to be accurate to within 3% for distances of 10 to 100 mm from an HDR 192Ir brachytherapy source in water. It has an angular dependence of less than 2% and the background signal created by Cerenkov radiation and fluorescence of the plastic optical fiber is insignificant compared to the signal generated in the scintillator. Of the four detectors compared in this study the BrachyFOD has the most favorable combination of characteristics for dosimetry in HDR brachytherapy.

Interactive multiobjective optimization for anatomy-based three-dimensional HDR brachytherapy

NASA Astrophysics Data System (ADS)

Ruotsalainen, Henri; Miettinen, Kaisa; Palmgren, Jan-Erik; Lahtinen, Tapani

2010-08-01

In this paper, we present an anatomy-based three-dimensional dose optimization approach for HDR brachytherapy using interactive multiobjective optimization (IMOO). In brachytherapy, the goals are to irradiate a tumor without causing damage to healthy tissue. These goals are often conflicting, i.e. when one target is optimized the other will suffer, and the solution is a compromise between them. IMOO is capable of handling multiple and strongly conflicting objectives in a convenient way. With the IMOO approach, a treatment planner's knowledge is used to direct the optimization process. Thus, the weaknesses of widely used optimization techniques (e.g. defining weights, computational burden and trial-and-error planning) can be avoided, planning times can be shortened and the number of solutions to be calculated is small. Further, plan quality can be improved by finding advantageous trade-offs between the solutions. In addition, our approach offers an easy way to navigate among the obtained Pareto optimal solutions (i.e. different treatment plans). When considering a simulation model of clinical 3D HDR brachytherapy, the number of variables is significantly smaller compared to IMRT, for example. Thus, when solving the model, the CPU time is relatively short. This makes it possible to exploit IMOO to solve a 3D HDR brachytherapy optimization problem. To demonstrate the advantages of IMOO, two clinical examples of optimizing a gynecologic cervix cancer treatment plan are presented.

Evaluation of an active magnetic resonance tracking system for interstitial brachytherapy.

PubMed

Wang, Wei; Viswanathan, Akila N; Damato, Antonio L; Chen, Yue; Tse, Zion; Pan, Li; Tokuda, Junichi; Seethamraju, Ravi T; Dumoulin, Charles L; Schmidt, Ehud J; Cormack, Robert A

2015-12-01

In gynecologic cancers, magnetic resonance (MR) imaging is the modality of choice for visualizing tumors and their surroundings because of superior soft-tissue contrast. Real-time MR guidance of catheter placement in interstitial brachytherapy facilitates target coverage, and would be further improved by providing intraprocedural estimates of dosimetric coverage. A major obstacle to intraprocedural dosimetry is the time needed for catheter trajectory reconstruction. Herein the authors evaluate an active MR tracking (MRTR) system which provides rapid catheter tip localization and trajectory reconstruction. The authors assess the reliability and spatial accuracy of the MRTR system in comparison to standard catheter digitization using magnetic resonance imaging (MRI) and CT. The MRTR system includes a stylet with microcoils mounted on its shaft, which can be inserted into brachytherapy catheters and tracked by a dedicated MRTR sequence. Catheter tip localization errors of the MRTR system and their dependence on catheter locations and orientation inside the MR scanner were quantified with a water phantom. The distances between the tracked tip positions of the MRTR stylet and the predefined ground-truth tip positions were calculated for measurements performed at seven locations and with nine orientations. To evaluate catheter trajectory reconstruction, fifteen brachytherapy catheters were placed into a gel phantom with an embedded catheter fixation framework, with parallel or crossed paths. The MRTR stylet was then inserted sequentially into each catheter. During the removal of the MRTR stylet from within each catheter, a MRTR measurement was performed at 40 Hz to acquire the instantaneous stylet tip position, resulting in a series of three-dimensional (3D) positions along the catheter's trajectory. A 3D polynomial curve was fit to the tracked positions for each catheter, and equally spaced dwell points were then generated along the curve. High-resolution 3D MRI of the phantom was performed followed by catheter digitization based on the catheter's imaging artifacts. The catheter trajectory error was characterized in terms of the mean distance between corresponding dwell points in MRTR-generated catheter trajectory and MRI-based catheter digitization. The MRTR-based catheter trajectory reconstruction process was also performed on three gynecologic cancer patients, and then compared with catheter digitization based on MRI and CT. The catheter tip localization error increased as the MRTR stylet moved further off-center and as the stylet's orientation deviated from the main magnetic field direction. Fifteen catheters' trajectories were reconstructed by MRTR. Compared with MRI-based digitization, the mean 3D error of MRTR-generated trajectories was 1.5 ± 0.5 mm with an in-plane error of 0.7 ± 0.2 mm and a tip error of 1.7 ± 0.5 mm. MRTR resolved ambiguity in catheter assignment due to crossed catheter paths, which is a common problem in image-based catheter digitization. In the patient studies, the MRTR-generated catheter trajectory was consistent with digitization based on both MRI and CT. The MRTR system provides accurate catheter tip localization and trajectory reconstruction in the MR environment. Relative to the image-based methods, it improves the speed, safety, and reliability of the catheter trajectory reconstruction in interstitial brachytherapy. MRTR may enable in-procedural dosimetric evaluation of implant target coverage.

Evaluation of an active magnetic resonance tracking system for interstitial brachytherapy

PubMed Central

Wang, Wei; Viswanathan, Akila N.; Damato, Antonio L.; Chen, Yue; Tse, Zion; Pan, Li; Tokuda, Junichi; Seethamraju, Ravi T.; Dumoulin, Charles L.; Schmidt, Ehud J.; Cormack, Robert A.

2015-01-01

Purpose: In gynecologic cancers, magnetic resonance (MR) imaging is the modality of choice for visualizing tumors and their surroundings because of superior soft-tissue contrast. Real-time MR guidance of catheter placement in interstitial brachytherapy facilitates target coverage, and would be further improved by providing intraprocedural estimates of dosimetric coverage. A major obstacle to intraprocedural dosimetry is the time needed for catheter trajectory reconstruction. Herein the authors evaluate an active MR tracking (MRTR) system which provides rapid catheter tip localization and trajectory reconstruction. The authors assess the reliability and spatial accuracy of the MRTR system in comparison to standard catheter digitization using magnetic resonance imaging (MRI) and CT. Methods: The MRTR system includes a stylet with microcoils mounted on its shaft, which can be inserted into brachytherapy catheters and tracked by a dedicated MRTR sequence. Catheter tip localization errors of the MRTR system and their dependence on catheter locations and orientation inside the MR scanner were quantified with a water phantom. The distances between the tracked tip positions of the MRTR stylet and the predefined ground-truth tip positions were calculated for measurements performed at seven locations and with nine orientations. To evaluate catheter trajectory reconstruction, fifteen brachytherapy catheters were placed into a gel phantom with an embedded catheter fixation framework, with parallel or crossed paths. The MRTR stylet was then inserted sequentially into each catheter. During the removal of the MRTR stylet from within each catheter, a MRTR measurement was performed at 40 Hz to acquire the instantaneous stylet tip position, resulting in a series of three-dimensional (3D) positions along the catheter’s trajectory. A 3D polynomial curve was fit to the tracked positions for each catheter, and equally spaced dwell points were then generated along the curve. High-resolution 3D MRI of the phantom was performed followed by catheter digitization based on the catheter’s imaging artifacts. The catheter trajectory error was characterized in terms of the mean distance between corresponding dwell points in MRTR-generated catheter trajectory and MRI-based catheter digitization. The MRTR-based catheter trajectory reconstruction process was also performed on three gynecologic cancer patients, and then compared with catheter digitization based on MRI and CT. Results: The catheter tip localization error increased as the MRTR stylet moved further off-center and as the stylet’s orientation deviated from the main magnetic field direction. Fifteen catheters’ trajectories were reconstructed by MRTR. Compared with MRI-based digitization, the mean 3D error of MRTR-generated trajectories was 1.5 ± 0.5 mm with an in-plane error of 0.7 ± 0.2 mm and a tip error of 1.7 ± 0.5 mm. MRTR resolved ambiguity in catheter assignment due to crossed catheter paths, which is a common problem in image-based catheter digitization. In the patient studies, the MRTR-generated catheter trajectory was consistent with digitization based on both MRI and CT. Conclusions: The MRTR system provides accurate catheter tip localization and trajectory reconstruction in the MR environment. Relative to the image-based methods, it improves the speed, safety, and reliability of the catheter trajectory reconstruction in interstitial brachytherapy. MRTR may enable in-procedural dosimetric evaluation of implant target coverage. PMID:26632065

Evaluation of an active magnetic resonance tracking system for interstitial brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Wei, E-mail: wwang21@partners.org; Viswanathan, Akila N.; Damato, Antonio L.

2015-12-15

Purpose: In gynecologic cancers, magnetic resonance (MR) imaging is the modality of choice for visualizing tumors and their surroundings because of superior soft-tissue contrast. Real-time MR guidance of catheter placement in interstitial brachytherapy facilitates target coverage, and would be further improved by providing intraprocedural estimates of dosimetric coverage. A major obstacle to intraprocedural dosimetry is the time needed for catheter trajectory reconstruction. Herein the authors evaluate an active MR tracking (MRTR) system which provides rapid catheter tip localization and trajectory reconstruction. The authors assess the reliability and spatial accuracy of the MRTR system in comparison to standard catheter digitization usingmore » magnetic resonance imaging (MRI) and CT. Methods: The MRTR system includes a stylet with microcoils mounted on its shaft, which can be inserted into brachytherapy catheters and tracked by a dedicated MRTR sequence. Catheter tip localization errors of the MRTR system and their dependence on catheter locations and orientation inside the MR scanner were quantified with a water phantom. The distances between the tracked tip positions of the MRTR stylet and the predefined ground-truth tip positions were calculated for measurements performed at seven locations and with nine orientations. To evaluate catheter trajectory reconstruction, fifteen brachytherapy catheters were placed into a gel phantom with an embedded catheter fixation framework, with parallel or crossed paths. The MRTR stylet was then inserted sequentially into each catheter. During the removal of the MRTR stylet from within each catheter, a MRTR measurement was performed at 40 Hz to acquire the instantaneous stylet tip position, resulting in a series of three-dimensional (3D) positions along the catheter’s trajectory. A 3D polynomial curve was fit to the tracked positions for each catheter, and equally spaced dwell points were then generated along the curve. High-resolution 3D MRI of the phantom was performed followed by catheter digitization based on the catheter’s imaging artifacts. The catheter trajectory error was characterized in terms of the mean distance between corresponding dwell points in MRTR-generated catheter trajectory and MRI-based catheter digitization. The MRTR-based catheter trajectory reconstruction process was also performed on three gynecologic cancer patients, and then compared with catheter digitization based on MRI and CT. Results: The catheter tip localization error increased as the MRTR stylet moved further off-center and as the stylet’s orientation deviated from the main magnetic field direction. Fifteen catheters’ trajectories were reconstructed by MRTR. Compared with MRI-based digitization, the mean 3D error of MRTR-generated trajectories was 1.5 ± 0.5 mm with an in-plane error of 0.7 ± 0.2 mm and a tip error of 1.7 ± 0.5 mm. MRTR resolved ambiguity in catheter assignment due to crossed catheter paths, which is a common problem in image-based catheter digitization. In the patient studies, the MRTR-generated catheter trajectory was consistent with digitization based on both MRI and CT. Conclusions: The MRTR system provides accurate catheter tip localization and trajectory reconstruction in the MR environment. Relative to the image-based methods, it improves the speed, safety, and reliability of the catheter trajectory reconstruction in interstitial brachytherapy. MRTR may enable in-procedural dosimetric evaluation of implant target coverage.« less

Reconstruction of brachytherapy seed positions and orientations from cone-beam CT x-ray projections via a novel iterative forward projection matching method.

PubMed

Pokhrel, Damodar; Murphy, Martin J; Todor, Dorin A; Weiss, Elisabeth; Williamson, Jeffrey F

2011-01-01

To generalize and experimentally validate a novel algorithm for reconstructing the 3D pose (position and orientation) of implanted brachytherapy seeds from a set of a few measured 2D cone-beam CT (CBCT) x-ray projections. The iterative forward projection matching (IFPM) algorithm was generalized to reconstruct the 3D pose, as well as the centroid, of brachytherapy seeds from three to ten measured 2D projections. The gIFPM algorithm finds the set of seed poses that minimizes the sum-of-squared-difference of the pixel-by-pixel intensities between computed and measured autosegmented radiographic projections of the implant. Numerical simulations of clinically realistic brachytherapy seed configurations were performed to demonstrate the proof of principle. An in-house machined brachytherapy phantom, which supports precise specification of seed position and orientation at known values for simulated implant geometries, was used to experimentally validate this algorithm. The phantom was scanned on an ACUITY CBCT digital simulator over a full 660 sinogram projections. Three to ten x-ray images were selected from the full set of CBCT sinogram projections and postprocessed to create binary seed-only images. In the numerical simulations, seed reconstruction position and orientation errors were approximately 0.6 mm and 5 degrees, respectively. The physical phantom measurements demonstrated an absolute positional accuracy of (0.78 +/- 0.57) mm or less. The theta and phi angle errors were found to be (5.7 +/- 4.9) degrees and (6.0 +/- 4.1) degrees, respectively, or less when using three projections; with six projections, results were slightly better. The mean registration error was better than 1 mm/6 degrees compared to the measured seed projections. Each test trial converged in 10-20 iterations with computation time of 12-18 min/iteration on a 1 GHz processor. This work describes a novel, accurate, and completely automatic method for reconstructing seed orientations, as well as centroids, from a small number of radiographic projections, in support of intraoperative planning and adaptive replanning. Unlike standard back-projection methods, gIFPM avoids the need to match corresponding seed images on the projections. This algorithm also successfully reconstructs overlapping clustered and highly migrated seeds in the implant. The accuracy of better than 1 mm and 6 degrees demonstrates that gIFPM has the potential to support 2D Task Group 43 calculations in clinical practice.

Reconstruction of brachytherapy seed positions and orientations from cone-beam CT x-ray projections via a novel iterative forward projection matching method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pokhrel, Damodar; Murphy, Martin J.; Todor, Dorin A.

2011-01-15

Purpose: To generalize and experimentally validate a novel algorithm for reconstructing the 3D pose (position and orientation) of implanted brachytherapy seeds from a set of a few measured 2D cone-beam CT (CBCT) x-ray projections. Methods: The iterative forward projection matching (IFPM) algorithm was generalized to reconstruct the 3D pose, as well as the centroid, of brachytherapy seeds from three to ten measured 2D projections. The gIFPM algorithm finds the set of seed poses that minimizes the sum-of-squared-difference of the pixel-by-pixel intensities between computed and measured autosegmented radiographic projections of the implant. Numerical simulations of clinically realistic brachytherapy seed configurations weremore » performed to demonstrate the proof of principle. An in-house machined brachytherapy phantom, which supports precise specification of seed position and orientation at known values for simulated implant geometries, was used to experimentally validate this algorithm. The phantom was scanned on an ACUITY CBCT digital simulator over a full 660 sinogram projections. Three to ten x-ray images were selected from the full set of CBCT sinogram projections and postprocessed to create binary seed-only images. Results: In the numerical simulations, seed reconstruction position and orientation errors were approximately 0.6 mm and 5 deg., respectively. The physical phantom measurements demonstrated an absolute positional accuracy of (0.78{+-}0.57) mm or less. The {theta} and {phi} angle errors were found to be (5.7{+-}4.9) deg. and (6.0{+-}4.1) deg., respectively, or less when using three projections; with six projections, results were slightly better. The mean registration error was better than 1 mm/6 deg. compared to the measured seed projections. Each test trial converged in 10-20 iterations with computation time of 12-18 min/iteration on a 1 GHz processor. Conclusions: This work describes a novel, accurate, and completely automatic method for reconstructing seed orientations, as well as centroids, from a small number of radiographic projections, in support of intraoperative planning and adaptive replanning. Unlike standard back-projection methods, gIFPM avoids the need to match corresponding seed images on the projections. This algorithm also successfully reconstructs overlapping clustered and highly migrated seeds in the implant. The accuracy of better than 1 mm and 6 deg. demonstrates that gIFPM has the potential to support 2D Task Group 43 calculations in clinical practice.« less

SU-F-T-24: Impact of Source Position and Dose Distribution Due to Curvature of HDR Transfer Tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khan, A; Yue, N

2016-06-15

Purpose: Brachytherapy is a highly targeted from of radiotherapy. While this may lead to ideal dose distributions on the treatment planning system, a small error in source location can lead to change in the dose distribution. The purpose of this study is to quantify the impact on source position error due to curvature of the transfer tubes and the impact this may have on the dose distribution. Methods: Since the source travels along the midline of the tube, an estimate of the positioning error for various angles of curvature was determined using geometric properties of the tube. Based on themore » range of values a specific shift was chosen to alter the treatment plans for a number of cervical cancer patients who had undergone HDR brachytherapy boost using tandem and ovoids. Impact of dose to target and organs at risk were determined and checked against guidelines outlined by radiation oncologist. Results: The estimate of the positioning error was 2mm short of the expected position (the curved tube can only cause the source to not reach as far as with a flat tube). Quantitative impact on the dose distribution is still in the process of being analyzed. Conclusion: The accepted positioning tolerance for the source position of a HDR brachytherapy unit is plus or minus 1mm. If there is an additional 2mm discrepancy due to tube curvature, this can result in a source being 1mm to 3mm short of the expected location. While we do always attempt to keep the tubes straight, in some cases such as with tandem and ovoids, the tandem connector does not extend as far out from the patient so the ovoid tubes always contain some degree of curvature. The dose impact of this may be significant.« less

SU-F-T-29: The Important of Each Fraction Image-Guided Planning for Postoperative HDR-Brachytherapy in Endometrial Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piriyasang, D; Pattaranutaporn, P; Manokhoon, K

2016-06-15

Purpose: Cylindrical applicators are often used for postoperative HDRbrachytherapy in endometrial carcinoma. It has been considered that dosimetric variation between fractions for this treatment is minimal and might not be necessary to perform treatment planning for every fractions. At our institute, it is traditional to perform treatment planning with CT simulation on the first fraction and uses this plan for the rest of treatment. This study was aim to evaluate the errors of critical structure doses between the fractions when simulation and planning were done for first fraction only. Methods: Treatment plans of 10 endometrial carcinoma patients who received postoperativemore » HDR-brachytherapy and underwent CT-simulation for every HDR-fractions at our department were retrospectively reviewed. All of these patients were treated with cylindrical applicator and prescribed dose 15Gy in 3 fractions to 0.5cm from vaginal surface. The treatment plan from the first fraction was used to simulate in second and third CT-simulation. Radiation dose for critical structures in term of Dose-to-2cc (D2cc) were evaluated and compared between planning CT. Results: The D2cc for bladder and rectum were evaluated. For bladder, the mean error of D2cc estimation for second and third fractions was 7.6% (0.1–20.1%, SD=5.7). And the mean error for D2cc of rectum was 8.5% (0.1–29.4%, SD=8.5). Conclusion: The critical structure doses could be significant difference between fractions which may affects treatment outcomes or toxicities. From our data, image-guided brachytherapy at least with CT-Simulation should be done for every treatment fractions.« less

Scintillating fiber optic dosimeters for breast and prostate brachytherapy

NASA Astrophysics Data System (ADS)

Moutinho, L. M.; Castro, I. F.; Freitas, H.; Melo, J.; Silva, P.; Gonçalves, A.; Peralta, L.; Rachinhas, P. J.; Simões, P. C. P. S.; Pinto, S.; Pereira, A.; Santos, J. A. M.; Costa, M.; Veloso, J. F. C. A.

2017-02-01

Brachytherapy is a radiotherapy modality where the radioactive material is placed close to the tumor, being a common treatment for skin, breast, gynecological and prostate cancers. These treatments can be of low-dose-rate, using isotopes with mean energy of 30 keV, or high-dose-rate, using isotopes such as 192Ir with a mean energy of 380 keV. Currently these treatments are performed in most cases without in-vivo dosimetry for quality control and quality assurance. We developed a dosimeter using small diameter probes that can be inserted into the patient's body using standard brachytherapy needles. By performing real-time dosimetry in breast and prostate brachytherapy it will be possible to perform real-time dose correction when deviations from the treatment plan are observed. The dosimeter presented in this work was evaluated in-vitro. The studies consisted in the characterization of the dosimeter with 500 μm diameter sensitive probes (with a BCF-12 scintillating optical fiber) using an inhouse made gelatin breast phantom with a volume of 566 cm3. A breast brachytherapy treatment was simulated considering a tumor volume of 27 cm3 and a prescribed absolute dose of 5 Gy. The dose distribution was determined by the Inverse Planning Simulated Annealing (IPSA) optimization algorithm (ELEKTA). The dwell times estimated from the experimental measurements are in agreement with the prescribed dwell times, with relative error below 3%. The measured signal-to-noise ratio (SNR) including the stem-effect contribution is below 3%.

SU-E-J-81: Beveled Needle Tip Detection Error in Ultrasound-Guided Prostate Brachytherapy.

PubMed

Leu, S; Ruiz, B; Podder, T

2012-06-01

To quantify the needle tip detection errors in ultrasound images due to bevel-tip orientation in relation to the location on template grid. Transrectal ultrasound (TRUS) system (BK Medical) with physical template grid and 18-gauge bevel-tip (20-deg beveled angle) brachytherapy needle (Bard Medical, Covington, GA) were used. The TRUS was set at 6.5MHz in water phantom at 40°C and measurements were taken with 50% and 100% TRUS gains. Needles were oriented with bevel-tip facing up (0-degree) and inserted through template grid-holes. Reference needle depths were measured when needle tip image intensity was bright enough for potentially consistent readings. High-resolution digital vernier caliper was used to measure needle depth. Needle bevel-tip orientation was then changed to bevel down (by rotating 180-degree) and needle depth was adjusted by retracting so that the needle-tip image intensity appeared similar to when the needle bevel-tip was at 0-degree orientation. Clinically relevant locations were considered for needle placement on the template grids (1st row to 9th row, and 'a-f' columns). For 50% TRUS gain, bevel tip detection errors/differences were 0.69±0.30mm (1st row) to 3.23±0.22mm (9th row) and 0.78±0.71mm (1st row) to 4.14±0.56mm (9th row) in columns 'a' and 'D', respectively. The corresponding errors for 100% TRUS gain were 0.57±0.25mm to 5.24±0.36mm and 0.84±0.30mm to 4.2±0.20mm in columns 'a' and 'D', respectively. These errors/differences varied linearly for grid-hole locations on the rows and columns in between, smaller to large depending on distance from the TRUS probe. Observed no effect of gains (50% vs. 100%) along 'D' column, which was directly above the TRUS probe. Experiment results revealed that the beveled needle tip orientation could significantly impact the detection accuracy of the needle tips, based on which the seeds might be delivered. These errors may lead to considerable dosimetric deviations in prostate brachytherapy seed implantation. © 2012 American Association of Physicists in Medicine.

Robotic Assistance for Ultrasound-Guided Prostate Brachytherapy

PubMed Central

Fichtinger, Gabor; Fiene, Jonathan P.; Kennedy, Christopher W.; Kronreif, Gernot; Iordachita, Iulian; Song, Danny Y.; Burdette, Everette C.; Kazanzides, Peter

2016-01-01

We present a robotically assisted prostate brachytherapy system and test results in training phantoms and Phase-I clinical trials. The system consists of a transrectal ultrasound (TRUS) and a spatially co-registered robot, fully integrated with an FDA-approved commercial treatment planning system. The salient feature of the system is a small parallel robot affixed to the mounting posts of the template. The robot replaces the template interchangeably, using the same coordinate system. Established clinical hardware, workflow and calibration remain intact. In all phantom experiments, we recorded the first insertion attempt without adjustment. All clinically relevant locations in the prostate were reached. Non-parallel needle trajectories were achieved. The pre-insertion transverse and rotational errors (measured with a Polaris optical tracker relative to the template’s coordinate frame) were 0.25mm (STD=0.17mm) and 0.75° (STD=0.37°). In phantoms, needle tip placement errors measured in TRUS were 1.04mm (STD=0.50mm). A Phase-I clinical feasibility and safety trial has been successfully completed with the system. We encountered needle tip positioning errors of a magnitude greater than 4mm in only 2 out of 179 robotically guided needles, in contrast to manual template guidance where errors of this magnitude are much more common. Further clinical trials are necessary to determine whether the apparent benefits of the robotic assistant will lead to improvements in clinical efficacy and outcomes. PMID:18650122

[A Quality Assurance (QA) System with a Web Camera for High-dose-rate Brachytherapy].

PubMed

Hirose, Asako; Ueda, Yoshihiro; Oohira, Shingo; Isono, Masaru; Tsujii, Katsutomo; Inui, Shouki; Masaoka, Akira; Taniguchi, Makoto; Miyazaki, Masayoshi; Teshima, Teruki

2016-03-01

The quality assurance (QA) system that simultaneously quantifies the position and duration of an (192)Ir source (dwell position and time) was developed and the performance of this system was evaluated in high-dose-rate brachytherapy. This QA system has two functions to verify and quantify dwell position and time by using a web camera. The web camera records 30 images per second in a range from 1,425 mm to 1,505 mm. A user verifies the source position from the web camera at real time. The source position and duration were quantified with the movie using in-house software which was applied with a template-matching technique. This QA system allowed verification of the absolute position in real time and quantification of dwell position and time simultaneously. It was evident from the verification of the system that the mean of step size errors was 0.31±0.1 mm and that of dwell time errors 0.1±0.0 s. Absolute position errors can be determined with an accuracy of 1.0 mm at all dwell points in three step sizes and dwell time errors with an accuracy of 0.1% in more than 10.0 s of the planned time. This system is to provide quick verification and quantification of the dwell position and time with high accuracy at various dwell positions without depending on the step size.

Automated high-dose rate brachytherapy treatment planning for a single-channel vaginal cylinder applicator

NASA Astrophysics Data System (ADS)

Zhou, Yuhong; Klages, Peter; Tan, Jun; Chi, Yujie; Stojadinovic, Strahinja; Yang, Ming; Hrycushko, Brian; Medin, Paul; Pompos, Arnold; Jiang, Steve; Albuquerque, Kevin; Jia, Xun

2017-06-01

High dose rate (HDR) brachytherapy treatment planning is conventionally performed manually and/or with aids of preplanned templates. In general, the standard of care would be elevated by conducting an automated process to improve treatment planning efficiency, eliminate human error, and reduce plan quality variations. Thus, our group is developing AutoBrachy, an automated HDR brachytherapy planning suite of modules used to augment a clinical treatment planning system. This paper describes our proof-of-concept module for vaginal cylinder HDR planning that has been fully developed. After a patient CT scan is acquired, the cylinder applicator is automatically segmented using image-processing techniques. The target CTV is generated based on physician-specified treatment depth and length. Locations of the dose calculation point, apex point and vaginal surface point, as well as the central applicator channel coordinates, and the corresponding dwell positions are determined according to their geometric relationship with the applicator and written to a structure file. Dwell times are computed through iterative quadratic optimization techniques. The planning information is then transferred to the treatment planning system through a DICOM-RT interface. The entire process was tested for nine patients. The AutoBrachy cylindrical applicator module was able to generate treatment plans for these cases with clinical grade quality. Computation times varied between 1 and 3 min on an Intel Xeon CPU E3-1226 v3 processor. All geometric components in the automated treatment plans were generated accurately. The applicator channel tip positions agreed with the manually identified positions with submillimeter deviations and the channel orientations between the plans agreed within less than 1 degree. The automatically generated plans obtained clinically acceptable quality.

A system to use electromagnetic tracking for the quality assurance of brachytherapy catheter digitization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Damato, Antonio L., E-mail: adamato@lroc.harvard.edu; Viswanathan, Akila N.; Don, Sarah M.

2014-10-15

Purpose: To investigate the use of a system using electromagnetic tracking (EMT), post-processing and an error-detection algorithm for detecting errors and resolving uncertainties in high-dose-rate brachytherapy catheter digitization for treatment planning. Methods: EMT was used to localize 15 catheters inserted into a phantom using a stepwise acquisition technique. Five distinct acquisition experiments were performed. Noise associated with the acquisition was calculated. The dwell location configuration was extracted from the EMT data. A CT scan of the phantom was performed, and five distinct catheter digitization sessions were performed. No a priori registration of the CT scan coordinate system with the EMTmore » coordinate system was performed. CT-based digitization was automatically extracted from the brachytherapy plan DICOM files (CT), and rigid registration was performed between EMT and CT dwell positions. EMT registration error was characterized in terms of the mean and maximum distance between corresponding EMT and CT dwell positions per catheter. An algorithm for error detection and identification was presented. Three types of errors were systematically simulated: swap of two catheter numbers, partial swap of catheter number identification for parts of the catheters (mix), and catheter-tip shift. Error-detection sensitivity (number of simulated scenarios correctly identified as containing an error/number of simulated scenarios containing an error) and specificity (number of scenarios correctly identified as not containing errors/number of correct scenarios) were calculated. Catheter identification sensitivity (number of catheters correctly identified as erroneous across all scenarios/number of erroneous catheters across all scenarios) and specificity (number of catheters correctly identified as correct across all scenarios/number of correct catheters across all scenarios) were calculated. The mean detected and identified shift was calculated. Results: The maximum noise ±1 standard deviation associated with the EMT acquisitions was 1.0 ± 0.1 mm, and the mean noise was 0.6 ± 0.1 mm. Registration of all the EMT and CT dwell positions was associated with a mean catheter error of 0.6 ± 0.2 mm, a maximum catheter error of 0.9 ± 0.4 mm, a mean dwell error of 1.0 ± 0.3 mm, and a maximum dwell error of 1.3 ± 0.7 mm. Error detection and catheter identification sensitivity and specificity of 100% were observed for swap, mix and shift (≥2.6 mm for error detection; ≥2.7 mm for catheter identification) errors. A mean detected shift of 1.8 ± 0.4 mm and a mean identified shift of 1.9 ± 0.4 mm were observed. Conclusions: Registration of the EMT dwell positions to the CT dwell positions was possible with a residual mean error per catheter of 0.6 ± 0.2 mm and a maximum error for any dwell of 1.3 ± 0.7 mm. These low residual registration errors show that quality assurance of the general characteristics of the catheters and of possible errors affecting one specific dwell position is possible. The sensitivity and specificity of the catheter digitization verification algorithm was 100% for swap and mix errors and for shifts ≥2.6 mm. On average, shifts ≥1.8 mm were detected, and shifts ≥1.9 mm were detected and identified.« less

Gold nanoparticle‐based brachytherapy enhancement in choroidal melanoma using a full Monte Carlo model of the human eye

PubMed Central

Vaez‐zadeh, Mehdi; Masoudi, S. Farhad; Rahmani, Faezeh; Knaup, Courtney; Meigooni, Ali S.

2015-01-01

The effects of gold nanoparticles (GNPs) in 125I brachytherapy dose enhancement on choroidal melanoma are examined using the Monte Carlo simulation technique. Usually, Monte Carlo ophthalmic brachytherapy dosimetry is performed in a water phantom. However, here, the compositions of human eye have been considered instead of water. Both human eye and water phantoms have been simulated with MCNP5 code. These simulations were performed for a fully loaded 16 mm COMS eye plaque containing 13 125I seeds. The dose delivered to the tumor and normal tissues have been calculated in both phantoms with and without GNPs. Normally, the radiation therapy of cancer patients is designed to deliver a required dose to the tumor while sparing the surrounding normal tissues. However, as the normal and cancerous cells absorbed dose in an almost identical fashion, the normal tissue absorbed radiation dose during the treatment time. The use of GNPs in combination with radiotherapy in the treatment of tumor decreases the absorbed dose by normal tissues. The results indicate that the dose to the tumor in an eyeball implanted with COMS plaque increases with increasing GNPs concentration inside the target. Therefore, the required irradiation time for the tumors in the eye is decreased by adding the GNPs prior to treatment. As a result, the dose to normal tissues decreases when the irradiation time is reduced. Furthermore, a comparison between the simulated data in an eye phantom made of water and eye phantom made of human eye composition, in the presence of GNPs, shows the significance of utilizing the composition of eye in ophthalmic brachytherapy dosimetry Also, defining the eye composition instead of water leads to more accurate calculations of GNPs radiation effects in ophthalmic brachytherapy dosimetry. PACS number: 87.53.Jw, 87.85.Rs, 87.10.Rt PMID:26699318

Adaptation of the CVT algorithm for catheter optimization in high dose rate brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poulin, Eric; Fekete, Charles-Antoine Collins; Beaulieu, Luc

2013-11-15

Purpose: An innovative, simple, and fast method to optimize the number and position of catheters is presented for prostate and breast high dose rate (HDR) brachytherapy, both for arbitrary templates or template-free implants (such as robotic templates).Methods: Eight clinical cases were chosen randomly from a bank of patients, previously treated in our clinic to test our method. The 2D Centroidal Voronoi Tessellations (CVT) algorithm was adapted to distribute catheters uniformly in space, within the maximum external contour of the planning target volume. The catheters optimization procedure includes the inverse planning simulated annealing algorithm (IPSA). Complete treatment plans can then bemore » generated from the algorithm for different number of catheters. The best plan is chosen from different dosimetry criteria and will automatically provide the number of catheters and their positions. After the CVT algorithm parameters were optimized for speed and dosimetric results, it was validated against prostate clinical cases, using clinically relevant dose parameters. The robustness to implantation error was also evaluated. Finally, the efficiency of the method was tested in breast interstitial HDR brachytherapy cases.Results: The effect of the number and locations of the catheters on prostate cancer patients was studied. Treatment plans with a better or equivalent dose distributions could be obtained with fewer catheters. A better or equal prostate V100 was obtained down to 12 catheters. Plans with nine or less catheters would not be clinically acceptable in terms of prostate V100 and D90. Implantation errors up to 3 mm were acceptable since no statistical difference was found when compared to 0 mm error (p > 0.05). No significant difference in dosimetric indices was observed for the different combination of parameters within the CVT algorithm. A linear relation was found between the number of random points and the optimization time of the CVT algorithm. Because the computation time decrease with the number of points and that no effects were observed on the dosimetric indices when varying the number of sampling points and the number of iterations, they were respectively fixed to 2500 and to 100. The computation time to obtain ten complete treatments plans ranging from 9 to 18 catheters, with the corresponding dosimetric indices, was 90 s. However, 93% of the computation time is used by a research version of IPSA. For the breast, on average, the Radiation Therapy Oncology Group recommendations would be satisfied down to 12 catheters. Plans with nine or less catheters would not be clinically acceptable in terms of V100, dose homogeneity index, and D90.Conclusions: The authors have devised a simple, fast and efficient method to optimize the number and position of catheters in interstitial HDR brachytherapy. The method was shown to be robust for both prostate and breast HDR brachytherapy. More importantly, the computation time of the algorithm is acceptable for clinical use. Ultimately, this catheter optimization algorithm could be coupled with a 3D ultrasound system to allow real-time guidance and planning in HDR brachytherapy.« less

SU-E-T-68: A Quality Assurance System with a Web Camera for High Dose Rate Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ueda, Y; Hirose, A; Oohira, S

Purpose: The purpose of this work was to develop a quality assurance (QA) system for high dose rate (HDR) brachytherapy to verify the absolute position of an 192Ir source in real time and to measure dwell time and position of the source simultaneously with a movie recorded by a web camera. Methods: A web camera was fixed 15 cm above a source position check ruler to monitor and record 30 samples of the source position per second over a range of 8.0 cm, from 1425 mm to 1505 mm. Each frame had a matrix size of 480×640 in the movie.more » The source position was automatically quantified from the movie using in-house software (built with LabVIEW) that applied a template-matching technique. The source edge detected by the software on each frame was corrected to reduce position errors induced by incident light from an oblique direction. The dwell time was calculated by differential processing to displacement of the source. The performance of this QA system was illustrated by recording simple plans and comparing the measured dwell positions and time with the planned parameters. Results: This QA system allowed verification of the absolute position of the source in real time. The mean difference between automatic and manual detection of the source edge was 0.04 ± 0.04 mm. Absolute position error can be determined within an accuracy of 1.0 mm at dwell points of 1430, 1440, 1450, 1460, 1470, 1480, 1490, and 1500 mm, in three step sizes and dwell time errors, with an accuracy of 0.1% in more than 10.0 sec of planned time. The mean step size error was 0.1 ± 0.1 mm for a step size of 10.0 mm. Conclusion: This QA system provides quick verifications of the dwell position and time, with high accuracy, for HDR brachytherapy. This work was supported by the Japan Society for the Promotion of Science Core-to-Core program (No. 23003)« less

Dosimetric impact of dual-energy CT tissue segmentation for low-energy prostate brachytherapy: a Monte Carlo study

NASA Astrophysics Data System (ADS)

Remy, Charlotte; Lalonde, Arthur; Béliveau-Nadeau, Dominic; Carrier, Jean-François; Bouchard, Hugo

2018-01-01

The purpose of this study is to evaluate the impact of a novel tissue characterization method using dual-energy over single-energy computed tomography (DECT and SECT) on Monte Carlo (MC) dose calculations for low-dose rate (LDR) prostate brachytherapy performed in a patient like geometry. A virtual patient geometry is created using contours from a real patient pelvis CT scan, where known elemental compositions and varying densities are overwritten in each voxel. A second phantom is made with additional calcifications. Both phantoms are the ground truth with which all results are compared. Simulated CT images are generated from them using attenuation coefficients taken from the XCOM database with a 100 kVp spectrum for SECT and 80 and 140Sn kVp for DECT. Tissue segmentation for Monte Carlo dose calculation is made using a stoichiometric calibration method for the simulated SECT images. For the DECT images, Bayesian eigentissue decomposition is used. A LDR prostate brachytherapy plan is defined with 125I sources and then calculated using the EGSnrc user-code Brachydose for each case. Dose distributions and dose-volume histograms (DVH) are compared to ground truth to assess the accuracy of tissue segmentation. For noiseless images, DECT-based tissue segmentation outperforms the SECT procedure with a root mean square error (RMS) on relative errors on dose distributions respectively of 2.39% versus 7.77%, and provides DVHs closest to the reference DVHs for all tissues. For a medium level of CT noise, Bayesian eigentissue decomposition still performs better on the overall dose calculation as the RMS error is found to be of 7.83% compared to 9.15% for SECT. Both methods give a similar DVH for the prostate while the DECT segmentation remains more accurate for organs at risk and in presence of calcifications, with less than 5% of RMS errors within the calcifications versus up to 154% for SECT. In a patient-like geometry, DECT-based tissue segmentation provides dose distributions with the highest accuracy and the least bias compared to SECT. When imaging noise is considered, benefits of DECT are noticeable if important calcifications are found within the prostate.

SU-F-E-02: A Feasibility Study for Application of Metal Artifact Reduction Techniques in MR-Guided Brachytherapy Gynecological Cancer with Titanium Applicators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadbi, M

Purpose: Utilization of Titanium Tandem and Ring (T&R) applicators in MR-guided brachytherapy has become widespread for gynecological cancer treatment. However, Titanium causes magnetic field disturbance and susceptibility artifact, which complicate image interpretation. In this study, metal artifact reduction techniques were employed to improve the image quality and reduce the metal related artifacts. Methods: Several techniques were employed to reduce the metal artifact caused by titanium T&R applicator. These techniques include Metal Artifact Reduction Sequence (MARS), View Angle Tilting (VAT) to correct in-plane distortion, and Slice Encoding for Metal Artifact Correction (SEMAC) for through-plane artifact correction. Moreover, MARS can be combinedmore » with VAT to further reduce the in-plane artifact by reapplying the selection gradients during the readout (MARS+VAT). SEMAC uses a slice selective excitation but acquires additional z-encodings in order to resolve off-resonant signal and to reduce through-plane distortions. Results: Comparison between the clinical sequences revealed that increasing the bandwidth reduces the error in measured diameter of T&R. However, the error is larger than 4mm for the best case with highest bandwidth and spatial resolution. MARS+VAT with isotropic resolution of 1mm reduced the error to 1.9mm which is the least among the examined 2D sequences. The measured diameter of tandem from SEMAC+VAT has the closest value to the actual diameter of tandem (3.2mm) and the error was reduced to less than 1mm. In addition, SEMAC+VAT significantly reduces the blooming artifact in the ring compared to clinical sequences. Conclusion: A higher bandwidth and spatial resolution sequence reduces the artifact and diameter of applicator with a slight compromise in SNR. Metal artifact reduction sequences decrease the distortion associated with titanium applicator. SEMAC+VAT sequence in combination with VAT revealed promising results for titanium imaging and can be utilized for MR-guided brachytherapy in gynecological cancer. The author is employee with Philips Healthcare.« less

Long duration mild temperature hyperthermia and brachytherapy.

PubMed

Armour, E P; Raaphorst, G P

2004-03-01

Combining long duration mild temperature hyperthermia (LDMH) and low dose-rate (LDR) brachytherapy to enhance therapeutic killing of cancer cells was proposed many years ago. The cellular and tumour research that supports this hypothesis is presented in this review. Research describing LDMH interaction with pulsed brachytherapy and high dose-rate brachytherapy using clinically relevant parameters are compared with LDMH/LDR brachytherapy. The mechanism by which LDMH sensitizes LDR has been established as the inhibition of sublethal damage repair. The molecular mechanisms have been shown to involve DNA repair enzymes, but the exact nature of these processes is still under investigation. The relative differences between LDMH interactions with human and rodent cells are presented to help in the understanding of possible roles of LDMH in clinical application. The role of LDMH in modifying tumour blood flow and its possible role in LDR sensitization of tumours is also presented. The positive aspects of LDMH-brachytherapy for clinical application are sixfold; (1) the thermal goals (temperature, time and volume) are achievable with currently available technology, (2) the hyperthermia by itself has no detectable toxic effects, (3) thermotolerance appears to play a minor if any role in radiation sensitization, (4) TER of around 2 can be expected, (5) hypoxic fraction may be decreased due to blood flow modification and (6) simultaneous chemotherapy may also be sensitized. Combined LDMH and brachytherapy is a cancer therapy that has established biological rationale and sufficient technical and clinical advancements to be appropriately applied. This modality is ripe for clinical testing.

Sci—Fri PM: Topics — 08: The Role and Benefits of Electromagnetic Needle-Tracking Technologies in Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beaulieu, L.; Racine, E.; Boutaleb, S.

In modern brachytherapy, application of large doses of ionizing radiation in a limited number of fractions is frequent. Furthermore, as with any surgical procedures, brachytherapy is subject to learning curve effects. In this context, there could be advantages of integrating real-time tracking of needles/catheters to existing protocols given the recent prominent advances in tracking technologies. In this work, we review the use of an electromagnetic tracking system (EMTS) based on the second generation Aurora® Planar Field Generator (Northern Digital Inc) and custom design needles (Philips Healthcare) for brachytherapy applications. The position and orientation information is obtained from 5 degrees ofmore » freedom sensors. Basic system performance characterization is performed in well-controlled conditions to establish accuracy and reproducibility as well as potential interference from standard brachytherapy equipment. The results show that sensor locations can be tracked to within 0.04mm (la) when located within 26cm of the generator. Orientation accuracy of the needle remained within ±1° in the same region, but rose quickly at larger distances. The errors on position and orientation strongly dependent the sensor position in the characterization volume (500×500×500mm{sup 3}). The presence of an ultrasound probe was shown to have negligible effects on tracking accuracy. The use of EMTS for automatic catheter/applicator reconstruction was also explored. Reconstruction time was less than 10 sec/channel and tips identification was within 0.69±0.29mm of the reference values. Finally, we demonstrate that hollow needle designs with special EM adaptation also allow for real-time seed drop position estimation. In phantom experiments showed that drop positions were on average within 1.6±0.9mm of the reference position measured from μCT. Altogether, EMTS offer promising benefits in a wide range of brachytherapy applications.« less

Monte Carlo dose calculations for high-dose-rate brachytherapy using GPU-accelerated processing.

PubMed

Tian, Z; Zhang, M; Hrycushko, B; Albuquerque, K; Jiang, S B; Jia, X

2016-01-01

Current clinical brachytherapy dose calculations are typically based on the Association of American Physicists in Medicine Task Group report 43 (TG-43) guidelines, which approximate patient geometry as an infinitely large water phantom. This ignores patient and applicator geometries and heterogeneities, causing dosimetric errors. Although Monte Carlo (MC) dose calculation is commonly recognized as the most accurate method, its associated long computational time is a major bottleneck for routine clinical applications. This article presents our recent developments of a fast MC dose calculation package for high-dose-rate (HDR) brachytherapy, gBMC, built on a graphics processing unit (GPU) platform. gBMC-simulated photon transport in voxelized geometry with physics in (192)Ir HDR brachytherapy energy range considered. A phase-space file was used as a source model. GPU-based parallel computation was used to simultaneously transport multiple photons, one on a GPU thread. We validated gBMC by comparing the dose calculation results in water with that computed TG-43. We also studied heterogeneous phantom cases and a patient case and compared gBMC results with Acuros BV results. Radial dose function in water calculated by gBMC showed <0.6% relative difference from that of the TG-43 data. Difference in anisotropy function was <1%. In two heterogeneous slab phantoms and one shielded cylinder applicator case, average dose discrepancy between gBMC and Acuros BV was <0.87%. For a tandem and ovoid patient case, good agreement between gBMC and Acruos BV results was observed in both isodose lines and dose-volume histograms. In terms of the efficiency, it took ∼47.5 seconds for gBMC to reach 0.15% statistical uncertainty within the 5% isodose line for the patient case. The accuracy and efficiency of a new GPU-based MC dose calculation package, gBMC, for HDR brachytherapy make it attractive for clinical applications. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Quality assurance for high dose rate brachytherapy treatment planning optimization: using a simple optimization to verify a complex optimization

NASA Astrophysics Data System (ADS)

Deufel, Christopher L.; Furutani, Keith M.

2014-02-01

As dose optimization for high dose rate brachytherapy becomes more complex, it becomes increasingly important to have a means of verifying that optimization results are reasonable. A method is presented for using a simple optimization as quality assurance for the more complex optimization algorithms typically found in commercial brachytherapy treatment planning systems. Quality assurance tests may be performed during commissioning, at regular intervals, and/or on a patient specific basis. A simple optimization method is provided that optimizes conformal target coverage using an exact, variance-based, algebraic approach. Metrics such as dose volume histogram, conformality index, and total reference air kerma agree closely between simple and complex optimizations for breast, cervix, prostate, and planar applicators. The simple optimization is shown to be a sensitive measure for identifying failures in a commercial treatment planning system that are possibly due to operator error or weaknesses in planning system optimization algorithms. Results from the simple optimization are surprisingly similar to the results from a more complex, commercial optimization for several clinical applications. This suggests that there are only modest gains to be made from making brachytherapy optimization more complex. The improvements expected from sophisticated linear optimizations, such as PARETO methods, will largely be in making systems more user friendly and efficient, rather than in finding dramatically better source strength distributions.

WE-A-17A-09: Exploiting Electromagnetic Technologies for Real-Time Seed Drop Position Validation in Permanent Implant Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Racine, E; Hautvast, G; Binnekamp, D

Purpose: To report on preliminary results validating the performance of a specially designed LDR brachytherapy needle prototype possessing both electromagnetic (EM) tracking and seed drop detection abilities. Methods: An EM hollow needle prototype has been designed and constructed in collaboration with research partner Philips Healthcare. The needle possesses conventional 3D tracking capabilities, along with a novel seed drop detection mechanism exploiting local changes of electromagnetic properties generated by the passage of seeds in the needle's embedded sensor coils. These two capabilities are exploited by proprietary engineering and signal processing techniques to generate seed drop position estimates in real-time treatment delivery.more » The electromagnetic tracking system (EMTS) used for the experiment is the NDI Aurora Planar Field Generator. The experiment consisted of dropping a total of 35 seeds in a prismatic agarose phantom, and comparing the 3D seed drop positions of the EMTS to those obtained by an image analysis of subsequent micro-CT scans. Drop position error computations and statistical analysis were performed after a 3D registration of the two seed distributions. Results: Of the 35 seeds dropped in the phantom, 32 were properly detected by the needle prototype. Absolute drop position errors among the detected seeds ranged from 0.5 to 4.8 mm with mean and standard deviation values of 1.6 and 0.9 mm, respectively. Error measurements also include undesirable and uncontrollable effects such as seed motion upon deposition. The true accuracy performance of the needle prototype is therefore underestimated. Conclusion: This preliminary study demonstrates the potential benefits of EM technologies in detecting the passage of seeds in a hollow needle as a means of generating drop position estimates in real-time treatment delivery. Such tools could therefore represent a potentially interesting addition to existing brachytherapy protocols for rapid dosimetry validation. Equipments and fundings for this project were provided by Philips Medical.« less

Adaptive error detection for HDR/PDR brachytherapy: Guidance for decision making during real-time in vivo point dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertzscher, Gustavo, E-mail: guke@dtu.dk; Andersen, Claus E., E-mail: clan@dtu.dk; Tanderup, Kari, E-mail: karitand@rm.dk

Purpose: This study presents an adaptive error detection algorithm (AEDA) for real-timein vivo point dosimetry during high dose rate (HDR) or pulsed dose rate (PDR) brachytherapy (BT) where the error identification, in contrast to existing approaches, does not depend on an a priori reconstruction of the dosimeter position. Instead, the treatment is judged based on dose rate comparisons between measurements and calculations of the most viable dosimeter position provided by the AEDA in a data driven approach. As a result, the AEDA compensates for false error cases related to systematic effects of the dosimeter position reconstruction. Given its nearly exclusivemore » dependence on stable dosimeter positioning, the AEDA allows for a substantially simplified and time efficient real-time in vivo BT dosimetry implementation. Methods: In the event of a measured potential treatment error, the AEDA proposes the most viable dosimeter position out of alternatives to the original reconstruction by means of a data driven matching procedure between dose rate distributions. If measured dose rates do not differ significantly from the most viable alternative, the initial error indication may be attributed to a mispositioned or misreconstructed dosimeter (false error). However, if the error declaration persists, no viable dosimeter position can be found to explain the error, hence the discrepancy is more likely to originate from a misplaced or misreconstructed source applicator or from erroneously connected source guide tubes (true error). Results: The AEDA applied on twoin vivo dosimetry implementations for pulsed dose rate BT demonstrated that the AEDA correctly described effects responsible for initial error indications. The AEDA was able to correctly identify the major part of all permutations of simulated guide tube swap errors and simulated shifts of individual needles from the original reconstruction. Unidentified errors corresponded to scenarios where the dosimeter position was sufficiently symmetric with respect to error and no-error source position constellations. The AEDA was able to correctly identify all false errors represented by mispositioned dosimeters contrary to an error detection algorithm relying on the original reconstruction. Conclusions: The study demonstrates that the AEDA error identification during HDR/PDR BT relies on a stable dosimeter position rather than on an accurate dosimeter reconstruction, and the AEDA’s capacity to distinguish between true and false error scenarios. The study further shows that the AEDA can offer guidance in decision making in the event of potential errors detected with real-timein vivo point dosimetry.« less

A method for verification of treatment delivery in HDR prostate brachytherapy using a flat panel detector for both imaging and source tracking.

PubMed

Smith, Ryan L; Haworth, Annette; Panettieri, Vanessa; Millar, Jeremy L; Franich, Rick D

2016-05-01

Verification of high dose rate (HDR) brachytherapy treatment delivery is an important step, but is generally difficult to achieve. A technique is required to monitor the treatment as it is delivered, allowing comparison with the treatment plan and error detection. In this work, we demonstrate a method for monitoring the treatment as it is delivered and directly comparing the delivered treatment with the treatment plan in the clinical workspace. This treatment verification system is based on a flat panel detector (FPD) used for both pre-treatment imaging and source tracking. A phantom study was conducted to establish the resolution and precision of the system. A pretreatment radiograph of a phantom containing brachytherapy catheters is acquired and registration between the measurement and treatment planning system (TPS) is performed using implanted fiducial markers. The measured catheter paths immediately prior to treatment were then compared with the plan. During treatment delivery, the position of the (192)Ir source is determined at each dwell position by measuring the exit radiation with the FPD and directly compared to the planned source dwell positions. The registration between the two corresponding sets of fiducial markers in the TPS and radiograph yielded a registration error (residual) of 1.0 mm. The measured catheter paths agreed with the planned catheter paths on average to within 0.5 mm. The source positions measured with the FPD matched the planned source positions for all dwells on average within 0.6 mm (s.d. 0.3, min. 0.1, max. 1.4 mm). We have demonstrated a method for directly comparing the treatment plan with the delivered treatment that can be easily implemented in the clinical workspace. Pretreatment imaging was performed, enabling visualization of the implant before treatment delivery and identification of possible catheter displacement. Treatment delivery verification was performed by measuring the source position as each dwell was delivered. This approach using a FPD for imaging and source tracking provides a noninvasive method of acquiring extensive information for verification in HDR prostate brachytherapy.

SU-F-T-09: In Phantom Full-Implant Validation of Plastic Scintillation Detectors for in Vivo Dosimetry During Low Dose Rate Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Therriault-Proulx, F; Bruno, T; Beddar, S

Purpose: To validate in a water phantom the use of plastic scintillation detectors to measure dose to the urethra and the rectal wall during a clinically realistic low dose rate (LDR) brachytherapy implant. Methods: A template was designed to replicate a clinically realistic LDR brachytherapy prostate implant inside a water phantom. Twenty-two catheters were inserted, including one mimicking the urethra and another the rectal wall. The needles inserted in the remaining 20 catheters were composed of thin-walled nylon tubes in which I-125 radioactive seeds (Air Kerma Strengths of (0.328±0.020)U) were abutted together with plastic spacers to replicate a typical loading.more » A plastic scintillation detector (PSD) with a 5-mm long × 1-mm diameter sensitive element was first placed inside the urethra and 1-second measurements were performed for 60s after each needle implant. Measurements were also performed at multiple positions along the urethra once all the needles were inserted. The procedure was then repeated with the PSD placed at the rectal wall. Results: Individual dose-rates ranging from 0.07µGy/s to 1.5µGy/s were measured after each needle implant. The average absolute relative differences were (6.2±3.6)% and (6.9±6.5)% to the values calculated with the TG-43 formalism, for the urethra and rectal wall respectively. These results are within expectations from the error uncertainty budget once accounting for uncertainties in seeds’ strength and positioning. Interestingly, the PSD allowed for unplanned error detection as the study was performed. Finally, the measured dose after the full implant at different positions along the mimicked organs at risk were in agreement with TG-43 values for all of the positions tested. Conclusion: Plastic scintillation detectors could be used as in vivo detectors for LDR brachytherapy as they would provide accurate dose information after each needle implant as well as along the organs at risk at the end of the implant.« less

A method for verification of treatment delivery in HDR prostate brachytherapy using a flat panel detector for both imaging and source tracking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Ryan L., E-mail: ryan.smith@wbrc.org.au; Millar, Jeremy L.; Franich, Rick D.

Purpose: Verification of high dose rate (HDR) brachytherapy treatment delivery is an important step, but is generally difficult to achieve. A technique is required to monitor the treatment as it is delivered, allowing comparison with the treatment plan and error detection. In this work, we demonstrate a method for monitoring the treatment as it is delivered and directly comparing the delivered treatment with the treatment plan in the clinical workspace. This treatment verification system is based on a flat panel detector (FPD) used for both pre-treatment imaging and source tracking. Methods: A phantom study was conducted to establish the resolutionmore » and precision of the system. A pretreatment radiograph of a phantom containing brachytherapy catheters is acquired and registration between the measurement and treatment planning system (TPS) is performed using implanted fiducial markers. The measured catheter paths immediately prior to treatment were then compared with the plan. During treatment delivery, the position of the {sup 192}Ir source is determined at each dwell position by measuring the exit radiation with the FPD and directly compared to the planned source dwell positions. Results: The registration between the two corresponding sets of fiducial markers in the TPS and radiograph yielded a registration error (residual) of 1.0 mm. The measured catheter paths agreed with the planned catheter paths on average to within 0.5 mm. The source positions measured with the FPD matched the planned source positions for all dwells on average within 0.6 mm (s.d. 0.3, min. 0.1, max. 1.4 mm). Conclusions: We have demonstrated a method for directly comparing the treatment plan with the delivered treatment that can be easily implemented in the clinical workspace. Pretreatment imaging was performed, enabling visualization of the implant before treatment delivery and identification of possible catheter displacement. Treatment delivery verification was performed by measuring the source position as each dwell was delivered. This approach using a FPD for imaging and source tracking provides a noninvasive method of acquiring extensive information for verification in HDR prostate brachytherapy.« less

LDR brachytherapy: can low dose rate hypersensitivity from the "inverse" dose rate effect cause excessive cell killing to peripherial connective tissues and organs?

PubMed

Leonard, B E; Lucas, A C

2009-02-01

Examined here are the possible effects of the "inverse" dose rate effect (IDRE) on low dose rate (LDR) brachytherapy. The hyper-radiosensitivity and induced radioresistance (HRS/IRR) effect benefits cell killing in radiotherapy, and IDRE and HRS/IRR seem to be generated from the same radioprotective mechanisms. We have computed the IDRE excess cell killing experienced in LDR brachytherapy using permanent seed implants. We conclude, firstly, that IDRE is a dose rate-dependent manifestation of HRS/IRR. Secondly, the presence of HRS/IRR or IDRE in a cell species or tissue must be determined by direct dose-response measurements. Thirdly, a reasonable estimate is that 50-80% of human adjoining connective and organ tissues experience IDRE from permanent implanted LDR brachytherapy. If IDRE occurs for tissues at point A for cervical cancer, the excess cell killing will be about a factor of 3.5-4.0 if the initial dose rate is 50-70 cGy h(-1). It is greater for adjacent tissues at lower dose rates and higher for lower initial dose rates at point A. Finally, higher post-treatment complications are observed in LDR brachytherapy, often for unknown reasons. Some of these are probably a result of IDRE excess cell killing. Measurements of IDRE need be performed for connective and adjacent organ tissues, i.e. bladder, rectum, urinary tract and small bowels. The measured dose rate-dependent dose responses should extended to <10 cGy h(-1) and involve multiple patients to detect patient variability. Results may suggest a preference for high dose rate brachytherapy or LDR brachytherapy without permanent retention of the implant seeds (hence the dose rates in peripheral tissues and organs remain above IDRE thresholds).

Automatic seed picking for brachytherapy postimplant validation with 3D CT images.

PubMed

Zhang, Guobin; Sun, Qiyuan; Jiang, Shan; Yang, Zhiyong; Ma, Xiaodong; Jiang, Haisong

2017-11-01

Postimplant validation is an indispensable part in the brachytherapy technique. It provides the necessary feedback to ensure the quality of operation. The ability to pick implanted seed relates directly to the accuracy of validation. To address it, an automatic approach is proposed for picking implanted brachytherapy seeds in 3D CT images. In order to pick seed configuration (location and orientation) efficiently, the approach starts with the segmentation of seed from CT images using a thresholding filter which based on gray-level histogram. Through the process of filtering and denoising, the touching seed and single seed are classified. The true novelty of this approach is found in the application of the canny edge detection and improved concave points matching algorithm to separate touching seeds. Through the computation of image moments, the seed configuration can be determined efficiently. Finally, two different experiments are designed to verify the performance of the proposed approach: (1) physical phantom with 60 model seeds, and (2) patient data with 16 cases. Through assessment of validated results by a medical physicist, the proposed method exhibited promising results. Experiment on phantom demonstrates that the error of seed location and orientation is within ([Formula: see text]) mm and ([Formula: see text])[Formula: see text], respectively. In addition, the most seed location and orientation error is controlled within 0.8 mm and 3.5[Formula: see text] in all cases, respectively. The average process time of seed picking is 8.7 s per 100 seeds. In this paper, an automatic, efficient and robust approach, performed on CT images, is proposed to determine the implanted seed location as well as orientation in a 3D workspace. Through the experiments with phantom and patient data, this approach also successfully exhibits good performance.

In vivo thermoluminescence dosimetry dose verification of transperineal 192Ir high-dose-rate brachytherapy using CT-based planning for the treatment of prostate cancer.

PubMed

Anagnostopoulos, G; Baltas, D; Geretschlaeger, A; Martin, T; Papagiannis, P; Tselis, N; Zamboglou, N

2003-11-15

To evaluate the potential of in vivo thermoluminescence dosimetry to estimate the accuracy of dose delivery in conformal high-dose-rate brachytherapy of prostate cancer. A total of 50 LiF, TLD-100 cylindrical rods were calibrated in the dose range of interest and used as a batch for all fractions. Fourteen dosimeters for every treatment fraction were loaded in a plastic 4F catheter that was fixed in either one of the 6F needles implanted for treatment purposes or in an extra needle implanted after consulting with the patient. The 6F needles were placed either close to the urethra or in the vicinity of the median posterior wall of the prostate. Initial results are presented for 18 treatment fractions in 5 patients and compared to corresponding data calculated using the commercial treatment planning system used for the planning of the treatments based on CT images acquired postimplantation. The maximum observed mean difference between planned and delivered dose within a single treatment fraction was 8.57% +/- 2.61% (root mean square [RMS] errors from 4.03% to 9.73%). Corresponding values obtained after averaging results over all fractions of a patient were 6.88% +/- 4.93% (RMS errors from 4.82% to 7.32%). Experimental results of each fraction corresponding to the same patient point were found to agree within experimental uncertainties. Experimental results indicate that the proposed method is feasible for dose verification purposes and suggest that dose delivery in transperineal high-dose-rate brachytherapy after CT-based planning can be of acceptable accuracy.

The addition of low-dose-rate brachytherapy and androgen-deprivation therapy decreases biochemical failure and prostate cancer death compared with dose-escalated external-beam radiation therapy for high-risk prostate cancer.

PubMed

Shilkrut, Mark; Merrick, Gregory S; McLaughlin, P William; Stenmark, Matthew H; Abu-Isa, Eyad; Vance, Sean M; Sandler, Howard M; Feng, Felix Y; Hamstra, Daniel A

2013-02-01

The objective of this study was to determine whether the addition of low-dose-rate brachytherapy or androgen-deprivation therapy (ADT) improves clinical outcome in patients with high-risk prostate cancer (HiRPCa) who received dose-escalated radiotherapy (RT). Between 1995 and 2010, 958 patients with HiRPCa were treated at Schiffler Cancer Center (n = 484) or at the University of Michigan (n = 474) by receiving either dose-escalated external-beam RT (EBRT) (n = 510; minimum prescription dose, 75 grays [Gy]; median dose, 78 Gy) or combined-modality RT (CMRT) consisting of (103) Pd implants (n = 369) or (125) I implants (n = 79) both with pelvic irradiation (median prescription dose, 45 Gy). The cumulative incidences of biochemical failure (BF) and prostate cancer-specific mortality (PCSM) were estimated by using the Kaplan-Meier method and Fine and Gray regression analysis. The median follow-up was 63.2 months (interquartile range, 35.4-99.0 months), and 250 patients were followed for >8 years. Compared with CMRT, patients who received EBRT had higher prostate-specific antigen levels, higher tumor classification, lower Gleason sum, and more frequent receipt of ADT for a longer duration. The 8-year incidence BF and PCSM among patients who received EBRT was 40% (standard error, 38%-44%) and 13% (standard error, 11%-15%) compared with 14% (standard error, 12%-16%; P < .0001) and 7% (standard error 6%-9%; P = .003) among patients who received CMRT. On multivariate analysis, the hazard ratios (HRs) for BF and PCSM were 0.35 (95% confidence interval [CI], 0.23-0.52; P < .0001) and 0.41 (95% CI, 0.23-0.75; P < .003), favoring CMRT. Increasing duration of ADT predicted decreased BF (P = .04) and PCSM (P = .001), which was greatest with long-term ADT (BF: HR, 0.33; P < .0001; 95% CI, 0.21-0.52; PCSM: HR, 0.30; P = .001; 95% CI, 0.15-0.6) even in the subgroup that received CMRT. In this retrospective comparison, both low-dose-rate brachytherapy boost and ADT were associated with decreased risks of BF and PCSM compared with EBRT. Copyright © 2012 American Cancer Society.

Inorganic scintillation detectors based on Eu-activated phosphors for 192Ir brachytherapy

PubMed Central

Kertzscher, Gustavo; Beddar, Sam

2017-01-01

The availability of real-time treatment verification during high-dose-rate (HDR) brachytherapy is currently limited. Therefore, we studied the luminescence properties of the widely commercially available scintillators using the inorganic materials Eu-activated phosphors Y2O3:Eu, YVO4:Eu, Y2O2S:Eu, and Gd2O2S:Eu to determine whether they could be used to accurately and precisely verify HDR brachytherapy doses in real time. The suitability for HDR brachytherapy of inorganic scintillation detectors (ISDs) based on the 4 Eu-activated phosphors in powder form was determined based on experiments with a 192Ir HDR brachytherapy source. The scintillation intensities of the phosphors were 16 to 134 times greater than that of the commonly used organic plastic scintillator BCF-12. High signal intensities were achieved with an optimized packing density of the phosphor mixture and with a shortened fiber-optic cable. The influence of contaminating Cerenkov and fluorescence light induced in the fiber-optic cable (stem signal) was adequately suppressed by inserting between the fiber-optic cable and the photodetector a 25-nm band-pass filter centered at the emission peak. The spurious photoluminescence signal induced by the stem signal was suppressed by placing a long-pass filter between the scintillation detector volume and the fiber-optic cable. The time-dependent luminescence properties of the phosphors were quantified by measuring the non-constant scintillation during irradiation and the afterglow after the brachytherapy source had retracted. We demonstrated that a mixture of Y2O3:Eu and YVO4:Eu suppressed the time-dependence of the ISDs and that the time-dependence of Y2O2S:Eu and Gd2O2S:Eu introduced large measurement inaccuracies. We conclude that ISDs based on a mixture of Y2O3:Eu and YVO4:Eu are promising candidates for accurate and precise real-time verification technology for HDR BT that is cost effective and straightforward to manufacture. Widespread dissemination of this technology could lead to an improved understanding of error types and frequencies during BT and to improved patient safety during treatment. PMID:28475494

Review of clinical brachytherapy uncertainties: Analysis guidelines of GEC-ESTRO and the AAPM☆

PubMed Central

Kirisits, Christian; Rivard, Mark J.; Baltas, Dimos; Ballester, Facundo; De Brabandere, Marisol; van der Laarse, Rob; Niatsetski, Yury; Papagiannis, Panagiotis; Hellebust, Taran Paulsen; Perez-Calatayud, Jose; Tanderup, Kari; Venselaar, Jack L.M.; Siebert, Frank-André

2014-01-01

Background and purpose A substantial reduction of uncertainties in clinical brachytherapy should result in improved outcome in terms of increased local control and reduced side effects. Types of uncertainties have to be identified, grouped, and quantified. Methods A detailed literature review was performed to identify uncertainty components and their relative importance to the combined overall uncertainty. Results Very few components (e.g., source strength and afterloader timer) are independent of clinical disease site and location of administered dose. While the influence of medium on dose calculation can be substantial for low energy sources or non-deeply seated implants, the influence of medium is of minor importance for high-energy sources in the pelvic region. The level of uncertainties due to target, organ, applicator, and/or source movement in relation to the geometry assumed for treatment planning is highly dependent on fractionation and the level of image guided adaptive treatment. Most studies to date report the results in a manner that allows no direct reproduction and further comparison with other studies. Often, no distinction is made between variations, uncertainties, and errors or mistakes. The literature review facilitated the drafting of recommendations for uniform uncertainty reporting in clinical BT, which are also provided. The recommended comprehensive uncertainty investigations are key to obtain a general impression of uncertainties, and may help to identify elements of the brachytherapy treatment process that need improvement in terms of diminishing their dosimetric uncertainties. It is recommended to present data on the analyzed parameters (distance shifts, volume changes, source or applicator position, etc.), and also their influence on absorbed dose for clinically-relevant dose parameters (e.g., target parameters such as D90 or OAR doses). Publications on brachytherapy should include a statement of total dose uncertainty for the entire treatment course, taking into account the fractionation schedule and level of image guidance for adaptation. Conclusions This report on brachytherapy clinical uncertainties represents a working project developed by the Brachytherapy Physics Quality Assurances System (BRAPHYQS) subcommittee to the Physics Committee within GEC-ESTRO. Further, this report has been reviewed and approved by the American Association of Physicists in Medicine. PMID:24299968

Inorganic scintillation detectors based on Eu-activated phosphors for 192Ir brachytherapy

NASA Astrophysics Data System (ADS)

Kertzscher, Gustavo; Beddar, Sam

2017-06-01

The availability of real-time treatment verification during high-dose-rate (HDR) brachytherapy is currently limited. Therefore, we studied the luminescence properties of the widely commercially available scintillators using the inorganic materials Eu-activated phosphors Y2O3:Eu, YVO4:Eu, Y2O2S:Eu, and Gd2O2S:Eu to determine whether they could be used to accurately and precisely verify HDR brachytherapy doses in real time. The suitability for HDR brachytherapy of inorganic scintillation detectors (ISDs) based on the 4 Eu-activated phosphors in powder form was determined based on experiments with a 192Ir HDR brachytherapy source. The scintillation intensities of the phosphors were 16-134 times greater than that of the commonly used organic plastic scintillator BCF-12. High signal intensities were achieved with an optimized packing density of the phosphor mixture and with a shortened fiber-optic cable. The influence of contaminating Cerenkov and fluorescence light induced in the fiber-optic cable (stem signal) was adequately suppressed by inserting between the fiber-optic cable and the photodetector a 25 nm band-pass filter centered at the emission peak. The spurious photoluminescence signal induced by the stem signal was suppressed by placing a long-pass filter between the scintillation detector volume and the fiber-optic cable. The time-dependent luminescence properties of the phosphors were quantified by measuring the non-constant scintillation during irradiation and the afterglow after the brachytherapy source had retracted. We demonstrated that a mixture of Y2O3:Eu and YVO4:Eu suppressed the time-dependence of the ISDs and that the time-dependence of Y2O2S:Eu and Gd2O2S:Eu introduced large measurement inaccuracies. We conclude that ISDs based on a mixture of Y2O3:Eu and YVO4:Eu are promising candidates for accurate and precise real-time verification technology for HDR BT that is cost effective and straightforward to manufacture. Widespread dissemination of this technology could lead to an improved understanding of error types and frequencies during BT and to improved patient safety during treatment.

Performance assessment of the BEBIG MultiSource® high dose rate brachytherapy treatment unit

NASA Astrophysics Data System (ADS)

Palmer, Antony; Mzenda, Bongile

2009-12-01

A comprehensive system characterisation was performed of the Eckert & Ziegler BEBIG GmbH MultiSource® High Dose Rate (HDR) brachytherapy treatment unit with an 192Ir source. The unit is relatively new to the UK market, with the first installation in the country having been made in the summer of 2009. A detailed commissioning programme was devised and is reported including checks of the fundamental parameters of source positioning, dwell timing, transit doses and absolute dosimetry of the source. Well chamber measurements, autoradiography and video camera analysis techniques were all employed. The absolute dosimetry was verified by the National Physical Laboratory, UK, and compared to a measurement based on a calibration from PTB, Germany, and the supplied source certificate, as well as an independent assessment by a visiting UK centre. The use of the 'Krieger' dosimetry phantom has also been evaluated. Users of the BEBIG HDR system should take care to avoid any significant bend in the transfer tube, as this will lead to positioning errors of the source, of up to 1.0 mm for slight bends, 2.0 mm for moderate bends and 5.0 mm for extreme curvature (depending on applicators and transfer tube used) for the situations reported in this study. The reason for these errors and the potential clinical impact are discussed. Users should also note the methodology employed by the system for correction of transit doses, and that no correction is made for the initial and final transit doses. The results of this investigation found that the uncorrected transit doses lead to small errors in the delivered dose at the first dwell position, of up to 2.5 cGy at 2 cm (5.6 cGy at 1 cm) from a 10 Ci source, but the transit dose correction for other dwells was accurate within 0.2 cGy. The unit has been mechanically reliable, and source positioning accuracy and dwell timing have been reproducible, with overall performance similar to other existing HDR equipment. The unit is capable of high quality brachytherapy treatment delivery, taking the above factors into account.

Quality assurance in MR image guided adaptive brachytherapy for cervical cancer: Final results of the EMBRACE study dummy run.

PubMed

Kirisits, Christian; Federico, Mario; Nkiwane, Karen; Fidarova, Elena; Jürgenliemk-Schulz, Ina; de Leeuw, Astrid; Lindegaard, Jacob; Pötter, Richard; Tanderup, Kari

2015-12-01

Upfront quality assurance (QA) is considered essential when starting a multicenter clinical trial in radiotherapy. Despite the long experience gained for external beam radiotherapy (EBRT) trials, there are only limited audit QA methods for brachytherapy (BT) and none include the specific aspects of image guided adaptive brachytherapy (IGABT). EMBRACE is a prospective multicenter trial aiming to assess the impact of (MRI)-based IGABT in locally advanced cervical cancer. An EMBRACE dummy run was designed to identify sources and magnitude of uncertainties and errors considered important for the evaluation of clinical, and dosimetric parameters and their relation to outcome. Contouring, treatment planning and dose reporting was evaluated and scored with a categorical scale of 1-10. Active feedback to centers was provided to improve protocol compliance and reporting. A second dummy run was required in case of major deviations (score <7) for any item. Overall 27/30 centers passed the dummy run. 16 centers had to repeat the dummy run in order to clarify major inconsistencies to the protocol. The most pronounced variations were related to contouring for both EBRT and BT. Centers with experience in IGABT (>30 cases) had better performance as compared to centers with limited experience. The comprehensive dummy run designed for the EMBRACE trial has been a feasible tool for QA in IGABT of cervix cancer. It should be considered for future IGABT trials and could serve as the basis for continuous quality checks for brachytherapy centers. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Quality Control of High-Dose-Rate Brachytherapy: Treatment Delivery Analysis Using Statistical Process Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Able, Charles M., E-mail: cable@wfubmc.edu; Bright, Megan; Frizzell, Bart

Purpose: Statistical process control (SPC) is a quality control method used to ensure that a process is well controlled and operates with little variation. This study determined whether SPC was a viable technique for evaluating the proper operation of a high-dose-rate (HDR) brachytherapy treatment delivery system. Methods and Materials: A surrogate prostate patient was developed using Vyse ordnance gelatin. A total of 10 metal oxide semiconductor field-effect transistors (MOSFETs) were placed from prostate base to apex. Computed tomography guidance was used to accurately position the first detector in each train at the base. The plan consisted of 12 needles withmore » 129 dwell positions delivering a prescribed peripheral dose of 200 cGy. Sixteen accurate treatment trials were delivered as planned. Subsequently, a number of treatments were delivered with errors introduced, including wrong patient, wrong source calibration, wrong connection sequence, single needle displaced inferiorly 5 mm, and entire implant displaced 2 mm and 4 mm inferiorly. Two process behavior charts (PBC), an individual and a moving range chart, were developed for each dosimeter location. Results: There were 4 false positives resulting from 160 measurements from 16 accurately delivered treatments. For the inaccurately delivered treatments, the PBC indicated that measurements made at the periphery and apex (regions of high-dose gradient) were much more sensitive to treatment delivery errors. All errors introduced were correctly identified by either the individual or the moving range PBC in the apex region. Measurements at the urethra and base were less sensitive to errors. Conclusions: SPC is a viable method for assessing the quality of HDR treatment delivery. Further development is necessary to determine the most effective dose sampling, to ensure reproducible evaluation of treatment delivery accuracy.« less

Optimal matching for prostate brachytherapy seed localization with dimension reduction.

PubMed

Lee, Junghoon; Labat, Christian; Jain, Ameet K; Song, Danny Y; Burdette, Everette C; Fichtinger, Gabor; Prince, Jerry L

2009-01-01

In prostate brachytherapy, x-ray fluoroscopy has been used for intra-operative dosimetry to provide qualitative assessment of implant quality. More recent developments have made possible 3D localization of the implanted radioactive seeds. This is usually modeled as an assignment problem and solved by resolving the correspondence of seeds. It is, however, NP-hard, and the problem is even harder in practice due to the significant number of hidden seeds. In this paper, we propose an algorithm that can find an optimal solution from multiple projection images with hidden seeds. It solves an equivalent problem with reduced dimensional complexity, thus allowing us to find an optimal solution in polynomial time. Simulation results show the robustness of the algorithm. It was validated on 5 phantom and 18 patient datasets, successfully localizing the seeds with detection rate of > or = 97.6% and reconstruction error of < or = 1.2 mm. This is considered to be clinically excellent performance.

SU-F-T-50: Evaluation of Monte Carlo Simulations Performance for Pediatric Brachytherapy Dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatzipapas, C; Kagadis, G; Papadimitroulas, P

Purpose: Pediatric tumors are generally treated with multi-modal procedures. Brachytherapy can be used with pediatric tumors, especially given that in this patient population low toxicity on normal tissues is critical as is the suppression of the probability for late malignancies. Our goal is to validate the GATE toolkit on realistic brachytherapy applications, and evaluate brachytherapy plans on pediatrics for accurate dosimetry on sensitive and critical organs of interest. Methods: The GATE Monte Carlo (MC) toolkit was used. Two High Dose Rate (HDR) 192Ir brachytherapy sources were simulated (Nucletron mHDR-v1 and Varian VS2000), and fully validated using the AAPM and ESTROmore » protocols. A realistic brachytherapy plan was also simulated using the XCAT anthropomorphic computational model .The simulated data were compared to the clinical dose points. Finally, a 14 years old girl with vaginal rhabdomyosarcoma was modelled based on clinical procedures for the calculation of the absorbed dose per organ. Results: The MC simulations resulted in accurate dosimetry in terms of dose rate constant (Λ), radial dose gL(r) and anisotropy function F(r,θ) for both sources.The simulations were executed using ∼1010 number of primaries resulting in statistical uncertainties lower than 2%.The differences between the theoretical values and the simulated ones ranged from 0.01% up to 3.3%, with the largest discrepancy (6%) being observed in the dose rate constant calculation.The simulated DVH using an adult female XCAT model was also compared to a clinical one resulting in differences smaller than 5%. Finally, a realistic pediatric brachytherapy simulation was performed to evaluate the absorbed dose per organ and to calculate DVH with respect to heterogeneities of the human anatomy. Conclusion: GATE is a reliable tool for brachytherapy simulations both for source modeling and for dosimetry in anthropomorphic voxelized models. Our project aims to evaluate a variety of pediatric brachytherapy schemes using a population of pediatric phantoms for several pathological cases. This study is part of a project that has received funding from the European Union Horizon2020 research and innovation programme under the MarieSklodowska-Curiegrantagreement.No691203.The results published in this study reflect only the authors view and the Research Executive Agency (REA) and the European Commission is not responsible for any use that may be madeof the information it contains.« less

Detection and correction of patient movement in prostate brachytherapy seed reconstruction

NASA Astrophysics Data System (ADS)

Lam, Steve T.; Cho, Paul S.; Marks, Robert J., II; Narayanan, Sreeram

2005-05-01

Intraoperative dosimetry of prostate brachytherapy can help optimize the dose distribution and potentially improve clinical outcome. Evaluation of dose distribution during the seed implant procedure requires the knowledge of 3D seed coordinates. Fluoroscopy-based seed localization is a viable option. From three x-ray projections obtained at different gantry angles, 3D seed positions can be determined. However, when local anaesthesia is used for prostate brachytherapy, the patient movement during fluoroscopy image capture becomes a practical problem. If uncorrected, the errors introduced by patient motion between image captures would cause seed mismatches. Subsequently, the seed reconstruction algorithm would either fail to reconstruct or yield erroneous results. We have developed an algorithm that permits detection and correction of patient movement that may occur between fluoroscopy image captures. The patient movement is decomposed into translational shifts along the tabletop and rotation about an axis perpendicular to the tabletop. The property of spatial invariance of the co-planar imaging geometry is used for lateral movement correction. Cranio-caudal movement is corrected by analysing the perspective invariance along the x-ray axis. Rotation is estimated by an iterative method. The method can detect and correct for the range of patient movement commonly seen in the clinical environment. The algorithm has been implemented for routine clinical use as the preprocessing step for seed reconstruction.

A simplified analytical dose calculation algorithm accounting for tissue heterogeneity for low-energy brachytherapy sources.

PubMed

Mashouf, Shahram; Lechtman, Eli; Beaulieu, Luc; Verhaegen, Frank; Keller, Brian M; Ravi, Ananth; Pignol, Jean-Philippe

2013-09-21

The American Association of Physicists in Medicine Task Group No. 43 (AAPM TG-43) formalism is the standard for seeds brachytherapy dose calculation. But for breast seed implants, Monte Carlo simulations reveal large errors due to tissue heterogeneity. Since TG-43 includes several factors to account for source geometry, anisotropy and strength, we propose an additional correction factor, called the inhomogeneity correction factor (ICF), accounting for tissue heterogeneity for Pd-103 brachytherapy. This correction factor is calculated as a function of the media linear attenuation coefficient and mass energy absorption coefficient, and it is independent of the source internal structure. Ultimately the dose in heterogeneous media can be calculated as a product of dose in water as calculated by TG-43 protocol times the ICF. To validate the ICF methodology, dose absorbed in spherical phantoms with large tissue heterogeneities was compared using the TG-43 formalism corrected for heterogeneity versus Monte Carlo simulations. The agreement between Monte Carlo simulations and the ICF method remained within 5% in soft tissues up to several centimeters from a Pd-103 source. Compared to Monte Carlo, the ICF methods can easily be integrated into a clinical treatment planning system and it does not require the detailed internal structure of the source or the photon phase-space.

MRI signal intensity based B-spline nonrigid registration for pre- and intraoperative imaging during prostate brachytherapy.

PubMed

Oguro, Sota; Tokuda, Junichi; Elhawary, Haytham; Haker, Steven; Kikinis, Ron; Tempany, Clare M C; Hata, Nobuhiko

2009-11-01

To apply an intensity-based nonrigid registration algorithm to MRI-guided prostate brachytherapy clinical data and to assess its accuracy. A nonrigid registration of preoperative MRI to intraoperative MRI images was carried out in 16 cases using a Basis-Spline algorithm in a retrospective manner. The registration was assessed qualitatively by experts' visual inspection and quantitatively by measuring the Dice similarity coefficient (DSC) for total gland (TG), central gland (CG), and peripheral zone (PZ), the mutual information (MI) metric, and the fiducial registration error (FRE) between corresponding anatomical landmarks for both the nonrigid and a rigid registration method. All 16 cases were successfully registered in less than 5 min. After the nonrigid registration, DSC values for TG, CG, PZ were 0.91, 0.89, 0.79, respectively, the MI metric was -0.19 +/- 0.07 and FRE presented a value of 2.3 +/- 1.8 mm. All the metrics were significantly better than in the case of rigid registration, as determined by one-sided t-tests. The intensity-based nonrigid registration method using clinical data was demonstrated to be feasible and showed statistically improved metrics when compare to only rigid registration. The method is a valuable tool to integrate pre- and intraoperative images for brachytherapy.

In vivo measurements for high dose rate brachytherapy with optically stimulated luminescent dosimeters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Renu; Jursinic, Paul A.

2013-07-15

Purpose: To show the feasibility of clinical implementation of OSLDs for high dose-rate (HDR) in vivo dosimetry for gynecological and breast patients. To discuss how the OSLDs were characterized for an Ir-192 source, taking into account low gamma energy and high dose gradients. To describe differences caused by the dose calculation formalism of treatment planning systems.Methods: OSLD irradiations were made using the GammaMedplus iX Ir-192 HDR, Varian Medical Systems, Milpitas, CA. BrachyVision versions 8.9 and 10.0, Varian Medical Systems, Milpitas, CA, were used for calculations. Version 8.9 used the TG-43 algorithm and version 10.0 used the Acuros algorithm. The OSLDsmore » (InLight Nanodots) were characterized for Ir-192. Various phantoms were created to assess calculated and measured doses and the angular dependence and self-absorption of the Nanodots. Following successful phantom measurements, patient measurements for gynecological patients and breast cancer patients were made and compared to calculated doses.Results: The OSLD sensitivity to Ir-192 compared to 6 MV is between 1.10 and 1.25, is unique to each detector, and changes with accumulated dose. The measured doses were compared to those predicted by the treatment planning system and found to be in agreement for the gynecological patients to within measurement uncertainty. The range of differences between the measured and Acuros calculated doses was -10%-14%. For the breast patients, there was a discrepancy of -4.4% to +6.5% between the measured and calculated doses at the skin surface when the Acuros algorithm was used. These differences were within experimental uncertainty due to (random) error in the location of the detector with respect to the treatment catheter.Conclusions: OSLDs can be successfully used for HDR in vivo dosimetry. However, for the measurements to be meaningful one must account for the angular dependence, volume-averaging, and the greater sensitivity to Ir-192 gamma rays than to 6 MV x-rays if 6 MV x-rays were used for OSLD calibration. The limitations of the treatment planning algorithm must be understood, especially for surface dose measurements. Use of in vivo dosimetry for HDR brachytherapy treatments is feasible and has the potential to detect and prevent gross errors. In vivo HDR brachytherapy should be included as part of the QA for a HDR brachytherapy program.« less

Dosimetry Modeling for Focal Low-Dose-Rate Prostate Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Qaisieh, Bashar; Mason, Josh, E-mail: joshua.mason@nhs.net; Bownes, Peter

2015-07-15

Purpose: Focal brachytherapy targeted to an individual lesion(s) within the prostate may reduce side effects experienced with whole-gland brachytherapy. The outcomes of a consensus meeting on focal prostate brachytherapy were used to investigate optimal dosimetry of focal low-dose-rate (LDR) prostate brachytherapy targeted using multiparametric magnetic resonance imaging (mp-MRI) and transperineal template prostate mapping (TPM) biopsy, including the effects of random and systematic seed displacements and interseed attenuation (ISA). Methods and Materials: Nine patients were selected according to clinical characteristics and concordance of TPM and mp-MRI. Retrospectively, 3 treatment plans were analyzed for each case: whole-gland (WG), hemi-gland (hemi), and ultra-focalmore » (UF) plans, with 145-Gy prescription dose and identical dose constraints for each plan. Plan robustness to seed displacement and ISA were assessed using Monte Carlo simulations. Results: WG plans used a mean 28 needles and 81 seeds, hemi plans used 17 needles and 56 seeds, and UF plans used 12 needles and 25 seeds. Mean D90 (minimum dose received by 90% of the target) and V100 (percentage of the target that receives 100% dose) values were 181.3 Gy and 99.8% for the prostate in WG plans, 195.7 Gy and 97.8% for the hemi-prostate in hemi plans, and 218.3 Gy and 99.8% for the focal target in UF plans. Mean urethra D10 was 205.9 Gy, 191.4 Gy, and 92.4 Gy in WG, hemi, and UF plans, respectively. Mean rectum D2 cm{sup 3} was 107.5 Gy, 77.0 Gy, and 42.7 Gy in WG, hemi, and UF plans, respectively. Focal plans were more sensitive to seed displacement errors: random shifts with a standard deviation of 4 mm reduced mean target D90 by 14.0%, 20.5%, and 32.0% for WG, hemi, and UF plans, respectively. ISA has a similar impact on dose-volume histogram parameters for all plan types. Conclusions: Treatment planning for focal LDR brachytherapy is feasible. Dose constraints are easily met with a notable reduction to organs at risk. Treating smaller targets makes seed positioning more critical.« less

The influence of smoking on radiation-induced bystander signal production in esophageal cancer patients.

PubMed

Hanu, C; Timotin, E; Wong, R; Sur, R K; Hayward, J E; Seymour, C B; Mothersill, C E

2016-05-01

The relevance of radiation-induced bystander effects in humans is unclear. Much of the existing data relate to cell lines but the effect of bystander signals in complex human tissues is unclear. A phase II clinical study was untaken, where blood sera from 60 patients along with 15 cancer-free volunteers were used to detect whether measurable bystander factor(s) could be found in the blood following high dose rate (HDR) brachytherapy. Overall, there was no significant change in bystander signal production (measured in a human keratinocyte reporter system) before and after one treatment fraction of HDR brachytherapy (p>0.05). Further assessment of patient characteristics and environmental modifiable factors including smoking were also analyzed. Similar to previously published data, samples taken from smokers produced weaker signals compared to non-smokers (p<0.05). Although the number of non-smoking subjects was low, there was a clear decrease in cloning efficiency observed in keratinocyte cultures for these patients that requires further study. This study found that samples taken from smokers do not produce bystander signals, whereas samples taken from non-smokers can produce such signals following HDR brachytherapy. These findings highlight the importance of studying the interactions of multiple stressors including environmental modifiers with radiation, since some factors such as smoking may elicit protection in tumor cells which could counteract the effectiveness of radiation therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

A novel method for accurate needle-tip identification in trans-rectal ultrasound-based high-dose-rate prostate brachytherapy.

PubMed

Zheng, Dandan; Todor, Dorin A

2011-01-01

In real-time trans-rectal ultrasound (TRUS)-based high-dose-rate prostate brachytherapy, the accurate identification of needle-tip position is critical for treatment planning and delivery. Currently, needle-tip identification on ultrasound images can be subject to large uncertainty and errors because of ultrasound image quality and imaging artifacts. To address this problem, we developed a method based on physical measurements with simple and practical implementation to improve the accuracy and robustness of needle-tip identification. Our method uses measurements of the residual needle length and an off-line pre-established coordinate transformation factor, to calculate the needle-tip position on the TRUS images. The transformation factor was established through a one-time systematic set of measurements of the probe and template holder positions, applicable to all patients. To compare the accuracy and robustness of the proposed method and the conventional method (ultrasound detection), based on the gold-standard X-ray fluoroscopy, extensive measurements were conducted in water and gel phantoms. In water phantom, our method showed an average tip-detection accuracy of 0.7 mm compared with 1.6 mm of the conventional method. In gel phantom (more realistic and tissue-like), our method maintained its level of accuracy while the uncertainty of the conventional method was 3.4mm on average with maximum values of over 10mm because of imaging artifacts. A novel method based on simple physical measurements was developed to accurately detect the needle-tip position for TRUS-based high-dose-rate prostate brachytherapy. The method demonstrated much improved accuracy and robustness over the conventional method. Copyright © 2011 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Clinical application and validation of an iterative forward projection matching algorithm for permanent brachytherapy seed localization from conebeam-CT x-ray projections.

PubMed

Pokhrel, Damodar; Murphy, Martin J; Todor, Dorin A; Weiss, Elisabeth; Williamson, Jeffrey F

2010-09-01

To experimentally validate a new algorithm for reconstructing the 3D positions of implanted brachytherapy seeds from postoperatively acquired 2D conebeam-CT (CBCT) projection images. The iterative forward projection matching (IFPM) algorithm finds the 3D seed geometry that minimizes the sum of the squared intensity differences between computed projections of an initial estimate of the seed configuration and radiographic projections of the implant. In-house machined phantoms, containing arrays of 12 and 72 seeds, respectively, are used to validate this method. Also, four 103Pd postimplant patients are scanned using an ACUITY digital simulator. Three to ten x-ray images are selected from the CBCT projection set and processed to create binary seed-only images. To quantify IFPM accuracy, the reconstructed seed positions are forward projected and overlaid on the measured seed images to find the nearest-neighbor distance between measured and computed seed positions for each image pair. Also, the estimated 3D seed coordinates are compared to known seed positions in the phantom and clinically obtained VariSeed planning coordinates for the patient data. For the phantom study, seed localization error is (0.58 +/- 0.33) mm. For all four patient cases, the mean registration error is better than 1 mm while compared against the measured seed projections. IFPM converges in 20-28 iterations, with a computation time of about 1.9-2.8 min/ iteration on a 1 GHz processor. The IFPM algorithm avoids the need to match corresponding seeds in each projection as required by standard back-projection methods. The authors' results demonstrate approximately 1 mm accuracy in reconstructing the 3D positions of brachytherapy seeds from the measured 2D projections. This algorithm also successfully localizes overlapping clustered and highly migrated seeds in the implant.

Clinical application and validation of an iterative forward projection matching algorithm for permanent brachytherapy seed localization from conebeam-CT x-ray projections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pokhrel, Damodar; Murphy, Martin J.; Todor, Dorin A.

2010-09-15

Purpose: To experimentally validate a new algorithm for reconstructing the 3D positions of implanted brachytherapy seeds from postoperatively acquired 2D conebeam-CT (CBCT) projection images. Methods: The iterative forward projection matching (IFPM) algorithm finds the 3D seed geometry that minimizes the sum of the squared intensity differences between computed projections of an initial estimate of the seed configuration and radiographic projections of the implant. In-house machined phantoms, containing arrays of 12 and 72 seeds, respectively, are used to validate this method. Also, four {sup 103}Pd postimplant patients are scanned using an ACUITY digital simulator. Three to ten x-ray images are selectedmore » from the CBCT projection set and processed to create binary seed-only images. To quantify IFPM accuracy, the reconstructed seed positions are forward projected and overlaid on the measured seed images to find the nearest-neighbor distance between measured and computed seed positions for each image pair. Also, the estimated 3D seed coordinates are compared to known seed positions in the phantom and clinically obtained VariSeed planning coordinates for the patient data. Results: For the phantom study, seed localization error is (0.58{+-}0.33) mm. For all four patient cases, the mean registration error is better than 1 mm while compared against the measured seed projections. IFPM converges in 20-28 iterations, with a computation time of about 1.9-2.8 min/iteration on a 1 GHz processor. Conclusions: The IFPM algorithm avoids the need to match corresponding seeds in each projection as required by standard back-projection methods. The authors' results demonstrate {approx}1 mm accuracy in reconstructing the 3D positions of brachytherapy seeds from the measured 2D projections. This algorithm also successfully localizes overlapping clustered and highly migrated seeds in the implant.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Otani, Y; Sumida, I; Yagi, M

Purpose: Brachytherapy has multiple manual procedures which are prone to human error, especially during the connection process of the treatment device to applicator. This is when considerable attention is required. In this study, we propose a new connection verification device concept. Methods: The system is composed of a ring magnet (anisotropic ferrite : magfine Inc), hole device (A1324LUA-T : Allegro MicroSystems Phil Inc) and an in-house check cable, which is made from magnetic material (Figure1). The magnetic field distribution is affected by the check cable position and any magnetic field variation is detected by the hole device. This system frequencymore » is 20Hz and the average of 4 signals was used as hole device value to reduce noise. Results: The value of the hole device is altered, depending on the location of the check cable. The resolution of the check cable position is 5mm and 10mm, around a 10mm region from the hole device and over 10mm, respectively. There was a reduction in sensitivity of the hole device, in our test, which was linked to the distance of the hole device from the check cable. Conclusion: We demonstrated a new concept of connection verification in a brachytherapy. This system has the possibility to detect an incorrect connection. Moreover, the system is capable of self-optimization, such as determining the number of hole device and the magnet strength.Acknowledgement:This work was supported by JSPS Core -to-Core program Number 23003 and KAKENHI Grant Number 26860401. This work was supported by JSPS Core-to-Core program Number 23003 and KAKENHI Grant Number 26860401.« less

Real-time catheter tracking for high-dose-rate prostate brachytherapy using an electromagnetic 3D-guidance device: A preliminary performance study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou Jun; Sebastian, Evelyn; Mangona, Victor

2013-02-15

Purpose: In order to increase the accuracy and speed of catheter reconstruction in a high-dose-rate (HDR) prostate implant procedure, an automatic tracking system has been developed using an electromagnetic (EM) device (trakSTAR, Ascension Technology, VT). The performance of the system, including the accuracy and noise level with various tracking parameters and conditions, were investigated. Methods: A direct current (dc) EM transmitter (midrange model) and a sensor with diameter of 1.3 mm (Model 130) were used in the trakSTAR system for tracking catheter position during HDR prostate brachytherapy. Localization accuracy was assessed under both static and dynamic analyses conditions. For themore » static analysis, a calibration phantom was used to investigate error dependency on operating room (OR) table height (bottom vs midposition vs top), sensor position (distal tip of catheter vs connector end of catheter), direction [left-right (LR) vs anterior-posterior (AP) vs superior-inferior (SI)], sampling frequency (40 vs 80 vs 120 Hz), and interference from OR equipment (present vs absent). The mean and standard deviation of the localization offset in each direction and the corresponding error vectors were calculated. For dynamic analysis, the paths of five straight catheters were tracked to study the effects of directions, sampling frequency, and interference of EM field. Statistical analysis was conducted to compare the results in different configurations. Results: When interference was present in the static analysis, the error vectors were significantly higher at the top table position (3.3 {+-} 1.3 vs 1.8 {+-} 0.9 mm at bottom and 1.7 {+-} 1.0 mm at middle, p < 0.001), at catheter end position (3.1 {+-} 1.1 vs 1.4 {+-} 0.7 mm at the tip position, p < 0.001), and at 40 Hz sampling frequency (2.6 {+-} 1.1 vs 2.4 {+-} 1.5 mm at 80 Hz and 1.8 {+-} 1.1 at 160 Hz, p < 0.001). So did the mean offset errors in the LR direction (-1.7 {+-} 1.4 vs 0.4 {+-} 0.5 mm in AP and 0.8 {+-} 0.8 mm in SI directions, p < 0.001). The error vectors were significantly higher with surrounding interference (2.2 {+-} 1.3 mm) vs without interference (1.0 {+-} 0.7 mm, p < 0.001). An accuracy of 1.6 {+-} 0.2 mm can be reached when using optimum configuration (160 Hz at middle table position). When interference was present in the dynamic tracking, the mean tracking errors in LR direction (1.4 {+-} 0.5 mm) was significantly higher than that in AP direction (0.3 {+-} 0.2 mm, p < 0.001). So did the mean vector errors at 40 Hz (2.1 {+-} 0.2 mm vs 1.3 {+-} 0.2 mm at 80 Hz and 0.9 {+-} 0.2 mm at 160 Hz, p < 0.05). However, when interference was absent, they were comparable in the both directions and at all sampling frequencies. An accuracy of 0.9 {+-} 0.2 mm was obtained for the dynamic tracking when using optimum configuration. Conclusions: The performance of an EM tracking system depends highly on the system configuration and surrounding environment. The accuracy of EM tracking for catheter reconstruction in a prostate HDR brachytherapy procedure can be improved by reducing interference from surrounding equipment, decreasing distance from transmitter to tracking area, and choosing appropriated sampling frequency. A calibration scheme is needed to further reduce the tracking error when the interference is high.« less

MRI Signal Intensity Based B-Spline Nonrigid Registration for Pre- and Intraoperative Imaging During Prostate Brachytherapy

PubMed Central

Oguro, Sota; Tokuda, Junichi; Elhawary, Haytham; Haker, Steven; Kikinis, Ron; Tempany, Clare M.C.; Hata, Nobuhiko

2009-01-01

Purpose To apply an intensity-based nonrigid registration algorithm to MRI-guided prostate brachytherapy clinical data and to assess its accuracy. Materials and Methods A nonrigid registration of preoperative MRI to intraoperative MRI images was carried out in 16 cases using a Basis-Spline algorithm in a retrospective manner. The registration was assessed qualitatively by experts’ visual inspection and quantitatively by measuring the Dice similarity coefficient (DSC) for total gland (TG), central gland (CG), and peripheral zone (PZ), the mutual information (MI) metric, and the fiducial registration error (FRE) between corresponding anatomical landmarks for both the nonrigid and a rigid registration method. Results All 16 cases were successfully registered in less than 5 min. After the nonrigid registration, DSC values for TG, CG, PZ were 0.91, 0.89, 0.79, respectively, the MI metric was −0.19 ± 0.07 and FRE presented a value of 2.3 ± 1.8 mm. All the metrics were significantly better than in the case of rigid registration, as determined by one-sided t-tests. Conclusion The intensity-based nonrigid registration method using clinical data was demonstrated to be feasible and showed statistically improved metrics when compare to only rigid registration. The method is a valuable tool to integrate pre- and intraoperative images for brachytherapy. PMID:19856437

Preliminary report on the effect of brachytherapy on expression of p53, bc1-2 and apoptosis in squamous cell carcinoma of the oesophagus.

PubMed

Sur, Monalisa; Sur, Ranjan K; Cooper, Kum; Bizos, Damon

2003-02-01

Pre-brachytherapy biopsies and post-brachytherapy oesophagectomy specimens of 10 patients with early squamous cell carcinoma of the middle third of the oesophagus were examined for the expression of p53, bcl-2 and apoptosis using immunohistochemical markers. There was no expression of p53 in one patient in both pre- and post-brachytherapy specimens. In 8 patients, p53 staining was strongly positive (3+) with approximately 50% or more cells, and with diffuse and no specific pattern in the pre-brachytherapy biopsies. The tumour areas of the post-brachytherapy specimens of this group showed strong 3+ positivity with p53 (10-50% positive cell count), with the pattern being focal and peripheral in the tumour islands. The centre of the tumour islands showed necrosis and/or keratinisation. In one patient, the pre-brachytherapy biopsy showed expression of p53 while the post-brachytherapy specimen was negative. bcl-2 expression in both pre- and post-brachytherapy was equivocal and inconclusive in both the pre- and post-brachytherapy specimens. Apoptosis was negative in all the pre- and post-brachytherapy tissue sections in the presence of positive controls. Brachytherapy does not cause cell death by apoptosis but by necrosis and maturation of the cells into better differentiated cells, which is caused by OH free radical, and induction of the keratin gene respectively. It is possible that brachytherapy may cause destruction of cells containing wild-type p53, while mutant p53 in cells located at the tumour periphery escape the effect of brachytherapy. This may be responsible for the high incidence of local recurrence and distant metastasis in oesophageal cancer treated with radiotherapy. There is no effect of brachytherapy on bcl-2 expression in oesophageal cancer.

Toward a 3D transrectal ultrasound system for verification of needle placement during high-dose-rate interstitial gynecologic brachytherapy.

PubMed

Rodgers, Jessica Robin; Surry, Kathleen; Leung, Eric; D'Souza, David; Fenster, Aaron

2017-05-01

Treatment for gynecologic cancers, such as cervical, recurrent endometrial, and vaginal malignancies, commonly includes external-beam radiation and brachytherapy. In high-dose-rate (HDR) interstitial gynecologic brachytherapy, radiation treatment is delivered via hollow needles that are typically inserted through a template on the perineum with a cylinder placed in the vagina for stability. Despite the need for precise needle placement to minimize complications and provide optimal treatment, there is no standard intra-operative image-guidance for this procedure. While some image-guidance techniques have been proposed, including magnetic resonance (MR) imaging, X-ray computed tomography (CT), and two-dimensional (2D) transrectal ultrasound (TRUS), these techniques have not been widely adopted. In order to provide intra-operative needle visualization and localization during interstitial brachytherapy, we have developed a three-dimensional (3D) TRUS system. This study describes the 3D TRUS system and reports on the system validation and results from a proof-of-concept patient study. To obtain a 3D TRUS image, the system rotates a conventional 2D endocavity transducer through 170 degrees in 12 s, reconstructing the 2D frames into a 3D image in real-time. The geometry of the reconstruction was validated using two geometric phantoms to ensure the accuracy of the linear measurements in each of the image coordinate directions and the volumetric accuracy of the system. An agar phantom including vaginal and rectal canals, as well as a model uterus and tumor, was designed and used to test the visualization and localization of the interstitial needles under idealized conditions by comparing the needles' positions between the 3D TRUS scan and a registered MR image. Five patients undergoing HDR interstitial gynecologic brachytherapy were imaged using the 3D TRUS system following the insertion of all needles. This image was manually, rigidly registered to the clinical postinsertion CT scan based on the vaginal cylinder of the needle template. The positions of the tips and the trajectory of the needle paths were compared between the modalities. The observed geometric errors of the system were ≤ 0.3 mm in each of the three coordinate planes of the 3D US image and the mean measured volumetric error was 0.10 cm 3 . In the phantom study, the mean needle tip difference was 1.54 ± 0.71 mm and the mean trajectory difference was 0.94 ± 0.89 degrees (n = 14). In the in vivo study, a total of 73 needles were placed, of which 88% of needles were visible and 79% of tips were identifiable in the 3D TRUS images. Six of the nine needles that were not visible were due to shadowing artifacts created by the presence of the vaginal cylinder of the needle template. The mean distance between corresponding needle tips in the two modalities was 3.82 ± 1.86 mm and the mean trajectory difference was 3.04 ± 1.63 degrees for the five patients. In this proof-of-concept study, the 3D TRUS system allowed for localization of needles not obscured by shadowing artifacts, providing a method for visualizing needles intra-operatively during HDR interstitial brachytherapy of gynecologic cancers and providing the potential for 3D image-guidance. © 2017 American Association of Physicists in Medicine.

Palliative radiation therapy practice for advanced esophageal carcinoma in Africa.

PubMed

Sharma, V; Gaye, P M; Wahab, S A; Ndlovu, N; Ngoma, T; Vanderpuye, V; Sowuhami, A; Dawotola, D A; Kigula-Mugambe, J; Jeremic, B

2010-04-01

While numerous surveys of pattern of practices of palliative radiotherapy (RT) in advanced esophageal cancers have been published in developed countries, there is no such survey in African countries. During and after a regional training course by the International Atomic Energy Agency (IAEA) in palliative cancer care, a questionnaire was distributed to African RT centers to gather information about infrastructure and human resources available, and the pattern of practice of palliative RT for esophageal cancers. Twenty-four of the 35 centers (60%) completed the questionnaire. Twenty out of 23 (87%) centers treat patients with esophageal cancer presenting with dysphagia using external beam RT (16 centers external beam RT alone and 4 centers also use brachytherapy as a boost). Twelve (60%) centers prescribe RT doses of 30 Gy in 10 fractions and 2 centers 20 Gy in 5 fractions. Eighteen centers (78%) have low dose rate (LDR) brachytherapy, and 9 (39%) centers have high dose rate (HDR) brachytherapy. One center only used HDR brachytherapy alone to a dose of 16 Gy in 2 fractions over 8 days. RT remains a major component of treatment of patients with esophageal cancers in African countries. Still, there is a great variety among centers in both indications for RT and its characteristics for a treatment indication.

A fully actuated robotic assistant for MRI-guided prostate biopsy and brachytherapy

NASA Astrophysics Data System (ADS)

Li, Gang; Su, Hao; Shang, Weijian; Tokuda, Junichi; Hata, Nobuhiko; Tempany, Clare M.; Fischer, Gregory S.

2013-03-01

Intra-operative medical imaging enables incorporation of human experience and intelligence in a controlled, closed-loop fashion. Magnetic resonance imaging (MRI) is an ideal modality for surgical guidance of diagnostic and therapeutic procedures, with its ability to perform high resolution, real-time, high soft tissue contrast imaging without ionizing radiation. However, for most current image-guided approaches only static pre-operative images are accessible for guidance, which are unable to provide updated information during a surgical procedure. The high magnetic field, electrical interference, and limited access of closed-bore MRI render great challenges to developing robotic systems that can perform inside a diagnostic high-field MRI while obtaining interactively updated MR images. To overcome these limitations, we are developing a piezoelectrically actuated robotic assistant for actuated percutaneous prostate interventions under real-time MRI guidance. Utilizing a modular design, the system enables coherent and straight forward workflow for various percutaneous interventions, including prostate biopsy sampling and brachytherapy seed placement, using various needle driver configurations. The unified workflow compromises: 1) system hardware and software initialization, 2) fiducial frame registration, 3) target selection and motion planning, 4) moving to the target and performing the intervention (e.g. taking a biopsy sample) under live imaging, and 5) visualization and verification. Phantom experiments of prostate biopsy and brachytherapy were executed under MRI-guidance to evaluate the feasibility of the workflow. The robot successfully performed fully actuated biopsy sampling and delivery of simulated brachytherapy seeds under live MR imaging, as well as precise delivery of a prostate brachytherapy seed distribution with an RMS accuracy of 0.98mm.

Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system.

PubMed

Poulin, Eric; Racine, Emmanuel; Binnekamp, Dirk; Beaulieu, Luc

2015-03-01

In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora(®) Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators.

SU-F-BRA-01: A Procedure for the Fast Semi-Automatic Localization of Catheters Using An Electromagnetic Tracker (EMT) for Image-Guided Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Damato, A; Viswanathan, A; Cormack, R

2015-06-15

Purpose: To evaluate the feasibility of brachytherapy catheter localization through use of an EMT and 3D image set. Methods: A 15-catheter phantom mimicking an interstitial implantation was built and CT-scanned. Baseline catheter reconstruction was performed manually. An EMT was used to acquire the catheter coordinates in the EMT frame of reference. N user-identified catheter tips, without catheter number associations, were used to establish registration with the CT frame of reference. Two algorithms were investigated: brute-force registration (BFR), in which all possible permutation of N identified tips with the EMT tips were evaluated; and signature-based registration (SBR), in which a distancemore » matrix was used to generate a list of matching signatures describing possible N-point matches with the registration points. Digitization error (average of the distance between corresponding EMT and baseline dwell positions; average, standard deviation, and worst-case scenario over all possible registration-point selections) and algorithm inefficiency (maximum number of rigid registrations required to find the matching fusion for all possible selections of registration points) were calculated. Results: Digitization errors on average <2 mm were observed for N ≥5, with standard deviation <2 mm for N ≥6, and worst-case scenario error <2 mm for N ≥11. Algorithm inefficiencies were: N = 5, 32,760 (BFR) and 9900 (SBR); N = 6, 360,360 (BFR) and 21,660 (SBR); N = 11, 5.45*1010 (BFR) and 12 (SBR). Conclusion: A procedure was proposed for catheter reconstruction using EMT and only requiring user identification of catheter tips without catheter localization. Digitization errors <2 mm were observed on average with 5 or more registration points, and in any scenario with 11 or more points. Inefficiency for N = 11 was 9 orders of magnitude lower for SBR than for BFR. Funding: Kaye Family Award.« less

Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc, E-mail: Luc.Beaulieu@phy.ulaval.ca

2015-03-15

Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora{sup ®} Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position andmore » orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators.« less

A survey of current clinical practice in permanent and temporary prostate brachytherapy: 2010 update.

PubMed

Buyyounouski, Mark K; Davis, Brian J; Prestidge, Bradley R; Shanahan, Thomas G; Stock, Richard G; Grimm, Peter D; Demanes, D Jeffrey; Zaider, Marco; Horwitz, Eric M

2012-01-01

To help establish patterns of care and standards of care of interstitial permanent low-dose-rate (LDR) and temporary high-dose-rate brachytherapy for prostate cancer and to compare the results with a similar 1998 American Brachytherapy Society (ABS) survey. A comprehensive questionnaire intended to survey specific details of current clinical brachytherapy practice was provided to the participants of the seventh ABS Prostate Brachytherapy School. Responses were tabulated and descriptive statistics are reported. Sixty-five brachytherapy practitioners responded to the survey. Eighty-nine percent (89%) of respondents performed LDR and 49% perform high-dose-rate brachytherapy. The median number of years of experience for LDR brachytherapists increased from 5 to 10 years over the course of the 12 years since the preceding survey. Compared with the first ABS, a smaller proportion of respondents received formal brachytherapy residency training (43% vs. 56%) or formal "hands-on" brachytherapy training (15% vs. 63%). There has been a marked decline in the utilization of the Mick applicator (Mick Radio-Nuclear Instruments, Inc., Mount Vernon, NY, USA) (60% vs. 28%) and an increase in the use of stranded seeds (40% vs. 11%). Compliance with postimplant dosimetry was higher in the 2010 survey. This survey does suggest an evolution in the practice of LDR brachytherapy since 1998 and aids in identifying aspects that require further progress or investigation. ABS guidelines and other practice recommendations appear to impact the practice of brachytherapy. Copyright © 2012 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Underuse of brachytherapy for the treatment of dysphagia owing to esophageal cancer. An Italian survey.

PubMed

Fuccio, Lorenzo; Guido, Alessandra; Hassan, Cesare; Frazzoni, Leonardo; Arcelli, Alessandra; Farioli, Andrea; Giaccherini, Lucia; Galuppi, Andrea; Mandolesi, Daniele; Cellini, Francesco; Mantello, Giovanna; Macchia, Gabriella; de Bortoli, Nicola; Repici, Alessandro; Valentini, Vincenzo; Bazzoli, Franco; Morganti, Alessio Giuseppe

2016-10-01

International guidelines strongly recommend brachytherapy as valid alternative or in addition to stenting in patients with dysphagia owing to esophageal cancer. However, for not well understood reasons, brachytherapy is definitively underused for the palliative treatment of malignant dysphagia. Aim of the current survey was to investigate the use of brachytherapy for the treatment of malignant dysphagia in Italy. A structured questionnaire was submitted to the 1510 members of the Italian Association of Radiation Oncologists (AIRO). These members refer to 177 centres of radiotherapy across Italy and in 68 (38.4%) of them brachytherapy is routinely performed. Of the 1510 invited members, 178 completed the survey (11.7%). The answers provided by the 178 participants allowed to get information on 40 out of 68 brachytherapy centres (58.8%). Seven out of 40 (17.5%) centres perform brachytherapy of the oesophagus, in 3 out of 40 (7.5%) centres brachytherapy represents the first line of treatment. The main reason why brachytherapy is not routinely performed is the lack of experience. Despite the strong recommendations of the international guidelines and the wide diffusion of brachytherapy centres across Italy, only very few of them routinely considered brachytherapy for the treatment of dysphagia due to esophageal cancer. Copyright © 2016 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Dose verification of eye plaque brachytherapy using spectroscopic dosimetry.

PubMed

Jarema, T; Cutajar, D; Weaver, M; Petasecca, M; Lerch, M; Kejda, A; Rosenfeld, A

2016-09-01

Eye plaque brachytherapy has been developed and refined for the last 80 years, demonstrating effective results in the treatment of ocular malignancies. Current dosimetry techniques for eye plaque brachytherapy (such as TLD- and film-based techniques) are time consuming and cannot be used prior to treatment in a sterile environment. The measurement of the expected dose distribution within the eye, prior to insertion within the clinical setting, would be advantageous, as any errors in source loading will lead to an erroneous dose distribution and inferior treatment outcomes. This study investigated the use of spectroscopic dosimetry techniques for real-time quality assurance of I-125 based eye plaques, immediately prior to insertion. A silicon detector based probe, operating in spectroscopy mode was constructed, containing a small (1 mm(3)) silicon detector, mounted within a ceramic holder, all encapsulated within a rubber sheath to prevent water infiltration of the electronics. Preliminary tests of the prototype demonstrated that the depth dose distribution through the central axis of an I-125 based eye plaque may be determined from AAPM Task Group 43 recommendations to a deviation of 6 % at 3 mm depth, 7 % at 5 mm depth, 1 % at 10 mm depth and 13 % at 20 mm depth, with the deviations attributed to the construction of the probe. A new probe design aims to reduce these discrepancies, however the concept of spectroscopic dosimetry shows great promise for use in eye plaque quality assurance in the clinical setting.

Collision-kerma conversion between dose-to-tissue and dose-to-water by photon energy-fluence corrections in low-energy brachytherapy

NASA Astrophysics Data System (ADS)

Giménez-Alventosa, Vicent; Antunes, Paula C. G.; Vijande, Javier; Ballester, Facundo; Pérez-Calatayud, José; Andreo, Pedro

2017-01-01

The AAPM TG-43 brachytherapy dosimetry formalism, introduced in 1995, has become a standard for brachytherapy dosimetry worldwide; it implicitly assumes that charged-particle equilibrium (CPE) exists for the determination of absorbed dose to water at different locations, except in the vicinity of the source capsule. Subsequent dosimetry developments, based on Monte Carlo calculations or analytical solutions of transport equations, do not rely on the CPE assumption and determine directly the dose to different tissues. At the time of relating dose to tissue and dose to water, or vice versa, it is usually assumed that the photon fluence in water and in tissues are practically identical, so that the absorbed dose in the two media can be related by their ratio of mass energy-absorption coefficients. In this work, an efficient way to correlate absorbed dose to water and absorbed dose to tissue in brachytherapy calculations at clinically relevant distances for low-energy photon emitting seeds is proposed. A correction is introduced that is based on the ratio of the water-to-tissue photon energy-fluences. State-of-the art Monte Carlo calculations are used to score photon fluence differential in energy in water and in various human tissues (muscle, adipose and bone), which in all cases include a realistic modelling of low-energy brachytherapy sources in order to benchmark the formalism proposed. The energy-fluence based corrections given in this work are able to correlate absorbed dose to tissue and absorbed dose to water with an accuracy better than 0.5% in the most critical cases (e.g. bone tissue).

Collision-kerma conversion between dose-to-tissue and dose-to-water by photon energy-fluence corrections in low-energy brachytherapy.

PubMed

Giménez-Alventosa, Vicent; Antunes, Paula C G; Vijande, Javier; Ballester, Facundo; Pérez-Calatayud, José; Andreo, Pedro

2017-01-07

The AAPM TG-43 brachytherapy dosimetry formalism, introduced in 1995, has become a standard for brachytherapy dosimetry worldwide; it implicitly assumes that charged-particle equilibrium (CPE) exists for the determination of absorbed dose to water at different locations, except in the vicinity of the source capsule. Subsequent dosimetry developments, based on Monte Carlo calculations or analytical solutions of transport equations, do not rely on the CPE assumption and determine directly the dose to different tissues. At the time of relating dose to tissue and dose to water, or vice versa, it is usually assumed that the photon fluence in water and in tissues are practically identical, so that the absorbed dose in the two media can be related by their ratio of mass energy-absorption coefficients. In this work, an efficient way to correlate absorbed dose to water and absorbed dose to tissue in brachytherapy calculations at clinically relevant distances for low-energy photon emitting seeds is proposed. A correction is introduced that is based on the ratio of the water-to-tissue photon energy-fluences. State-of-the art Monte Carlo calculations are used to score photon fluence differential in energy in water and in various human tissues (muscle, adipose and bone), which in all cases include a realistic modelling of low-energy brachytherapy sources in order to benchmark the formalism proposed. The energy-fluence based corrections given in this work are able to correlate absorbed dose to tissue and absorbed dose to water with an accuracy better than 0.5% in the most critical cases (e.g. bone tissue).

A novel adaptive needle insertion sequencing for robotic, single needle MR-guided high-dose-rate prostate brachytherapy

NASA Astrophysics Data System (ADS)

Borot de Battisti, M.; de Senneville, B. Denis; Hautvast, G.; Binnekamp, D.; Lagendijk, J. J. W.; Maenhout, M.; Moerland, M. A.

2017-05-01

MR-guided high-dose-rate (HDR) brachytherapy has gained increasing interest as a treatment for patients with localized prostate cancer because of the superior value of MRI for tumor and surrounding tissues localization. To enable needle insertion into the prostate with the patient in the MR bore, a single needle MR-compatible robotic system involving needle-by-needle dose delivery has been developed at our institution. Throughout the intervention, dose delivery may be impaired by: (1) sub-optimal needle positioning caused by e.g. needle bending, (2) intra-operative internal organ motion such as prostate rotations or swelling, or intra-procedural rectum or bladder filling. This may result in failure to reach clinical constraints. To assess the first aforementioned challenge, a recent study from our research group demonstrated that the deposited dose may be greatly improved by real-time adaptive planning with feedback on the actual needle positioning. However, the needle insertion sequence is left to the doctor and therefore, this may result in sub-optimal dose delivery. In this manuscript, a new method is proposed to determine and update automatically the needle insertion sequence. This strategy is based on the determination of the most sensitive needle track. The sensitivity of a needle track is defined as its impact on the dose distribution in case of sub-optimal positioning. A stochastic criterion is thus presented to determine each needle track sensitivity based on needle insertion simulations. To assess the proposed sequencing strategy, HDR prostate brachytherapy was simulated on 11 patients with varying number of needle insertions. Sub-optimal needle positioning was simulated at each insertion (modeled by typical random angulation errors). In 91% of the scenarios, the dose distribution improved when the needle was inserted into the most compared to the least sensitive needle track. The computation time for sequencing was less than 6 s per needle track. The proposed needle insertion sequencing can therefore assist in delivering an optimal dose in HDR prostate brachytherapy.

WE-G-BRA-09: Microsphere Brachytherapy Failure Mode and Effects Analysis in a Dual-Vendor Environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Younge, K C; Lee, C I; Feng, M

2015-06-15

Purpose: To improve the safety and quality of a dual-vendor microsphere brachytherapy program with failure mode and effects analysis (FMEA). Methods: A multidisciplinary team including physicists, dosimetrists, a radiation oncologist, an interventional radiologist, and radiation safety personnel performed an FMEA for our dual-vendor microsphere brachytherapy program employing SIR-Spheres (Sirtex Medical Limited, Australia) and Theraspheres (BTG, England). We developed a program process tree and step-by-step instructions which were used to generate a comprehensive list of failure modes. These modes were then ranked according to severity, occurrence rate, and detectability. Risk priority numbers (RPNs) were calculated by multiplying these three scores together.more » Three different severity scales were created: one each for harmful effects to the patient, staff, or the institution. Each failure mode was ranked on one or more of these scales. Results: The group identified 164 failure modes for the microsphere program. 113 of these were ranked using the patient severity scale, 52 using the staff severity scale, and 50 using the institution severity scale. The highest ranked items on the patient severity scale were an error in the automated dosimetry worksheet (RPN = 297.5), and the incorrect target specified on the planning study (RPN = 135). Some failure modes ranked differently between vendors, especially those corresponding to dose vial preparation because of the different methods used. Based on our findings, we made several improvements to our QA program, including documentation to easily identify which product is being used, an additional hand calculation during planning, and reorganization of QA steps before treatment delivery. We will continue to periodically review and revise the FMEA. Conclusion: We have applied FMEA to our dual-vendor microsphere brachytherapy program to identify potential key weaknesses in the treatment chain. Our FMEA results were used to improve the effectiveness of our overall microsphere program.« less

SU-F-T-234: Quality Improvements in the Electronic Medical Record of Patients Treated with High Dose-Rate Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diener, T; Wilkinson, D

Purpose: To improve workflow efficiency and patient safety by assessing the quality control documentation for HDR brachytherapy within our Electronic Medical Record System (Mosaiq). Methods: A list of parameters based on NRC regulations, our quality management program (QMP), recommendations of the ACR and the American Brachytherapy Society, and HDR treatment planning risks identified in our previous FMEA study was made. Next, the parameter entries were classified according to the type of data input—manual, electronic, or both. Manual entry included the electronic Brachytherapy Treatment Record (BTR) and pre-treatment Mosaiq Assessments list. Oncentra Treatment Reports (OTR) from the Oncentra Treatment Control Systemmore » constituted the electronic data. The OTR includes a Pre-treatment Report for each fraction, and a Treatment Summary Report at the completion of treatment. Each entry was then examined for appropriateness and completeness of data; adjustments and additions as necessary were then made. Results: Ten out of twenty-one recorded treatment parameters were identified to be documented within both the BTR and OTR. Of these ten redundancies, eight were changed from recorded values to a simple checklist in the BTR to avoid recording errors. The other redundancies were kept in both documents due to their value to ensuring patient safety. An edit was made to the current BTR quality assessment; this change revises the definition of a medical event in accordance with ODH Regulation 3701:1-58-101. One addition was made to the current QMP documents regarding HDR. This addition requires a physician to be present through the duration of HDR treatment in accordance with ODH Regulation 3701:1-58-59; Paragraph (F); Section (2); Subsection (a). Conclusion: Careful examination of HDR documentation that originates from different sources can help to improve the accuracy and reliability of the documents. In addition, there may be a small improvement in efficiency due to elimination of unnecessary redundancies.« less

WE-G-BRA-07: Analyzing the Safety Implications of a Brachytherapy Process Improvement Project Utilizing a Novel System-Theory-Based Hazard-Analysis Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, A; Samost, A; Viswanathan, A

Purpose: To investigate the hazards in cervical-cancer HDR brachytherapy using a novel hazard-analysis technique, System Theoretic Process Analysis (STPA). The applicability and benefit of STPA to the field of radiation oncology is demonstrated. Methods: We analyzed the tandem and ring HDR procedure through observations, discussions with physicists and physicians, and the use of a previously developed process map. Controllers and their respective control actions were identified and arranged into a hierarchical control model of the system, modeling the workflow from applicator insertion through initiating treatment delivery. We then used the STPA process to identify potentially unsafe control actions. Scenarios weremore » then generated from the identified unsafe control actions and used to develop recommendations for system safety constraints. Results: 10 controllers were identified and included in the final model. From these controllers 32 potentially unsafe control actions were identified, leading to more than 120 potential accident scenarios, including both clinical errors (e.g., using outdated imaging studies for planning), and managerial-based incidents (e.g., unsafe equipment, budget, or staffing decisions). Constraints identified from those scenarios include common themes, such as the need for appropriate feedback to give the controllers an adequate mental model to maintain safe boundaries of operations. As an example, one finding was that the likelihood of the potential accident scenario of the applicator breaking during insertion might be reduced by establishing a feedback loop of equipment-usage metrics and equipment-failure reports to the management controller. Conclusion: The utility of STPA in analyzing system hazards in a clinical brachytherapy system was demonstrated. This technique, rooted in system theory, identified scenarios both technical/clinical and managerial in nature. These results suggest that STPA can be successfully used to analyze safety in brachytherapy and may prove to be an alternative to other hazard analysis techniques.« less

Trends in the Utilization of Brachytherapy in Cervical Cancer in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Kathy, E-mail: Kathy.Han@rmp.uhn.on.ca; Milosevic, Michael; Fyles, Anthony

2013-09-01

Purpose: To determine the trends in brachytherapy use in cervical cancer in the United States and to identify factors and survival benefits associated with brachytherapy treatment. Methods and Materials: Using the Surveillance, Epidemiology, and End Results (SEER) database, we identified 7359 patients with stages IB2-IVA cervical cancer treated with external beam radiation therapy (EBRT) between 1988 and 2009. Propensity score matching was used to adjust for differences between patients who received brachytherapy and those who did not from 2000 onward (after the National Cancer Institute alert recommending concurrent chemotherapy). Results: Sixty-three percent of the 7359 women received brachytherapy in combinationmore » with EBRT, and 37% received EBRT alone. The brachytherapy utilization rate has decreased from 83% in 1988 to 58% in 2009 (P<.001), with a sharp decline of 23% in 2003 to 43%. Factors associated with higher odds of brachytherapy use include younger age, married (vs single) patients, earlier years of diagnosis, earlier stage and certain SEER regions. In the propensity score-matched cohort, brachytherapy treatment was associated with higher 4-year cause-specific survival (CSS; 64.3% vs 51.5%, P<.001) and overall survival (OS; 58.2% vs 46.2%, P<.001). Brachytherapy treatment was independently associated with better CSS (hazard ratio [HR], 0.64; 95% confidence interval [CI], 0.57-0.71), and OS (HR 0.66; 95% CI, 0.60 to 0.74). Conclusions: This population-based analysis reveals a concerning decline in brachytherapy utilization and significant geographic disparities in the delivery of brachytherapy in the United States. Brachytherapy use is independently associated with significantly higher CSS and OS and should be implemented in all feasible cases.« less

Patterns of care for brachytherapy in Europe. Results in Spain.

PubMed

López Torrecilla, J; Guedea, F; Heeren, G; Nissin, R; Ellison, T; Cottier, B

2006-05-01

In 2003 ESTRO began a project whose primary objective, was to make a map in the European area of infrastructures in technology and personnel for brachytherapy. A survey and a web site were elaborated. The survey was sent to the 76 Spanish Radiation Oncology departments in May 2003. By the end of 2003, 66 (86.8%) services had responded, 40 (71.4%) of which had brachytherapy. The services with brachytherapy treated 73.5% of the total patients, an average of 1,199 patients. The mean number of patients treated with brachytherapy by department was 135.5 and the number of applications was 265 annually. The average number of specialists was 7, 4 of them trained in brachytherapy. The average weekly work load of the radiation oncologists, physicists, and technicians was 22.6 h, 13.8 h and 21.0 h, respectively. The mean time dedicated to each patient by radiation oncologists, physicists and technicians was 9.2 h; 6.19 h; 7.2 h, respectively. The total number of afterloaders was 43 (22 HDR, 18 LDR, 3 PDR). The tumours most frequently treated with brachytherapy were gynaecological (56.24%), breast (14.2%) and prostate (11.7%). High dose rate was used in 47.46% of the patients and low dose rate in 47.24%. Between 1997 and 2002 there was an increase of 50.53% in patients treated with brachytherapy. The survey shows the brachytherapy resources and activity in Spain up to 2003. Increased use of brachytherapy in prostate tumours, prevalence of gynaecology brachytherapy and similar number of treatments with HDR and LDR are demonstrated in the Patterns of Care of Brachytherapy in Europe (PCBE) study in Spain.

10 CFR 35.406 - Brachytherapy sources accountability.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Brachytherapy sources accountability. 35.406 Section 35....406 Brachytherapy sources accountability. (a) A licensee shall maintain accountability at all times... area. (c) A licensee shall maintain a record of the brachytherapy source accountability in accordance...

SU-E-T-212: Comparison of TG-43 Dosimetric Parameters of Low and High Energy Brachytherapy Sources Obtained by MCNP Code Versions of 4C, X and 5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zehtabian, M; Zaker, N; Sina, S

2015-06-15

Purpose: Different versions of MCNP code are widely used for dosimetry purposes. The purpose of this study is to compare different versions of the MCNP codes in dosimetric evaluation of different brachytherapy sources. Methods: The TG-43 parameters such as dose rate constant, radial dose function, and anisotropy function of different brachytherapy sources, i.e. Pd-103, I-125, Ir-192, and Cs-137 were calculated in water phantom. The results obtained by three versions of Monte Carlo codes (MCNP4C, MCNPX, MCNP5) were compared for low and high energy brachytherapy sources. Then the cross section library of MCNP4C code was changed to ENDF/B-VI release 8 whichmore » is used in MCNP5 and MCNPX codes. Finally, the TG-43 parameters obtained using the MCNP4C-revised code, were compared with other codes. Results: The results of these investigations indicate that for high energy sources, the differences in TG-43 parameters between the codes are less than 1% for Ir-192 and less than 0.5% for Cs-137. However for low energy sources like I-125 and Pd-103, large discrepancies are observed in the g(r) values obtained by MCNP4C and the two other codes. The differences between g(r) values calculated using MCNP4C and MCNP5 at the distance of 6cm were found to be about 17% and 28% for I-125 and Pd-103 respectively. The results obtained with MCNP4C-revised and MCNPX were similar. However, the maximum difference between the results obtained with the MCNP5 and MCNP4C-revised codes was 2% at 6cm. Conclusion: The results indicate that using MCNP4C code for dosimetry of low energy brachytherapy sources can cause large errors in the results. Therefore it is recommended not to use this code for low energy sources, unless its cross section library is changed. Since the results obtained with MCNP4C-revised and MCNPX were similar, it is concluded that the difference between MCNP4C and MCNPX is their cross section libraries.« less

SU-E-T-509: Inter-Observer and Inter-Modality Contouring Analysis for Organs at Risk for HDR Gynecological Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadeghi, P; Smith, W; Tom Baker Cancer Centre, Calgary, AB

2015-06-15

Purpose This study quantifies errors associated with MR-guided High Dose Rate (HDR) gynecological brachytherapy. Uncertainties in this treatment results from contouring, organ motion between imaging and treatment delivery, dose calculation, and dose delivery. We focus on interobserver and inter-modality variability in contouring and the motion of organs at risk (OARs) in the time span between the MR and CT scans (∼1 hour). We report the change in organ volume and position of center of mass (CM) between the two imaging modalities. Methods A total of 8 patients treated with MR-guided HDR brachytherapy were included in this study. Two observers contouredmore » the bladder and rectum on both MR and CT scans. The change in OAR volume and CM position between the MR and CT imaging sessions on both image sets were calculated. Results The absolute mean bladder volume change between the two imaging modalities is 67.1cc. The absolute mean inter-observer difference in bladder volume is much lower at 15.5cc (MR) and 11.0cc (CT). This higher inter-modality volume difference suggests a real change in the bladder filling between the two imaging sessions. Change in Rectum volume inter-observer standard error of means (SEM) is 3.18cc (MR) and 3.09cc (CT), while the inter-modality SEM is 3.65cc (observer 1), and 2.75cc (observer 2). The SEM for rectum CM position in the superior-inferior direction was approximately three times higher than in other directions for both the inter—observer (0.77 cm, 0.92 cm for observers 1 and 2, respectively) and inter-modality (0.91 cm, 0.95 cm for MR and CT, respectively) variability. Conclusion Bladder contours display good consistency between different observers on both CT and MR images. For rectum contouring the highest inconsistency stems from the observers’ choice of the superior-inferior borders. A complete analysis of a larger patient cohort will enable us to separate the true organ motion from the inter-observer variability.« less

CT, MR, and ultrasound image artifacts from prostate brachytherapy seed implants: The impact of seed size

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robertson, Andrew K. H.; Basran, Parminder S.; Thomas, Steven D.

Purpose: To investigate the effects of brachytherapy seed size on the quality of x-ray computed tomography (CT), ultrasound (US), and magnetic resonance (MR) images and seed localization through comparison of the 6711 and 9011 {sup 125}I sources. Methods: For CT images, an acrylic phantom mimicking a clinical implantation plan and embedded with low contrast regions of interest (ROIs) was designed for both the 0.774 mm diameter 6711 (standard) and the 0.508 mm diameter 9011 (thin) seed models (Oncura, Inc., and GE Healthcare, Arlington Heights, IL). Image quality metrics were assessed using the standard deviation of ROIs between the seeds andmore » the contrast to noise ratio (CNR) within the low contrast ROIs. For US images, water phantoms with both single and multiseed arrangements were constructed for both seed sizes. For MR images, both seeds were implanted into a porcine gel and imaged with pelvic imaging protocols. The standard deviation of ROIs and CNR values were used as metrics of artifact quantification. Seed localization within the CT images was assessed using the automated seed finder in a commercial brachytherapy treatment planning system. The number of erroneous seed placements and the average and maximum error in seed placements were recorded as metrics of the localization accuracy. Results: With the thin seeds, CT image noise was reduced from 48.5 {+-} 0.2 to 32.0 {+-} 0.2 HU and CNR improved by a median value of 74% when compared with the standard seeds. Ultrasound image noise was measured at 50.3 {+-} 17.1 dB for the thin seed images and 50.0 {+-} 19.8 dB for the standard seed images, and artifacts directly behind the seeds were smaller and less prominent with the thin seed model. For MR images, CNR of the standard seeds reduced on average 17% when using the thin seeds for all different imaging sequences and seed orientations, but these differences are not appreciable. Automated seed localization required an average ({+-}SD) of 7.0 {+-} 3.5 manual corrections in seed positions for the thin seed scans and 3.0 {+-} 1.2 manual corrections in seed positions for the standard seed scans. The average error in seed placement was 1.2 mm for both seed types and the maximum error in seed placement was 2.1 mm for the thin seed scans and 1.8 mm for the standard seed scans. Conclusions: The 9011 thin seeds yielded significantly improved image quality for CT and US images but no significant differences in MR image quality.« less

Radioactive implant migration in patients treated for localized prostate cancer with interstitial brachytherapy.

PubMed

Older, R A; Synder, B; Krupski, T L; Glembocki, D J; Gillenwater, J Y

2001-05-01

In several of the initial patients undergoing brachytherapy at our institution radioactive implants were visible in the thorax on chest radiography. The clinical ramifications of this unanticipated finding were unclear. Thus, we investigated the incidence of brachytherapy seed migration to the chest and whether these seeds were associated with any clinical significance. We retrospectively reviewed the records of all patients who underwent ultrasound or computerized tomography guided brachytherapy of 103palladium seeds from March 1997 to March 1999. This list of patients on brachytherapy was then matched against the radiology computer system to determine those who had undergone chest X-ray after brachytherapy. When the radiology report was unclear regarding brachytherapy seeds, chest x-rays were reviewed by one of us (R. O.) to determine the presence and position of the seeds. Post-brachytherapy chest x-rays were available in 110 of the 183 patients. In 78 cases no brachytherapy seeds were identified. Radioactive implants were identified on chest radiography in 32 patients (29%), including 1 to 5 seeds in 20, 8, 1, 2 and 1, respectively. No patients complained of any change in pulmonary symptoms after brachytherapy. Radioactive implants migrated after brachytherapy for localized prostate cancer in 29% of the patients who underwent post-procedure radiography. There did not appear to be a pattern to the seed distribution. However, while the incidence was not negligible, no patient appeared to have any acute pulmonary symptoms. Therefore, while the migration of radioactive implants to the chest is a real phenomenon, it appears to have no adverse clinical consequences in the early post-procedure period.

Efficacy and safety of iodine-125 radioactive seeds brachytherapy for advanced non-small cell lung cancer-A meta-analysis.

PubMed

Zhang, Wenchao; Li, Jiawei; Li, Ran; Zhang, Ying; Han, Mingyong; Ma, Wei

This meta-analysis was conducted to investigate the efficacy and safety of 125 I brachytherapy for locally advanced non-small cell lung cancer (NSCLC). Trials comparing 125 I brachytherapy with chemotherapy in NSCLC were identified. Meta-analysis was performed to obtain pooled risk ratios for an overall response rate (ORR), disease control rate (DCR) and complications, and pooled hazard ratio for overall survival (OS). Fifteen studies including 1188 cases were included. The pooled result indicated that there were significant differences in ORR, DCR, and OS between 125 I brachytherapy combined with chemotherapy and chemotherapy alone, but no statistic differences in gastrointestinal symptoms, leukopenia, myelosuppression, and hemoglobin reduction. Patients treated with 125 I brachytherapy combined with chemotherapy have a higher relative risk of pneumothorax, bloody sputum, and pneumorrhagia compared with chemotherapy alone. Seeds migration only occurred in the group treated with 125 I brachytherapy. There were significant differences in ORR, DCR, and myelosuppression between 125 I brachytherapy alone and chemotherapy. 125 I brachytherapy combined with chemotherapy can significantly enhance the clinical efficacy and improve the OS of patients with advanced NSCLC without increasing the incidence of complications of chemotherapy. 125 I brachytherapy alone can significantly enhance the clinical efficacy and reduce the incidence of myelosuppression compared with chemotherapy. However, 125 I brachytherapy may cause lung injury. Large sample and higher-quality randomized controlled trials are needed to confirm the pooled results of complications. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

New era of electronic brachytherapy

PubMed Central

Ramachandran, Prabhakar

2017-01-01

Traditional brachytherapy refers to the placement of radioactive sources on or inside the cancer tissues. Based on the type of sources, brachytherapy can be classified as radionuclide and electronic brachytherapy. Electronic brachytherapy uses miniaturized X-ray sources instead of radionuclides to deliver high doses of radiation. The advantages of electronic brachytherapy include low dose to organs at risk, reduced dose to treating staff, no leakage radiation in off state, less shielding, and no radioactive waste. Most of these systems operate between 50 and 100 kVp and are widely used in the treatment of skin cancer. Intrabeam, Xoft and Papillon systems are also used in the treatment of intra-operative radiotherapy to breast in addition to other treatment sites. The rapid fall-off in the dose due to its low energy is a highly desirable property in brachytherapy and results in a reduced dose to the surrounding normal tissues compared to the Ir-192 source. The Xoft Axxent brachytherapy system uses a 2.25 mm miniaturized X-ray tube and the source almost mimics the high dose rate Ir-192 source in terms of dose rate and it is the only electronic brachytherapy system specifically used in the treatment of cervical cancers. One of the limiting factors that impede the use of electronic brachytherapy for interstitial application is the source dimension. However, it is highly anticipated that the design of miniaturized X-ray tube closer to the dimension of an Ir-192 wire is not too far away, and the new era of electronic brachytherapy has just begun. PMID:28529679

10 CFR 35.2406 - Records of brachytherapy source accountability.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Records of brachytherapy source accountability. 35.2406... Records of brachytherapy source accountability. (a) A licensee shall maintain a record of brachytherapy source accountability required by § 35.406 for 3 years. (b) For temporary implants, the record must...

Magnetic resonance imaging in prostate brachytherapy: Evidence, clinical end points to data, and direction forward.

PubMed

Pugh, Thomas J; Pokharel, Sajal S

The integration of multiparametric MRI into prostate brachytherapy has become a subject of interest over the past 2 decades. MRI directed high-dose-rate and low-dose-rate prostate brachytherapy offers the potential to improve treatment accuracy and standardize postprocedure quality. This article reviews the evidence to date on MRI utilization in prostate brachytherapy and postulates future pathways for MRI integration. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Mental Nerve Blocks for Lip Brachytherapy: A Case Report.

PubMed

Hafez, Osama; Ackerman, Robert S; Evans, Trip; Patel, Sephalie Y; Padalia, Devang M

2018-05-15

High dose rate interstitial brachytherapy is a commonly performed procedure for carcinoma of the lower lip. Placement of the brachytherapy catheters can be painful and may require monitored anesthesia care or general anesthesia. We present the use of bilateral mental nerve blocks with minimal sedation to facilitate placement of brachytherapy catheters.

[Brachytherapy in France: current situation and economic outlook due to the unavailability of iridium wires].

PubMed

Le Vu, B; Boucher, S

2014-10-01

In 2013, about 6000 patients were treated with brachytherapy, the number diminishing by 2.6% per year since 2008. Prostate, breast and gynecological cancers are the most common types of cancers. Since 2008, the number of brachytherapy facilities has decreased by 18%. In medicoeconomic terms, brachytherapy faces many problems: the coding system is outdated; brachytherapy treatments cost as much as internal radiation; fees do not cover costs; since iridium wire has disappeared from the market, the technique will be transferred to more expensive high-speed or pulse dose rates. The French financing grid based on the national study of costs lags behind changes in such treatments and in the best of cases, hospitals resorting to alternatives such as in-hospital brachytherapy are funded at 46% of their additional costs. Brachytherapy is a reference technique. With intense pressure on hospital pricing, financing brachytherapy facilities will become even more problematic as a consequence of the disappearance of iridium 192 wires. The case of brachytherapy illustrates the limits of the French financing system and raises serious doubts as to its responsiveness. Copyright © 2014 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

SU-F-T-243: Major Risks in Radiotherapy. A Review Based On Risk Analysis Literature

DOE Office of Scientific and Technical Information (OSTI.GOV)

López-Tarjuelo, J; Guasp-Tortajada, M; Iglesias-Montenegro, N

Purpose: We present a literature review of risk analyses in radiotherapy to highlight the most reported risks and facilitate the spread of this valuable information so that professionals can be aware of these major threats before performing their own studies. Methods: We considered studies with at least an estimation of the probability of occurrence of an adverse event (O) and its associated severity (S). They cover external beam radiotherapy, brachytherapy, intraoperative radiotherapy, and stereotactic techniques. We selected only the works containing a detailed ranked series of elements or failure modes and focused on the first fully reported quartile as much.more » Afterward, we sorted the risk elements according to a regular radiotherapy procedure so that the resulting groups were cited in several works and be ranked in this way. Results: 29 references published between 2007 and February 2016 were studied. Publication trend has been generally rising. The most employed analysis has been the Failure mode and effect analysis (FMEA). Among references, we selected 20 works listing 258 ranked risk elements. They were sorted into 31 groups appearing at least in two different works. 11 groups appeared in at least 5 references and 5 groups did it in 7 or more papers. These last sets of risks where choosing another set of images or plan for planning or treating, errors related with contours, errors in patient positioning for treatment, human mistakes when programming treatments, and planning errors. Conclusion: There is a sufficient amount and variety of references for identifying which failure modes or elements should be addressed in a radiotherapy department before attempting a specific analysis. FMEA prevailed, but other studies such as “risk matrix” or “occurrence × severity” analyses can also lead professionals’ efforts. Risk associated with human actions ranks very high; therefore, they should be automated or at least peer-reviewed.« less

High dose rate brachytherapy for oral cancer

PubMed Central

YamazakI, Hideya; Yoshida, Ken; Yoshioka, Yasuo; Shimizutani, Kimishige; Furukawa, Souhei; Koizumi, Masahiko; Ogawa, Kazuhiko

2013-01-01

Brachytherapy results in better dose distribution compared with other treatments because of steep dose reduction in the surrounding normal tissues. Excellent local control rates and acceptable side effects have been demonstrated with brachytherapy as a sole treatment modality, a postoperative method, and a method of reirradiation. Low-dose-rate (LDR) brachytherapy has been employed worldwide for its superior outcome. With the advent of technology, high-dose-rate (HDR) brachytherapy has enabled health care providers to avoid radiation exposure. This therapy has been used for treating many types of cancer such as gynecological cancer, breast cancer, and prostate cancer. However, LDR and pulsed-dose-rate interstitial brachytherapies have been mainstays for head and neck cancer. HDR brachytherapy has not become widely used in the radiotherapy community for treating head and neck cancer because of lack of experience and biological concerns. On the other hand, because HDR brachytherapy is less time-consuming, treatment can occasionally be administered on an outpatient basis. For the convenience and safety of patients and medical staff, HDR brachytherapy should be explored. To enhance the role of this therapy in treatment of head and neck lesions, we have reviewed its outcomes with oral cancer, including Phase I/II to Phase III studies, evaluating this technique in terms of safety and efficacy. In particular, our studies have shown that superficial tumors can be treated using a non-invasive mold technique on an outpatient basis without adverse reactions. The next generation of image-guided brachytherapy using HDR has been discussed. In conclusion, although concrete evidence is yet to be produced with a sophisticated study in a reproducible manner, HDR brachytherapy remains an important option for treatment of oral cancer. PMID:23179377

High dose rate brachytherapy for oral cancer.

PubMed

Yamazaki, Hideya; Yoshida, Ken; Yoshioka, Yasuo; Shimizutani, Kimishige; Furukawa, Souhei; Koizumi, Masahiko; Ogawa, Kazuhiko

2013-01-01

Brachytherapy results in better dose distribution compared with other treatments because of steep dose reduction in the surrounding normal tissues. Excellent local control rates and acceptable side effects have been demonstrated with brachytherapy as a sole treatment modality, a postoperative method, and a method of reirradiation. Low-dose-rate (LDR) brachytherapy has been employed worldwide for its superior outcome. With the advent of technology, high-dose-rate (HDR) brachytherapy has enabled health care providers to avoid radiation exposure. This therapy has been used for treating many types of cancer such as gynecological cancer, breast cancer, and prostate cancer. However, LDR and pulsed-dose-rate interstitial brachytherapies have been mainstays for head and neck cancer. HDR brachytherapy has not become widely used in the radiotherapy community for treating head and neck cancer because of lack of experience and biological concerns. On the other hand, because HDR brachytherapy is less time-consuming, treatment can occasionally be administered on an outpatient basis. For the convenience and safety of patients and medical staff, HDR brachytherapy should be explored. To enhance the role of this therapy in treatment of head and neck lesions, we have reviewed its outcomes with oral cancer, including Phase I/II to Phase III studies, evaluating this technique in terms of safety and efficacy. In particular, our studies have shown that superficial tumors can be treated using a non-invasive mold technique on an outpatient basis without adverse reactions. The next generation of image-guided brachytherapy using HDR has been discussed. In conclusion, although concrete evidence is yet to be produced with a sophisticated study in a reproducible manner, HDR brachytherapy remains an important option for treatment of oral cancer.

Phase I/II prospective trial of cancer-specific imaging using ultrasound spectrum analysis tissue-type imaging to guide dose-painting prostate brachytherapy.

PubMed

Ennis, Ronald D; Quinn, S Aidan; Trichter, Frieda; Ryemon, Shannon; Jain, Anudh; Saigal, Kunal; Chandrashekhar, Sarayu; Romas, Nicholas A; Feleppa, Ernest J

2015-01-01

To assess the technical feasibility, toxicity, dosimetry, and preliminary efficacy of dose-painting brachytherapy guided by ultrasound spectrum analysis tissue-type imaging (TTI) in low-risk, localized prostate cancer. Fourteen men with prostate cancer who were candidates for brachytherapy as sole treatment were prospectively enrolled. Treatment planning goal was to escalate the tumor dose to 200% with a modest de-escalation of dose to remaining prostate compared with our standard. Primary end points included technical feasibility of TTI-guided brachytherapy and equivalent or better toxicity compared with standard brachytherapy. Secondary end points included dose escalation to tumor regions and de-escalated dose to nontumor regions on the preimplant plan, negative prostate biopsy at 2 years, and freedom from biochemical failure. Thirteen of fourteen men successfully completed the TTI-guided brachytherapy procedure for a feasibility rate of 93%. A software malfunction resulted in switching one patient from TTI-guided to standard brachytherapy. An average of 2.7 foci per patient was demonstrated and treated with an escalated dose. Dosimetric goals on preplan were achieved. One patient expired from unrelated causes 65 days after brachytherapy. Toxicity was at least as low as standard brachytherapy. Two-year prostate biopsies were obtained from six men; five (83%) were definitively negative, one showed evidence of disease with treatment effect, and none were positive. No patients experienced biochemical recurrence after a median followup of 31.5 (24-52) months. We have demonstrated that TTI-guided dose-painting prostate brachytherapy is technically feasible and results in clinical outcomes that are encouraging in terms of low toxicity and successful biochemical disease control. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

LDR vs. HDR brachytherapy for localized prostate cancer: the view from radiobiological models.

PubMed

King, Christopher R

2002-01-01

Permanent LDR brachytherapy and temporary HDR brachytherapy are competitive techniques for clinically localized prostate radiotherapy. Although a randomized trial will likely never be conducted comparing these two forms of brachytherapy, a comparative radiobiological modeling analysis proves useful in understanding some of their intrinsic differences, several of which could be exploited to improve outcomes. Radiobiological models based upon the linear quadratic equations are presented for fractionated external beam, fractionated (192)Ir HDR brachytherapy, and (125)I and (103)Pd LDR brachytherapy. These models incorporate the dose heterogeneities present in brachytherapy based upon patient-derived dose volume histograms (DVH) as well as tumor doubling times and repair kinetics. Radiobiological parameters are normalized to correspond to three accepted clinical risk factors based upon T-stage, PSA, and Gleason score to compare models with clinical series. Tumor control probabilities (TCP) for LDR and HDR brachytherapy (as monotherapy or combined with external beam) are compared with clinical bNED survival rates. Predictions are made for dose escalation with HDR brachytherapy regimens. Model predictions for dose escalation with external beam agree with clinical data and validate the models and their underlying assumptions. Both LDR and HDR brachytherapy achieve superior tumor control when compared with external beam at conventional doses (<70 Gy), but similar to results from dose escalation series. LDR brachytherapy as boost achieves superior tumor control than when used as monotherapy. Stage for stage, both LDR and current HDR regimens achieve similar tumor control rates, in agreement with current clinical data. HDR monotherapy with large-dose fraction sizes might achieve superior tumor control compared with LDR, especially if prostate cancer possesses a high sensitivity to dose fractionation (i.e., if the alpha/beta ratio is low). Radiobiological models support the current clinical evidence for equivalent outcomes in localized prostate cancer with either LDR or HDR brachytherapy using current dose regimens. However, HDR brachytherapy dose escalation regimens might be able to achieve higher biologically effective doses of irradiation in comparison to LDR, and hence improved outcomes. This advantage over LDR would be amplified should prostate cancer possess a high sensitivity to dose fractionation (i.e., a low alpha/beta ratio) as the current evidence suggests.

Contemporary Toxicity Profile of Breast Brachytherapy Versus External Beam Radiation After Lumpectomy for Breast Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huo, Jinhai; Giordano, Sharon H.; Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas

Purpose: We compared toxicities after brachytherapy versus external beam radiation therapy (EBRT) in contemporary breast cancer patients. Methods and Materials: Using MarketScan healthcare claims, we identified 64,112 women treated from 2003 to 2012 with lumpectomy followed by radiation (brachytherapy vs EBRT). Brachytherapy was further classified by multichannel versus single-channel applicator approach. We identified the risks and predictors of 1-year infectious and noninfectious postoperative adverse events using logistic regression and temporal trends using Cochran-Armitage tests. We estimated the 5-year Kaplan-Meier cumulative incidence of radiation-associated adverse events. Results: A total of 4522 (7.1%) patients received brachytherapy (50.2% multichannel vs 48.7% single-channel applicator).more » The overall risk of infectious adverse events was higher after brachytherapy than after EBRT (odds ratio [OR] = 1.21; 95% confidence interval [CI] 1.09-1.34, P<.001). However, over time, the frequency of infectious adverse events after brachytherapy decreased, from 17.3% in 2003 to 11.6% in 2012, and was stable after EBRT at 9.7%. Beyond 2007, there were no longer excess infections with brachytherapy (P=.97). The overall risk of noninfectious adverse events was higher after brachytherapy than after EBRT (OR=2.27; 95% CI 2.09-2.47, P<.0001). Over time, the frequency of noninfectious adverse events detected increased: after multichannel brachytherapy, from 9.1% in 2004 to 18.9% in 2012 (Ptrend = .64); single-channel brachytherapy, from 12.8% to 29.8% (Ptrend<.001); and EBRT, from 6.1% to 10.3% (Ptrend<.0001). The risk was significantly higher with single-channel than with multichannel brachytherapy (hazard ratio = 1.32; 95% CI 1.03-1.69, P=.03). Of noninfectious adverse events, 70.9% were seroma. Seroma significantly increased breast pain risk (P<.0001). Patients with underlying diabetes, cardiovascular disease, and treatment with chemotherapy had increased infectious and noninfectious adverse events. The 5-year incidences of fat necrosis, breast pain, and rib fracture were slightly higher after brachytherapy than after EBRT (13.7% vs 8.1%, 19.4% vs 16.0%, and 1.6% vs 1.3%, respectively), but the risks were not significantly different for multichannel versus single-channel applicators. Conclusion: Toxicities after breast brachytherapy were distinct from those after EBRT. Temporal toxicity trends may reflect changing technology and evolving practitioner experience with brachytherapy.« less

Comparison of parameters affecting GNP-loaded choroidal melanoma dosimetry; Monte Carlo study

NASA Astrophysics Data System (ADS)

Sharabiani, Marjan; Asadi, Somayeh; Barghi, Amir Rahnamai; Vaezzadeh, Mehdi

2018-04-01

The current study reports the results of tumor dosimetry in the presence of gold nanoparticles (GNPs) with different sizes and concentrations. Due to limited number of works carried out on the brachytherapy of choroidal melanoma in combination with GNPs, this study was performed to determine the optimum size and concentration for GNPs which contributes the highest dose deposition in tumor region, using two phantom test cases namely water phantom and a full Monte Carlo model of human eye. Both water and human eye phantoms were simulated with MCNP5 code. Tumor dosimetry was performed for a typical point photon source with an energy of 0.38 MeV as a high energy source and 103Pd brachytherapy source with an average energy of 0.021 MeV as a low energy source in water phantom and eye phantom respectively. Such a dosimetry was done for different sizes and concentrations of GNPs. For all of the diameters, increase in concentration of GNPs resulted in an increase in dose deposited in the region of interest. In a certain concentration, GNPs with larger diameters contributed more dose to the tumor region, which was more pronounced using eye phantom. 100 nm was reported as the optimum size in order to achieve the highest energy deposition within the target. This work investigated the optimum parameters affecting macroscopic dose enhancement in GNP-aided brachytherapy of choroidal melanoma. The current work also had implications on using low energy photon sources in the presence of GNPs to acquire the highest dose enhancement. This study is conducted through four different sizes and concentrations of GNPs. Considering the sensitivity of human eye tissue, in order to report the precise optimum parameters affecting radiosensitivity, a comprehensive study on a wide range of sizes and concentrations are required.

In vivo photoacoustic imaging of prostate brachytherapy seeds

NASA Astrophysics Data System (ADS)

Lediju Bell, Muyinatu A.; Kuo, Nathanael P.; Song, Danny Y.; Kang, Jin; Boctor, Emad M.

2014-03-01

We conducted an approved canine study to investigate the in vivo feasibility of photoacoustic imaging for intraoperative updates to brachytherapy treatment plans. Brachytherapy seeds coated with black ink were inserted into the canine prostate using methods similar to a human procedure. A transperineal, interstitial, fiber optic light delivery method, coupled to a 1064 nm laser, was utilized to irradiate the prostate and the resulting acoustic waves were detected with a transrectal ultrasound probe. The fiber was inserted into a high dose rate (HDR) brachytherapy needle that acted as a light-diffusing sheath, enabling radial light delivery from the tip of the fiber inside the sheath. The axis of the fiber was located at a distance of 4-9 mm from the long axis of the cylindrical seeds. Ultrasound images acquired with the transrectal probe and post-operative CT images of the implanted seeds were analyzed to confirm seed locations. In vivo limitations with insufficient light delivery within the ANSI laser safety limit (100 mJ/cm2) were overcome by utilizing a short-lag spatial coherence (SLSC) beamformer, which provided average seed contrasts of 20-30 dB for energy densities ranging 8-84 mJ/cm2. The average contrast was improved by up to 20 dB with SLSC beamforming compared to conventional delay-and-sum beamforming. There was excellent agreement between photoacoustic, ultrasound, and CT images. Challenges included visualization of photoacoustic artifacts that corresponded with locations of the optical fiber and hyperechoic tissue structures.

Comparison of TG-43 dosimetric parameters of brachytherapy sources obtained by three different versions of MCNP codes.

PubMed

Zaker, Neda; Zehtabian, Mehdi; Sina, Sedigheh; Koontz, Craig; Meigooni, Ali S

2016-03-08

Monte Carlo simulations are widely used for calculation of the dosimetric parameters of brachytherapy sources. MCNP4C2, MCNP5, MCNPX, EGS4, EGSnrc, PTRAN, and GEANT4 are among the most commonly used codes in this field. Each of these codes utilizes a cross-sectional library for the purpose of simulating different elements and materials with complex chemical compositions. The accuracies of the final outcomes of these simulations are very sensitive to the accuracies of the cross-sectional libraries. Several investigators have shown that inaccuracies of some of the cross section files have led to errors in 125I and 103Pd parameters. The purpose of this study is to compare the dosimetric parameters of sample brachytherapy sources, calculated with three different versions of the MCNP code - MCNP4C, MCNP5, and MCNPX. In these simulations for each source type, the source and phantom geometries, as well as the number of the photons, were kept identical, thus eliminating the possible uncertainties. The results of these investigations indicate that for low-energy sources such as 125I and 103Pd there are discrepancies in gL(r) values. Discrepancies up to 21.7% and 28% are observed between MCNP4C and other codes at a distance of 6 cm for 103Pd and 10 cm for 125I from the source, respectively. However, for higher energy sources, the discrepancies in gL(r) values are less than 1.1% for 192Ir and less than 1.2% for 137Cs between the three codes.

WE-A-17A-10: Fast, Automatic and Accurate Catheter Reconstruction in HDR Brachytherapy Using An Electromagnetic 3D Tracking System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poulin, E; Racine, E; Beaulieu, L

2014-06-15

Purpose: In high dose rate brachytherapy (HDR-B), actual catheter reconstruction protocols are slow and errors prompt. The purpose of this study was to evaluate the accuracy and robustness of an electromagnetic (EM) tracking system for improved catheter reconstruction in HDR-B protocols. Methods: For this proof-of-principle, a total of 10 catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a Philips-design 18G biopsy needle (used as an EM stylet) and the second generation Aurora Planar Field Generator from Northern Digital Inc. The Aurora EM system exploits alternating current technology and generates 3D points at 40 Hz. Phantomsmore » were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical CT system with a resolution of 0.089 mm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, 5 catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 seconds or less. This would imply that for a typical clinical implant of 17 catheters, the total reconstruction time would be less than 3 minutes. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.92 ± 0.37 mm and 1.74 ± 1.39 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be significantly more accurate (unpaired t-test, p < 0.05). A mean difference of less than 0.5 mm was found between successive EM reconstructions. Conclusion: The EM reconstruction was found to be faster, more accurate and more robust than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators. We would like to disclose that the equipments, used in this study, is coming from a collaboration with Philips Medical.« less

Advantages of high-dose rate (HDR) brachytherapy in treatment of prostate cancer

NASA Astrophysics Data System (ADS)

Molokov, A. A.; Vanina, E. A.; Tseluyko, S. S.

2017-09-01

One of the modern methods of preserving organs radiation treatment is brachytherapy. This article analyzes the results of prostate brachytherapy. These studies of the advantages of high dose brachytherapy lead to the conclusion that this method of radiation treatment for prostate cancer has a favorable advantage in comparison with remote sensing methods, and is competitive, preserving organs in comparison to surgical methods of treatment. The use of the method of polyfocal transperineal biopsy during the brachytherapy session provides information on the volumetric spread of prostate cancer and adjust the dosimetry plan taking into account the obtained data.

State-of-the-art: prostate LDR brachytherapy.

PubMed

Voulgaris, S; Nobes, J P; Laing, R W; Langley, S E M

2008-01-01

This article on low dose rate (LDR) prostate brachytherapy reviews long-term results, patient selection and quality of life issues. Mature results from the United States and United Kingdom are reported and issues regarding definitions of biochemical failure are discussed. Latest data comparing brachytherapy with radical prostatectomy or no definitive treatment and also the risk of secondary malignancies after prostate brachytherapy are presented. Urological parameters of patient selection and quality of life issues concerning urinary, sexual and bowel function are reviewed. The position of prostate brachytherapy next to surgery as a first-line treatment modality is demonstrated.

SU-F-P-42: “To Navigate, Or Not to Navigate: HDR BT in Recurrent Spine Lesions”

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voros, L; Cohen, G; Zaider, M

Purpose: We compare the accuracy of HDR catheter placement for paraspinal lesions using O-arm CBCT imaging combined with StealthStation navigation and traditional fluoroscopically guided catheter placement. Methods: CT and MRI scans were acquired pre-treatment to outline the lesions and design treatment plans (pre-plans) to meet dosimetric constrains. The pre-planned catheter trajectories were transferred into the StealthStation Navigation system prior to the surgery. The StealthStation is an infra red (IR) optical navigation system used for guidance of surgical instruments. An intraoperative CBCT scan (O-arm) was acquired with reference IR optical fiducials anchored onto the patient and registered with the preplan imagemore » study to guide surgical instruments in relation to the patients’ anatomy and to place the brachytherapy catheters along the pre-planned trajectories. The final treatment plan was generated based on a 2nd intraoperative CBCT scan reflecting achieved implant geometry. The 2nd CBCT was later registered with the initial CT scan to compare the preplanned dwell positions with actual dwell positions (catheter placements). Similar workflow was used in placement of 8 catheters (1 patient) without navigation, but under fluoroscopy guidance in an interventional radiology suite. Results: A total of 18 catheters (3 patients) were placed using navigation assisted surgery. Average displacement of 0.66 cm (STD=0.37cm) was observed between the pre-plan source positions and actual source positions in the 3 dimensional space. This translates into an average 0.38 cm positioning error in one direction including registration errors, digitization errors, and the surgeons ability to follow the planned trajectory. In comparison, average displacement of non-navigated catheters was 0.50 cm (STD=0.22cm). Conclusion: Spinal lesion HDR brachytherapy planning is a difficult task. Catheter placement has a direct impact on target coverage and dose to critical structures. While limited to a handful of patients, our experience shows navigation and fluoroscopy guided placement yield similar results.« less

SU-F-T-20: Novel Catheter Lumen Recognition Algorithm for Rapid Digitization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dise, J; McDonald, D; Ashenafi, M

Purpose: Manual catheter recognition remains a time-consuming aspect of high-dose-rate brachytherapy (HDR) treatment planning. In this work, a novel catheter lumen recognition algorithm was created for accurate and rapid digitization. Methods: MatLab v8.5 was used to create the catheter recognition algorithm. Initially, the algorithm searches the patient CT dataset using an intensity based k-means filter designed to locate catheters. Once the catheters have been located, seed points are manually selected to initialize digitization of each catheter. From each seed point, the algorithm searches locally in order to automatically digitize the remaining catheter. This digitization is accomplished by finding pixels withmore » similar image curvature and divergence parameters compared to the seed pixel. Newly digitized pixels are treated as new seed positions, and hessian image analysis is used to direct the algorithm toward neighboring catheter pixels, and to make the algorithm insensitive to adjacent catheters that are unresolvable on CT, air pockets, and high Z artifacts. The algorithm was tested using 11 HDR treatment plans, including the Syed template, tandem and ovoid applicator, and multi-catheter lung brachytherapy. Digitization error was calculated by comparing manually determined catheter positions to those determined by the algorithm. Results: he digitization error was 0.23 mm ± 0.14 mm axially and 0.62 mm ± 0.13 mm longitudinally at the tip. The time of digitization, following initial seed placement was less than 1 second per catheter. The maximum total time required to digitize all tested applicators was 4 minutes (Syed template with 15 needles). Conclusion: This algorithm successfully digitizes HDR catheters for a variety of applicators with or without CT markers. The minimal axial error demonstrates the accuracy of the algorithm, and its insensitivity to image artifacts and challenging catheter positioning. Future work to automatically place initial seed positions would improve the algorithm speed.« less

Low-dose-rate or high-dose-rate brachytherapy in treatment of prostate cancer – between options

PubMed Central

2013-01-01

Purpose Permanent low-dose-rate (LDR-BT) and temporary high-dose-rate (HDR-BT) brachytherapy are competitive techniques for clinically localized prostate radiotherapy. Although a randomized trial will likely never to be conducted comparing these two forms of brachytherapy, a comparative analysis proves useful in understanding some of their intrinsic differences, several of which could be exploited to improve outcomes. The aim of this paper is to look for possible similarities and differences between both brachytherapy modalities. Indications and contraindications for monotherapy and for brachytherapy as a boost to external beam radiation therapy (EBRT) are presented. It is suggested that each of these techniques has attributes that advocates for one or the other. First, they represent the extreme ends of the spectrum with respect to dose rate and fractionation, and therefore have inherently different radiobiological properties. Low-dose-rate brachytherapy has the great advantage of being practically a one-time procedure, and enjoys a long-term follow-up database supporting its excellent outcomes and low morbidity. Low-dose-rate brachytherapy has been a gold standard for prostate brachytherapy in low risk patients since many years. On the other hand, HDR is a fairly invasive procedure requiring several sessions associated with a brief hospital stay. Although lacking in significant long-term data, it possesses the technical advantage of control over its postimplant dosimetry (by modulating the source dwell time and position), which is absent in LDR brachytherapy. This important difference in dosimetric control allows HDR doses to be escalated safely, a flexibility that does not exist for LDR brachytherapy. Conclusions Radiobiological models support the current clinical evidence for equivalent outcomes in localized prostate cancer with either LDR or HDR brachytherapy, using current dose regimens. At present, all available clinical data regarding these two techniques suggests that they are equally effective, stage for stage, in providing high tumor control rates. PMID:23634153

MO-E-BRD-03: Intra-Operative Breast Brachytherapy: Is One Stop Shopping Best? [Non-invasive Image-Guided Breast Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, B.

2015-06-15

Is Non-invasive Image-Guided Breast Brachytherapy Good? – Jess Hiatt, MS Non-invasive Image-Guided Breast Brachytherapy (NIBB) is an emerging therapy for breast boost treatments as well as Accelerated Partial Breast Irradiation (APBI) using HDR surface breast brachytherapy. NIBB allows for smaller treatment volumes while maintaining optimal target coverage. Considering the real-time image-guidance and immobilization provided by the NIBB modality, minimal margins around the target tissue are necessary. Accelerated Partial Breast Irradiation in brachytherapy: is shorter better? - Dorin Todor, PhD VCU A review of balloon and strut devices will be provided together with the origins of APBI: the interstitial multi-catheter implant.more » A dosimetric and radiobiological perspective will help point out the evolution in breast brachytherapy, both in terms of devices and the protocols/clinical trials under which these devices are used. Improvements in imaging, delivery modalities and convenience are among the factors driving the ultrashort fractionation schedules but our understanding of both local control and toxicities associated with various treatments is lagging. A comparison between various schedules, from a radiobiological perspective, will be given together with a critical analysis of the issues. to review and understand the evolution and development of APBI using brachytherapy methods to understand the basis and limitations of radio-biological ‘equivalence’ between fractionation schedules to review commonly used and proposed fractionation schedules Intra-operative breast brachytherapy: Is one stop shopping best?- Bruce Libby, PhD. University of Virginia A review of intraoperative breast brachytherapy will be presented, including the Targit-A and other trials that have used electronic brachytherapy. More modern approaches, in which the lumpectomy procedure is integrated into an APBI workflow, will also be discussed. Learning Objectives: To review past and current clinical trials for IORT To discuss lumpectomy-scan-plan-treat workflow for IORT.« less

Variation in uterus position prior to brachytherapy of the cervix: A case report.

PubMed

Georgescu, M T; Anghel, R

2017-01-01

Rationale: brachytherapy is administered in the treatment of patients with locally advanced cervical cancer following chemoradiotherapy. Lack of local anatomy evaluation prior to this procedure might lead to the selection of an inappropriate brachytherapy applicator, increasing the risk of side effects (e.g. uterus perforation, painful procedure ...). Objective: To assess the movement of the uterus and cervix prior to brachytherapy in patients with gynecological cancer, in order to select the proper type of brachytherapy applicator. Also we wanted to promote the replacement of the plain X-ray brachytherapy with the image-guided procedure. Methods and results: We presented the case of a 41-year-old female diagnosed with a biopsy that was proven cervical cancer stage IIIB. At diagnosis, the imaging studies identified an anteverted uterus. The patient underwent preoperative chemoradiotherapy. Prior to brachytherapy, the patient underwent a pelvic magnetic resonance imaging (MRI), which identified a displacement of the uterus in the retroverted position. Discussion: A great variety of brachytherapy applicators is available nowadays. Major changes in uterus position and lack of evaluation prior to brachytherapy might lead to a higher rate of incidents during this procedure. Also, by using orthogonal simulation and bidimensional (2D) treatment planning, brachytherapy would undoubtedly fail to treat the remaining tumoral tissue. This is the reason why we proposed the implementation of a prior imaging of the uterus and computed tomography (CT)/ MRI-based simulation in the brachytherapy procedure. Abbreviations: MRI = magnetic resonance imaging, CT = computed tomography, CTV = clinical target volume, DVH = dose-volume histogram, EBRT = external beam radiotherapy, GTV = gross tumor volume, Gy = Gray (unit), ICRU = International Commission of Radiation Units, IGRT = image guided radiotherapy, IM = internal margin, IMRT = image modulated radiotherapy, ITV = internal target volume, MRI = magnetic resonance imaging, OAR = organs at risk, PTV = planning target volume, QUANTEC = Quantitative Analyses of Normal Tissue Effects in the Clinic.

SU-F-T-06: Development of a Formalism for Practical Dose Measurements in Brachytherapy in the German Standard DIN 6803

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hensley, F; Chofor, N; Schoenfeld, A

2016-06-15

Purpose: In the steep dose gradients in the vicinity of a radiation source and due to the properties of the changing photon spectra, dose measurements in Brachytherapy usually have large uncertainties. Working group DIN 6803-3 is presently discussing recommendations for practical brachytherapy dosimetry incorporating recent theoretical developments in the description of brachytherapy radiation fields as well as new detectors and phantom materials. The goal is to prepare methods and instruments to verify dose calculation algorithms and for clinical dose verification with reduced uncertainties. Methods: After analysis of the distance dependent spectral changes of the radiation field surrounding brachytherapy sources, themore » energy dependent response of typical brachytherapy detectors was examined with Monte Carlo simulations. A dosimetric formalism was developed allowing the correction of their energy dependence as function of source distance for a Co-60 calibrated detector. Water equivalent phantom materials were examined with Monte Carlo calculations for their influence on brachytherapy photon spectra and for their water equivalence in terms of generating equivalent distributions of photon spectra and absorbed dose to water. Results: The energy dependence of a detector in the vicinity of a brachytherapy source can be described by defining an energy correction factor kQ for brachytherapy in the same manner as in existing dosimetry protocols which incorporates volume averaging and radiation field distortion by the detector. Solid phantom materials were identified which allow precise positioning of a detector together with small correctable deviations from absorbed dose to water. Recommendations for the selection of detectors and phantom materials are being developed for different measurements in brachytherapy. Conclusion: The introduction of kQ for brachytherapy sources may allow more systematic and comparable dose measurements. In principle, the corrections can be verified or even determined by measurement in a water phantom and comparison with dose distributions calculated using the TG43 dosimetry formalism. Project is supported by DIN Deutsches Institut fuer Normung.« less

Ocular Response of Choroidal Melanoma With Monosomy 3 Versus Disomy 3 After Iodine-125 Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marathe, Omkar S.; Wu, Jeffrey; Lee, Steve P.

2011-11-15

Purpose: To report the ocular response of choroidal melanoma with monosomy 3 vs. disomy 3 after {sup 125}I brachytherapy. Methods and Materials: We evaluated patients with ciliochoroidal melanoma managed with fine needle aspiration biopsy immediately before plaque application for {sup 125}I brachytherapy between January 1, 2005 and December 31, 2008. Patients with (1) cytopathologic diagnosis of melanoma, (2) melanoma chromosome 3 status identified by fluorescence in situ hybridization, and (3) 6 or more months of follow-up after brachytherapy were sorted by monosomy 3 vs. disomy 3 and compared by Kruskal-Wallis test. Results: Among 40 ciliochoroidal melanomas (40 patients), 15 hadmore » monosomy 3 and 25 had disomy 3. Monosomy 3 melanomas had a median greatest basal diameter of 12.00 mm and a median tumor thickness of 6.69 mm before brachytherapy; at a median of 1.75 years after brachytherapy, median thickness was 3.10 mm. Median percentage decrease in tumor thickness was 48.3%. Disomy 3 melanomas had a median greatest basal diameter of 10.00 mm and median tumor thickness of 3.19 mm before brachytherapy; at a median of 2.00 years after brachytherapy, median tumor thickness was 2.37 mm. The median percentage decrease in tumor thickness was 22.7%. Monosomy 3 melanomas were statistically greater in size than disomy 3 melanomas (p < 0.001) and showed a greater decrease in tumor thickness after brachytherapy (p = 0.006). Conclusion: In this study, ciliochoroidal melanomas with monosomy 3 were significantly greater in size than disomy 3 melanoma and showed a significantly greater decrease in thickness at a median of 1.75 years after brachytherapy. The greater decrease in monosomy 3 melanoma thickness after brachytherapy is consistent with other malignancies in which more aggressive pathology has been shown to be associated with a greater initial response to radiotherapy.« less

Minimal percentage of dose received by 90% of the urethra (%UD90) is the most significant predictor of PSA bounce in patients who underwent low-dose-rate brachytherapy (LDR-brachytherapy) for prostate cancer.

PubMed

Tanaka, Nobumichi; Asakawa, Isao; Fujimoto, Kiyohide; Anai, Satoshi; Hirayama, Akihide; Hasegawa, Masatoshi; Konishi, Noboru; Hirao, Yoshihiko

2012-09-14

To clarify the significant clinicopathological and postdosimetric parameters to predict PSA bounce in patients who underwent low-dose-rate brachytherapy (LDR-brachytherapy) for prostate cancer. We studied 200 consecutive patients who received LDR-brachytherapy between July 2004 and November 2008. Of them, 137 patients did not receive neoadjuvant or adjuvant androgen deprivation therapy. One hundred and forty-two patients were treated with LDR-brachytherapy alone, and 58 were treated with LDR-brachytherapy in combination with external beam radiation therapy. The cut-off value of PSA bounce was 0.1 ng/mL. The incidence, time, height, and duration of PSA bounce were investigated. Clinicopathological and postdosimetric parameters were evaluated to elucidate independent factors to predict PSA bounce in hormone-naïve patients who underwent LDR-brachytherapy alone. Fifty patients (25%) showed PSA bounce and 10 patients (5%) showed PSA failure. The median time, height, and duration of PSA bounce were 17 months, 0.29 ng/mL, and 7.0 months, respectively. In 103 hormone-naïve patients treated with LDR-brachytherapy alone, and univariate Cox proportional regression hazard model indicated that age and minimal percentage of the dose received by 30% and 90% of the urethra were independent predictors of PSA bounce. With a multivariate Cox proportional regression hazard model, minimal percentage of the dose received by 90% of the urethra was the most significant parameter of PSA bounce. Minimal percentage of the dose received by 90% of the urethra was the most significant predictor of PSA bounce in hormone-naïve patients treated with LDR-brachytherapy alone.

Recommendations of the Spanish brachytherapy group (GEB) of Spanish Society of Radiation Oncology (SEOR) and the Spanish Society of Medical Physics (SEFM) for high-dose rate (HDR) non melanoma skin cancer brachytherapy.

PubMed

Rodríguez, S; Arenas, M; Gutierrez, C; Richart, J; Perez-Calatayud, J; Celada, F; Santos, M; Rovirosa, A

2018-04-01

Clinical indications of brachytherapy in non-melanoma skin cancers, description of applicators and dosimetry recommendations are described based on the literature review, clinical practice and experience of Spanish Group of Brachytherapy and Spanish Society of Medical Physics reported in the XIV Annual Consensus Meeting on Non Melanoma Skin Cancer Brachytherapy held in Benidorm, Alicante (Spain) on October 21st, 2016. All the recommendations for which consensus was achieved are highlighted in blue. Regular and small surfaces may be treated with Leipzig, Valencia, flap applicators or electronic brachytherapy (EBT). For irregular surfaces, customized molds or interstitial implants should be employed. The dose is prescribed at a maximum depth of 3-4 mm of the clinical target volume/planning target volume (CTV/PTV) in all cases except in flaps or molds in which 5 mm is appropriate. Interstitial brachytherapy should be used for CTV/PTV >5 mm. Different total doses and fraction sizes are used with very similar clinical and toxicity results. Hypofractionation is very useful twice or 3 times a week, being comfortable for patients and practical for Radiotherapy Departments. In interstitial brachytherapy 2 fractions twice a day are applied.

Brachytherapy in Head and Neck Cancers: "Are We Doing It or Are We Done with It".

PubMed

Kirthi Koushik, A S; Alva, Ram Charith

2018-06-01

We performed an e-Survey and reviewed the literature on the prevalence of use of brachytherapy in head and neck cancers in order to understand the patterns of care and probable application of this modality. A five-point questionnaire was prepared and sent to 300 oncologists through a web-based survey engine. This was done in preparation for my lecture on "Ongoing Research and Potential Research Avenues" in IBSCON held in Chennai in August 2016. SPSS software was used for the statistical analysis. Of a total of 300 emails that were sent out for the survey, 120 replies were received, which is 40%. Among the results of various questions, (i) 65% of the oncologists felt that there were > 300 ongoing studies in brachytherapy and out of them only 10-20 were on head and neck brachytherapy; (ii) 58% of the responders felt that external beam radiotherapy (EBRT) advances followed by lack of training and experience are the reasons for declining role of brachytherapy; (iii) among the responders, numbers of head and neck brachytherapy performed stand third after gynecological and breast brachytherapy. This survey shows that brachytherapy in head and neck cancers is an essential tool, but seldom practiced. If no path-breaking event happens, we may be dealing with it as a dying art.

SU-F-J-157: Effect of Contouring Uncertainty in Post Implant Dosimetry of Low-Dose-Rate Prostate Permanent Seed Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mashouf, S; Merino, T; Ravi, A

Purpose: There is strong evidence relating post-implant dosimetry for low-dose-rate (LDR) prostate seed brachytherapy to local control rates. The delineation of the prostate on CT images, however, represents a challenge due to the lack of soft tissue contrast in order to identify the prostate borders. This study aims at quantifying the sensitivity of clinically relevant dosimetric parameters to uncertainty in the contouring of prostate. Methods: CT images, post-op plans and contours of a cohort of patients (n=43) (low risk=55.8%, intermediate risk=39.5%, high risk=4.7%), who had received prostate seed brachytherapy, were imported into MIM Symphony treatment planning system. The prostate contoursmore » in post-implant CT images were expanded/contracted uniformly for margins of ±1.00 mm, ±2.00 mm, ±3.00 mm, ±4.00 mm and ±5.00 mm. The values for V100 and D90 were extracted from Dose Volume Histograms for each contour and compared. Results: Significant changes were observed in the values of D90 and V100 as well as the number of suboptimal plans for expansion or contraction margins of only few millimeters. Evaluation of coverage based on D90 was found to be less sensitive to expansion errors compared to V100. D90 led to a lower number of implants incorrectly identified with insufficient coverage for expanded contours which increases the accuracy of post-implant QA using CT images compared to V100. Conclusion: In order to establish a successful post implant QA for LDR prostate seed brachytherapy, it is necessary to identify the low and high thresholds of important dose metrics of the target volume such as D90 and V100. Since these parameters are sensitive to target volume definition, accurate identification of prostate borders would help to improve accuracy and predictive value of the post-implant QA process. In this respect, use of imaging modalities such as MRI where prostate is well delineated should prove useful.« less

Thermal dosimetry analysis combined with patient-specific thermal modeling of clinical interstitial ultrasound hyperthermia integrated within HDR brachytherapy for treatment of locally advanced prostate cancer

NASA Astrophysics Data System (ADS)

Salgaonkar, Vasant A.; Wootton, Jeff; Prakash, Punit; Scott, Serena; Hsu, I. C.; Diederich, Chris J.

2017-03-01

This study presents thermal dosimetry analysis from clinical treatments where ultrasound hyperthermia (HT) was administered following high-dose rate (HDR) brachytherapy treatment for locally advanced prostate cancer as part of a clinical pilot study. HT was administered using ultrasound applicators from within multiple 13-g brachytherapy catheters implanted along the posterior periphery of the prostate. The heating applicators were linear arrays of sectored tubular transducers (˜7 MHz), with independently powered array elements enabling energy deposition with 3D spatial control. Typical heat treatments employed time-averaged peak acoustic intensities of 1 - 3 W/cm2 and lasted for 60 - 70 minutes. Throughout the treatments, temperatures at multiple points were monitored using multi-junction thermocouples, placed within available brachytherapy catheters throughout mid-gland prostate and identified as the hyperthermia target volume (HTV). Clinical constraints allowed placement of 8 - 12 thermocouple sensors in the HTV and patient-specific 3D thermal modeling based on finite element methods (FEM) was used to supplement limited thermometry. Patient anatomy, heating device positions, orientations, and thermometry junction locations were obtained from patient CT scans and HDR and hyperthermia planning software. The numerical models utilized the applied power levels recorded during the treatments. Tissue properties such as perfusion and acoustic absorption were varied within physiological ranges such that squared-errors between measured and simulated temperatures were minimized. This data-fitting was utilized for 6 HT treatments to estimate volumetric temperature distributions achieved in the HTV and surrounding anatomy devoid of thermocouples. For these treatments, the measured and simulated T50 values in the hyperthermia target volume (HTV) were between 40.1 - 43.9 °C and 40.3 - 44.9 °C, respectively. Maximum temperatures between 46.8 - 49.8 °C were measured during these treatments and the corresponding range obtained from simulation was 47.3 - 51.1 °C. Based on the simulations, the maximum temperatures in the bladder and the rectum were below 41.7 °C and 41.1 °C, respectively.

Comparison of organ doses for patients undergoing balloon brachytherapy of the breast with HDR 192Ir or electronic sources using Monte Carlo simulations in a heterogeneous human phantom1

PubMed Central

Mille, Matthew M.; Xu, X. George; Rivard, Mark J.

2010-01-01

Purpose: Accelerated partial breast irradiation via interstitial balloon brachytherapy is a fast and effective treatment method for certain early stage breast cancers. The radiation can be delivered using a conventional high-dose rate (HDR) 192Ir gamma-emitting source or a novel electronic brachytherapy (eBx) source which uses lower energy x rays that do not penetrate as far within the patient. A previous study [A. Dickler, M. C. Kirk, N. Seif, K. Griem, K. Dowlatshahi, D. Francescatti, and R. A. Abrams, “A dosimetric comparison of MammoSite high-dose-rate brachytherapy and Xoft Axxent electronic brachytherapy,” Brachytherapy 6, 164–168 (2007)] showed that the target dose is similar for HDR 192Ir and eBx. This study compares these sources based on the dose received by healthy organs and tissues away from the treatment site. Methods: A virtual patient with left breast cancer was represented by a whole-body, tissue-heterogeneous female voxel phantom. Monte Carlo methods were used to calculate the dose to healthy organs in a virtual patient undergoing balloon brachytherapy of the left breast with HDR 192Ir or eBx sources. The dose-volume histograms for a few organs which received large doses were also calculated. Additional simulations were performed with all tissues in the phantom defined as water to study the effect of tissue inhomogeneities. Results: For both HDR 192Ir and eBx, the largest mean organ doses were received by the ribs, thymus gland, left lung, heart, and sternum which were close to the brachytherapy source in the left breast. eBx yielded mean healthy organ doses that were more than a factor of ∼1.4 smaller than for HDR 192Ir for all organs considered, except for the three closest ribs. Excluding these ribs, the average and median dose-reduction factors were ∼28 and ∼11, respectively. The volume distribution of doses in nearby soft tissue organs that were outside the PTV were also improved with eBx. However, the maximum dose to the closest rib with the eBx source was 5.4 times greater than that of the HDR 192Ir source. The ratio of tissue-to-water maximum rib dose for the eBx source was ∼5. Conclusions: The results of this study indicate that eBx may offer lower toxicity to most healthy tissues, except nearby bone. TG-43 methods have a tendency to underestimate dose to bone, especially the ribs. Clinical studies evaluating the negative health effects caused by irradiating healthy organs are needed so that physicians can better understand when HDR 192Ir or eBx might best benefit a patient. PMID:20229875

10 CFR 35.415 - Safety precautions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Safety precautions. 35.415 Section 35.415 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.415 Safety precautions. (a... his or her designee, and an authorized user as soon as possible if the patient or human research...

10 CFR 35.410 - Safety instruction.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Safety instruction. 35.410 Section 35.410 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.410 Safety instruction. In... designee, and an authorized user if the patient or the human research subject has a medical emergency or...

Air kerma and absorbed dose standards for reference dosimetry in brachytherapy

PubMed Central

2014-01-01

This article reviews recent developments in primary standards for the calibration of brachytherapy sources, with an emphasis on the currently most common photon-emitting radionuclides. The introduction discusses the need for reference dosimetry in brachytherapy in general. The following section focuses on the three main quantities, i.e. reference air kerma rate, air kerma strength and absorbed dose rate to water, which are currently used for the specification of brachytherapy photon sources and which can be realized with primary standards from first principles. An overview of different air kerma and absorbed dose standards, which have been independently developed by various national metrology institutes over the past two decades, is given in the next two sections. Other dosimetry techniques for brachytherapy will also be discussed. The review closes with an outlook on a possible transition from air kerma to absorbed dose to water-based calibrations for brachytherapy sources in the future. PMID:24814696

Prostate Brachytherapy Seed Reconstruction with Gaussian Blurring and Optimal Coverage Cost

PubMed Central

Lee, Junghoon; Liu, Xiaofeng; Jain, Ameet K.; Song, Danny Y.; Burdette, E. Clif; Prince, Jerry L.; Fichtinger, Gabor

2009-01-01

Intraoperative dosimetry in prostate brachytherapy requires localization of the implanted radioactive seeds. A tomosynthesis-based seed reconstruction method is proposed. A three-dimensional volume is reconstructed from Gaussian-blurred projection images and candidate seed locations are computed from the reconstructed volume. A false positive seed removal process, formulated as an optimal coverage problem, iteratively removes “ghost” seeds that are created by tomosynthesis reconstruction. In an effort to minimize pose errors that are common in conventional C-arms, initial pose parameter estimates are iteratively corrected by using the detected candidate seeds as fiducials, which automatically “focuses” the collected images and improves successive reconstructed volumes. Simulation results imply that the implanted seed locations can be estimated with a detection rate of ≥ 97.9% and ≥ 99.3% from three and four images, respectively, when the C-arm is calibrated and the pose of the C-arm is known. The algorithm was also validated on phantom data sets successfully localizing the implanted seeds from four or five images. In a Phase-1 clinical trial, we were able to localize the implanted seeds from five intraoperative fluoroscopy images with 98.8% (STD=1.6) overall detection rate. PMID:19605321

The dosimetry of brachytherapy-induced erectile dysfunction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merrick, Gregory S.; Butler, Wayne M

2003-12-31

There is emerging evidence that brachytherapy-induced erectile dysfunction (ED) is technique-related and may be minimized by careful attention to source placement. Herein, we review the relationship between radiation doses to the prostate gland/surrounding structures and the development of brachytherapy-induced ED. The permanent prostate brachytherapy literature was reviewed using MEDLINE searches to ensure completeness. Although the site-specific structure associated with brachytherapy-induced ED remains unknown, there is an increasing body of data implicating the proximal penis. With day 0 CT-based dosimetry, the dose to 50% (D{sub 50}) and 25% (D{sub 25}) of the bulb of the penis should be maintained below 40%more » and 60% mPD, respectively, while the crura D{sub 50} should be maintained below 28% mPD to maximize post-brachytherapy potency. To date, there is no data to suggest that either radiation doses to the neurovascular bundles or choice of isotope is associated with brachytherapy-induced ED, while conflicting data has been reported regarding radiation dose to the prostate and the use of supplemental external beam radiation therapy. Although the etiology of brachytherapy-induced ED is likely multifactorial, the available data supports the proximal penis as an important site-specific structure. Refinements in implant technique, including preplanning and intraoperative seed placement, will result in lower radiation doses to the proximal penis with potential improvement in potency preservation.« less

Postlumpectomy Focal Brachytherapy for Simultaneous Treatment of Surgical Cavity and Draining Lymph Nodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hrycushko, Brian A.; Li Shihong; Shi Chengyu

2011-03-01

Purpose: The primary objective was to investigate a novel focal brachytherapy technique using lipid nanoparticle (liposome)-carried {beta}-emitting radionuclides (rhenium-186 [{sup 186}Re]/rhenium-188 [{sup 188}Re]) to simultaneously treat the postlumpectomy surgical cavity and draining lymph nodes. Methods and Materials: Cumulative activity distributions in the lumpectomy cavity and lymph nodes were extrapolated from small animal imaging and human lymphoscintigraphy data. Absorbed dose calculations were performed for lumpectomy cavities with spherical and ellipsoidal shapes and lymph nodes within human subjects by use of the dose point kernel convolution method. Results: Dose calculations showed that therapeutic dose levels within the lumpectomy cavity wall can covermore » 2- and 5-mm depths for {sup 186}Re and {sup 188}Re liposomes, respectively. The absorbed doses at 1 cm sharply decreased to only 1.3% to 3.7% of the doses at 2 mm for {sup 186}Re liposomes and 5 mm for {sup 188}Re liposomes. Concurrently, the draining sentinel lymph nodes would receive a high focal therapeutic absorbed dose, whereas the average dose to 1 cm of surrounding tissue received less than 1% of that within the nodes. Conclusions: Focal brachytherapy by use of {sup 186}Re/{sup 188}Re liposomes was theoretically shown to be capable of simultaneously treating the lumpectomy cavity wall and draining sentinel lymph nodes with high absorbed doses while significantly lowering dose to surrounding healthy tissue. In turn, this allows for dose escalation to regions of higher probability of containing residual tumor cells after lumpectomy while reducing normal tissue complications.« less

Comparison of TG‐43 dosimetric parameters of brachytherapy sources obtained by three different versions of MCNP codes

PubMed Central

Zaker, Neda; Sina, Sedigheh; Koontz, Craig; Meigooni1, Ali S.

2016-01-01

Monte Carlo simulations are widely used for calculation of the dosimetric parameters of brachytherapy sources. MCNP4C2, MCNP5, MCNPX, EGS4, EGSnrc, PTRAN, and GEANT4 are among the most commonly used codes in this field. Each of these codes utilizes a cross‐sectional library for the purpose of simulating different elements and materials with complex chemical compositions. The accuracies of the final outcomes of these simulations are very sensitive to the accuracies of the cross‐sectional libraries. Several investigators have shown that inaccuracies of some of the cross section files have led to errors in  125I and  103Pd parameters. The purpose of this study is to compare the dosimetric parameters of sample brachytherapy sources, calculated with three different versions of the MCNP code — MCNP4C, MCNP5, and MCNPX. In these simulations for each source type, the source and phantom geometries, as well as the number of the photons, were kept identical, thus eliminating the possible uncertainties. The results of these investigations indicate that for low‐energy sources such as  125I and  103Pd there are discrepancies in gL(r) values. Discrepancies up to 21.7% and 28% are observed between MCNP4C and other codes at a distance of 6 cm for  103Pd and 10 cm for  125I from the source, respectively. However, for higher energy sources, the discrepancies in gL(r) values are less than 1.1% for  192Ir and less than 1.2% for  137Cs between the three codes. PACS number(s): 87.56.bg PMID:27074460

New (125)I brachytherapy source IsoSeed I25.S17plus: Monte Carlo dosimetry simulation and comparison to sources of similar design.

PubMed

Pantelis, Evaggelos; Papagiannis, Panagiotis; Anagnostopoulos, Giorgos; Baltas, Dimos

2013-12-01

To determine the relative dose rate distribution around the new (125)I brachytherapy source IsoSeed I25.S17plus and report results in a form suitable for clinical use. Results for the new source are also compared to corresponding results for other commercially available (125)I sources of similar design. Monte Carlo simulations were performed using the MCNP5 v.1.6 general purpose code. The model of the new source was prepared from information provided by the manufacturer and verified by imaging a sample of ten non-radioactive sources. Corresponding simulations were also performed for the 6711 (125)I brachytherapy source, using updated geometric information presented recently in the literature. The uncertainty of the dose distribution around the new source, as well as the dosimetric quantities derived from it according to the Task Group 43 formalism, were determined from the standard error of the mean of simulations for a sample of fifty source models. These source models were prepared by randomly selecting values of geometric parameters from uniform distributions defined by manufacturer stated tolerances. Results are presented in the form of the quantities defined in the update of the Task Group 43 report, as well as a relative dose rate table in Cartesian coordinates. The dose rate distribution of the new source is comparable to that of sources of similar design (IsoSeed I25.S17, Oncoseed 6711, SelectSeed 130.002, Advantage IAI-125A, I-Seed AgX100, Thinseed 9011). Noticeable differences were observed only for the IsoSeed I25.S06 and Best 2301 sources.

Estimating statistical uncertainty of Monte Carlo efficiency-gain in the context of a correlated sampling Monte Carlo code for brachytherapy treatment planning with non-normal dose distribution.

PubMed

Mukhopadhyay, Nitai D; Sampson, Andrew J; Deniz, Daniel; Alm Carlsson, Gudrun; Williamson, Jeffrey; Malusek, Alexandr

2012-01-01

Correlated sampling Monte Carlo methods can shorten computing times in brachytherapy treatment planning. Monte Carlo efficiency is typically estimated via efficiency gain, defined as the reduction in computing time by correlated sampling relative to conventional Monte Carlo methods when equal statistical uncertainties have been achieved. The determination of the efficiency gain uncertainty arising from random effects, however, is not a straightforward task specially when the error distribution is non-normal. The purpose of this study is to evaluate the applicability of the F distribution and standardized uncertainty propagation methods (widely used in metrology to estimate uncertainty of physical measurements) for predicting confidence intervals about efficiency gain estimates derived from single Monte Carlo runs using fixed-collision correlated sampling in a simplified brachytherapy geometry. A bootstrap based algorithm was used to simulate the probability distribution of the efficiency gain estimates and the shortest 95% confidence interval was estimated from this distribution. It was found that the corresponding relative uncertainty was as large as 37% for this particular problem. The uncertainty propagation framework predicted confidence intervals reasonably well; however its main disadvantage was that uncertainties of input quantities had to be calculated in a separate run via a Monte Carlo method. The F distribution noticeably underestimated the confidence interval. These discrepancies were influenced by several photons with large statistical weights which made extremely large contributions to the scored absorbed dose difference. The mechanism of acquiring high statistical weights in the fixed-collision correlated sampling method was explained and a mitigation strategy was proposed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Utilization of prostate brachytherapy for low risk prostate cancer: Is the decline overstated?

PubMed

Safdieh, Joseph; Wong, Andrew; Weiner, Joseph P; Schwartz, David; Schreiber, David

2016-08-01

Several prior studies have suggested that brachytherapy utilization has markedly decreased, coinciding with the recent increased utilization of intensity modulated radiation therapy, as well as an increase in urologist-owned centers. We sought to investigate the brachytherapy utilization in a large, hospital-based registry. Men with prostate cancer diagnosed between 2004-2012 and treated with either external beam radiation and/or prostate brachytherapy were abstracted from the National Cancer Database. In order to be included, men had to be clinically staged as T1c-T2aNx-0Mx-0, Gleason 6, PSA ≤ 10.0 ng/ml. Descriptive statistics were used to analyze brachytherapy utilization over time and were compared via χ(2). Multivariate logistic regression was used to assess for covariables associated with increased brachytherapy usage. There were 89,413 men included in this study, of which 37,054 (41.6%) received only external beam radiation, and 52,089 (58.4%) received prostate brachytherapy. The use of brachytherapy declined over time from 62.9% in 2004 to 51.3% in 2012 (p < 0.001). This decline was noted in both academic facilities (60.8% in 2004 to 47.0% in 2012, p < 0.001) as well as in non-academic facilities (63.7% in 2004 to 53.0% in 2012, p < 0.001). The decline was more pronounced in patients who lived closer to treatment facilities than those who lived further. The use of intensity modulated radiation therapy increased during this same time period from 18.4% in 2004 to 38.2% in 2012 (p < 0.001). On multivariate analysis, treatment at an academic center, increasing age, decreasing distance from the treatment center, and years of diagnosis from 2006-2012 were significantly associated with reduced brachytherapy usage. In this hospital-based registry, prostate brachytherapy usage has declined for low risk prostate cancer as intensity modulated radiation therapy usage has increased. However, it still remains the treatment of choice for 51.3% of patients as of 2012.

MO-E-BRD-01: Is Non-Invasive Image-Guided Breast Brachytherapy Good?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiatt, J.

2015-06-15

Is Non-invasive Image-Guided Breast Brachytherapy Good? – Jess Hiatt, MS Non-invasive Image-Guided Breast Brachytherapy (NIBB) is an emerging therapy for breast boost treatments as well as Accelerated Partial Breast Irradiation (APBI) using HDR surface breast brachytherapy. NIBB allows for smaller treatment volumes while maintaining optimal target coverage. Considering the real-time image-guidance and immobilization provided by the NIBB modality, minimal margins around the target tissue are necessary. Accelerated Partial Breast Irradiation in brachytherapy: is shorter better? - Dorin Todor, PhD VCU A review of balloon and strut devices will be provided together with the origins of APBI: the interstitial multi-catheter implant.more » A dosimetric and radiobiological perspective will help point out the evolution in breast brachytherapy, both in terms of devices and the protocols/clinical trials under which these devices are used. Improvements in imaging, delivery modalities and convenience are among the factors driving the ultrashort fractionation schedules but our understanding of both local control and toxicities associated with various treatments is lagging. A comparison between various schedules, from a radiobiological perspective, will be given together with a critical analysis of the issues. to review and understand the evolution and development of APBI using brachytherapy methods to understand the basis and limitations of radio-biological ‘equivalence’ between fractionation schedules to review commonly used and proposed fractionation schedules Intra-operative breast brachytherapy: Is one stop shopping best?- Bruce Libby, PhD. University of Virginia A review of intraoperative breast brachytherapy will be presented, including the Targit-A and other trials that have used electronic brachytherapy. More modern approaches, in which the lumpectomy procedure is integrated into an APBI workflow, will also be discussed. Learning Objectives: To review past and current clinical trials for IORT To discuss lumpectomy-scan-plan-treat workflow for IORT.« less

High brachytherapy doses can counteract hypoxia in cervical cancer—a modelling study

NASA Astrophysics Data System (ADS)

Lindblom, Emely; Dasu, Alexandru; Beskow, Catharina; Toma-Dasu, Iuliana

2017-01-01

Tumour hypoxia is a well-known adverse factor for the outcome of radiotherapy. For cervical tumours in particular, several studies indicate large variability in tumour oxygenation. However, clinical evidence shows that the management of cervical cancer including brachytherapy leads to high rate of success. It was the purpose of this study to investigate whether the success of brachytherapy for cervical cancer, seemingly regardless of oxygenation status, could be explained by the characteristics of the brachytherapy dose distributions. To this end, a previously used in silico model of tumour oxygenation and radiation response was further developed to simulate the treatment of cervical cancer employing a combination of external beam radiotherapy and intracavitary brachytherapy. Using a clinically-derived brachytherapy dose distribution and assuming a homogeneous dose delivered by external radiotherapy, cell survival was assessed on voxel level by taking into account the variation of sensitivity with oxygenation as well as the effects of repair, repopulation and reoxygenation during treatment. Various scenarios were considered for the conformity of the brachytherapy dose distribution to the hypoxic region in the target. By using the clinically-prescribed brachytherapy dose distribution and varying the total dose delivered with external beam radiotherapy in 25 fractions, the resulting values of the dose for 50% tumour control, D 50, were in agreement with clinically-observed values for high cure rates if fast reoxygenation was assumed. The D 50 was furthermore similar for the different degrees of conformity of the brachytherapy dose distribution to the tumour, regardless of whether the hypoxic fraction was 10%, 25%, or 40%. To achieve 50% control with external RT only, a total dose of more than 70 Gy in 25 fractions would be required for all cases considered. It can thus be concluded that the high doses delivered in brachytherapy can counteract the increased radioresistance caused by hypoxia if fast reoxygenation is assumed.

MO-E-BRD-02: Accelerated Partial Breast Irradiation in Brachytherapy: Is Shorter Better?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Todor, D.

2015-06-15

Is Non-invasive Image-Guided Breast Brachytherapy Good? – Jess Hiatt, MS Non-invasive Image-Guided Breast Brachytherapy (NIBB) is an emerging therapy for breast boost treatments as well as Accelerated Partial Breast Irradiation (APBI) using HDR surface breast brachytherapy. NIBB allows for smaller treatment volumes while maintaining optimal target coverage. Considering the real-time image-guidance and immobilization provided by the NIBB modality, minimal margins around the target tissue are necessary. Accelerated Partial Breast Irradiation in brachytherapy: is shorter better? - Dorin Todor, PhD VCU A review of balloon and strut devices will be provided together with the origins of APBI: the interstitial multi-catheter implant.more » A dosimetric and radiobiological perspective will help point out the evolution in breast brachytherapy, both in terms of devices and the protocols/clinical trials under which these devices are used. Improvements in imaging, delivery modalities and convenience are among the factors driving the ultrashort fractionation schedules but our understanding of both local control and toxicities associated with various treatments is lagging. A comparison between various schedules, from a radiobiological perspective, will be given together with a critical analysis of the issues. to review and understand the evolution and development of APBI using brachytherapy methods to understand the basis and limitations of radio-biological ‘equivalence’ between fractionation schedules to review commonly used and proposed fractionation schedules Intra-operative breast brachytherapy: Is one stop shopping best?- Bruce Libby, PhD. University of Virginia A review of intraoperative breast brachytherapy will be presented, including the Targit-A and other trials that have used electronic brachytherapy. More modern approaches, in which the lumpectomy procedure is integrated into an APBI workflow, will also be discussed. Learning Objectives: To review past and current clinical trials for IORT To discuss lumpectomy-scan-plan-treat workflow for IORT.« less

WE-E-BRD-01: HDR Brachytherapy I: Overview of Clinical Application and QA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, B; Showalter, T

2014-06-15

With the increased usage of high dose rate (HDR) brachytherapy and the introduction of dedicated image guided brachytherapy suites, it is necessary to review the processes and procedures associated with safely delivering these treatments in the expedited time scales that dedicated treatment suites afford. The speakers will present the clinical aspects of switching from LDR to HDR treatments, including guidelines for patient selection, and the clinical outcomes comparing LDR to HDR. The speakers will also discuss the HDR treatment process itself, because the shortened clinical timeline involved with a streamlined scan/plan/treat workflow can introduce other issues. Safety and QA aspectsmore » involved with the streamlined process, including increased personnel required for parallel tasks, and possible interfering tasks causing delays in patient treatments will also be discussed. Learning Objectives: To understand the clinical aspects of HDR Brachytherapy, including common clinical indications, patient selection, and the evolving evidence in support of this therapeutic modality To review the current prominent clinical trials for HDR brachytherapy To interpret the established guidelines for HDR brachytherapy quality assurance for implementation into practical clinical settings. To introduce the basic requirements for image guided brachytherapy.« less

Temporal relationship between prostate brachytherapy and the diagnosis of colorectal cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gutman, Sarah A.; Merrick, Gregory S.; Butler, Wayne M.

2006-09-01

Purpose: To identify the location of pretreatment and posttreatment colorectal malignancies and posttreatment colorectal polyps in patients with clinically localized prostate cancer managed with brachytherapy. Methods and Materials: From April 1995 through July 2004, 1,351 consecutive patients underwent brachytherapy for clinical stage T1b-T3a (American Joint Committee on Cancer, 2002) prostate cancer. Supplemental external beam radiotherapy (XRT) was administered to 699 patients. The median follow-up was 4.6 years. Operative and pathology reports were reviewed for all patients with pretreatment and posttreatment colorectal cancer and posttreatment colorectal polyps. Multiple parameters were evaluated for the development of colorectal cancer or colorectal polyps. Results:more » Colorectal cancer was diagnosed in 23 and 25 patients before and after prostate brachytherapy, respectively. No differences were identified in the distribution of colorectal cancers either before or after treatment (3 and 4 rectal cancers in the pre- and postbrachytherapy cohorts). Thirty-five of the 48 colorectal cancers (73%) were diagnosed within 5 years of brachytherapy with a peak incidence 1 year after brachytherapy. One hundred ninety-two colorectal polyps were diagnosed after brachytherapy, 160 (83%) occurred within 4 years of brachytherapy, and only 27 (14%) were located in the rectum. In multivariate Cox regression analysis, prostate D{sub 9} (minimum percentage of the dose covering 90% of the target volume) predicted for posttreatment colorectal cancer. Rectal polyps were most closely related to patient age and percent positive biopsies, whereas sigmoid/colon polyps were best predicted by patient age, planning volume, and supplemental XRT. Conclusions: Colorectal cancer was diagnosed with equal frequency before and after brachytherapy with comparable geographic distributions. In addition, the vast majority of postbrachytherapy colorectal polyps were located beyond the confines of the rectum.« less

The perioperative charge equivalence of interstitial brachytherapy and radical prostatectomy with 1-year followup.

PubMed

Kohan, A D; Armenakas, N A; Fracchia, J A

2000-02-01

We compare the comprehensive 1-year charges in a consecutive group of patients undergoing radical prostatectomy and transperineal interstitial brachytherapy for clinically localized prostate cancer at a single urban institution. A total of 60 consecutive men with clinically localized prostate cancer (T1-T2, N0, M0) were treated during a 15-month period with radical prostatectomy or interstitial brachytherapy. Hospital and outpatient records were analyzed for each patient in regard to preoperative, operative and postoperative charges. Parameters included number of encounters, diagnostic and therapeutic interventions, hospitalization and operative charges, and followup visits, diagnostic tests and interventions for 1 year. All charge calculations were based arbitrarily on the 1996 Medicare fee schedule, factoring in the mandated global charge reimbursement period of 90 days for both procedures. Of the patients 38 underwent radical prostatectomy (prostatectomy group) and 22 underwent interstitial brachytherapy (brachytherapy group). The brachytherapy group was older with higher pretreatment serum prostate specific antigen and clinical stage disease, and more frequently received neoadjuvant hormonal therapy compared to the prostatectomy group. The 2 groups were similar in Gleason score and, when applicable, duration of neoadjuvant hormonal therapy. Preoperative charges were 15.3% lower for prostatectomy than for brachytherapy (not statistically significant). Conversely, operative charges for prostatectomy were 13.5% higher (p = 0.04). The major difference among preoperative, operative and postoperative charges was for those incurred postoperatively by the brachytherapy group, which were 56.0% higher than those for the prostatectomy group ($2,285.20 versus $1,007.20, p = 0.0004). Transperineal interstitial seed implantation is perceived by many as more cost-effective than radical prostatectomy for patients with clinically localized prostate cancer. We demonstrated that when such patients were followed for 1 year, the comprehensive charges for radical prostatectomy and interstitial brachytherapy were equivalent.

High versus low-dose rate brachytherapy for cervical cancer.

PubMed

Patankar, Sonali S; Tergas, Ana I; Deutsch, Israel; Burke, William M; Hou, June Y; Ananth, Cande V; Huang, Yongmei; Neugut, Alfred I; Hershman, Dawn L; Wright, Jason D

2015-03-01

Brachytherapy plays an important role in the treatment of cervical cancer. While small trials have shown comparable survival outcomes between high (HDR) and low-dose rate (LDR) brachytherapy, little data is available in the US. We examined the utilization of HDR brachytherapy and analyzed the impact of type of brachytherapy on survival for cervical cancer. Women with stages IB2-IVA cervical cancer treated with primary (external beam and brachytherapy) radiotherapy between 2003-2011 and recorded in the National Cancer Database (NCDB) were analyzed. Generalized linear mixed models and Cox proportional hazards regression were used to examine predictors of HDR brachytherapy use and the association between HDR use and survival. A total of 10,564 women including 2681 (25.4%) who received LDR and 7883 (74.6%) that received HDR were identified. Use of HDR increased from 50.2% in 2003 to 83.9% in 2011 (P<0.0001). In a multivariable model, year of diagnosis was the strongest predictor of use of HDR. While patients in the Northeast were more likely to receive HDR therapy, there were no other clinical or socioeconomic characteristics associated with receipt of HDR. In a multivariable Cox model, survival was similar between the HDR and LDR groups (HR=0.93; 95% CI 0.83-1.03). Similar findings were noted in analyses stratified by stage and histology. Kaplan-Meier analyses demonstrated no difference in survival based on type of brachytherapy for stage IIB (P=0.68), IIIB (P=0.17), or IVA (P=0.16) tumors. The use of HDR therapy has increased rapidly. Overall survival is similar for LDR and HDR brachytherapy. Copyright © 2015 Elsevier Inc. All rights reserved.

Survey of brachytherapy practice in the United States: a report of the Clinical Research Committee of the American Endocurietherapy Society.

PubMed

Nag, S; Owen, J B; Farnan, N; Pajak, T F; Martinez, A; Porter, A; Blasko, J; Harrison, L B

1995-01-01

To obtain reliable data on the extent of the brachytherapy practice in the United States by conducting a comprehensive survey of all facilities. The Clinical Research Committee of the AES surveyed all 1321 radiation oncology facilities identified in the Patterns of Care Study (PCS) of the American College of Radiology (ACR). Multiple mailings and follow-up were made to obtain a high response rate. Survey responders and nonresponders were compared using chi-square tests. Summary statistics were reported. Of the 1321 facilities, 1054 responded (80%). Hospital-based and larger facilities had a statistically significant higher rate of response. Brachytherapy was being performed at 819 facilities (the median number of procedures = 21-50). Two hundred and two facilities did no brachytherapy. The common isotopes used were 137Cs (705 facilities), 192Ir (585 facilities), 125I (236 facilities), and 131I (194 facilities). The common brachytherapy techniques used were intracavitary (751 facilities), interstitial (536 facilities), intraluminal (310 facilities), and plaques (148 facilities). Remote afterloaded brachytherapy was used at 205 centers as follows: high dose rate (HDR) (164), medium dose rate (MDR) (5), and low dose rate (LDR) (36). Computerized dosimetry was most commonly used (790 facilities), followed by Patterson-Parker (104 facilities) and Quimby (72 facilities). The common sites treated were cervix (701 facilities), endometrium (565 facilities), head and neck (354 facilities), and lung (344 facilities). Data regarding brachytherapy practice has been obtained from a large percentage (80%) of all facilities in the United States. The majority (78-81%) of radiation oncology facilities perform brachytherapy; however, its use is restricted to gynecological implants in many of these centers. The results from this survey will be used to develop a pattern of care study and data registry in brachytherapy.

High versus Low-Dose Rate Brachytherapy for Cervical Cancer

PubMed Central

Patankar, Sonali S.; Tergas, Ana I.; Deutsch, Israel; Burke, William M.; Hou, June Y.; Ananth, Cande V.; Huang, Yongmei; Neugut, Alfred I.; Hershman, Dawn L.; Wright, Jason D.

2015-01-01

Objectives Brachytherapy plays an important role in the treatment of cervical cancer. While small trials have shown comparable survival outcomes between high (HDR) and low-dose rate (LDR) brachytherapy, little data is available in the US. We examined the utilization of HDR brachytherapy and analyzed the impact of type of brachytherapy on survival for cervical cancer. Methods Women with stage IB2–IVA cervical cancer treated with primary (external beam and brachytherapy) radiotherapy between 2003–2011 and recorded in the National Cancer Database (NCDB) were analyzed. Generalized linear mixed models and Cox proportional hazards regression were used to examine predictors of HDR brachytherapy use and the association between HDR use and survival. Results A total of 10,564 women including 2681 (25.4%) who received LDR and 7883 (74.6%) that received HDR were identified. Use of HDR increased from 50.2% in 2003 to 83.9% in 2011 (P<0.0001). In a multivariable model, year of diagnosis was the strongest predictor of use of HDR. While patients in the Northeast were more likely to receive HDR therapy, there were no other clinical or socioeconomic characteristics associated with receipt of HDR. In a multivariable Cox model, survival was similar between the HDR and LDR groups (HR=0.93; 95% 0.83–1.03). Similar findings were noted in analyses stratified by stage and histology. Kaplan-Meier analyses demonstrated no difference in survival based on type of brachytherapy for stage IIB (P=0.68), IIIB (P=0.17), or IVA (P=0.16) tumors. Conclusions The use of HDR therapy has increased rapidly. Overall survival is similar for LDR and HDR brachytherapy. PMID:25575481

Image Guided Cervical Brachytherapy: 2014 Survey of the American Brachytherapy Society

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grover, Surbhi, E-mail: Surbhi.grover@uphs.upenn.edu; Harkenrider, Matthew M.; Cho, Linda P.

Purpose: To provide an update of the 2007 American brachytherapy survey on image-based brachytherapy, which showed that in the setting of treatment planning for gynecologic brachytherapy, although computed tomography (CT) was often used for treatment planning, most brachytherapists used point A for dose specification. Methods and Materials: A 45-question electronic survey on cervical cancer brachytherapy practice patterns was sent to all American Brachytherapy Society members and additional radiation oncologists and physicists based in the United States between January and September 2014. Responses from the 2007 survey and the present survey were compared using the χ{sup 2} test. Results: There weremore » 370 respondents. Of those, only respondents, not in training, who treat more than 1 cervical cancer patient per year and practice in the United States, were included in the analysis (219). For dose specification to the target (cervix and tumor), 95% always use CT, and 34% always use MRI. However, 46% use point A only for dose specification to the target. There was a lot of variation in parameters used for dose evaluation of target volume and normal tissues. Compared with the 2007 survey, use of MRI has increased from 2% to 34% (P<.0001) for dose specification to the target. Use of volume-based dose delineation to the target has increased from 14% to 52% (P<.0001). Conclusion: Although use of image-based brachytherapy has increased in the United States since the 2007 survey, there is room for further growth, particularly with the use of MRI. This increase may be in part due to educational initiatives. However, there is still significant heterogeneity in brachytherapy practice in the United States, and future efforts should be geared toward standardizing treatment.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Is Non-invasive Image-Guided Breast Brachytherapy Good? – Jess Hiatt, MS Non-invasive Image-Guided Breast Brachytherapy (NIBB) is an emerging therapy for breast boost treatments as well as Accelerated Partial Breast Irradiation (APBI) using HDR surface breast brachytherapy. NIBB allows for smaller treatment volumes while maintaining optimal target coverage. Considering the real-time image-guidance and immobilization provided by the NIBB modality, minimal margins around the target tissue are necessary. Accelerated Partial Breast Irradiation in brachytherapy: is shorter better? - Dorin Todor, PhD VCU A review of balloon and strut devices will be provided together with the origins of APBI: the interstitial multi-catheter implant.more » A dosimetric and radiobiological perspective will help point out the evolution in breast brachytherapy, both in terms of devices and the protocols/clinical trials under which these devices are used. Improvements in imaging, delivery modalities and convenience are among the factors driving the ultrashort fractionation schedules but our understanding of both local control and toxicities associated with various treatments is lagging. A comparison between various schedules, from a radiobiological perspective, will be given together with a critical analysis of the issues. to review and understand the evolution and development of APBI using brachytherapy methods to understand the basis and limitations of radio-biological ‘equivalence’ between fractionation schedules to review commonly used and proposed fractionation schedules Intra-operative breast brachytherapy: Is one stop shopping best?- Bruce Libby, PhD. University of Virginia A review of intraoperative breast brachytherapy will be presented, including the Targit-A and other trials that have used electronic brachytherapy. More modern approaches, in which the lumpectomy procedure is integrated into an APBI workflow, will also be discussed. Learning Objectives: To review past and current clinical trials for IORT To discuss lumpectomy-scan-plan-treat workflow for IORT.« less

Dosimetric audit in brachytherapy

PubMed Central

Bradley, D A; Nisbet, A

2014-01-01

Dosimetric audit is required for the improvement of patient safety in radiotherapy and to aid optimization of treatment. The reassurance that treatment is being delivered in line with accepted standards, that delivered doses are as prescribed and that quality improvement is enabled is as essential for brachytherapy as it is for the more commonly audited external beam radiotherapy. Dose measurement in brachytherapy is challenging owing to steep dose gradients and small scales, especially in the context of an audit. Several different approaches have been taken for audit measurement to date: thimble and well-type ionization chambers, thermoluminescent detectors, optically stimulated luminescence detectors, radiochromic film and alanine. In this work, we review all of the dosimetric brachytherapy audits that have been conducted in recent years, look at current audits in progress and propose required directions for brachytherapy dosimetric audit in the future. The concern over accurate source strength measurement may be essentially resolved with modern equipment and calibration methods, but brachytherapy is a rapidly developing field and dosimetric audit must keep pace. PMID:24807068

MRI-guided brachytherapy

PubMed Central

Tanderup, Kari; Viswanathan, Akila; Kirisits, Christian; Frank, Steven J.

2014-01-01

The application of MRI-guided brachytherapy has demonstrated significant growth during the last two decades. Clinical improvements in cervix cancer outcomes have been linked to the application of repeated MRI for identification of residual tumor volumes during radiotherapy. This has changed clinical practice in the direction of individualized dose administration, and mounting evidence of improved clinical outcome with regard to local control, overall survival as well as morbidity. MRI-guided prostate HDR and LDR brachytherapy has improved the accuracy of target and organs-at-risk (OAR) delineation, and the potential exists for improved dose prescription and reporting for the prostate gland and organs at risk. Furthermore, MRI-guided prostate brachytherapy has significant potential to identify prostate subvolumes and dominant lesions to allow for dose administration reflecting the differential risk of recurrence. MRI-guided brachytherapy involves advanced imaging, target concepts, and dose planning. The key issue for safe dissemination and implementation of high quality MRI-guided brachytherapy is establishment of qualified multidisciplinary teams and strategies for training and education. PMID:24931089

American Society for Radiation Oncology (ASTRO) and American College of Radiology (ACR) Practice Guideline for the Performance of High-Dose-Rate Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erickson, Beth A.; Demanes, D. Jeffrey; Ibbott, Geoffrey S.

2011-03-01

High-Dose-Rate (HDR) brachytherapy is a safe and efficacious treatment option for patients with a variety of different malignancies. Careful adherence to established standards has been shown to improve the likelihood of procedural success and reduce the incidence of treatment-related morbidity. A collaborative effort of the American College of Radiology (ACR) and American Society for Therapeutic Radiation Oncology (ASTRO) has produced a practice guideline for HDR brachytherapy. The guideline defines the qualifications and responsibilities of all the involved personnel, including the radiation oncologist, physicist and dosimetrists. Review of the leading indications for HDR brachytherapy in the management of gynecologic, thoracic, gastrointestinal,more » breast, urologic, head and neck, and soft tissue tumors is presented. Logistics with respect to the brachytherapy implant procedures and attention to radiation safety procedures and documentation are presented. Adherence to these practice guidelines can be part of ensuring quality and safety in a successful HDR brachytherapy program.« less

Patterns of brachytherapy practice for patients with carcinoma of the cervix (1996-1999): a patterns of care study.

PubMed

Erickson, Beth; Eifel, Patricia; Moughan, Jennifer; Rownd, Jason; Iarocci, Thomas; Owen, Jean

2005-11-15

To analyze the details of brachytherapy practice in patients treated for carcinoma of the cervix in the United States between 1996 and 1999. Radiation facilities were selected from a stratified random sample. Patients were randomly selected from lists of eligible patients treated at each facility. A total of 442 patients' records were reviewed in 59 facilities to obtain data about patients' characteristics, evaluation, tumor extent, and treatment. National estimates were made using weights that reflected the relative contribution of each institution and of each patient within the sampled institutions. From our survey we estimate that 16,375 patients were treated in the United States during this study period. Unless otherwise specified, brachytherapy practice was based on the 408 patients who had their brachytherapy or all their treatment at the surveyed facility. A total of 91.5% of patients underwent brachytherapy at the initial treating institution; 8.5% were referred to a second site for brachytherapy. Forty-two percent of U.S. facilities referred at least some patients to a second facility for brachytherapy. Of U.S. facilities that treated < or =2 eligible patients per year, 61% referred all of their patients to a second facility for brachytherapy or treated with external RT alone; none of the U.S. facilities with larger experience (>2 eligible patients per year) referred all their patients to a second facility for brachytherapy treatment, but 28% referred some patients to an outside facility for brachytherapy. Overall, 94% of patients who completed treatment with curative intent received brachytherapy. Of these patients who had brachytherapy, 77.8%, 13.3%, and 0.9%, respectively, were treated with low-dose-rate (LDR), high-dose-rate (HDR), or a combination of HDR and LDR brachytherapy; 7.9% had interstitial brachytherapy (5.7% LDR and 1.9% HDR, 0.3% mixed). In facilities that treated >2 patients per year, 15.5% and 9.4% of brachytherapy procedures included HDR or interstitial, respectively; in facilities that treated fewer patients, 3.4% had HDR brachytherapy, and only 1.2% had interstitial brachytherapy. Patients treated with LDR intracavitary radiotherapy had one (23.5%), two (74.1%), or three (2.4%) implants. For patients treated with curative intent who completed radiation therapy with LDR intracavitary radiation therapy without hysterectomy, the median brachytherapy dose to Point A was 40.3 Gy, and the median total dose to Point A was 82.9 Gy. Patients were treated with HDR intracavitary radiation therapy using a variety of treatment schedules using 1-2 fractions (7.5%), 3-4 fractions (17.4%), 5-6 fractions (38.5%), 7-9 fractions (33.5%), or 12 fractions (3%). Fraction sizes were <500 cGy (29.5%), 500-<600 (25.2%), 600 (28.1%), >600 (8%), or unknown (9.2%). For patients treated with HDR, the median total dose to Point A (corrected for fraction size using a alpha/beta = 10) was 85.8 Gy (range: 56.2-116.1 Gy). At institutions treating <500 new patients per year, the percentage of patients receiving a brachytherapy dose <40 Gy was significantly higher than at institutions treating > or =500 new patients per year (p < 0.0001). For LDR intracavitary radiation therapy, 5.8% had neither bladder nor rectal doses recorded for any of their implants, whereas in HDR intracavitary radiation therapy, 73.4% had neither bladder nor rectal doses recorded for any of their implants. The median total duration of radiation therapy was identical for patients who had HDR or LDR intracavitary radiation therapy (57 days). For LDR at institutions treating <500 new patients per year, the percentage of patients with treatment duration >56 days was significantly greater than at institutions > or =500 new patients per year (p = 0.002). Of the patients who had LDR intracavitary radiation therapy implants, 65% were treated using tandem and shielded Fletcher-Suit-Delclos colpostats; other patients had mini ovoids (10.9%), cylinders (3.9%), Henschke (3.7%), or other/mixed applicators (16.5%). In contrast, of patients treated with HDR intracavitary radiation therapy, 68.7% had tandem and rings, 18.2% Fletcher-Suit-Delclos ovoids, 7.5% mini ovoids, 2.3% cylinders, and 3.2% other or mixed applicators. The median duration of treatment and median Point A dose were very similar for patients treated with HDR or LDR. Patients with HDR were treated using a variety of treatment schedules. Different applicator types were favored for LDR vs. HDR. Of patients treated with HDR, 73.4% had no brachytherapy bladder or rectal doses recorded, suggesting that full dosimetric calculations were performed only for the first fraction in many institutions. Facility size significantly impacted on referral to another institution for brachytherapy, brachytherapy dose, and treatment duration.

Place of modern imaging in brachytherapy planning.

PubMed

Hellebust, T P

2018-06-01

Imaging has probably been the most important driving force for the development of brachytherapy treatments the last 20 years. Due to implementation of three-dimensional imaging, brachytherapy is nowadays a highly accurate and reliable treatment option for many cancer patients. To be able to optimize the dose distribution in brachytherapy the anatomy and the applicator(s) or sources should be correctly localised in the images. For computed tomography (CT) the later criteria is easily fulfilled for most brachytherapy sites. However, for many sites, like cervix and prostate, CT is not optimal for delineation since soft tissue is not adequately visualized and the tumor is not well discriminated. For cervical cancer treatment planning based on magnetic resonance imaging (MRI) is recommended. Some centres also use MRI for postimplant dosimetry of permanent prostate seed implant and high dose rate prostate brachytherapy. Moreover, in so called focal brachytherapy where only a part of the prostate is treated, multiparametric MRI is an excellent tool that can assist in defining the target volume. Applicator or source localization is challenging using MRI, but tolls exist to assist this process. Also, geometrical distortions should be corrected or accounted for. Transrectal ultrasound is considered to be the gold standard for high dose rate prostate brachytherapy and transrectal ultrasound -based brachytherapy procedure offers a method for interactive treatment planning. Reconstruction of the needles is sometimes challenging, especially to identify the needle tip. The accuracy of the reconstruction could be improved by measuring the residuals needle length and by using a bi-planar transducer. The last decade several groups worldwide have explored the use of transrectal and transabdominal ultrasound for cervical cancer brachytherapy. Since ultrasonography is widely available, offers fast image acquisition and is a rather inexpensive modality such development is interesting. However, more work is needed to establish this as an adequate alternative for all phases of the treatment planning process. Studies using positron emission tomography imaging in combination with brachytherapy treatment planning are limited. However, development of new tracers may offer new treatment approaches for brachytherapy in the future. Combination of several image modalities will be the optimal solution in many situations, either during the same session or for different fractions. When several image modalities are combined so called image registration procedures are used and it is important to understand the principles and limitations of such procedures. Copyright © 2018 Société française de radiothérapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.

78 FR 41125 - Interim Enforcement Policy for Permanent Implant Brachytherapy Medical Event Reporting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-09

... Brachytherapy Medical Event Reporting AGENCY: Nuclear Regulatory Commission. ACTION: Policy statement; revision... medical events occurring under an NRC licensee's permanent implant brachytherapy program. This interim..., ``Adequacy of Medical Event Definitions in 10 CFR [Title 10 of the Code of Federal Regulations] 35.3045, and...

Alpha 1-Adrenoceptor Blocker May Improve Not Only Voiding But Also Storage Lower Urinary Tract Symptoms Caused by 125I Brachytherapy for Prostate Cancer

PubMed Central

Aoki, Yoshitaka; Ito, Hideaki; Miwa, Yoshiji; Akino, Hironobu; Shioura, Hiroki; Kimura, Hirohiko; Yokoyama, Osamu

2014-01-01

Purpose. To assess changes in lower urinary tract symptoms (LUTS) within 1 year after brachytherapy in patients receiving alpha 1-adrenoceptor antagonists. Methods. We retrospectively evaluated 116 patients who underwent 125I prostate brachytherapy in our institute. Seventy-one patients were treated with a combination of external beam radiation therapy and brachytherapy. Alpha 1-adrenoceptor antagonists were prescribed to all patients after brachytherapy. International Prostate Symptom Score (IPSS) forms and postvoid residual urine volume were recorded at all follow-up visits. Results. Forty-nine patients were given tamsulosin hydrochloride, 32 were given silodosin hydrochloride, and 35 were given naftopidil for up to 6 months after seed implantation. Patients given tamsulosin or naftopidil tended to show a higher peak IPSS and slower recovery to baseline values than those given silodosin. The patients given naftopidil showed an insufficient recovery in storage symptoms in naftopidil group in comparison with tamsulosin group at 3 months and with silodosin group at 6 and 9 months. Conclusions. In the management of LUT after brachytherapy, silodosin may provide a more favorable improvement. Silodosin and tamsulosin may have an advantage in improving not only voiding but also storage lower urinary tract symptoms after brachytherapy. PMID:25006516

Low-Dose-Rate Brachytherapy Versus Cryotherapy in Low- and Intermediate-Risk Prostate Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gestaut, Matthew M., E-mail: Matthew.Gestaut@BSWHealth.org; Cai, Wendi; Vyas, Shilpa

Purpose: Cryotherapy and brachytherapy are definitive local treatment options for low- to intermediate-risk prostate cancer. There are both prospective and retrospective data for brachytherapy, but the use of cryotherapy has been limited primarily to single-institution retrospective studies. Currently, no published evidence has compared low-dose-rate brachytherapy versus cryotherapy. Methods and Materials: Institutional review board approval was obtained to conduct a retrospective chart review of consecutive patients treated at our institution from 1990 to 2012. For inclusion, patients must have received a prostate cancer diagnosis and have been considered to have low- to intermediate-risk disease according to the National Comprehensive Cancer Networkmore » criteria. All patients received brachytherapy or cryotherapy treatment. Disease specifics and failure details were collected for all patients. Failure was defined as prostate-specific antigen nadir +2 ng/mL. Results: A total of 359 patients were analyzed. The groups comprised 50 low-risk cryotherapy (LRC), 92 intermediate-risk cryotherapy (IRC), 133 low-risk brachytherapy (LRB), and 84 intermediate-risk brachytherapy (IRB) patients. The median prostate-specific antigen follow-up periods were 85.6 months (LRC), 59.2 months (IRC), 74.9 months (LRB), and 59.8 months (IRB). The 5-year biochemical progression–free survival (bPFS) rate was 57.9% in the cryotherapy group versus 89.6% in the brachytherapy group (P<.0001). The 5-year bPFS rate was 70.0% (LRC), 51.4% (IRC), 89.4% (LRB), and 89.7% (IRB). The bPFS rate was significantly different between brachytherapy and cryotherapy for low- and intermediate-risk groups (P<.05). The mean nadir temperature reached for cryotherapy patients was −35°C (range, −96°C to −6°C). Cryotherapy used a median of 2 freeze-thaw cycles (range, 2-4 freeze-thaw cycles). Conclusions: Results from this study suggest that cryotherapy is inferior to brachytherapy for patients with low- to intermediate-risk prostate cancer. Patient selection criteria for consideration of cryotherapy and brachytherapy are similar in terms of anesthesia candidacy. Therefore, cryotherapy would not be recommended as a first-line local therapy for this particular patient subset.« less

Failure modes and effects analysis for ocular brachytherapy.

PubMed

Lee, Yongsook C; Kim, Yongbok; Huynh, Jason Wei-Yeong; Hamilton, Russell J

The aim of the study was to identify potential failure modes (FMs) having a high risk and to improve our current quality management (QM) program in Collaborative Ocular Melanoma Study (COMS) ocular brachytherapy by undertaking a failure modes and effects analysis (FMEA) and a fault tree analysis (FTA). Process mapping and FMEA were performed for COMS ocular brachytherapy. For all FMs identified in FMEA, risk priority numbers (RPNs) were determined by assigning and multiplying occurrence, severity, and lack of detectability values, each ranging from 1 to 10. FTA was performed for the major process that had the highest ranked FM. Twelve major processes, 121 sub-process steps, 188 potential FMs, and 209 possible causes were identified. For 188 FMs, RPN scores ranged from 1.0 to 236.1. The plaque assembly process had the highest ranked FM. The majority of FMs were attributable to human failure (85.6%), and medical physicist-related failures were the most numerous (58.9% of all causes). After FMEA, additional QM methods were included for the top 10 FMs and 6 FMs with severity values > 9.0. As a result, for these 16 FMs and the 5 major processes involved, quality control steps were increased from 8 (50%) to 15 (93.8%), and major processes having quality assurance steps were increased from 2 to 4. To reduce high risk in current clinical practice, we proposed QM methods. They mainly include a check or verification of procedures/steps and the use of checklists for both ophthalmology and radiation oncology staff, and intraoperative ultrasound-guided plaque positioning for ophthalmology staff. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

WE-G-BRA-04: Common Errors and Deficiencies in Radiation Oncology Practice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kry, S; Dromgoole, L; Alvarez, P

Purpose: Dosimetric errors in radiotherapy dose delivery lead to suboptimal treatments and outcomes. This work reviews the frequency and severity of dosimetric and programmatic errors identified by on-site audits performed by the IROC Houston QA center. Methods: IROC Houston on-site audits evaluate absolute beam calibration, relative dosimetry data compared to the treatment planning system data, and processes such as machine QA. Audits conducted from 2000-present were abstracted for recommendations, including type of recommendation and magnitude of error when applicable. Dosimetric recommendations corresponded to absolute dose errors >3% and relative dosimetry errors >2%. On-site audits of 1020 accelerators at 409 institutionsmore » were reviewed. Results: A total of 1280 recommendations were made (average 3.1/institution). The most common recommendation was for inadequate QA procedures per TG-40 and/or TG-142 (82% of institutions) with the most commonly noted deficiency being x-ray and electron off-axis constancy versus gantry angle. Dosimetrically, the most common errors in relative dosimetry were in small-field output factors (59% of institutions), wedge factors (33% of institutions), off-axis factors (21% of institutions), and photon PDD (18% of institutions). Errors in calibration were also problematic: 20% of institutions had an error in electron beam calibration, 8% had an error in photon beam calibration, and 7% had an error in brachytherapy source calibration. Almost all types of data reviewed included errors up to 7% although 20 institutions had errors in excess of 10%, and 5 had errors in excess of 20%. The frequency of electron calibration errors decreased significantly with time, but all other errors show non-significant changes. Conclusion: There are many common and often serious errors made during the establishment and maintenance of a radiotherapy program that can be identified through independent peer review. Physicists should be cautious, particularly in areas highlighted herein that show a tendency for errors.« less

Characterization of Low-Energy Photon-Emitting Brachytherapy Sources with Modified Strengths for Applications in Focal Therapy

NASA Astrophysics Data System (ADS)

Reed, Joshua L.

Permanent implants of low-energy photon-emitting brachytherapy sources are used to treat a variety of cancers. Individual source models must be separately characterized due to their unique geometry, materials, and radionuclides, which all influence their dose distributions. Thermoluminescent dosimeters (TLDs) are often used for dose measurements around low-energy photon-emitting brachytherapy sources. TLDs are typically calibrated with higher energy sources such as 60Co, which requires a correction for the change in the response of the TLDs as a function of photon energy. These corrections have historically been based on TLD response to x ray bremsstrahlung spectra instead of to brachytherapy sources themselves. This work determined the TLD intrinsic energy dependence for 125I and 103Pd sources relative to 60Co, which allows for correction of TLD measurements of brachytherapy sources with factors specific to their energy spectra. Traditional brachytherapy sources contain mobile internal components and large amounts of high-Z material such as radio-opaque markers and titanium encapsulations. These all contribute to perturbations and uncertainties in the dose distribution around the source. The CivaString is a new elongated 103Pd brachytherapy source with a fixed internal geometry, polymer encapsulation, and lengths ranging from 1 to 6 cm, which offers advantages over traditional source designs. This work characterized the CivaString source and the results facilitated the formal approval of this source for use in clinical treatments. Additionally, the accuracy of a superposition technique for dose calculation around the sources with lengths >1 cm was verified. Advances in diagnostic techniques are paving the way for focal brachytherapy in which the dose is intentionally modulated throughout the target volume to focus on subvolumes that contain cancer cells. Brachytherapy sources with variable longitudinal strength (VLS) are a promising candidate for use in focal brachytherapy treatments given their customizable activity distributions, although they are not yet commercially available. This work characterized five prototype VLS sources, developed methods for clinical calibration and verification of these sources, and developed an analytical dose calculation algorithm that scales with both source length and VLS.

Single dose irradiation response of pig skin: a comparison of brachytherapy using a single, high dose rate iridium-192 stepping source with 200 kV X-rays.

PubMed

Hamm, P C; Bakker, E J; van den Berg, A P; van den Aardweg, G J; Visser, A G; Levendag, P C

2000-07-01

An experimental brachytherapy model has been developed to study acute and late normal tissue reactions as a tool to examine the effects of clinically relevant multifractionation schedules. Pig skin was used as a model since its morphology, structure, cell kinetics and radiation-induced responses are similar to human skin. Brachytherapy was performed using a microSelectron high dose rate (HDR) afterloading machine with a single stepping source and a custom-made template. In this study the acute epidermal reactions of erythema and moist desquamation and the late dermal reactions of dusky mauve erythema and necrosis were evaluated after single doses of irradiation over a follow-up period of 16 weeks. The major aims of this work were: (a) to compare the effects of iridium-192 (192Ir) irradiation with effects after X-irradiation; (b) to compare the skin reactions in Yorkshire and Large White pigs; and (c) to standardize the methodology. For 192Ir irradiation with 100% isodose at the skin surface, the 95% isodose was estimated at the basal membrane, while the 80% isodose covered the dermal fat layers. After HDR 192Ir irradiation of Yorkshire pig skin the ED50 values (95% isodose) for moderate/severe erythema and moist desquamation were 24.8 Gy and 31.9 Gy, respectively. The associated mean latent period (+/- SD) was 39 +/- 7 days for both skin reactions. Late skin responses of dusky mauve erythema and dermal necrosis were characterized by ED50 values (80% isodose) of 16.3 Gy and 19.5 Gy, with latent periods of 58 +/- 7 days and 76 +/- 12 days, respectively. After X-irradiation, the incidence of the various skin reactions and their latent periods were similar. Acute and late reactions were well separated in time. The occurrence of skin reactions and the incidence of effects were comparable in Yorkshire and Large White pigs for both X-irradiation and HDR 192Ir brachytherapy. This pig skin model is feasible for future studies on clinically relevant multifractionation schedules in a brachytherapy setting.

Cervical brachytherapy technique for locally advanced carcinoma of the cervix in a patient with septate uterus.

PubMed

Platta, Christopher S; Wallace, Charlie; Gondi, Vinai; Das, Rupak; Straub, Margaret; Al-Niaimi, Ahmed; Applegate, Glenn; Bradley, Kristin A

2014-03-01

To describe an approach to cervical brachytherapy in a patient with congenital septate uterus and locally advanced cervical carcinoma. The patient is a 34-year-old female with septate uterus presenting with pelvic pain. Workup demonstrated a stage IIB cervical adenocarcinoma with imaging evidence of an involved right external iliac lymph node. The patient received whole pelvic radiation, with concurrent weekly cisplatin (40 mg/m(2)), to a dose of 45 Gy in 25 fractions followed by a parametrial boost of 5.4 Gy and an additional nodal boost of 9 Gy. The patient was initiated on cervical brachytherapy following fraction 23 of pelvic radiation. To conform to her septated uterus, a Rotte-Y tandem was used. Additionally, 2 CT-compatible ovoids were placed in the vaginal apex to enhance dose distribution and coverage of the target volume. Each fraction of brachytherapy was performed with CT-based planning. A high-risk clinical target volume (HR-CTV) and normal structures were defined and constrained per American Brachytherapy Society (ABS) and Groupe Européen de Curiethérapie/European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) guidelines. The brachytherapy dose was 27.5 Gy in 5 fractions of 5.5 Gy each, prescribed to the HR-CTV. Herein, we report the first documented case of cervical brachytherapy in a patient with septate uterus and locally advanced cervical carcinoma. Using CT-guided planning, in conjunction with the ABS and GEC-ESTRO guidelines, the patient was effectively treated with adapted cervical brachytherapy, meeting criteria for HR-CTV coverage and normal tissue tolerances.

Interventional Radiation Oncology (IRO): Transition of a magnetic resonance simulator to a brachytherapy suite.

PubMed

Anderson, Roberta; Armour, Elwood; Beeckler, Courtney; Briner, Valerie; Choflet, Amanda; Cox, Andrea; Fader, Amanda N; Hannah, Marie N; Hobbs, Robert; Huang, Ellen; Kiely, Marilyn; Lee, Junghoon; Morcos, Marc; McMillan, Paige E; Miller, Dave; Ng, Sook Kien; Prasad, Rashmi; Souranis, Annette; Thomsen, Robert; DeWeese, Theodore L; Viswanathan, Akila N

As a core component of a new gynecologic cancer radiation program, we envisioned, structured, and implemented a novel Interventional Radiation Oncology (IRO) unit and magnetic resonance (MR)-brachytherapy environment in an existing MR simulator. We describe the external and internal processes required over a 6-8 month time frame to develop a clinical and research program for gynecologic brachytherapy and to successfully convert an MR simulator into an IRO unit. Support of the institution and department resulted in conversion of an MR simulator to a procedural suite. Development of the MR gynecologic brachytherapy program required novel equipment, staffing, infrastructural development, and cooperative team development with anesthetists, nurses, therapists, physicists, and physicians to ensure a safe and functional environment. Creation of a separate IRO unit permitted a novel billing structure. The creation of an MR-brachytherapy environment in an MR simulator is feasible. Developing infrastructure includes several collaborative elements. Unique to the field of radiation oncology, formalizing the space as an Interventional Radiation Oncology unit permits a sustainable financial structure. Copyright © 2018 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Treating Locally Advanced Cervical Cancer With Concurrent Chemoradiation Without Brachytherapy in Low-resource Countries.

PubMed

Chuang, Linus; Kanis, Margaux J; Miller, Brigitte; Wright, Jason; Small, William; Creasman, William

2016-02-01

To summarize the literature on options of management of patients treated for locally advanced cervical cancers with a specific focus on resource-constrained settings where brachytherapy is not available. A Medline search was performed to summarize studies about treatment approaches including neoadjuvant chemotherapy, primary surgery for bulky cervical cancer, and chemoradiation followed by surgery. Summaries are by treatment approaches that are relevant to resource-constrained settings. There are a lack of studies performed on neoadjuvant chemotherapy in low-resource settings. Primary surgery followed by chemoradiation therapy for selected patients with bulky cervical cancer is a feasible option. The disadvantage is the potential increase in treatment complications. Chemoradiation without brachytherapy followed by surgery has been found to have equivalent outcomes and is associated with acceptable morbidity. In resource-constrained settings where brachytherapy is not available, performing radical hysterectomy after chemoradiation therapy without brachytherapy has been shown to produce equivalent outcomes. It seems reasonable to adopt a modified therapeutic protocol of chemoradiation followed by extrafascial hysterectomy as an alternative treatment option in low-resource countries where brachytherapy is not readily available.

Brachytherapy for Prostate Cancer: A Systematic Review

PubMed Central

Koukourakis, Georgios; Kelekis, Nikolaos; Armonis, Vassilios; Kouloulias, Vassilios

2009-01-01

Low-dose rate brachytherapy has become a mainstream treatment option for men diagnosed with prostate cancer because of excellent long-term treatment outcomes in low-, intermediate-, and high-risk patients. To a great extend due to patient lead advocacy for minimally invasive treatment options, high-quality prostate implants have become widely available in the US, Europe, and Japan. High-dose-rate (HDR) afterloading brachytherapy in the management of localised prostate cancer has practical, physical, and biological advantages over low-dose-rate seed brachytherapy. There are no free live sources used, no risk of source loss, and since the implant is a temporary procedure following discharge no issues with regard to radioprotection use of existing facilities exist. Patients with localized prostate cancer may benefit from high-dose-rate brachytherapy, which may be used alone in certain circumstances or in combination with external-beam radiotherapy in other settings. The purpose of this paper is to present the essentials of brachytherapies techniques along with the most important studies that support their effectiveness in the treatment of prostate cancer. PMID:19730753

Percutaneous interstitial brachytherapy for adrenal metastasis: technical report.

PubMed

Kishi, Kazushi; Tamura, Shinji; Mabuchi, Yasushi; Sonomura, Tetsuo; Noda, Yasutaka; Nakai, Motoki; Sato, Morio; Ino, Kazuhiko; Yamanaka, Noboru

2012-09-01

We developed and evaluated the feasibility of a brachytherapy technique as a safe and effective treatment for adrenal metastasis. Adapting a paravertebral insertion technique in radiofrequency ablation of adrenal tumors, we developed an interstitial brachytherapy for adrenal metastasis achievable on an outpatient basis. Under local anesthesia and under X-ray CT guidance, brachytherapy applicator needles were percutaneously inserted into the target. A treatment plan was created to eradicate the tumor while preserving normal organs including the spinal cord and kidney. We applied this interstitial brachytherapy technique to two patients: one who developed adrenal metastasis as the third recurrence of uterine cervical cancer after reirradiation, and one who developed metachronous multiple metastases from malignant melanoma. The whole procedure was completed in 2.5 hours. There were no procedure-related or radiation-related early/late complications. FDG PET-CT images at two and three months after treatment showed absence of FDG uptake, and no recurrence of the adrenal tumor was observed for over seven months until expiration, and for six months until the present, respectively. This interventional interstitial brachytherapy procedure may be useful as a safe and eradicative treatment for adrenal metastasis.

External beam techniques to boost cervical cancer when brachytherapy is not an option—theories and applications

PubMed Central

Kilic, Sarah; Khan, Atif J.; Beriwal, Sushil; Small, William

2017-01-01

The management of locally advanced cervical cancer relies on brachytherapy (BT) as an integral part of the radiotherapy delivery armamentarium. Occasionally, intracavitary BT is neither possible nor available. In these circumstances, post-external beam radiotherapy (EBRT) interstitial brachytherapy and/or hysterectomy may represent viable options that must be adequately executed in a timely manner. However, if these options are not applicable due to patient related or facility related reasons, a formal contingency plan should be in place. Innovative EBRT techniques such as intensity modulated and stereotactic radiotherapy may be considered for patients unable to undergo brachytherapy. Relying on provocative arguments and recent data, this review explores the rationale for and limitations of non-brachytherapy substitutes in that setting aiming to establish a formal process for the optimal execution of this alternative plan. PMID:28603722

Dosimetric characteristics of a new unit for electronic skin brachytherapy

PubMed Central

Garcia-Martinez, Teresa; Chan, Jan-Pieter; Perez-Calatayud, Jose

2014-01-01

Purpose Brachytherapy with radioactive high dose rate (HDR) 192Ir source is applied to small skin cancer lesions, using surface applicators, i.e. Leipzig or Valencia type. New developments in the field of radiotherapy for skin cancer include electronic brachytherapy. This technique involves the placement of an HDR X-ray source close to the skin, therefore combining the benefits of brachytherapy with the reduced shielding requirements and targeted energy of low energy X-rays. Recently, the Esteya® Electronic Brachytherapy System (Esteya EBS, Elekta AB-Nucletron, Stockholm, Sweden) has been developed specifically for HDR brachytherapy treatment of surface lesions. The system provides radionuclide free HDR brachytherapy by means of a small 69.5 kV X-ray source. The purpose of this study is to obtain the dosimetric characterization required for clinical implementation, providing the detailed methodology to perform the commissioning. Material and methods Flatness, symmetry and penumbra, percentage of depth dose (PDD), kV stability, HVL, output, spectrum, linearity, and leakage have been evaluated for a set of applicators (from 10 mm to 30 mm in diameter). Results Flatness and symmetry resulted better than 5% with around 1 mm of penumbra. The depth dose gradient is about 7%/mm. A kV value of 68.4 ± 1.0 kV (k = 1) was obtained, in good agreement with manufacturer data (69.5 kV). HVL was 1.85 mm Al. Dose rate for a typical 6 Gy to 7 Gy prescription resulted about 3.3 Gy/min and the leakage value was < 100 µGy/min. Conclusions The new Esteya® Electronic Brachytherapy System presents excellent flatness and penumbra as with the Valencia applicator case, combined with an improved PDD, allowing treatment of lesions of up to a depth of 5 mm in combination with reduced treatment duration. The Esteya unit allows HDR brachytherapy superficial treatment within a minimally shielded environment due its low energy. PMID:24790622

Definition of medical event is to be based on the total source strength for evaluation of permanent prostate brachytherapy: A report from the American Society for Radiation Oncology.

PubMed

Nag, Subir; Demanes, D Jeffrey; Hagan, Michael; Rivard, Mark J; Thomadsen, Bruce R; Welsh, James S; Williamson, Jeffrey F

2011-10-01

The Nuclear Regulatory Commission deems it to be a medical event (ME) if the total dose delivered differs from the prescribed dose by 20% or more. A dose-based definition of ME is not appropriate for permanent prostate brachytherapy as it generates too many spurious MEs and thereby creates unnecessary apprehension in patients, and ties up regulatory bodies and the licensees in unnecessary and burdensome investigations. A more suitable definition of ME is required for permanent prostate brachytherapy. The American Society for Radiation Oncology (ASTRO) formed a working group of experienced clinicians to review the literature, assess the validity of current regulations, and make specific recommendations about the definition of an ME in permanent prostate brachytherapy. The working group found that the current definition of ME in §35.3045 as "the total dose delivered differs from the prescribed dose by 20 percent or more" was not suitable for permanent prostate brachytherapy since the prostate volume (and hence the resultant calculated prostate dose) is dependent on the timing of the imaging, the imaging modality used, the observer variability in prostate contouring, the planning margins used, inadequacies of brachytherapy treatment planning systems to calculate tissue doses, and seed migration within and outside the prostate. If a dose-based definition for permanent implants is applied strictly, many properly executed implants would be improperly classified as an ME leading to a detrimental effect on brachytherapy. The working group found that a source strength-based criterion, of >20% of source strength prescribed in the post-procedure written directive being implanted outside the planning target volume is more appropriate for defining ME in permanent prostate brachytherapy. ASTRO recommends that the definition of ME for permanent prostate brachytherapy should not be dose based but should be based upon the source strength (air-kerma strength) administered.

The American brachytherapy society survey of brachytherapy practice for carcinoma of the cervix in the United States.

PubMed

Nag, S; Orton, C; Young, D; Erickson, B

1999-04-01

The purpose of this study was to survey the brachytherapy practice for cervical cancer in the United States. The Clinical Research Committee of the American Brachytherapy Society (ABS) performed a retrospective survey of individual physicians of the ABS and American Society of Therapeutic Radiologists and Oncologists regarding the details of the brachytherapy techniques they personally used in the treatment of cervical cancer patients for the year 1995. The replies (some of which may have been an estimate only) were tabulated. The scope of this survey did not allow us to verify the data by chart audits. A total of about 3500 questionnaires were mailed out; 521 responses were received. Of these responders, 206 (40%) did not perform any brachytherapy for carcinoma of the cervix in 1995. Of the other 315 responders reporting a total of 4892 patients treated in 1995, 88% used low dose rate (LDR) while 24% used high dose rate (HDR). There was a wide variation in the doses used. For LDR treatments, the median total external beam radiation therapy (EBRT) dose was 45 and 50 Gy and the LDR dose was 42 and 45 Gy for early and advanced cancers, respectively. For HDR treatments, the median EBRT dose was 48 and 50 Gy and the median HDR dose was 29 and 30 Gy for early and advanced cancers, respectively. The median dose per fraction was 6 Gy for a median of five fractions. Interstitial brachytherapy was used as a component of the treatment in 6% of the patients by 21% of responders. Very few responders treated with pulsed or medium dose rates. This retrospective survey showed the current brachytherapy practice pattern in the treatment of cervical cancer in the United States and can serve as a basis for future prospective national brachytherapy data registry. There was wide variation in the practice pattern, emphasizing the urgent need for consensus on these issues. Copyright 1999 Academic Press.

Brachytherapy for cervix cancer: low-dose rate or high-dose rate brachytherapy – a meta-analysis of clinical trials

PubMed Central

Viani, Gustavo A; Manta, Gustavo B; Stefano, Eduardo J; de Fendi, Ligia I

2009-01-01

Background The literature supporting high-dose rate brachytherapy (HDR) in the treatment of cervical carcinoma derives primarily from retrospective series. However, controversy still persists regarding the efficacy and safety of HDR brachytherapy compared to low-dose rate (LDR) brachytherapy, in particular, due to inadequate tumor coverage for stage III patients. Whether LDR or HDR brachytherapy produces better results for these patients in terms of survival rate, local control rate and the treatment complications remain controversial. Methods A meta-analysis of RCT was performed comparing LDR to HDR brachytherapy for cervix cancer treated for radiotherapy alone. The MEDLINE, EMBASE, CANCERLIT and Cochrane Library databases, as well as abstracts published in the annual proceedings were systematically searched. We assessed methodological quality for each outcome by grading the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. We used "recommend" for strong recommendations, and "suggest" for weak recommendations. Results Pooled results from five randomized trials (2,065 patients) of HDR brachytherapy in cervix cancer showed no significant increase of mortality (p = 0.52), local recurrence (p = 0.68), or late complications (rectal; p = 0.7, bladder; p = 0.95 or small intestine; p = 0.06) rates as compared to LDR brachytherapy. In the subgroup analysis no difference was observed for overall mortality and local recurrence in patients with clinical stages I, II and III. The quality of evidence was low for mortality and local recurrence in patients with clinical stage I, and moderate for other clinical stages. Conclusion Our meta-analysis shows that there are no differences between HDR and LDR for overall survival, local recurrence and late complications for clinical stages I, II and III. By means of the GRADE system, we recommend the use of HDR for all clinical stages of cervix cancer. PMID:19344527

[Why is brachytherapy still essential in 2017?

PubMed

Haie-Méder, C; Maroun, P; Fumagalli, I; Lazarescu, I; Dumas, I; Martinetti, F; Chargari, C

2018-05-16

These recent years, brachytherapy has benefited from imaging modalities advances. A more systematic use of tomodensitometric, ultrasonographic and MRI images during brachytherapy procedures has allowed an improvement in target and organs at risk assessment as well as their relationship with the applicators. New concepts integrating tumor regression during treatment have been defined and have been clinically validated. New applicators have been developed and are commercially available. Optimization processes have been developed, integrating hypofractionation modalities leading to tumor control improvement. All these opportunities led to further development of brachytherapy, with indisputable ballistic advantages, especially compared to external irradiation. Copyright © 2018. Published by Elsevier SAS.

Design and testing of a phantom and instrumented gynecological applicator based on GaN dosimeter for use in high dose rate brachytherapy quality assurance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guiral, P.; Ribouton, J.; Jalade, P.

Purpose: High dose rate brachytherapy (HDR-BT) is widely used to treat gynecologic, anal, prostate, head, neck, and breast cancers. These treatments are typically administered in large dose per fraction (>5 Gy) and with high-gradient-dose-distributions, with serious consequences in case of a treatment delivery error (e.g., on dwell position and dwell time). Thus, quality assurance (QA) or quality control (QC) should be systematically and independently implemented. This paper describes the design and testing of a phantom and an instrumented gynecological applicator for pretreatment QA and in vivo QC, respectively. Methods: The authors have designed a HDR-BT phantom equipped with four GaN-basedmore » dosimeters. The authors have also instrumented a commercial multichannel HDR-BT gynecological applicator by rigid incorporation of four GaN-based dosimeters in four channels. Specific methods based on the four GaN dosimeter responses are proposed for accurate determination of dwell time and dwell position inside phantom or applicator. The phantom and the applicator have been tested for HDR-BT QA in routine over two different periods: 29 and 15 days, respectively. Measurements in dwell position and time are compared to the treatment plan. A modified position–time gamma index is used to monitor the quality of treatment delivery. Results: The HDR-BT phantom and the instrumented applicator have been used to determine more than 900 dwell positions over the different testing periods. The errors between the planned and measured dwell positions are 0.11 ± 0.70 mm (1σ) and 0.01 ± 0.42 mm (1σ), with the phantom and the applicator, respectively. The dwell time errors for these positions do not exhibit significant bias, with a standard deviation of less than 100 ms for both systems. The modified position–time gamma index sets a threshold, determining whether the treatment run passes or fails. The error detectability of their systems has been evaluated through tests on intentionally introduced error protocols. With a detection threshold of 0.7 mm, the error detection rate on dwell position is 22% at 0.5 mm, 96% at 1 mm, and 100% at and beyond 1.5 mm. On dwell time with a dwell time threshold of 0.1 s, it is 90% at 0.2 s and 100% at and beyond 0.3 s. Conclusions: The proposed HDR-BT phantom and instrumented applicator have been tested and their main characteristics have been evaluated. These systems perform unsupervised measurements and analysis without prior treatment plan information. They allow independent verification of dwell position and time with accuracy of measurements comparable with other similar systems reported in the literature.« less

Improved electromagnetic tracking for catheter path reconstruction with application in high-dose-rate brachytherapy.

PubMed

Lugez, Elodie; Sadjadi, Hossein; Joshi, Chandra P; Akl, Selim G; Fichtinger, Gabor

2017-04-01

Electromagnetic (EM) catheter tracking has recently been introduced in order to enable prompt and uncomplicated reconstruction of catheter paths in various clinical interventions. However, EM tracking is prone to measurement errors which can compromise the outcome of the procedure. Minimizing catheter tracking errors is therefore paramount to improve the path reconstruction accuracy. An extended Kalman filter (EKF) was employed to combine the nonlinear kinematic model of an EM sensor inside the catheter, with both its position and orientation measurements. The formulation of the kinematic model was based on the nonholonomic motion constraints of the EM sensor inside the catheter. Experimental verification was carried out in a clinical HDR suite. Ten catheters were inserted with mean curvatures varying from 0 to [Formula: see text] in a phantom. A miniaturized Ascension (Burlington, Vermont, USA) trakSTAR EM sensor (model 55) was threaded within each catheter at various speeds ranging from 7.4 to [Formula: see text]. The nonholonomic EKF was applied on the tracking data in order to statistically improve the EM tracking accuracy. A sample reconstruction error was defined at each point as the Euclidean distance between the estimated EM measurement and its corresponding ground truth. A path reconstruction accuracy was defined as the root mean square of the sample reconstruction errors, while the path reconstruction precision was defined as the standard deviation of these sample reconstruction errors. The impacts of sensor velocity and path curvature on the nonholonomic EKF method were determined. Finally, the nonholonomic EKF catheter path reconstructions were compared with the reconstructions provided by the manufacturer's filters under default settings, namely the AC wide notch and the DC adaptive filter. With a path reconstruction accuracy of 1.9 mm, the nonholonomic EKF surpassed the performance of the manufacturer's filters (2.4 mm) by 21% and the raw EM measurements (3.5 mm) by 46%. Similarly, with a path reconstruction precision of 0.8 mm, the nonholonomic EKF surpassed the performance of the manufacturer's filters (1.0 mm) by 20% and the raw EM measurements (1.7 mm) by 53%. Path reconstruction accuracies did not follow an apparent trend when varying the path curvature and sensor velocity; instead, reconstruction accuracies were predominantly impacted by the position of the EM field transmitter ([Formula: see text]). The advanced nonholonomic EKF is effective in reducing EM measurement errors when reconstructing catheter paths, is robust to path curvature and sensor speed, and runs in real time. Our approach is promising for a plurality of clinical procedures requiring catheter reconstructions, such as cardiovascular interventions, pulmonary applications (Bender et al. in medical image computing and computer-assisted intervention-MICCAI 99. Springer, Berlin, pp 981-989, 1999), and brachytherapy.

Artificial neural network based gynaecological image-guided adaptive brachytherapy treatment planning correction of intra-fractional organs at risk dose variation.

PubMed

Jaberi, Ramin; Siavashpour, Zahra; Aghamiri, Mahmoud Reza; Kirisits, Christian; Ghaderi, Reza

2017-12-01

Intra-fractional organs at risk (OARs) deformations can lead to dose variation during image-guided adaptive brachytherapy (IGABT). The aim of this study was to modify the final accepted brachytherapy treatment plan to dosimetrically compensate for these intra-fractional organs-applicators position variations and, at the same time, fulfilling the dosimetric criteria. Thirty patients with locally advanced cervical cancer, after external beam radiotherapy (EBRT) of 45-50 Gy over five to six weeks with concomitant weekly chemotherapy, and qualified for intracavitary high-dose-rate (HDR) brachytherapy with tandem-ovoid applicators were selected for this study. Second computed tomography scan was done for each patient after finishing brachytherapy treatment with applicators in situ. Artificial neural networks (ANNs) based models were used to predict intra-fractional OARs dose-volume histogram parameters variations and propose a new final plan. A model was developed to estimate the intra-fractional organs dose variations during gynaecological intracavitary brachytherapy. Also, ANNs were used to modify the final brachytherapy treatment plan to compensate dosimetrically for changes in 'organs-applicators', while maintaining target dose at the original level. There are semi-automatic and fast responding models that can be used in the routine clinical workflow to reduce individually IGABT uncertainties. These models can be more validated by more patients' plans to be able to serve as a clinical tool.

A randomized trial of the effect of training in relaxation and guided imagery techniques in improving psychological and quality-of-life indices for gynecologic and breast brachytherapy patients.

PubMed

León-Pizarro, Concha; Gich, Ignasi; Barthe, Emma; Rovirosa, Angeles; Farrús, Blanca; Casas, Francesc; Verger, Eugènia; Biete, Albert; Craven-Bartle, Jordi; Sierra, Jordi; Arcusa, Angeles

2007-11-01

The randomized study aimed to determine the efficacy of psychological intervention consisting of relaxation and guided imagery to reduce anxiety and depression in gynecologic and breast cancer patients undergoing brachytherapy during hospitalization. Sixty-six patients programmed to receive brachytherapy in two hospitals in Barcelona (Spain) were included in this study. The patients were randomly allocated to either the study group (n=32) or the control group (n=34). Patients in both groups received training regarding brachytherapy, but only study group patients received training in relaxation and guided imagery. After collection of sociodemographic data, all patients were given a set of questionnaires on anxiety and depression: the Hospital Anxiety and Depression Scale (HADS), and on quality of life: Cuestionario de Calidad de Vida QL-CA-AFex (CCV), prior to, during and after brachytherapy. The study group demonstrated a statistically significant reduction in anxiety (p=0.008), depression (p=0.03) and body discomfort (p=0.04) compared with the control group. The use of relaxation techniques and guided imagery is effective in reducing the levels of anxiety, depression and body discomfort in patients who must remain isolated while undergoing brachytherapy. This simple and inexpensive intervention enhances the psychological wellness in patients undergoing brachytherapy.State: This study has passed Ethical Committee review.

HDR-192Ir intraluminal brachytherapy in treatment of malignant obstructive jaundice

PubMed Central

Chen, Yi; Wang, Xiao-Lin; Yan, Zhi-Ping; Cheng, Jie-Min; Wang, Jian-Hua; Gong, Gao-Quan; Qian, Sheng; Luo, Jian-Jun; Liu, Qing-Xin

2004-01-01

AIM: To determine the feasibility and safety of intraluminal brachytherapy in treatment of malignant obstructive jaundice (MOJ) and to evaluate the clinical effect of intraluminal brachytherapy on stent patency and patient survival. METHODS: Thirty-four patients with MOJ were included in this study. Having biliary stent placed, all patients were classified into intraluminal brachytherapy group (group A, n = 14) and control group (group B, n = 20) according to their own choice. Intraluminal brachytherapy regimen included: HDR-192Ir was used in the therapy, fractional doses of 4-7 Gy were given every 3-6 d for 3-4 times, and standard points were established at 0.5-1.0 cm. Some patients of both groups received transcatheter arterial chemoembolization (TACE) after stent placement. RESULTS: In group A, the success rate of intraluminal brachytherapy was 98.0%, RTOG grade 1 acute radiation morbidity occurred in 3 patients, RTOG/EORTC grade 1 late radiation morbidity occurred in 1 patient. Mean stent patency of group A (12.6 mo) was significantly longer than that of group B (8.3 mo) (P < 0.05). There was no significant difference in the mean survival (9.4 mo vs 6.0 mo) between the two groups. CONCLUSION: HDR-192Ir intraluminal brachytherapy is a safe palliative therapy in treating MOJ, and it may prolong stent patency and has the potentiality of extending survival of patients with MOJ. PMID:15526374

Benefit of Adjuvant Brachytherapy Versus External Beam Radiation for Early Breast Cancer: Impact of Patient Stratification on Breast Preservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Grace L.; Jiang, Jing; Buchholz, Thomas A.

Purpose: Brachytherapy after lumpectomy is an increasingly popular breast cancer treatment, but data concerning its effectiveness are conflicting. Recently proposed “suitability” criteria guiding patient selection for brachytherapy have never been empirically validated. Methods: Using the Surveillance, Epidemiology, and End Results–Medicare linked database, we compared women aged 66 years or older with invasive breast cancer (n=28,718) or ductal carcinoma in situ (n=7229) diagnosed from 2002 to 2007, treated with lumpectomy alone, brachytherapy, or external beam radiation therapy (EBRT). The likelihood of breast preservation, measured by subsequent mastectomy risk, was compared by use of multivariate proportional hazards, further stratified by American Societymore » for Radiation Oncology (ASTRO) brachytherapy suitability groups. We compared 1-year postoperative complications using the χ{sup 2} test and 5-year local toxicities using the log-rank test. Results: For patients with invasive cancer, the 5-year subsequent mastectomy risk was 4.7% after lumpectomy alone (95% confidence interval [CI], 4.1%-5.4%), 2.8% after brachytherapy (95% CI, 1.8%-4.3%), and 1.3% after EBRT (95% CI, 1.1%-1.5%) (P<.001). Compared with lumpectomy alone, brachytherapy achieved a more modest reduction in adjusted risk (hazard ratio [HR], 0.61; 95% CI, 0.40-0.94) than achieved with EBRT (HR, 0.22; 95% CI, 0.18-0.28). Relative risks did not differ when stratified by ASTRO suitability group (P=.84 for interaction), although ASTRO “suitable” patients did show a low absolute subsequent mastectomy risk, with a minimal absolute difference in risk after brachytherapy (1.6%; 95% CI, 0.7%-3.5%) versus EBRT (0.8%; 95% CI, 0.6%-1.1%). For patients with ductal carcinoma in situ, EBRT maintained a reduced risk of subsequent mastectomy (HR, 0.40; 95% CI, 0.28-0.55; P<.001), whereas the small number of patients treated with brachytherapy (n=179) precluded definitive comparison with lumpectomy alone. In all patients, brachytherapy showed a higher postoperative infection risk (16.5% vs 9.9% after lumpectomy alone vs 11.4% after EBRT, P<.001); higher incidence of breast pain (22.9% vs 11.2% vs 16.7%, P<.001); and higher incidence of fat necrosis (15.3% vs 5.3% vs 7.7%, P<.001). Conclusions: In this study era, brachytherapy showed lesser breast preservation benefit compared with EBRT. Suitability criteria predicted differential absolute, but not relative, benefit in patients with invasive cancer.« less

A comparison study on various low energy sources in interstitial prostate brachytherapy

PubMed Central

Bakhshabadi, Mahdi; Ghorbani, Mahdi; Knaup, Courtney; Meigooni, Ali S.

2016-01-01

Purpose Low energy sources are routinely used in prostate brachytherapy. 125I is one of the most commonly used sources. Low energy 131Cs source was introduced recently as a brachytherapy source. The aim of this study is to compare dose distributions of 125I, 103Pd, and 131Cs sources in interstitial brachytherapy of prostate. Material and methods ProstaSeed 125I brachytherapy source was simulated using MCNPX Monte Carlo code. Additionally, two hypothetical sources of 103Pd and 131Cs were simulated with the same geometry as the ProstaSeed 125I source, while having their specific emitted gamma spectra. These brachytherapy sources were simulated with distribution of forty-eight seeds in a phantom including prostate. The prostate was considered as a sphere with radius of 1.5 cm. Absolute and relative dose rates were obtained in various distances from the source along the transverse and longitudinal axes inside and outside the tumor. Furthermore, isodose curves were plotted around the sources. Results Analyzing the initial dose profiles for various sources indicated that with the same time duration and air kerma strength, 131Cs delivers higher dose to tumor. However, relative dose rate inside the tumor is higher and outside the tumor is lower for the 103Pd source. Conclusions The higher initial absolute dose in cGy/(h.U) of 131Cs brachytherapy source is an advantage of this source over the others. The higher relative dose inside the tumor and lower relative dose outside the tumor for the 103Pd source are advantages of this later brachytherapy source. Based on the total dose the 125I source has advantage over the others due to its longer half-life. PMID:26985200

A comparison study on various low energy sources in interstitial prostate brachytherapy.

PubMed

Bakhshabadi, Mahdi; Ghorbani, Mahdi; Khosroabadi, Mohsen; Knaup, Courtney; Meigooni, Ali S

2016-02-01

Low energy sources are routinely used in prostate brachytherapy. (125)I is one of the most commonly used sources. Low energy (131)Cs source was introduced recently as a brachytherapy source. The aim of this study is to compare dose distributions of (125)I, (103)Pd, and (131)Cs sources in interstitial brachytherapy of prostate. ProstaSeed (125)I brachytherapy source was simulated using MCNPX Monte Carlo code. Additionally, two hypothetical sources of (103)Pd and (131)Cs were simulated with the same geometry as the ProstaSeed (125)I source, while having their specific emitted gamma spectra. These brachytherapy sources were simulated with distribution of forty-eight seeds in a phantom including prostate. The prostate was considered as a sphere with radius of 1.5 cm. Absolute and relative dose rates were obtained in various distances from the source along the transverse and longitudinal axes inside and outside the tumor. Furthermore, isodose curves were plotted around the sources. Analyzing the initial dose profiles for various sources indicated that with the same time duration and air kerma strength, (131)Cs delivers higher dose to tumor. However, relative dose rate inside the tumor is higher and outside the tumor is lower for the (103)Pd source. The higher initial absolute dose in cGy/(h.U) of (131)Cs brachytherapy source is an advantage of this source over the others. The higher relative dose inside the tumor and lower relative dose outside the tumor for the (103)Pd source are advantages of this later brachytherapy source. Based on the total dose the (125)I source has advantage over the others due to its longer half-life.

A novel applicator design for intracavitary brachytherapy of the nasopharynx: Simulated reconstruction, image-guided adaptive brachytherapy planning, and dosimetry.

PubMed

Bacorro, Warren R; Agas, Ryan Anthony F; Cabrera, Stellar Marie R; Bojador, Maureen R; Sogono, Paolo G; Mejia, Michael Benedict A; Sy Ortin, Teresa T

2018-05-11

In nasopharyngeal cancer, brachytherapy is given as boost in primary treatment or as salvage for recurrent or persistent disease. The Rotterdam nasopharyngeal applicator (RNA) allows for suboptimal reduction of soft palate radiation dose, based on image-guided brachytherapy plans. Building on the RNA, we propose a novel design, the Benavides nasopharyngeal applicator (BNA). The virtual BNA was reconstructed on two cases (one T1, one T2) previously treated with intracavitary brachytherapy using the RNA. Dose was prescribed to the high-risk clinical target volumes (CTVs) and optimization was such that high-risk CTV D90 ≥ 100% of prescribed dose (PD), intermediate-risk-CTV D90 ≥ 75% PD, and soft palate D2cc ≤ 120% PD. The optimized RNA and BNA image-guided brachytherapy plans were compared in terms of CTV coverage and organs-at-risk sparing. Optimization objectives were more easily met with the BNA. For the T1 case, all three planning objectives were easily achieved in both the RNA and BNA, but with 18-19% lower soft palate doses with the BNA. For the T2 case, the CTV planning objectives were achieved in both the RNA and BNA, but the soft palate constraint was only achieved with the BNA, with 38-41% lower soft palate doses. Compared to the RNA, the BNA permits easier optimization and improves therapeutic ratio by a significant reduction of soft palate doses, based on simulation using a proposed system for CTV/organs-at-risk delineation, prescription, and optimization for image-guided adaptive brachytherapy. Clinical piloting using a prototype is necessary to evaluate its feasibility and utility. Copyright © 2018 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Methods for prostate stabilization during transperineal LDR brachytherapy.

PubMed

Podder, Tarun; Sherman, Jason; Rubens, Deborah; Messing, Edward; Strang, John; Ng, Wan-Sing; Yu, Yan

2008-03-21

In traditional prostate brachytherapy procedures for a low-dose-rate (LDR) radiation seed implant, stabilizing needles are first inserted to provide some rigidity and support to the prostate. Ideally this will provide better seed placement and an overall improved treatment. However, there is much speculation regarding the effectiveness of using regular brachytherapy needles as stabilizers. In this study, we explored the efficacy of two types of needle geometries (regular brachytherapy needle and hooked needle) and several clinically feasible configurations of the stabilization needles. To understand and assess the prostate movement during seed implantation, we collected in vivo data from patients during actual brachytherapy procedures. In vitro experimentation with tissue-equivalent phantoms allowed us to further understand the mechanics behind prostate stabilization. We observed superior stabilization with the hooked needles compared to the regular brachytherapy needles (more than 40% in bilateral parallel needle configuration). Prostate movement was also reduced significantly when regular brachytherapy needles were in an angulated configuration as compared to the parallel configuration (more than 60%). When the hooked needles were angulated for stabilization, further reduction in prostate displacement was observed. In general, for convenience of dosimetric planning and to avoid needle collision, all needles are desired to be in a parallel configuration. In this configuration, hooked needles provide improved stabilization of the prostate. On the other hand, both regular and hooked needles appear to be equally effective in reducing prostate movement when they are in angulated configurations, which will be useful in seed implantation using a robotic system. We have developed nonlinear spring-damper model for the prostate movement which can be used for adapting dosimetric planning during brachytherapy as well as for developing more realistic haptic devices and training simulators.

Transition from LDR to HDR brachytherapy for cervical cancer: Evaluation of tumor control, survival, and toxicity.

PubMed

Romano, K D; Pugh, K J; Trifiletti, D M; Libby, B; Showalter, T N

In 2012, our institution transitioned from low-dose-rate (LDR) brachytherapy to high dose-rate (HDR) brachytherapy. We report clinical outcomes after brachytherapy for cervical cancer at our institution over a continuous 10-year period. From 2004 to 2014, 258 women (184 LDR and 74 HDR) were treated with tandem and ovoid brachytherapy in the multidisciplinary management of International Federation of Gynecology and Obstetrics Stages IA-IVB cervical cancer. Clinical and treatment-related prognostic factors including age, stage, smoking status, relevant doses, and toxicity data were recorded. Median followup for the LDR and HDR groups was 46 months and 12 months, respectively. The majority of patients (92%) received external beam radiotherapy as well as concurrent chemotherapy (83%) before the start of brachytherapy. For all stages, the 1-year local control and overall survival (OS) rates were comparable between the LDR and HDR groups (87% vs. 81%, p = 0.12; and 75% vs. 85%, p = 0.16), respectively. Factors associated with OS on multivariate analysis include age, stage, and nodal involvement. On multivariate analysis, severe toxicity (acute or chronic) was higher with HDR than LDR (24% vs. 10%, p = 0.04). Additional prognostic factors associated with increased severe toxicity include former/current smokers and total dose to lymph nodes. This comparative retrospective analysis of a large cohort of women treated with brachytherapy demonstrates no significant difference in OS or local control between the LDR and HDR. Acute and chronic toxicity increased shortly after the implementation of HDR, highlighting the importance of continued refinement of HDR methods, including integrating advanced imaging. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Development of an adjoint sensitivity field-based treatment-planning technique for the use of newly designed directional LDR sources in brachytherapy.

PubMed

Chaswal, V; Thomadsen, B R; Henderson, D L

2012-02-21

The development and application of an automated 3D greedy heuristic (GH) optimization algorithm utilizing the adjoint sensitivity fields for treatment planning to assess the advantage of directional interstitial prostate brachytherapy is presented. Directional and isotropic dose kernels generated using Monte Carlo simulations based on Best Industries model 2301 I-125 source are utilized for treatment planning. The newly developed GH algorithm is employed for optimization of the treatment plans for seven interstitial prostate brachytherapy cases using mixed sources (directional brachytherapy) and using only isotropic sources (conventional brachytherapy). All treatment plans resulted in V100 > 98% and D90 > 45 Gy for the target prostate region. For the urethra region, the D10(Ur), D90(Ur) and V150(Ur) and for the rectum region the V100cc, D2cc, D90(Re) and V90(Re) all are reduced significantly when mixed sources brachytherapy is used employing directional sources. The simulations demonstrated that the use of directional sources in the low dose-rate (LDR) brachytherapy of the prostate clearly benefits in sparing the urethra and the rectum sensitive structures from overdose. The time taken for a conventional treatment plan is less than three seconds, while the time taken for a mixed source treatment plan is less than nine seconds, as tested on an Intel Core2 Duo 2.2 GHz processor with 1GB RAM. The new 3D GH algorithm is successful in generating a feasible LDR brachytherapy treatment planning solution with an extra degree of freedom, i.e. directionality in very little time.

Development of an adjoint sensitivity field-based treatment-planning technique for the use of newly designed directional LDR sources in brachytherapy

NASA Astrophysics Data System (ADS)

Chaswal, V.; Thomadsen, B. R.; Henderson, D. L.

2012-02-01

The development and application of an automated 3D greedy heuristic (GH) optimization algorithm utilizing the adjoint sensitivity fields for treatment planning to assess the advantage of directional interstitial prostate brachytherapy is presented. Directional and isotropic dose kernels generated using Monte Carlo simulations based on Best Industries model 2301 I-125 source are utilized for treatment planning. The newly developed GH algorithm is employed for optimization of the treatment plans for seven interstitial prostate brachytherapy cases using mixed sources (directional brachytherapy) and using only isotropic sources (conventional brachytherapy). All treatment plans resulted in V100 > 98% and D90 > 45 Gy for the target prostate region. For the urethra region, the D10Ur, D90Ur and V150Ur and for the rectum region the V100cc, D2cc, D90Re and V90Re all are reduced significantly when mixed sources brachytherapy is used employing directional sources. The simulations demonstrated that the use of directional sources in the low dose-rate (LDR) brachytherapy of the prostate clearly benefits in sparing the urethra and the rectum sensitive structures from overdose. The time taken for a conventional treatment plan is less than three seconds, while the time taken for a mixed source treatment plan is less than nine seconds, as tested on an Intel Core2 Duo 2.2 GHz processor with 1GB RAM. The new 3D GH algorithm is successful in generating a feasible LDR brachytherapy treatment planning solution with an extra degree of freedom, i.e. directionality in very little time.

GGEMS-Brachy: GPU GEant4-based Monte Carlo simulation for brachytherapy applications

NASA Astrophysics Data System (ADS)

Lemaréchal, Yannick; Bert, Julien; Falconnet, Claire; Després, Philippe; Valeri, Antoine; Schick, Ulrike; Pradier, Olivier; Garcia, Marie-Paule; Boussion, Nicolas; Visvikis, Dimitris

2015-07-01

In brachytherapy, plans are routinely calculated using the AAPM TG43 formalism which considers the patient as a simple water object. An accurate modeling of the physical processes considering patient heterogeneity using Monte Carlo simulation (MCS) methods is currently too time-consuming and computationally demanding to be routinely used. In this work we implemented and evaluated an accurate and fast MCS on Graphics Processing Units (GPU) for brachytherapy low dose rate (LDR) applications. A previously proposed Geant4 based MCS framework implemented on GPU (GGEMS) was extended to include a hybrid GPU navigator, allowing navigation within voxelized patient specific images and analytically modeled 125I seeds used in LDR brachytherapy. In addition, dose scoring based on track length estimator including uncertainty calculations was incorporated. The implemented GGEMS-brachy platform was validated using a comparison with Geant4 simulations and reference datasets. Finally, a comparative dosimetry study based on the current clinical standard (TG43) and the proposed platform was performed on twelve prostate cancer patients undergoing LDR brachytherapy. Considering patient 3D CT volumes of 400  × 250  × 65 voxels and an average of 58 implanted seeds, the mean patient dosimetry study run time for a 2% dose uncertainty was 9.35 s (≈500 ms 10-6 simulated particles) and 2.5 s when using one and four GPUs, respectively. The performance of the proposed GGEMS-brachy platform allows envisaging the use of Monte Carlo simulation based dosimetry studies in brachytherapy compatible with clinical practice. Although the proposed platform was evaluated for prostate cancer, it is equally applicable to other LDR brachytherapy clinical applications. Future extensions will allow its application in high dose rate brachytherapy applications.

[Brachytherapy training].

PubMed

Hannoun-Lévi, J-M; Marchesi, V; Peiffert, D

2013-04-01

Treatment technique training needs theoretical and practical knowledge allowing proposing the right treatment for the right patient, but also allowing performing the technical gesture in the best conditions for an optimal result with a maximal security. The evolution of the brachytherapy techniques needs the set up of specific theoretical and practical training sessions. The present article focuses on the importance of the brachytherapy training as well as the different means currently available for the young radiation oncologist community for perfecting their education. National and international trainings are presented. The role of the simulation principle in the frame of brachytherapy is also discussed. Even if brachytherapy is not always an easy technique, its efficacy and its medico-economical impact need to be passed down to motivated students with the implementation of relevant educational means. Copyright © 2013 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Fast dose kernel interpolation using Fourier transform with application to permanent prostate brachytherapy dosimetry.

PubMed

Liu, Derek; Sloboda, Ron S

2014-05-01

Boyer and Mok proposed a fast calculation method employing the Fourier transform (FT), for which calculation time is independent of the number of seeds but seed placement is restricted to calculation grid points. Here an interpolation method is described enabling unrestricted seed placement while preserving the computational efficiency of the original method. The Iodine-125 seed dose kernel was sampled and selected values were modified to optimize interpolation accuracy for clinically relevant doses. For each seed, the kernel was shifted to the nearest grid point via convolution with a unit impulse, implemented in the Fourier domain. The remaining fractional shift was performed using a piecewise third-order Lagrange filter. Implementation of the interpolation method greatly improved FT-based dose calculation accuracy. The dose distribution was accurate to within 2% beyond 3 mm from each seed. Isodose contours were indistinguishable from explicit TG-43 calculation. Dose-volume metric errors were negligible. Computation time for the FT interpolation method was essentially the same as Boyer's method. A FT interpolation method for permanent prostate brachytherapy TG-43 dose calculation was developed which expands upon Boyer's original method and enables unrestricted seed placement. The proposed method substantially improves the clinically relevant dose accuracy with negligible additional computation cost, preserving the efficiency of the original method.

Online gamma-camera imaging of 103Pd seeds (OGIPS) for permanent breast seed implantation

NASA Astrophysics Data System (ADS)

Ravi, Ananth; Caldwell, Curtis B.; Keller, Brian M.; Reznik, Alla; Pignol, Jean-Philippe

2007-09-01

Permanent brachytherapy seed implantation is being investigated as a mode of accelerated partial breast irradiation for early stage breast cancer patients. Currently, the seeds are poorly visualized during the procedure making it difficult to perform a real-time correction of the implantation if required. The objective was to determine if a customized gamma-camera can accurately localize the seeds during implantation. Monte Carlo simulations of a CZT based gamma-camera were used to assess whether images of suitable quality could be derived by detecting the 21 keV photons emitted from 74 MBq 103Pd brachytherapy seeds. A hexagonal parallel hole collimator with a hole length of 38 mm, hole diameter of 1.2 mm and 0.2 mm septa, was modeled. The design of the gamma-camera was evaluated on a realistic model of the breast and three layers of the seed distribution (55 seeds) based on a pre-implantation CT treatment plan. The Monte Carlo simulations showed that the gamma-camera was able to localize the seeds with a maximum error of 2.0 mm, using only two views and 20 s of imaging. A gamma-camera can potentially be used as an intra-procedural image guidance system for quality assurance for permanent breast seed implantation.

Physics of vascular brachytherapy.

PubMed

Jani, S K

1999-08-01

Basic physics plays an important role in understanding the clinical utility of radioisotopes in brachytherapy. Vascular brachytherapy is a very unique application of localized radiation in that dose levels very close to the source are employed to treat tissues within the arterial wall. This article covers basic physics of radioactivity and differentiates between beta and gamma radiations. Physical parameters such as activity, half-life, exposure and absorbed dose have been explained. Finally, the dose distribution around a point source and a linear source is described. The principles of basic physics are likely to play an important role in shaping the emerging technology and its application in vascular brachytherapy.

Technology Insight: Combined external-beam radiation therapy and brachytherapy in the management of prostate cancer.

PubMed

Hurwitz, Mark D

2008-11-01

External-beam radiation therapy (EBRT) combined with brachytherapy is an attractive treatment option for selected patients with clinically localized prostate cancer. This therapeutic strategy offers dosimetric coverage if local-regional microscopic disease is present and provides a highly conformal boost of radiation to the prostate and immediate surrounding tissues. Either low-dose-rate (LDR) permanent brachytherapy or high-dose-rate (HDR) temporary brachytherapy can be combined with EBRT; such combined-modality therapy (CMT) is typically used to treat patients with intermediate-risk to high-risk, clinically localized disease. Controversy persists with regard to indications for CMT, choice of LDR or HDR boost, isotope selection for LDR, and integration of EBRT and brachytherapy. Initial findings from prospective, multicenter trials of CMT support the feasibility of this strategy. Updated results from these trials as well as those of ongoing and new phase III trials should help to define the role of CMT in the management of prostate cancer. In the meantime, long-term expectations for outcomes of CMT are based largely on the experience of single institutions, which demonstrate that CMT with EBRT and either LDR or HDR brachytherapy can provide freedom from disease recurrence with acceptable toxicity.

Outcomes and toxicities in patients with intermediate-risk prostate cancer treated with brachytherapy alone or brachytherapy and supplemental external beam radiation therapy.

PubMed

Schlussel Markovic, Emily; Buckstein, Michael; Stone, Nelson N; Stock, Richard G

2018-05-01

To evaluate the cancer control outcomes and long-term treatment-related morbidity of brachytherapy as well as combination brachytherapy and external beam radiation therapy (EBRT) in patients with intermediate-risk prostate cancer. A retrospective review was conducted in a prospectively collected database of patients with intermediate-risk prostate cancer who were treated either with brachytherapy or brachytherapy and EBRT, with or without androgen deprivation therapy (ADT), in the period 1990-2014. Urinary and erectile dysfunction symptoms were measured using the International Prostate Symptom Score (IPSS), the Mount Sinai erectile function scale and the Sexual Health Inventory for Men (SHIM). Cancer control endpoints included biochemical failure and development of distant metastases. All statistical analyses were carried out using the Statistical Package for Social Science (SPSS). Survival curves were calculated using Kaplan-Meier actuarial methods and compared using log-rank tests. Cox regression multivariate analyses were used to test the effect of multiple variables on treatment outcomes. A total of 902 patients were identified, with a median follow-up of 91 months. Of these, 390 received brachytherapy and 512 received combination therapy with EBRT. In patients with one intermediate-risk factor, the addition of EBRT did not significantly affect freedom from biochemical failure or distant metastases. Among patients with two or three intermediate-risk factors, added EBRT did not improve freedom from biochemical failure. Significant differences in late toxicity between patients treated with brachytherapy vs combination brachytherapy and EBRT were identified including urge incontinence (P < 0.001), haematuria (P < 0.001), dysuria (P < 0.001), and change in quality-of-life IPSS (P = 0.002). These symptoms were reported by patients at any point during treatment follow-up. Analysis of patients who were potent before treatment using actuarial methods showed that patients receiving combination therapy more frequently experienced loss of potency, as measured by the Mount Sinai erectile function scale (P = 0.040). Brachytherapy monotherapy results in equal biochemical and distant control in both patients with one and more than one intermediate-risk features. While no significant benefit was shown, we believe that the addition of EBRT may prevent recurrence in patients with multiple intermediate-risk features and should be considered. © 2018 The Authors BJU International © 2018 BJU International Published by John Wiley & Sons Ltd.

Novel use of ViewRay MRI guidance for high-dose-rate brachytherapy in the treatment of cervical cancer.

PubMed

Ko, Huaising C; Huang, Jessie Y; Miller, Jessica R; Das, Rupak K; Wallace, Charles R; De Costa, Anna-Maria A; Francis, David M; Straub, Margaret R; Anderson, Bethany M; Bradley, Kristin A

To characterize image quality and feasibility of using ViewRay MRI (VR)-guided brachytherapy planning for cervical cancer. Cervical cancer patients receiving intracavitary brachytherapy with tandem and ovoids, planned using 0.35T VR MRI at our institution, were included in this series. The high-risk clinical target volume (HR-CTV), visible gross tumor volume, bladder, sigmoid, bowel, and rectum contours for each fraction of brachytherapy were evaluated for dosimetric parameters. Typically, five brachytherapy treatments were planned using the T2 sequence on diagnostic MRI for the first and third fractions, and a noncontrast true fast imaging with steady-state precession sequence on VR or CT scan for the remaining fractions. Most patients received 5.5 Gy × 5 fractions using high-dose-rate Ir-192 following 45 Gy of whole-pelvis radiotherapy. The plan was initiated at 5.5 Gy to point A and subsequently optimized and prescribed to the HR-CTV. The goal equivalent dose in 2 Gy fractions for the combined external beam and brachytherapy dose was 85 Gy. Soft-tissue visualization using contrast-to-noise ratios to distinguish normal tissues from tumor at their interface was compared between diagnostic MRI, CT, and VR. One hundred and forty-two fractions of intracavitary brachytherapy were performed from April 2015 to January 2017 on 29 cervical cancer patients, ranging from stages IB1 to IVA. The median HR-CTV was 27.78 cc, with median D 90 HR-CTV of 6.1 Gy. The median time from instrument placement to start of treatment using VR was 65 min (scan time 2 min), compared to 105 min using diagnostic MRI (scan time 11 min) (t-test, p < 0.01). The contrast-to-noise ratio of tumor to cervix in both diagnostic MRI and VR had significantly higher values compared to CT (ANOVA and t-tests, p < 0.01). We report the first clinical use of VR-guided brachytherapy. Time to treatment using this approach was shorter compared to diagnostic MRI. VR also provided significant advantage in visualizing the tumor and cervix compared to CT. This presents a feasible and reliable manner to image and plan gynecologic brachytherapy. Copyright © 2018 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Artificial neural network based gynaecological image-guided adaptive brachytherapy treatment planning correction of intra-fractional organs at risk dose variation

PubMed Central

Jaberi, Ramin; Aghamiri, Mahmoud Reza; Kirisits, Christian; Ghaderi, Reza

2017-01-01

Purpose Intra-fractional organs at risk (OARs) deformations can lead to dose variation during image-guided adaptive brachytherapy (IGABT). The aim of this study was to modify the final accepted brachytherapy treatment plan to dosimetrically compensate for these intra-fractional organs-applicators position variations and, at the same time, fulfilling the dosimetric criteria. Material and methods Thirty patients with locally advanced cervical cancer, after external beam radiotherapy (EBRT) of 45-50 Gy over five to six weeks with concomitant weekly chemotherapy, and qualified for intracavitary high-dose-rate (HDR) brachytherapy with tandem-ovoid applicators were selected for this study. Second computed tomography scan was done for each patient after finishing brachytherapy treatment with applicators in situ. Artificial neural networks (ANNs) based models were used to predict intra-fractional OARs dose-volume histogram parameters variations and propose a new final plan. Results A model was developed to estimate the intra-fractional organs dose variations during gynaecological intracavitary brachytherapy. Also, ANNs were used to modify the final brachytherapy treatment plan to compensate dosimetrically for changes in ‘organs-applicators’, while maintaining target dose at the original level. Conclusions There are semi-automatic and fast responding models that can be used in the routine clinical workflow to reduce individually IGABT uncertainties. These models can be more validated by more patients’ plans to be able to serve as a clinical tool. PMID:29441094

Brachytherapy Using Elastin-Like Polypeptides with (131)I Inhibit Tumor Growth in Rabbits with VX2 Liver Tumor.

PubMed

Liu, Xinpei; Shen, Yiming; Zhang, Xuqian; Lin, Rui; Jia, Qiang; Chang, Yixiang; Liu, Wenge; Liu, Wentian

2016-10-01

Brachytherapy is a targeted type of radiotherapy utilized in the treatment of cancers. Elastin-like polypeptides are a unique class of genetically engineered peptide polymers that have several attractive properties for brachytherapy. To explore the feasibility and application of brachytherapy for VX2 liver tumor using elastin-like polypeptides with (131)I so as to provide reliable experimental evidence for a new promising treatment of liver cancer. Elastin-like polypeptide as carrier was labeled with (131)I using the iodogen method. Ten eligible rabbits with VX2 liver tumor were randomly divided into the treatment group (n = 5) and control group (n = 5). The treatment group received brachytherapy using elastin-like polypeptide with (131)I, and in the control group, elastin-like polypeptide was injected into the VX2 liver tumor as a control. Periodic biochemical and imaging surveillances were required to assess treatment efficacy. The stability of elastin-like polypeptide with (131)I in vitro was maintained at over 96.8 % for 96 h. Biochemistry and imaging indicated brachytherapy using elastin-like polypeptide with (131)I for liver tumor can improve liver function and inhibit tumor growth (P < 0.05). Elastin-like polypeptide can be an ideal carrier of (131)I and have high labeling efficiency, radiochemical purity and stability. Brachytherapy using elastin-like polypeptide with (131)I for liver tumor is a useful therapy that possesses high antitumor efficacy advantages.

Adherence to Vaginal Dilation Following High Dose Rate Brachytherapy for Endometrial Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedman, Lois C., E-mail: Lois.Friedman@UHhospitals.org; Abdallah, Rita; Schluchter, Mark

Purpose: We report demographic, clinical, and psychosocial factors associated with adherence to vaginal dilation and describe the sexual and marital or nonmarital dyadic functioning of women following high dose rate (HDR) brachytherapy for endometrial cancer. Methods and Materials: We retrospectively evaluated women aged 18 years or older in whom early-stage endometrial (IAgr3-IIB) cancers were treated by HDR intravaginal brachytherapy within the past 3.5 years. Women with or without a sexual partner were eligible. Patients completed questionnaires by mail or by telephone assessing demographic and clinical variables, adherence to vaginal dilation, dyadic satisfaction, sexual functioning, and health beliefs. Results: Seventy-eight ofmore » 89 (88%) eligible women with early-stage endometrial cancer treated with HDR brachytherapy completed questionnaires. Only 33% of patients were adherers, based on reporting having used a dilator more than two times per week in the first month following radiation. Nonadherers who reported a perceived change in vaginal dimension following radiation reported that their vaginas were subjectively smaller after brachytherapy (p = 0.013). Adherers reported more worry about their sex lives or lack thereof than nonadherers (p = 0.047). Patients reported considerable sexual dysfunction following completion of HDR brachytherapy. Conclusions: Adherence to recommendations for vaginal dilator use following HDR brachytherapy for endometrial cancer is poor. Interventions designed to educate women about dilator use benefit may increase adherence. Although sexual functioning was compromised, it is likely that this existed before having cancer for many women in our study.« less

MO-B-BRC-01: Introduction [Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prisciandaro, J.

2016-06-15

Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR ismore » U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.« less

Development of a TLD mailed system for remote dosimetry audit for (192)Ir HDR and PDR sources.

PubMed

Roué, Amélie; Venselaar, Jack L M; Ferreira, Ivaldo H; Bridier, André; Van Dam, Jan

2007-04-01

In the framework of an ESTRO ESQUIRE project, the BRAPHYQS Physics Network and the EQUAL-ESTRO laboratory have developed a procedure for checking the absorbed dose to water in the vicinity of HDR or PDR sources using a mailed TLD system. The methodology and the materials used in the procedure are based on the existing EQUAL-ESTRO external radiotherapy dose checks. A phantom for TLD postal dose assurance service, adapted to accept catheters from different HDR afterloaders, has been developed. The phantom consists of three PMMA tubes supporting catheters placed at 120 degrees around a central TLD holder. A study on the use of LiF powder type DTL 937 (Philitech) has been performed in order to establish the TLD calibration in dose-to-water at a given distance from (192)Ir source, as well as to determine all correction factors to convert the TLD reading into absorbed dose to water. The dosimetric audit is based on the comparison between the dose to water measured with the TL dosimeter and the dose calculated by the clinical TPS. Results of the audits are classified in four different levels depending on the ratio of the measured dose to the stated dose. The total uncertainty budget in the measurement of the absorbed dose to water using TLD near an (192)Ir HDR source, including TLD reading, correction factors and TLD calibration coefficient, is determined as 3.27% (1s). To validate the procedures, the external audit was first tested among the members of the BRAPHYQS Network. Since November 2004, the test has been made available for use by all European brachytherapy centres. To date, 11 centres have participated in the checks and the results obtained are very encouraging. Nevertheless, one error detected has shown the usefulness of this audit. A method of absorbed dose to water determination in the vicinity of an (192)Ir brachytherapy source was developed for the purpose of a mailed TL dosimetry system. The accuracy of the procedure was determined. This method allows a check of the whole dosimetry chain for this type of brachytherapy afterloading system and can easily be performed by mail to any institution in the European area and elsewhere. Such an external audit can be an efficient QC method complementary to internal quality control as it can reveal some errors which are not observable by other means.

[Valorisation of brachytherapy and medico-economic considerations].

PubMed

Pommier, P; Morelle, M; Millet-Lagarde, F; Peiffert, D; Gomez, F; Perrier, L

2013-04-01

Economic data in the literature for brachytherapy are still sparse and heterogeneous, with few controlled prospective studies and a perspective most often limited to those of the provider (health insurances). Moreover, these observation and conclusions are difficult to generalize in France. The prospective health economic studies performed in France in the framework of a national program to sustain innovative and costly therapies (STIC program) launched by the French cancer national institute are therefore of most importance. With the exception of prostate brachytherapy with permanent seeds, the valorisation of the brachytherapy activity by the French national health insurance does not take into account the degree of complexity and the real costs supported by health institutions (i.e. no specific valorisation for 3D image-based treatment planning and dose optimization and for the use of pulsed dose rate brachytherapy). Copyright © 2013 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

A Spanner in the works: the use of a new temporary urethral stent to relieve bladder outflow obstruction after prostate brachytherapy.

PubMed

Henderson, Alastair; Laing, Robert W; Langley, Stephen E M

2002-01-01

Assessment of the Spanner, a new temporary urethral stent to relieve bladder outflow obstruction and urinary symptoms after brachytherapy. Five patients with unusually severe urinary morbidity after (125)I brachytherapy were recruited. The mean time after implant was 40 days (range 25-90). Spanner intraprostatic stents were introduced using topical anesthetic without complication. All patients were able to void spontaneously with no post-void residual volume of urine. The flow rates increased in all cases (p=0.03) and the International Prostate Symptom Scores were significantly improved after stent insertion in all patients (p=0.03). All patients experienced some degree of pain or dysuria during stent use. Bladder outflow obstruction was effectively treated with the Spanner intraprostatic stent, however pain limited the use of the device in the early post-brachytherapy patient group. Pharmacotherapy, stent design modification, or smaller stent diameter may increase the utility of stents after brachytherapy.

Urethral toxicity after LDR brachytherapy: experience in Japan.

PubMed

Tanaka, Nobumichi; Asakawa, Isao; Hasegawa, Masatoshi; Fujimoto, Kiyohide

2015-01-01

Urinary toxicity is common after low-dose-rate (LDR) brachytherapy, and the resolution of urinary toxicity is a concern. In particular, urinary frequency is the most common adverse event among the urinary toxicities. We have previously reported that approximately 70% of patients experience urinary frequency during the first 6 months after seed implantation. Most urinary adverse events were classified as Grade 1, and Grade 2 or higher adverse events were rare. The incidence of urinary retention was approximately 2-4%. A high International Prostate Symptom Score before seed implantation was an independent predictor of acute urinary toxicity of Grade 2 or higher. Several previous reports from the United States also supported this trend. In Japan, LDR brachytherapy was legally approved in 2003. A nationwide prospective cohort study entitled Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 Seed Implantation was initiated in July 2005. It is an important issue to limit urinary toxicities in patients who undergo LDR brachytherapy. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Real-time photoacoustic imaging of prostate brachytherapy seeds using a clinical ultrasound system.

PubMed

Kuo, Nathanael; Kang, Hyun Jae; Song, Danny Y; Kang, Jin U; Boctor, Emad M

2012-06-01

Prostate brachytherapy is a popular prostate cancer treatment option that involves the permanent implantation of radioactive seeds into the prostate. However, contemporary brachytherapy procedure is limited by the lack of an imaging system that can provide real-time seed-position feedback. While many other imaging systems have been proposed, photoacoustic imaging has emerged as a potential ideal modality to address this need, since it could easily be incorporated into the current ultrasound system used in the operating room. We present such a photoacoustic imaging system built around a clinical ultrasound system to achieve the task of visualizing and localizing seeds. We performed several experiments to analyze the effects of various parameters on the appearance of brachytherapy seeds in photoacoustic images. We also imaged multiple seeds in an ex vivo dog prostate phantom to demonstrate the possibility of using this system in a clinical setting. Although still in its infancy, these initial results of a photoacoustic imaging system for the application of prostate brachytherapy seed localization are highly promising.

Targeting MRS-Defined Dominant Intraprostatic Lesions with Inverse-Planned High Dose Rate Brachytherapy. Addendum

DTIC Science & Technology

2009-06-01

imagining) into the HDR brachytherapy treatment planning has been demonstrated. Using the inverse planning program IPSA , dose escalation of target...Principles and Clinical Applications of IPSA ; Nucletron International Physics Seminar, Vaals, Netherlands, Sept 13-16, 2006. 7 IPSA ...experience with IPSA for prostate cancer treatment in HDR Brachytherapy, 4ième séminaire francophone de curiethérapie, Arcachon, France, June 15, 2006

Disease-specific survival following the brachytherapy management of prostate cancer.

PubMed

Stock, Richard G; Cesaretti, Jamie A; Stone, Nelson N

2006-03-01

To determine disease-specific survival (DSS) and associated predictive factors after prostate brachytherapy. A total of 1561 patients underwent brachytherapy for prostate cancer from 1990 to 2004 (median follow-up, 3.8 years). Treatment included brachytherapy alone (n = 634), brachytherapy and hormonal therapy (n = 420), and implant and external beam therapy (n = 507). The DSS and overall survival rates at 10 years were 96% and 74%, respectively. Gleason score significantly impacted DSS, with 10-year rates of 98%, 91%, and 92% for scores of < or = 6, 7, and > or = 8, respectively (p < 0.0001). Multivariate analysis revealed that PSA status after treatment had the most significant effect on DSS. Ten-year DSS rates were 100%, 52%, and 98%, respectively for patients without PSA failure (n = 1430), failure with a doubling time (DT) < or = 10 months (n = 64), and failure with a DT > 10 months (n = 67), respectively (p < 0.0001). In patients with PSA failure, DSS rates were 30%, 67%, and 98%, for those with DT < or = 6 months, > 6-10 months, and > 10 months, respectively (p < 0.0001). The 10-year DSS rate supports the efficacy of brachytherapy. Patients dying with disease within 10 years after treatment harbor inherently aggressive cancer with high Gleason scores and short DT.

Sexual function and quality of life in gynecological cancer pre- and post-short-term brachytherapy: a prospective study.

PubMed

Zomkowski, Kamilla; Toryi, Ariana Machado; Sacomori, Cinara; Dias, Mirella; Sperandio, Fabiana Flores

2016-10-01

To evaluate the sexual function and quality of life pre- and post-gynecological cancer treatment with high-dose rate brachytherapy in the short term. This is a descriptive and prospective study involving 20 women diagnosed with gynecological cancer aged between 18 and 70 years, resident in Florianopolis and the surrounding region. We used the Quality of Life Questionnaire Core-30 (QLQ-C30) 3.0 to assess quality of life pre- and post-brachytherapy treatment and the Female Sexual Function Index (FSFI) to assess sexual function. Regarding quality of life, significant worsening was observed for the items loss of appetite (p = 0.002) and diarrhea (p = 0.045) from pre- to post-brachytherapy treatment, whereas constipation (p = 0.013) improved. For sexual function, the statistical difference was found exclusively in the domain of lubrication reduction (p = 0.046). Only nine women were sexually active before and after brachytherapy treatment. There was a worsening of quality of life in comparing pre- and post-evaluations related to gastrointestinal symptoms over a period equivalent to 40 days. Regarding sexual function, lack of lubrication was identified in short-term post-gynecological cancer brachytherapy.

Brachytherapy of prostate cancer after colectomy for colorectal cancer: pilot experience.

PubMed

Koutrouvelis, Panos G; Theodorescu, Dan; Katz, Stuart; Lailas, Niko; Hendricks, Fred

2005-01-01

We present a method of brachytherapy for prostate cancer using a 3-dimensional stereotactic system and computerized tomography guidance in patients without a rectum due to previous treatment for colorectal cancer. From June 1994 to November 2003 a cohort of 800 patients were treated with brachytherapy for prostate cancer. Four patients had previously been treated for colorectal cancer with 4,500 cGy external beam radiation therapy, abdominoperineal resection and chemotherapy, while 1 underwent abdominoperineal resection alone for ulcerative colitis. Because of previous radiation therapy, these patients were not candidates for salvage external beam radiation therapy or radical prostatectomy and they had no rectum for transrectal ultrasound guided transperineal brachytherapy or cryotherapy. A previously described, 3-dimensional stereotactic system was used for brachytherapy in these patients. The prescribed radiation dose was 120 to 144 Gy with iodine seeds in rapid strand format. Patient followup included clinical examination and serum prostate specific antigen measurement. Average followup was 18.6 months. Four patients had excellent biochemical control, while 1 had biochemical failure. Patients did not experience any gastrointestinal morbidity. One patient had a stricture of the distal ureter, requiring a stent. Three-dimensional computerized tomography guided brachytherapy for prostate cancer in patients with a history of colorectal cancer who have no rectum is a feasible method of treatment.

Introduction of novel 3D-printed superficial applicators for high-dose-rate skin brachytherapy.

PubMed

Jones, Emma-Louise; Tonino Baldion, Anna; Thomas, Christopher; Burrows, Tom; Byrne, Nick; Newton, Victoria; Aldridge, Sarah

Custom-made surface mold applicators often allow more flexibility when carrying out skin brachytherapy, particularly for small treatment areas with high surface obliquity. They can, however, be difficult to manufacture, particularly if there is a lack of experience in superficial high-dose-rate brachytherapy techniques or with limited resources. We present a novel method of manufacturing superficial brachytherapy applicators utilizing three-dimensional (3D)-printing techniques. We describe the treatment planning process and the process of applicator manufacture. The treatment planning process, with the introduction of a pre-plan, allows for an "ideal" catheter arrangement within an applicator to be determined, exploiting varying catheter orientations, heights, and curvatures if required. The pre-plan arrangement is then 3D printed to the exact specifications of the pre-plan applicator design. This results in improved target volume coverage and improved sparing of organs at risk. Using a pre-plan technique for ideal catheter placement followed by automated 3D-printed applicator manufacture has greatly improved the entire process of superficial high-dose-rate brachytherapy treatment. We are able to design and manufacture flexible, well-fitting, superior quality applicators resulting in a more efficient and improved patient pathway and patient experience. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Outcomes and Control Rates for I-125 Plaque Brachytherapy for Uveal Melanoma: A Community-Based Institutional Experience

PubMed Central

Cook, Taylor

2014-01-01

Purpose. To evaluate our community-based institutional experience with plaque brachytherapy for uveal melanomas with a focus on local control rates, factors impacting disease progression, and dosimetric parameters impacting treatment toxicity. Methods and Materials. Our institution was retrospectively reviewed from 1996 to 2011; all patients who underwent plaque brachytherapy for uveal melanoma were included. Follow-up data were collected regarding local control, distant metastases, and side effects from treatment. Analysis was performed on factors impacting treatment outcomes and treatment toxicity. Results. A total of 107 patients underwent plaque brachytherapy, of which 88 had follow-up data available. Local control at 10 years was 94%. Freedom from progression (FFP) and overall survival at 10 years were 83% and 79%, respectively. On univariate analysis, there were no tumor or dosimetric treatment characteristics that were found to have a prognostic impact on FFP. Brachytherapy treatment was well tolerated, with clinically useful vision (>20/200) maintained in 64% of patients. Statistically significant dosimetric relationships were established with cataract, glaucoma, and retinopathy development (greatest P = 0.05). Conclusions. Treatment with plaque brachytherapy demonstrates excellent outcomes in a community-based setting. It is well tolerated and should remain a standard of care for COMS medium sized tumors. PMID:24734198

SU-F-T-58: Dosimetric Evaluation of Breast Tissue Composition for Electronic Brachytherapy (BET) Source In High Dose Rate Accelerated Partial Breast (APBI) Irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, W; Johnson, D; Ahmad, S

Purpose: To quantitatively evaluate the dosimetric impact of differing breast tissue compositions for electronic brachytherapy source for high dose rate accelerated partial breast irradiation. Methods: A series of Monte Carlo Simulation were created using the GEANT4 toolkit (version 10.0). The breast phantom was modeled as a semi-circle with a radius of 5.0 cm. A water balloon with a radius of 1.5 cm was located in the phantom with the Xoft AxxentTM EBT source placed at center as a point source. A mixed of two tissue types (adipose and glandular tissue) was assigned as the materials for the breast phantom withmore » different weight ratios. The proportionality of glandular and adipose tissue was simulated in four different fashions, 80/20, 70/30, 50/50 and 30/70 respectively. The custom energy spectrum for the 50 kVp XOFT source was provided via the manufacturer and used to generate incident photons. The dose distributions were recorded using a parallel three dimensional mesh with a size of 30 × 30 × 30 cm3 with 1 × 1 × 1 mm3 voxels. The simulated doses absorbed along the transverse axis were normalized at the distance of 1 cm and then compared with the calculations using standard TG-43 formalism. Results: All simulations showed underestimation of dose beyond balloon surface compared to standard TG-43 calculations. The maximum percentage differences within 2 cm distance from balloon surface were found to be 18%, 11%, 10% and 8% for the fat breast (30/70), standard breast (50/50), dense breast (70/30 and 80/20), respectively. Conclusion: The accuracy of dose calculations for low energy EBT source was limited when considering tissue heterogeneous composition. The impact of atomic number on photo-electric effect for lower energy Brachytherapy source is not accounted for and resulting in significant errors in dose calculation.« less

Developing a Treatment Planning Software Based on TG-43U1 Formalism for Cs-137 LDR Brachytherapy.

PubMed

Sina, Sedigheh; Faghihi, Reza; Soleimani Meigooni, Ali; Siavashpour, Zahra; Mosleh-Shirazi, Mohammad Amin

2013-08-01

The old Treatment Planning Systems (TPSs) used for intracavitary brachytherapy with Cs-137 Selectron source utilize traditional dose calculation methods, considering each source as a point source. Using such methods introduces significant errors in dose estimation. As of 1995, TG-43 is used as the main dose calculation formalism in treatment TPSs. The purpose of this study is to design and establish a treatment planning software for Cs-137 Solectron brachytherapy source, based on TG-43U1 formalism by applying the effects of the applicator and dummy spacers. Two softwares used for treatment planning of Cs-137 sources in Iran (STPS and PLATO), are based on old formalisms. The purpose of this work is to establish and develop a TPS for Selectron source based on TG-43 formalism. In this planning system, the dosimetry parameters of each pellet in different places inside applicators were obtained by MCNP4c code. Then the dose distribution around every combination of active and inactive pellets was obtained by summing the doses. The accuracy of this algorithm was checked by comparing its results for special combination of active and inactive pellets with MC simulations. Finally, the uncertainty of old dose calculation formalism was investigated by comparing the results of STPS and PLATO softwares with those obtained by the new algorithm. For a typical arrangement of 10 active pellets in the applicator, the percentage difference between doses obtained by the new algorithm at 1cm distance from the tip of the applicator and those obtained by old formalisms is about 30%, while the difference between the results of MCNP and the new algorithm is less than 5%. According to the results, the old dosimetry formalisms, overestimate the dose especially towards the applicator's tip. While the TG-43U1 based software perform the calculations more accurately.

SU-E-T-333: Towards Customizable Radiotherapy Enhancement (CuRE) for Prostate Cancer Using Cisplatin Nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinha, N; Cifter, G; Sajo, E

2014-06-01

Purpose: Replacing routinely used brachytherapy spacers with multifunctional ones loaded with cisplatin nanoparticles (CNP), which can be released into the tumor after implantation, could enable customizable radiation boosting to the prostate tumor in addition to chemotherapy effect. This study investigates the feasibility of customizing the intra-tumor biodistribution and corresponding dose enhancement (DEF) over time for the released CNP as a function of nanoparticle size. Methods: Dose enhancement factors (DEF) due to photon-induced emission of photo-/Auger electrons from CNPs were calculated as a function of concentration using previously published analytical calculation method. An experimentally determined diffusion coefficient (D) for 10 nmmore » nanoparticles in mouse tumor model was employed to estimate D for other sizes using the Stoke- Einstein equation. The error function diffusion model in the experimental study was applied to generate the intra-tumor concentration profile for a burst release of CNPs from the spacer over time. The corresponding DEF profiles were then determined for brachytherapy using Pd-103 and I-125 sources. Results: As expected, the generated profiles showed greater DEF over time for smaller CNP sizes at sample distances from the spacer. For example, for a centrally located spacer, clinically significant DEF (> 20%) could be achieved near the tumor periphery (ca. 0.85 cm distance from the spacer for average PCa tumor size) after 20, and 100 days, respectively for CNPs sizes of 2 nm, and 10 nm, using I-125. Meanwhile for Pd-103, clinically significant DEF could be achieved at the same position after 22 and 108 days, respectively, for same size particles. Conclusion: Our preliminary results demonstrate the feasibility of customizing dose enhancement to prostate tumors as a function of spacer location, brachytherapy source type or size of CNPs released from multifunctional spacers. Such an approach could enable customizable radiation boosting to tumor sub-volumes, while minimizing dose to healthy tissues.« less

Placement of empty catheters for an HDR-emulating LDR prostate brachytherapy technique: comparison to standard intraoperative planning.

PubMed

Niedermayr, Thomas R; Nguyen, Paul L; Murciano-Goroff, Yonina R; Kovtun, Konstantin A; Neubauer Sugar, Emily; Cail, Daniel W; O'Farrell, Desmond A; Hansen, Jorgen L; Cormack, Robert A; Buzurovic, Ivan; Wolfsberger, Luciant T; O'Leary, Michael P; Steele, Graeme S; Devlin, Philip M; Orio, Peter F

2014-01-01

We sought to determine whether placing empty catheters within the prostate and then inverse planning iodine-125 seed locations within those catheters (High Dose Rate-Emulating Low Dose Rate Prostate Brachytherapy [HELP] technique) would improve concordance between planned and achieved dosimetry compared with a standard intraoperative technique. We examined 30 consecutive low dose rate prostate cases performed by standard intraoperative technique of planning followed by needle placement/seed deposition and compared them to 30 consecutive low dose rate prostate cases performed by the HELP technique. The primary endpoint was concordance between planned percentage of the clinical target volume that receives at least 100% of the prescribed dose/dose that covers 90% of the volume of the clinical target volume (V100/D90) and the actual V100/D90 achieved at Postoperative Day 1. The HELP technique had superior concordance between the planned target dosimetry and what was actually achieved at Day 1 and Day 30. Specifically, target D90 at Day 1 was on average 33.7 Gy less than planned for the standard intraoperative technique but was only 10.5 Gy less than planned for the HELP technique (p < 0.001). Day 30 values were 16.6 Gy less vs. 2.2 Gy more than planned, respectively (p = 0.028). Day 1 target V100 was 6.3% less than planned with standard vs. 2.8% less for HELP (p < 0.001). There was no significant difference between the urethral and rectal concordance (all p > 0.05). Placing empty needles first and optimizing the plan to the known positions of the needles resulted in improved concordance between the planned and the achieved dosimetry to the target, possibly because of elimination of errors in needle placement. Copyright © 2014 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

SU-E-T-477: An Efficient Dose Correction Algorithm Accounting for Tissue Heterogeneities in LDR Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mashouf, S; Lai, P; Karotki, A

2014-06-01

Purpose: Seed brachytherapy is currently used for adjuvant radiotherapy of early stage prostate and breast cancer patients. The current standard for calculation of dose surrounding the brachytherapy seeds is based on American Association of Physicist in Medicine Task Group No. 43 (TG-43 formalism) which generates the dose in homogeneous water medium. Recently, AAPM Task Group No. 186 emphasized the importance of accounting for tissue heterogeneities. This can be done using Monte Carlo (MC) methods, but it requires knowing the source structure and tissue atomic composition accurately. In this work we describe an efficient analytical dose inhomogeneity correction algorithm implemented usingmore » MIM Symphony treatment planning platform to calculate dose distributions in heterogeneous media. Methods: An Inhomogeneity Correction Factor (ICF) is introduced as the ratio of absorbed dose in tissue to that in water medium. ICF is a function of tissue properties and independent of source structure. The ICF is extracted using CT images and the absorbed dose in tissue can then be calculated by multiplying the dose as calculated by the TG-43 formalism times ICF. To evaluate the methodology, we compared our results with Monte Carlo simulations as well as experiments in phantoms with known density and atomic compositions. Results: The dose distributions obtained through applying ICF to TG-43 protocol agreed very well with those of Monte Carlo simulations as well as experiments in all phantoms. In all cases, the mean relative error was reduced by at least 50% when ICF correction factor was applied to the TG-43 protocol. Conclusion: We have developed a new analytical dose calculation method which enables personalized dose calculations in heterogeneous media. The advantages over stochastic methods are computational efficiency and the ease of integration into clinical setting as detailed source structure and tissue segmentation are not needed. University of Toronto, Natural Sciences and Engineering Research Council of Canada.« less

Real-time intraoperative evaluation of implant quality and dose correction during prostate brachytherapy consistently improves target coverage using a novel image fusion and optimization program.

PubMed

Zelefsky, Michael J; Cohen, Gilad N; Taggar, Amandeep S; Kollmeier, Marisa; McBride, Sean; Mageras, Gig; Zaider, Marco

Our purpose was to describe the process and outcome of performing postimplantation dosimetric assessment and intraoperative dose correction during prostate brachytherapy using a novel image fusion-based treatment-planning program. Twenty-six consecutive patients underwent intraoperative real-time corrections of their dose distributions at the end of their permanent seed interstitial procedures. After intraoperatively planned seeds were implanted and while the patient remained in the lithotomy position, a cone beam computed tomography scan was obtained to assess adequacy of the prescription dose coverage. The implanted seed positions were automatically segmented from the cone-beam images, fused onto a new set of acquired ultrasound images, reimported into the planning system, and recontoured. Dose distributions were recalculated based upon actual implanted seed coordinates and recontoured ultrasound images and were reviewed. If any dose deficiencies within the prostate target were identified, additional needles and seeds were added. Once an implant was deemed acceptable, the procedure was completed, and anesthesia was reversed. When the intraoperative ultrasound-based quality assurance assessment was performed after seed placement, the median volume receiving 100% of the dose (V100) was 93% (range, 74% to 98%). Before seed correction, 23% (6/26) of cases were noted to have V100 <90%. Based on this intraoperative assessment and replanning, additional seeds were placed into dose-deficient regions within the target to improve target dose distributions. Postcorrection, the median V100 was 97% (range, 93% to 99%). Following intraoperative dose corrections, all implants achieved V100 >90%. In these patients, postimplantation evaluation during the actual prostate seed implant procedure was successfully applied to determine the need for additional seeds to correct dose deficiencies before anesthesia reversal. When applied, this approach should significantly reduce intraoperative errors and chances for suboptimal dose delivery during prostate brachytherapy. Copyright © 2017 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shinohara, Eric T., E-mail: Shinohara@xrt.upenn.ed; Guo Mengye; Mitra, Nandita

Purpose: To examine the role of brachytherapy in the treatment of cholangiocarcinomas in a relatively large group of patients. Methods and Materials: Using the Surveillance, Epidemiology and End Results database, a total of 193 patients with cholangiocarcinoma treated with brachytherapy were identified for the period 1988-2003. The primary analysis compared patients treated with brachytherapy (with or without external-beam radiation) with those who did not receive radiation. To try to account for confounding variables, propensity score and sensitivity analyses were used. Results: There was a significant difference between patients who received radiation (n = 193) and those who did not (nmore » = 6859) with regard to surgery (p < 0.0001), race (p < 0.0001), stage (p < 0.0001), and year of diagnosis (p <0.0001). Median survival for patients treated with brachytherapy was 11 months (95% confidence interval [CI] 9-13 months), compared with 4 months for patients who received no radiation (p < 0.0001). On multivariable analysis (hazard ratio [95% CI]) brachytherapy (0.79 [0.66-0.95]), surgery (0.50 [0.46-0.53]), year of diagnosis (1998-2003: 0.66 [0.60-0.73]; 1993-1997: (0.96 [0.89-1.03; NS], baseline 1988-1992), and extrahepatic disease (0.84 [0.79-0.89]) were associated with better overall survival. Conclusions: To the authors' knowledge, this is the largest dataset reported for the treatment of cholangiocarcinomas with brachytherapy. The results of this retrospective analysis suggest that brachytherapy may improve overall survival. However, because of the limitations of the Surveillance, Epidemiology and End Results database, these results should be interpreted cautiously, and future prospective studies are needed.« less

Brachytherapy for Buccal Cancer: From Conventional Low Dose Rate (LDR) or Mold Technique to High Dose Rate Interstitial Brachytherapy (HDR-ISBT).

PubMed

Kotsuma, Tadayuki; Yamazaki, Hideya; Masui, Koji; Yoshida, Ken; Shimizutani, Kimishige; Akiyama, Hironori; Murakami, Shumei; Isohashi, Fumiaki; Yoshioka, Yasuo; Ogawa, Kazuhiko; Tanaka, Eiichi

2017-12-01

To examine the effectiveness of newly-installed high-dose-rate interstitial brachytherapy (HDR-ISBT) for buccal cancer. We retrospectively reviewed 36 patients (25 men and 11 women) with buccal cancer treated with curative brachytherapy with or without external radiotherapy with a median follow-up of 99 months. A total of 15 HDR-ISBT (median 48 Gy/ 8 fractions, range=24-60 Gy) patients were compared to conventional 15 cases LDR-ISBT (70 Gy, range=42.8-110 Gy) and 7 molds techniques (15 Gy, range=9-74 Gy). A total of 31 patients also underwent external radiotherapy (30 Gy, range=24-48 Gy). They comprised of 3T1, 23 T2, 8 T3, 3 T4 including 11 node positive cases. HDR-ISBT provided 82% of local control rate at 5 years, whereas conventional brachytherapy showed 72% [p=0.44; LDR-ISBT (65%), mold therapy (85.7%)]. Patients with early lesions (T1-2 or stage I-II) showed better local control rates than those with advanced lesions (T3-4 or stage III-IV). Severe late grade 3 complications developed in two patients treated with LDR-ISBT and EBRT. There is no significant difference in toxicity grade ≤2 between conventional brachytherapy (5/15=33%) and HDR-ISBT (7/32=32%, p=0.92). HDR-ISBT achieved good and comparable local control rates to conventional brachytherapy without elevating the toxicity. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, Beant S.; Lin, Jeff F.; Krivak, Thomas C.

Purpose: To utilize the National Cancer Data Base to evaluate trends in brachytherapy and alternative radiation therapy utilization in the treatment of cervical cancer, to identify associations with outcomes between the various radiation therapy modalities. Methods and Materials: Patients with International Federation of Gynecology and Obstetrics stage IIB-IVA cervical cancer in the National Cancer Data Base who received treatment from January 2004 to December 2011 were analyzed. Overall survival was estimated by the Kaplan-Meier method. Univariate and multivariable analyses were performed to identify factors associated with type of boost radiation modality used and its impact on survival. Results: A totalmore » of 7654 patients had information regarding boost modality. A predominant proportion of patients were Caucasian (76.2%), had stage IIIB (48.9%) disease with squamous (82.0%) histology, were treated at academic/research centers (47.7%) in the South (34.8%), and lived 0 to 5 miles (27.9%) from the treating facility. A majority received brachytherapy (90.3%). From 2004 to 2011, brachytherapy use decreased from 96.7% to 86.1%, whereas intensity modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT) use increased from 3.3% to 13.9% in the same period (P<.01). Factors associated with decreased brachytherapy utilization included older age, stage IVA disease, smaller tumor size, later year of diagnosis, lower-volume treatment centers, and facility type. After controlling for significant factors from survival analyses, IMRT or SBRT boost resulted in inferior overall survival (hazard ratio, 1.86; 95% confidence interval, 1.35-2.55; P<.01) as compared with brachytherapy. In fact, the survival detriment associated with IMRT or SBRT boost was stronger than that associated with excluding chemotherapy (hazard ratio, 1.61′ 95% confidence interval, 1.27-2.04′ P<.01). Conclusions: Consolidation brachytherapy is a critical treatment component for locally advanced cervical cancer; however, there has been declining utilization of brachytherapy. Increased use of IMRT and SBRT boost coupled with increased mortality risk should raise concerns about utilizing these approaches over brachytherapy.« less

Rectal bleeding after high-dose-rate brachytherapy combined with hypofractionated external-beam radiotherapy for localized prostate cancer: Impact of rectal dose in high-dose-rate brachytherapy on occurrence of grade 2 or worse rectal bleeding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akimoto, Tetsuo; Katoh, Hiroyuki; Kitamoto, Yoshizumi

2006-06-01

Purpose: To evaluate the incidence of Grade 2 or worse rectal bleeding after high-dose-rate (HDR) brachytherapy combined with hypofractionated external-beam radiotherapy (EBRT), with special emphasis on the relationship between the incidence of rectal bleeding and the rectal dose from HDR brachytherapy. Methods and Materials: The records of 100 patients who were treated by HDR brachytherapy combined with EBRT for {>=}12 months were analyzed. The fractionation schema for HDR brachytherapy was prospectively changed, and the total radiation dose for EBRT was fixed at 51 Gy. The distribution of the fractionation schema used in the patients was as follows: 5 Gy xmore » 5 in 13 patients; 7 Gy x 3 in 19 patients; and 9 Gy x 2 in 68 patients. Results: Ten patients (10%) developed Grade 2 or worse rectal bleeding. Regarding the correlation with dosimetric factors, no significant differences were found in the average percentage of the entire rectal volume receiving 30%, 50%, 80%, and 90% of the prescribed radiation dose from EBRT between those with bleeding and those without. The average percentage of the entire rectal volume receiving 10%, 30%, 50%, 80%, and 90% of the prescribed radiation dose from HDR brachytherapy in those who developed rectal bleeding was 77.9%, 28.6%, 9.0%, 1.5%, and 0.3%, respectively, and was 69.2%, 22.2%, 6.6%, 0.9%, and 0.4%, respectively, in those without bleeding. The differences in the percentages of the entire rectal volume receiving 10%, 30%, and 50% between those with and without bleeding were statistically significant. Conclusions: The rectal dose from HDR brachytherapy for patients with prostate cancer may have a significant impact on the incidence of Grade 2 or worse rectal bleeding.« less

Vaginal cuff dehiscence after intracavitary brachytherapy for endometrial cancer

PubMed Central

Shah, Karan; Potkul, Ronald

2012-01-01

We describe 2 unusual cases of vaginal dehiscence after intracavitary brachytherapy performed following robotic laparoscopic hysterectomy (RLH) along with their management. This unusual complication, which may be more common because of the robotic procedures, can be prevented by careful examination and possible delay of the onset of brachytherapy, if indicated. Our report reviews techniques of avoiding this complication and suggests that these complications should be discussed with the patients. PMID:23349653

Whitmore, Henschke, and Hilaris: The reorientation of prostate brachytherapy (1970-1987).

PubMed

Aronowitz, Jesse N

2012-01-01

Urologists had performed prostate brachytherapy for decades before New York's Memorial Hospital retropubic program. This paper explores the contribution of Willet Whitmore, Ulrich Henschke, Basil Hilaris, and Memorial's physicists to the evolution of the procedure. Literature review and interviews with program participants. More than 1000 retropubic implants were performed at Memorial between 1970 and 1987. Unlike previous efforts, Memorial's program benefited from the participation of three disciplines in its conception and execution. Memorial's retropubic program was a collaboration of urologists, radiation therapists, and physicists. Their approach focused greater attention on dosimetry and radiation safety, and served as a template for subsequent prostate brachytherapy programs. Copyright © 2012 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Grace L.; Department of Health Services Research, The University of Texas MD Anderson Cancer Center, Houston, Texas; Huo, Jinhai

Purpose: To directly compare (1) radiation treatment utilization patterns; (2) risks of subsequent mastectomy; and (3) costs of radiation treatment in patients treated with brachytherapy versus whole-breast irradiation (WBI), in a national, contemporary cohort of women with incident breast cancer, aged 64 years and younger. Methods and Materials: Using MarketScan health care claims data, we identified 45,884 invasive breast cancer patients (aged 18-64 years), treated from 2003 to 2010 with lumpectomy, followed by brachytherapy (n=3134) or whole-breast irradiation (n=42,750). We stratified patients into risk groups according to age (Age<50 vs Age≥50) and endocrine therapy status (Endocrine− vs Endocrine+). “Endocrine+” patients filled an endocrinemore » therapy prescription within 1 year after lumpectomy. Pathologic hormone receptor status was not available in this dataset. In brachytherapy versus WBI patients, utilization trends and 5-year subsequent mastectomy risks were compared. Stratified, adjusted subsequent mastectomy risks were calculated using proportional hazards regression. Results: Brachytherapy utilization increased from 2003 to 2010: in patients Age<50, from 0.6% to 4.9%; patients Age≥50 from 2.2% to 11.3%; Endocrine− patients, 1.3% to 9.4%; Endocrine+ patients, 1.9% to 9.7%. Age influenced treatment selection more than endocrine status: 17% of brachytherapy patients were Age<50 versus 32% of WBI patients (P<.001); whereas 41% of brachytherapy patients were Endocrine–versus 44% of WBI patients (P=.003). Highest absolute 5-year subsequent mastectomy risks occurred in Endocrine−/Age<50 patients (24.4% after brachytherapy vs 9.0% after WBI (hazard ratio [HR] 2.18, 95% confidence interval [CI] 1.37-3.47); intermediate risks in Endocrine−/Age≥50 patients (8.6% vs 4.9%; HR 1.76, 95% CI 1.26-2.46); and lowest risks in Endocrine+ patients of any age: Endocrine+/Age<50 (5.5% vs 4.5%; HR 1.18, 95% CI 0.61-2.31); Endocrine+/Age≥50 (4.2% vs 2.4%; HR 1.71, 95% CI 1.16-2.51). Conclusion: In this younger cohort, endocrine status was a valuable discriminatory factor predicting subsequent mastectomy risk after brachytherapy versus WBI and therefore may be useful for selecting appropriate younger brachytherapy candidates.« less

Determination of the intrinsic energy dependence of LiF:Mg,Ti thermoluminescent dosimeters for 125I and 103Pd brachytherapy sources relative to 60Co.

PubMed

Reed, J L; Rasmussen, B E; Davis, S D; Micka, J A; Culberson, W S; DeWerd, L A

2014-12-01

To determine the intrinsic energy dependence of LiF:Mg,Ti thermoluminescent dosimeters (TLD-100) for (125)I and (103)Pd brachytherapy sources relative to (60)Co. LiF:Mg,Ti TLDs were irradiated with low-energy brachytherapy sources and with a (60)Co teletherapy source. The brachytherapy sources measured were the Best 2301 (125)I seed, the OncoSeed 6711 (125)I seed, and the Best 2335 (103)Pd seed. The TLD light output per measured air-kerma strength was determined for the brachytherapy source irradiations, and the TLD light output per air kerma was determined for the (60)Co irradiations. Monte Carlo (MC) simulations were used to calculate the dose-to-TLD rate per air-kerma strength for the brachytherapy source irradiations and the dose to TLD per air kerma for the (60)Co irradiations. The measured and MC-calculated results for all irradiations were used to determine the TLD intrinsic energy dependence for (125)I and (103)Pd relative to (60)Co. The relative TLD intrinsic energy dependences (relative to (60)Co) and associated uncertainties (k = 1) were determined to be 0.883 ± 1.3%, 0.870 ± 1.4%, and 0.871 ± 1.5% for the Best 2301 seed, OncoSeed 6711 seed, and Best 2335 seed, respectively. The intrinsic energy dependence of TLD-100 is dependent on photon energy, exhibiting changes of 13%-15% for (125)I and (103)Pd sources relative to (60)Co. TLD measurements of absolute dose around (125)I and (103)Pd brachytherapy sources should explicitly account for the relative TLD intrinsic energy dependence in order to improve dosimetric accuracy.

The Royal College of Radiologists' audit of prostate brachytherapy in the year 2012.

PubMed

Stewart, A J; Drinkwater, K J; Laing, R W; Nobes, J P; Locke, I

2015-06-01

This audit provides a comprehensive overview of UK prostate brachytherapy practice in the year 2012, measured against existing standards, immediately before the introduction of new Royal College of Radiologists (RCR) guidelines. This audit allows comparison with European and North American brachytherapy practice and for the impact of the RCR 2012 guidelines to be assessed in the future. A web-based data collection tool was developed by the RCR Clinical Audit Committee and sent to audit leads at all cancer centres in the UK. Standards were developed based on available guidelines in use at the start of 2012 covering case mix and dosimetry. Further questions were included to reflect areas of anticipated change with the implementation of the 2012 guidelines. Audit findings were compared with similar audits of practice in Europe, the USA and Latin America. Forty-nine of 59 cancer centres submitted data. Twenty-nine centres reported carrying out prostate brachytherapy; of these, 25 (86%) provided data regarding the number of implants, staffing, dosimetry, medication and anaesthesia and follow-up. Audit standards achieved excellent compliance in most areas, although were low in post-implant dosimetry and in post-implant scanning at 30 days. This audit provides a comprehensive picture of prostate brachytherapy in the UK in 2012. Patterns of care of prostate brachytherapy are similar to practice in the USA and Europe. The number of prostate brachytherapy implants carried out in the UK has grown significantly since a previous RCR audit in 2005 and it is important that centres maintain minimum numbers of cases to ensure that experience can be maintained and compliance to guidelines achieved. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Radioactive seed migration following parotid gland interstitial brachytherapy.

PubMed

Fan, Yi; Huang, Ming-Wei; Zhao, Yi-Jiao; Gao, Hong; Zhang, Jian-Guo

To evaluate the incidence and associated factors of pulmonary seed migration after parotid brachytherapy using a novel migrated seed detection technique. Patients diagnosed with parotid cancer who underwent permanent parotid brachytherapy from January 2006 to December 2011 were reviewed retrospectively. Head and neck CT scans and chest X-rays were evaluated during routine follow-up. Mimics software and Geomagic Studio software were used for seed reconstruction and migrated seed detection from the original implanted region, respectively. Postimplant dosimetry analysis was performed after seeds migration if the seeds were still in their emitting count. Adverse clinical sequelae from seed embolization to the lung were documented. The radioactive seed implants were identified on chest X-rays in 6 patients. The incidence rate of seed migration in 321 parotid brachytherapy patients was 1.87% (6/321) and that of individual seed migration was 0.04% (6/15218 seeds). All migrated seeds were originally from the retromandibular region. No adverse dosimetric consequences were found in the target region. Pulmonary symptoms were not reported by any patient in this study. In our patient set, migration of radioactive seeds with an initial radioactivity of 0.6-0.7 mCi to the chest following parotid brachytherapy was rare. Late migration of a single seed from the central target region did not affect the dosimetry significantly, and patients did not have severe short-term complications. This study proposed a novel technique to localize the anatomical origin of the migrated seeds during brachytherapy. Our evidence suggested that placement of seeds adjacent to blood vessels was associated with an increased likelihood of seed migration to the lungs. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Australian patterns of prostate cancer care: Are they evolving?

PubMed Central

Lo, Jonathon; Papa, Nathan; Bolton, Damien M.; Murphy, Declan; Lawrentschuk, Nathan

2015-01-01

Background Approaches to prostate cancer (PCa) care have changed in recent years out of concern for overdiagnosis and overtreatment. Despite these changes, many patients continue to undergo some form of curative treatment and with a growing perception among multidisciplinary clinicians that more aggressive treatments are being favored. This study examines patterns of PCa care in Australia, focusing on current rates of screening and aggressive interventions that consist of high-dose-rate (HDR) brachytherapy and pelvic lymph node dissection (PLND). Methods Health services data were used to assess Australian men undergoing PCa screening and treatment from 2001 to 2014. Age-specific rates of prostate-specific antigen (PSA) screening were calculated. Ratios of radical prostatectomy (RP) with PLND to RP without PLND, and HDR brachytherapy to low-dose-rate (LDR) brachytherapy were determined by state jurisdictions. Results From 2008, the rate of PSA screening trended downward significantly with year for all age ranges (P < 0.02) except men aged ≥ 85 (P = 0.56). PLND rates for 2008–2014 were lower than rates for 2001–2007 across all states and territories. From 2008 to 2014, PLND was performed ≥ 2.7 times more frequently in New South Wales and the Australian Capital Territory than in other jurisdictions. Since 2007, brachytherapy practice across Australia has evolved towards a relatively low use of HDR brachytherapy (ratio of HDR to LDR brachytherapy < 0.5 for all jurisdictions except the Australian Capital Territory). Conclusion Rates of PLND and HDR brachytherapy for PCa have declined in Australia, providing evidence for the effect of stage migration due to widespread PSA screening. Currently, PSA screening rates remain high among older men, which may expose them to unnecessary investigations and treatment-related morbidity. PMID:27014660

Health-Related Quality of Life up to Six Years After {sup 125}I Brachytherapy for Early-Stage Prostate Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roeloffzen, Ellen M.A., E-mail: E.M.A.Roeloffzen@UMCUtrecht.n; Lips, Irene M.; Gellekom, Marion P.R. van

2010-03-15

Purpose: Health-related quality of life (HRQOL) after prostate brachytherapy has been extensively described in published reports but hardly any long-term data are available. The aim of the present study was to prospectively assess long-term HRQOL 6 years after {sup 125}I prostate brachytherapy. Methods and Materials: A total of 127 patients treated with {sup 125}I brachytherapy for early-stage prostate cancer between December 2000 and June 2003 completed a HRQOL questionnaire at five time-points: before treatment and 1 month, 6 months, 1 year, and 6 years after treatment. The questionnaire included the RAND-36 generic health survey, the cancer-specific European Organization for Researchmore » and Treatment of Cancer core questionnaire (EORTCQLQ-C30), and the tumor-specific EORTC prostate cancer module (EORTC-PR25). A change in a score of >=10 points was considered clinically relevant. Results: Overall, the HRQOL at 6 years after {sup 125}I prostate brachytherapy did not significantly differ from baseline. Although a statistically significant deterioration in HRQOL at 6 years was seen for urinary symptoms, bowel symptoms, pain, physical functioning, and sexual activity (p <.01), most changes were not clinically relevant. A statistically significant improvement at 6 years was seen for mental health, emotional functioning, and insomnia (p <.01). The only clinically relevant changes were seen for emotional functioning and sexual activity. Conclusion: This is the first study presenting prospective HRQOL data up to 6 years after {sup 125}I prostate brachytherapy. HRQOL scores returned to approximately baseline values at 1 year and remained stable up to 6 years after treatment. {sup 125}I prostate brachytherapy did not adversely affect patients' long-term HRQOL.« less

MO-FG-210-00: US Guided Systems for Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Ultrasound (US) is one of the most widely used imaging modalities in medical practice. Since US imaging offers real-time imaging capability, it has becomes an excellent option to provide image guidance for brachytherapy (IGBT). (1) The physics and the fundamental principles of US imaging are presented, and the typical steps required to commission an US system for IGBT is provided for illustration. (2) Application of US for prostate HDR brachytherapy, including partial prostate treatments using MR-ultrasound co-registration to enable a focused treatment on the disease within the prostate is also presented. Prostate HDR with US image guidance planning can benefitmore » from real time visualization of the needles, and fusion of the ultrasound images with T2 weighted MR allows the focusing of the treatment to the specific areas of disease within the prostate, so that the entire gland need not be treated. Finally, (3) ultrasound guidance for an eye plaque program is presented. US can be a key component of placement and QA for episcleral plaque brachytherapy for ocular cancer, and the UCLA eye plaque program with US for image guidance is presented to demonstrate the utility of US verification of plaque placement in improving the methods and QA in episcleral plaque brachytherapy. Learning Objectives: To understand the physics of an US system and the necessary aspects of commissioning US for image guided brachytherapy (IGBT). To understand real time planning of prostate HDR using ultrasound, and its application in partial prostate treatments using MR-ultrasound fusion to focus treatment on disease within the prostate. To understand the methods and QA in applying US for localizing the target and the implant during a episcleral plaque brachytherapy procedures.« less

MO-FG-210-01: Commissioning An US System for Brachytherapy: An Overview of Physics, Instrumentation, and Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Z.

Ultrasound (US) is one of the most widely used imaging modalities in medical practice. Since US imaging offers real-time imaging capability, it has becomes an excellent option to provide image guidance for brachytherapy (IGBT). (1) The physics and the fundamental principles of US imaging are presented, and the typical steps required to commission an US system for IGBT is provided for illustration. (2) Application of US for prostate HDR brachytherapy, including partial prostate treatments using MR-ultrasound co-registration to enable a focused treatment on the disease within the prostate is also presented. Prostate HDR with US image guidance planning can benefitmore » from real time visualization of the needles, and fusion of the ultrasound images with T2 weighted MR allows the focusing of the treatment to the specific areas of disease within the prostate, so that the entire gland need not be treated. Finally, (3) ultrasound guidance for an eye plaque program is presented. US can be a key component of placement and QA for episcleral plaque brachytherapy for ocular cancer, and the UCLA eye plaque program with US for image guidance is presented to demonstrate the utility of US verification of plaque placement in improving the methods and QA in episcleral plaque brachytherapy. Learning Objectives: To understand the physics of an US system and the necessary aspects of commissioning US for image guided brachytherapy (IGBT). To understand real time planning of prostate HDR using ultrasound, and its application in partial prostate treatments using MR-ultrasound fusion to focus treatment on disease within the prostate. To understand the methods and QA in applying US for localizing the target and the implant during a episcleral plaque brachytherapy procedures.« less

MO-FG-210-02: Implementation of Image-Guided Prostate HDR Brachytherapy Using MR-Ultrasound Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, B.

Ultrasound (US) is one of the most widely used imaging modalities in medical practice. Since US imaging offers real-time imaging capability, it has becomes an excellent option to provide image guidance for brachytherapy (IGBT). (1) The physics and the fundamental principles of US imaging are presented, and the typical steps required to commission an US system for IGBT is provided for illustration. (2) Application of US for prostate HDR brachytherapy, including partial prostate treatments using MR-ultrasound co-registration to enable a focused treatment on the disease within the prostate is also presented. Prostate HDR with US image guidance planning can benefitmore » from real time visualization of the needles, and fusion of the ultrasound images with T2 weighted MR allows the focusing of the treatment to the specific areas of disease within the prostate, so that the entire gland need not be treated. Finally, (3) ultrasound guidance for an eye plaque program is presented. US can be a key component of placement and QA for episcleral plaque brachytherapy for ocular cancer, and the UCLA eye plaque program with US for image guidance is presented to demonstrate the utility of US verification of plaque placement in improving the methods and QA in episcleral plaque brachytherapy. Learning Objectives: To understand the physics of an US system and the necessary aspects of commissioning US for image guided brachytherapy (IGBT). To understand real time planning of prostate HDR using ultrasound, and its application in partial prostate treatments using MR-ultrasound fusion to focus treatment on disease within the prostate. To understand the methods and QA in applying US for localizing the target and the implant during a episcleral plaque brachytherapy procedures.« less

MO-FG-210-03: Intraoperative Ultrasonography-Guided Positioning of Plaque Brachytherapy in the Treatment of Choroidal Melanoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lamb, J.

2015-06-15

Ultrasound (US) is one of the most widely used imaging modalities in medical practice. Since US imaging offers real-time imaging capability, it has becomes an excellent option to provide image guidance for brachytherapy (IGBT). (1) The physics and the fundamental principles of US imaging are presented, and the typical steps required to commission an US system for IGBT is provided for illustration. (2) Application of US for prostate HDR brachytherapy, including partial prostate treatments using MR-ultrasound co-registration to enable a focused treatment on the disease within the prostate is also presented. Prostate HDR with US image guidance planning can benefitmore » from real time visualization of the needles, and fusion of the ultrasound images with T2 weighted MR allows the focusing of the treatment to the specific areas of disease within the prostate, so that the entire gland need not be treated. Finally, (3) ultrasound guidance for an eye plaque program is presented. US can be a key component of placement and QA for episcleral plaque brachytherapy for ocular cancer, and the UCLA eye plaque program with US for image guidance is presented to demonstrate the utility of US verification of plaque placement in improving the methods and QA in episcleral plaque brachytherapy. Learning Objectives: To understand the physics of an US system and the necessary aspects of commissioning US for image guided brachytherapy (IGBT). To understand real time planning of prostate HDR using ultrasound, and its application in partial prostate treatments using MR-ultrasound fusion to focus treatment on disease within the prostate. To understand the methods and QA in applying US for localizing the target and the implant during a episcleral plaque brachytherapy procedures.« less

Highly efficient method for production of radioactive silver seed cores for brachytherapy.

PubMed

Cardoso, Roberta Mansini; de Souza, Carla Daruich; Rostelato, Maria Elisa Chuery Martins; Araki, Koiti

2017-02-01

A simple and highly efficient (shorter reaction time and almost no rework) method for production of iodine based radioactive silver seed cores for brachytherapy is described. The method allows almost quantitative deposition of iodine-131 on dozens of silver substrates at once, with even distribution of activity per core and insignificant amounts of liquid and solid radioactive wastes, allowing the fabrication of cheaper radioactive iodine seeds for brachytherapy. Copyright © 2016. Published by Elsevier Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zoberi, J.

Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR ismore » U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.« less

Vibro-acoustography with 1.75D ultrasound array transducer for detection and localization of permanent prostate brachytherapy seeds: ex vivo study

NASA Astrophysics Data System (ADS)

Mehrmohammadi, Mohammad; Alizad, Azra; Kinnick, Randall R.; Davis, Brian J.; Fatemi, Mostafa

2013-03-01

Effective brachytherapy procedures require precise placement of radioactive seeds in the prostate. Currently, transrectal ultrasound (TRUS) imaging is one of the main intraoperative imaging modalities to assist physicians in placement of brachytherapy seeds. However, the seed detection rate with TRUS is poor mainly because ultrasound imaging is highly sensitive to variations in seed orientation. The purpose of this study is to investigate the abilities of a new acoustic radiation force imaging modality, vibro-acoustography (VA), equipped with a 1.75D array transducer and implemented on a customized clinical ultrasound scanner, to image and localize brachytherapy seeds in prostatic tissue. To perform experiments, excised cadaver prostate specimens were implanted with dummy brachytherapy seeds, and embedded in tissue mimicking gel to simulate the properties of the surrounding soft tissues. The samples were scanned using the VA system and the resulting VA signals were used to reconstruct VA images at several depths inside the tissue. To further evaluate the performance of VA in detecting seeds, X-ray computed tomography (CT) images of the same tissue sample, were obtained and used as a gold-standard to compare the number of seeds detected by the two methods. Our results indicate that VA is capable of imaging of brachytherapy seeds with accuracy and high contrast, and can detect a large percentage of the seeds implanted within the tissue samples.

Brachytherapy

MedlinePlus

... care for brachytherapy catheters. top of page What equipment is used? For permanent implants, radioactive material (which ... the tumor. top of page Who operates the equipment? The equipment is operated by a medical physicist, ...

Current situation of high-dose-rate brachytherapy for cervical cancer in Brazil*

PubMed Central

da Silva, Rogério Matias Vidal; Pinezi, Juliana Castro Dourado; Macedo, Luiz Eduardo Andrade; Souza, Divanízia do Nascimento

2014-01-01

Objective To assess the current situation of high-dose-rate (HDR) brachytherapy for cancer of the cervix in Brazil, regarding apparatuses, planning methods, prescription, fractionation schedule and evaluation of dose in organs at risk. Materials and Methods In the period between March/2012 and May/2013, a multiple choice questionnaire was developed and sent to 89 Brazilian hospitals which perform HDR brachytherapy. Results Sixty-one services answered the questionnaire. All regions of the country experienced a sharp increase in the number of HDR brachytherapy services in the period from 2001 to 2013. As regards planning, although a three-dimensional planning software was available in 91% of the centers, conventional radiography was mentioned by 92% of the respondents as their routine imaging method for such a purpose. Approximately 35% of respondents said that brachytherapy sessions are performed after teletherapy. The scheme of four 7 Gy intracavitary insertions was mentioned as the most frequently practiced. Conclusion The authors observed that professionals have difficulty accessing adjuvant three-dimensional planning tools such as computed tomography and magnetic resonance imaging. PMID:25741073

Adverse Events Involving Radiation Oncology Medical Devices: Comprehensive Analysis of US Food and Drug Administration Data, 1991 to 2015

DOE Office of Scientific and Technical Information (OSTI.GOV)

Connor, Michael J.; Department of Radiation Oncology, University of California Irvine School of Medicine, Irvine, California; Marshall, Deborah C.

Purpose: Radiation oncology relies on rapidly evolving technology and highly complex processes. The US Food and Drug Administration collects reports of adverse events related to medical devices. We sought to characterize all events involving radiation oncology devices (RODs) from the US Food and Drug Administration's postmarket surveillance Manufacturer and User Facility Device Experience (MAUDE) database, comparing these with non–radiation oncology devices. Methods and Materials: MAUDE data on RODs from 1991 to 2015 were sorted into 4 product categories (external beam, brachytherapy, planning systems, and simulation systems) and 5 device problem categories (software, mechanical, electrical, user error, and dose delivery impact).more » Outcomes included whether the device was evaluated by the manufacturer, adverse event type, remedial action, problem code, device age, and time since 510(k) approval. Descriptive statistics were performed with linear regression of time-series data. Results for RODs were compared with those for other devices by the Pearson χ{sup 2} test for categorical data and 2-sample Kolmogorov-Smirnov test for distributions. Results: There were 4234 ROD and 4,985,698 other device adverse event reports. Adverse event reports increased over time, and events involving RODs peaked in 2011. Most ROD reports involved external beam therapy (50.8%), followed by brachytherapy (24.9%) and treatment planning systems (21.6%). The top problem types were software (30.4%), mechanical (20.9%), and user error (20.4%). RODs differed significantly from other devices in each outcome (P<.001). RODs were more likely to be evaluated by the manufacturer after an event (46.9% vs 33.0%) but less likely to be recalled (10.5% vs 37.9%) (P<.001). Device age and time since 510(k) approval were shorter among RODs (P<.001). Conclusions: Compared with other devices, RODs may experience adverse events sooner after manufacture and market approval. Close postmarket surveillance, improved software design, and manufacturer–user training may help mitigate these events.« less

Seed Placement in Permanent Breast Seed Implant Brachytherapy: Are Concerns Over Accuracy Valid?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morton, Daniel, E-mail: dmorton@bccancer.bc.ca; Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia; Hilts, Michelle

Purpose: To evaluate seed placement accuracy in permanent breast seed implant brachytherapy (PBSI), to identify any systematic errors and evaluate their effect on dosimetry. Methods and Materials: Treatment plans and postimplant computed tomography scans for 20 PBSI patients were spatially registered and used to evaluate differences between planned and implanted seed positions, termed seed displacements. For each patient, the mean total and directional seed displacements were determined in both standard room coordinates and in needle coordinates relative to needle insertion angle. Seeds were labeled according to their proximity to the anatomy within the breast, to evaluate the influence of anatomicmore » regions on seed placement. Dosimetry within an evaluative target volume (seroma + 5 mm), skin, breast, and ribs was evaluated to determine the impact of seed placement on the treatment. Results: The overall mean (±SD) difference between implanted and planned positions was 9 ± 5 mm for the aggregate seed population. No significant systematic directional displacements were observed for this whole population. However, for individual patients, systematic displacements were observed, implying that intrapatient offsets occur during the procedure. Mean displacements for seeds in the different anatomic areas were not found to be significantly different from the mean for the entire seed population. However, small directional trends were observed within the anatomy, potentially indicating some bias in the delivery. Despite observed differences between the planned and implanted seed positions, the median (range) V{sub 90} for the 20 patients was 97% (66%-100%), and acceptable dosimetry was achieved for critical structures. Conclusions: No significant trends or systematic errors were observed in the placement of seeds in PBSI, including seeds implanted directly into the seroma. Recorded seed displacements may be related to intrapatient setup adjustments. Despite observed seed displacements, acceptable postimplant dosimetry was achieved.« less

Report to Congress on abnormal occurrences, October--December 1994. Volume 17, No. 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Section 208 of the Energy Reorganization Act of 1974 identifies an abnormal occurrence (AO) as an unscheduled incident or event that the Nuclear Regulatory Commission determines to be significant from the standpoint of public health or safety and requires a quarterly report of such occurrences to be made to Congress. This report provides a description of those incidents and events that have been determined to be AOs during the period of October 1 through December 31, 1994. This report addresses four AOs at NRC-licensed facilities. These occurrences involved the following: a generic concern relating to core shroud cracking in boilingmore » water reactors; recurring incidents of administering higher doses than procedurally allowed for diagnostic imaging at a single facility; one medical teletherapy misadministration; and one medical brachytherapy misadministration. Agreement States submitted four AO reports. These four occurrences involved the following: one major contamination at a commercial facility; two medical brachytherapy misadministrations; and one medical teletherapy misadministration. The report also contains updates of seven AOs previously reported by NRC licensees and four AOs previously reported by the Agreement States. Two ``Other Events of Interest`` are also being reported. These occurrences involved the operability of safety relief valves at a nuclear power plant, and an error in the installation process of a Leksell Gamma KnifeR teletherapy unit that resulted in an operational failure.« less

Cost and resource utilization in cervical cancer management: a real-world retrospective cost analysis.

PubMed

Cromwell, I; Ferreira, Z; Smith, L; van der Hoek, K; Ogilvie, G; Coldman, A; Peacock, S J

2016-02-01

We set out to assess the health care resource utilization and cost of cervical cancer from the perspective of a single-payer health care system. Retrospective observational data for women diagnosed with cervical cancer in British Columbia between 2004 and 2009 were analyzed to calculate patient-level resource utilization patterns from diagnosis to death or 5-year discharge. Domains of resource use within the scope of this cost analysis were chemotherapy, radiotherapy, and brachytherapy administered by the BC Cancer Agency; resource utilization related to hospitalization and outpatient visits as recorded by the B.C. Ministry of Health; medically required services billed under the B.C. Medical Services Plan; and prescriptions dispensed under British Columbia's health insurance programs. Unit costs were applied to radiotherapy and brachytherapy, producing per-patient costs. The mean cost per case of treating cervical cancer in British Columbia was $19,153 (standard error: $3,484). Inpatient hospitalizations, at 35%, represented the largest proportion of the total cost (95% confidence interval: 32.9% to 36.9%). Costs were compared for subgroups of the total cohort. As health care systems change the way they manage, screen for, and prevent cervical cancer, cost-effectiveness evaluations of the overall approach will require up-to-date data for resource utilization and costs. We provide information suitable for such a purpose and also identify factors that influence costs.

Estimating needle tip deflection in biological tissue from a single transverse ultrasound image: application to brachytherapy.

PubMed

Rossa, Carlos; Sloboda, Ron; Usmani, Nawaid; Tavakoli, Mahdi

2016-07-01

This paper proposes a method to predict the deflection of a flexible needle inserted into soft tissue based on the observation of deflection at a single point along the needle shaft. We model the needle-tissue as a discretized structure composed of several virtual, weightless, rigid links connected by virtual helical springs whose stiffness coefficient is found using a pattern search algorithm that only requires the force applied at the needle tip during insertion and the needle deflection measured at an arbitrary insertion depth. Needle tip deflections can then be predicted for different insertion depths. Verification of the proposed method in synthetic and biological tissue shows a deflection estimation error of [Formula: see text]2 mm for images acquired at 35 % or more of the maximum insertion depth, and decreases to 1 mm for images acquired closer to the final insertion depth. We also demonstrate the utility of the model for prostate brachytherapy, where in vivo needle deflection measurements obtained during early stages of insertion are used to predict the needle deflection further along the insertion process. The method can predict needle deflection based on the observation of deflection at a single point. The ultrasound probe can be maintained at the same position during insertion of the needle, which avoids complications of tissue deformation caused by the motion of the ultrasound probe.

Water equivalency evaluation of PRESAGE® dosimeters for dosimetry of Cs-137 and Ir-192 brachytherapy sources

NASA Astrophysics Data System (ADS)

Gorjiara, Tina; Hill, Robin; Kuncic, Zdenka; Baldock, Clive

2010-11-01

A major challenge in brachytherapy dosimetry is the measurement of steep dose gradients. This can be achieved with a high spatial resolution three dimensional (3D) dosimeter. PRESAGE® is a polyurethane based dosimeter which is suitable for 3D dosimetry. Since an ideal dosimeter is radiologically water equivalent, we have investigated the relative dose response of three different PRESAGE® formulations, two with a lower chloride and bromide content than original one, for Cs-137 and Ir-192 brachytherapy sources. Doses were calculated using the EGSnrc Monte Carlo package. Our results indicate that PRESAGE® dosimeters are suitable for relative dose measurement of Cs-137 and Ir-192 brachytherapy sources and the lower halogen content PRESAGE® dosimeters are more water equivalent than the original formulation.

Controlling the error on target motion through real-time mesh adaptation: Applications to deep brain stimulation.

PubMed

Bui, Huu Phuoc; Tomar, Satyendra; Courtecuisse, Hadrien; Audette, Michel; Cotin, Stéphane; Bordas, Stéphane P A

2018-05-01

An error-controlled mesh refinement procedure for needle insertion simulations is presented. As an example, the procedure is applied for simulations of electrode implantation for deep brain stimulation. We take into account the brain shift phenomena occurring when a craniotomy is performed. We observe that the error in the computation of the displacement and stress fields is localised around the needle tip and the needle shaft during needle insertion simulation. By suitably and adaptively refining the mesh in this region, our approach enables to control, and thus to reduce, the error whilst maintaining a coarser mesh in other parts of the domain. Through academic and practical examples we demonstrate that our adaptive approach, as compared with a uniform coarse mesh, increases the accuracy of the displacement and stress fields around the needle shaft and, while for a given accuracy, saves computational time with respect to a uniform finer mesh. This facilitates real-time simulations. The proposed methodology has direct implications in increasing the accuracy, and controlling the computational expense of the simulation of percutaneous procedures such as biopsy, brachytherapy, regional anaesthesia, or cryotherapy. Moreover, the proposed approach can be helpful in the development of robotic surgeries because the simulation taking place in the control loop of a robot needs to be accurate, and to occur in real time. Copyright © 2018 John Wiley & Sons, Ltd.

CT-image-based conformal brachytherapy of breast cancer. The significance of semi-3-D and 3-D treatment planning.

PubMed

Polgár, C; Major, T; Somogyi, A; Takácsi-Nagy, Z; Mangel, L C; Forrai, G; Sulyok, Z; Fodor, J; Németh, G

2000-03-01

To compare the conventional 2-D, the simulator-guided semi-3-D and the recently developed CT-guided 3-D brachytherapy treatment planning in the interstitial radiotherapy of breast cancer. In 103 patients with T1-2, N0-1 breast cancer the tumor bed was clipped during breast conserving surgery. Fifty-two of them received boost brachytherapy after 46 to 50 Gy teletherapy and 51 patients were treated with brachytherapy alone via flexible implant tubes. Single, double and triple plane implant was used in 6, 89 and 8 cases, respectively. The dose of boost brachytherapy and sole brachytherapy prescribed to dose reference points was 3 times 4.75 Gy and 7 times 5.2 Gy, respectively. The positions of dose reference points varied according to the level (2-D, semi-3-D and 3-D) of treatment planning performed. The treatment planning was based on the 3-D reconstruction of the surgical clips, implant tubes and skin points. In all cases the implantations were planned with a semi-3-D technique aided by simulator. In 10 cases a recently developed CT-guided 3-D planning system was used. The semi-3-D and 3-D treatment plans were compared to hypothetical 2-D plans using dose-volume histograms and dose non-uniformity ratios. The values of mean central dose, mean skin dose, minimal clip dose, proportion of underdosaged clips and mean target surface dose were evaluated. The accuracy of tumor bed localization and the conformity of planning target volume and treated volume were also analyzed in each technique. With the help of conformal semi-3-D and 3-D brachytherapy planning we could define reference dose points, active source positions and dwell times individually. This technique decreased the mean skin dose with 22.2% and reduced the possibility of geographical miss. We could achieve the best conformity between the planning target volume and the treated volume with the CT-image based 3-D treatment planning, at the cost of worse dose homogeneity. The mean treated volume was reduced by 25.1% with semi-3-D planning, however, it was increased by 16.2% with 3-D planning, compared to the 2-D planning. The application of clips into the tumor bed and the conformal (semi-3-D and 3-D) planning help to avoid geographical miss. CT is suitable for 3-D brachytherapy planning. Better local control with less side effects might be achieved with these new techniques. Conformal 3-D brachytherapy calls for new treatment planning concepts, taking the irregular 3-D shape of the target volume into account. The routine clinical application of image-based 3-D brachytherapy is a real aim in the very close future.

Imaging method for monitoring delivery of high dose rate brachytherapy

DOEpatents

Weisenberger, Andrew G; Majewski, Stanislaw

2012-10-23

A method for in-situ monitoring both the balloon/cavity and the radioactive source in brachytherapy treatment utilizing using at least one pair of miniature gamma cameras to acquire separate images of: 1) the radioactive source as it is moved in the tumor volume during brachytherapy; and 2) a relatively low intensity radiation source produced by either an injected radiopharmaceutical rendering cancerous tissue visible or from a radioactive solution filling a balloon surgically implanted into the cavity formed by the surgical resection of a tumor.

Selective perturbation of in vivo linear energy transfer using high- Z vaginal applicators for Cf-252 brachytherapy

NASA Astrophysics Data System (ADS)

Rivard, M. J.; Evans, K. E.; Leal, L. C.; Kirk, B. L.

2004-01-01

Californium-252 ( 252Cf) brachytherapy sources emit both neutrons and photons, and have the potential to vastly improve the current standard-of-practice for brachytherapy. While hydrogenous materials readily attenuate the 252Cf fission energy neutrons, high- Z materials are utilized to attenuate the 252Cf gamma-rays. These differences in shielding materials may be exploited when treating with a vaginal applicator to possibly improve patient survival through perturbation of the in vivo linear energy transfer radiation.

Prostate CT segmentation method based on nonrigid registration in ultrasound-guided CT-based HDR prostate brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xiaofeng, E-mail: xyang43@emory.edu; Rossi, Peter; Ogunleye, Tomi

2014-11-01

Purpose: The technological advances in real-time ultrasound image guidance for high-dose-rate (HDR) prostate brachytherapy have placed this treatment modality at the forefront of innovation in cancer radiotherapy. Prostate HDR treatment often involves placing the HDR catheters (needles) into the prostate gland under the transrectal ultrasound (TRUS) guidance, then generating a radiation treatment plan based on CT prostate images, and subsequently delivering high dose of radiation through these catheters. The main challenge for this HDR procedure is to accurately segment the prostate volume in the CT images for the radiation treatment planning. In this study, the authors propose a novel approachmore » that integrates the prostate volume from 3D TRUS images into the treatment planning CT images to provide an accurate prostate delineation for prostate HDR treatment. Methods: The authors’ approach requires acquisition of 3D TRUS prostate images in the operating room right after the HDR catheters are inserted, which takes 1–3 min. These TRUS images are used to create prostate contours. The HDR catheters are reconstructed from the intraoperative TRUS and postoperative CT images, and subsequently used as landmarks for the TRUS–CT image fusion. After TRUS–CT fusion, the TRUS-based prostate volume is deformed to the CT images for treatment planning. This method was first validated with a prostate-phantom study. In addition, a pilot study of ten patients undergoing HDR prostate brachytherapy was conducted to test its clinical feasibility. The accuracy of their approach was assessed through the locations of three implanted fiducial (gold) markers, as well as T2-weighted MR prostate images of patients. Results: For the phantom study, the target registration error (TRE) of gold-markers was 0.41 ± 0.11 mm. For the ten patients, the TRE of gold markers was 1.18 ± 0.26 mm; the prostate volume difference between the authors’ approach and the MRI-based volume was 7.28% ± 0.86%, and the prostate volume Dice overlap coefficient was 91.89% ± 1.19%. Conclusions: The authors have developed a novel approach to improve prostate contour utilizing intraoperative TRUS-based prostate volume in the CT-based prostate HDR treatment planning, demonstrated its clinical feasibility, and validated its accuracy with MRIs. The proposed segmentation method would improve prostate delineations, enable accurate dose planning and treatment delivery, and potentially enhance the treatment outcome of prostate HDR brachytherapy.« less

Prostate CT segmentation method based on nonrigid registration in ultrasound-guided CT-based HDR prostate brachytherapy

PubMed Central

Yang, Xiaofeng; Rossi, Peter; Ogunleye, Tomi; Marcus, David M.; Jani, Ashesh B.; Mao, Hui; Curran, Walter J.; Liu, Tian

2014-01-01

Purpose: The technological advances in real-time ultrasound image guidance for high-dose-rate (HDR) prostate brachytherapy have placed this treatment modality at the forefront of innovation in cancer radiotherapy. Prostate HDR treatment often involves placing the HDR catheters (needles) into the prostate gland under the transrectal ultrasound (TRUS) guidance, then generating a radiation treatment plan based on CT prostate images, and subsequently delivering high dose of radiation through these catheters. The main challenge for this HDR procedure is to accurately segment the prostate volume in the CT images for the radiation treatment planning. In this study, the authors propose a novel approach that integrates the prostate volume from 3D TRUS images into the treatment planning CT images to provide an accurate prostate delineation for prostate HDR treatment. Methods: The authors’ approach requires acquisition of 3D TRUS prostate images in the operating room right after the HDR catheters are inserted, which takes 1–3 min. These TRUS images are used to create prostate contours. The HDR catheters are reconstructed from the intraoperative TRUS and postoperative CT images, and subsequently used as landmarks for the TRUS–CT image fusion. After TRUS–CT fusion, the TRUS-based prostate volume is deformed to the CT images for treatment planning. This method was first validated with a prostate-phantom study. In addition, a pilot study of ten patients undergoing HDR prostate brachytherapy was conducted to test its clinical feasibility. The accuracy of their approach was assessed through the locations of three implanted fiducial (gold) markers, as well as T2-weighted MR prostate images of patients. Results: For the phantom study, the target registration error (TRE) of gold-markers was 0.41 ± 0.11 mm. For the ten patients, the TRE of gold markers was 1.18 ± 0.26 mm; the prostate volume difference between the authors’ approach and the MRI-based volume was 7.28% ± 0.86%, and the prostate volume Dice overlap coefficient was 91.89% ± 1.19%. Conclusions: The authors have developed a novel approach to improve prostate contour utilizing intraoperative TRUS-based prostate volume in the CT-based prostate HDR treatment planning, demonstrated its clinical feasibility, and validated its accuracy with MRIs. The proposed segmentation method would improve prostate delineations, enable accurate dose planning and treatment delivery, and potentially enhance the treatment outcome of prostate HDR brachytherapy. PMID:25370648

Efficacy of phosphorus-32 brachytherapy without external-beam radiation for long-term tumor control in patients with craniopharyngioma.

PubMed

Ansari, Shaheryar F; Moore, Reilin J; Boaz, Joel C; Fulkerson, Daniel H

2016-04-01

OBJECT Radioactive phosphorus-32 (P32) has been used as brachytherapy for craniopharyngiomas with the hope of providing local control of enlarging tumor cysts. Brachytherapy has commonly been used as an adjunct to the standard treatment of surgery and external-beam radiation (EBR). Historically, multimodal treatment, including EBR, has shown tumor control rates as high as 70% at 10 years after treatment. However, EBR is associated with significant long-term risks, including visual deficits, endocrine dysfunction, and cognitive decline. Theoretically, brachytherapy may provide focused local radiation that controls or shrinks a symptomatic cyst without exposing the patient to the risks of EBR. For this study, the authors reviewed their experiences with craniopharyngioma patients treated with P32 brachytherapy as the primary treatment without EBR. The authors reviewed these patients' records to evaluate whether this strategy effectively controls tumor growth, thus avoiding the need for further surgery or EBR. METHODS The authors performed a retrospective review of pediatric patients treated for craniopharyngioma between 1997 and 2004. This was the time period during which the authors' institution had a relatively high use of P32 for treatment of cystic craniopharyngioma. All patients who had surgery and injection of P32 without EBR were identified. The patient records were analyzed for complications, cyst control, need for further surgery, and need for future EBR. RESULTS Thirty-eight patients were treated for craniopharyngioma during the study period. Nine patients (23.7%) were identified who had surgery (resection or biopsy) with P32 brachytherapy but without initial EBR. These 9 patients represented the study group. For 1 patient (11.1%), there was a complication with the brachytherapy procedure. Five patients (55.5%) required subsequent surgery. Seven patients (77.7%) required subsequent EBR for tumor growth. The mean time between the injection of P32 and subsequent treatment was 1.67 ± 1.50 years (mean ± SD). CONCLUSIONS In this small but focused population, P32 treatment provided limited local control for cyst growth. Brachytherapy alone did not reliably avert the need for subsequent surgery or EBR.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Grace L.; Department of Health Services Research, The University of Texas MD Anderson Cancer Center, Houston, Texas; Jiang, Jing

Purpose: High-quality treatment for intact cervical cancer requires external radiation therapy, brachytherapy, and chemotherapy, carefully sequenced and completed without delays. We sought to determine how frequently current treatment meets quality benchmarks and whether new technologies have influenced patterns of care. Methods and Materials: By searching diagnosis and procedure claims in MarketScan, an employment-based health care claims database, we identified 1508 patients with nonmetastatic, intact cervical cancer treated from 1999 to 2011, who were <65 years of age and received >10 fractions of radiation. Treatments received were identified using procedure codes and compared with 3 quality benchmarks: receipt of brachytherapy, receipt ofmore » chemotherapy, and radiation treatment duration not exceeding 63 days. The Cochran-Armitage test was used to evaluate temporal trends. Results: Seventy-eight percent of patients (n=1182) received brachytherapy, with brachytherapy receipt stable over time (Cochran-Armitage P{sub trend}=.15). Among patients who received brachytherapy, 66% had high–dose rate and 34% had low–dose rate treatment, although use of high–dose rate brachytherapy steadily increased to 75% by 2011 (P{sub trend}<.001). Eighteen percent of patients (n=278) received intensity modulated radiation therapy (IMRT), and IMRT receipt increased to 37% by 2011 (P{sub trend}<.001). Only 2.5% of patients (n=38) received IMRT in the setting of brachytherapy omission. Overall, 79% of patients (n=1185) received chemotherapy, and chemotherapy receipt increased to 84% by 2011 (P{sub trend}<.001). Median radiation treatment duration was 56 days (interquartile range, 47-65 days); however, duration exceeded 63 days in 36% of patients (n=543). Although 98% of patients received at least 1 benchmark treatment, only 44% received treatment that met all 3 benchmarks. With more stringent indicators (brachytherapy, ≥4 chemotherapy cycles, and duration not exceeding 56 days), only 25% of patients received treatment that met all benchmarks. Conclusion: In this cohort, most cervical cancer patients received treatment that did not comply with all 3 benchmarks for quality treatment. In contrast to increasing receipt of newer radiation technologies, there was little improvement in receipt of essential treatment benchmarks.« less

Incidence of Secondary Cancer Development After High-Dose Intensity-Modulated Radiotherapy and Image-Guided Brachytherapy for the Treatment of Localized Prostate Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zelefsky, Michael J., E-mail: Zelefskm@mskcc.org; Housman, Douglas M.; Pei Xin

2012-07-01

Purpose: To report the incidence and excess risk of second malignancy (SM) development compared with the general population after external beam radiotherapy (EBRT) and brachytherapy to treat prostate cancer. Methods and Materials: Between 1998 and 2001, 1,310 patients with localized prostate cancer were treated with EBRT (n = 897) or brachytherapy (n = 413). We compared the incidence of SMs in our patients with that of the general population extracted from the National Cancer Institute's Surveillance, Epidemiology, and End Results data set combined with the 2000 census data. Results: The 10-year likelihood of SM development was 25% after EBRT andmore » 15% after brachytherapy (p = .02). The corresponding 10-year likelihood for in-field SM development in these groups was 4.9% and 1.6% (p = .24). Multivariate analysis showed that EBRT vs. brachytherapy and older age were the only significant predictors for the development of all SMs (p = .037 and p = .030), with a trend for older patients to develop a SM. The increased incidence of SM for EBRT patients was explained by the greater incidence of skin cancer outside the radiation field compared with that after brachytherapy (10.6% and 3.3%, respectively, p = .004). For the EBRT group, the 5- and 10-year mortality rate was 1.96% and 5.1% from out-of field cancer, respectively; for in-field SM, the corresponding mortality rates were 0.1% and 0.7%. Among the brachytherapy group, the 5- and 10-year mortality rate related to out-of field SM was 0.8% and 2.7%, respectively. Our observed SM rates after prostate RT were not significantly different from the cancer incidence rates in the general population. Conclusions: Using modern sophisticated treatment techniques, we report low rates of in-field bladder and rectal SM risks after prostate cancer RT. Furthermore, the likelihood of mortality secondary to a SM was unusual. The greater rate of SM observed with EBRT vs. brachytherapy was related to a small, but significantly increased, number of skin cancers in the EBRT patients compared with that of the general population.« less

Evaluation and implementation of triple‐channel radiochromic film dosimetry in brachytherapy

PubMed Central

Bradley, David; Nisbet, Andrew

2014-01-01

The measurement of dose distributions in clinical brachytherapy, for the purpose of quality control, commissioning or dosimetric audit, is challenging and requires development. Radiochromic film dosimetry with a commercial flatbed scanner may be suitable, but careful methodologies are required to control various sources of uncertainty. Triple‐channel dosimetry has recently been utilized in external beam radiotherapy to improve the accuracy of film dosimetry, but its use in brachytherapy, with characteristic high maximum doses, steep dose gradients, and small scales, has been less well researched. We investigate the use of advanced film dosimetry techniques for brachytherapy dosimetry, evaluating uncertainties and assessing the mitigation afforded by triple‐channel dosimetry. We present results on postirradiation film darkening, lateral scanner effect, film surface perturbation, film active layer thickness, film curling, and examples of the measurement of clinical brachytherapy dose distributions. The lateral scanner effect in brachytherapy film dosimetry can be very significant, up to 23% dose increase at 14 Gy, at ± 9 cm lateral from the scanner axis for simple single‐channel dosimetry. Triple‐channel dosimetry mitigates the effect, but still limits the useable width of a typical scanner to less than 8 cm at high dose levels to give dose uncertainty to within 1%. Triple‐channel dosimetry separates dose and dose‐independent signal components, and effectively removes disturbances caused by film thickness variation and surface perturbations in the examples considered in this work. The use of reference dose films scanned simultaneously with brachytherapy test films is recommended to account for scanner variations from calibration conditions. Postirradiation darkening, which is a continual logarithmic function with time, must be taken into account between the reference and test films. Finally, films must be flat when scanned to avoid the Callier‐like effects and to provide reliable dosimetric results. We have demonstrated that radiochromic film dosimetry with GAFCHROMIC EBT3 film and a commercial flatbed scanner is a viable method for brachytherapy dose distribution measurement, and uncertainties may be reduced with triple‐channel dosimetry and specific film scan and evaluation methodologies. PACS numbers: 87.55.Qr, 87.56.bg, 87.55.km PMID:25207417

Brachytherapy Application With In Situ Dose Painting Administered by Gold Nanoparticle Eluters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinha, Neeharika; Cifter, Gizem; Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts

Purpose: Recent studies show promise that administering gold nanoparticles (GNP) to tumor cells during brachytherapy could significantly enhance radiation damage to the tumor. A new strategy proposed for sustained administration of the GNP in prostate tumors is to load them into routinely used brachytherapy spacers for customizable in situ release after implantation. This in silico study investigated the intratumor biodistribution and corresponding dose enhancement over time due to GNP released from such GNP-loaded brachytherapy spacers (GBS). Method and Materials: An experimentally determined intratumoral diffusion coefficient (D) for 10-nm nanoparticles was used to estimate D for other sizes by using themore » Stokes-Einstein equation. GNP concentration profiles, obtained using D, were then used to calculate the corresponding dose enhancement factor (DEF) for each tumor voxel, using dose painting-by-numbers approach, for times relevant to the considered brachytherapy sources' lifetimes. The investigation was carried out as a function of GNP size for the clinically applicable low-dose-rate brachytherapy sources iodine-125 (I-125), palladium-103 (Pd-103), and cesium-131 (Cs-131). Results: Results showed that dose enhancement to tumor voxels and subvolumes during brachytherapy can be customized by varying the size of GNP released or eluted from the GBS. For example, using a concentration of 7 mg/g GNP, significant DEF (>20%) could be achieved 5 mm from a GBS after 5, 12, 25, 46, 72, 120, and 195 days, respectively, for GNP sizes of 2, 5, 10, 20, 30, and 50 nm and for 80 nm when treating with I-125. Conclusions: Analyses showed that using Cs-131 provides the highest dose enhancement to tumor voxels. However, given its relatively longer half-life, I-125 presents the most flexibility for customizing the dose enhancement as a function of GNP size. These findings provide a useful reference for further work toward development of potential new brachytherapy application with in situ dose painting administered via gold nanoparticle eluters for prostate cancer.« less

Prostate brachytherapy - discharge

MedlinePlus

... chap 84. Read More Prostate brachytherapy Prostate cancer Prostate-specific antigen (PSA) blood test Radical prostatectomy Review Date 2/21/2017 Updated by: Jennifer Sobol, DO, Urologist with the Michigan ... Cancer Browse the Encyclopedia A.D.A.M., ...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harkenrider, Matthew M., E-mail: mharkenrider@lumc.edu; Alite, Fiori; Silva, Scott R.

Cervical cancer is a disease that requires considerable multidisciplinary coordination of care and labor in order to maximize tumor control and survival while minimizing treatment-related toxicity. As with external beam radiation therapy, the use of advanced imaging and 3-dimensional treatment planning has generated a paradigm shift in the delivery of brachytherapy for the treatment of cervical cancer. The use of image-based brachytherapy, most commonly with magnetic resonance imaging (MRI), requires additional attention and effort by the treating physician to prescribe dose to the proper volume and account for adjacent organs at risk. This represents a dramatic change from the classicmore » Manchester approach of orthogonal radiographic images and prescribing dose to point A. We reviewed the history and currently evolving data and recommendations for the clinical use of image-based brachytherapy with an emphasis on MRI-based brachytherapy.« less

[Brachytherapy for head and neck cancers].

PubMed

Peiffert, D; Coche-Dequéant, B; Lapeyre, M; Renard, S

2018-05-29

The main indications of the brachytherapy of head and neck cancers are the limited tumours of the lip, the nose, the oral cavity and the oropharynx. Nasopharynx tumours are nowadays treated by intensity-modulated radiotherapy. This technique can be exclusive, associated with external radiotherapy or postoperative. It can also be a salvage treatment for the second primaries in previously irradiated areas. If the low dose rate brachytherapy rules remain the reference, the pulse dose rate technique allows the prescription of the dose rate and the optimisation of the dose distribution. Results of high dose rate brachytherapy are now published. This paper reports the recommendations of the Gec-ESTRO, published in 2017, and takes into account the data of the historical low dose rate series, and is upgraded with the pulsed-dose rate and high dose rate series. Copyright © 2018. Published by Elsevier SAS.

[Recurrence rate following adjuvant strontium-90 brachytherapy after excision of conjunctival melanoma].

PubMed

Krause, L; Ritter, C; Wachtlin, J; Kreusel, K-M; Höcht, S; Foerster, M H; Bechrakis, N E

2008-07-01

Because of the high local recurrence rates after excision of conjunctival melanomas, adjuvant local chemotherapy or irradiation is recommended. Strontium-90 brachytherapy is one radiotherapeutic option due to its low penetration depth. 15 patients with conjunctival melanoma were treated with adjuvant strontium-90 brachytherapy after tumour excision. The treatment was fractionated into 9 irradiation sessions with 6 Gy each. The mean follow-up was 35 months (12-60 months). Seven patients (46%) had no recurrence during the follow-up. Three patients (20%) had a recurrence in the treated or adjacent area. Eight patients (53%) developed new tumours in non-treated areas. Strontium-90 brachytherapy is a useful adjuvant in the treatment of conjunctival melanomas. Regular ophthalmoscopic controls are necessary because of the high rate of new tumours in non-irradiated areas, especially in cases with primary acquired melanosis.

High-dose-rate intraluminal brachytherapy prior to external radiochemotherapy in locally advanced esophageal cancer: preliminary results

PubMed Central

Safaei, Afsaneh Maddah; Ghalehtaki, Reza; Khanjani, Nezhat; Farazmand, Borna; Babaei, Mohammad

2017-01-01

Purpose Dysphagia is a common initial presentation in locally advanced esophageal cancer and negatively impacts patient quality of life and treatment compliance. To induce fast relief of dysphagia in patients with potentially operable esophageal cancer high-dose-rate (HDR) brachytherapy was applied prior to definitive radiochemotherapy. Material and methods In this single arm phase II clinical trial between 2013 to 2014 twenty patients with locally advanced esophageal cancer (17 squamous cell and 3 adenocarcinoma) were treated with upfront 10 Gy HDR brachytherapy, followed by 50.4 Gy external beam radiotherapy (EBRT) and concurrent chemotherapy with cisplatin/5-fluorouracil. Results Tumor response, as measured by endoscopy and/or computed tomography scan, revealed complete remission in 16 and partial response in 4 patients (overall response rate 100%). Improvement of dysphagia was induced by brachytherapy within a few days and maintained up to the end of treatment in 80% of patients. No differences in either response rate or dysphagia resolution were found between squamous cell and adenocarcinoma histology. The grade 2 and 3 acute pancytopenia or bicytopenia reported in 4 patients, while sub-acute adverse effects with painful ulceration was seen in five patients, occurring after a median of 2 months. A perforation developed in one patient during the procedure of brachytherapy that resolved successfully with immediate surgery. Conclusions Brachytherapy before EBRT was a safe and effective procedure to induce rapid and durable relief from dysphagia, especially when combined with EBRT. PMID:28344601

High Dose Rate Brachytherapy in Two 9 Gy Fractions in the Treatment of Locally Advanced Cervical Cancer - a South Indian Institutional Experience.

PubMed

Ghosh, Saptarshi; Rao, Pamidimukkala Bramhananda; Kotne, Sivasankar

2015-01-01

Although 3D image based brachytherapy is currently the standard of treatment in cervical cancer, most of the centres in developing countries still practice orthogonal intracavitary brachytherapy due to financial constraints. The quest for optimum dose and fractionation schedule in high dose rate (HDR) intracavitary brachytherapy (ICBT) is still ongoing. While the American Brachytherapy Society recommends four to eight fractions of each less than 7.5 Gy, there are some studies demonstrating similar efficacy and comparable toxicity with higher doses per fraction. To assess the treatment efficacy and late complications of HDR ICBT with 9 Gy per fraction in two fractions. This is a prospective institutional study in Southern India carried on from 1st June 2012 to 31st July 2014. In this period, 76 patients of cervical cancer satisfying our inclusion criteria were treated with concurrent chemo-radiation following ICBT with 9 Gy per fraction in two fractions, five to seven days apart. The median follow-up period in the study was 24 months (range 10.6 - 31.2 months). The 2 year actuarial local control rate, disease-free survival and overall survival were 88.1%, 84.2% and 81.8% respectively. Although 38.2% patients suffered from late toxicity, only 3 patients had grade III late toxicity. In our experience, HDR brachytherapy with 9 Gy per fraction in two fractions is an effective dose fractionation for the treatment of cervical cancer with acceptable toxicity.

Clinical outcomes from an innovative protocol using serial ultrasound imaging and a single MR image to guide brachytherapy for locally advanced cervix cancer.

PubMed

van Dyk, Sylvia; Narayan, Kailash; Bernshaw, David; Kondalsamy-Chennakesavan, Srinivas; Khaw, Pearly; Lin, Ming Yin; Schneider, Michal

The aim of this study was to report clinical outcomes in a series of patients who underwent serial ultrasound and a single MRI to plan and verify intracavitary brachytherapy. Data for patients who were referred for curative intent radiotherapy for International Federation of Gynecology and Obstetrics (FIGO) Stage 1-1V cervix cancer between January 2007 and March 2012 were analyzed. All patients received external beam radiotherapy with concurrent chemotherapy and sequential high-dose rate brachytherapy. Brachytherapy was planned and verified using serial ultrasound imaging and a single MRI. Data from 191 patients were available for analyses. The median (range) followup time was 5.08 (0.25-8.25) years. Five-year local control, failure-free survival, cancer-specific survival, and overall survival were 86%, 57.3%, 70% and 63%, respectively. Mean (standard deviation) combined external beam radiotherapy and brachytherapy target doses, equivalent to doses in 2 Gy fractions were 80.4 Gy10 (3.89), median (range) 80 (49-96) Gy10. Grade 3 or greater gastrointestinal, genitourinary, or vaginal late toxicity occurred in 3%, 1.6%, and 2% of patients, respectively. Survival, patterns of failure, and late complication rates were similar to published series of MRI/CT-based brachytherapy practices. This large study demonstrates that favorable treatment outcomes can be obtained using a pragmatic and innovative combination of ultrasound and MR imaging. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

New Breast Cancer Radiotherapy Technology Confers Higher Complications and Costs Before Effectiveness Proven: A Medicare Data Analysis

PubMed Central

Walter, Dawn; Tousimis, Eleni; Hayes, Mary Katherine

2018-01-01

A new breast cancer treatment, brachytherapy-based accelerated partial breast radiotherapy (RT), was adopted before long-term effectiveness evidence, potentially increasing morbidity and costs compared with whole breast RT. The aim of this study was to estimate complication rates and RT-specific and 1-year costs for a cohort of female Medicare beneficiaries diagnosed with breast cancer (N = 47 969). We analyzed 2005-2007 Medicare claims using multivariable logistic regression for complications and generalized linear models (log link, gamma distribution) for costs. Overall, 11% (n = 5296) underwent brachytherapy-based RT; 9.4% had complications. Odds of any complication were higher (odds ratio [OR]: 1.62; 95% confidence interval [CI]: 1.49-1.76) for brachytherapy versus whole breast RT, similarly to seroma (OR: 2.85; 95% CI: 1.97-4.13), wound complication/infection (OR: 1.72; 95% CI: 1.52-1.95), cellulitis (OR: 1.48; 95% CI: 1.27-1.73), and necrosis (OR: 2.07; 95% CI: 1.55-2.75). Mean RT-specific and 1-year total costs for whole breast RT were $6375, and $19 917, $4886, and $4803 lower than brachytherapy (P < .0001). Multivariable analyses indicated brachytherapy yielded 76% higher RT costs (risk ratio: 1.76; 95% CI: 1.74-1.78, P < .0001) compared with whole breast RT. Brachytherapy had higher complications and costs before long-term evidence proved its effectiveness. Policies should require treatment registries with reimbursement incentives to capture surveillance data for new technologies. PMID:29502466

MO-B-BRC-04: MRI-Based Prostate HDR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mourtada, F.

2016-06-15

Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR ismore » U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.« less

MO-B-BRC-00: Prostate HDR Treatment Planning - Considering Different Imaging Modalities

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2016-06-15

Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR ismore » U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.« less

MO-B-BRC-02: Ultrasound Based Prostate HDR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Z.

2016-06-15

Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR ismore » U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.« less

WE-AB-BRA-12: Post-Implant Dosimetry in Prostate Brachytherapy by X-Ray and MRI Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, S; Song, D; Lee, J

Purpose: For post-implant dosimetric assessment after prostate brachytherapy, CT-MR fusion approach has been advocated due to the superior accuracy on both seeds localization and soft tissue delineation. However, CT deposits additional radiation to the patient, and seed identification in CT requires manual review and correction. In this study, we propose an accurate, low-dose, and cost-effective post-implant dosimetry approach based on X-ray and MRI. Methods: Implanted seeds are reconstructed using only three X-ray fluoroscopy images by solving a combinatorial optimization problem. The reconstructed seeds are then registered to MR images using an intensity-based points-to-volume registration. MR images are first pre-processed bymore » geometric and Gaussian filtering, yielding smooth candidate seed-only images. To accommodate potential soft tissue deformation, our registration is performed in two steps, an initial affine followed by local deformable registrations. An evolutionary optimizer in conjunction with a points-to-volume similarity metric is used for the affine registration. Local prostate deformation and seed migration are then adjusted by the deformable registration step with external and internal force constraints. Results: We tested our algorithm on twenty patient data sets. For quantitative evaluation, we obtained ground truth seed positions by fusing the post-implant CT-MR images. Seeds were semi-automatically extracted from CT and manually corrected and then registered to the MR images. Target registration error (TRE) was computed by measuring the Euclidean distances from the ground truth to the closest registered X-ray seeds. The overall TREs (mean±standard deviation in mm) are 1.6±1.1 (affine) and 1.3±0.8 (affine+deformable). The overall computation takes less than 1 minute. Conclusion: It has been reported that the CT-based seed localization error is ∼1.6mm and the seed localization uncertainty of 2mm results in less than 5% deviation of prostate D90. The average error of 1.3mm with our system outperforms the CT-based approach and is considered well within the clinically acceptable limit. Supported in part by NIH/NCI grant 5R01CA151395. The X-ray-based implant reconstruction method (US patent No. 8,233,686) was licensed to Acoustic MedSystems Inc.« less

CT-based MCNPX dose calculations for gynecology brachytherapy employing a Henschke applicator

NASA Astrophysics Data System (ADS)

Yu, Pei-Chieh; Nien, Hsin-Hua; Tung, Chuan-Jong; Lee, Hsing-Yi; Lee, Chung-Chi; Wu, Ching-Jung; Chao, Tsi-Chian

2017-11-01

The purpose of this study is to investigate the dose perturbation caused by the metal ovoid structures of a Henschke applicator using Monte Carlo simulation in a realistic phantom. The Henschke applicator has been widely used for gynecologic patients treated by brachytherapy in Taiwan. However, the commercial brachytherapy planning system (BPS) did not properly evaluate the dose perturbation caused by its metal ovoid structures. In this study, Monte Carlo N-Particle Transport Code eXtended (MCNPX) was used to evaluate the brachytherapy dose distribution of a Henschke applicator embedded in a Plastic water phantom and a heterogeneous patient computed tomography (CT) phantom. The dose comparison between the MC simulations and film measurements for a Plastic water phantom with Henschke applicator were in good agreement. However, MC dose with the Henschke applicator showed significant deviation (-80.6%±7.5%) from those without Henschke applicator. Furthermore, the dose discrepancy in the heterogeneous patient CT phantom and Plastic water phantom CT geometries with Henschke applicator showed 0 to -26.7% dose discrepancy (-8.9%±13.8%). This study demonstrates that the metal ovoid structures of Henschke applicator cannot be disregard in brachytherapy dose calculation.

Brachytherapy after salvage surgery in cases with large isolated cervical recurrence of squamous cell carcinoma in the previously irradiated neck.

PubMed

Miroir, Jessica; Biau, Julian; Saroul, Nicolas; Moreira, Jean-François; Russier, Marc; Lapeyre, Michel

2016-09-01

Perioperative brachytherapy after salvage surgery is a therapeutic option in patients with cervical relapse of a primary, controlled, previously irradiated head and neck squamous cell carcinoma. The purpose of this study was to analyze the outcome of this treatment. Between 2008 and 2013, 8 patients underwent cervical brachytherapy after neck dissection. The mean node size was 5.5 cm. Recurrence occurred in an irradiated field (median dose, 50 Gy). Brachytherapy was performed with (192) iridium and dosimetry in accord with the rules of the Paris system. The dose was 60 to 62.7 Gy on the reference isodose. The mean follow-up was 17 months. The median overall survival (OS) was 12 months. The OS was 19% at 2 years and 0% at 5 years. A grade 5 postoperative adverse event occurred in 1 patient. At 6 months, all patients had a grade 3 neck soft tissue fibrosis. One patient had a lethal hemorrhage at 56 months. Brachytherapy is toxic in this population with poor OS. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2490-E2494, 2016. © 2016 Wiley Periodicals, Inc.

Physics-aspects of dose accuracy in high dose rate (HDR) brachytherapy: source dosimetry, treatment planning, equipment performance and in vivo verification techniques

PubMed Central

Bradley, David; Nisbet, Andrew

2012-01-01

This study provides a review of recent publications on the physics-aspects of dosimetric accuracy in high dose rate (HDR) brachytherapy. The discussion of accuracy is primarily concerned with uncertainties, but methods to improve dose conformation to the prescribed intended dose distribution are also noted. The main aim of the paper is to review current practical techniques and methods employed for HDR brachytherapy dosimetry. This includes work on the determination of dose rate fields around brachytherapy sources, the capability of treatment planning systems, the performance of treatment units and methods to verify dose delivery. This work highlights the determinants of accuracy in HDR dosimetry and treatment delivery and presents a selection of papers, focusing on articles from the last five years, to reflect active areas of research and development. Apart from Monte Carlo modelling of source dosimetry, there is no clear consensus on the optimum techniques to be used to assure dosimetric accuracy through all the processes involved in HDR brachytherapy treatment. With the exception of the ESTRO mailed dosimetry service, there is little dosimetric audit activity reported in the literature, when compared with external beam radiotherapy verification. PMID:23349649

Physics-aspects of dose accuracy in high dose rate (HDR) brachytherapy: source dosimetry, treatment planning, equipment performance and in vivo verification techniques.

PubMed

Palmer, Antony; Bradley, David; Nisbet, Andrew

2012-06-01

This study provides a review of recent publications on the physics-aspects of dosimetric accuracy in high dose rate (HDR) brachytherapy. The discussion of accuracy is primarily concerned with uncertainties, but methods to improve dose conformation to the prescribed intended dose distribution are also noted. The main aim of the paper is to review current practical techniques and methods employed for HDR brachytherapy dosimetry. This includes work on the determination of dose rate fields around brachytherapy sources, the capability of treatment planning systems, the performance of treatment units and methods to verify dose delivery. This work highlights the determinants of accuracy in HDR dosimetry and treatment delivery and presents a selection of papers, focusing on articles from the last five years, to reflect active areas of research and development. Apart from Monte Carlo modelling of source dosimetry, there is no clear consensus on the optimum techniques to be used to assure dosimetric accuracy through all the processes involved in HDR brachytherapy treatment. With the exception of the ESTRO mailed dosimetry service, there is little dosimetric audit activity reported in the literature, when compared with external beam radiotherapy verification.

Risk of Late Urinary Complications Following Image Guided Adaptive Brachytherapy for Locally Advanced Cervical Cancer: Refining Bladder Dose-Volume Parameters.

PubMed

Manea, Elena; Escande, Alexandre; Bockel, Sophie; Khettab, Mohamed; Dumas, Isabelle; Lazarescu, Ioana; Fumagalli, Ingrid; Morice, Philippe; Deutsch, Eric; Haie-Meder, Christine; Chargari, Cyrus

2018-06-01

To study correlations between dose-volume parameters of the whole bladder and bladder trigone and late urinary toxicity in locally advanced cervical cancer patients treated with pulsed-dose-rate brachytherapy. Patients with locally advanced cervical cancer treated with chemoradiation therapy and pulsed-dose-rate brachytherapy from 2004 to 2015 were included. Cumulative dose-volume parameters of the whole bladder and bladder trigone were converted into 2-Gy/fraction equivalents (EQD2, with α/β = 3 Gy); these parameters, as well as clinical factors, were analyzed as predictors of toxicity in patients without local relapse. A total of 297 patients fulfilled the inclusion criteria. The median follow-up period was 4.9 years (95% confidence interval 4.5-5.3 years). In patients without local relapse (n = 251), the Kaplan-Meier estimated grade 2 or higher urinary toxicity rates at 3 years and 5 years were 25.4% and 32.1%, respectively. Minimal dose to the most exposed 2 cm 3 of the whole bladder [Formula: see text] , bladder International Commission on Radiation Units & Measurements (ICRU) (B ICRU ) dose, and trigone dose-volume parameters correlated with grade 2 or higher toxicity. At 3 years, the cumulative incidence of grade 2 or higher complications was 22.8% (standard error, 2.9%) for bladder [Formula: see text]  < 80 Gy EQD2 versus 61.8% (standard error, 12.7%) for [Formula: see text]  ≥ 80 Gy EQD2 (P = .001). In the subgroup of patients with bladder [Formula: see text]  ≤ 80 Gy EQD2 , a trigone dose delivered to 50% of the volume (D 50% ) > 60 Gy EQD2 was significant for grade 2 or higher toxicity (P = .027). The probability of grade 3 or higher toxicities increased with bladder [Formula: see text]  > 80 Gy EQD2 (16.7% vs 1.6%; hazard ratio [HR], 5.77; P = .039), B ICRU dose > 65 Gy EQD2 (4.9% vs 1.3%; HR, 6.36; P = .018), and trigone D 50%  > 60 Gy EQD2 (3.1% vs 1.2%; HR, 6.29; P = .028). Pearson correlation coefficients showed a moderate correlation between bladder [Formula: see text] , B ICRU dose, and bladder trigone D 50% (P < .0001). These data suggest that [Formula: see text]  ≤ 80 Gy EQD2 should be advised for minimizing the risk of severe urinary complications (<15%). Bladder trigone dose was also predictive of severe late urinary toxicity. These constraints need further confirmation in a multicenter prospective setting. Copyright © 2018 Elsevier Inc. All rights reserved.

Proficiency-based cervical cancer brachytherapy training.

PubMed

Zhao, Sherry; Francis, Louise; Todor, Dorin; Fields, Emma C

2018-04-25

Although brachytherapy increases the local control rate for cervical cancer, there has been a progressive decline in its use. Furthermore, the training among residency programs for gynecologic brachytherapy varies considerably, with some residents receiving little to no training. This trend is especially concerning given the association between poor applicator placement and decline in local control. Considering the success of proficiency-based training in other procedural specialties, we developed and implemented a proficiency-based cervical brachytherapy training curriculum for our residents. Each resident placed tandem and ovoid applicators with attending guidance and again alone 2 weeks later using a pelvic model that was modified to allow for cervical brachytherapy. Plain films were taken of the pelvic model, and applicator placement quality was evaluated. Other evaluated metrics included retention of key procedural details, the time taken for each procedure and presession and postsession surveys to assess confidence. During the initial session, residents on average met 4.5 of 5 placement criteria, which improved to 5 the second session. On average, residents were able to remember 7.6 of the 8 key procedural steps. Execution time decreased by an average of 10.5%. Resident confidence with the procedure improved dramatically, from 2.6 to 4.6 of 5. Residents who had previously never performed a tandem and ovoid procedure showed greater improvements in these criteria than those who had. All residents strongly agreed that the training was helpful and wanted to participate again the following year. Residents participating in this simulation training had measurable improvements in the time to perform the procedure, applicator placement quality, and confidence. This curriculum is easy to implement and is of great value for training residents, and would be particularly beneficial in programs with low volume of cervical brachytherapy cases. Simulation programs could also be created for other technically challenging radiation oncology procedures. Copyright © 2018 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

For-profit hospital ownership status and use of brachytherapy after breast-conserving surgery.

PubMed

Sen, Sounok; Soulos, Pamela R; Herrin, Jeph; Roberts, Kenneth B; Yu, James B; Lesnikoski, Beth-Ann; Ross, Joseph S; Krumholz, Harlan M; Gross, Cary P

2014-05-01

Little is known about the relationship between operative care for breast cancer at for-profit hospitals and subsequent use of adjuvant radiation therapy (RT). Among Medicare beneficiaries, we examined whether hospital ownership status is associated with the use of breast brachytherapy--a newer and more expensive modality--as well as overall RT. We conducted a retrospective study of female Medicare beneficiaries who received breast-conserving surgery for invasive breast cancer in 2008 and 2009. We assessed the relationship between hospital ownership and receipt of brachytherapy or overall RT by using hierarchical generalized linear models. The sample consisted of 35,118 women, 8.0% of whom had breast-conserving operations at for-profit hospitals. Among patients who received RT, those who underwent operation at for-profit hospitals were more likely to receive brachytherapy (20.2%) than patients treated at not-for-profit hospitals (15.2%; odds ratio [OR] for for-profit versus not-for-profit: 1.50; 95% confidence interval [95% CI] 1.23-1.84; P < .001). Among women aged 66-79 years, there was no relationship between hospital ownership status and overall use of RT. Among women ages 80-94 years of age--the group least likely to benefit from RT due to shorter life expectancy--undergoing breast-conserving operations at a for-profit hospital was associated with greater overall use of RT (OR 1.22; 95% CI 1.03-1.45, P = .03) and brachytherapy use (OR 1.66; 95% CI 1.18-2.34, P = .003). Operative care at for-profit hospitals was associated with increased use of the newer and more expensive RT modality, brachytherapy. Among the oldest women who are least likely to benefit from RT, operative care at a for-profit hospital was associated with greater overall use of RT, with this difference largely driven by the use of brachytherapy. Copyright © 2014 Mosby, Inc. All rights reserved.

For-Profit Hospital Ownership Status and Use of Brachytherapy after Breast-Conserving Surgery

PubMed Central

Sen, Sounok; Soulos, Pamela R.; Herrin, Jeph; Roberts, Kenneth B.; Yu, James B.; Lesnikoski, Beth-Ann; Ross, Joseph S.; Krumholz, Harlan M.; Gross, Cary P.

2014-01-01

BACKGROUND Little is known about the relation between surgical care for breast cancer at for-profit hospitals and subsequent use of adjuvant radiation therapy (RT). Among Medicare beneficiaries, we examined whether hospital ownership status is associated with the use of breast brachytherapy – a newer and more expensive modality – as well as overall RT. METHODS We conducted a retrospective study of female Medicare beneficiaries receiving breast-conserving surgery for invasive breast cancer in 2008 and 2009. We assessed the relationship between hospital ownership and receipt of brachytherapy or overall RT using hierarchical generalized linear models. RESULTS The sample consisted of 35,118 women, 8.0% of whom had surgery at for-profit hospitals. Among patients who received RT, those who underwent surgery at for-profit hospitals were significantly more likely to receive brachytherapy (20.2%) than patients treated at not-for-profit hospitals (15.2%; OR for for-profit vs. not-for-profit: 1.50; 95%CI: 1.23–1.84; p<0.001). Among women aged 66–79, there was no relation between hospital ownership status and overall RT use. Among women aged 80–94 years old – the group least likely to benefit from RT due to shorter life expectancy – receipt of surgery at a for-profit hospital was significantly associated with higher overall RT use (OR: 1.22; 95%CI: 1.03–1.45, p=0.03) and brachytherapy use (OR: 1.66; 95%CI: 1.18–2.34, p=0.003). CONCLUSIONS Surgical care at for-profit hospitals was associated with increased use of the newer and more expensive RT modality, brachytherapy. Among the oldest women, who are least likely to benefit from RT, surgical care at a for-profit hospital was associated with higher overall RT use, with this difference largely driven by the use of brachytherapy. PMID:24787104

Determination of the intrinsic energy dependence of LiF:Mg,Ti thermoluminescent dosimeters for {sup 125}I and {sup 103}Pd brachytherapy sources relative to {sup 60}Co

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reed, J. L., E-mail: jlreed2@wisc.edu; Micka, J. A.; Culberson, W. S.

Purpose: To determine the intrinsic energy dependence of LiF:Mg,Ti thermoluminescent dosimeters (TLD-100) for {sup 125}I and {sup 103}Pd brachytherapy sources relative to {sup 60}Co. Methods: LiF:Mg,Ti TLDs were irradiated with low-energy brachytherapy sources and with a {sup 60}Co teletherapy source. The brachytherapy sources measured were the Best 2301 {sup 125}I seed, the OncoSeed 6711 {sup 125}I seed, and the Best 2335 {sup 103}Pd seed. The TLD light output per measured air-kerma strength was determined for the brachytherapy source irradiations, and the TLD light output per air kerma was determined for the {sup 60}Co irradiations. Monte Carlo (MC) simulations were usedmore » to calculate the dose-to-TLD rate per air-kerma strength for the brachytherapy source irradiations and the dose to TLD per air kerma for the {sup 60}Co irradiations. The measured and MC-calculated results for all irradiations were used to determine the TLD intrinsic energy dependence for {sup 125}I and {sup 103}Pd relative to {sup 60}Co. Results: The relative TLD intrinsic energy dependences (relative to {sup 60}Co) and associated uncertainties (k = 1) were determined to be 0.883 ± 1.3%, 0.870 ± 1.4%, and 0.871 ± 1.5% for the Best 2301 seed, OncoSeed 6711 seed, and Best 2335 seed, respectively. Conclusions: The intrinsic energy dependence of TLD-100 is dependent on photon energy, exhibiting changes of 13%–15% for {sup 125}I and {sup 103}Pd sources relative to {sup 60}Co. TLD measurements of absolute dose around {sup 125}I and {sup 103}Pd brachytherapy sources should explicitly account for the relative TLD intrinsic energy dependence in order to improve dosimetric accuracy.« less

Quality of life after open or robotic prostatectomy, cryoablation or brachytherapy for localized prostate cancer.

PubMed

Malcolm, John B; Fabrizio, Michael D; Barone, Bethany B; Given, Robert W; Lance, Raymond S; Lynch, Donald F; Davis, John W; Shaves, Mark E; Schellhammer, Paul F

2010-05-01

Health related quality of life concerns factor prominently in prostate cancer management. We describe health related quality of life impact and recovery profiles of 4 commonly used operative treatments for localized prostate cancer. Beginning in February 2000 all patients treated with open radical prostatectomy, robot assisted laparoscopic prostatectomy, brachytherapy or cryotherapy were asked to complete the UCLA-PCI questionnaire before treatment, and at 3, 6, 12, 18, 24, 30 and 36 months after treatment. Outcomes were compared across treatment types with statistical analysis using univariate and multivariate models. A total of 785 patients treated between February 2000 and December 2008 were included in the analysis with a mean followup of 24 months. All health related quality of life domains were adversely affected by all treatments and recovery profiles varied significantly by treatment type. Overall urinary function and bother outcomes scored significantly higher after brachytherapy and cryotherapy compared to open radical prostatectomy and robotic assisted laparoscopic radical prostatectomy. Brachytherapy and cryotherapy had a 3-fold higher rate of return to baseline urinary function compared to open radical prostatectomy and robotic assisted laparoscopic radical prostatectomy. Sexual function and bother scores were highest after brachytherapy, with a 5-fold higher rate of return to baseline function compared to cryotherapy, open radical prostatectomy and robotic assisted laparoscopic radical prostatectomy. All 4 treatments were associated with relatively transient and less pronounced impact on bowel function and bother. In a study of sequential health related quality of life assessments brachytherapy and cryotherapy were associated with higher urinary function and bother scores compared to open radical prostatectomy and da Vinci prostatectomy. Brachytherapy was associated with higher sexual function and bother scores compared to open radical prostatectomy, robotic assisted laparoscopic radical prostatectomy and cryotherapy. 2010 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

SU-E-T-205: Improving Quality Assurance of HDR Brachytherapy: Verifying Agreement Between Planned and Delivered Dose Distributions Using DICOM RTDose and Advanced Film Dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmer, A L; University of Surrey, Guildford, Surrey; Bradley, D A

Purpose: HDR brachytherapy is undergoing significant development, and quality assurance (QA) checks must keep pace. Current recommendations do not adequately verify delivered against planned dose distributions: This is particularly relevant for new treatment planning system (TPS) calculation algorithms (non TG-43 based), and an era of significant patient-specific plan optimisation. Full system checks are desirable in modern QA recommendations, complementary to device-centric individual tests. We present a QA system incorporating TPS calculation, dose distribution export, HDR unit performance, and dose distribution measurement. Such an approach, more common in external beam radiotherapy, has not previously been reported in the literature for brachytherapy.more » Methods: Our QA method was tested at 24 UK brachytherapy centres. As a novel approach, we used the TPS DICOM RTDose file export to compare planned dose distribution with that measured using Gafchromic EBT3 films placed around clinical brachytherapy treatment applicators. Gamma analysis was used to compare the dose distributions. Dose difference and distance to agreement were determined at prescription Point A. Accurate film dosimetry was achieved using a glass compression plate at scanning to ensure physically-flat films, simultaneous scanning of known dose films with measurement films, and triple-channel dosimetric analysis. Results: The mean gamma pass rate of RTDose compared to film-measured dose distributions was 98.1% at 3%(local), 2 mm criteria. The mean dose difference, measured to planned, at Point A was -0.5% for plastic treatment applicators and -2.4% for metal applicators, due to shielding not accounted for in TPS. The mean distance to agreement was 0.6 mm. Conclusion: It is recommended to develop brachytherapy QA to include full-system verification of agreement between planned and delivered dose distributions. This is a novel approach for HDR brachytherapy QA. A methodology using advanced film dosimetry and gamma comparison to DICOM RTDose files has been demonstrated as suitable to fulfil this need.« less

Phase III randomized trial comparing LDR and HDR brachytherapy in treatment of cervical carcinoma.

PubMed

Lertsanguansinchai, Prasert; Lertbutsayanukul, Chawalit; Shotelersuk, Kanjana; Khorprasert, Chonlakiet; Rojpornpradit, Prayuth; Chottetanaprasith, Taywin; Srisuthep, Apiradee; Suriyapee, Sivalee; Jumpangern, Chotika; Tresukosol, Damrong; Charoonsantikul, Chulee

2004-08-01

Intracavitary brachytherapy plays an important role in the treatment of cervical carcinoma. Previous results have shown controversy between the effect of dose rate on tumor control and the occurrence of complications. We performed a prospective randomized clinical trial to compare the clinical outcomes between low-dose-rate (LDR) and high-dose-rate (HDR) intracavitary brachytherapy for treatment of invasive uterine cervical carcinoma. A total of 237 patients with previously untreated invasive carcinoma of the uterine cervix treated at King Chulalongkorn Memorial Hospital were randomized between June 1995 and December 2001. Excluding ineligible, incomplete treatment, and incomplete data patients, 109 and 112 patients were in the LDR and HDR groups, respectively. All patients were treated with external beam radiotherapy and LDR or HDR intracavitary brachytherapy using the Chulalongkorn treatment schedule. The median follow-up for the LDR and HDR groups was 40.2 and 37.2 months, respectively. The actuarial 3-year overall and relapse-free survival rate for all patients was 69.6% and 70%, respectively. The 3-year overall survival rate in the LDR and HDR groups was 70.9% and 68.4% (p = 0.75) and the 3-year pelvic control rate was 89.1% and 86.4% (p = 0.51), respectively. The 3-year relapse-free survival rate in both groups was 69.9% (p = 0.35). Most recurrences were distant metastases, especially in Stage IIB and IIIB patients. Grade 3 and 4 complications were found in 2.8% and 7.1% of the LDR and HDR groups (p = 0.23). Comparable outcomes were demonstrated between LDR and HDR intracavitary brachytherapy. Concerning patient convenience, the lower number of medical personnel needed, and decreased radiation to health care workers, HDR intracavitary brachytherapy is an alternative to conventional LDR brachytherapy. The high number of distant failure suggests that other modalities such as systemic concurrent or adjuvant chemotherapy might lower this high recurrence, especially in Stage IIB and IIIB.

Modelling second malignancy risks from low dose rate and high dose rate brachytherapy as monotherapy for localised prostate cancer.

PubMed

Murray, Louise; Mason, Joshua; Henry, Ann M; Hoskin, Peter; Siebert, Frank-Andre; Venselaar, Jack; Bownes, Peter

2016-08-01

To estimate the risks of radiation-induced rectal and bladder cancers following low dose rate (LDR) and high dose rate (HDR) brachytherapy as monotherapy for localised prostate cancer and compare to external beam radiotherapy techniques. LDR and HDR brachytherapy monotherapy plans were generated for three prostate CT datasets. Second cancer risks were assessed using Schneider's concept of organ equivalent dose. LDR risks were assessed according to a mechanistic model and a bell-shaped model. HDR risks were assessed according to a bell-shaped model. Relative risks and excess absolute risks were estimated and compared to external beam techniques. Excess absolute risks of second rectal or bladder cancer were low for both LDR (irrespective of the model used for calculation) and HDR techniques. Average excess absolute risks of rectal cancer for LDR brachytherapy according to the mechanistic model were 0.71 per 10,000 person-years (PY) and 0.84 per 10,000 PY respectively, and according to the bell-shaped model, were 0.47 and 0.78 per 10,000 PY respectively. For HDR, the average excess absolute risks for second rectal and bladder cancers were 0.74 and 1.62 per 10,000 PY respectively. The absolute differences between techniques were very low and clinically irrelevant. Compared to external beam prostate radiotherapy techniques, LDR and HDR brachytherapy resulted in the lowest risks of second rectal and bladder cancer. This study shows both LDR and HDR brachytherapy monotherapy result in low estimated risks of radiation-induced rectal and bladder cancer. LDR resulted in lower bladder cancer risks than HDR, and lower or similar risks of rectal cancer. In absolute terms these differences between techniques were very small. Compared to external beam techniques, second rectal and bladder cancer risks were lowest for brachytherapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Perioperative Interstitial High-Dose-Rate Brachytherapy for the Treatment of Recurrent Keloids: Feasibility and Early Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Ping, E-mail: ping.jiang@uksh.de; Baumann, René; Dunst, Juergen

Purpose: To prospectively evaluate high-dose-rate brachytherapy in the treatment of therapy-resistant keloids and report first results, with emphasis on feasibility and early treatment outcome. Methods and Materials: From 2009 to 2014, 24 patients with 32 recurrent keloids were treated with immediate perioperative high-dose-rate brachytherapy; 3 patients had been previously treated with adjuvant external beam radiation therapy and presented with recurrences in the pretreated areas. Two or more different treatment modalities had been tried in all patients and had failed to achieve remission. After (re-)excision of the keloids, a single brachytherapy tube was placed subcutaneously before closing the wound. The target volumemore » covered the scar in total length. Brachytherapy was given in 3 fractions with a single dose of 6 Gy in 5 mm tissue depth. The first fraction was given within 6 hours after surgery, the other 2 fractions on the first postoperative day. Thus, a total dose of 18 Gy in 3 fractions was administered within 36 hours after the resection. Results: The treatment was feasible in all patients. No procedure-related complications (eg, secondary infections) occurred. Nineteen patients had keloid-related symptoms before treatment like pain and pruritus; disappearance of symptoms was noticed in all patients after treatment. After a median follow-up of 29.4 months (range, 7.9-72.4 months), 2 keloid recurrences and 2 mildly hypertrophied scars were observed. The local control rate was 94%. Pigmentary abnormalities were detected in 3 patients, and an additional 6 patients had a mild delay in the wound-healing process. Conclusions: The early results of this study prove the feasibility and the efficacy of brachytherapy for the prevention of keloids. The results also suggest that brachytherapy may be advantageous in the management of high-risk keloids or as salvage treatment for failure after external beam therapy.« less

Patient-specific Monte Carlo-based dose-kernel approach for inverse planning in afterloading brachytherapy.

PubMed

D'Amours, Michel; Pouliot, Jean; Dagnault, Anne; Verhaegen, Frank; Beaulieu, Luc

2011-12-01

Brachytherapy planning software relies on the Task Group report 43 dosimetry formalism. This formalism, based on a water approximation, neglects various heterogeneous materials present during treatment. Various studies have suggested that these heterogeneities should be taken into account to improve the treatment quality. The present study sought to demonstrate the feasibility of incorporating Monte Carlo (MC) dosimetry within an inverse planning algorithm to improve the dose conformity and increase the treatment quality. The method was based on precalculated dose kernels in full patient geometries, representing the dose distribution of a brachytherapy source at a single dwell position using MC simulations and the Geant4 toolkit. These dose kernels are used by the inverse planning by simulated annealing tool to produce a fast MC-based plan. A test was performed for an interstitial brachytherapy breast treatment using two different high-dose-rate brachytherapy sources: the microSelectron iridium-192 source and the electronic brachytherapy source Axxent operating at 50 kVp. A research version of the inverse planning by simulated annealing algorithm was combined with MC to provide a method to fully account for the heterogeneities in dose optimization, using the MC method. The effect of the water approximation was found to depend on photon energy, with greater dose attenuation for the lower energies of the Axxent source compared with iridium-192. For the latter, an underdosage of 5.1% for the dose received by 90% of the clinical target volume was found. A new method to optimize afterloading brachytherapy plans that uses MC dosimetric information was developed. Including computed tomography-based information in MC dosimetry in the inverse planning process was shown to take into account the full range of scatter and heterogeneity conditions. This led to significant dose differences compared with the Task Group report 43 approach for the Axxent source. Copyright © 2011 Elsevier Inc. All rights reserved.

Long-term outcomes in younger men following permanent prostate brachytherapy.

PubMed

Shapiro, Edan Y; Rais-Bahrami, Soroush; Morgenstern, Carol; Napolitano, Barbara; Richstone, Lee; Potters, Louis

2009-04-01

We reviewed the long-term outcomes in men undergoing permanent prostate brachytherapy with a focus on those presenting before age 60 years. Between 1992 and 2005 a total of 2,119 patients with clinical stage T1-T2, N0, M0 prostate cancer treated with permanent prostate brachytherapy were included in this study. Treatment regimens consisted of permanent prostate brachytherapy with or without hormone therapy, permanent prostate brachytherapy with external beam radiotherapy, or all 3 modalities. Biochemical recurrence was defined using the Phoenix definition. Multivariate analysis was performed to determine if age and/or other clinicopathological features were associated with disease progression. The Kaplan-Meier method was used to calculate rates of freedom from progression with the log rank test to compare patients younger than 60 vs 60 years or older. Median followup was 56.1 months. In the study population 237 patients were younger than 60 years at diagnosis (11%). The 5 and 10-year freedom from progression rates were 90.1% and 85.6%, respectively, for the entire population. Multivariate analysis demonstrated that prostate specific antigen (p <0.01), biopsy Gleason score (p <0.0001) and year of treatment (p <0.001) were associated with freedom from progression while age (p = 0.95) and clinical stage (p = 0.11) were not. There was no significant difference in freedom from progression between men younger than 60, or 60 years or older (log rank p = 0.46). In the younger cohort the 10-year freedom from progression for patients presenting with low, intermediate and high risk disease was 91.3%, 80.0% and 70.2% compared to 91.8%, 83.4% and 72.1%, respectively, for men 60 years or older. Our long-term results confirm favorable outcomes after permanent prostate brachytherapy in men younger than 60 years. Outcomes are impacted by disease related risk factors but not by age or clinical stage. Definitive treatment options for younger men with clinically localized prostate cancer should include permanent prostate brachytherapy.

SU-F-BRA-04: Prostate HDR Brachytherapy with Multichannel Robotic System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joseph, F Maria; Podder, T; Yu, Y

Purpose: High-dose-rate (HDR) brachytherapy is gradually becoming popular in treating patients with prostate cancers. However, placement of the HDR needles at desired locations into the patient is challenging. Application of robotic system may improve the accuracy of the clinical procedure. This experimental study is to evaluate the feasibility of using a multichannel robotic system for prostate HDR brachytherapy. Methods: In this experimental study, the robotic system employed was a 6-DOF Multichannel Image-guided Robotic Assistant for Brachytherapy (MIRAB), which was designed and fabricated for prostate seed implantation. The MIRAB has the provision of rotating 16 needles while inserting them. Ten prostatemore » HDR brachytherapy needles were simultaneously inserted using MIRAB into a commercially available prostate phantom. After inserting the needles into the prostate phantom at desired locations, 2mm thick CT slices were obtained for dosimetric planning. HDR plan was generated using Oncetra planning system with a total prescription dose of 34Gy in 4 fractions. Plan quality was evaluated considering dose coverage to prostate and planning target volume (PTV), with 3mm margin around prostate, as well as the dose limit to the organs at risk (OARs) following the American Brachytherapy Society (ABS) guidelines. Results: From the CT scan, it is observed that the needles were inserted straight into the desired locations and they were adequately spaced and distributed for a clinically acceptable HDR plan. Coverage to PTV and prostate were about 91% (V100= 91%) and 96% (V100=96%), respectively. Dose to 1cc of urethra, rectum, and bladder were within the ABS specified limits. Conclusion: The MIRAB was able to insert multiple needles simultaneously into the prostate precisely. By controlling the MIRAB to insert all the ten utilized needles into the prostate phantom, we could achieve the robotic HDR brachytherapy successfully. Further study for assessing the system’s performance and reliability is in progress.« less

Brachytherapy Combined With Surgery for Conservative Treatment of Children With Bladder Neck and/or Prostate Rhabdomyosarcoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chargari, Cyrus, E-mail: cyrus.chargari@gustaveroussy.fr; Institut de Recherche Biomédicale des Armées, Bretigny-sur-Orge; French Military Health Service Academy, Ecole du Val-de-Grâce, Paris

Purpose: To report the results of a conservative strategy based on partial surgery combined with brachytherapy in a prospective cohort of children with bladder–prostate rhabdomyosarcoma (BP RMS). Methods and Materials: We prospectively documented the outcome of children treated in our department between 1991 and 2015 for BP RMS and undergoing a multimodal approach combining conservative surgery (partial cystectomy and/or partial prostatectomy) and perioperative interstitial low-dose-rate or pulse-dose-rate brachytherapy. Before brachytherapy, children had received chemotherapy with modalities depending on their risk group of treatment. Results: A total of 100 patients were identified, with a median age of 28 months (range, 5.6 months-14more » years). According to the Intergroup Rhabdomyosarcoma Study (IRS) group, 84 were IRS-III, and 12 were IRS-IV tumors. Four patients were treated at relapse. The median number of chemotherapy cycles before local therapy was 6 (range, 4-13). After surgery, 63 patients had a macroscopic tumor residuum. Five patients underwent a brachytherapy boost before pelvic external beam radiation therapy because of nodal involvement, and 95 had exclusive brachytherapy. Median follow-up was 64 months (range, 6 months-24.5 years). Five-year disease-free and overall survival rates were 84% (95% confidence interval 80%-88%) and 91% (95% confidence interval 87%-95%), respectively. At last follow-up most survivors presented with only mild to moderate genitourinary sequelae and a normal diurnal urinary continence. Five patients required a secondary total cystectomy: 3 for a nonfunctional bladder and 2 for relapse. Conclusion: Brachytherapy is effective as part of a conservative strategy for BP RMS, with a relatively low delayed toxicity as compared with previously published studies using external beam radiation therapy. Longer follow-up is required to ensure that the functional results are maintained over time.« less

A Real-Time Safety and Quality Reporting System: Assessment of Clinical Data and Staff Participation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahn, Douglas A.; Kim, Gwe-Ya; Mundt, Arno J.

Purpose: To report on the use of an incident learning system in a radiation oncology clinic, along with a review of staff participation. Methods and Materials: On September 24, 2010, our department initiated an online real-time voluntary reporting system for safety issues, called the Radiation Oncology Quality Reporting System (ROQRS). We reviewed these reports from the program's inception through January 18, 2013 (2 years, 3 months, 25 days) to assess error reports (defined as both near-misses and incidents of inaccurate treatment). Results: During the study interval, there were 60,168 fractions of external beam radiation therapy and 955 brachytherapy procedures. There were 298 entriesmore » in the ROQRS system, among which 108 errors were reported. There were 31 patients with near-misses reported and 27 patients with incidents of inaccurate treatment reported. These incidents of inaccurate treatment occurred in 68 total treatment fractions (0.11% of treatments delivered during the study interval). None of these incidents of inaccurate treatment resulted in deviation from the prescription by 5% or more. A solution to the errors was documented in ROQRS in 65% of the cases. Errors occurred as repeated errors in 22% of the cases. A disproportionate number of the incidents of inaccurate treatment were due to improper patient setup at the linear accelerator (P<.001). Physician participation in ROQRS was nonexistent initially, but improved after an education program. Conclusions: Incident learning systems are a useful and practical means of improving safety and quality in patient care.« less

Local Failure After Episcleral Brachytherapy for Posterior Uveal Melanoma: Patterns, Risk Factors, and Management.

PubMed

Bellerive, Claudine; Aziz, Hassan A; Bena, James; Wilkinson, Allan; Suh, John H; Plesec, Thomas; Singh, Arun D

2017-05-01

To evaluate the patterns, the risk factors, and the management of recurrence following brachytherapy in patients with posterior uveal melanoma, given that an understanding of the recurrence patterns can improve early recognition and management of local treatment failure in such patients. Retrospective cohort study. Setting: Multispecialty tertiary care center. A total of 375 eyes treated with episcleral brachytherapy for posterior uveal melanoma from January 2004 to December 2014. Exclusion criteria included inadequate follow-up (<1 year) and previous radiation therapy. Main Outcomes and Measures: Local control rate and time to recurrence were the primary endpoints. Kaplan-Meier estimation and Cox proportional hazards models were conducted to identify risk factors for recurrence. Twenty-one patients (5.6%) experienced recurrence (follow-up range 12-156 months; median 47 months). The median time to recurrence was 18 months (range 4-156 months). Five-year estimated local recurrence rate was 6.6%. The majority (90.5%) of the recurrences occurred within the first 5 years. The predominant site of recurrence was at the tumor margin (12 patients, 57.1%). Univariate analysis identified 3 statistically significant recurrence risk factors: advanced age, largest basal diameter, and the use of adjuvant transpupillary thermotherapy (TTT). Recurrent tumors were managed by repeat brachytherapy, TTT, or enucleation. Local recurrences following brachytherapy are uncommon 5 years after episcleral brachytherapy. Follow-up intervals can be adjusted to reflect time to recurrence. Most of the eyes with recurrent tumor can be salvaged by conservative methods. Copyright © 2017 Elsevier Inc. All rights reserved.

Prostate Brachytherapy Case Volumes by Academic and Nonacademic Practices: Implications for Future Residency Training

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orio, Peter F., E-mail: PORIO@lroc.harvard.edu; Harvard Medical School, Boston, Massachusetts; Nguyen, Paul L.

Purpose: The use of prostate brachytherapy has continued to decline in the United States. We examined the national practice patterns of both academic and nonacademic practices performing prostate brachytherapy by case volume per year to further characterize the decline and postulate the effect this trend might have on training the next generation of residents. Methods and Materials: Men diagnosed with prostate cancer who had undergone radiation therapy in 2004 to 2012 were identified. The annual brachytherapy case volume at each facility was determined and further categorized into ≤12 cases per year (ie, an average of ≤1 cases per month), 13more » to 52 cases per year, and ≥53 cases per year (ie, an average of ≥1 cases per week) in academic practices versus nonacademic practices. Results: In 2004 to 2012, academic practices performing an average of ≤1 brachytherapy cases per month increased from 56.4% to 73.7%. In nonacademic practices, this percentage increased from 60.2% to 77.4% (P<.0001 for both). Practices performing an average of ≥1 cases per week decreased among both academic practices (from 6.7% to 1.5%) and nonacademic practices (from 4.5% to 2.7%). Conclusions: Both academic and nonacademic radiation oncology practices have demonstrated a significant reduction in the use of prostate brachytherapy from 2004 to 2012. With the case volume continuing to decline, it is unclear whether we are prepared to train the next generation of residents in this critical modality.« less

18 years' experience with high dose rate strontium-90 brachytherapy of small to medium sized posterior uveal melanoma.

PubMed

van Ginderdeuren, R; van Limbergen, E; Spileers, W

2005-10-01

To analyse local tumour control, radiation related complications, visual acuity, enucleation rate, and survival after brachytherapy of small to medium sized choroidal melanoma (CM) with a high dose rate (HDR) strontium-90 (Sr-90) applicator. From 1983 until 2000, 98 eyes with CM were treated with Sr-90 brachytherapy. The main outcome measures were actuarial rates of the patients' survival, ocular conservation rate, tumour regression, complication rates, and preservation of visual acuity. End point rates were estimated using Kaplan-Meier analysis. The median follow up time was 6.7 years (0.5-18.8 years). Actuarial melanoma free patient survival rate was 85% (SE 4.8%) after 18 years. Actuarial rate of ocular conservation and complete tumour regression was 90% (SE 3.8%) after 15 years. In 93% local tumour control was achieved, 88% showed a stable scar. Recurrence of the tumour on the border caused enucleation of six eyes (7%). In three cases (4%) retinal detachment was the end point. No cases of optic atrophy or of sight impairing retinopathy outside the treated area were found. Actuarial rate of preservation of visual acuity of 1/10 was 65% at 5 years and 45% at 15 years of follow up (SE 5.9% and 8.8%). Sr-90 brachytherapy is as effective as iodine or ruthenium brachytherapy for small to medium sized CM but causes fewer complications. The preservation of vision is better than with all other described radioisotopes. HDR Sr-90 brachytherapy can therefore safely be recommended for small to medium sized CM.

18 Years’ experience with high dose rate strontium-90 brachytherapy of small to medium sized posterior uveal melanoma

PubMed Central

van Ginderdeuren, R; van Limbergen, E; Spileers, W

2005-01-01

Aim: To analyse local tumour control, radiation related complications, visual acuity, enucleation rate, and survival after brachytherapy of small to medium sized choroidal melanoma (CM) with a high dose rate (HDR) strontium-90 (Sr-90) applicator. Methods: From 1983 until 2000, 98 eyes with CM were treated with Sr-90 brachytherapy. The main outcome measures were actuarial rates of the patients’ survival, ocular conservation rate, tumour regression, complication rates, and preservation of visual acuity. End point rates were estimated using Kaplan-Meier analysis. Results: The median follow up time was 6.7 years (0.5–18.8 years). Actuarial melanoma free patient survival rate was 85% (SE 4.8%) after 18 years. Actuarial rate of ocular conservation and complete tumour regression was 90% (SE 3.8%) after 15 years. In 93% local tumour control was achieved, 88% showed a stable scar. Recurrence of the tumour on the border caused enucleation of six eyes (7%). In three cases (4%) retinal detachment was the end point. No cases of optic atrophy or of sight impairing retinopathy outside the treated area were found. Actuarial rate of preservation of visual acuity of 1/10 was 65% at 5 years and 45% at 15 years of follow up (SE 5.9% and 8.8%). Conclusions: Sr-90 brachytherapy is as effective as iodine or ruthenium brachytherapy for small to medium sized CM but causes fewer complications. The preservation of vision is better than with all other described radioisotopes. HDR Sr-90 brachytherapy can therefore safely be recommended for small to medium sized CM. PMID:16170122

MO-D-BRD-03: Radiobiology and Commissioning of Electronic Brachytherapy for IORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, J.

2015-06-15

Electronic brachytherapy (eBT) has seen an insurgence of manufacturers entering the US market for use in radiation therapy. In addition to the established interstitial, intraluminary, and intracavitary applications of eBT, many centers are now using eBT to treat skin lesions. It is important for medical physicists working with electronic brachytherapy sources to understand the basic physics principles of the sources themselves as well as the variety of applications for which they are being used. The calibration of the sources is different from vendor to vendor and the traceability of calibrations has evolved as new sources came to market. In 2014,more » a new air-kerma based standard was introduced by the National Institute of Standards and Technology (NIST) to measure the output of an eBT source. Eventually commercial treatment planning systems should accommodate this new standard and provide NIST traceability to the end user. The calibration and commissioning of an eBT system is unique to its application and typically entails a list of procedural recommendations by the manufacturer. Commissioning measurements are performed using a variety of methods, some of which are modifications of existing AAPM Task Group protocols. A medical physicist should be familiar with the different AAPM Task Group recommendations for applicability to eBT and how to properly adapt them to their needs. In addition to the physical characteristics of an eBT source, the photon energy is substantially lower than from HDR Ir-192 sources. Consequently, tissue-specific dosimetry and radiobiological considerations are necessary when comparing these brachytherapy modalities and when making clinical decisions as a radiation therapy team. In this session, the physical characteristics and calibration methodologies of eBt sources will be presented as well as radiobiology considerations and other important clinical considerations. Learning Objectives: To understand the basic principles of electronic brachytherapy and the various applications for which it is being used. To understand the physics of the calibration and commissioning for electronic brachytherapy sources To understand the unique radiobiology and clinical implementation of electronic brachytherapy systems for skin and IORT techniques Xoft, Inc. contributed funding toward development of the NIST electronic brachytherapy facility (Michael Mitch).The University of Wisconsin (Wesley Culberson) has received research support funding from Xoft, Inc. Zoubir Ouhib has received partial funding from Elekta Esteya.« less

MO-D-BRD-01: Clinical Implementation of An Electronic Brachytherapy Program for the Skin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ouhib, Z.

2015-06-15

Electronic brachytherapy (eBT) has seen an insurgence of manufacturers entering the US market for use in radiation therapy. In addition to the established interstitial, intraluminary, and intracavitary applications of eBT, many centers are now using eBT to treat skin lesions. It is important for medical physicists working with electronic brachytherapy sources to understand the basic physics principles of the sources themselves as well as the variety of applications for which they are being used. The calibration of the sources is different from vendor to vendor and the traceability of calibrations has evolved as new sources came to market. In 2014,more » a new air-kerma based standard was introduced by the National Institute of Standards and Technology (NIST) to measure the output of an eBT source. Eventually commercial treatment planning systems should accommodate this new standard and provide NIST traceability to the end user. The calibration and commissioning of an eBT system is unique to its application and typically entails a list of procedural recommendations by the manufacturer. Commissioning measurements are performed using a variety of methods, some of which are modifications of existing AAPM Task Group protocols. A medical physicist should be familiar with the different AAPM Task Group recommendations for applicability to eBT and how to properly adapt them to their needs. In addition to the physical characteristics of an eBT source, the photon energy is substantially lower than from HDR Ir-192 sources. Consequently, tissue-specific dosimetry and radiobiological considerations are necessary when comparing these brachytherapy modalities and when making clinical decisions as a radiation therapy team. In this session, the physical characteristics and calibration methodologies of eBt sources will be presented as well as radiobiology considerations and other important clinical considerations. Learning Objectives: To understand the basic principles of electronic brachytherapy and the various applications for which it is being used. To understand the physics of the calibration and commissioning for electronic brachytherapy sources To understand the unique radiobiology and clinical implementation of electronic brachytherapy systems for skin and IORT techniques Xoft, Inc. contributed funding toward development of the NIST electronic brachytherapy facility (Michael Mitch).The University of Wisconsin (Wesley Culberson) has received research support funding from Xoft, Inc. Zoubir Ouhib has received partial funding from Elekta Esteya.« less

MO-D-BRD-04: NIST Air-Kerma Standard for Electronic Brachytherapy Calibrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitch, M.

Electronic brachytherapy (eBT) has seen an insurgence of manufacturers entering the US market for use in radiation therapy. In addition to the established interstitial, intraluminary, and intracavitary applications of eBT, many centers are now using eBT to treat skin lesions. It is important for medical physicists working with electronic brachytherapy sources to understand the basic physics principles of the sources themselves as well as the variety of applications for which they are being used. The calibration of the sources is different from vendor to vendor and the traceability of calibrations has evolved as new sources came to market. In 2014,more » a new air-kerma based standard was introduced by the National Institute of Standards and Technology (NIST) to measure the output of an eBT source. Eventually commercial treatment planning systems should accommodate this new standard and provide NIST traceability to the end user. The calibration and commissioning of an eBT system is unique to its application and typically entails a list of procedural recommendations by the manufacturer. Commissioning measurements are performed using a variety of methods, some of which are modifications of existing AAPM Task Group protocols. A medical physicist should be familiar with the different AAPM Task Group recommendations for applicability to eBT and how to properly adapt them to their needs. In addition to the physical characteristics of an eBT source, the photon energy is substantially lower than from HDR Ir-192 sources. Consequently, tissue-specific dosimetry and radiobiological considerations are necessary when comparing these brachytherapy modalities and when making clinical decisions as a radiation therapy team. In this session, the physical characteristics and calibration methodologies of eBt sources will be presented as well as radiobiology considerations and other important clinical considerations. Learning Objectives: To understand the basic principles of electronic brachytherapy and the various applications for which it is being used. To understand the physics of the calibration and commissioning for electronic brachytherapy sources To understand the unique radiobiology and clinical implementation of electronic brachytherapy systems for skin and IORT techniques Xoft, Inc. contributed funding toward development of the NIST electronic brachytherapy facility (Michael Mitch).The University of Wisconsin (Wesley Culberson) has received research support funding from Xoft, Inc. Zoubir Ouhib has received partial funding from Elekta Esteya.« less

MO-D-BRD-00: Electronic Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Electronic brachytherapy (eBT) has seen an insurgence of manufacturers entering the US market for use in radiation therapy. In addition to the established interstitial, intraluminary, and intracavitary applications of eBT, many centers are now using eBT to treat skin lesions. It is important for medical physicists working with electronic brachytherapy sources to understand the basic physics principles of the sources themselves as well as the variety of applications for which they are being used. The calibration of the sources is different from vendor to vendor and the traceability of calibrations has evolved as new sources came to market. In 2014,more » a new air-kerma based standard was introduced by the National Institute of Standards and Technology (NIST) to measure the output of an eBT source. Eventually commercial treatment planning systems should accommodate this new standard and provide NIST traceability to the end user. The calibration and commissioning of an eBT system is unique to its application and typically entails a list of procedural recommendations by the manufacturer. Commissioning measurements are performed using a variety of methods, some of which are modifications of existing AAPM Task Group protocols. A medical physicist should be familiar with the different AAPM Task Group recommendations for applicability to eBT and how to properly adapt them to their needs. In addition to the physical characteristics of an eBT source, the photon energy is substantially lower than from HDR Ir-192 sources. Consequently, tissue-specific dosimetry and radiobiological considerations are necessary when comparing these brachytherapy modalities and when making clinical decisions as a radiation therapy team. In this session, the physical characteristics and calibration methodologies of eBt sources will be presented as well as radiobiology considerations and other important clinical considerations. Learning Objectives: To understand the basic principles of electronic brachytherapy and the various applications for which it is being used. To understand the physics of the calibration and commissioning for electronic brachytherapy sources To understand the unique radiobiology and clinical implementation of electronic brachytherapy systems for skin and IORT techniques Xoft, Inc. contributed funding toward development of the NIST electronic brachytherapy facility (Michael Mitch).The University of Wisconsin (Wesley Culberson) has received research support funding from Xoft, Inc. Zoubir Ouhib has received partial funding from Elekta Esteya.« less

MO-D-BRD-02: Radiological Physics and Surface Lesion Treatments with Electronic Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fulkerson, R.

Electronic brachytherapy (eBT) has seen an insurgence of manufacturers entering the US market for use in radiation therapy. In addition to the established interstitial, intraluminary, and intracavitary applications of eBT, many centers are now using eBT to treat skin lesions. It is important for medical physicists working with electronic brachytherapy sources to understand the basic physics principles of the sources themselves as well as the variety of applications for which they are being used. The calibration of the sources is different from vendor to vendor and the traceability of calibrations has evolved as new sources came to market. In 2014,more » a new air-kerma based standard was introduced by the National Institute of Standards and Technology (NIST) to measure the output of an eBT source. Eventually commercial treatment planning systems should accommodate this new standard and provide NIST traceability to the end user. The calibration and commissioning of an eBT system is unique to its application and typically entails a list of procedural recommendations by the manufacturer. Commissioning measurements are performed using a variety of methods, some of which are modifications of existing AAPM Task Group protocols. A medical physicist should be familiar with the different AAPM Task Group recommendations for applicability to eBT and how to properly adapt them to their needs. In addition to the physical characteristics of an eBT source, the photon energy is substantially lower than from HDR Ir-192 sources. Consequently, tissue-specific dosimetry and radiobiological considerations are necessary when comparing these brachytherapy modalities and when making clinical decisions as a radiation therapy team. In this session, the physical characteristics and calibration methodologies of eBt sources will be presented as well as radiobiology considerations and other important clinical considerations. Learning Objectives: To understand the basic principles of electronic brachytherapy and the various applications for which it is being used. To understand the physics of the calibration and commissioning for electronic brachytherapy sources To understand the unique radiobiology and clinical implementation of electronic brachytherapy systems for skin and IORT techniques Xoft, Inc. contributed funding toward development of the NIST electronic brachytherapy facility (Michael Mitch).The University of Wisconsin (Wesley Culberson) has received research support funding from Xoft, Inc. Zoubir Ouhib has received partial funding from Elekta Esteya.« less

Integrated transrectal probe for translational ultrasound-photoacoustic imaging

NASA Astrophysics Data System (ADS)

Bell, Kevan L.; Harrison, Tyler; Usmani, Nawaid; Zemp, Roger J.

2016-03-01

A compact photoacoustic transrectal probe is constructed for improved imaging in brachytherapy treatment. A 192 element 5 MHz linear transducer array is mounted inside a small 3D printed casing along with an array of optical fibers. The device is fed by a pump laser and tunable NIR-optical parametric oscillator with data collected by a Verasonics ultrasound platform. This assembly demonstrates improved imaging of brachytherapy seeds in phantoms with depths up to 5 cm. The tuneable excitation in combination with standard US integration provides adjustable contrast between the brachytherapy seeds, blood filled tubes and background tissue.

Adjuvant vaginal brachytherapy as a part of management in early endometrial cancer.

PubMed

Kellas-Ślęczka, Sylwia; Wojcieszek, Piotr; Białas, Brygida

2012-12-01

Endometrial cancer is the most frequent cancer of female genital tract. Metro- and menorrhagia or postmenopausal bleeding results in its early presentation. It allows radical treatment. However, controversies remain on surgery coverage or adjuvant therapies in early endometrial women cancer. Optimal management should minimize intervention instead of aggressive approach, as showed by recent studies. There is a role for brachytherapy as an adjuvant irradiation. Crucial publications including PORTEC-1, GOG 99, MRC ASTEC, ASTEC/EN.5, PORTEC-2 or Italian lymphadenectomy trial are discussed. Moreover, there is attention paid on adjuvant vaginal brachytherapy analyses for the past fifteen years.

Implementation of image-guided brachytherapy (IGBT) for patients with uterine cervix cancer: a tumor volume kinetics approach.

PubMed

Carvalho, Heloisa de Andrade; Mendez, Lucas Castro; Stuart, Silvia Radwanski; Guimarães, Roger Guilherme Rodrigues; Ramos, Clarissa Cerchi Angotti; de Paula, Lucas Assad; de Sales, Camila Pessoa; Chen, André Tsin Chih; Blasbalg, Roberto; Baroni, Ronaldo Hueb

2016-08-01

To evaluate tumor shrinking kinetics in order to implement image-guided brachytherapy (IGBT) for the treatment of patients with cervix cancer. This study has prospectively evaluated tumor shrinking kinetics of thirteen patients with uterine cervix cancer treated with combined chemoradiation. Four high dose rate brachytherapy fractions were delivered during the course of pelvic external beam radiation therapy (EBRT). Magnetic resonance imaging (MRI) exams were acquired at diagnosis (D), first (B1), and third (B3) brachytherapy fractions. Target volumes (GTV and HR-CTV) were calculated by both the ellipsoid formula (VE) and MRI contouring (VC), which were defined by a consensus between at least two radiation oncologists and a pelvic expert radiologist. Most enrolled patients had squamous cell carcinoma and FIGO stage IIB disease, and initiated brachytherapy after the third week of pelvic external beam radiation. Gross tumor volume volume reduction from diagnostic MRI to B1 represented 61.9% and 75.2% of the initial volume, when measured by VE and VC, respectively. Only a modest volume reduction (15-20%) was observed from B1 to B3. The most expressive tumor shrinking occurred in the first three weeks of oncological treatment and was in accordance with gynecological examination. These findings may help in IGBT implementation.

Photoacoustic imaging of prostate brachytherapy seeds with transurethral light delivery

NASA Astrophysics Data System (ADS)

Lediju Bell, Muyinatu A.; Guo, Xiaoyu; Song, Danny Y.; Boctor, Emad M.

2014-03-01

We present a novel approach to photoacoustic imaging of prostate brachytherapy seeds utilizing an existing urinary catheter for transurethral light delivery. Two canine prostates were surgically implanted with brachyther- apy seeds under transrectal ultrasound guidance. One prostate was excised shortly after euthanasia and fixed in gelatin. The second prostate was imaged in the native tissue environment shortly after euthanasia. A urinary catheter was inserted in the urethra of each prostate. A 1-mm core diameter optical fiber coupled to a 1064 nm Nd:YAG laser was inserted into the urinary catheter. Light from the fiber was either directed mostly parallel to the fiber axis (i.e. end-fire fire) or mostly 90° to the fiber axis (i.e. side-fire fiber). An Ultrasonix SonixTouch scanner, transrectal ultrasound probe with curvilinear (BPC8-4) and linear (BPL9-5) arrays, and DAQ unit were utilized for synchronized laser light emission and photoacoustic signal acquisition. The implanted brachytherapy seeds were visualized at radial distances of 6-16 mm from the catheter. Multiple brachytherapy seeds were si- multaneously visualized with each array of the transrectal probe using both delay-and-sum (DAS) and short-lag spatial coherence (SLSC) beamforming. This work is the first to demonstrate the feasibility of photoacoustic imaging of prostate brachytherapy seeds using a transurethral light delivery method.

Implantable chemothermal brachytherapy seeds: A synergistic approach to brachytherapy using polymeric dual drug delivery and hyperthermia for malignant solid tumor ablation.

PubMed

Aguilar, Ludwig Erik; Thomas, Reju George; Moon, Myeong Ju; Jeong, Yong Yeon; Park, Chan Hee; Kim, Cheol Sang

2018-08-01

Chemothermal brachytherapy seeds have been developed using a combination of polymeric dual drug chemotherapy and alternating magnetic field induced hyperthermia. The synergistic effect of chemotherapy and hyperthermia brachytherapy has been investigated in a way that has never been performed before, with an in-depth analysis of the cancer cell inhibition property of the new system. A comprehensive in vivo study on athymic mice model with SCC7 tumor has been conducted to determine optimal arrays and specifications of the chemothermal seeds. Dual drug chemotherapy has been achieved via surface deposition of polydopamine that carries bortezomib, and also via loading an acidic pH soluble hydrogel that contains 5-Fluorouracil inside the chemothermal seed; this increases the drug loading capacity of the chemothermal seed, and creates dual drug synergism. An external alternating magnetic field has been utilized to induce hyperthermia conditions, using the inherent ferromagnetic property of the nitinol alloy used as the seed casing. The materials used in this study were fully characterized using FESEM, H 1 NMR, FT-IR, and XPS to validate their properties. This new approach to experimental cancer treatment is a pilot study that exhibits the potential of thermal brachytherapy and chemotherapy as a combined treatment modality. Copyright © 2018 Elsevier B.V. All rights reserved.

A case-cohort study of recurrent salivary adenoid cystic carcinoma after iodine 125 brachytherapy and resection treatment.

PubMed

Li, Bin-bin; Xie, Xiao-Yan; Jia, Sheng-Nan

2015-02-01

Recurrent adenoid cystic carcinoma (rAdCC) can be challenging to be treated with brachytherapy, although brachytherapy is safe and effective in treating head and neck cancers. Patients of adenoid cystic carcinoma (AdCC), who underwent resection and iodine 125 ((125)I) radioactive seed implantation, were recruited for this study. Clinical data, surgical details of resection and seed implantation, histologic characteristics, and prognosis were studied. There were 16 rAdCC cases among 140 cases of AdCC treated with brachytherapy and resection. The mean follow-up duration for the recurrent cases was 61 months. The 3-year local control rate of rAdCC was 51.6%, and the overall disease-specific survival rate was 49.4%. Eight patients showed distant metastasis (50%, 8/16). The histologic grades of 10 rAdCCs were upgraded (62.5%, 10/16).Two cases displayed sarcomatous transformation after brachytherapy (1.4%, 2/140). Although the overall local control rate and survival rate were relatively favorable, some rAdCCs with an aggressive phenotype appeared to respond poorly to (125)I seed implantation. Preventive adjuvant chemotherapy should be prescribed for these rAdCCs. Copyright © 2014 Elsevier Inc. All rights reserved.

One-year results from clinical practice of epimacular strontium-90 brachytherapy for the treatment of subfoveal choroidal neovascularization secondary to AMD.

PubMed

Zur, Dinah; Loewenstein, Anat; Barak, Adiel

2015-03-01

To evaluate clinical feasibility, safety, and efficacy of epiretinal strontium-90 brachytherapy in subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration (AMD) in eyes unresponsive to repeated anti-VEGF injections. A retrospective, single-center study on patients treated with strontium-90 brachytherapy for CNV secondary to neovascular AMD. Patients underwent pars plana vitrectomy with a single 24 Gy dose brachytherapy. They were re-treated with anti-VEGF injections on an as-needed basis if subretinal or intraretinal fluid was detected on optical coherence tomography imaging. Twenty-two patients were treated, and 20 completed 12 months of follow-up. Ten patients maintained stable vision, eight gained vision, and two lost more than three Snellen lines. The mean best corrected visual acuity change from baseline was -8 ± 5.7 letters. A mean of 5.5 ± 4.4 anti-VEGF injections were administered throughout 12 months. Epimacular brachytherapy is feasible in clinical practice. While some patients benefit from the treatment and need significantly fewer as-needed injections, others appear not to react to irradiation treatment after 1 year of follow-up. Larger numbers of patients are needed to evaluate therapeutic efficacy and to determine which patients can benefit from combined radiation and anti-VEGF therapy. Copyright 2015, SLACK Incorporated.

The evolution of brachytherapy for prostate cancer.

PubMed

Zaorsky, Nicholas G; Davis, Brian J; Nguyen, Paul L; Showalter, Timothy N; Hoskin, Peter J; Yoshioka, Yasuo; Morton, Gerard C; Horwitz, Eric M

2017-06-30

Brachytherapy (BT), using low-dose-rate (LDR) permanent seed implantation or high-dose-rate (HDR) temporary source implantation, is an acceptable treatment option for select patients with prostate cancer of any risk group. The benefits of HDR-BT over LDR-BT include the ability to use the same source for other cancers, lower operator dependence, and - typically - fewer acute irritative symptoms. By contrast, the benefits of LDR-BT include more favourable scheduling logistics, lower initial capital equipment costs, no need for a shielded room, completion in a single implant, and more robust data from clinical trials. Prospective reports comparing HDR-BT and LDR-BT to each other or to other treatment options (such as external beam radiotherapy (EBRT) or surgery) suggest similar outcomes. The 5-year freedom from biochemical failure rates for patients with low-risk, intermediate-risk, and high-risk disease are >85%, 69-97%, and 63-80%, respectively. Brachytherapy with EBRT (versus brachytherapy alone) is an appropriate approach in select patients with intermediate-risk and high-risk disease. The 10-year rates of overall survival, distant metastasis, and cancer-specific mortality are >85%, <10%, and <5%, respectively. Grade 3-4 toxicities associated with HDR-BT and LDR-BT are rare, at <4% in most series, and quality of life is improved in patients who receive brachytherapy compared with those who undergo surgery.

Calculated and measured brachytherapy dosimetry parameters in water for the Xoft Axxent X-Ray Source: an electronic brachytherapy source.

PubMed

Rivard, Mark J; Davis, Stephen D; DeWerd, Larry A; Rusch, Thomas W; Axelrod, Steve

2006-11-01

A new x-ray source, the model S700 Axxent X-Ray Source (Source), has been developed by Xoft Inc. for electronic brachytherapy. Unlike brachytherapy sources containing radionuclides, this Source may be turned on and off at will and may be operated at variable currents and voltages to change the dose rate and penetration properties. The in-water dosimetry parameters for this electronic brachytherapy source have been determined from measurements and calculations at 40, 45, and 50 kV settings. Monte Carlo simulations of radiation transport utilized the MCNP5 code and the EPDL97-based mcplib04 cross-section library. Inter-tube consistency was assessed for 20 different Sources, measured with a PTW 34013 ionization chamber. As the Source is intended to be used for a maximum of ten treatment fractions, tube stability was also assessed. Photon spectra were measured using a high-purity germanium (HPGe) detector, and calculated using MCNP. Parameters used in the two-dimensional (2D) brachytherapy dosimetry formalism were determined. While the Source was characterized as a point due to the small anode size, < 1 mm, use of the one-dimensional (1D) brachytherapy dosimetry formalism is not recommended due to polar anisotropy. Consequently, 1D brachytherapy dosimetry parameters were not sought. Calculated point-source model radial dose functions at gP(5) were 0.20, 0.24, and 0.29 for the 40, 45, and 50 kV voltage settings, respectively. For 1

SU-E-T-171: Characterization of the New Xoft Axxent Electronic Brachytherapy Source Using PRESAGE Dosimeters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinmann, A; Followill, D; Ibbott, G

Purpose: To characterize the Xoft Axxent electronic brachytherapy source using PRESAGE™ dosimeters to obtain independent confirmation of TG-43U1 dosimetry values from previous studies and ascertain its reproducibility in HDR brachytherapy. Methods: PRESAGE™ dosimeters are solid, polyurethane-based dosimeters doped with radiochromic leucodyes that produce a linear optical-density response when exposed to radiation. Eight 1-kg dosimeters were scanned prior to irradiation on an optical-CT scanner to eliminate background signal and any optical imperfections from each dosimeter. To quantify potential imaging artifacts due to oversaturated responses in the immediate range of the source, half of the eight dosimeters were cast with a smallermore » channel diameter of 5.4 mm, and the other half were cast with a larger channel diameter of 15mm. During irradiation, the catheters were placed in the center of each channel. Catheters fit the 5.4mm diameters channels whereas polyurethane plugs were inserted into the larger channels to create a sturdy, immobile catheter which allowed uniform dose distributions. Two dosimeters of each 5.4mm and 15mm were irradiated at either 1517.3 cGy or 2017.5 cGy. Post-irradiation scans were performed within 48 hours of irradiation. A 3D reconstruction based on subtraction of these two images and the relative dose measurements were made using in-house software. Results: Comparing measured radial dose rates with previous results revealed smaller percent errors when PRESAGE™ irradiations were at lower maximum dose. The dosimeters showed small deviations in radial dose function, g{sub p} (r), from previous studies. Among the dosimeters irradiated at 1517.3 cGy, the g{sub p}(r) compared to previous studies fluctuated from 0.0043 to 0.3922. This suggests small fluctuations can drastically change radial dose calculations. Conclusion: The subtraction of pre-irradiation and post-irradiation scans of PRESAGE™ dosimeters using an optical-CT scanner shows promising results in determining 3D dosimetry for Xoft Axxent devices; however, further research is recommended. NIH Grant#: 5-U24-CA081647-13; ROI Grant#: 5R01CA100835.« less

Medical malpractice of prostate brachytherapy.

PubMed

Elliott, Kathryn; Wallner, Kent; Merrick, Gregory; Herstein, Paul

2004-01-01

To summarize the basis for brachytherapy-associated legal complaints. The cases summarized here were those worked on by one author (KW) from 1992 through 2002. Summary information about cases is kept solely for the purpose of informing opposing counsel regarding past experience as a defendant or expert witness. No information summarized here is kept for medical research purposes. KW was the defendant in three cases, and an expert witness in the remaining 10 cases. Eleven cases were initiated due to a prostatic-rectal fistula--an abnormal communication between the prostatic urethra and rectum formed because of breakdown of irradiated tissue. Of the cases not involving a fistula, one was initiated due to chronic urinary burning, and the other arose from a patient identification mix-up, such that the plaintiff was treated with the implant planned for another patient. The principal physician defendant(s), after pre-trial winnowing, was the radiation oncologist alone in eight cases and the radiation oncologist and the urologist in five cases. In no case was a urologist named as a defendant without the radiation oncologist. None of the eleven rectal fistula cases involved an egregious seed placement error. Instead, plaintiff attorneys typically claimed breach of standard for care for what most physicians would likely consider to be variations within the standard of care. Prostate brachytherapists should brace themselves for the likelihood of more lawsuits. In addition to fistulas, plaintiff attorneys are likely to devise more bases for lawsuits in the future.

Strength estimation of a moving 125Iodine source during implantation in brachytherapy: application to linked sources.

PubMed

Tanaka, Kenichi; Endo, Satoru; Tateoka, Kunihiko; Asanuma, Osamu; Hori, Masakazu; Takagi, Masaru; Bengua, Gerard; Kamo, Ken-Ichi; Sato, Kaori; Takeda, Hiromitsu; Hareyama, Masato; Sakata, Koh-Ichi; Takada, Jun

2014-11-01

This study sought to demonstrate the feasibility of estimating the source strength during implantation in brachytherapy. The requirement for measuring the strengths of the linked sources was investigated. The utilized sources were (125)I with air kerma strengths of 8.38-8.63 U (μGy m(2) h(-1)). Measurements were performed with a plastic scintillator (80 mm × 50 mm × 20 mm in thickness). For a source-to-source distance of 10.5 mm and at source speeds of up to 200 mm s(-1), a counting time of 10 ms and a detector-to-needle distance of 5 mm were found to be the appropriate measurement conditions. The combined standard uncertainty (CSU) with the coverage factor of 1 (k = 1) was ∼15% when using a grid to decrease the interference by the neighboring sources. Without the grid, the CSU (k = 1) was ∼5%, and an 8% overestimation due to the neighboring sources was found to potentially cause additional uncertainty. In order to improve the accuracy in estimating source strength, it is recommended that the measurment conditions should be optimized by considering the tradeoff between the overestimation due to the neighboring sources and the intensity of the measured value, which influences the random error. © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

In vivo dosimetry using a linear Mosfet-array dosimeter to determine the urethra dose in 125I permanent prostate implants.

PubMed

Bloemen-van Gurp, Esther J; Murrer, Lars H P; Haanstra, Björk K C; van Gils, Francis C J M; Dekker, Andre L A J; Mijnheer, Ben J; Lambin, Philippe

2009-01-01

In vivo dosimetry during brachytherapy of the prostate with (125)I seeds is challenging because of the high dose gradients and low photon energies involved. We present the results of a study using metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to evaluate the dose in the urethra after a permanent prostate implantation procedure. Phantom measurements were made to validate the measurement technique, determine the measurement accuracy, and define action levels for clinical measurements. Patient measurements were performed with a MOSFET array in the urinary catheter immediately after the implantation procedure. A CT scan was performed, and dose values, calculated by the treatment planning system, were compared to in vivo dose values measured with MOSFET dosimeters. Corrections for temperature dependence of the MOSFET array response and photon attenuation in the catheter on the in vivo dose values are necessary. The overall uncertainty in the measurement procedure, determined in a simulation experiment, is 8.0% (1 SD). In vivo dose values were obtained for 17 patients. In the high-dose region (> 100 Gy), calculated and measured dose values agreed within 1.7% +/- 10.7% (1 SD). In the low-dose region outside the prostate (< 100 Gy), larger deviations occurred. MOSFET detectors are suitable for in vivo dosimetry during (125)I brachytherapy of prostate cancer. An action level of +/- 16% (2 SD) for detection of errors in the implantation procedure is achievable after validation of the detector system and measurement conditions.

77 FR 68209 - Medicare and Medicaid Programs: Hospital Outpatient Prospective Payment and Ambulatory Surgical...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-15

...-through devices, brachytherapy sources, intraoperative radiation therapy (IORT), brachytherapy composite... Modulated Radiation Therapy I/OCE Integrated Outpatient Code Editor IOL Intraocular lens IOM Institute of Medicine IORT Intraoperative radiation treatment IPF Inpatient Psychiatric Facility IPPS [Hospital...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grant, Stephen R.; Walker, Gary V.; Koshy, Matthew

Purpose: The Patient Protection and Affordable Care Act looks to expand both private and Medicaid insurance. To evaluate how these changes may affect the field of radiation oncology, we evaluated the association of insurance status with the use of brachytherapy in cancers for which this treatment technique is used. Methods and Materials: A total of 190,467 patients met the inclusion criteria, of whom 95,292 (50.0%) had breast cancer, 61,096 (32.1%) had prostate cancer, 28,194 (14.8%) had endometrial cancer, and 5885 (3.1%) had cervical cancer. A multivariate logistic regression model was used to determine the association between insurance status and receiptmore » of brachytherapy among patients treated definitively for prostate and cervical cancer or postoperatively for breast and endometrial cancer. Results: The rates of non-Medicaid insurance were 49.9% (cervical), 85.3% (endometrial), 87.4% (breast), and 90.9% (prostate) (P<.001). In a logistic regression, patients who received radiation therapy were less likely to receive brachytherapy if they had Medicaid coverage (odds ratio [OR] 0.57, 95% confidence interval [CI] 0.53-0.61, P<.001) or did not have insurance coverage (OR 0.50, 95% CI 0.45-0.56, P<.001) compared with those with non-Medicaid insurance. On subset analysis, patients with Medicaid coverage or without insurance coverage were significantly less likely to receive brachytherapy than were those with non-Medicaid insurance for all 4 sites, except for patients with endometrial cancer. Conclusions: Despite being a cost-effective treatment modality, brachytherapy is less often used in the definitive or postoperative management of cancer in patients with Medicaid coverage or without insurance. Upcoming health policy changes resulting in the expansion of private insurance and Medicaid will likely increase access to and demand for brachytherapy.« less

American Brachytherapy Society Task Group Report: Combination of brachytherapy and external beam radiation for high-risk prostate cancer.

PubMed

Spratt, Daniel E; Soni, Payal D; McLaughlin, Patrick W; Merrick, Gregory S; Stock, Richard G; Blasko, John C; Zelefsky, Michael J

To review outcomes for high-risk prostate cancer treated with combined modality radiation therapy (CMRT) utilizing external beam radiation therapy (EBRT) with a brachytherapy boost. The available literature for high-risk prostate cancer treated with combined modality radiation therapy was reviewed and summarized. At this time, the literature suggests that the majority of high-risk cancers are curable with multimodal treatment. Several large retrospective studies and three prospective randomized trials comparing CMRT to dose-escalated EBRT have demonstrated superior biochemical control with CMRT. Longer followup of the randomized trials will be required to determine if this will translate to a benefit in metastasis-free survival, disease-specific survival, and overall survival. Although greater toxicity has been associated with CMRT compared to EBRT, recent studies suggest that technological advances that allow better definition and sparing of critical adjacent structures as well as increasing experience with brachytherapy have improved implant quality and the toxicity profile of brachytherapy. The role of androgen deprivation therapy is well established in the external beam literature for high-risk disease, but there is controversy regarding the applicability of these data in the setting of dose escalation. At this time, there is not sufficient evidence for the omission of androgen deprivation therapy with dose escalation in this population. Comparisons with surgery remain limited by differences in patient selection, but the evidence would suggest better disease control with CMRT compared to surgery alone. Due to a series of technological advances, modern combination series have demonstrated unparalleled rates of disease control in the high-risk population. Given the evidence from recent randomized trials, combination therapy may become the standard of care for high-risk cancers. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Sci-Thur PM – Brachytherapy 01: Fast brachytherapy dose calculations: Characterization of egs-brachy features to enhance simulation efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chamberland, Marc; Taylor, Randle E.P.; Rogers, Da

2016-08-15

Purpose: egs-brachy is a fast, new EGSnrc user-code for brachytherapy applications. This study characterizes egs-brachy features that enhance simulation efficiency. Methods: Calculations are performed to characterize efficiency gains from various features. Simulations include radionuclide and miniature x-ray tube sources in water phantoms and idealized prostate, breast, and eye plaque treatments. Features characterized include voxel indexing of sources to reduce boundary checks during radiation transport, scoring collision kerma via tracklength estimator, recycling photons emitted from sources, and using phase space data to initiate simulations. Bremsstrahlung cross section enhancement (BCSE), uniform bremsstrahlung splitting (UBS), and Russian Roulette (RR) are considered for electronicmore » brachytherapy. Results: Efficiency is enhanced by a factor of up to 300 using tracklength versus interaction scoring of collision kerma and by up to 2.7 and 2.6 using phase space sources and particle recycling respectively compared to simulations in which particles are initiated within sources. On a single 2.5 GHz Intel Xeon E5-2680 processor cor, simulations approximating prostate and breast permanent implant ((2 mm){sup 3} voxels) and eye plaque ((1 mm){sup 3}) treatments take as little as 9 s (prostate, eye) and up to 31 s (breast) to achieve 2% statistical uncertainty on doses within the PTV. For electronic brachytherapy, BCSE, UBS, and RR enhance efficiency by a factor >2000 compared to a factor of >10{sup 4} using a phase space source. Conclusion: egs-brachy features provide substantial efficiency gains, resulting in calculation times sufficiently fast for full Monte Carlo simulations for routine brachytherapy treatment planning.« less

Evidence for the use PET for radiation therapy planning in patients with cervical cancer: a systematic review.

PubMed

Salem, A; Salem, A F; Al-Ibraheem, A; Lataifeh, I; Almousa, A; Jaradat, I

2011-01-01

In recent years, the role of positron emission tomography (PET) in the staging and management of gynecological cancers has been increasing. The aim of this study was to systematically review the role of PET in radiotherapy planning and brachytherapy treatment optimization in patients with cervical cancer. Systematic literature review. Systematic review of relevant literature addressing the utilization of PET and/or PET-computed tomography (CT) in external-beam radiotherapy planning and brachytherapy treatment optimization. We performed an extensive PubMed database search on 20 April 2011. Nineteen studies, including 759 patients, formed the basis of this systematic review. PET/ PET-CT is the most sensitive imaging modality for detecting nodal metastases in patients with cervical cancer and has been shown to impact external-beam radiotherapy planning by modifying the treatment field and customizing the radiation dose. This particularly applies to detection of previously uncovered para-aortic and inguinal nodal metastases. Furthermore, PET/ PET-CT guided intensity-modulated radiation therapy (IMRT) allows delivery of higher doses of radiation to the primary tumor, if brachytherapy is unsuitable, and to grossly involved nodal disease while minimizing treatment-related toxicity. PET/ PET-CT based brachytherapy optimization allows improved tumor-volume dose distribution and detailed 3D dosimetric evaluation of risk organs. Sequential PET/ PET-CT imaging performed during the course of brachytherapy form the basis of “adaptive” brachytherapy in cervical cancer. This review demonstrates the effectiveness of pretreatment PET/ PET-CT in cervical cancer patients treated by radiotherapy. Further prospective studies are required to define the group of patients who would benefit the most from this procedure.

Novel high dose rate lip brachytherapy technique to improve dose homogeneity and reduce toxicity by customized mold.

PubMed

Feldman, Jon; Appelbaum, Limor; Sela, Mordechay; Voskoboinik, Ninel; Kadouri, Sarit; Weinberger, Jeffrey; Orion, Itzhak; Meirovitz, Amichay

2014-12-23

The purpose of this study is to describe a novel brachytherapy technique for lip Squamous Cell Carcinoma, utilizing a customized mold with embedded brachytherapy sleeves, which separates the lip from the mandible, and improves dose homogeneity. Seven patients with T2 lip cancer treated with a "sandwich" technique of High Dose Rate (HDR) brachytherapy to the lip, consisting of interstitial catheters and a customized mold with embedded catheters, were reviewed for dosimetry and outcome using 3D planning. Dosimetric comparison was made between the "sandwich" technique to "classic" - interstitial catheters only plan. We compared dose volume histograms for Clinical Tumor Volume (CTV), normal tissue "hot spots" and mandible dose. We are reporting according to the ICRU 58 and calculated the Conformal Index (COIN) to show the advantage of our technique. The seven patients (ages 36-81 years, male) had median follow-up of 47 months. Four patients received Brachytherapy and External Beam Radiation Therapy, 3 patients received brachytherapy alone. All achieved local control, with excellent esthetic and functional results. All patients are disease free. The Customized Mold Sandwich technique (CMS) reduced the high dose region receiving 150% (V150) by an average of 20% (range 1-47%), The low dose region (les then 90% of the prescribed dose) improved by 73% in average by using the CMS technique. The COIN value for the CMS was in average 0.92 as opposed to 0.88 for the interstitial catheter only. All differences (excluding the low dose region) were statistically significant. The CMS technique significantly reduces the high dose volume and increases treatment homogeneity. This may reduce the potential toxicity to the lip and adjacent mandible, and results in excellent tumor control, cosmetic and functionality.

Dosimetric impact of an air passage on intraluminal brachytherapy for bronchus cancer

PubMed Central

Okamoto, Hiroyuki; Wakita, Akihisa; Nakamura, Satoshi; Nishioka, Shie; Aikawa, Ako; Kato, Toru; Abe, Yoshihisa; Kobayashi, Kazuma; Inaba, Koji; Murakami, Naoya; Itami, Jun

2016-01-01

The brachytherapy dose calculations used in treatment planning systems (TPSs) have conventionally been performed assuming homogeneous water. Using measurements and a Monte Carlo simulation, we evaluated the dosimetric impact of an air passage on brachytherapy for bronchus cancer. To obtain the geometrical characteristics of an air passage, we analyzed the anatomical information from CT images of patients who underwent intraluminal brachytherapy using a high-dose-rate 192Ir source (MicroSelectron V2r®, Nucletron). Using an ionization chamber, we developed a measurement system capable of measuring the peripheral dose with or without an air cavity surrounding the catheter. Air cavities of five different radii (0.3, 0.5, 0.75, 1.25 and 1.5 cm) were modeled by cylindrical tubes surrounding the catheter. A Monte Carlo code (GEANT4) was also used to evaluate the dosimetric impact of the air cavity. Compared with dose calculations in homogeneous water, the measurements and GEANT4 indicated a maximum overdose of 5–8% near the surface of the air cavity (with the maximum radius of 1.5 cm). Conversely, they indicated a minimum overdose of ~1% in the region 3–5 cm from the cavity surface for the smallest radius of 0.3 cm. The dosimetric impact depended on the size and the distance of the air passage, as well as the length of the treatment region. Based on dose calculations in water, the TPS for intraluminal brachytherapy for bronchus cancer had an unexpected overdose of 3–5% for a mean radius of 0.75 cm. This study indicates the need for improvement in dose calculation accuracy with respect to intraluminal brachytherapy for bronchus cancer. PMID:27605630

Custom-made micro applicators for high-dose-rate brachytherapy treatment of chronic psoriasis.

PubMed

Buzurovic, Ivan M; O'Farrell, Desmond A; Bhagwat, Mandar S; Hansen, Jorgen L; Harris, Thomas C; Friesen, Scott; Cormack, Robert A; Devlin, Phillip M

2017-06-01

In this study, we present the treatment of the psoriatic nail beds of patients refractory to standard therapies using high-dose-rate (HDR) brachytherapy. The custom-made micro applicators (CMMA) were designed and constructed for radiation dose delivery to small curvy targets with complicated topology. The role of the HDR brachytherapy treatment was to stimulate the T cells for an increased immune response. The patient diagnosed with psoriatic nail beds refractory to standard therapies received monthly subunguinal injections that caused significant pain and discomfort in both hands. The clinical target was defined as the length from the fingertip to the distal interphalangeal joint. For the accurate and reproducible setup in the multi-fractional treatment delivery, the CMMAs were designed. Five needles were embedded into the dense plastic mesh and covered with 5 mm bolus material for each micro applicator. Five CMMAs were designed, resulting in the usage of 25 catheters in total. The prescription dose was planned to the depth of the anterior surface of the distal phalanx, allowing for the sparing of the surrounding tissue. The total number of the active dwell positions was 145 with step size of 5 mm. The total treatment time was 115 seconds with a 7.36 Ci activity of the 192 Ir source. The treatment resulted in good pain control. The patient did not require further injections to the nail bed. After this initial treatment, additional two patients with similar symptoms received HDR brachytherapy. The treatment outcome was favorable in all cases. The first HDR brachytherapy treatment of psoriasis of the nail bed is presented. The initial experience revealed that brachytherapy treatment was well-tolerated and resulted in adequate control of the disease. A larger cohort of patients will be required for additional conclusions related to the long-term clinical benefits.

Dose distribution verification for GYN brachytherapy using EBT Gafchromic film and TG-43 calculation.

PubMed

Gholami, Somayeh; Mirzaei, Hamid Reza; Jabbary Arfaee, Ali; Jaberi, Ramin; Nedaie, Hassan Ali; Rabi Mahdavi, Seied; Rajab Bolookat, Eftekhar; Meigooni, Ali S

2016-01-01

Verification of dose distributions for gynecological (GYN) brachytherapy implants using EBT Gafchromic film. One major challenge in brachytherapy is to verify the accuracy of dose distributions calculated by a treatment planning system. A new phantom was designed and fabricated using 90 slabs of 18 cm × 16 cm × 0.2 cm Perspex to accommodate a tandem and Ovoid assembly, which is normally used for GYN brachytherapy treatment. This phantom design allows the use of EBT Gafchromic films for dosimetric verification of GYN implants with a cobalt-60 HDR system or a LDR Cs-137 system. Gafchromic films were exposed using a plan that was designed to deliver 1.5 Gy of dose to 0.5 cm distance from the lateral surface of ovoids from a pair of ovoid assembly that was used for treatment vaginal cuff. For a quantitative analysis of the results for both LDR and HDR systems, the measured dose values at several points of interests were compared with the calculated data from a commercially available treatment planning system. This planning system was utilizing the TG-43 formalism and parameters for calculation of dose distributions around a brachytherapy implant. The results of these investigations indicated that the differences between the calculated and measured data at different points were ranging from 2.4% to 3.8% for the LDR Cs-137 and HDR Co-60 systems, respectively. The EBT Gafchromic films combined with the newly designed phantom could be utilized for verification of the dose distributions around different GYN implants treated with either LDR or HDR brachytherapy procedures.

Ejaculatory Function After Permanent {sup 125}I Prostate Brachytherapy for Localized Prostate Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huyghe, Eric; Department of Urology and Andrology, Paul Sabatier University, CHU Paule de Viguier, Toulouse; Delannes, Martine

Purpose: Ejaculatory function is an underreported aspect of male sexuality in men treated for prostate cancer. We conducted the first detailed analysis of ejaculatory function in patients treated with permanent {sup 125}I prostate brachytherapy for localized prostate cancer. Patients and Methods: Of 270 sexually active men with localized prostate cancer treated with permanent {sup 125}I prostate brachytherapy, 241 (89%), with a mean age of 65 years (range, 43-80), responded to a mailed questionnaire derived from the Male Sexual Health Questionnaire regarding ejaculatory function. Five aspects of ejaculatory function were examined: frequency, volume, dry ejaculation, pleasure, and pain. Results: Of themore » 241 sexually active men, 81.3% had conserved ejaculatory function after prostate brachytherapy; however, the number of patients with rare/absent ejaculatory function was double the pretreatment number (p < .0001). The latter finding was correlated with age (p < .001) and the preimplant International Index of Erectile Function score (p < .001). However, 84.9% of patients with maintained ejaculatory function after implantation reported a reduced volume of ejaculate compared with 26.9% before (p < .001), with dry ejaculation accounting for 18.7% of these cases. After treatment, 30.3% of the patients experienced painful ejaculation compared with 12.9% before (p = .0001), and this was associated with a greater number of implanted needles (p = .021) and the existence of painful ejaculation before implantation (p < .0001). After implantation, 10% of patients who continued to be sexually active experienced no orgasm compared with only 1% before treatment. in addition, more patients experienced late/difficult or weak orgasms (p = .001). Conclusion: Most men treated with brachytherapy have conserved ejaculatory function after prostate brachytherapy. However, most of these men experience a reduction in volume and a deterioration in orgasm.« less

[Orgasm after curietherapy with permanent iodine-125 radioimplants for localized prostate cancer].

PubMed

Delaunay, B; Delannes, M; Salloum, A; Delavierre, D; Wagner, F; Jonca, F; Thoulouzan, M; Plante, P; Bachaud, J-M; Soulie, M; Huyghe, E

2011-12-01

Orgasm is a domain of male sexuality that remains underreported in literature. Our aim was to realize the first detailed analysis of orgasm in patients treated by 125 I permanent prostate brachytherapy for localized prostate cancer. In a series of 270 sexually active men treated by prostate brachytherapy (125I permanent implantation), 241 (89%), mean age of 65 (43-80), participated in a mailed survey about sexual function after a mean time of 36 months (9-70). Erectile and ejaculatory functions and orgasm were explored using a mailed questionnaire. Two questions focused on orgasm. The first was about quality of orgasm (fast/intense/late, difficult/weak/absent) and the second about the presence of painful orgasm and its frequency (always/sometimes/often). After prostate brachytherapy, 81.3% of sexually active men conserved ejaculation and 90% orgasm. There was a significant deterioration of the quality of orgasm (P=0.0001). More than 50% of the patients had an altered orgasm (weak, difficult, absent) after brachytherapy, vs 16% before implantation (P=0.001). Men with a diminished ejaculation volume often had a weak/difficult orgasm (P=0.007). Neoadjuvant hormonal therapy did not seem to impact the quality of orgasm or the frequency of painful ejaculation. Patients who had an IIEF-5 score higher than 12 had frequently intense orgasm (26.7% vs 2.7%; P<0.001) after brachytherapy. Sixty patients (30.3%) experienced often/sometimes painful ejaculation 12.9% (n=31) before implantation (P=0.0001). Most of the patients treated by prostate brachytherapy conserved orgasm after treatment. However, most of the patients described a deterioration of the quality of orgasm. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Ejaculatory function after permanent 125I prostate brachytherapy for localized prostate cancer.

PubMed

Huyghe, Eric; Delannes, Martine; Wagner, Fabien; Delaunay, Boris; Nohra, Joe; Thoulouzan, Matthieu; Shut-Yee, J Yeung; Plante, Pierre; Soulie, Michel; Thonneau, Patrick; Bachaud, Jean Marc

2009-05-01

Ejaculatory function is an underreported aspect of male sexuality in men treated for prostate cancer. We conducted the first detailed analysis of ejaculatory function in patients treated with permanent (125)I prostate brachytherapy for localized prostate cancer. Of 270 sexually active men with localized prostate cancer treated with permanent (125)I prostate brachytherapy, 241 (89%), with a mean age of 65 years (range, 43-80), responded to a mailed questionnaire derived from the Male Sexual Health Questionnaire regarding ejaculatory function. Five aspects of ejaculatory function were examined: frequency, volume, dry ejaculation, pleasure, and pain. Of the 241 sexually active men, 81.3% had conserved ejaculatory function after prostate brachytherapy; however, the number of patients with rare/absent ejaculatory function was double the pretreatment number (p < .0001). The latter finding was correlated with age (p < .001) and the preimplant International Index of Erectile Function score (p < .001). However, 84.9% of patients with maintained ejaculatory function after implantation reported a reduced volume of ejaculate compared with 26.9% before (p < .001), with dry ejaculation accounting for 18.7% of these cases. After treatment, 30.3% of the patients experienced painful ejaculation compared with 12.9% before (p = .0001), and this was associated with a greater number of implanted needles (p = .021) and the existence of painful ejaculation before implantation (p < .0001). After implantation, 10% of patients who continued to be sexually active experienced no orgasm compared with only 1% before treatment. in addition, more patients experienced late/difficult or weak orgasms (p = .001). Most men treated with brachytherapy have conserved ejaculatory function after prostate brachytherapy. However, most of these men experience a reduction in volume and a deterioration in orgasm.

Superficial ocular malignancies treated with strontium-90 brachytherapy: long term outcomes.

PubMed

Laskar, Siddhartha; Gurram, Lavanya; Laskar, Sarbani Ghosh; Chaudhari, Suresh; Khanna, Nehal; Upreti, Rituraj

2015-10-01

The incidence of conjunctival malignancies is less than 1%. Though surgical excision remains the mainstay of treatment, the incidence of positive surgical margins and local recurrence rates are high, which is approximately up to 33% in negative margins and 56% in positive margins. Radiotherapy reduces the risk of recurrence in these cases. Brachytherapy using β emitters such as strontium-90 ((90)Sr) is an ideal treatment technique for these tumors with the advantage of treating only a few millimeters of tissue while sparing the underlying normal eye. We report the long term outcomes in the form of local control and late sequelae of patients with conjunctival malignancies treated with (90)Sr applicator brachytherapy. During 1999-2013, 13 patients with conjunctival tumors, treated using (90)Sr brachytherapy were analyzed. Brachytherapy was either in a post-operative adjuvant or in a recurrent setting. Local control (LC), disease free survival (DFS), overall survival (OS), and late sequelae were evaluated. The median age at presentation was 47 years (range: 11-71 years). Thirteen patients with 15 tumors were treated. The commonest histology was squamous cell carcinoma. The median dose was 44 Gy over 11 fractions. The median follow up of all the patients was 51 months (range: 3-139 months). The median follow up of patients with carcinoma only was 64 months with a LC and DFS of 90.9% at 5 years. None of the patients developed ≥ grade II Radiation Therapy Oncology Group (RTOG) acute toxicities. One patient developed a focal scar and another developed corneal opacification at the limbus. Vision was not impaired in any of the patients. Strontium-90 brachytherapy used in early invasive conjunctival malignancies as an adjunct to surgery in primary and recurrent settings, results in optimal disease control and ocular functional outcomes.

TU-AB-201-03: A Robot for the Automated Delivery of An Electromagnetic Tracking Sensor for the Localization of Brachytherapy Catheters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Don, S; Cormack, R; Viswanathan, A

Purpose: To present a programmable robotic system for the accurate and fast deployment of an electromagnetic (EM) sensor for brachytherapy catheter localization. Methods: A robotic system for deployment of an EM sensor was designed and built. The system was programmed to increment the sensor position at specified time and space intervals. Sensor delivery accuracy was measured in a phantom using the localization of the EM sensor and tested in different environmental conditions. Accuracy was tested by measuring the distance between the physical locations reached by the sensor (measured by the EM tracker) and the intended programmed locations. Results: The systemmore » consisted of a stepper motor connected to drive wheels (that grip the cable to move the sensor) and a series of guides to connect to a brachytherapy transfer tube, all controlled by a programmable Arduino microprocessor. The total cost for parts was <$300. The positional accuracy of the sensor location was within 1 mm of the expected position provided by the motorized guide system. Acquisition speed to localize a brachytherapy catheter with 20 cm of active length was 10 seconds. The current design showed some cable slip and warping depending on environment temperature. Conclusion: The use of EM tracking for the localization of brachytherapy catheters has been previously demonstrated. Efficient data acquisition and artifact reduction requires fast and accurate deployment of an EM sensor in consistent, repeatable patterns, which cannot practically be achieved manually. The design of an inexpensive, programmable robot allowing for the precise deployment of stepping patterns was presented, and a prototype was built. Further engineering is necessary to ensure that the device provides efficient independent localization of brachytherapy catheters. This research was funded by the Kaye Family Award.« less

High-dose-rate interstitial brachytherapy for the treatment of high-volume locally recurrent endometrial carcinoma.

PubMed

Huang, Kitty; D'Souza, David; Patil, Nikhilesh; Velker, Vikram; Leung, Eric; Stitt, Larry; Whiston, Frances; Sugimoto, Akira; McGee, Jacob; Prefontaine, Michel

2016-01-01

Limited therapeutic options are available for the treatment of locally recurrent endometrial carcinoma. Our objective was to report an institutional experience using interstitial brachytherapy (IBT) to treat significant recurrent endometrial carcinoma, including previously irradiated disease. Between December 2004 and September 2012, 40 patients with high-volume locally recurrent endometrial cancer were treated by high-dose-rate IBT (± external beam radiation therapy EBRT). Sixteen patients had prior radiotherapy: EBRT alone (n = 5), intracavitary brachytherapy alone (n = 3), or EBRT with intracavitary brachytherapy boost (n = 8). Actuarial outcome rates were calculated using the Kaplan-Meier method and compared using the log-rank test. Median followup interval was 18 months. Median disease-free interval was 61 months. Actuarial local control, progression-free survival (PFS), and overall survival were 74% and 60%, 70% and 51%, and 83% and 72% at 12 and 24 months, respectively. p-Values for local control, progression-free survival, and overall survival between patient who had prior RT (n = 16) to no prior RT (n = 24) were p = 0.38, 0.32, and 0.90, respectively. Acute toxicities include Grade 1-2 pain (5%), genitourinary (7%), gastrointestinal (12%), soft tissue (5%), and dermatologic (12%). Four patients observed late Grade 3-4 toxicities, including rectal bleeding/fistula and soft tissue necrosis. High-dose-rate IBT is an effective treatment for locally recurrent endometrial carcinoma with an acceptable toxicity profile. Outcomes are similar between previously irradiated and nonirradiated patients. In women who have received prior radiotherapy and are often considered for palliative treatment, interstitial brachytherapy is a potentially curative option. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

High-dose-rate (HDR) brachytherapy for the treatment of benign obstructive endobronchial granulation tissue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Madu, Chika N.; Machuzak, Michael S.; Sterman, Daniel H.

Background: Severe airway obstruction can occur in the setting of benign granulation tissue forming at bronchial anastomotic sites after lung transplantation in up to 20% of patients. Many of these benign lesions respond to stent placement, laser ablation, or balloon bronchoplasty. However, in certain cases, proliferation of granulation tissue may persist despite all therapeutic attempts. This study describes a series of refractory patients treated with high-dose-rate (HDR) brachytherapy for benign proliferation of granulation tissue, causing airway compromise. Methods and Materials: Between April 2002 and June 2005, 5 patients with significant airway compromise from recurrent granulation tissue were treated with HDRmore » brachytherapy. All patients had previously failed to maintain a patent airway despite multiple bronchoscopic interventions. Treatment was delivered using an HDR brachytherapy afterloader with {sup 192}Ir. Dose prescription was to a depth of 1 cm. All patients were treated weekly, with total doses ranging from 10 Gy to 21 Gy in two to three fractions. Results: The median follow-up was 12 months. All patients experienced a reduction in therapeutic bronchoscopic procedures after HDR brachytherapy compared with the pretreatment period. With the exception of possible radiation-induced bronchitis in 1 patient, there were no other treatment related complications. At the time of this report, 2 patients have died and the other 3 are alive with marked symptomatic improvement and reduced bronchoscopic procedures. Conclusion: High-dose-rate brachytherapy is an effective treatment for benign proliferation of granulation tissue causing airway obstruction. The early response to therapy is encouraging and further follow-up is necessary to determine long-term durability and late effects.« less

WE-F-201-00: Practical Guidelines for Commissioning Advanced Brachytherapy Dose Calculation Algorithms

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2015-06-15

With the recent introduction of heterogeneity correction algorithms for brachytherapy, the AAPM community is still unclear on how to commission and implement these into clinical practice. The recently-published AAPM TG-186 report discusses important issues for clinical implementation of these algorithms. A charge of the AAPM-ESTRO-ABG Working Group on MBDCA in Brachytherapy (WGMBDCA) is the development of a set of well-defined test case plans, available as references in the software commissioning process to be performed by clinical end-users. In this practical medical physics course, specific examples on how to perform the commissioning process are presented, as well as descriptions of themore » clinical impact from recent literature reporting comparisons of TG-43 and heterogeneity-based dosimetry. Learning Objectives: Identify key clinical applications needing advanced dose calculation in brachytherapy. Review TG-186 and WGMBDCA guidelines, commission process, and dosimetry benchmarks. Evaluate clinical cases using commercially available systems and compare to TG-43 dosimetry.« less

Deformable anatomical templates for brachytherapy treatment planning in radiotherapy of cervical cancer

NASA Astrophysics Data System (ADS)

Christensen, Gary E.; Williamson, Jeffrey F.; Chao, K. S. C.; Miller, Michael I.; So, F. B.; Vannier, Michael W.

1997-10-01

This paper describes a new method to register serial, volumetric x-ray computed tomography (CT) data sets for tracking soft-tissue deformation caused by insertion of intracavity brachytherapy applicators to treat cervical cancer. 3D CT scans collected from the same patient with and without a brachytherapy applicator are registered to aid in computation of the radiation dose to tumor and normal tissue. The 3D CT image volume of pelvic anatomy with the applicator. Initial registration is accomplished by rigid alignment of the pelvic bones and non-rigid alignment of gray scale CT data and hand segmentations of the vagina, cervix, bladder, and rectum. A viscous fluid transformation model is used for non-rigid registration to allow for local, non-linear registration of the vagina, cervix, bladder, and rectum without disturbing the rigid registration of the bony pelvis and adjacent structures. Results are presented in which two 3D CT data sets of the same patient - imaged with and without a brachytherapy applicator - are registered.

Does brachytherapy of the prostate affect sperm quality and/or fertility in younger men?

PubMed

Mydlo, Jack H; Lebed, Brett

2004-01-01

Sperm banking prior to surgical procedures which may affect fertility, such as retroperitoneal lymph node dissection, has been well documented. However, such procedures are usually performed in young men. With older men marrying later in life, or remarrying, we wanted to investigate the effects of radiation on prostate cancer patients who wanted to have children afterwards. We encountered several patients with prostate cancer who decided to undergo brachytherapy and were planning to have more children. We performed a search using PubMed and Ovid for the period 1966-2001 using the key words "fertility", "sperm banking", "radiation effects", "prostate cancer" and "brachytherapy". Of the four young patients we encountered who underwent brachytherapy, we found no significant change in semen parameters post-therapy, and three of them were able to father a child subsequently without any deleterious side-effects. It has been demonstrated in several reports that external-beam radiation therapy is associated with decreased spermatogenesis due to Leydig cell dysfunction and decreased serum testosterone, as well as having a direct effect on spermatogonia. However, there is a scarcity of literature discussing the effects of prostate brachytherapy on spermatogenesis as the patients involved are usually older and usually do not desire to father any more children. As I has a half-life of 60 days, we used an exposure of 10 mR/h at the symphysis pubis and used integration to find the total dose exposed to the testis as follows: Limits 14 400 to 0, S 10e (-In2/1440.Tdt) where T = 14 400 and 20.75 R = 20.75 cGy. Therefore, the total dose was 20.75 cGy x 0.91 = 18.88 cGy. This value is considered too low to have any significant effect on testicular tissues. We speculate that the effects of prostate brachytherapy on spermatogenesis in prostate cancer patients are minimal. However, due to the half-life of I, we recommend that these patients should wait for at least 3-4 months before trying to conceive. Furthermore, younger men with prostate cancer may want to consider sperm banking prior to brachytherapy if they want to have children in the future.

Evaluation of Delivery Costs for External Beam Radiation Therapy and Brachytherapy for Locally Advanced Cervical Cancer Using Time-Driven Activity-Based Costing.

PubMed

Bauer-Nilsen, Kristine; Hill, Colin; Trifiletti, Daniel M; Libby, Bruce; Lash, Donna H; Lain, Melody; Christodoulou, Deborah; Hodge, Constance; Showalter, Timothy N

2018-01-01

To evaluate the delivery costs, using time-driven activity-based costing, and reimbursement for definitive radiation therapy for locally advanced cervical cancer. Process maps were created to represent each step of the radiation treatment process and included personnel, equipment, and consumable supplies used to deliver care. Personnel were interviewed to estimate time involved to deliver care. Salary data, equipment purchasing information, and facilities costs were also obtained. We defined the capacity cost rate (CCR) for each resource and then calculated the total cost of patient care according to CCR and time for each resource. Costs were compared with 2016 Medicare reimbursement and relative value units (RVUs). The total cost of radiation therapy for cervical cancer was $12,861.68, with personnel costs constituting 49.8%. Brachytherapy cost $8610.68 (66.9% of total) and consumed 423 minutes of attending radiation oncologist time (80.0% of total). External beam radiation therapy cost $4055.01 (31.5% of total). Personnel costs were higher for brachytherapy than for the sum of simulation and external beam radiation therapy delivery ($4798.73 vs $1404.72). A full radiation therapy course provides radiation oncologists 149.77 RVUs with intensity modulated radiation therapy or 135.90 RVUs with 3-dimensional conformal radiation therapy, with total reimbursement of $23,321.71 and $16,071.90, respectively. Attending time per RVU is approximately 4-fold higher for brachytherapy (5.68 minutes) than 3-dimensional conformal radiation therapy (1.63 minutes) or intensity modulated radiation therapy (1.32 minutes). Time-driven activity-based costing was used to calculate the total cost of definitive radiation therapy for cervical cancer, revealing that brachytherapy delivery and personnel resources constituted the majority of costs. However, current reimbursement policy does not reflect the increased attending physician effort and delivery costs of brachytherapy. We hypothesize that the significant discrepancy between treatment costs and physician effort versus reimbursement may be a potential driver of reported national trends toward poor compliance with brachytherapy, and we suggest re-evaluation of payment policies to incentivize quality care. Copyright © 2017 Elsevier Inc. All rights reserved.

Impact of dosimetric and clinical parameters on clinical side effects in cervix cancer patients treated with 3D pulse-dose-rate intracavitary brachytherapy.

PubMed

Levitchi, Mihai; Charra-Brunaud, Claire; Quetin, Philippe; Haie-Meder, Christine; Kerr, Christine; Castelain, Bernard; Delannes, Martine; Thomas, Laurence; Desandes, Emmanuel; Peiffert, Didier

2012-06-01

To assess the association between dosimetric/clinical parameters and gastrointestinal/urinary grade 2-4 side effects in cervix cancer patients treated with 3D pulse dose rate brachytherapy. Three hundred and fifty-two patients received brachytherapy associated with external-beam radiotherapy (EBRT) for 266 of them; 236 patients underwent surgery. The doses for the most exposed 2, and 0.1 cm(3) (D(2cc) and D(0.1cc)) volumes of the rectum and bladder as well as bladder ICRU point dose (D(ICRU)) were converted into isoeffective doses in 2-Gy fractions. The clinical parameters analyzed were: age, smoking habits, arteritis, diabetes, previous pelvic surgery, FIGO stage, nodal status, pathology, pelvic surgery, EBRT and chemotherapy. Side effects were prospectively assessed using the CTCAEv3.0. Cutoff dose levels were defined separately for patients treated with EBRT and brachytherapy (Group 1) and with preoperative brachytherapy (Group 2). The median follow-up was 23.4months. In Group 1 a significant predictive value of rectum D(0.1cc) and D(2cc), bladder D(0.1cc) and D(ICRU) for gastrointestinal and urinary toxicity was found using as cutoff 83, 68, 109 and 68Gy(α)(/)(β)(3). In Group 2 a significant predictive value of bladder D(0.1cc), D(2cc) and D(ICRU) for urinary toxicity was found using as cutoff 141, 91 and 67Gy(α)(/)(β)(3), but not for the rectum D(0.1cc) and D(2cc); smoking had a significant predictive value on urinary toxicity. For patients treated with brachytherapy and EBRT, rectum D(0.1cc) and D(2cc) and bladder D(0.1cc) and D(ICRU) had a predictive value for toxicity. For patients treated with preoperative brachytherapy, bladder D(0.1cc), D(2cc) and D(ICRU) and smoking had a predictive value for urinary toxicity. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Dynamic modulated brachytherapy (DMBT) and intensity modulated brachytherapy (IMBT) for the treatment of rectal and breast carcinomas

NASA Astrophysics Data System (ADS)

Webster, Matthew Julian

The ultimate goal of any treatment of cancer is to maximize the likelihood of killing the tumor while minimizing the chance of damaging healthy tissues. One of the most effective ways to accomplish this is through radiation therapy, which must be able to target the tumor volume with a high accuracy while minimizing the dose delivered to healthy tissues. A successful method of accomplishing this is brachytherapy which works by placing the radiation source in very close proximity to the tumor. However, most current applications of brachytherapy rely mostly on the geometric manipulation of isotropic sources, which limits the ability to specifically target the tumor. The purpose of this work is to introduce several types of shielded brachytherapy applicators which are capable of targeting tumors with much greater accuracy than existing technologies. These applicators rely on the modulation of the dose profile through a high-density tungsten alloy shields to create anisotropic dose distributions. Two classes of applicators have been developed in this work. The first relies on the active motion of the shield, to aim a highly directional radiation profile. This allows for very precise control of the dose distribution for treatment, achieving unparalleled dose coverage to the tumor while sparing healthy tissues. This technique has been given the moniker of Dynamic Modulated Brachytherapy (DMBT). The second class of applicators, designed to reduce treatment complexity uses static applicators. These applicators retain the use of the tungsten shield, but the shield is motionless during treatment. By intelligently designing the shield, significant improvements over current methods have been demonstrated. Although these static applicators fail to match the dosimetric quality of DMBT applicators the simplified setup and treatment procedure gives them significant appeal. The focus of this work has been to optimize these shield designs, specifically for the treatment of rectal and breast carcinomas. The use of Monte Carlo methods and development of optimization algorithms have played a prominent role in accomplishing this. The use of shielded applicators, such as the ones described here, is the next logical step in the rapidly evolving field of brachytherapy.

[Usefulness of urethral endoprosthesis in the management of urinary retention after brachytherapy for localized prostate cancer].

PubMed

Kerkeni, W; Chahwan, C; Lenormand, C; Dubray, B; Benyoucef, A; Pfister, C

2014-03-01

Brachytherapy is a possible treatment for localized low risk prostate cancer. Although this option is minimally invasive, some side effects may occur. Acute retention of urine (ARU) has been observed in 5% to 22% of cases and can be prevented in most cases by alpha-blocker treatment. Several alternatives have been reported in the literature for the management of ARU following brachytherapy: prolonged suprapubic catheterization, transurethral resection of the prostate and also intermittent self-catheterization. The authors report an original endoscopic approach, using urethral endoprosthesis, with a satisfactory voiding status. Copyright © 2013. Published by Elsevier Masson SAS.

Adjuvant vaginal brachytherapy as a part of management in early endometrial cancer

PubMed Central

Wojcieszek, Piotr; Białas, Brygida

2012-01-01

Endometrial cancer is the most frequent cancer of female genital tract. Metro- and menorrhagia or postmenopausal bleeding results in its early presentation. It allows radical treatment. However, controversies remain on surgery coverage or adjuvant therapies in early endometrial women cancer. Optimal management should minimize intervention instead of aggressive approach, as showed by recent studies. There is a role for brachytherapy as an adjuvant irradiation. Crucial publications including PORTEC-1, GOG 99, MRC ASTEC, ASTEC/EN.5, PORTEC-2 or Italian lymphadenectomy trial are discussed. Moreover, there is attention paid on adjuvant vaginal brachytherapy analyses for the past fifteen years. PMID:23378855

Improved radial dose function estimation using current version MCNP Monte-Carlo simulation: Model 6711 and ISC3500 125I brachytherapy sources.

PubMed

Duggan, Dennis M

2004-12-01

Improved cross-sections in a new version of the Monte-Carlo N-particle (MCNP) code may eliminate discrepancies between radial dose functions (as defined by American Association of Physicists in Medicine Task Group 43) derived from Monte-Carlo simulations of low-energy photon-emitting brachytherapy sources and those from measurements on the same sources with thermoluminescent dosimeters. This is demonstrated for two 125I brachytherapy seed models, the Implant Sciences Model ISC3500 (I-Plant) and the Amersham Health Model 6711, by simulating their radial dose functions with two versions of MCNP, 4c2 and 5.

Magnetic resonance spectroscopy-guided transperineal prostate biopsy and brachytherapy for recurrent prostate cancer.

PubMed

Barnes, Agnieszka Szot; Haker, Steven J; Mulkern, Robert V; So, Minna; D'Amico, Anthony V; Tempany, Clare M

2005-12-01

Brachytherapy targeted to the peripheral zone with magnetic resonance imaging (MRI) guidance is a prostate cancer treatment option with potentially fewer complications than other treatments. Follow-up MRI when failure is suspected is, however, difficult because of radiation-induced changes. Furthermore, MR spectroscopy (MRS) is compromised by susceptibility artifacts from radioactive seeds in the peripheral zone. We report a case in which combined MRI/MRS was useful for the detection of prostate cancer in the transitional zone in patients previously treated with MR-guided brachytherapy. We propose that MRI/MRS can help detect recurrent prostate cancer, guide prostate biopsy, and help manage salvage treatment decisions.

Dosimetric characterization and output verification for conical brachytherapy surface applicators. Part I. Electronic brachytherapy source

PubMed Central

Fulkerson, Regina K.; Micka, John A.; DeWerd, Larry A.

2014-01-01

Purpose: Historically, treatment of malignant surface lesions has been achieved with linear accelerator based electron beams or superficial x-ray beams. Recent developments in the field of brachytherapy now allow for the treatment of surface lesions with specialized conical applicators placed directly on the lesion. Applicators are available for use with high dose rate (HDR) 192Ir sources, as well as electronic brachytherapy sources. Part I of this paper will discuss the applicators used with electronic brachytherapy sources; Part II will discuss those used with HDR 192Ir sources. Although the use of these applicators has gained in popularity, the dosimetric characteristics including depth dose and surface dose distributions have not been independently verified. Additionally, there is no recognized method of output verification for quality assurance procedures with applicators like these. Existing dosimetry protocols available from the AAPM bookend the cross-over characteristics of a traditional brachytherapy source (as described by Task Group 43) being implemented as a low-energy superficial x-ray beam (as described by Task Group 61) as observed with the surface applicators of interest. Methods: This work aims to create a cohesive method of output verification that can be used to determine the dose at the treatment surface as part of a quality assurance/commissioning process for surface applicators used with HDR electronic brachytherapy sources (Part I) and 192Ir sources (Part II). Air-kerma rate measurements for the electronic brachytherapy sources were completed with an Attix Free-Air Chamber, as well as several models of small-volume ionization chambers to obtain an air-kerma rate at the treatment surface for each applicator. Correction factors were calculated using MCNP5 and EGSnrc Monte Carlo codes in order to determine an applicator-specific absorbed dose to water at the treatment surface from the measured air-kerma rate. Additionally, relative dose measurements of the surface dose distributions and characteristic depth dose curves were completed in-phantom. Results: Theoretical dose distributions and depth dose curves were generated for each applicator and agreed well with the measured values. A method of output verification was created that allows users to determine the applicator-specific dose to water at the treatment surface based on a measured air-kerma rate. Conclusions: The novel output verification methods described in this work will reduce uncertainties in dose delivery for treatments with these kinds of surface applicators, ultimately improving patient care. PMID:24506635

AAPM and GEC-ESTRO guidelines for image-guided robotic brachytherapy: report of Task Group 192.

PubMed

Podder, Tarun K; Beaulieu, Luc; Caldwell, Barrett; Cormack, Robert A; Crass, Jostin B; Dicker, Adam P; Fenster, Aaron; Fichtinger, Gabor; Meltsner, Michael A; Moerland, Marinus A; Nath, Ravinder; Rivard, Mark J; Salcudean, Tim; Song, Danny Y; Thomadsen, Bruce R; Yu, Yan

2014-10-01

In the last decade, there have been significant developments into integration of robots and automation tools with brachytherapy delivery systems. These systems aim to improve the current paradigm by executing higher precision and accuracy in seed placement, improving calculation of optimal seed locations, minimizing surgical trauma, and reducing radiation exposure to medical staff. Most of the applications of this technology have been in the implantation of seeds in patients with early-stage prostate cancer. Nevertheless, the techniques apply to any clinical site where interstitial brachytherapy is appropriate. In consideration of the rapid developments in this area, the American Association of Physicists in Medicine (AAPM) commissioned Task Group 192 to review the state-of-the-art in the field of robotic interstitial brachytherapy. This is a joint Task Group with the Groupe Européen de Curiethérapie-European Society for Radiotherapy & Oncology (GEC-ESTRO). All developed and reported robotic brachytherapy systems were reviewed. Commissioning and quality assurance procedures for the safe and consistent use of these systems are also provided. Manual seed placement techniques with a rigid template have an estimated in vivo accuracy of 3-6 mm. In addition to the placement accuracy, factors such as tissue deformation, needle deviation, and edema may result in a delivered dose distribution that differs from the preimplant or intraoperative plan. However, real-time needle tracking and seed identification for dynamic updating of dosimetry may improve the quality of seed implantation. The AAPM and GEC-ESTRO recommend that robotic systems should demonstrate a spatial accuracy of seed placement ≤1.0 mm in a phantom. This recommendation is based on the current performance of existing robotic brachytherapy systems and propagation of uncertainties. During clinical commissioning, tests should be conducted to ensure that this level of accuracy is achieved. These tests should mimic the real operating procedure as closely as possible. Additional recommendations on robotic brachytherapy systems include display of the operational state; capability of manual override; documented policies for independent check and data verification; intuitive interface displaying the implantation plan and visualization of needle positions and seed locations relative to the target anatomy; needle insertion in a sequential order; robot-clinician and robot-patient interactions robustness, reliability, and safety while delivering the correct dose at the correct site for the correct patient; avoidance of excessive force on radioactive sources; delivery confirmation of the required number or position of seeds; incorporation of a collision avoidance system; system cleaning, decontamination, and sterilization procedures. These recommendations are applicable to end users and manufacturers of robotic brachytherapy systems.

Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources.

PubMed

Ghorbani, Mahdi; Mehrpouyan, Mohammad; Davenport, David; Ahmadi Moghaddas, Toktam

2016-06-01

The aim of this study is to quantify the influence of the photon energy spectrum of brachytherapy sources on task group No. 43 (TG-43) dosimetric parameters. Different photon spectra are used for a specific radionuclide in Monte Carlo simulations of brachytherapy sources. MCNPX code was used to simulate 125I, 103Pd, 169Yb, and 192Ir brachytherapy sources. Air kerma strength per activity, dose rate constant, radial dose function, and two dimensional (2D) anisotropy functions were calculated and isodose curves were plotted for three different photon energy spectra. The references for photon energy spectra were: published papers, Lawrence Berkeley National Laboratory (LBNL), and National Nuclear Data Center (NNDC). The data calculated by these photon energy spectra were compared. Dose rate constant values showed a maximum difference of 24.07% for 103Pd source with different photon energy spectra. Radial dose function values based on different spectra were relatively the same. 2D anisotropy function values showed minor differences in most of distances and angles. There was not any detectable difference between the isodose contours. Dosimetric parameters obtained with different photon spectra were relatively the same, however it is suggested that more accurate and updated photon energy spectra be used in Monte Carlo simulations. This would allow for calculation of reliable dosimetric data for source modeling and calculation in brachytherapy treatment planning systems.

Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources

PubMed Central

Ghorbani, Mahdi; Davenport, David

2016-01-01

Abstract Aim The aim of this study is to quantify the influence of the photon energy spectrum of brachytherapy sources on task group No. 43 (TG-43) dosimetric parameters. Background Different photon spectra are used for a specific radionuclide in Monte Carlo simulations of brachytherapy sources. Materials and methods MCNPX code was used to simulate 125I, 103Pd, 169Yb, and 192Ir brachytherapy sources. Air kerma strength per activity, dose rate constant, radial dose function, and two dimensional (2D) anisotropy functions were calculated and isodose curves were plotted for three different photon energy spectra. The references for photon energy spectra were: published papers, Lawrence Berkeley National Laboratory (LBNL), and National Nuclear Data Center (NNDC). The data calculated by these photon energy spectra were compared. Results Dose rate constant values showed a maximum difference of 24.07% for 103Pd source with different photon energy spectra. Radial dose function values based on different spectra were relatively the same. 2D anisotropy function values showed minor differences in most of distances and angles. There was not any detectable difference between the isodose contours. Conclusions Dosimetric parameters obtained with different photon spectra were relatively the same, however it is suggested that more accurate and updated photon energy spectra be used in Monte Carlo simulations. This would allow for calculation of reliable dosimetric data for source modeling and calculation in brachytherapy treatment planning systems. PMID:27247558

Exclusive low-dose-rate brachytherapy in 279 patients with T2N0 mobile tongue carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bourgier, Celine; Coche-Dequeant, Bernard; Fournier, Charles

2005-10-01

Purpose: To evaluate the therapeutic results obtained with {sup 192}Ir low-dose-rate interstitial brachytherapy in T2N0 mobile tongue carcinoma. Patients and Methods: Between December 1979 and January 1998, 279 patients with T2N0 mobile tongue carcinoma were treated by exclusive low-dose-rate brachytherapy, with or without neck dissection. {sup 192}Ir brachytherapy was performed according to the 'Paris system' with a median total dose of 60 Gy (median dose rate, 0.5 Gy/h). Results: Overall survival was 74.3% and 46.6% at 2 and 5 years. Local control was 79.1% at 2 years and regional control, respectively, 75.9% and 69.5% at 2 and 5 years (Kaplan-Meiermore » method). Systematic dissection revealed 44.6% occult node metastases, and histologic lymph node involvement was identified as the main significant factor for survival. Complication rate was 16.5% (Grade 3, 2.9%). Half of the patients presented previous and/or successive malignant tumor (ear-nose-throat, esophagus, or bronchus). Conclusion: Exclusive low-dose-rate brachytherapy is an effective treatment for T2 tongue carcinoma. Regional control and survival are excellent in patients undergoing systematic neck dissection, which is mandatory in our experience because of a high rate of occult lymph node metastases.« less

Implementation of image-guided brachytherapy (IGBT) for patients with uterine cervix cancer: a tumor volume kinetics approach

PubMed Central

Mendez, Lucas Castro; Stuart, Silvia Radwanski; Guimarães, Roger Guilherme Rodrigues; Ramos, Clarissa Cerchi Angotti; de Paula, Lucas Assad; de Sales, Camila Pessoa; Chen, André Tsin Chih; Blasbalg, Roberto; Baroni, Ronaldo Hueb

2016-01-01

Purpose To evaluate tumor shrinking kinetics in order to implement image-guided brachytherapy (IGBT) for the treatment of patients with cervix cancer. Material and methods This study has prospectively evaluated tumor shrinking kinetics of thirteen patients with uterine cervix cancer treated with combined chemoradiation. Four high dose rate brachytherapy fractions were delivered during the course of pelvic external beam radiation therapy (EBRT). Magnetic resonance imaging (MRI) exams were acquired at diagnosis (D), first (B1), and third (B3) brachytherapy fractions. Target volumes (GTV and HR-CTV) were calculated by both the ellipsoid formula (VE) and MRI contouring (VC), which were defined by a consensus between at least two radiation oncologists and a pelvic expert radiologist. Results Most enrolled patients had squamous cell carcinoma and FIGO stage IIB disease, and initiated brachytherapy after the third week of pelvic external beam radiation. Gross tumor volume volume reduction from diagnostic MRI to B1 represented 61.9% and 75.2% of the initial volume, when measured by VE and VC, respectively. Only a modest volume reduction (15-20%) was observed from B1 to B3. Conclusions The most expressive tumor shrinking occurred in the first three weeks of oncological treatment and was in accordance with gynecological examination. These findings may help in IGBT implementation. PMID:27648083

Enhanced Ultrasound Visualization of Brachytherapy Seeds by a Novel Magnetically Induced Motion Imaging Method

DTIC Science & Technology

2007-04-01

We report our progress in developing Magnetically Induced Motion Imaging (MIMI) for unambiguous identification and localization brachytherapy seeds ...tail artifacts in segmented seed images. The second is a method for joining ends of seeds in segmented seed images based on the phase of the detected

What to Know about Brachytherapy (A Type of Internal Radiation Therapy)

MedlinePlus

... understand what was going to happen.” About the treatment: ■ ■ Brachytherapy uses radiation to destroy cancer cells and shrink tumors. ■ ■ The ... may have. These differ depending on where the radiation is ... starting treatment. During treatment: ■ ■ Your doctor will place a small ...

Electromagnetic tracking (EMT) technology for improved treatment quality assurance in interstitial brachytherapy.

PubMed

Kellermeier, Markus; Herbolzheimer, Jens; Kreppner, Stephan; Lotter, Michael; Strnad, Vratislav; Bert, Christoph

2017-01-01

Electromagnetic Tracking (EMT) is a novel technique for error detection and quality assurance (QA) in interstitial high dose rate brachytherapy (HDR-iBT). The purpose of this study is to provide a concept for data acquisition developed as part of a clinical evaluation study on the use of EMT during interstitial treatment of breast cancer patients. The stability, accuracy, and precision of EMT-determined dwell positions were quantified. Dwell position reconstruction based on EMT was investigated on CT table, HDR table and PDR bed to examine the influence on precision and accuracy in a typical clinical workflow. All investigations were performed using a precise PMMA phantom. The track of catheters inserted in that phantom was measured by manually inserting a 5 degree of freedom (DoF) sensor while recording the position of three 6DoF fiducial sensors on the phantom surface to correct motion influences. From the corrected data, dwell positions were reconstructed along the catheter's track. The accuracy of the EMT-determined dwell positions was quantified by the residual distances to reference dwell positions after using a rigid registration. Precision and accuracy were investigated for different phantom-table and sensor-field generator (FG) distances. The measured precision of the EMT-determined dwell positions was ≤ 0.28 mm (95th percentile). Stability tests showed a drift of 0.03 mm in the first 20 min of use. Sudden shaking of the FG or (large) metallic objects close to the FG degrade the precision. The accuracy with respect to the reference dwell positions was on all clinical tables < 1 mm at 200 mm FG distance and 120 mm phantom-table distance. Phantom measurements showed that EMT-determined localization of dwell positions in HDR-iBT is stable, precise, and sufficiently accurate for clinical assessment. The presented method may be viable for clinical applications in HDR-iBT, like implant definition, error detection or quantification of uncertainties. Further clinical investigations are needed. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Brachytherapy with Intratumoral Injections of Radiometal-Labeled Polymers That Thermoresponsively Self-Aggregate in Tumor Tissues.

PubMed

Sano, Kohei; Kanada, Yuko; Kanazaki, Kengo; Ding, Ning; Ono, Masahiro; Saji, Hideo

2017-09-01

Brachytherapy is a type of radiotherapy wherein titanium capsules containing therapeutic radioisotopes are implanted within tumor tissues, enabling high-dose radioirradiation to tumor tissues around the seeds. Although marked therapeutic effects have been demonstrated, brachytherapy needs a complicated implantation technique under general anesthesia and the seeds could migrate to other organs. The aim of this study was to establish a novel brachytherapy using biocompatible, injectable thermoresponsive polymers (polyoxazoline [POZ]) labeled with 90 Y, which can self-aggregate above a specific transition temperature (Tt), resulting in long-term intratumoral retention of radioactivity and therapeutic effect. Therefore, we evaluated the tumor retention of radiolabeled POZ derivatives and their therapeutic effects. Methods: Using oxazoline derivatives with ethyl (Et), isopropyl (Isp), and propyl (Pr) side chains, we synthesized EtPOZ, IspPOZ, Isp-PrPOZ (heteropolymer), and PrPOZ and measured their characteristic Tts. The intratumoral retention of 111 In-labeled POZ was evaluated until 7 d after injection in nude mice bearing PC-3 human prostate cancer. The intratumoral localization of 111 In-labeled POZ derivatives was investigated by an autoradiographic study. Furthermore, a therapeutic study using 90 Y-labeled Isp-PrPOZ was performed, and tumor growth and survival rate were evaluated. Results: The Tts of EtPOZ, IspPOZ, Isp-PrPOZ, and PrPOZ (∼20 kDa) were greater than 70°C, 34°C, 25°C, and 19°C, respectively. In the intratumoral injection study, Isp-PrPOZ and PrPOZ (2,000 μM) with Tts lower than tumor temperature (33.5°C under anesthesia) showed a significantly higher retention of radioactivity at 1 d after injection (73.6% and 73.9%, respectively) than EtPOZ (5.6%) and IspPOZ (15.8%). Even at low injected dose (100 μM), Isp-PrPOZ exhibited high retention (68.3% at 1 d). The high level of radioactivity of Isp-PrPOZ was retained in the tumor 7 d after injection (69.5%). The autoradiographic study demonstrated that the radioactivity of 111 In-labeled Isp-PrPOZ and PrPOZ was localized in a small area. In the therapeutic study using 90 Y-labeled Isp-PrPOZ, significant suppression of tumor growth and prolonged survival rate were achieved in an injection dose-dependent manner compared with that observed for the vehicle-injected group and nonradioactive Isp-PrPOZ-injected group. Conclusion: The injectable 90 Y-labeled Isp-PrPOZ was retained for a prolonged period within tumor tissues via self-aggregation and exhibited marked therapeutic effect, suggesting its usefulness for brachytherapy. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borot de Battisti, M; Maenhout, M; Lagendijk, J J W

Purpose: To develop adaptive planning with feedback for MRI-guided focal HDR prostate brachytherapy with a single divergent needle robotic implant device. After each needle insertion, the dwell positions for that needle are calculated and the positioning of remaining needles and dosimetry are both updated based on MR imaging. Methods: Errors in needle positioning may occur due to inaccurate needle insertion (caused by e.g. the needle’s bending) and unpredictable changes in patient anatomy. Consequently, the dose plan quality might dramatically decrease compared to the preplan. In this study, a procedure was developed to re-optimize, after each needle insertion, the remaining needlemore » angulations, source positions and dwell times in order to obtain an optimal coverage (D95% PTV>19 Gy) without exceeding the constraints of the organs at risk (OAR) (D10% urethra<21 Gy, D1cc bladder<12 Gy and D1cc rectum<12 Gy). Complete HDR procedures with 6 needle insertions were simulated for a patient MR-image set with PTV, prostate, urethra, bladder and rectum delineated. Random angulation errors, modeled by a Gaussian distribution (standard deviation of 3 mm at the needle’s tip), were generated for each needle insertion. We compared the final dose parameters for the situations (I) without re-optimization and (II) with the automatic feedback. Results: The computation time of replanning was below 100 seconds on a current desk computer. For the patient tested, a clinically acceptable dose plan was achieved while applying the automatic feedback (median(range) in Gy, D95% PTV: 19.9(19.3–20.3), D10% urethra: 13.4(11.9–18.0), D1cc rectum: 11.0(10.7–11.6), D1cc bladder: 4.9(3.6–6.8)). This was not the case without re-optimization (median(range) in Gy, D95% PTV: 19.4(14.9–21.3), D10% urethra: 12.6(11.0–15.7), D1cc rectum: 10.9(8.9–14.1), D1cc bladder: 4.8(4.4–5.2)). Conclusion: An automatic guidance strategy for HDR prostate brachytherapy was developed to compensate errors in needle positioning and improve the dose distribution. Without re-optimization, target coverage and OAR constraints may not be achieved. M. Borot de Battisti is funded by Philips Medical Systems Nederland B.V.; M. Moerland is principal investigator on a contract funded by Philips Medical Systems Nederland B.V.; G. Hautvast and D. Binnekamp are full-time employees of Philips Medical Systems Nederland B.V.« less

Review of advanced catheter technologies in radiation oncology brachytherapy procedures

PubMed Central

Zhou, Jun; Zamdborg, Leonid; Sebastian, Evelyn

2015-01-01

The development of new catheter and applicator technologies in recent years has significantly improved treatment accuracy, efficiency, and outcomes in brachytherapy. In this paper, we review these advances, focusing on the performance of catheter imaging and reconstruction techniques in brachytherapy procedures using magnetic resonance images and electromagnetic tracking. The accuracy of catheter reconstruction, imaging artifacts, and other notable properties of plastic and titanium applicators in gynecologic treatments are reviewed. The accuracy, noise performance, and limitations of electromagnetic tracking for catheter reconstruction are discussed. Several newly developed applicators for accelerated partial breast irradiation and gynecologic treatments are also reviewed. New hypofractionated high dose rate treatment schemes in prostate cancer and accelerated partial breast irradiation are presented. PMID:26203277

High-dose-rate brachytherapy – a novel treatment approach for primary clear cell adenocarcinoma of male urethra

PubMed Central

Lewis, Shirley; Pal, Mahendra; Bakshi, Ganesh; Ghadi, Yogesh G.; Menon, Santosh; Murthy, Vedang

2015-01-01

The incidence of male urethral cancer is rare with age preponderance of 50 to 60 years. The standard management approach is surgery. Here, we present a novel treatment approach for male urethral cancer. Thirty-six year old male, case of primary clear cell adenocarcinoma of urethra who refused surgery, underwent cystoscopic assisted intraluminal HDR brachytherapy. Patient received a dose of 36 Gy in 9 fractions (4 Gy per fraction) followed by a boost of 24 Gy in 6 fractions. At 11 months post treatment, disease is well controlled with no post treatment toxicity so far. Intraluminal brachytherapy seems to be an effective novel treatment for male urethral cancer. PMID:26207115

Human Error: A Concept Analysis

NASA Technical Reports Server (NTRS)

Hansen, Frederick D.

2007-01-01

Human error is the subject of research in almost every industry and profession of our times. This term is part of our daily language and intuitively understood by most people however, it would be premature to assume that everyone's understanding of human error s the same. For example, human error is used to describe the outcome or consequence of human action, the causal factor of an accident, deliberate violations,a nd the actual action taken by a human being. As a result, researchers rarely agree on the either a specific definition or how to prevent human error. The purpose of this article is to explore the specific concept of human error using Concept Analysis as described by Walker and Avant (1995). The concept of human error is examined as currently used in the literature of a variety of industries and professions. Defining attributes and examples of model, borderline, and contrary cases are described. The antecedents and consequences of human error are also discussed and a definition of human error is offered.

Long-Term Outcomes of Alternative Brachytherapy Techniques for Early Prostate Cancer

DTIC Science & Technology

2007-01-01

Oncol 2003;21:3979-86. 15. Whitmore WF, Jr., Hilaris B, Grabstald H. Retropubic implantation to iodine 125 in the treatment of prostatic cancer. J...brachytherapy and external beam irradiation for clinically localized, high-risk prostatic carcinoma. Int J Radiat Oncol Biol Phys 1996;35:875-9. 29. Stock RG

Magnetic resonance imaging for planning intracavitary brachytherapy for the treatment of locally advanced cervical cancer.

PubMed

Oñate Miranda, M; Pinho, D F; Wardak, Z; Albuquerque, K; Pedrosa, I

2016-01-01

Cervical cancer is the third most common gynecological cancer. Its treatment depends on tumor staging at the time of diagnosis, and a combination of chemotherapy and radiotherapy is the treatment of choice in locally advanced cervical cancers. The combined use of external beam radiotherapy and brachytherapy increases survival in these patients. Brachytherapy enables a larger dose of radiation to be delivered to the tumor with less toxicity for neighboring tissues with less toxicity for neighboring tissues compared to the use of external beam radiotherapy alone. For years, brachytherapy was planned exclusively using computed tomography (CT). The recent incorporation of magnetic resonance imaging (MRI) provides essential information about the tumor and neighboring structures making possible to better define the target volumes. Nevertheless, MRI has limitations, some of which can be compensated for by fusing CT and MRI. Fusing the images from the two techniques ensures optimal planning by combining the advantages of each technique. Copyright © 2015 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

Sci-Thur PM – Brachytherapy 04: Commissioning and Implementation of a Cobalt-60 High Dose Rate Brachytherapy Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dysart, Jonathan

An Eckert & Ziegler Bebig Co0.A86 cobalt 60 high dose rate (HDR) brachytherapy source was commissioned for clinical use. Long-lived Co-60 HDR sources offer potential logistical and economic advantages over Ir-192 sources, and should be considered for low to medium workload brachytherapy departments where modest increases in treatment times are not a factor. In optimized plans, the Co-60 source provides a similar dose distribution to Ir-192 despite the difference in radiation energy. By switching to Co-60, source exchange frequency can be reduced by a factor of 20, resulting in overall financial savings of more than 50% compared to Ir-192 sources.more » In addition, a reduction in Physicist QA workload of roughly 200 hours over the 5 year life of the Co-60 source is also expected. These benefits should be considered against the modest increases in average treatment time compared to those of Ir-192 sources, as well as the centre-specific needs for operating room shielding modification.« less

American Society for Therapeutic Radiology and Oncology (ASTRO) Emerging Technology Committee report on electronic brachytherapy.

PubMed

Park, Catherine C; Yom, Sue S; Podgorsak, Matthew B; Harris, Eleanor; Price, Robert A; Bevan, Alison; Pouliot, Jean; Konski, Andre A; Wallner, Paul E

2010-03-15

The development of novel technologies for the safe and effective delivery of radiation is critical to advancing the field of radiation oncology. The Emerging Technology Committee of the American Society for Therapeutic Radiology and Oncology appointed a Task Group within its Evaluation Subcommittee to evaluate new electronic brachytherapy methods that are being developed for, or are already in, clinical use. The Task Group evaluated two devices, the Axxent Electronic Brachytherapy System by Xoft, Inc. (Fremont, CA), and the Intrabeam Photon Radiosurgery Device by Carl Zeiss Surgical (Oberkochen, Germany). These devices are designed to deliver electronically generated radiation, and because of their relatively low energy output, they do not fall under existing regulatory scrutiny of radioactive sources that are used for conventional radioisotope brachytherapy. This report provides a descriptive overview of the technologies, current and future projected applications, comparison of competing technologies, potential impact, and potential safety issues. The full Emerging Technology Committee report is available on the American Society for Therapeutic Radiology and Oncology Web site. Copyright 2010. Published by Elsevier Inc.

Effect of postoperative brachytherapy and external beam radiotherapy on functional outcomes of immediate facial nerve repair after radical parotidectomy.

PubMed

Hontanilla, Bernardo; Qiu, Shan-Shan; Marré, Diego

2014-01-01

There is much controversy regarding the effect of radiotherapy on facial nerve regeneration. However, the effect of brachytherapy has not been studied. Fifty-three patients underwent total parotidectomy of which 13 were radical with immediate facial nerve repair with sural nerve grafts. Six patients (group 1) did not receive adjuvant treatment whereas 7 patients (group 2) received postoperative brachytherapy plus radiotherapy. Functional outcomes were compared using Facial Clima. Mean percentage of blink recovery was 92.6 ± 4.2 for group 1 and 90.7 ± 5.2 for group 2 (p = .37). Mean percentage of commissural excursion restoration was 78.1 ± 3.5 for group 1 and 74.9 ± 5.9 for group 2 (p = .17). Mean time from surgery to first movement was 5.7 ± 0.9 months for group 1 and 6.3 ± 0.5 months for group 2 (p = .15). Brachytherapy plus radiotherapy does not affect the functional outcomes of immediate facial nerve repair with nerve grafts. Copyright © 2013 Wiley Periodicals, Inc.

American Society for Therapeutic Radiology and Oncology (ASTRO) Emerging Technology Committee Report on Electronic Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Catherine C., E-mail: cpark@radonc.ucsf.ed; Yom, Sue S.; Podgorsak, Matthew B.

The development of novel technologies for the safe and effective delivery of radiation is critical to advancing the field of radiation oncology. The Emerging Technology Committee of the American Society for Therapeutic Radiology and Oncology appointed a Task Group within its Evaluation Subcommittee to evaluate new electronic brachytherapy methods that are being developed for, or are already in, clinical use. The Task Group evaluated two devices, the Axxent Electronic Brachytherapy System by Xoft, Inc. (Fremont, CA), and the Intrabeam Photon Radiosurgery Device by Carl Zeiss Surgical (Oberkochen, Germany). These devices are designed to deliver electronically generated radiation, and because ofmore » their relatively low energy output, they do not fall under existing regulatory scrutiny of radioactive sources that are used for conventional radioisotope brachytherapy. This report provides a descriptive overview of the technologies, current and future projected applications, comparison of competing technologies, potential impact, and potential safety issues. The full Emerging Technology Committee report is available on the American Society for Therapeutic Radiology and Oncology Web site.« less

Evaluation and mitigation of potential errors in radiochromic film dosimetry due to film curvature at scanning.

PubMed

Palmer, Antony L; Bradley, David A; Nisbet, Andrew

2015-03-08

This work considers a previously overlooked uncertainty present in film dosimetry which results from moderate curvature of films during the scanning process. Small film samples are particularly susceptible to film curling which may be undetected or deemed insignificant. In this study, we consider test cases with controlled induced curvature of film and with film raised horizontally above the scanner plate. We also evaluate the difference in scans of a film irradiated with a typical brachytherapy dose distribution with the film naturally curved and with the film held flat on the scanner. Typical naturally occurring curvature of film at scanning, giving rise to a maximum height 1 to 2 mm above the scan plane, may introduce dose errors of 1% to 4%, and considerably reduce gamma evaluation passing rates when comparing film-measured doses with treatment planning system-calculated dose distributions, a common application of film dosimetry in radiotherapy. The use of a triple-channel dosimetry algorithm appeared to mitigate the error due to film curvature compared to conventional single-channel film dosimetry. The change in pixel value and calibrated reported dose with film curling or height above the scanner plate may be due to variations in illumination characteristics, optical disturbances, or a Callier-type effect. There is a clear requirement for physically flat films at scanning to avoid the introduction of a substantial error source in film dosimetry. Particularly for small film samples, a compression glass plate above the film is recommended to ensure flat-film scanning. This effect has been overlooked to date in the literature.

Development of a brachytherapy audit checklist tool.

PubMed

Prisciandaro, Joann; Hadley, Scott; Jolly, Shruti; Lee, Choonik; Roberson, Peter; Roberts, Donald; Ritter, Timothy

2015-01-01

To develop a brachytherapy audit checklist that could be used to prepare for Nuclear Regulatory Commission or agreement state inspections, to aid in readiness for a practice accreditation visit, or to be used as an annual internal audit tool. Six board-certified medical physicists and one radiation oncologist conducted a thorough review of brachytherapy-related literature and practice guidelines published by professional organizations and federal regulations. The team members worked at two facilities that are part of a large, academic health care center. Checklist items were given a score based on their judged importance. Four clinical sites performed an audit of their program using the checklist. The sites were asked to score each item based on a defined severity scale for their noncompliance, and final audit scores were tallied by summing the products of importance score and severity score for each item. The final audit checklist, which is available online, contains 83 items. The audit scores from the beta sites ranged from 17 to 71 (out of 690) and identified a total of 7-16 noncompliance items. The total time to conduct the audit ranged from 1.5 to 5 hours. A comprehensive audit checklist was developed which can be implemented by any facility that wishes to perform a program audit in support of their own brachytherapy program. The checklist is designed to allow users to identify areas of noncompliance and to prioritize how these items are addressed to minimize deviations from nationally-recognized standards. Copyright © 2015 American Brachytherapy Society. All rights reserved.

Estimation of whole-body radiation exposure from brachytherapy for oral cancer using a Monte Carlo simulation

PubMed Central

Ozaki, Y.; Kaida, A.; Miura, M.; Nakagawa, K.; Toda, K.; Yoshimura, R.; Sumi, Y.; Kurabayashi, T.

2017-01-01

Abstract Early stage oral cancer can be cured with oral brachytherapy, but whole-body radiation exposure status has not been previously studied. Recently, the International Commission on Radiological Protection Committee (ICRP) recommended the use of ICRP phantoms to estimate radiation exposure from external and internal radiation sources. In this study, we used a Monte Carlo simulation with ICRP phantoms to estimate whole-body exposure from oral brachytherapy. We used a Particle and Heavy Ion Transport code System (PHITS) to model oral brachytherapy with 192Ir hairpins and 198Au grains and to perform a Monte Carlo simulation on the ICRP adult reference computational phantoms. To confirm the simulations, we also computed local dose distributions from these small sources, and compared them with the results from Oncentra manual Low Dose Rate Treatment Planning (mLDR) software which is used in day-to-day clinical practice. We successfully obtained data on absorbed dose for each organ in males and females. Sex-averaged equivalent doses were 0.547 and 0.710 Sv with 192Ir hairpins and 198Au grains, respectively. Simulation with PHITS was reliable when compared with an alternative computational technique using mLDR software. We concluded that the absorbed dose for each organ and whole-body exposure from oral brachytherapy can be estimated with Monte Carlo simulation using PHITS on ICRP reference phantoms. Effective doses for patients with oral cancer were obtained. PMID:28339846

Novel use of the Contura for high dose rate cranial brachytherapy.

PubMed

Scanderbeg, Daniel J; Alksne, John F; Lawson, Joshua D; Murphy, Kevin T

2011-01-01

A popular choice for treatment of recurrent gliomas was cranial brachytherapy using the GliaSite Radiation Therapy System. However, this device was taken off the market in late 2008, thus leaving a treatment void. This case study presents our experience treating a cranial lesion for the first time using a Contura multilumen, high-dose-rate (HDR) brachytherapy balloon applicator. The patient was a 47-year-old male who was diagnosed with a recurrent right frontal anaplastic oligodendroglioma. Previous radiosurgery made him a good candidate for brachytherapy. An intracavitary HDR balloon brachytherapy device (Contura) was placed in the resection cavity and treated with a single fraction of 20 Gy. The implant, treatment, and removal of the device were all completed without incident. Dosimetry of the device was excellent because the dose conformed very well to the target. V90, V100, V150, and V200 were 98.9%, 95.7%, 27.2, and 8.8 cc, respectively. This patient was treated successfully using the Contura multilumen balloon. Contura was originally designed for deployment in a postlumpectomy breast for treatment by accelerated partial breast irradiation. Being an intracavitary balloon device, its similarity to the GliaSite system makes it a viable replacement candidate. Multiple lumens in the device also make it possible to shape the dose delivered to the target, something not possible before with the GliaSite applicator. Copyright © 2011 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

A gEUD-based inverse planning technique for HDR prostate brachytherapy: Feasibility study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giantsoudi, D.; Department of Radiation Oncology, Francis H. Burr Proton Therapy Center, Boston, Massachusetts 02114; Baltas, D.

2013-04-15

Purpose: The purpose of this work was to study the feasibility of a new inverse planning technique based on the generalized equivalent uniform dose for image-guided high dose rate (HDR) prostate cancer brachytherapy in comparison to conventional dose-volume based optimization. Methods: The quality of 12 clinical HDR brachytherapy implants for prostate utilizing HIPO (Hybrid Inverse Planning Optimization) is compared with alternative plans, which were produced through inverse planning using the generalized equivalent uniform dose (gEUD). All the common dose-volume indices for the prostate and the organs at risk were considered together with radiobiological measures. The clinical effectiveness of the differentmore » dose distributions was investigated by comparing dose volume histogram and gEUD evaluators. Results: Our results demonstrate the feasibility of gEUD-based inverse planning in HDR brachytherapy implants for prostate. A statistically significant decrease in D{sub 10} or/and final gEUD values for the organs at risk (urethra, bladder, and rectum) was found while improving dose homogeneity or dose conformity of the target volume. Conclusions: Following the promising results of gEUD-based optimization in intensity modulated radiation therapy treatment optimization, as reported in the literature, the implementation of a similar model in HDR brachytherapy treatment plan optimization is suggested by this study. The potential of improved sparing of organs at risk was shown for various gEUD-based optimization parameter protocols, which indicates the ability of this method to adapt to the user's preferences.« less

Radiobiological equivalent of low/high dose rate brachytherapy and evaluation of tumor and normal responses to the dose.

PubMed

Manimaran, S

2007-06-01

The aim of this study was to compare the biological equivalent of low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy in terms of the more recent linear quadratic (LQ) model, which leads to theoretical estimation of biological equivalence. One of the key features of the LQ model is that it allows a more systematic radiobiological comparison between different types of treatment because the main parameters alpha/beta and micro are tissue-specific. Such comparisons also allow assessment of the likely change in the therapeutic ratio when switching between LDR and HDR treatments. The main application of LQ methodology, which focuses on by increasing the availability of remote afterloading units, has been to design fractionated HDR treatments that can replace existing LDR techniques. In this study, with LDR treatments (39 Gy in 48 h) equivalent to 11 fractions of HDR irradiation at the experimental level, there are increasing reports of reproducible animal models that may be used to investigate the biological basis of brachytherapy and to help confirm theoretical predictions. This is a timely development owing to the nonavailability of sufficient retrospective patient data analysis. It appears that HDR brachytherapy is likely to be a viable alternative to LDR only if it is delivered without a prohibitively large number of fractions (e.g., fewer than 11). With increased scientific understanding and technological capability, the prospect of a dose equivalent to HDR brachytherapy will allow greater utilization of the concepts discussed in this article.

Salvage/Adjuvant Brachytherapy After Ophthalmic Artery Chemosurgery for Intraocular Retinoblastoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Francis, Jasmine H., E-mail: francij1@mskcc.org; Barker, Christopher A.; Wolden, Suzanne L.

2013-11-01

Purpose: To evaluate the efficacy and toxicity of brachytherapy after ophthalmic artery chemosurgery (OAC) for retinoblastoma. Methods and Materials: This was a single-arm, retrospective study of 15 eyes in 15 patients treated with OAC followed by brachytherapy at (blinded institution) between May 1, 2006, and December 31, 2012, with a median 19 months' follow-up from plaque insertion. Outcome measurements included patient and ocular survival, visual function, and retinal toxicity measured by electroretinogram (ERG). Results: Brachytherapy was used as adjuvant treatment in 2 eyes and as salvage therapy in 13 eyes of which 12 had localized vitreous seeding. No patients developedmore » metastasis or died of retinoblastoma. The Kaplan-Meier estimate of ocular survival was 79.4% (95% confidence interval 48.7%-92.8%) at 18 months. Three eyes were enucleated, and an additional 6 eyes developed out-of-target volume recurrences, which were controlled with additional treatments. Patients with an ocular complication had a mean interval between last OAC and plaque of 2.5 months (SD 2.3 months), which was statistically less (P=.045) than patients without ocular complication who had a mean interval between last OAC and plaque of 6.5 months (SD 4.4 months). ERG responses from pre- versus postplaque were unchanged or improved in more than half the eyes. Conclusions: Brachytherapy following OAC is effective, even in the presence of vitreous seeding; the majority of eyes maintained stable or improved retinal function following treatment, as assessed by ERG.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asadi, Somayeh; Masoudi, Seyed Farhad, E-mail: masoudi@kntu.ac.ir; Shahriari, Majid

In ophthalmic brachytherapy dosimetry, it is common to consider the water phantom as human eye anatomy. However, for better clinical analysis, there is a need for the dose determination in different parts of the eye. In this work, a full human eye is simulated with MCNP-4C code by considering all parts of the eye, i.e., the lens, cornea, retina, choroid, sclera, anterior chamber, optic nerve, and bulk of the eye comprising vitreous body and tumor. The average dose in different parts of this full model of the human eye is determined and the results are compared with the dose calculatedmore » in water phantom. The central axes depth dose and the dose in whole of the tumor for these 2 simulated eye models are calculated as well, and the results are compared.« less

Reduced dose to urethra and rectum with the use of variable needle spacing in prostate brachytherapy: a potential role for robotic technology

PubMed Central

Vyas, Shilpa; Le, Yi; Zhang, Zhe; Armour, Woody

2015-01-01

Purpose Several robotic delivery systems for prostate brachytherapy are under development or in pre-clinical testing. One of the features of robotic brachytherapy is the ability to vary spacing of needles at non-fixed intervals. This feature may play an important role in prostate brachytherapy, which is traditionally template-based with fixed needle spacing of 0.5 cm. We sought to quantify potential reductions in the dose to urethra and rectum by utilizing variable needle spacing, as compared to fixed needle spacing. Material and methods Transrectal ultrasound images from 10 patients were used by 3 experienced planners to create 120 treatment plans. Each planner created 4 plan variations per patient with respect to needle positions: 125I fixed spacing, 125I variable spacing, 103Pd fixed spacing, and 103Pd variable spacing. The primary planning objective was to achieve a prostate V100 of 100% while minimizing dose to urethra and rectum. Results All plans met the objective of achieving prostate V100 of 100%. Combined results for all plans show statistically significant improvements in all assessed dosimetric variables for urethra (Umax, Umean, D30, D5) and rectum (Rmax, Rmean, RV100) when using variable spacing. The dose reductions for mean and maximum urethra dose using variable spacing had p values of 0.011 and 0.024 with 103Pd, and 0.007 and 0.029 with 125I plans. Similarly dose reductions for mean and maximum rectal dose using variable spacing had p values of 0.007 and 0.052 with 103Pd, and 0.012 and 0.037 with 125I plans. Conclusions The variable needle spacing achievable by the use of robotics in prostate brachytherapy allows for reductions in both urethral and rectal planned doses while maintaining prostate dose coverage. Such dosimetric advantages have the potential in translating to significant clinical benefits with the use of robotic brachytherapy. PMID:26622227

Complications of stent placement in patients with esophageal cancer: A systematic review and network meta-analysis

PubMed Central

Doosti-Irani, Amin; Mansournia, Mohammad Ali; Rahimi-Foroushani, Abbas; Haddad, Peiman

2017-01-01

Background Palliative treatments and stents are necessary for relieving dysphagia in patients with esophageal cancer. The aim of this study was to simultaneously compare available treatments in terms of complications. Methods Web of Science, Medline, Scopus, Cochrane Library and Embase were searched. Statistical heterogeneity was assessed using the Chi2 test and was quantified by I2. The results of this study were summarized in terms of Risk Ratio (RR). The random effects model was used to report the results. The rank probability for each treatment was calculated using the p-score. Results Out of 17855 references, 24 RCTs reported complications including treatment related death (TRD), bleeding, stent migration, aspiration, severe pain and fistula formation. In the ranking of treatments, thermal ablative therapy (p-score = 0.82), covered Evolution® stent (p-score = 0.70), brachytherapy (p-score = 0.72) and antireflux stent (p-score = 0.74) were better treatments in the network of TRD. Thermal ablative therapy (p-score = 0.86), the conventional stent (p-score = 0.62), covered Evolution® stent (p-score = 0.96) and brachytherapy (p-score = 0.82) were better treatments in the network of bleeding complications. Covered Evolution® (p-score = 0.78), uncovered (p-score = 0.88) and irradiation stents (p-score = 0.65) were better treatments in network of stent migration complications. In the network of severe pain, Conventional self-expandable nitinol alloy covered stent (p-score = 0.73), polyflex (p-score = 0.79), latex prosthesis (p-score = 0.96) and brachytherapy (p-score = 0.65) were better treatments. Conclusion According to our results, thermal ablative therapy, covered Evolution® stents, brachytherapy, and antireflux stents are associated with a lower risk of TRD. Moreover, thermal ablative therapy, conventional, covered Evolution® and brachytherapy had lower risks of bleeding. Overall, fewer complications were associated with covered Evolution® stent and brachytherapy. PMID:28968416

Monte-Carlo based assessment of MAGIC, MAGICAUG, PAGATUG and PAGATAUG polymer gel dosimeters for ovaries and uterus organ dosimetry in brachytherapy, nuclear medicine and Tele-therapy.

PubMed

Adinehvand, Karim; Rahatabad, Fereidoun Nowshiravan

2018-06-01

Calculation of 3D dose distribution during radiotherapy and nuclear medicine helps us for better treatment of sensitive organs such as ovaries and uterus. In this research, we investigate two groups of normoxic dosimeters based on meta-acrylic acid (MAGIC and MAGICAUG) and polyacrylamide (PAGATUG and PAGATAUG) for brachytherapy, nuclear medicine and Tele-therapy in their sensitive and critical role as organ dosimeters. These polymer gel dosimeters are compared with soft tissue while irradiated by different energy photons in therapeutic applications. This comparison has been simulated by Monte-Carlo based MCNPX code. ORNL phantom-Female has been used to model the critical organs of kidneys, ovaries and uterus. Right kidney is proposed to be the source of irradiation and another two organs are exposed to this irradiation. Effective atomic numbers of soft tissue, MAGIC, MAGICAUG, PAGATUG and PAGATAUG are 6.86, 7.07, 6.95, 7.28, and 7.07 respectively. Results show the polymer gel dosimeters are comparable to soft tissue for using in nuclear medicine and Tele-therapy. Differences between gel dosimeters and soft tissue are defined as the dose responses. This difference is less than 4.1%, 22.6% and 71.9% for Tele-therapy, nuclear medicine and brachytherapy respectively. The results approved that gel dosimeters are the best choice for ovaries and uterus in nuclear medicine and Tele-therapy respectively. Due to the slight difference between the effective atomic numbers of these polymer gel dosimeters and soft tissue, these polymer gels are not suitable for brachytherapy since the dependence of photon interaction to atomic number, for low energy brachytherapy, had been so effective. Also this dependence to atomic number, decrease for photoelectric and increase for Compton. Therefore polymer gel dosimeters are not a good alternative to soft tissue replacement in brachytherapy. Copyright © 2018 Elsevier B.V. All rights reserved.

The adoption of new adjuvant radiation therapy modalities among Medicare beneficiaries with breast cancer: clinical correlates and cost implications.

PubMed

Roberts, Kenneth B; Soulos, Pamela R; Herrin, Jeph; Yu, James B; Long, Jessica B; Dostaler, Edward; Gross, Cary P

2013-04-01

New radiation therapy modalities have broadened treatment options for older women with breast cancer, but it is unclear how clinical factors, geographic region, and physician preference affect the choice of radiation therapy modality. We used the Surveillance, Epidemiology, and End Results-Medicare database to identify women diagnosed with stage I-III breast cancer from 1998 to 2007 who underwent breast-conserving surgery. We assessed the temporal trends in, and costs of, the adoption of intensity modulated radiation therapy (IMRT) and brachytherapy. Using hierarchical logistic regression, we evaluated the relationship between the use of these new modalities and patient and regional characteristics. Of 35,060 patients, 69.9% received conventional external beam radiation therapy (EBRT). Although overall radiation therapy use remained constant, the use of IMRT increased from 0.0% to 12.6% from 1998 to 2007, and brachytherapy increased from 0.7% to 9.0%. The statistical variation in brachytherapy use attributable to the radiation oncologist and geographic region was 41.4% and 9.5%, respectively (for IMRT: 23.8% and 22.1%, respectively). Women undergoing treatment at a free-standing radiation facility were significantly more likely to receive IMRT than were women treated at a hospital-based facility (odds ratio for IMRT vs EBRT: 3.89 [95% confidence interval, 2.78-5.45]). No such association was seen for brachytherapy. The median radiation therapy cost per treated patient increased from $5389 in 2001 to $8539 in 2007. IMRT and brachytherapy use increased substantially from 1998 to 2007; overall, radiation therapy costs increased by more than 50%. Radiation oncologists played an important role in treatment choice for both types of radiation therapy, whereas geographic region played a bigger role in the use of IMRT than brachytherapy. Copyright © 2013 Elsevier Inc. All rights reserved.

Dosimetric impact of an air passage on intraluminal brachytherapy for bronchus cancer.

PubMed

Okamoto, Hiroyuki; Wakita, Akihisa; Nakamura, Satoshi; Nishioka, Shie; Aikawa, Ako; Kato, Toru; Abe, Yoshihisa; Kobayashi, Kazuma; Inaba, Koji; Murakami, Naoya; Itami, Jun

2016-11-01

The brachytherapy dose calculations used in treatment planning systems (TPSs) have conventionally been performed assuming homogeneous water. Using measurements and a Monte Carlo simulation, we evaluated the dosimetric impact of an air passage on brachytherapy for bronchus cancer. To obtain the geometrical characteristics of an air passage, we analyzed the anatomical information from CT images of patients who underwent intraluminal brachytherapy using a high-dose-rate 192 Ir source (MicroSelectron V2r®, Nucletron). Using an ionization chamber, we developed a measurement system capable of measuring the peripheral dose with or without an air cavity surrounding the catheter. Air cavities of five different radii (0.3, 0.5, 0.75, 1.25 and 1.5 cm) were modeled by cylindrical tubes surrounding the catheter. A Monte Carlo code (GEANT4) was also used to evaluate the dosimetric impact of the air cavity. Compared with dose calculations in homogeneous water, the measurements and GEANT4 indicated a maximum overdose of 5-8% near the surface of the air cavity (with the maximum radius of 1.5 cm). Conversely, they indicated a minimum overdose of ~1% in the region 3-5 cm from the cavity surface for the smallest radius of 0.3 cm. The dosimetric impact depended on the size and the distance of the air passage, as well as the length of the treatment region. Based on dose calculations in water, the TPS for intraluminal brachytherapy for bronchus cancer had an unexpected overdose of 3-5% for a mean radius of 0.75 cm. This study indicates the need for improvement in dose calculation accuracy with respect to intraluminal brachytherapy for bronchus cancer. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

American Brachytherapy Society consensus report for accelerated partial breast irradiation using interstitial multicatheter brachytherapy.

PubMed

Hepel, Jaroslaw T; Arthur, Douglas; Shaitelman, Simona; Polgár, Csaba; Todor, Dorin; Zoberi, Imran; Kamrava, Mitchell; Major, Tibor; Yashar, Catheryn; Wazer, David E

To develop a consensus report for the quality practice of accelerated partial breast irradiation (APBI) using interstitial multicatheter brachytherapy (IMB). The American Brachytherapy Society Board appointed an expert panel with clinical and research experience with breast brachytherapy to provide guidance for the current practice of IMB. This report is based on a comprehensive literature review with emphasis on randomized data and expertise of the panel. Randomized trials have demonstrated equivalent efficacy of APBI using IMB compared with whole breast irradiation for select patients with early-stage breast cancer. Several techniques for placement of interstitial catheters are described, and importance of three-dimensional planning with appropriate optimization is reviewed. Optimal target definition is outlined. Commonly used dosing schemas include 50 Gy delivered in pulses of 0.6-0.8 Gy/h using pulsed-dose-rate technique and 34 Gy in 10 fractions, 32 Gy in eight fractions, or 30 Gy in seven fractions using high-dose-rate technique. Potential toxicities and strategies for toxicity avoidance are described in detail. Dosimetric constraints include limiting whole breast volume that receives ≥50% of prescription dose to <60%, skin dose to ≤100% of prescription dose (≤60-70% preferred), chest wall dose to ≤125% of prescription dose, Dose Homogeneity Index to >0.75 (>0.85 preferred), V 150  < 45 cc, and V 200  < 14 cc. Using an optimal implant technique coupled with optimal planning and appropriate dose constraints, a low rate of toxicity and a good-to-excellent cosmetic outcome of ≥90% is expected. IMB is an effective technique to deliver APBI for appropriately selected women with early-stage breast cancer. This consensus report has been created to assist clinicians in the appropriate practice of APBI using IMB. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

The Adoption of New Adjuvant Radiation Therapy Modalities Among Medicare Beneficiaries With Breast Cancer: Clinical Correlates and Cost Implications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, Kenneth B.; Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut; Soulos, Pamela R.

2013-04-01

Purpose: New radiation therapy modalities have broadened treatment options for older women with breast cancer, but it is unclear how clinical factors, geographic region, and physician preference affect the choice of radiation therapy modality. Methods and Materials: We used the Surveillance, Epidemiology, and End Results-Medicare database to identify women diagnosed with stage I-III breast cancer from 1998 to 2007 who underwent breast-conserving surgery. We assessed the temporal trends in, and costs of, the adoption of intensity modulated radiation therapy (IMRT) and brachytherapy. Using hierarchical logistic regression, we evaluated the relationship between the use of these new modalities and patient andmore » regional characteristics. Results: Of 35,060 patients, 69.9% received conventional external beam radiation therapy (EBRT). Although overall radiation therapy use remained constant, the use of IMRT increased from 0.0% to 12.6% from 1998 to 2007, and brachytherapy increased from 0.7% to 9.0%. The statistical variation in brachytherapy use attributable to the radiation oncologist and geographic region was 41.4% and 9.5%, respectively (for IMRT: 23.8% and 22.1%, respectively). Women undergoing treatment at a free-standing radiation facility were significantly more likely to receive IMRT than were women treated at a hospital-based facility (odds ratio for IMRT vs EBRT: 3.89 [95% confidence interval, 2.78-5.45]). No such association was seen for brachytherapy. The median radiation therapy cost per treated patient increased from $5389 in 2001 to $8539 in 2007. Conclusions: IMRT and brachytherapy use increased substantially from 1998 to 2007; overall, radiation therapy costs increased by more than 50%. Radiation oncologists played an important role in treatment choice for both types of radiation therapy, whereas geographic region played a bigger role in the use of IMRT than brachytherapy.« less

Posttraumatic Stress Disorder After High-Dose-Rate Brachytherapy for Cervical Cancer With 2 Fractions in 1 Application Under Spinal/Epidural Anesthesia: Incidence and Risk Factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirchheiner, Kathrin, E-mail: kathrin.kirchheiner@meduniwien.ac.at; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna; Czajka-Pepl, Agnieszka

Purpose: To investigate the psychological consequences of high-dose-rate brachytherapy with 2 fractions in 1 application under spinal/epidural anesthesia in the treatment of locally advanced cervical cancer. Methods and Materials: In 50 patients with locally advanced cervical cancer, validated questionnaires were used for prospective assessment of acute and posttraumatic stress disorder (ASD/PTSD) (Impact of Event Scale–Revision), anxiety/depression (Hospital Anxiety and Depression Scale), quality of life (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30/Cervical Cancer 24), physical functioning (World Health Organization performance status), and pain (visual analogue scale), before and during treatment and 1 week and 3 monthsmore » after treatment. Qualitative interviews were recorded in open format for content analysis. Results: Symptoms of ASD occurred in 30% of patients 1 week after treatment; and of PTSD in 41% 3 months after treatment in association with this specific brachytherapy procedure. Pretreatment predictive variables explain 82% of the variance of PTSD symptoms. Helpful experiences were the support of the treatment team, psychological support, and a positive attitude. Stressful factors were pain, organizational problems during treatment, and immobility between brachytherapy fractions. Conclusions: The specific brachytherapy procedure, as performed in the investigated mono-institutional setting with 2 fractions in 1 application under spinal/epidural anesthesia, bears a considerable risk of traumatization. The source of stress seems to be not the brachytherapy application itself but the maintenance of the applicator under epidural anesthesia in the time between fractions. Patients at risk may be identified before treatment, to offer targeted psycho-social support. The patients' open reports regarding helpful experiences are an encouraging feedback for the treatment team; the reported stressful factors serve as a basis for improvement of patient management, especially regarding pain control.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liao, Y; Turian, J; Templeton, A

Purpose: PET/CT provides important functional information for radiotherapy targeting of cervical cancer. However, repeated PET/CT procedures for external beam and subsequent brachytherapy expose patients to additional radiation and are not cost effective. Our goal is to investigate the possibility of propagating PET-active volumes for brachytherapy procedures through deformable image registration (DIR) of earlier PET/CT and ultimately to minimize the number of PET/CT image sessions required. Methods: Nine cervical cancer patients each received their brachytherapy preplanning PET/CT at the end of EBRT with a Syed template in place. The planning PET/CT was acquired on the day of brachytherapy treatment with themore » actual applicator (Syed or Tandem and Ring) and rigidly registered. The PET/CT images were then deformably registered creating a third (deformed) image set for target prediction. Regions of interest with standardized uptake values (SUV) greater than 65% of maximum SUV were contoured as target volumes in all three sets of PET images. The predictive value of the registered images was evaluated by comparing the preplanning and deformed PET volumes with the planning PET volume using Dice's coefficient (DC) and center-of-mass (COM) displacement. Results: The average DCs were 0.12±0.14 and 0.19±0.16 for rigid and deformable predicted target volumes, respectively. The average COM displacements were 1.9±0.9 cm and 1.7±0.7 cm for rigid and deformable registration, respectively. The DCs were improved by deformable registration, however, both were lower than published data for DIR in other modalities and clinical sites. Anatomical changes caused by different brachytherapy applicators could have posed a challenge to the DIR algorithm. The physiological change from interstitial needle placement may also contribute to lower DC. Conclusion: The clinical use of DIR in PET/CT for cervical cancer brachytherapy appears to be limited by applicator choice and requires further investigation.« less

NEW ULTRA-WIDE-FIELD ANGIOGRAPHIC GRADING SCHEME FOR RADIATION RETINOPATHY AFTER IODINE-125 BRACHYTHERAPY FOR UVEAL MELANOMA.

PubMed

McCannel, Tara A; Kim, EunAh; Kamrava, Mitchell; Lamb, James; Caprioli, Joseph; Yang, Dong; McCannel, Colin A

2017-10-06

Radiation retinopathy remains incompletely characterized and may cause severe vision loss. Ultra-wide-field fluorescein angiography provides a pan-fundus view of vascular alterations caused by radiation treatment and may predict visual and ocular outcomes. We have developed a grading scheme to describe pan-fundus severity and to predict the progression of radiation retinopathy in patients treated for uveal melanoma with iodine-125 brachytherapy. A retrospective review of patients treated with standard iodine-125 brachytherapy for uveal melanoma at the Ophthalmic Oncology Center at the University of California, Los Angeles, who had undergone both baseline and postbrachytherapy ultra-wide-field fluorescein angiography. A grading scheme was devised based on observations of vascular leakage, retinal perfusion status, and retinal proliferation. The correlation of grade severity with patient characteristics, tumor features, visual acuity, optical coherence tomography findings, and neovascular glaucoma was measured with chi-square and one-way analysis of variance analyses. Sixty-seven patients were identified for review. Consistent wide-field angiographic patterns after brachytherapy were observed and graded as follows: Grade 0: normal; Grade 1: late foveal leakage; Grade 2: late peripheral leakage; Grade 3: presence of nonperfusion; and Grade 4: retinal neovascularization. Six eyes (8.9%) were Grade 0; 16 (23.8%) were Grade 1; 25 (37.3%) were Grade 2; 16 (23.4%) were Grade 3; and 4 (6.0%) were Grade 4. Higher grade radiation severity correlated significantly with duration of follow-up (P < 0.02); younger age (P = 0.035); worse visual acuity (P = 0.001); cystoid macular edema or atrophy on optical coherence tomography (P < 0.0001); and neovascular glaucoma (P = 0.003). Wide-field fluorescein angiography revealed distinct fundus-wide patterns of vascular damage, which were progressive in nature in eyes treated with iodine-125 brachytherapy for uveal melanoma and correlated with signs of progressive vascular injury. This grading scheme may have prognostic value to predict the progression of radiation retinopathy and to prognosticate visual outcomes in patients undergoing brachytherapy.

Directional interstitial brachytherapy from simulation to application

NASA Astrophysics Data System (ADS)

Lin, Liyong

Organs at risk (OAR) are sometimes adjacent to or embedded in or overlap with the clinical target volume (CTV) to be treated. The purpose of this PhD study is to develop directionally low energy gamma-emitting interstitial brachytherapy sources. These sources can be applied between OAR to selectively reduce hot spots in the OARs and normal tissues. The reduction of dose over undesired regions can expand patient eligibility or reduce toxicities for the treatment by conventional interstitial brachytherapy. This study covers the development of a directional source from design optimization to construction of the first prototype source. The Monte Carlo code MCNP was used to simulate the radiation transport for the designs of directional sources. We have made a special construction kit to assemble radioactive and gold-shield components precisely into D-shaped titanium containers of the first directional source. Directional sources have a similar dose distribution as conventional sources on the treated side but greatly reduced dose on the shielded side, with a sharp dose gradient between them. A three-dimensional dose deposition kernel for the 125I directional source has been calculated. Treatment plans can use both directional and conventional 125I sources at the same source strength for low-dose-rate (LDR) implants to optimize the dose distributions. For prostate tumors, directional 125I LDR brachytherapy can potentially reduce genitourinary and gastrointestinal toxicities and improve potency preservation for low risk patients. The combination of better dose distribution of directional implants and better therapeutic ratio between tumor response and late reactions enables a novel temporary LDR treatment, as opposed to permanent or high-dose-rate (HDR) brachytherapy for the intermediate risk T2b and high risk T2c tumors. Supplemental external-beam treatments can be shortened with a better brachytherapy boost for T3 tumors. In conclusion, we have successfully finished the design optimization and construction of the first prototype directional source. Potential clinical applications and potential benefits of directional sources have been shown for prostate and breast tumors.

Is modern external beam radiotherapy with androgen deprivation therapy still a viable alternative for prostate cancer in an era of robotic surgery and brachytherapy: a comparison of Australian series.

PubMed

Wilcox, Shea William; Aherne, Noel J; McLachlan, Craig Steven; McKay, Michael J; Last, Andrew J; Shakespeare, Thomas P

2015-02-01

We compare the results of modern external-beam radiotherapy (EBRT), using combined androgen deprivation and dose-escalated intensity-modulated radiotherapy with MRI-CT fusion and daily image guidance with fiducial markers (DE-IG-IMRT), with recently published Australian series of brachytherapy and surgery. Five-year actuarial biochemical disease-free survival (bDFS), metastasis-free survival (MFS) and prostate cancer-specific survival (PCaSS) were calculated for 675 patients treated with DE-IG-IMRT and androgen deprivation therapy (ADT). Patients had intermediate-risk (IR) and high-risk (HR) disease. A search was conducted identifying Australian reports from 2005 onwards of IR and HR patients treated with surgery or brachytherapy, reporting actuarial outcomes at 3 years or later. With a median follow-up of 59 months, our 5-year bDFS was 93.3% overall: 95.5% for IR and 91.3% for HR disease. MFS was 96.9% overall (99.0% IR, 94.9% HR), and PCaSS was 98.8% overall (100% IR, 97.7% HR). Prevalence of Grade 2 genitourinary and gastrointestinal toxicity at 5 years was 1.3% and 1.6%, with 0.3% Grade 3 genitourinary toxicity and no Grade 3 gastrointestinal toxicity. Eight reports of brachytherapy and surgery were identified. The HDR brachytherapy series' median 5-year bDFS was 82.5%, MFS 90.0% and PCaSS 97.9%. One surgical series reported 5-year bDFS of 65.5% for HR patients. One LDR series reported 5-year bDFS of 85% for IR patients. Modern EBRT is at least as effective as modern Australian surgical and brachytherapy techniques. All patients considering treatment for localised prostate cancer should be referred to a radiation oncologist to discuss EBRT as an equivalent option. © 2015 The Royal Australian and New Zealand College of Radiologists.

Automated construction of an intraoperative high-dose-rate treatment plan library for the Varian brachytherapy treatment planning system.

PubMed

Deufel, Christopher L; Furutani, Keith M; Dahl, Robert A; Haddock, Michael G

2016-01-01

The ability to create treatment plans for intraoperative high-dose-rate (IOHDR) brachytherapy is limited by lack of imaging and time constraints. An automated method for creation of a library of high-dose-rate brachytherapy plans that can be used with standard planar applicators in the intraoperative setting is highly desirable. Nonnegative least squares algebraic methods were used to identify dwell time values for flat, rectangular planar applicators. The planar applicators ranged in length and width from 2 cm to 25 cm. Plans were optimized to deliver an absorbed dose of 10 Gy to three different depths from the patient surface: 0 cm, 0.5 cm, and 1.0 cm. Software was written to calculate the optimized dwell times and insert dwell times and positions into a .XML plan template that can be imported into the Varian brachytherapy treatment planning system. The user may import the .XML template into the treatment planning system in the intraoperative setting to match the patient applicator size and prescribed treatment depth. A total of 1587 library plans were created for IOHDR brachytherapy. Median plan generation time was approximately 1 minute per plan. Plan dose was typically 100% ± 1% (mean, standard deviation) of the prescribed dose over the entire length and width of the applicator. Plan uniformity was best for prescription depths of 0 cm and 0.5 cm from the patient surface. An IOHDR plan library may be created using automated methods. Thousands of plan templates may be optimized and prepared in a few hours to accommodate different applicator sizes and treatment depths and reduce treatment planning time. The automated method also enforces dwell time symmetry for symmetrical applicator geometries, which simplifies quality assurance. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

On the Development of a Miniature Neutron Generator for the Brachytherapy Treatment of Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forman, L.

Brachytherapy refers to application of an irradiation source within a tumor. {sup 252}Cf needles used in brachytherapy have been successfully applied to treatment of some of the most virulent cancers but it is doubtful that it will be widely used because of difficulty in dealing with unwanted dose (source cannot be turned off) and in adhering to stringent NRC regulations that have been exacerbated in our post 911 environment. We have been working on the development of a miniature neutron generator with the reaction target placed at the end of a needle (tube) for brachytherapy applications. Orifice geometries are mostmore » amenable, e.g. rectum and cervix, but interstitial use is possible with microsurgery. This paper dicusses the results of a 30 watt DD neutron generator SBU project that demonstrates that sufficient hydrogen isotope current can be delivered down a small diameter needle required for a DT neutron treatment device, and, will summarize the progress of building a commercial device pursued by the All Russian Institute for Automatics (VNIIA) supported by the DOE's Industrial Proliferation Prevention Program (IPP). It is known that most of the fast neutron (FN) beam cancer treatment facilities have been closed down. It appears that the major limitation in the use of FN beams has been damage to healthy tissue, which is relatively insensitive to photons, but this problem is alleviated by brachytherapy. Moreover, recent clinical results indicate that fast neutrons in the boost mode are most highly effective in treating large, hypoxic, and rapidly repopulating diseases. It appears that early boost application of FN may halt angiogenesis (development and repair of tumor vascular system) and shrink the tumor resulting in lower hypoxia. The boost brachytherapy application of a small, low cost neutron generator holds promise of significant contribution to the treatment of cancer.« less

Reduced dose to urethra and rectum with the use of variable needle spacing in prostate brachytherapy: a potential role for robotic technology.

PubMed

Vyas, Shilpa; Le, Yi; Zhang, Zhe; Armour, Woody; Song, Daniel Y

2015-08-01

Several robotic delivery systems for prostate brachytherapy are under development or in pre-clinical testing. One of the features of robotic brachytherapy is the ability to vary spacing of needles at non-fixed intervals. This feature may play an important role in prostate brachytherapy, which is traditionally template-based with fixed needle spacing of 0.5 cm. We sought to quantify potential reductions in the dose to urethra and rectum by utilizing variable needle spacing, as compared to fixed needle spacing. Transrectal ultrasound images from 10 patients were used by 3 experienced planners to create 120 treatment plans. Each planner created 4 plan variations per patient with respect to needle positions: (125)I fixed spacing, (125)I variable spacing, (103)Pd fixed spacing, and (103)Pd variable spacing. The primary planning objective was to achieve a prostate V100 of 100% while minimizing dose to urethra and rectum. All plans met the objective of achieving prostate V100 of 100%. Combined results for all plans show statistically significant improvements in all assessed dosimetric variables for urethra (Umax, Umean, D30, D5) and rectum (Rmax, Rmean, RV100) when using variable spacing. The dose reductions for mean and maximum urethra dose using variable spacing had p values of 0.011 and 0.024 with (103)Pd, and 0.007 and 0.029 with (125)I plans. Similarly dose reductions for mean and maximum rectal dose using variable spacing had p values of 0.007 and 0.052 with (103)Pd, and 0.012 and 0.037 with (125)I plans. The variable needle spacing achievable by the use of robotics in prostate brachytherapy allows for reductions in both urethral and rectal planned doses while maintaining prostate dose coverage. Such dosimetric advantages have the potential in translating to significant clinical benefits with the use of robotic brachytherapy.

Superficial ocular malignancies treated with strontium-90 brachytherapy: long term outcomes

PubMed Central

Gurram, Lavanya; Laskar, Sarbani Ghosh; Chaudhari, Suresh; Khanna, Nehal; Upreti, Rituraj

2015-01-01

Purpose The incidence of conjunctival malignancies is less than 1%. Though surgical excision remains the mainstay of treatment, the incidence of positive surgical margins and local recurrence rates are high, which is approximately up to 33% in negative margins and 56% in positive margins. Radiotherapy reduces the risk of recurrence in these cases. Brachytherapy using β emitters such as strontium-90 (90Sr) is an ideal treatment technique for these tumors with the advantage of treating only a few millimeters of tissue while sparing the underlying normal eye. We report the long term outcomes in the form of local control and late sequelae of patients with conjunctival malignancies treated with 90Sr applicator brachytherapy. Material and methods During 1999-2013, 13 patients with conjunctival tumors, treated using 90Sr brachytherapy were analyzed. Brachytherapy was either in a post-operative adjuvant or in a recurrent setting. Local control (LC), disease free survival (DFS), overall survival (OS), and late sequelae were evaluated. Results The median age at presentation was 47 years (range: 11-71 years). Thirteen patients with 15 tumors were treated. The commonest histology was squamous cell carcinoma. The median dose was 44 Gy over 11 fractions. The median follow up of all the patients was 51 months (range: 3-139 months). The median follow up of patients with carcinoma only was 64 months with a LC and DFS of 90.9% at 5 years. None of the patients developed ≥ grade II Radiation Therapy Oncology Group (RTOG) acute toxicities. One patient developed a focal scar and another developed corneal opacification at the limbus. Vision was not impaired in any of the patients. Conclusions Strontium-90 brachytherapy used in early invasive conjunctival malignancies as an adjunct to surgery in primary and recurrent settings, results in optimal disease control and ocular functional outcomes. PMID:26622243

A technical evaluation of the Nucletron FIRST system: conformance of a remote afterloading brachytherapy seed implantation system to manufacturer specifications and AAPM Task Group report recommendations.

PubMed

Rivard, Mark J; Evans, Dee-Ann Radford; Kay, Ian

2005-01-01

The Fully Integrated Real-time Seed Treatment (FIRST) system by Nucletron has been available in Europe since November 2001 and is being used more and more in Canada and the United States. Like the conventional transrectal ultrasound implant procedure, the FIRST system utilizes an ultrasound probe, needles, and brachytherapy seeds. However, this system is unique in that it (1) utilizes a low-dose-rate brachytherapy seed remote afterloader (the seedSelectron), (2) utilizes 3D image reconstruction acquired from electromechanically controlled, nonstepping rotation of the ultrasound probe, (3) integrates the control of a remote afterloader with electromechanical control of the ultrasound probe for integrating the clinical procedure into a single system, and (4) automates the transfer of planning information and seed delivery to improve quality assurance and radiation safety. This automated delivery system is specifically intended to address reproducibility and accuracy of seed positioning during implantation. The FIRST computer system includes two software environments: SPOT PRO and seedSelectron; both are used to facilitate treatment planning and brachytherapy seed implantation from beginning to completion of the entire procedure. In addition to these features, the system is reported to meet certain product specifications for seed delivery positioning accuracy and reproducibility, seed calibration accuracy and reliability, and brachytherapy dosimetry calculations. Consequently, a technical evaluation of the FIRST system was performed to determine adherence to manufacturer specifications and to the American Association of Physicists in Medicine (AAPM) Task Group Reports 43, 53, 56, 59, and 64 and recommendations of the American Brachytherapy Society (ABS). The United States Nuclear Regulatory Commission (NRC) has recently added Licensing Guidance for the seedSelectron system under 10 CFR 35.1000. Adherence to licensing guidance is made by referencing applicable AAPM Task Group recommendations. In general, results of this evaluation indicated that the system met its claimed specifications as well as the applicable recommendations outlined in the AAPM and ABS reports.

Robotic Needle Guide for Prostate Brachytherapy: Clinical Testing of Feasibility and Performance

PubMed Central

Song, Danny Y; Burdette, Everette C; Fiene, Jonathan; Armour, Elwood; Kronreif, Gernot; Deguet, Anton; Zhang, Zhe; Iordachita, Iulian; Fichtinger, Gabor; Kazanzides, Peter

2010-01-01

Purpose Optimization of prostate brachytherapy is constrained by tissue deflection of needles and fixed spacing of template holes. We developed and clinically tested a robotic guide towards the goal of allowing greater freedom of needle placement. Methods and Materials The robot consists of a small tubular needle guide attached to a robotically controlled arm. The apparatus is mounted and calibrated to operate in the same coordinate frame as a standard template. Translation in x and y directions over the perineum ±40mm are possible. Needle insertion is performed manually. Results Five patients were treated in an IRB-approved study. Confirmatory measurements of robotic movements for initial 3 patients using infrared tracking showed mean error of 0.489 mm (SD 0.328 mm). Fine adjustments in needle positioning were possible when tissue deflection was encountered; adjustments were performed in 54/179 (30.2%) needles placed, with 36/179 (20.1%) adjustments of > 2mm. Twenty-seven insertions were intentionally altered to positions between the standard template grid to improve the dosimetric plan or avoid structures such as pubic bone and blood vessels. Conclusions Robotic needle positioning provided a means of compensating for needle deflections as well as the ability to intentionally place needles into areas between the standard template holes. To our knowledge, these results represent the first clinical testing of such a system. Future work will be incorporation of direct control of the robot by the physician, adding software algorithms to help avoid robot collisions with the ultrasound, and testing the angulation capability in the clinical setting. PMID:20729152

Iodine 125 Brachytherapy With Vitrectomy and Silicone Oil in the Treatment of Uveal Melanoma: 1-to-1 Matched Case-Control Series

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCannel, Tara A., E-mail: TMcCannel@jsei.ucla.edu; McCannel, Colin A.

Purpose: We initially reported the radiation-attenuating effect of silicone oil 1000 centistokes for iodine 125. The purpose of this report was to compare the clinical outcomes in case patients who had iodine 125 brachytherapy with vitrectomy and silicone oil 1000 centistokes with the outcomes in matched control patients who underwent brachytherapy alone. Methods and Materials: Consecutive patients with uveal melanoma who were treated with iodine 125 plaque brachytherapy and vitrectomy with silicone oil with minimum 1-year follow-up were included. Control patients who underwent brachytherapy alone were matched for tumor size, location, and sex. Baseline patient and tumor characteristics and tumor response tomore » radiation, final visual acuity, macular status, central macular thickness by ocular coherence tomography (OCT), cataract progression, and metastasis at last follow-up visit were compared. Surgical complications were also determined. Results: Twenty case patients met the inclusion criteria. The average follow-up time was 22.1 months in case patients and 19.4 months in control patients. The final logMAR vision was 0.81 in case patients and 1.1 in control patients (P=.071); 8 case patients and 16 control patients had abnormal macular findings (P=.011); and the average central macular thickness by OCT was 293.2 μm in case patients and 408.5 μm in control patients (P=.016). Eleven case patients (55%) and 1 control patient (5%) had required cataract surgery at last follow-up (P=.002). Four patients in the case group and 1 patient in the control group experienced metastasis (P=.18). Among the cases, intraoperative retinal tear occurred in 3 patients; total serous retinal detachment and macular hole developed in 1 case patient each. There was no case of rhegmatogenous retinal detachment, treatment failure, or local tumor dissemination in case patients or control patients. Conclusions: With up to 3 years of clinical follow-up, silicone oil during brachytherapy for the treatment of uveal melanoma resulted in fewer abnormal maculas, lower central macular thickness on OCT, and a trend toward better final visual acuity in comparison with matched control patients who underwent brachytherapy alone.« less

AAPM and GEC-ESTRO guidelines for image-guided robotic brachytherapy: Report of Task Group 192

DOE Office of Scientific and Technical Information (OSTI.GOV)

Podder, Tarun K., E-mail: tarun.podder@uhhospitals.org; Beaulieu, Luc; Caldwell, Barrett

In the last decade, there have been significant developments into integration of robots and automation tools with brachytherapy delivery systems. These systems aim to improve the current paradigm by executing higher precision and accuracy in seed placement, improving calculation of optimal seed locations, minimizing surgical trauma, and reducing radiation exposure to medical staff. Most of the applications of this technology have been in the implantation of seeds in patients with early-stage prostate cancer. Nevertheless, the techniques apply to any clinical site where interstitial brachytherapy is appropriate. In consideration of the rapid developments in this area, the American Association of Physicistsmore » in Medicine (AAPM) commissioned Task Group 192 to review the state-of-the-art in the field of robotic interstitial brachytherapy. This is a joint Task Group with the Groupe Européen de Curiethérapie-European Society for Radiotherapy and Oncology (GEC-ESTRO). All developed and reported robotic brachytherapy systems were reviewed. Commissioning and quality assurance procedures for the safe and consistent use of these systems are also provided. Manual seed placement techniques with a rigid template have an estimated in vivo accuracy of 3–6 mm. In addition to the placement accuracy, factors such as tissue deformation, needle deviation, and edema may result in a delivered dose distribution that differs from the preimplant or intraoperative plan. However, real-time needle tracking and seed identification for dynamic updating of dosimetry may improve the quality of seed implantation. The AAPM and GEC-ESTRO recommend that robotic systems should demonstrate a spatial accuracy of seed placement ≤1.0 mm in a phantom. This recommendation is based on the current performance of existing robotic brachytherapy systems and propagation of uncertainties. During clinical commissioning, tests should be conducted to ensure that this level of accuracy is achieved. These tests should mimic the real operating procedure as closely as possible. Additional recommendations on robotic brachytherapy systems include display of the operational state; capability of manual override; documented policies for independent check and data verification; intuitive interface displaying the implantation plan and visualization of needle positions and seed locations relative to the target anatomy; needle insertion in a sequential order; robot–clinician and robot–patient interactions robustness, reliability, and safety while delivering the correct dose at the correct site for the correct patient; avoidance of excessive force on radioactive sources; delivery confirmation of the required number or position of seeds; incorporation of a collision avoidance system; system cleaning, decontamination, and sterilization procedures. These recommendations are applicable to end users and manufacturers of robotic brachytherapy systems.« less

Dose rate in brachytherapy using after-loading machine: pulsed or high-dose rate?

PubMed

Hannoun-Lévi, J-M; Peiffert, D

2014-10-01

Since February 2014, it is no longer possible to use low-dose rate 192 iridium wires due to the end of industrial production of IRF1 and IRF2 sources. The Brachytherapy Group of the French society of radiation oncology (GC-SFRO) has recommended switching from iridium wires to after-loading machines. Two types of after-loading machines are currently available, based on the dose rate used: pulsed-dose rate or high-dose rate. In this article, we propose a comparative analysis between pulsed-dose rate and high-dose rate brachytherapy, based on biological, technological, organizational and financial considerations. Copyright © 2014 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

High Intensity Focused Ultrasound (HIFU) as a Salvage Treatment for Recurrent Prostate Cancer after Brachytherapy — a Feasibility Study

NASA Astrophysics Data System (ADS)

Chapman, Alexander T.; Rivens, Ian H.; Thompson, Alan C.; ter Haar, Gail R.

2007-05-01

HIFU may be an effective salvage treatment for patients who develop local recurrence after permanent low-dose brachytherapy. It has been suggested that the presence of seeds in the prostate may obstruct the HIFU beam or alter the heating characteristics of the prostate tissue. Acoustic field measurements were made using a membrane hydrophone and lesioning experiments were carried out in ex vivo bovine liver. These revealed a significant effect of the seeds on the HIFU focal region as well as a reduction in lesion length when seeds were placed in a pre-focal position. Further work is needed to evaluate the full effects of implanted brachytherapy seeds on the clinical delivery of HIFU.

Plastic optical fibre sensor for in-vivo radiation monitoring during brachytherapy

NASA Astrophysics Data System (ADS)

Woulfe, P.; Sullivan, F. J.; Lewis, E.; O'Keeffe, S.

2015-09-01

An optical fibre sensor is presented for applications in real-time in-vivo monitoring of the radiation dose a cancer patient receives during seed implantation in Brachytherapy. The sensor is based on radioluminescence whereby radiation sensitive scintillation material is embedded in the core of a 1mm plastic optical fibre. Three scintillation materials are investigated: thallium-doped caesium iodide (CsI:Tl), terbium-doped gadolinium oxysulphide (Gd2O2S:Tb) and europium-doped lanthanum oxysulphide (La2O2S:Eu). Terbium-doped gadolinium oxysulphide was identified as being the most suitable scintillator and further testing demonstrates its measureable response to different activities of Iodine-125, the radio-active source commonly used in Brachytherapy for treating prostate cancer.

[Guidelines for external radiotherapy and brachytherapy: introduction to the 2nd edition. Société française de radiothérapie oncologique (SFRO)].

PubMed

Mahé, M-A; Barillot, I; Chauvet, B

2014-10-01

In 2007, a first edition was published with the objective to produce guidelines for optimization, harmonization and homogenization of practices in external radiation therapy in France. The second edition, including brachytherapy, has the same objective and takes into account recent technologic improvements (intensity modulation radiation therapy, stereotactic radiotherapy, and 3-dimension brachytherapy) and recent results of the literature. The first part is about daily use of general principles (quality, security, image-guided radiation therapy) and the second is to describe each step of treatment of main cancers. Copyright © 2014 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Photon counting readout pixel array in 0.18-μm CMOS technology for on-line gamma-ray imaging of 103palladium seeds for permanent breast seed implant (PBSI) brachytherapy

NASA Astrophysics Data System (ADS)

Goldan, A. H.; Karim, K. S.; Reznik, A.; Caldwell, C. B.; Rowlands, J. A.

2008-03-01

Permanent breast seed implant (PBSI) brachytherapy technique was recently introduced as an alternative to high dose rate (HDR) brachytherapy and involves the permanent implantation of radioactive 103Palladium seeds into the surgical cavity of the breast for cancer treatment. To enable accurate seed implantation, this research introduces a gamma camera based on a hybrid amorphous selenium detector and CMOS readout pixel architecture for real-time imaging of 103Palladium seeds during the PBSI procedure. A prototype chip was designed and fabricated in 0.18-μm n-well CMOS process. We present the experimental results obtained from this integrated photon counting readout pixel.

Metal artifact reduction in MRI-based cervical cancer intracavitary brachytherapy

NASA Astrophysics Data System (ADS)

Rao, Yuan James; Zoberi, Jacqueline E.; Kadbi, Mo; Grigsby, Perry W.; Cammin, Jochen; Mackey, Stacie L.; Garcia-Ramirez, Jose; Goddu, S. Murty; Schwarz, Julie K.; Gach, H. Michael

2017-04-01

Magnetic resonance imaging (MRI) plays an increasingly important role in brachytherapy planning for cervical cancer. Yet, metal tandem, ovoid intracavitary applicators, and fiducial markers used in brachytherapy cause magnetic susceptibility artifacts in standard MRI. These artifacts may impact the accuracy of brachytherapy treatment and the evaluation of tumor response by misrepresenting the size and location of the metal implant, and distorting the surrounding anatomy and tissue. Metal artifact reduction sequences (MARS) with high bandwidth RF selective excitations and turbo spin-echo readouts were developed for MRI of orthopedic implants. In this study, metal artifact reduction was applied to brachytherapy of cervical cancer using the orthopedic metal artifact reduction (O-MAR) sequence. O-MAR combined MARS features with view angle tilting and slice encoding for metal artifact correction (SEMAC) to minimize in-plane and through-plane susceptibility artifacts. O-MAR improved visualization of the tandem tip on T2 and proton density weighted (PDW) imaging in phantoms and accurately represented the diameter of the tandem. In a pilot group of cervical cancer patients (N  =  7), O-MAR significantly minimized the blooming artifact at the tip of the tandem in PDW MRI. There was no significant difference observed in artifact reduction between the weak (5 kHz, 7 z-phase encodes) and medium (10 kHz, 13 z-phase encodes) SEMAC settings. However, the weak setting allowed a significantly shorter acquisition time than the medium setting. O-MAR also reduced susceptibility artifacts associated with metal fiducial markers so that they appeared on MRI at their true dimensions.

Estimation of whole-body radiation exposure from brachytherapy for oral cancer using a Monte Carlo simulation.

PubMed

Ozaki, Y; Watanabe, H; Kaida, A; Miura, M; Nakagawa, K; Toda, K; Yoshimura, R; Sumi, Y; Kurabayashi, T

2017-07-01

Early stage oral cancer can be cured with oral brachytherapy, but whole-body radiation exposure status has not been previously studied. Recently, the International Commission on Radiological Protection Committee (ICRP) recommended the use of ICRP phantoms to estimate radiation exposure from external and internal radiation sources. In this study, we used a Monte Carlo simulation with ICRP phantoms to estimate whole-body exposure from oral brachytherapy. We used a Particle and Heavy Ion Transport code System (PHITS) to model oral brachytherapy with 192Ir hairpins and 198Au grains and to perform a Monte Carlo simulation on the ICRP adult reference computational phantoms. To confirm the simulations, we also computed local dose distributions from these small sources, and compared them with the results from Oncentra manual Low Dose Rate Treatment Planning (mLDR) software which is used in day-to-day clinical practice. We successfully obtained data on absorbed dose for each organ in males and females. Sex-averaged equivalent doses were 0.547 and 0.710 Sv with 192Ir hairpins and 198Au grains, respectively. Simulation with PHITS was reliable when compared with an alternative computational technique using mLDR software. We concluded that the absorbed dose for each organ and whole-body exposure from oral brachytherapy can be estimated with Monte Carlo simulation using PHITS on ICRP reference phantoms. Effective doses for patients with oral cancer were obtained. © The Author 2017. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

The effects of metallic implants on electroporation therapies: feasibility of irreversible electroporation for brachytherapy salvage.

PubMed

Neal, Robert E; Smith, Ryan L; Kavnoudias, Helen; Rosenfeldt, Franklin; Ou, Ruchong; Mclean, Catriona A; Davalos, Rafael V; Thomson, Kenneth R

2013-12-01

Electroporation-based therapies deliver brief electric pulses into a targeted volume to destabilize cellular membranes. Nonthermal irreversible electroporation (IRE) provides focal ablation with effects dependent on the electric field distribution, which changes in heterogeneous environments. It should be determined if highly conductive metallic implants in targeted regions, such as radiotherapy brachytherapy seeds in prostate tissue, will alter treatment outcomes. Theoretical and experimental models determine the impact of prostate brachytherapy seeds on IRE treatments. This study delivered IRE pulses in nonanimal, as well as in ex vivo and in vivo tissue, with and in the absence of expired radiotherapy seeds. Electrical current was measured and lesion dimensions were examined macroscopically and with magnetic resonance imaging. Finite-element treatment simulations predicted the effects of brachytherapy seeds in the targeted region on electrical current, electric field, and temperature distributions. There was no significant difference in electrical behavior in tissue containing a grid of expired radiotherapy seeds relative to those without seeds for nonanimal, ex vivo, and in vivo experiments (all p > 0.1). Numerical simulations predict no significant alteration of electric field or thermal effects (all p > 0.1). Histology showed cellular necrosis in the region near the electrodes and seeds within the ablation region; however, there were no seeds beyond the ablation margins. This study suggests that electroporation therapies can be implemented in regions containing small metallic implants without significant changes to electrical and thermal effects relative to use in tissue without the implants. This supports the ability to use IRE as a salvage therapy option for brachytherapy.

Endoresection with adjuvant ruthenium brachytherapy for selected uveal melanoma patients - the Tuebingen experience.

PubMed

Süsskind, Daniela; Dürr, Carina; Paulsen, Frank; Kaulich, Theodor; Bartz-Schmidt, Karl U

2017-12-01

To evaluate the treatment of selected patients with uveal melanoma with endoresection and adjuvant ruthenium brachytherapy. Thirty-five patients with uveal melanoma not suitable for ruthenium plaque monotherapy were treated with endoresection and adjuvant ruthenium brachytherapy between January 2001 and October 2013. Recurrence-free survival, globe retention, course of visual acuity (VA), occurrence of therapy-related complications and metastasis-free and overall survival were analysed retrospectively. Eight patients (22.9%) had a tumour recurrence after a median follow-up of 49.5 months (range: 21-134 months). Enucleation was necessary in eight patients. Thirty-two patients (91%) had a loss of VA with a median loss of nine lines (range: 0 to -39 lines); VA was stable in three patients and no patients had a gain in VA. Four patients (11.4%) developed radiation retinopathy. Metastases were detected in seven patients (20.0%) during follow-up. The occurrence of metastasis was significantly associated with monosomy 3 (p < 0.0001). Twenty-four patients (68.6%) were alive at the end of follow-up. Five patients (14.3%) died because of uveal melanoma (UM) metastasis. Endoresection with adjuvant ruthenium brachytherapy is an option for selected patients with UM who cannot be treated with brachytherapy as monotherapy. About two-thirds of eyes can be retained long term without recurrences. Visual acuity cannot be maintained in most cases, and may even decrease considerably. Radiation complications are comparatively rare and not a significant problem. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Practice patterns of radiotherapy in cervical cancer among member groups of the Gynecologic Cancer Intergroup (GCIG).

PubMed

Gaffney, David K; Du Bois, Andreas; Narayan, Kailash; Reed, Nick; Toita, Takafumi; Pignata, Sandro; Blake, Peter; Portelance, Lorraine; Sadoyze, Azmat; Pötter, Richard; Colombo, Alessandro; Randall, Marcus; Mirza, Mansoor R; Trimble, Edward L

2007-06-01

The aim of this study was to describe radiotherapeutic practice of the treatment of cervical cancer in member groups of the Gynecologic Cancer Intergroup (GCIG). A survey was developed and distributed to the members of the GCIG focusing on details of radiotherapy practice. Different scenarios were queried including advanced cervical cancer, postoperative patients, and para-aortic-positive lymph node cases. Items focused on indications for radiation therapy, radiation fields, dose, use of chemotherapy, brachytherapy and others. The cooperative groups from North America were compared with the other groups to evaluate potential differences in radiotherapy doses. A total of 39 surveys were returned from 13 different cooperative groups. For the treatment of advanced cervical cancer, external beam pelvic doses and total doses to point A were 47 + 3.5 Gy (mean + SD) and 79.1 + 7.9 Gy, respectively. Point A doses were not different between the North American cooperative groups compared with the others (p = 0.103). All groups used concomitant chemotherapy, with 30 of 36 respondents using weekly cisplatin. Of 33 respondents, 31 intervened for a low hemoglobin level. For a para-aortic field, the upper border was most commonly (15 of 24) at the T12-L1 interspace. Maintenance chemotherapy (after radiotherapy) was not performed by 68% of respondents. For vaginal brachytherapy after hysterectomy, 23 groups performed HDR brachytherapy and four groups used LDR brachytherapy. In the use of brachytherapy, there was no uniformity in dose prescription. Radiotherapy practices among member groups of the GCIG are similar in terms of both doses and use of chemotherapy.

Impact of point A asymmetry on local control and survival for low dose-rate (LDR) brachytherapy in cervical cancer.

PubMed

Opfermann, Krisha J; Wahlquist, Amy; Watkins, John; Kohler, Matthew; Jenrette, Joseph

2012-03-01

To evaluate whether Point A asymmetry in low dose-rate (LDR) brachytherapy is associated with local control (LC), disease-free survival (DFS) and/or overall survival (OS). A retrospective analysis of disease control and survival outcomes was conducted for patients who underwent LDR brachytherapy for advanced cervical cancer. Institutional protocol entailed concurrent chemotherapy and whole pelvis radiotherapy (WPRT) over 5 weeks, followed by placement of Fletcher-Suit tandem and colpostat applicators at weeks 6 and 8. Objective Point A doses, 80-85 Gy, were accomplished by placement of Cesium-137 (Cs-137) sources. Cox proportional hazards regression models were used to assess associations between disease control and survival endpoints with variables of interest. The records of 50 patients with FIGO stage IB1-IVA cervical cancer undergoing LDR brachytherapy at our institution were identified. Thirty of these patients had asymmetry > 2.5%, and 11 patients had asymmetry > 5%. At a median survivor follow-up of 20.25 months, 15 patients had experienced disease failure (including 5 cervical/vaginal apex only failures and 2 failures encompassing the local site). Right/left dose asymmetry at Point A was associated with statistically significantly inferior LC (p = 0.035) and inferior DFS (p = 0.011) for patients with mean Point A dose of > 80 Gy. Insufficient evidence existed to conclude an association with OS. LDR brachytherapy may be associated with clinically significant dose asymmetry. The present study demonstrates that patients with Point A asymmetry have a higher risk of failure for DFS and LC.

Impact of point A asymmetry on local control and survival for low dose-rate (LDR) brachytherapy in cervical cancer

PubMed Central

Wahlquist, Amy; Watkins, John; Kohler, Matthew; Jenrette, Joseph

2012-01-01

Purpose To evaluate whether Point A asymmetry in low dose-rate (LDR) brachytherapy is associated with local control (LC), disease-free survival (DFS) and/or overall survival (OS). Material and methods A retrospective analysis of disease control and survival outcomes was conducted for patients who underwent LDR brachytherapy for advanced cervical cancer. Institutional protocol entailed concurrent chemotherapy and whole pelvis radiotherapy (WPRT) over 5 weeks, followed by placement of Fletcher-Suit tandem and colpostat applicators at weeks 6 and 8. Objective Point A doses, 80-85 Gy, were accomplished by placement of Cesium-137 (Cs-137) sources. Cox proportional hazards regression models were used to assess associations between disease control and survival endpoints with variables of interest. Results The records of 50 patients with FIGO stage IB1-IVA cervical cancer undergoing LDR brachytherapy at our institution were identified. Thirty of these patients had asymmetry > 2.5%, and 11 patients had asymmetry > 5%. At a median survivor follow-up of 20.25 months, 15 patients had experienced disease failure (including 5 cervical/vaginal apex only failures and 2 failures encompassing the local site). Right/left dose asymmetry at Point A was associated with statistically significantly inferior LC (p = 0.035) and inferior DFS (p = 0.011) for patients with mean Point A dose of > 80 Gy. Insufficient evidence existed to conclude an association with OS. Conclusions LDR brachytherapy may be associated with clinically significant dose asymmetry. The present study demonstrates that patients with Point A asymmetry have a higher risk of failure for DFS and LC. PMID:23346133

Clinical outcome of high-dose-rate interstitial brachytherapy in vulvar cancer: A single institutional experience.

PubMed

Mahantshetty, Umesh; Naga, Pushpa; Engineer, Reena; Sastri, Supriya; Ghadi, Yogesh; Upreti, Udita; Somesan, Vijaya; Kadam, Sudarshan; Kohle, Satish; Deshpande, Deepak; Shrivastava, Shyam Kishore

With an aim to evaluate and report high dose date interstitial brachytherapy (HDR-ISBT) in vulvar cancers, we undertook this retrospective analysis. Histologically proven vulvar cancers treated with HDR-ISBT between 2001 and 2016 were analyzed. Radiotherapy details, clinical outcome in terms of local control rates, survivals, and toxicities were evaluated. A total of 38 patients received HDR-ISBT, with definitive radiation in 29 (76.3%), adjuvant postoperative in six (15.8%) and salvage radiation in three (7.9%) patients. Of them, 29 patients received brachytherapy boost and nine patients ISBT alone. BT procedure included freehand plastic tube technique in 23 (single [n = 5] or multiple plane [n = 18]), 13 patients with template based and two patients combined approach. Patients with brachytherapy alone received median EQD2 of 38.4 Gy 10 (35.5-46.7 Gy 10 ), as boost received median 23.3 Gy 10 (13-37.3 Gy 10 ). At 3-month post-treatment response evaluation, 30 patients achieved clinically complete response, two patients partial response and six maintained postoperative status. With a median follow-up of 30 months, 29 (76.3%) were disease free, and 9 (23.7%) patients had relapsed disease with four patients expired due to disease and two died of other causes. The 5-year overall survival, disease free survival, and local control rates were 82%, 51%, and 77%, respectively. HDR-ISBT in vulvar cancer is a feasible and a viable option with acceptable and comparable outcomes. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Dosimetric impact of contouring and image registration variability on dynamic 125I prostate brachytherapy.

PubMed

Westendorp, Hendrik; Surmann, Kathrin; van de Pol, Sandrine M G; Hoekstra, Carel J; Kattevilder, Robert A J; Nuver, Tonnis T; Moerland, Marinus A; Slump, Cornelis H; Minken, André W

The quality of permanent prostate brachytherapy can be increased by addition of imaging modalities in the intraoperative procedure. This addition involves image registration, which inherently has inter- and intraobserver variabilities. We sought to quantify the inter- and intraobserver variabilities in geometry and dosimetry for contouring and image registration and analyze the results for our dynamic 125 I brachytherapy procedure. Five observers contoured 11 transrectal ultrasound (TRUS) data sets three times and 11 CT data sets one time. The observers registered 11 TRUS and MRI data sets to cone beam CT (CBCT) using fiducial gold markers. Geometrical and dosimetrical inter- and intraobserver variabilities were assessed. For the contouring study, structures were subdivided into three parts along the craniocaudal axis. We analyzed 165 observations. Interobserver geometrical variability for prostate was 1.1 mm, resulting in a dosimetric variability of 1.6% for V 100 and 9.3% for D 90 . The geometric intraobserver variability was 0.6 mm with a V 100 of 0.7% and D 90 of 1.1%. TRUS-CBCT registration showed an interobserver variability in V 100 of 2.0% and D 90 of 3.1%. Intraobserver variabilities were 0.9% and 1.6%, respectively. For MRI-CBCT registration, V 100 and D 90 were 1.3% and 2.1%. Intraobserver variabilities were 0.7% and 1.1% for the same. Prostate dosimetry is affected by interobserver contouring and registration variability. The observed variability is smaller than underdosages that are adapted during our dynamic brachytherapy procedure. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Human Error In Complex Systems

NASA Technical Reports Server (NTRS)

Morris, Nancy M.; Rouse, William B.

1991-01-01

Report presents results of research aimed at understanding causes of human error in such complex systems as aircraft, nuclear powerplants, and chemical processing plants. Research considered both slips (errors of action) and mistakes (errors of intention), and influence of workload on them. Results indicated that: humans respond to conditions in which errors expected by attempting to reduce incidence of errors; and adaptation to conditions potent influence on human behavior in discretionary situations.

A semiautomatic segmentation method for prostate in CT images using local texture classification and statistical shape modeling.

PubMed

Shahedi, Maysam; Halicek, Martin; Guo, Rongrong; Zhang, Guoyi; Schuster, David M; Fei, Baowei

2018-06-01

Prostate segmentation in computed tomography (CT) images is useful for treatment planning and procedure guidance such as external beam radiotherapy and brachytherapy. However, because of the low, soft tissue contrast of CT images, manual segmentation of the prostate is a time-consuming task with high interobserver variation. In this study, we proposed a semiautomated, three-dimensional (3D) segmentation for prostate CT images using shape and texture analysis and we evaluated the method against manual reference segmentations. The prostate gland usually has a globular shape with a smoothly curved surface, and its shape could be accurately modeled or reconstructed having a limited number of well-distributed surface points. In a training dataset, using the prostate gland centroid point as the origin of a coordination system, we defined an intersubject correspondence between the prostate surface points based on the spherical coordinates. We applied this correspondence to generate a point distribution model for prostate shape using principal component analysis and to study the local texture difference between prostate and nonprostate tissue close to the different prostate surface subregions. We used the learned shape and texture characteristics of the prostate in CT images and then combined them with user inputs to segment a new image. We trained our segmentation algorithm using 23 CT images and tested the algorithm on two sets of 10 nonbrachytherapy and 37 postlow dose rate brachytherapy CT images. We used a set of error metrics to evaluate the segmentation results using two experts' manual reference segmentations. For both nonbrachytherapy and post-brachytherapy image sets, the average measured Dice similarity coefficient (DSC) was 88% and the average mean absolute distance (MAD) was 1.9 mm. The average measured differences between the two experts on both datasets were 92% (DSC) and 1.1 mm (MAD). The proposed, semiautomatic segmentation algorithm showed a fast, robust, and accurate performance for 3D prostate segmentation of CT images, specifically when no previous, intrapatient information, that is, previously segmented images, was available. The accuracy of the algorithm is comparable to the best performance results reported in the literature and approaches the interexpert variability observed in manual segmentation. © 2018 American Association of Physicists in Medicine.

A non-rigid point matching method with local topology preservation for accurate bladder dose summation in high dose rate cervical brachytherapy.

PubMed

Chen, Haibin; Zhong, Zichun; Liao, Yuliang; Pompoš, Arnold; Hrycushko, Brian; Albuquerque, Kevin; Zhen, Xin; Zhou, Linghong; Gu, Xuejun

2016-02-07

GEC-ESTRO guidelines for high dose rate cervical brachytherapy advocate the reporting of the D2cc (the minimum dose received by the maximally exposed 2cc volume) to organs at risk. Due to large interfractional organ motion, reporting of accurate cumulative D2cc over a multifractional course is a non-trivial task requiring deformable image registration and deformable dose summation. To efficiently and accurately describe the point-to-point correspondence of the bladder wall over all treatment fractions while preserving local topologies, we propose a novel graphic processing unit (GPU)-based non-rigid point matching algorithm. This is achieved by introducing local anatomic information into the iterative update of correspondence matrix computation in the 'thin plate splines-robust point matching' (TPS-RPM) scheme. The performance of the GPU-based TPS-RPM with local topology preservation algorithm (TPS-RPM-LTP) was evaluated using four numerically simulated synthetic bladders having known deformations, a custom-made porcine bladder phantom embedded with twenty one fiducial markers, and 29 fractional computed tomography (CT) images from seven cervical cancer patients. Results show that TPS-RPM-LTP achieved excellent geometric accuracy with landmark residual distance error (RDE) of 0.7  ±  0.3 mm for the numerical synthetic data with different scales of bladder deformation and structure complexity, and 3.7  ±  1.8 mm and 1.6  ±  0.8 mm for the porcine bladder phantom with large and small deformation, respectively. The RDE accuracy of the urethral orifice landmarks in patient bladders was 3.7  ±  2.1 mm. When compared to the original TPS-RPM, the TPS-RPM-LTP improved landmark matching by reducing landmark RDE by 50  ±  19%, 37  ±  11% and 28  ±  11% for the synthetic, porcine phantom and the patient bladders, respectively. This was achieved with a computational time of less than 15 s in all cases with GPU acceleration. The efficiency and accuracy shown with the TPS-RPM-LTP indicate that it is a practical and promising tool for bladder dose summation in adaptive cervical cancer brachytherapy.

A non-rigid point matching method with local topology preservation for accurate bladder dose summation in high dose rate cervical brachytherapy

NASA Astrophysics Data System (ADS)

Chen, Haibin; Zhong, Zichun; Liao, Yuliang; Pompoš, Arnold; Hrycushko, Brian; Albuquerque, Kevin; Zhen, Xin; Zhou, Linghong; Gu, Xuejun

2016-02-01

GEC-ESTRO guidelines for high dose rate cervical brachytherapy advocate the reporting of the D2cc (the minimum dose received by the maximally exposed 2cc volume) to organs at risk. Due to large interfractional organ motion, reporting of accurate cumulative D2cc over a multifractional course is a non-trivial task requiring deformable image registration and deformable dose summation. To efficiently and accurately describe the point-to-point correspondence of the bladder wall over all treatment fractions while preserving local topologies, we propose a novel graphic processing unit (GPU)-based non-rigid point matching algorithm. This is achieved by introducing local anatomic information into the iterative update of correspondence matrix computation in the ‘thin plate splines-robust point matching’ (TPS-RPM) scheme. The performance of the GPU-based TPS-RPM with local topology preservation algorithm (TPS-RPM-LTP) was evaluated using four numerically simulated synthetic bladders having known deformations, a custom-made porcine bladder phantom embedded with twenty one fiducial markers, and 29 fractional computed tomography (CT) images from seven cervical cancer patients. Results show that TPS-RPM-LTP achieved excellent geometric accuracy with landmark residual distance error (RDE) of 0.7  ±  0.3 mm for the numerical synthetic data with different scales of bladder deformation and structure complexity, and 3.7  ±  1.8 mm and 1.6  ±  0.8 mm for the porcine bladder phantom with large and small deformation, respectively. The RDE accuracy of the urethral orifice landmarks in patient bladders was 3.7  ±  2.1 mm. When compared to the original TPS-RPM, the TPS-RPM-LTP improved landmark matching by reducing landmark RDE by 50  ±  19%, 37  ±  11% and 28  ±  11% for the synthetic, porcine phantom and the patient bladders, respectively. This was achieved with a computational time of less than 15 s in all cases with GPU acceleration. The efficiency and accuracy shown with the TPS-RPM-LTP indicate that it is a practical and promising tool for bladder dose summation in adaptive cervical cancer brachytherapy.

Rectourethral fistula following LDR brachytherapy.

PubMed

Borchers, Holger; Pinkawa, Michael; Donner, Andreas; Wolter, Timm P; Pallua, Norbert; Eble, Michael J; Jakse, Gerhard

2009-01-01

Modern LDR brachytherapy has drastically reduced rectal toxicity and decreased the occurrence of rectourethral fistulas to <0.5% of patients. Therefore, symptoms of late-onset sequelae are often ignored initially. These fistulas cause severe patient morbidity and require interdisciplinary treatment. We report on the occurrence and management of a rectourethral fistula which occurred 4 years after (125)I seed implantation. Copyright 2009 S. Karger AG, Basel.

MO-A-BRB-02: Considerations and Issues in Electronic Charting for Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richardson, S.

2015-06-15

The process of converting to an electronic chart for radiation therapy can be daunting. It requires a dedicated committee to first research and choose appropriate software, to review the entire documentation policy and flow of the clinic, to convert this system to electronic form or if necessary, redesign the system to more easily conform to the electronic process. Those making the conversion and those who already use electronic charting would benefit from the shared experience of those who have been through the process in the past. Therefore TG262 was convened to provide guidance on electronic charting for external beam radiationmore » therapy and brachytherapy. This course will present the results of an internal survey of task group members on EMR practices in External Beam Radiation Therapy as well as discuss important issues in EMR development and structure for both EBRT and brachytherapy. Learning Objectives: Be familiarized with common practices and pitfalls in development and maintenance of an electronic chart in Radiation Oncology Be familiarized with important issues related to electronic charting in External Beam Radiation Therapy Be familiarized with important issues related to electronic charting in Brachytherapy.« less

Optical fibre luminescence sensor for real-time LDR brachytherapy dosimetry

NASA Astrophysics Data System (ADS)

Woulfe, P.; Sullivan, F. J.; O'Keeffe, S.

2016-05-01

An optical fibre sensor for monitoring low dose radiation is presented. The sensor is based on a scintillation material embedded within the optical fibre core, which emits visible light when exposed to low level ionising radiation. The incident level of ionising radiation can be determined by analysing the optical emission. An optical fibre sensor is presented, based on radioluminescence whereby radiation sensitive scintillation material, terbium doped gadolinium oxysulphide (Gd2O2S:Tb), is embedded in a cavity of 250μm of a 500μm plastic optical fibre. The sensor is designed for in-vivo monitoring of the radiation dose during radio-active seed implantation for brachytherapy, in prostate cancer treatment, providing oncologists with real-time information of the radiation dose to the target area and/or nearby critical structures. The radiation from the brachytherapy seeds causes emission of visible light from the scintillation material through the process of radioluminescence, which penetrates the fibre, propagating along the optical fibre for remote detection using a multi-pixel photon counter. The sensor demonstrates a high sensitivity to Iodine-125, the radioactive source most commonly used in brachytherapy for treating prostate cancer.

Anode optimization for miniature electronic brachytherapy X-ray sources using Monte Carlo and computational fluid dynamic codes

PubMed Central

Khajeh, Masoud; Safigholi, Habib

2015-01-01

A miniature X-ray source has been optimized for electronic brachytherapy. The cooling fluid for this device is water. Unlike the radionuclide brachytherapy sources, this source is able to operate at variable voltages and currents to match the dose with the tumor depth. First, Monte Carlo (MC) optimization was performed on the tungsten target-buffer thickness layers versus energy such that the minimum X-ray attenuation occurred. Second optimization was done on the selection of the anode shape based on the Monte Carlo in water TG-43U1 anisotropy function. This optimization was carried out to get the dose anisotropy functions closer to unity at any angle from 0° to 170°. Three anode shapes including cylindrical, spherical, and conical were considered. Moreover, by Computational Fluid Dynamic (CFD) code the optimal target-buffer shape and different nozzle shapes for electronic brachytherapy were evaluated. The characterization criteria of the CFD were the minimum temperature on the anode shape, cooling water, and pressure loss from inlet to outlet. The optimal anode was conical in shape with a conical nozzle. Finally, the TG-43U1 parameters of the optimal source were compared with the literature. PMID:26966563

A new optimization method using a compressed sensing inspired solver for real-time LDR-brachytherapy treatment planning

NASA Astrophysics Data System (ADS)

Guthier, C.; Aschenbrenner, K. P.; Buergy, D.; Ehmann, M.; Wenz, F.; Hesser, J. W.

2015-03-01

This work discusses a novel strategy for inverse planning in low dose rate brachytherapy. It applies the idea of compressed sensing to the problem of inverse treatment planning and a new solver for this formulation is developed. An inverse planning algorithm was developed incorporating brachytherapy dose calculation methods as recommended by AAPM TG-43. For optimization of the functional a new variant of a matching pursuit type solver is presented. The results are compared with current state-of-the-art inverse treatment planning algorithms by means of real prostate cancer patient data. The novel strategy outperforms the best state-of-the-art methods in speed, while achieving comparable quality. It is able to find solutions with comparable values for the objective function and it achieves these results within a few microseconds, being up to 542 times faster than competing state-of-the-art strategies, allowing real-time treatment planning. The sparse solution of inverse brachytherapy planning achieved with methods from compressed sensing is a new paradigm for optimization in medical physics. Through the sparsity of required needles and seeds identified by this method, the cost of intervention may be reduced.

A new optimization method using a compressed sensing inspired solver for real-time LDR-brachytherapy treatment planning.

PubMed

Guthier, C; Aschenbrenner, K P; Buergy, D; Ehmann, M; Wenz, F; Hesser, J W

2015-03-21

This work discusses a novel strategy for inverse planning in low dose rate brachytherapy. It applies the idea of compressed sensing to the problem of inverse treatment planning and a new solver for this formulation is developed. An inverse planning algorithm was developed incorporating brachytherapy dose calculation methods as recommended by AAPM TG-43. For optimization of the functional a new variant of a matching pursuit type solver is presented. The results are compared with current state-of-the-art inverse treatment planning algorithms by means of real prostate cancer patient data. The novel strategy outperforms the best state-of-the-art methods in speed, while achieving comparable quality. It is able to find solutions with comparable values for the objective function and it achieves these results within a few microseconds, being up to 542 times faster than competing state-of-the-art strategies, allowing real-time treatment planning. The sparse solution of inverse brachytherapy planning achieved with methods from compressed sensing is a new paradigm for optimization in medical physics. Through the sparsity of required needles and seeds identified by this method, the cost of intervention may be reduced.

MAGIC with formaldehyde applied to dosimetry of HDR brachytherapy source

NASA Astrophysics Data System (ADS)

Marques; T; Fernandes; J; Barbi; G; Nicolucci; P; Baffa; O

2009-05-01

The use of polymer gel dosimeters in brachytherapy can allow the determination of three-dimensional dose distributions in large volumes and with high spatial resolution if an adequate calibration process is performed. One of the major issues in these experiments is the polymer gel response dependence on dose rate when high dose rate sources are used and the doses in the vicinity of the sources are to be determinated. In this study, the response of a modified MAGIC polymer gel with formaldehyde around an Iridium-192 HDR brachytherapy source is presented. Experimental results obtained with this polymer gel were compared with ionization chamber measurements and with Monte Carlo simulation with PENELOPE. A maximum difference of 3.10% was found between gel dose measurements and Monte Carlo simulation at a radial distance of 18 mm from the source. The results obtained show that the gel's response is strongly influenced by dose rate and that a different calibration should be used for the vicinity of the source and for regions of lower dose rates. The results obtained in this study show that, provided the proper calibration is performed, MAGIC with formaldehyde can be successfully used to accurate determinate dose distributions form high dose rate brachytherapy sources.

Optical fibre luminescence sensor for real-time LDR brachytherapy dosimetry

NASA Astrophysics Data System (ADS)

Woulfe, P.; O'Keeffe, S.; Sullivan, F. J.

2018-02-01

An optical fibre sensor for monitoring low dose radiation is presented. The sensor is based on a scintillation material embedded within the optical fibre core, which emits visible light when exposed to low level ionising radiation. The incident level of ionising radiation can be determined by analysing the optical emission. An optical fibre sensor is developed, based on radioluminescence whereby radiation sensitive scintillation material, terbium doped gadolinium oxysulphide (Gd2O2S:Tb), is embedded in a cavity of 700μm of a 1mm plastic optical fibre. The sensor is designed for in-vivo monitoring of the radiation dose during radio-active seed implantation for low dose rate (LDR) brachytherapy, in prostate cancer treatment, providing radiation oncologists with real-time information of the radiation dose to the target area and/or nearby organs at risk (OARs). The radiation from the brachytherapy seeds causes emission of visible light from the scintillation material through the process of radioluminescence, which penetrates the fibre, propagating along the optical fibre for remote detection using a multi-pixel photon counter. The sensor demonstrates a high sensitivity to 0.397mCi of Iodine125, the radioactive source most commonly used in brachytherapy for treating prostate cancer.

Human Error Assessment and Reduction Technique (HEART) and Human Factor Analysis and Classification System (HFACS)

NASA Technical Reports Server (NTRS)

Alexander, Tiffaney Miller

2017-01-01

Research results have shown that more than half of aviation, aerospace and aeronautics mishaps incidents are attributed to human error. As a part of Safety within space exploration ground processing operations, the identification and/or classification of underlying contributors and causes of human error must be identified, in order to manage human error. This research provides a framework and methodology using the Human Error Assessment and Reduction Technique (HEART) and Human Factor Analysis and Classification System (HFACS), as an analysis tool to identify contributing factors, their impact on human error events, and predict the Human Error probabilities (HEPs) of future occurrences. This research methodology was applied (retrospectively) to six (6) NASA ground processing operations scenarios and thirty (30) years of Launch Vehicle related mishap data. This modifiable framework can be used and followed by other space and similar complex operations.

Human Error Assessment and Reduction Technique (HEART) and Human Factor Analysis and Classification System (HFACS)

NASA Technical Reports Server (NTRS)

Alexander, Tiffaney Miller

2017-01-01

Research results have shown that more than half of aviation, aerospace and aeronautics mishaps/incidents are attributed to human error. As a part of Safety within space exploration ground processing operations, the identification and/or classification of underlying contributors and causes of human error must be identified, in order to manage human error. This research provides a framework and methodology using the Human Error Assessment and Reduction Technique (HEART) and Human Factor Analysis and Classification System (HFACS), as an analysis tool to identify contributing factors, their impact on human error events, and predict the Human Error probabilities (HEPs) of future occurrences. This research methodology was applied (retrospectively) to six (6) NASA ground processing operations scenarios and thirty (30) years of Launch Vehicle related mishap data. This modifiable framework can be used and followed by other space and similar complex operations.

Human Error Assessment and Reduction Technique (HEART) and Human Factor Analysis and Classification System (HFACS)

NASA Technical Reports Server (NTRS)

Alexander, Tiffaney Miller

2017-01-01

Research results have shown that more than half of aviation, aerospace and aeronautics mishaps incidents are attributed to human error. As a part of Quality within space exploration ground processing operations, the identification and or classification of underlying contributors and causes of human error must be identified, in order to manage human error.This presentation will provide a framework and methodology using the Human Error Assessment and Reduction Technique (HEART) and Human Factor Analysis and Classification System (HFACS), as an analysis tool to identify contributing factors, their impact on human error events, and predict the Human Error probabilities (HEPs) of future occurrences. This research methodology was applied (retrospectively) to six (6) NASA ground processing operations scenarios and thirty (30) years of Launch Vehicle related mishap data. This modifiable framework can be used and followed by other space and similar complex operations.

Comment on ‘egs_brachy: a versatile and fast Monte Carlo code for brachytherapy’

NASA Astrophysics Data System (ADS)

Yegin, Gultekin

2018-02-01

In a recent paper (Chamberland et al 2016 Phys. Med. Biol. 61 8214) develop a new Monte Carlo code called egs_brachy for brachytherapy treatments. It is based on EGSnrc, and written in the C++ programming language. In order to benchmark the egs_brachy code, the authors use it in various test case scenarios in which complex geometry conditions exist. Another EGSnrc based brachytherapy dose calculation engine, BrachyDose, is used for dose comparisons. The authors fail to prove that egs_brachy can produce reasonable dose values for brachytherapy sources in a given medium. The dose comparisons in the paper are erroneous and misleading. egs_brachy should not be used in any further research studies unless and until all the potential bugs are fixed in the code.

Understanding human management of automation errors

PubMed Central

McBride, Sara E.; Rogers, Wendy A.; Fisk, Arthur D.

2013-01-01

Automation has the potential to aid humans with a diverse set of tasks and support overall system performance. Automated systems are not always reliable, and when automation errs, humans must engage in error management, which is the process of detecting, understanding, and correcting errors. However, this process of error management in the context of human-automation interaction is not well understood. Therefore, we conducted a systematic review of the variables that contribute to error management. We examined relevant research in human-automation interaction and human error to identify critical automation, person, task, and emergent variables. We propose a framework for management of automation errors to incorporate and build upon previous models. Further, our analysis highlights variables that may be addressed through design and training to positively influence error management. Additional efforts to understand the error management process will contribute to automation designed and implemented to support safe and effective system performance. PMID:25383042

Understanding human management of automation errors.

PubMed

McBride, Sara E; Rogers, Wendy A; Fisk, Arthur D

2014-01-01

Automation has the potential to aid humans with a diverse set of tasks and support overall system performance. Automated systems are not always reliable, and when automation errs, humans must engage in error management, which is the process of detecting, understanding, and correcting errors. However, this process of error management in the context of human-automation interaction is not well understood. Therefore, we conducted a systematic review of the variables that contribute to error management. We examined relevant research in human-automation interaction and human error to identify critical automation, person, task, and emergent variables. We propose a framework for management of automation errors to incorporate and build upon previous models. Further, our analysis highlights variables that may be addressed through design and training to positively influence error management. Additional efforts to understand the error management process will contribute to automation designed and implemented to support safe and effective system performance.

Human operator response to error-likely situations in complex engineering systems

NASA Technical Reports Server (NTRS)

Morris, Nancy M.; Rouse, William B.

1988-01-01

The causes of human error in complex systems are examined. First, a conceptual framework is provided in which two broad categories of error are discussed: errors of action, or slips, and errors of intention, or mistakes. Conditions in which slips and mistakes might be expected to occur are identified, based on existing theories of human error. Regarding the role of workload, it is hypothesized that workload may act as a catalyst for error. Two experiments are presented in which humans' response to error-likely situations were examined. Subjects controlled PLANT under a variety of conditions and periodically provided subjective ratings of mental effort. A complex pattern of results was obtained, which was not consistent with predictions. Generally, the results of this research indicate that: (1) humans respond to conditions in which errors might be expected by attempting to reduce the possibility of error, and (2) adaptation to conditions is a potent influence on human behavior in discretionary situations. Subjects' explanations for changes in effort ratings are also explored.

PSA Nadir of <0.5 ng/mL Following Brachytherapy for Early-Stage Prostate Adenocarcinoma is Associated With Freedom From Prostate-Specific Antigen Failure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ko, Eric C.; Stone, Nelson N.; Department of Urology, Mount Sinai Medical Center, New York, NY

2012-06-01

Purpose: Because limited information exists regarding whether the rate or magnitude of PSA decline following brachytherapy predicts long-term clinical outcomes, we evaluated whether achieving a prostate-specific antigen (PSA) nadir (nPSA) <0.5 ng/mL following brachytherapy is associated with decreased PSA failure and/or distant metastasis. Methods and Materials: We retrospectively analyzed our database of early-stage prostate adenocarcinoma patients who underwent brachytherapy, excluding those receiving androgen-deprivation therapy and those with <2 years follow-up. Median and mean pretreatment PSA were 6 ng/mL and 7.16 ng/mL, respectively. By clinical stage, 775 were low risk ({<=}T2a), 126 were intermediate risk (T2b), and 20 were high riskmore » (>T2b). By Gleason score, 840 were low risk ({<=}6), 71 were intermediate risk (7), and 10 were high risk (>7). Patients were treated with brachytherapy only (I-125, n = 779, or Pd-103, n = 47), or brachytherapy + external-beam radiation therapy (n = 95). Median follow-up was 6.3 years. We noted whether nPSA <0.5 ng/mL was achieved and the time to achieve this nadir and tested for associations with pretreatment risk factors. We also determined whether this PSA endpoint was associated with decreased PSA failure or distant metastasis. Results: Absence of high-risk factors in clinical stage ({<=}T2b), Gleason score ({<=}7), and pretreatment PSA ({<=}20 ng/mL) was significantly associated with achieving nPSA <0.5 ng/mL. By Kaplan-Meier analysis, patients achieving nPSA <0.5 ng/mL had significantly higher long-term freedom from biochemical failure (FFBF) than nonresponders (5-year FFBF: 95.2 {+-} 0.8% vs. 71.5 {+-} 6.7%; p < 0.0005). Among responders, those who achieved nPSA <0.5 ng/mL in {<=}5 years had higher FFBF than those requiring >5 years (5-year FFBF: 96.7 {+-} 0.7% vs. 80.8 {+-} 4.6%; p < 0.0005). On multivariate analysis, patients who achieved nPSA <0.5 ng/mL in {<=}5 years had significantly higher FFBF than other patients. Conclusions: Pretreatment risk factors (clinical tumor stage, Gleason score, pretreatment PSA) strongly predict for patients achieving nPSA <0.5 ng/mL following brachytherapy, and this cohort had significantly higher long-term FFBF.« less

PSA nadir of <0.5 ng/mL following brachytherapy for early-stage prostate adenocarcinoma is associated with freedom from prostate-specific antigen failure.

PubMed

Ko, Eric C; Stone, Nelson N; Stock, Richard G

2012-06-01

Because limited information exists regarding whether the rate or magnitude of PSA decline following brachytherapy predicts long-term clinical outcomes, we evaluated whether achieving a prostate-specific antigen (PSA) nadir (nPSA) <0.5 ng/mL following brachytherapy is associated with decreased PSA failure and/or distant metastasis. We retrospectively analyzed our database of early-stage prostate adenocarcinoma patients who underwent brachytherapy, excluding those receiving androgen-deprivation therapy and those with <2 years follow-up. Median and mean pretreatment PSA were 6 ng/mL and 7.16 ng/mL, respectively. By clinical stage, 775 were low risk (≤ T2a), 126 were intermediate risk (T2b), and 20 were high risk (>T2b). By Gleason score, 840 were low risk (≤ 6), 71 were intermediate risk (7), and 10 were high risk (>7). Patients were treated with brachytherapy only (I-125, n = 779, or Pd-103, n = 47), or brachytherapy + external-beam radiation therapy (n = 95). Median follow-up was 6.3 years. We noted whether nPSA <0.5 ng/mL was achieved and the time to achieve this nadir and tested for associations with pretreatment risk factors. We also determined whether this PSA endpoint was associated with decreased PSA failure or distant metastasis. Absence of high-risk factors in clinical stage (≤ T2b), Gleason score (≤ 7), and pretreatment PSA (≤ 20 ng/mL) was significantly associated with achieving nPSA <0.5 ng/mL. By Kaplan-Meier analysis, patients achieving nPSA <0.5 ng/mL had significantly higher long-term freedom from biochemical failure (FFBF) than nonresponders (5-year FFBF: 95.2 ± 0.8% vs. 71.5 ± 6.7%; p < 0.0005). Among responders, those who achieved nPSA <0.5 ng/mL in ≤ 5 years had higher FFBF than those requiring >5 years (5-year FFBF: 96.7 ± 0.7% vs. 80.8 ± 4.6%; p < 0.0005). On multivariate analysis, patients who achieved nPSA <0.5 ng/mL in ≤ 5 years had significantly higher FFBF than other patients. Pretreatment risk factors (clinical tumor stage, Gleason score, pretreatment PSA) strongly predict for patients achieving nPSA <0.5 ng/mL following brachytherapy, and this cohort had significantly higher long-term FFBF. Copyright © 2012 Elsevier Inc. All rights reserved.

Real-Time Verification of a High-Dose-Rate Iridium 192 Source Position Using a Modified C-Arm Fluoroscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nose, Takayuki, E-mail: nose-takayuki@nms.ac.jp; Chatani, Masashi; Otani, Yuki

Purpose: High-dose-rate (HDR) brachytherapy misdeliveries can occur at any institution, and they can cause disastrous results. Even a patient's death has been reported. Misdeliveries could be avoided with real-time verification methods. In 1996, we developed a modified C-arm fluoroscopic verification of an HDR Iridium 192 source position prevent these misdeliveries. This method provided excellent image quality sufficient to detect errors, and it has been in clinical use at our institutions for 20 years. The purpose of the current study is to introduce the mechanisms and validity of our straightforward C-arm fluoroscopic verification method. Methods and Materials: Conventional X-ray fluoroscopic images aremore » degraded by spurious signals and quantum noise from Iridium 192 photons, which make source verification impractical. To improve image quality, we quadrupled the C-arm fluoroscopic X-ray dose per pulse. The pulse rate was reduced by a factor of 4 to keep the average exposure compliant with Japanese medical regulations. The images were then displayed with quarter-frame rates. Results: Sufficient quality was obtained to enable observation of the source position relative to both the applicators and the anatomy. With this method, 2 errors were detected among 2031 treatment sessions for 370 patients within a 6-year period. Conclusions: With the use of a modified C-arm fluoroscopic verification method, treatment errors that were otherwise overlooked were detected in real time. This method should be given consideration for widespread use.« less

Real-Time Verification of a High-Dose-Rate Iridium 192 Source Position Using a Modified C-Arm Fluoroscope.

PubMed

Nose, Takayuki; Chatani, Masashi; Otani, Yuki; Teshima, Teruki; Kumita, Shinichirou

2017-03-15

High-dose-rate (HDR) brachytherapy misdeliveries can occur at any institution, and they can cause disastrous results. Even a patient's death has been reported. Misdeliveries could be avoided with real-time verification methods. In 1996, we developed a modified C-arm fluoroscopic verification of an HDR Iridium 192 source position prevent these misdeliveries. This method provided excellent image quality sufficient to detect errors, and it has been in clinical use at our institutions for 20 years. The purpose of the current study is to introduce the mechanisms and validity of our straightforward C-arm fluoroscopic verification method. Conventional X-ray fluoroscopic images are degraded by spurious signals and quantum noise from Iridium 192 photons, which make source verification impractical. To improve image quality, we quadrupled the C-arm fluoroscopic X-ray dose per pulse. The pulse rate was reduced by a factor of 4 to keep the average exposure compliant with Japanese medical regulations. The images were then displayed with quarter-frame rates. Sufficient quality was obtained to enable observation of the source position relative to both the applicators and the anatomy. With this method, 2 errors were detected among 2031 treatment sessions for 370 patients within a 6-year period. With the use of a modified C-arm fluoroscopic verification method, treatment errors that were otherwise overlooked were detected in real time. This method should be given consideration for widespread use. Copyright © 2016 Elsevier Inc. All rights reserved.

Human error and human factors engineering in health care.

PubMed

Welch, D L

1997-01-01

Human error is inevitable. It happens in health care systems as it does in all other complex systems, and no measure of attention, training, dedication, or punishment is going to stop it. The discipline of human factors engineering (HFE) has been dealing with the causes and effects of human error since the 1940's. Originally applied to the design of increasingly complex military aircraft cockpits, HFE has since been effectively applied to the problem of human error in such diverse systems as nuclear power plants, NASA spacecraft, the process control industry, and computer software. Today the health care industry is becoming aware of the costs of human error and is turning to HFE for answers. Just as early experimental psychologists went beyond the label of "pilot error" to explain how the design of cockpits led to air crashes, today's HFE specialists are assisting the health care industry in identifying the causes of significant human errors in medicine and developing ways to eliminate or ameliorate them. This series of articles will explore the nature of human error and how HFE can be applied to reduce the likelihood of errors and mitigate their effects.

``In Vivo'' Dosimetry in High Dose Rate Brachytherapy for Cervical Cancer Treatments

NASA Astrophysics Data System (ADS)

González-Azcorra, S. A.; Mota-García, A.; Poitevín-Chacón, M. A.; Santamaría-Torruco, B. J.; Rodríguez-Ponce, M.; Herrera-Martínez, F. P.; Gamboa de Buen, I.; Ruíz-Trejo, C.; Buenfil, A. E.

2008-08-01

In this prospective study, rectal dose was measured "in vivo" using TLD-100 crystals (3×3×1 mm3), and it has been compared to the prescribed dose. Measurements were performed in patients with cervical cancer classified in FIGO stages IB-IIIB and treated with high dose rate brachytherapy (HDR BT) at the Instituto Nacional de Cancerología (INCan).

10 CFR 35.2067 - Records of leaks tests and inventory of sealed sources and brachytherapy sources.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Records of leaks tests and inventory of sealed sources and... MATERIAL Records § 35.2067 Records of leaks tests and inventory of sealed sources and brachytherapy sources. (a) A licensee shall retain records of leak tests required by § 35.67(b) for 3 years. The records...

Applications of integrated human error identification techniques on the chemical cylinder change task.

PubMed

Cheng, Ching-Min; Hwang, Sheue-Ling

2015-03-01

This paper outlines the human error identification (HEI) techniques that currently exist to assess latent human errors. Many formal error identification techniques have existed for years, but few have been validated to cover latent human error analysis in different domains. This study considers many possible error modes and influential factors, including external error modes, internal error modes, psychological error mechanisms, and performance shaping factors, and integrates several execution procedures and frameworks of HEI techniques. The case study in this research was the operational process of changing chemical cylinders in a factory. In addition, the integrated HEI method was used to assess the operational processes and the system's reliability. It was concluded that the integrated method is a valuable aid to develop much safer operational processes and can be used to predict human error rates on critical tasks in the plant. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Prognostic implication of simultaneous anemia and lymphopenia during concurrent chemoradiotherapy in cervical squamous cell carcinoma.

PubMed

Cho, Oyeon; Chun, Mison; Oh, Young-Taek; Noh, O Kyu; Chang, Suk-Joon; Ryu, Hee-Sug; Lee, Eun Ju

2017-10-01

Radioresistance often leads to poor survival in concurrent chemoradiotherapy-treated cervical squamous cell carcinoma, and reliable biomarkers can improve prognosis. We compared the prognostic potential of hemoglobin, absolute neutrophil count, and absolute lymphocyte count with that of squamous cell carcinoma antigen in concurrent chemoradiotherapy-treated squamous cell carcinoma. We analyzed 152 patients with concurrent chemoradiotherapy and high-dose-rate intracavitary brachytherapy-treated cervical squamous cell carcinoma. Hemoglobin, absolute neutrophil count, absolute lymphocyte count, and squamous cell carcinoma antigen were quantitated and correlated with survival, using Cox regression, receiver operating characteristic curve analysis, and Kaplan-Meier plots. Both hemoglobin and absolute lymphocyte count in the second week of concurrent chemoradiotherapy (Hb2 and ALC2) and squamous cell carcinoma antigen in the third week of concurrent chemoradiotherapy (mid-squamous cell carcinoma antigen) correlated significantly with disease-specific survival and progression-free survival. The ratio of high-dose-rate intracavitary brachytherapy dose to total dose (high-dose-rate intracavitary brachytherapy ratio) correlated significantly with progression-free survival. Patients with both low Hb2 (≤11 g/dL) and ALC2 (≤639 cells/µL) showed a lower 5-year disease-specific survival rate than those with high Hb2 and/or ALC2, regardless of mid-squamous cell carcinoma antigen (mid-squamous cell carcinoma antigen: ≤4.7 ng/mL; 5-year disease-specific survival rate: 85.5% vs 94.6%, p = 0.0096, and mid-squamous cell carcinoma antigen: >4.7 ng/mL; 5-year disease-specific survival rate: 43.8% vs 66.7%, p = 0.192). When both Hb2 and ALC2 were low, the low high-dose-rate intracavitary brachytherapy ratio (≤0.43) subgroup displayed significantly lower 5-year disease-specific survival rate compared to the subgroup high high-dose-rate intracavitary brachytherapy ratio (>0.43) (62.5% vs 88.2%, p = 0.0067). Patients with both anemia and lymphopenia during concurrent chemoradiotherapy showed poor survival, independent of mid-squamous cell carcinoma antigen, and escalating high-dose-rate intracavitary brachytherapy ratio might improve survival.

Developing A Directional High-Dose Rate (d-HDR) Brachytherapy Source

NASA Astrophysics Data System (ADS)

Heredia, Athena Yvonne

Conventional sources used in brachytherapy provide nearly isotropic or radially symmetric dose distributions. Optimizations of dose distributions have been limited to varied dwell times at specified locations within a given treatment volume, or manipulations in source position for seed implantation techniques. In years past, intensity modulated brachytherapy (IMBT) has been used to reduce the amount of radiation to surrounding sensitive structures in select intracavitary cases by adding space or partial shields. Previous work done by Lin et al., at the University of Wisconsin-Madison, has shown potential improvements in conformality for brachytherapy treatments using a directionally shielded low dose rate (LDR) source for treatments in breast and prostate. Directional brachytherapy sources irradiate approximately half of the radial angles around the source, and adequately shield a quarter of the radial angles on the opposite side, with sharp gradient zones between the treated half and shielded quarter. With internally shielded sources, the radiation can be preferentially emitted in such a way as to reduce toxicities in surrounding critical organs. The objective of this work is to present findings obtained in the development of a new directional high dose rate (d-HDR) source. To this goal, 103Pd (Z = 46) is reintroduced as a potential radionuclide for use in HDR brachytherapy. 103Pd has a low average photon energy (21 keV) and relatively short half -life (17 days), which is why it has historically been used in low dose rate applications and implantation techniques. Pd-103 has a carrier-free specific activity of 75000 Ci/g. Using cyclotron produced 103Pd, near carrier-free specific activities can be achieved, providing suitability for high dose rate applications. The evolution of the d-HDR source using Monte Carlo simulations is presented, along with dosimetric parameters used to fully characterize the source. In addition, a discussion on how to obtain elemental palladium, Pd(0), will be discussed in detail. Directional HDR has the potential to improve upon current treatments, providing better dose conformality to the target volume, while maintaining the benefits of HDR applications.

An electronic brachytherapy technique for treating squamous cell carcinoma in situ of the digit: a case report.

PubMed

Arterbery, V Elayne; Watson, Alice C

2013-04-15

Squamous cell carcinoma in situ of the digit presents a complex management problem, which is usually treated with surgery or radiation or topical agents. The outcome of the surgical treatment can be an undesirable cosmetic result and loss of function. We report a unique Electronic Brachytherapy technique to treat the digit, which uses a 50 Kv miniaturized X-ray source with specialized applicators. A 62-year-old African-American male was presented with a 12-month history of gradual darkening of the dorsal-distal middle left finger. Examination revealed a hyper pigmented scaly patch on the proximal to lateral nail fold of the L 3rd finger, nail dystrophy, and vertical split in the lateral section of the nail. The patient underwent evaluation of the lesion by Plastic Surgery with the removal of the lateral nail and a nail bed biopsy. Pathology revealed squamous cell carcinoma in situ with a possible focal positive, deep margin. The patient deliberated over surgical opinions, and eventually decided on radiation. A high dose rate Electronic Brachytherapy system using the XOFT Accent controller delivered dose of 4000 cGy in eight fractions, twice weekly, with at least 48 hours between fractions and treatment prescribed to a depth of 0 to 2 mm. The Xoft unit has specialized skin applicators that permit superficial treatment. Parameters assessed included the efficacy, cosmetic results feasibility, and acute safety of the Electronic Brachytherapy technique. The patient exhibited moderate redness, hyperpigmentation erythema, desquamation, and Grade 1 to 2 edema acutely (following radiation), which resolved within 1 month of the treatment. Electronic brachytherapy treatment delivery took about 6 minutes, and the total procedure time was about 15 minutes. At the median follow-up of one year, the area revealed excellent cosmesis, and there was no infection or fat necrosis, desquamation, no cancer recurrence, and no evidence of fibrosis at the last follow-up. This suggests that Electronic Brachytherapy was a viable treatment option for this particular patient.

The Patient Burden of Bladder Outlet Obstruction after Prostate Cancer Treatment.

PubMed

Liberman, Daniel; Jarosek, Stephanie; Virnig, Beth A; Chu, Haitao; Elliott, Sean P

2016-05-01

Bladder outlet obstruction after prostate cancer therapy imposes a significant burden on health and quality of life in men. Our objective was to describe the burden of bladder outlet obstruction after prostate cancer therapy by detailing the type of procedures performed and how often those procedures were repeated in men with recurrent bladder outlet obstruction. Using SEER (Surveillance, Epidemiology and End Results)-Medicare linked data from 1992 to 2007 with followup through 2009 we identified 12,676 men who underwent at least 1 bladder outlet obstruction procedure after prostate cancer therapy, including external beam radiotherapy in 3,994, brachytherapy in 1,485, brachytherapy plus external beam radiotherapy in 1,847, radical prostatectomy in 4,736, radical prostatectomy plus external beam radiotherapy in 369 and cryotherapy in 245. Histogram, incidence rates and Cox proportional hazards models with repeat events analysis were done to describe the burden of repeat bladder outlet obstruction treatments stratified by prostate cancer therapy type. We describe the type of bladder outlet obstruction surgery grouped by level of invasiveness. At a median followup of 8.8 years 44.6% of men underwent 2 or more bladder outlet obstruction procedures. Compared to men who underwent radical prostatectomy those treated with brachytherapy and brachytherapy plus external beam radiotherapy were at increased adjusted risk for repeat bladder outlet obstruction treatment (HR 1.2 and 1.32, respectively, each p <0.05). After stricture incision the men treated with radical prostatectomy or radical prostatectomy plus external beam radiotherapy were most likely to undergo dilation at a rate of 34.7% to 35.0%. Stricture resection/ablation was more common after brachytherapy, external beam radiotherapy or brachytherapy plus external beam radiotherapy at a rate of 28.9% to 41.2%. Almost half of the men with bladder outlet obstruction after prostate cancer therapy undergo more than 1 procedure. Furthermore men with bladder outlet obstruction after radiotherapy undergo more invasive endoscopic therapies and are at higher risk for multiple treatments than men with bladder outlet obstruction after radical prostatectomy. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

SU-E-J-215: Towards MR-Only Image Guided Identification of Calcifications and Brachytherapy Seeds: Application to Prostate and Breast LDR Implant Dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elzibak, A; Fatemi-Ardekani, A; Soliman, A

Purpose: To identify and analyze the appearance of calcifications and brachytherapy seeds on magnitude and phase MRI images and to investigate whether they can be distinguished from each other on corrected phase images for application to prostate and breast low dose rate (LDR) implant dosimetry. Methods: An agar-based gel phantom containing two LDR brachytherapy seeds (Advantage Pd-103, IsoAid, 0.8mm diameter, 4.5mm length) and two spherical calcifications (large: 7mm diameter and small: 4mm diameter) was constructed and imaged on a 3T Philips MR scanner using a 16-channel head coil and a susceptibility weighted imaging (SWI) sequence (2mm slices, 320mm FOV, TR/more » TE= 26.5/5.3ms, 15 degree flip angle). The phase images were unwrapped and corrected using a 32×32, 2D Hanning high pass filter to remove background phase noise. Appearance of the seeds and calcifications was assessed visually and quantitatively using Osirix (http://www.osirix-viewer.com/). Results: As expected, calcifications and brachytherapy seeds appeared dark (hypointense) relative to the surrounding gel on the magnitude MRI images. The diameter of each seed without the surrounding artifact was measured to be 0.1 cm on the magnitude image, while diameters of 0.79 and 0.37 cm were measured for the larger and smaller calcifications, respectively. On the corrected phase images, the brachytherapy seeds and the calcifications appeared bright (hyperintense). The diameter of the seeds was larger on the phase images (0.17 cm) likely due to the dipole effect. Conclusion: MRI has the best soft tissue contrast for accurate organ delineation leading to most accurate implant dosimetry. This work demonstrated that phase images can potentially be useful in identifying brachytherapy seeds and calcifications in the prostate and breast due to their bright appearance, which helps in their visualization and quantification for accurate dosimetry using MR-only. Future work includes optimizing phase filters to best identify and delineate seeds and calcifications.« less

SU-F-T-61: Treatment Planning Observations for the CivaSheet Directional Brachytherapy Device Using VariSeed 9.0

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rivard, MJ; Rothley, DJ

2016-06-15

Purpose: The VariSeed 9.0 brachytherapy TPS is recently available and has new features such as ability to rotate a brachytherapy source away from normal to the imaging plane. Consequently, a dosimetric analysis was performed for a directional brachytherapy source (CivaSheet) with tests of this functionality and experiences from clinical treatment planning were documented. These observations contribute to safe, practical, and accurate use of such new software features. Methods: Several tests were established to evaluate the new rotational feature, specific to the CivaSheet for the first patients treated using this new brachytherapy device. These included suitability of imaging slice-thickness and in-planemore » resolution, window/level adjustments for brachytherapy source visualization, commissioning the source physical length for performing rotations, and using different planar and 3D window views to identify source orientation. Additional CivaSheet-specific tests were performed to determine the dosimetric influence on target coverage: changing the source tilt angle, source positioning in the treatment plan based on the CivaSheet rectangular array of CivaDots, and influence of prescription depth on the necessary treatment margin for adequate target coverage. Results: Higher imaging-resolution produced better accuracy for source orientation and positioning, with sub-millimeter CT slice-thickness and in-plane resolution preferred. Source rotation was possible only in sagittal or coronal views. The process for validating source orientation required iteratively altering rotations then checking them in the 3D view, which was cumbersome given the absence of quantitative plan documentation to indicate orientation. Given the small Pd-103 source size, influence of source tilt within 30° was negligible for <1.0 cm. Influence of source position was important when the source was positioned in/out of the adjacent source plane, causing changes of 15%, 7%, and 3% at depths of 0.5, 0.7, and 1.0 cm. Conclusion: The new TPS rotational feature worked well, but several issues were identified to improve the treatment planning process. Research supported in part by CivaTech Oncology, Inc. for Dr. Rivard.« less

Dosimetric intercomparison of permanent Ho-166 seed's implants and HDR Ir-192 brachytherapy in breast cancer.

PubMed

de Campos, Tarcisio Passos Ribeiro; Nogueira, Luciana Batista; Trindade, Bruno; Cuperschmid, Ethel Mizrahy

2016-01-01

To provide a comparative dosimetric analysis of permanent implants of Ho(166)-seeds and temporary HDR Ir(192)-brachytherapy through computational simulation. Brachytherapy with Ir(192)-HDR or LDR based on temporary wires or permanent radioactive seed implants can be used as dose reinforcement for breast radiation therapy. Permanent breast implants have not been a practical clinical routine; although, I(125) and Pd(103)-seeds have already been reported. Biodegradable Ho(166)-ceramic-seeds have been addressed recently. Simulations of implants of nine Ho(166)-seeds and equivalent with HDR Ir(192)-brachytherapy were elaborated in MCNP5, shaped in a computational multivoxel simulator which reproduced a female thorax phantom. Spatial dose rate distributions and dose-volume histograms were generated. Protocol's analysis involving exposure time, seed's activities and dose were performed. Permanent Ho(166)-seed implants presented a maximum dose rate per unit of contained activity (MDR) of 1.1601 μGy h(-1) Bq(-1); and, a normalized MDR in standard points (8 mm, equidistant to 03-seeds - SP1, 10 mm - SP2) of 1.0% (SP1) and 0.5% (SP2), respectively. Ir(192)-brachytherapy presented MDR of 4.3945 × 10(-3) μGy h(-1) Bq(-1); and, 30% (SP1), and 20% (SP2). Therefore, seed's implant activities of 333 MBq (Ho(166)) and 259 GBq (Ir(192)) produced prescribed doses of 58 Gy (SP1; 5d) and 56 Gy (SP1, 5 fractions, 6 min), respectively. Breast Ho(166)-implants of 37-111 MBq are attractive due to the high dose rate near 6-10 mm from seeds, equivalent to Ir(192)-brachytherapy of 259 GBq (3 fractions, 6 min) providing similar dose in standard points at a week; however, with spatial dose distribution better confined. The seed positioning can be adjusted for controlling the breast tumor, in stages I and II, in flat and deep tumors, without any breast volumetric limitation.

Dosimetric comparison between intra-cavitary breast brachytherapy techniques for accelerated partial breast irradiation and a novel stereotactic radiotherapy device for breast cancer: GammaPod™

NASA Astrophysics Data System (ADS)

Ödén, Jakob; Toma-Dasu, Iuliana; Yu, Cedric X.; Feigenberg, Steven J.; Regine, William F.; Mutaf, Yildirim D.

2013-07-01

The GammaPod™ device, manufactured by Xcision Medical Systems, is a novel stereotactic breast irradiation device. It consists of a hemispherical source carrier containing 36 Cobalt-60 sources, a tungsten collimator with two built-in collimation sizes, a dynamically controlled patient support table and a breast immobilization cup also functioning as the stereotactic frame for the patient. The dosimetric output of the GammaPod™ was modelled using a Monte Carlo based treatment planning system. For the comparison, three-dimensional (3D) models of commonly used intra-cavitary breast brachytherapy techniques utilizing single lumen and multi-lumen balloon as well as peripheral catheter multi-lumen implant devices were created and corresponding 3D dose calculations were performed using the American Association of Physicists in Medicine Task Group-43 formalism. Dose distributions for clinically relevant target volumes were optimized using dosimetric goals set forth in the National Surgical Adjuvant Breast and Bowel Project Protocol B-39. For clinical scenarios assuming similar target sizes and proximity to critical organs, dose coverage, dose fall-off profiles beyond the target and skin doses at given distances beyond the target were calculated for GammaPod™ and compared with the doses achievable by the brachytherapy techniques. The dosimetric goals within the protocol guidelines were fulfilled for all target sizes and irradiation techniques. For central targets, at small distances from the target edge (up to approximately 1 cm) the brachytherapy techniques generally have a steeper dose fall-off gradient compared to GammaPod™ and at longer distances (more than about 1 cm) the relation is generally observed to be opposite. For targets close to the skin, the relative skin doses were considerably lower for GammaPod™ than for any of the brachytherapy techniques. In conclusion, GammaPod™ allows adequate and more uniform dose coverage to centrally and peripherally located targets with an acceptable dose fall-off and lower relative skin dose than the brachytherapy techniques considered in this study.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jabbari, Siavash; Weinberg, Vivian K.; Kaprealian, Tania

Purpose: High dose rate (HDR) brachytherapy has been established as an excellent monotherapy or after external-beam radiotherapy (EBRT) boost treatment for prostate cancer (PCa). Recently, dosimetric studies have demonstrated the potential for achieving similar dosimetry with stereotactic body radiotherapy (SBRT) compared with HDR brachytherapy. Here, we report our technique, PSA nadir, and acute and late toxicity with SBRT as monotherapy and post-EBRT boost for PCa using HDR brachytherapy fractionation. Patients and Methods: To date, 38 patients have been treated with SBRT at University of California-San Francisco with a minimum follow-up of 12 months. Twenty of 38 patients were treated withmore » SBRT monotherapy (9.5 Gy Multiplication-Sign 4 fractions), and 18 were treated with SBRT boost (9.5 Gy Multiplication-Sign 2 fractions) post-EBRT and androgen deprivation therapy. PSA nadir to date for 44 HDR brachytherapy boost patients with disease characteristics similar to the SBRT boost cohort was also analyzed as a descriptive comparison. Results: SBRT was well tolerated. With a median follow-up of 18.3 months (range, 12.6-43.5), 42% and 11% of patients had acute Grade 2 gastrourinary and gastrointestinal toxicity, respectively, with no Grade 3 or higher acute toxicity to date. Two patients experienced late Grade 3 GU toxicity. All patients are without evidence of biochemical or clinical progression to date, and favorably low PSA nadirs have been observed with a current median PSA nadir of 0.35 ng/mL (range, <0.01-2.1) for all patients (0.47 ng/mL, range, 0.2-2.1 for the monotherapy cohort; 0.10 ng/mL, range, 0.01-0.5 for the boost cohort). With a median follow-up of 48.6 months (range, 16.4-87.8), the comparable HDR brachytherapy boost cohort has achieved a median PSA nadir of 0.09 ng/mL (range, 0.0-3.3). Conclusions: Early results with SBRT monotherapy and post-EBRT boost for PCa demonstrate acceptable PSA response and minimal toxicity. PSA nadir with SBRT boost appears comparable to those achieved with HDR brachytherapy boost.« less

Evaluation and mitigation of potential errors in radiochromic film dosimetry due to film curvature at scanning

PubMed Central

Bradley, David A.; Nisbet, Andrew

2015-01-01

This work considers a previously overlooked uncertainty present in film dosimetry which results from moderate curvature of films during the scanning process. Small film samples are particularly susceptible to film curling which may be undetected or deemed insignificant. In this study, we consider test cases with controlled induced curvature of film and with film raised horizontally above the scanner plate. We also evaluate the difference in scans of a film irradiated with a typical brachytherapy dose distribution with the film naturally curved and with the film held flat on the scanner. Typical naturally occurring curvature of film at scanning, giving rise to a maximum height 1 to 2 mm above the scan plane, may introduce dose errors of 1% to 4%, and considerably reduce gamma evaluation passing rates when comparing film‐measured doses with treatment planning system‐calculated dose distributions, a common application of film dosimetry in radiotherapy. The use of a triple‐channel dosimetry algorithm appeared to mitigate the error due to film curvature compared to conventional single‐channel film dosimetry. The change in pixel value and calibrated reported dose with film curling or height above the scanner plate may be due to variations in illumination characteristics, optical disturbances, or a Callier‐type effect. There is a clear requirement for physically flat films at scanning to avoid the introduction of a substantial error source in film dosimetry. Particularly for small film samples, a compression glass plate above the film is recommended to ensure flat‐film scanning. This effect has been overlooked to date in the literature. PACS numbers: 87.55.Qr, 87.56.bg, 87.55.km PMID:26103181

Automatic C-arm pose estimation via 2D/3D hybrid registration of a radiographic fiducial

NASA Astrophysics Data System (ADS)

Moult, E.; Burdette, E. C.; Song, D. Y.; Abolmaesumi, P.; Fichtinger, G.; Fallavollita, P.

2011-03-01

Motivation: In prostate brachytherapy, real-time dosimetry would be ideal to allow for rapid evaluation of the implant quality intra-operatively. However, such a mechanism requires an imaging system that is both real-time and which provides, via multiple C-arm fluoroscopy images, clear information describing the three-dimensional position of the seeds deposited within the prostate. Thus, accurate tracking of the C-arm poses proves to be of critical importance to the process. Methodology: We compute the pose of the C-arm relative to a stationary radiographic fiducial of known geometry by employing a hybrid registration framework. Firstly, by means of an ellipse segmentation algorithm and a 2D/3D feature based registration, we exploit known FTRAC geometry to recover an initial estimate of the C-arm pose. Using this estimate, we then initialize the intensity-based registration which serves to recover a refined and accurate estimation of the C-arm pose. Results: Ground-truth pose was established for each C-arm image through a published and clinically tested segmentation-based method. Using 169 clinical C-arm images and a +/-10° and +/-10 mm random perturbation of the ground-truth pose, the average rotation and translation errors were 0.68° (std = 0.06°) and 0.64 mm (std = 0.24 mm). Conclusion: Fully automated C-arm pose estimation using a 2D/3D hybrid registration scheme was found to be clinically robust based on human patient data.

Long-Term Results of Brachytherapy With Temporary Iodine-125 Seeds in Children With Low-Grade Gliomas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korinthenberg, Rudolf, E-mail: rudolf.korinthenberg@uniklinik-freiburg.d; Neuburger, Daniela; Trippel, Michael

Purpose: To retrospectively review the results of temporary I-125 brachytherapy in 94 children and adolescents with low-grade glioma. Methods and Materials: Treatment was performed in progressive tumors roughly spherical in shape with a diameter of up to 5 cm, including 79 astrocytomas, 5 oligodendrogliomas, 4 oligoastrocytomas, 1 ependymoma, and 5 other tumors. Location was suprasellar/chiasmal in 44, thalamic/basal ganglia in 18, hemispheric in 15, midbrain/pineal region in 13, and lower brainstem in 3. Initially, 8% of patients were free of symptoms, 47% were symptomatic but not disabled, and 30% were slightly, 6% moderately, and 3% severely disabled. Results: 5- andmore » 10-year survival was 97% and 92%. The response to I-125 brachytherapy over the long term was estimated after a median observation period of 38.4 (range, 6.4-171.0) months. At that time, 4 patients were in complete, 27 in partial, and 18 in objective remission; 15 showed stable and 30 progressive tumors. Treatment results did not correlate with age, sex, histology, tumor size, location, or demarcation of the tumor. Secondary treatment became necessary in 36 patients, including 19 who underwent repeated I-125 brachytherapy. At final follow-up, the number of symptom-free patients had risen to 21%. Thirty-eight percent showed symptoms without functional impairment, 19% were slightly and 11% moderately disabled, and only 4% were severely disabled. Conclusions: Response rates similar to those of conventional radiotherapy or chemotherapy can be anticipated with I-125 brachytherapy in tumors of the appropriate size and shape. We believe it to be a useful contribution to the treatment of low-grade gliomas in children.« less

Can IMRT or Brachytherapy Reduce Dysphagia Associated With Chemoradiotherapy of Head and Neck Cancer? The Michigan and Rotterdam Experiences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisbruch, Avraham; Levendag, Peter C.; Feng, Felix Y.

Purpose: Dysphagia is a major late complication of intensive chemoradiotherapy of head and neck cancer. The initial clinical results of intensity-modulated radiotherapy (IMRT), or brachytherapy, planned specifically to reduce dysphagia are presented. Patients and Methods: Previous research at Michigan University has suggested that the pharyngeal constrictors and glottic and supraglottic larynx are likely structures whose damage by chemo-RT causes dysphagia and aspiration. In a prospective Michigan trial, 36 patients with oropharyngeal (n = 31) or nasopharyngeal (n = 5) cancer underwent chemo-IMRT. IMRT cost functions included sparing noninvolved pharyngeal constrictors and the glottic and supraglottic larynx. After a review ofmore » published studies, the retropharyngeal nodes at risk were defined as the lateral, but not the medial, retropharyngeal nodes, which facilitated sparing of the swallowing structures. In Rotterdam, 77 patients with oropharyngeal cancer were treated with IMRT, three dimensional RT, or conventional RT; also one-half received brachytherapy. The dysphagia endpoints included videofluoroscopy and observer-assessed scores at Michigan and patient-reported quality-of-life instruments in both studies. Results: In both studies, the doses to the upper and middle constrictors correlated highly with the dysphagia endpoints. In addition, doses to the glottic and supraglottic larynx were significant in the Michigan series. In the Rotterdam series, brachytherapy (which reduced the doses to the swallowing structures) was the only significant factor on multivariate analysis. Conclusion: The dose-response relationships for the swallowing structures found in these studies suggest that reducing their doses, using either IMRT aimed at their sparing, or brachytherapy, might achieve clinical gains in dysphagia.« less

Low-dose rate prostate brachytherapy is well tolerated in patients with a history of inflammatory bowel disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peters, Christopher A.; Cesaretti, Jamie A.; Stone, Nelson N.

2006-10-01

Purpose: We report on the follow-up of 24 patients with a prior history of inflammatory bowel disease (IBD) treated with brachytherapy for early-stage prostate cancer. Methods and Materials: Twenty-four patients with a history of inflammatory bowel disease (17 with ulcerative colitis (UC), 7 with Crohn's disease [CD]) underwent prostate brachytherapy between 1992 and 2004. Fifteen patients were treated with I-125 implantation and 6 patients were treated with Pd-103 alone or in combination with 45 Gy external beam radiation. Charts were reviewed for all patients, and all living patients were contacted by phone. National Cancer Institute common toxicity scores for proctitismore » were assigned to all patients. Actuarial risk of late toxicity was calculated by the Kaplan-Meier method. Statistical analysis was performed using SPSS software. Follow-up ranged from 3 to 126 months (median, 48.5 months; mean, 56.8 months). Results: None of the patients experienced Grade 3 or 4 rectal toxicity. Four patients experienced Grade 2 late rectal toxicity. The 5-year actuarial freedom from developing late Grade 2 rectal toxicity was 81%. At a median follow-up of 48.5 months, 23 patients were alive and had no evidence of disease with a median prostate-specific antigen for the sample of 0.1 ng/mL (range, <0.05-0.88 ng/mL). One patient died of other causes unrelated to his prostate cancer. Conclusions: Prostate brachytherapy is well tolerated in patients with a history of controlled IBD. Therefore, brachytherapy should be considered a viable therapeutic option in this patient population.« less

Prostate cancer-specific mortality and the extent of therapy in healthy elderly men with high-risk prostate cancer.

PubMed

Hoffman, Karen E; Chen, Ming-Hui; Moran, Brian J; Braccioforte, Michelle H; Dosoretz, Daniel; Salenius, Sharon; Katin, Michael J; Ross, Rudi; D'Amico, Anthony V

2010-06-01

The risk of prostate cancer-specific mortality (PCSM) in healthy elderly men may depend on extent of treatment. The authors of this report compared the use of brachytherapy alone with combined brachytherapy, external-beam radiation to the prostate and seminal vesicles, and androgen-suppression therapy (CMT) in this population. The study cohort comprised 764 men aged > or = 65 years with high-risk prostate cancer (T3 or T4N0M0, prostate-specific antigen >20 ng/mL, and/or Gleason score 8-10) who received either brachytherapy alone (n = 206) or CMT (n = 558) at the Chicago Prostate Cancer Center or at a 21st Century Oncology facility. Men either had no history of myocardial infarction (MI) or had a history of MI treated with a stent or surgical intervention. Fine and Gray regression analysis was used to identify the factors associated with PCSM. The median patient age was 73 years (interquartile range, 70-77 years). After a median follow-up of 4.9 years, 25 men died of prostate cancer. After adjusting for age and prostate cancer prognostic factors, the risk of PCSM was significantly less (adjusted hazard ratio, 0.29; 95% confidence interval, 0.12-0.68; P = .004) for men who received CMT than for men who received brachytherapy alone. Other factors that were associated significantly with an increased risk of PCSM included a Gleason score of 8 to 10 (P = .017). Elderly men who had high-risk prostate cancer without cardiovascular disease or with surgically corrected cardiovascular disease had a lower risk of PCSM when they received CMT than when they received brachytherapy alone. These results support aggressive locoregional treatment in healthy elderly men with high-risk prostate cancer. (c) 2010 American Cancer Society.

A retrospective analysis of rectal and bladder dose for gynecological brachytherapy treatments with GZP6 HDR afterloading system.

PubMed

Bahreyni Toossi, Mohammad Taghi; Ghorbani, Mahdi; Makhdoumi, Yasha; Taheri, Mojtaba; Homaee Shandiz, Fatemeh; Zahed Anaraki, Siavash; Soleimani Meigooni, Ali

2012-01-01

The aim of this work is to evaluate rectal and bladder dose for the patients treated for gynecological cancers. The GZP6 high dose rate brachytherapy system has been recently introduced to a number of radiation therapy departments in Iran, for treatment of various tumor sites such as cervix and vagina. Our analysis was based on dose measurements for 40 insertions in 28 patients, treated by a GZP6 unit between June 2009 and November 2010. Treatments consisted of combined teletherapy and intracavitary brachytherapy. In vivo dosimetry was performed with TLD-400 chips and TLD-100 microcubes in the rectum and bladder. The average of maximum rectal and bladder dose values were found to be 7.62 Gy (range 1.72-18.55 Gy) and 5.17 Gy (range 0.72-15.85 Gy), respectively. It has been recommended by the ICRU that the maximum dose to the rectum and bladder in intracavitary treatment of vaginal or cervical cancer should be lower than 80% of the prescribed dose to point A in the Manchester system. In this study, of the total number of 40 insertions, maximum rectal dose in 29 insertions (72.5% of treatment sessions) and maximum bladder dose in 18 insertions (45% of treatments sessions) were higher than 80% of the prescribed dose to the point of dose prescription. In vivo dosimetry for patients undergoing treatment by GZP6 brachytherapy system can be used for evaluation of the quality of brachytherapy treatments by this system. This information could be used as a base for developing the strategy for treatment of patients treated with GZP6 system.

A retrospective analysis of rectal and bladder dose for gynecological brachytherapy treatments with GZP6 HDR afterloading system

PubMed Central

Bahreyni Toossi, Mohammad Taghi; Ghorbani, Mahdi; Makhdoumi, Yasha; Taheri, Mojtaba; Homaee Shandiz, Fatemeh; Zahed Anaraki, Siavash; Soleimani Meigooni, Ali

2012-01-01

Aim The aim of this work is to evaluate rectal and bladder dose for the patients treated for gynecological cancers. Background The GZP6 high dose rate brachytherapy system has been recently introduced to a number of radiation therapy departments in Iran, for treatment of various tumor sites such as cervix and vagina. Materials and methods Our analysis was based on dose measurements for 40 insertions in 28 patients, treated by a GZP6 unit between June 2009 and November 2010. Treatments consisted of combined teletherapy and intracavitary brachytherapy. In vivo dosimetry was performed with TLD-400 chips and TLD-100 microcubes in the rectum and bladder. Results The average of maximum rectal and bladder dose values were found to be 7.62 Gy (range 1.72–18.55 Gy) and 5.17 Gy (range 0.72–15.85 Gy), respectively. It has been recommended by the ICRU that the maximum dose to the rectum and bladder in intracavitary treatment of vaginal or cervical cancer should be lower than 80% of the prescribed dose to point A in the Manchester system. In this study, of the total number of 40 insertions, maximum rectal dose in 29 insertions (72.5% of treatment sessions) and maximum bladder dose in 18 insertions (45% of treatments sessions) were higher than 80% of the prescribed dose to the point of dose prescription. Conclusion In vivo dosimetry for patients undergoing treatment by GZP6 brachytherapy system can be used for evaluation of the quality of brachytherapy treatments by this system. This information could be used as a base for developing the strategy for treatment of patients treated with GZP6 system. PMID:24377037

Optimization for high-dose-rate brachytherapy of cervical cancer with adaptive simulated annealing and gradient descent.

PubMed

Yao, Rui; Templeton, Alistair K; Liao, Yixiang; Turian, Julius V; Kiel, Krystyna D; Chu, James C H

2014-01-01

To validate an in-house optimization program that uses adaptive simulated annealing (ASA) and gradient descent (GD) algorithms and investigate features of physical dose and generalized equivalent uniform dose (gEUD)-based objective functions in high-dose-rate (HDR) brachytherapy for cervical cancer. Eight Syed/Neblett template-based cervical cancer HDR interstitial brachytherapy cases were used for this study. Brachytherapy treatment plans were first generated using inverse planning simulated annealing (IPSA). Using the same dwell positions designated in IPSA, plans were then optimized with both physical dose and gEUD-based objective functions, using both ASA and GD algorithms. Comparisons were made between plans both qualitatively and based on dose-volume parameters, evaluating each optimization method and objective function. A hybrid objective function was also designed and implemented in the in-house program. The ASA plans are higher on bladder V75% and D2cc (p=0.034) and lower on rectum V75% and D2cc (p=0.034) than the IPSA plans. The ASA and GD plans are not significantly different. The gEUD-based plans have higher homogeneity index (p=0.034), lower overdose index (p=0.005), and lower rectum gEUD and normal tissue complication probability (p=0.005) than the physical dose-based plans. The hybrid function can produce a plan with dosimetric parameters between the physical dose-based and gEUD-based plans. The optimized plans with the same objective value and dose-volume histogram could have different dose distributions. Our optimization program based on ASA and GD algorithms is flexible on objective functions, optimization parameters, and can generate optimized plans comparable with IPSA. Copyright © 2014 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Brachytherapy for conservative treatment of invasive penile carcinoma in older patients: Single institution experience.

PubMed

Escande, Alexandre; Maroun, Pierre; Dumas, Isabelle; Schernberg, Antoine; Bossi, Alberto; De Crevoisier, Renaud; Deutsch, Eric; Haie-Meder, Christine; Chargari, Cyrus

2018-05-01

No study has examined the possibility to perform an organ sparing strategy in older patients with penile carcinoma, and amputation is frequently proposed. We report our experience of interstitial brachytherapy for the conservative treatment of penile carcinoma confined to the glans in patients aged of 70years and more. A total of 55 patients candidates to conservative brachytherapy were identified. Median age was 73.8years (range: 70-95years). Patients underwent a circumcision then 3-4weeks later, an interstitial brachytherapy was delivered, median dose of 65Gy (range 55-74Gy). Salvage surgery was discussed in patients with histological confirmation of residual/relapsed tumor. With median follow-up of 9.0years, eight patients (14.5%) experienced a relapse, including five patients with local relapse. Three patients with local relapse only underwent salvage penile surgery, including two partial glansectomies and one total penectomy, and were in second complete remission at last follow-up. Among 55 patients analyzed for late side effects, seven patients (13.0%) presented pain or ulceration, 12 (22.2%) experienced urethral or meatal stenosis requiring at least one dilatation, two patients (3.7%) experienced both ulcerations and urethral complication. Three patients (5.5%) needed partial glansectomy for focal necrosis. At five years, estimated overall survival rate was 74.5% (95%CI: 62.0-87.0%) and local relapse free rate was 91.0% (95%CI: 82.6-99.4%). Brachytherapy is feasible in selected older patients with penile carcinoma, with efficacy and toxicity rates comparable to that of other series in younger patients. Copyright © 2017 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shaitelman, Simona F., E-mail: sfshaitelman@mdanderson.org; Lin, Heather Y.; Smith, Benjamin D.

Purpose: To examine utilization trends of accelerated partial breast irradiation (APBI) in the American College of Surgeons' National Cancer Database and changes in APBI use after the 2009 publication of the American Society for Radiation Oncology (ASTRO) guidelines. Methods and Materials: A total of 399,705 women were identified who were diagnosed from 2004 to 2011 with nonmetastatic invasive breast cancer or ductal carcinoma in situ who were treated with breast-conserving surgery and radiation therapy to the breast. Patients were divided by the type of treatment received (whole breast irradiation or APBI) and by suitability to receive APBI as defined bymore » the ASTRO guidelines. Logistic regression was applied to study APBI use overall and within guideline categorization, and a multivariable model was created to determine predictors of treatment with brachytherapy-based APBI based on guideline categorization. Results: For all patients, APBI use increased, from 3.8% in 2004 to 10.6% in 2011 (P<.0001). Overall rates of APBI utilization were higher among “suitable” than “cautionary”/“unsuitable” patients (14.8% vs 7.1%, P<.0001). The majority of APBI treatment was delivered using brachytherapy, for which use peaked in 2008. Starting in 2009, among “suitable” patients, utilization of APBI via brachytherapy plateaued, whereas for “cautionary”/“unsuitable” patients, treatment with brachytherapy-based APBI declined and then plateaued. Conclusion: Use of APBI across all patient groups increased from 2004 through 2008. After publication of the ASTRO APBI guidelines in 2009, rates of brachytherapy-based APBI treatment plateaued among “suitable” patients and declined and then plateaued among “cautionary”/“unsuitable” patients. Our study highlights how large national databases can be used to assess national trends in radiation use in response to the publication of guidelines.« less

Commissioning of a well type chamber for HDR and LDR brachytherapy applications: a review of methodology and outcomes.

PubMed

Mukwada, Godfrey; Neveri, Gabor; Alkhatib, Zaid; Waterhouse, David K; Ebert, Martin

2016-03-01

For safe and accurate dose delivery in brachytherapy, associated equipment is subject to commissioning and ongoing quality assurance (QA). Many centres depend on the use of a well-type chamber ('well chamber') for performing brachytherapy dosimetry. Documentation of well chamber commissioning is scarce despite the important role the chamber plays in the whole brachytherapy QA process. An extensive and structured commissioning of the HDR 1000 plus well chamber (Standard Imaging Inc, Middleton WI) for HDR and LDR dosimetry was undertaken at Sir Charles Gairdner Hospital. The methodology and outcomes of this commissioning is documented and presented as a guideline to others involved in brachytherapy. The commissioning tests described include mechanical integrity, leakage current, directional dependence, response, length of uniform response, the influence of insert holders, ion collection efficiency, polarity effect, accuracy of measured air kerma strength (S(K)) or reference air kerma rate (K(R)) and baseline setting (for ongoing constancy checks). For the HDR 1000 plus well chamber, some of the insert holders modify the response curve. The measured sweet length was 2.5 cm which is within 0.5% of that specified by the manufacturer. Correction for polarity was negligible (0.9999) and ion recombination was small (0.9994). Directional dependence was small (less than 0.2%) and leakage current was negligible. The measured K(R) for (192)Ir agreed within 0.11% compared with a second well chamber of similar model and was within 0.5% of that determined via a free-in-air measurement method. Routine constancy checks over a year agreed with the baseline within 0.4%.

Design and optimization of a brachytherapy robot

NASA Astrophysics Data System (ADS)

Meltsner, Michael A.

Trans-rectal ultrasound guided (TRUS) low dose rate (LDR) interstitial brachytherapy has become a popular procedure for the treatment of prostate cancer, the most common type of non-skin cancer among men. The current TRUS technique of LDR implantation may result in less than ideal coverage of the tumor with increased risk of negative response such as rectal toxicity and urinary retention. This technique is limited by the skill of the physician performing the implant, the accuracy of needle localization, and the inherent weaknesses of the procedure itself. The treatment may require 100 or more sources and 25 needles, compounding the inaccuracy of the needle localization procedure. A robot designed for prostate brachytherapy may increase the accuracy of needle placement while minimizing the effect of physician technique in the TRUS procedure. Furthermore, a robot may improve associated toxicities by utilizing angled insertions and freeing implantations from constraints applied by the 0.5 cm-spaced template used in the TRUS method. Within our group, Lin et al. have designed a new type of LDR source. The "directional" source is a seed designed to be partially shielded. Thus, a directional, or anisotropic, source does not emit radiation in all directions. The source can be oriented to irradiate cancerous tissues while sparing normal ones. This type of source necessitates a new, highly accurate method for localization in 6 degrees of freedom. A robot is the best way to accomplish this task accurately. The following presentation of work describes the invention and optimization of a new prostate brachytherapy robot that fulfills these goals. Furthermore, some research has been dedicated to the use of the robot to perform needle insertion tasks (brachytherapy, biopsy, RF ablation, etc.) in nearly any other soft tissue in the body. This can be accomplished with the robot combined with automatic, magnetic tracking.

Study of two different radioactive sources for prostate brachytherapy treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pereira Neves, Lucio; Perini, Ana Paula; Souza Santos, William de

In this study we evaluated two radioactive sources for brachytherapy treatments. Our main goal was to quantify the absorbed doses on organs and tissues of an adult male patient, submitted to a brachytherapy treatment with two radioactive sources. We evaluated a {sup 192}Ir and a {sup 125}I radioactive sources. The {sup 192}Ir radioactive source is a cylinder with 0.09 cm in diameter and 0.415 cm long. The {sup 125}I radioactive source is also a cylinder, with 0.08 cm in diameter and 0.45 cm long. To evaluate the absorbed dose distribution on the prostate, and other organs and tissues of anmore » adult man, a male virtual anthropomorphic phantom MASH, coupled in the radiation transport code MCNPX 2.7.0, was employed.We simulated 75, 90 and 102 radioactive sources of {sup 125}I and one of {sup 192}Ir, inside the prostate, as normally used in these treatments, and each treatment was simulated separately. As this phantom was developed in a supine position, the displacement of the internal organs of the chest, compression of the lungs and reduction of the sagittal diameter were all taken into account. For the {sup 192}Ir, the higher doses values were obtained for the prostate and surrounding organs, as the colon, gonads and bladder. Considering the {sup 125}I sources, with photons with lower energies, the doses to organs that are far from the prostate were lower. All values for the dose rates are in agreement with those recommended for brachytherapy treatments. Besides that, the new seeds evaluated in this work present usefulness as a new tool in prostate brachytherapy treatments, and the methodology employed in this work may be applied for other radiation sources, or treatments. (authors)« less

Reference air kerma rate calibration system for high dose rate Ir-192 brachytherapy sources in Taiwan

NASA Astrophysics Data System (ADS)

Chu, Wei-Han; Yuan, Ming-Chen; Lee, Jeng-Hung; Lin, Yi-Chun

2017-11-01

Ir-192 sources are widely used in brachytherapy and the number of treatments is around seven thousand for the use of the high dose rate (HDR) Ir-192 brachytherapy source per year in Taiwan. Due to its physical half-life of 73.8 days, the source should be replaced four times per year to maintain the HDR treatment mode (DDEP, 2005; Coursey et al., 1992). When doing this work, it must perform the source dose trace to assure the dose accuracy. To establish the primary measurement standard of reference air kerma rate(RAKR) for the HDR Ir-192 brachytherapy sources in Taiwan, the Institute of Nuclear Energy Research (INER) fabricated a dual spherical graphite-walled cavity ionization chambers system to directly measure the RAKR of the Ir-192 brachytherapy source. In this system, the ion-charge was accumulated by the two ionization chambers and after correction for the ion recombination, temperature, atmosphere pressure, room scattering, graphite-wall attenuation, air attenuation, source decay, stem effect, and so on. The RAKR of the Ir-192 source was obtained in the ambient conditions of 22 °C and one atmosphere. The measurement uncertainty of the system was around 0.92% in 96% confidence level (k=2.0). To verify the accuracy of the result, the source calibration comparison has been made at the National Radiation Standard Laboratory (NRSL) of INER and Physikalisch-Technische Bundesanstalt (PTB, Germany) in 2015. The ratio of the measurement results between INER and PTB, INER/PTB, was 0.998±0.027 (k=2) which showed good consistency and the performance of the system was verified.

High-risk CTV delineation for cervix brachytherapy: Application of GEC-ESTRO guidelines in Australia and New Zealand.

PubMed

Vinod, Shalini K; Lim, Karen; Bell, Lauren; Veera, Jacqueline; Ohanessian, Lucy; Juresic, Ewa; Borok, Nira; Chan, Phillip; Chee, Raphael; Do, Viet; Govindarajulu, Geetha; Sridharan, Swetha; Johnson, Carol; Moses, Daniel; Van Dyk, Sylvia; Holloway, Lois

2017-02-01

Image-based brachytherapy for cervical cancer using MRI has been implemented in Australia and New Zealand. The aims of this study were to measure variability in High-risk CTV (HR-CTV) delineation and evaluate dosimetric consequences of this. Nine radiation oncologists, one radiation therapist and two radiologists contoured HR-CTV on 3T MRI datasets from ten consecutive patients undergoing cervical brachytherapy at a single institution. Contour comparisons were performed using the Dice Similarity Coefficient (DSC) and Mean Absolute Surface Distance (MASD). Two reference contours were created for brachytherapy planning: a Simultaneous Truth and Performance Level Estimation (STAPLE) and a consensus contour (CONSENSUS). Optimized plans (8 Gy) for both these contours were applied to individual participant's contours to assess D90 and D100 coverage of HR CTV. To compare variability in dosimetry, relative standard deviation (rSD) was calculated. Good concordance (mean DSC≥0.7, MASD≤5 mm) was achieved in 8/10 cases when compared to the STAPLE reference and 6/10 cases when compared to the CONSENSUS reference. Greatest variation was visually seen in the cranio-caudal direction. The average mean rSD across all patients was 27% and 34% for the STAPLE HR-CTV D90 and D100, respectively, and 28% and 35% for the CONSENSUS HR-CTV D90 and D100. Delineation uncertainty resulted in an average dosimetric uncertainty of ±1.5-1.6 Gy per fraction based on an 8 Gy prescribed fraction. Delineation of HR-CTV for cervical cancer brachytherapy was consistent amongst observers, suggesting similar interpretation of GEC-ESTRO guidelines. Despite the good concordance, there was dosimetric variation noted, which could be clinically significant. © 2016 The Royal Australian and New Zealand College of Radiologists.

Erectile Function Durability Following Permanent Prostate Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taira, Al V.; Merrick, Gregory S., E-mail: gmerrick@urologicresearchinstitute.or; Galbreath, Robert W.

2009-11-01

Purpose: To evaluate long-term changes in erectile function following prostate brachytherapy. Methods and Materials: This study included 226 patients with prostate cancer and preimplant erectile function assessed by the International Index of Erectile Function-6 (IIEF-6) who underwent brachytherapy in two prospective randomized trials between February 2001 and January 2003. Median follow-up was 6.4 years. Pre- and postbrachytherapy potency was defined as IIEF-6 >= 13 without pharmacologic or mechanical support. The relationship among clinical, treatment, and dosimetric parameters and erectile function was examined. Results: The 7-year actuarial rate of potency preservation was 55.6% with median postimplant IIEF of 22 in potentmore » patients. Potent patients were statistically younger (p = 0.014), had a higher preimplant IIEF (p < 0.001), were less likely to be diabetic (p = 0.002), and were more likely to report nocturnal erections (p = 0.008). Potency preservation in men with baseline IIEF scores of 29-30, 24-28, 18-23, and 13-17 were 75.5% vs. 73.6%, 51.7% vs. 44.8%, 48.0% vs. 40.0%, and 23.5% vs. 23.5% in 2004 vs. 2008. In multivariate Cox regression analysis, preimplant IIEF, hypertension, diabetes, prostate size, and brachytherapy dose to proximal penis strongly predicted for potency preservation. Impact of proximal penile dose was most pronounced for men with IIEF of 18-23 and aged 60-69. A significant minority of men who developed postimplant impotence ultimately regained erectile function. Conclusion: Potency preservation and median IIEF scores following brachytherapy are durable. Thoughtful dose sparing of proximal penile structures and early penile rehabilitation may further improve these results.« less

The Effects of Metallic Implants on Electroporation Therapies: Feasibility of Irreversible Electroporation for Brachytherapy Salvage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neal, Robert E., E-mail: robert.neal@alfred.org.au; Smith, Ryan L., E-mail: ryan.smith@wbrc.org.au; Kavnoudias, Helen, E-mail: H.Kavnoudias@alfred.org.au

2013-12-15

Purpose: Electroporation-based therapies deliver brief electric pulses into a targeted volume to destabilize cellular membranes. Nonthermal irreversible electroporation (IRE) provides focal ablation with effects dependent on the electric field distribution, which changes in heterogeneous environments. It should be determined if highly conductive metallic implants in targeted regions, such as radiotherapy brachytherapy seeds in prostate tissue, will alter treatment outcomes. Theoretical and experimental models determine the impact of prostate brachytherapy seeds on IRE treatments. Materials and Methods: This study delivered IRE pulses in nonanimal, as well as in ex vivo and in vivo tissue, with and in the absence of expiredmore » radiotherapy seeds. Electrical current was measured and lesion dimensions were examined macroscopically and with magnetic resonance imaging. Finite-element treatment simulations predicted the effects of brachytherapy seeds in the targeted region on electrical current, electric field, and temperature distributions. Results: There was no significant difference in electrical behavior in tissue containing a grid of expired radiotherapy seeds relative to those without seeds for nonanimal, ex vivo, and in vivo experiments (all p > 0.1). Numerical simulations predict no significant alteration of electric field or thermal effects (all p > 0.1). Histology showed cellular necrosis in the region near the electrodes and seeds within the ablation region; however, there were no seeds beyond the ablation margins. Conclusion: This study suggests that electroporation therapies can be implemented in regions containing small metallic implants without significant changes to electrical and thermal effects relative to use in tissue without the implants. This supports the ability to use IRE as a salvage therapy option for brachytherapy.« less

Combination of biodegradable stent placement and single-dose brachytherapy is associated with an unacceptably high complication rate in the treatment of dysphagia from esophageal cancer.

PubMed

Hirdes, Meike M C; van Hooft, Jeanin E; Wijrdeman, Harm K; Hulshof, Maarten C C M; Fockens, Paul; Reerink, Onne; van Oijen, Martijn G H; van der Tweel, Ingeborg; Vleggaar, Frank P; Siersema, Peter D

2012-08-01

For the palliative treatment of dysphagia, esophageal stent placement provides immediate improvement, whereas brachytherapy offers better long-term relief. To evaluate safety and efficacy of concurrent brachytherapy and biodegradable stent placement. Prospective, single-arm study. Two tertiary-care referral centers. Nineteen consecutive patients with significant dysphagia resulting from unresectable esophageal cancer, with a life expectancy of more than 3 months. Single-dose brachytherapy (12 Gy) on day 1 followed by biodegradable stent placement on day 2. Intervention-related major complications (determined by an expert panel) and dysphagia. Nineteen patients (13 men, median age 66 years [interquartile range (IQR) 59-71] years) were included; 7 patients (37%) also received palliative chemotherapy. After inclusion of 19 patients, the study was ended prematurely because the safety threshold was exceeded. In total, 28 major complications occurred in 17 patients (89%). In 9 patients (47%), major complications were determined intervention-related (severe retrosternal pain with or without vomiting [n = 6], hematemesis [n = 1], recurrent dysphagia [n = 2]. Dysphagia scores decreased significantly from a median of 3 (IQR 3-4) to a median of 1 (IQR 0-3) after 1 month (P < .001). Despite adequate luminal patency in 17 patients (89%), normal diet could not be tolerated in 7 patients (37%) because of retrosternal pain and vomiting. Lack of routine endoscopy or contrast esophagram to evaluate recurrent dysphagia during follow-up. Despite restoration of luminal patency, a combined treatment of brachytherapy and biodegradable stent placement cannot be recommended for the palliative treatment of esophageal cancer because of an unacceptably high intervention-related major complication rate. Copyright © 2012 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

Exeresis and Brachytherapy as Salvage Treatment for Local Recurrence After Conservative Treatment for Breast Cancer: Results of a Ten-Year Pilot Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guix, Benjamin, E-mail: bguix@imor.or; Lejarcegui, Jose Antonio; Tello, Jose Ignacio

2010-11-01

Purpose: To analyze the long-term results of a pilot study assessing excision and brachytherapy as salvage treatment for local recurrence after conservative treatment of breast cancer. Methods and Materials: Between December 1990 and March 2001, 36 patients with breast-only recurrence less than 3 cm in diameter after conservative treatment for Stage I or II breast carcinoma were treated with local excision followed by high-dose rate brachytherapy implants (30 Gy in 12 fractions over a period of 5 days). No patient was lost to follow-up. Special attention was paid to local, regional, or distant recurrences; survival; cosmesis; and early and latemore » side effects. Results: All patients completed treatment. During follow-up (range, 1-13 years), 8 patients presented metastases (2 regional and 6 distant) as their first site of failure, 1 had a differed local recurrence, and 1 died of the disease. Actuarial results at 10 years were as follows: local control, 89.4%; disease-free survival, 64.4%; and survival, 96.7%. Cosmetic results were satisfactory in 90.4%. No patient had Grade 3 or 4 early or late complications. Of the 11 patients followed up for at least 10 years, all but 1 still had their breast in place at the 10-year stage. Conclusions: High-dose rate brachytherapy is a safe, effective treatment for small-size, low-risk local recurrence after local excision in conservatively treated patients. The dose of 30 Gy of high-dose rate brachytherapy (12 fractions over a period of 5 days twice daily) was well tolerated. The excellent results support the use of breast preservation as salvage treatment in selected patients with local recurrence after conservative treatment for breast cancer.« less

A national survey of HDR source knowledge among practicing radiation oncologists and residents: Establishing a willingness-to-pay threshold for cobalt-60 usage.

PubMed

Mailhot Vega, Raymond; Talcott, Wesley; Ishaq, Omar; Cohen, Patrice; Small, Christina J; Duckworth, Tamara; Sarria Bardales, Gustavo; Perez, Carmen A; Schiff, Peter B; Small, William; Harkenrider, Matthew M

Ir-192 is the predominant source for high-dose-rate (HDR) brachytherapy in United States markets. Co-60, with longer half-life and fewer source exchanges, has piloted abroad with comparable clinical dosimetry but increased shielding requirements. We sought to identify practitioner knowledge of Co-60 and establish acceptable willingness-to-pay (WTP) thresholds for additional shielding requirements for use in future cost-benefit analysis. A nationwide survey of U.S. radiation oncologists was conducted from June to July 2015, assessing knowledge of HDR sources, brachytherapy unit shielding, and factors that may influence source-selection decision-making. Self-identified decision makers in radiotherapy equipment purchase and acquisition were asked their WTP on shielding should a more cost-effective source become available. Four hundred forty surveys were completed and included. Forty-four percent were ABS members. Twenty percent of respondents identified Co-60 as an HDR source. Respondents who identified Co-60 were significantly more likely to be ABS members, have attended a national brachytherapy conference, and be involved in brachytherapy selection. Sixty-six percent of self-identified decision makers stated that their facility would switch to a more cost-effective source than Ir-192, if available. Cost and experience were the most common reasons provided for not switching. The most common WTP value selected by respondents was <$25,000. A majority of respondents were unaware of Co-60 as a commercially available HDR source. This investigation was novel in directly assessing decision makers to establish WTP for shielding costs that source change to Co-60 may require. These results will be used to establish WTP threshold for future cost-benefit analysis. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Young Men Have Equivalent Biochemical Outcomes Compared With Older Men After Treatment With Brachytherapy for Prostate Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burri, Ryan J.; Ho, Alice Y.; Forsythe, Kevin

Purpose: To evaluate retrospectively the biochemical outcomes of young men treated with low-dose-rate brachytherapy for prostate cancer. Methods and Materials: From 1990 to 2005, 1,665 men with clinically localized prostate cancer were treated with low-dose-rate brachytherapy {+-} hormone therapy (HT) {+-} external beam radiotherapy and underwent {>=}2 years of follow-up. Patients were stratified on the basis of age: {<=}60 (n = 378) and >60 years (n = 1,287). Biochemical failure was defined as a prostate-specific antigen (PSA) nadir plus 2 ng/mL. Univariate and multivariate analyses were used to determine the association of variables with freedom from biochemical failure (FFbF). Results:more » Median follow-up was 68 months (range, 24-180) for men {<=}60 years and 66 months (range, 24-200) for men >60. For the entire group, the actuarial 5- and 8-year FFbF rates were 94% and 88%, respectively. Men {<=}60 demonstrated similar 5- and 8-year FFbF (95% and 92%) compared with men >60 (93% and 87%; p = 0.071). A larger percent of young patients presented with low-risk disease; lower clinical stage, Gleason score (GS), and pretreatment PSA values; were treated after 1997; did not receive any HT; and had a high biologic effective dose (BED) of radiation (all ps <0.001). On multivariate analysis, PSA (p = 0.001), GS (p = 0.005), and BED (p < 0.001) were significantly associated with FFbF, but age was not (p = 0.665). Conclusion: Young men achieve excellent 5- and 8-year biochemical control rates that are comparable to those of older men after prostate brachytherapy. Young age should not be a deterrent when considering brachytherapy as a primary treatment option for clinically localized prostate cancer.« less

Human error in airway facilities.

DOT National Transportation Integrated Search

2001-01-01

This report examines human errors in Airway Facilities (AF) with the intent of preventing these errors from being : passed on to the new Operations Control Centers. To effectively manage errors, they first have to be identified. : Human factors engin...

Latent human error analysis and efficient improvement strategies by fuzzy TOPSIS in aviation maintenance tasks.

PubMed

Chiu, Ming-Chuan; Hsieh, Min-Chih

2016-05-01

The purposes of this study were to develop a latent human error analysis process, to explore the factors of latent human error in aviation maintenance tasks, and to provide an efficient improvement strategy for addressing those errors. First, we used HFACS and RCA to define the error factors related to aviation maintenance tasks. Fuzzy TOPSIS with four criteria was applied to evaluate the error factors. Results show that 1) adverse physiological states, 2) physical/mental limitations, and 3) coordination, communication, and planning are the factors related to airline maintenance tasks that could be addressed easily and efficiently. This research establishes a new analytic process for investigating latent human error and provides a strategy for analyzing human error using fuzzy TOPSIS. Our analysis process complements shortages in existing methodologies by incorporating improvement efficiency, and it enhances the depth and broadness of human error analysis methodology. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purwaningsih, Anik

Dosimetric data for a brachytherapy source should be known before it used for clinical treatment. Iridium-192 source type H01 was manufactured by PRR-BATAN aimed to brachytherapy is not yet known its dosimetric data. Radial dose function and anisotropic dose distribution are some primary keys in brachytherapy source. Dose distribution for Iridium-192 source type H01 was obtained from the dose calculation formalism recommended in the AAPM TG-43U1 report using MCNPX 2.6.0 Monte Carlo simulation code. To know the effect of cavity on Iridium-192 type H01 caused by manufacturing process, also calculated on Iridium-192 type H01 if without cavity. The result ofmore » calculation of radial dose function and anisotropic dose distribution for Iridium-192 source type H01 were compared with another model of Iridium-192 source.« less

[Basic principles and results of brachytherapy in gynecological oncology].

PubMed

Kanaev, S V; Turkevich, V G; Baranov, S B; Savel'eva, V V

2014-01-01

The fundamental basics of contact radiation therapy (brachytherapy) for gynecological cancer are presented. During brachytherapy the principles of conformal radiotherapy should be implemented, the aim of which is to sum the maximum possible dose of radiation to the tumor and decrease the dose load in adjacent organs and tissues, which allows reducing the frequency of radiation damage at treatment of primary tumors. It is really feasible only on modern technological level, thanks to precision topometry preparation, optimal computer dosimetrical and radiobiological planning of each session and radiotherapy in general. Successful local and long-term results of the contact radiation therapy for cancer of cervix and endometrium are due to optimal anatomical and topometrical ratio of the tumor localization, radioactive sources, and also physical and radiobiological laws of distribution and effects of ionizing radiation, the dose load accounting rules.

Dosimetry for a uterine cervix cancer treatment

NASA Astrophysics Data System (ADS)

Rodríguez-Ponce, Miguel; Rodríguez-Villafuerte, Mercedes; Sánchez-Castro, Ricardo

2003-09-01

The dose distribution around the 3M 137Cs brachytherapy source as well as the same source inside the Amersham ASN 8231 applicator was measured using thermoluminescent dosimeters and radiochromic films. Some of the results were compared with those obtained from a Monte Carlo simulation and a good agreement was observed. The teletherapy dose distribution was measured using a pin-point ionization chamber. In addition, the experimental measurements and the Monte Carlo results were used to estimate the dose received in the rectum and bladder of an hypothetical patient treated with brachytherapy and compared with the dose distribution obtained from the Hospital's brachytherapy planning system. A 20 % dose reduction to the rectum and bladder was observed in both Monte Carlo and experimental measurements, compared with the results of the planning system, which results in a better dose control to these structures.

Reduction in radiation exposure to nursing personnel with the use of remote afterloading brachytherapy devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grigsby, P.W.; Perez, C.A.; Eichling, J.

The radiation exposure to nursing personnel from patients with brachytherapy implants on a large brachytherapy service were reviewed. Exposure to nurses, as determined by TLD monitors, indicates a 7-fold reduction in exposure after the implementation of the use of remote afterloading devices. Quarterly TLD monitor data for six quarters prior to the use of remote afterloading devices demonstrate an average projected annual dose equivalent to the nurses of 152 and 154 mrem (1.5 mSv). After the implementation of the remote afterloading devices, the quarterly TLD monitor data indicate an average dose equivalent per nurse of 23 and 19 mrem (0.2more » mSv). This is an 87% reduction in exposure to nurses with the use of these devices (p less than 0.01).« less

SU-E-T-169: Evaluation of Oncentra TPS for Nasopharynx Brachy Using Patient Specific Voxel Phantom and EGSnrc

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadad, K; Zoherhvand, M; Faghihi, R

2014-06-01

Purpose: Nasopharnx carcinoma (NPC) treatment is being carried out using Ir-192 HDR seeds in Mehdieh Hospital in Hamadan, Iran. The Oncentra™ TPS is based on optimized TG-43 formalism which disregards heterogeneity in the treatment area. Due to abundant heterogeneity in head and neck, comparison of the Oncentra™ TPS dose evaluation and an accurate dose calculation method in NPC brachytherapy is the objective of this study. Methods: CT DICOMs of a patient with NPC obtained from Mehdieh Hospital used to create 3D voxel phantom with CTCREATE utility of EGSnrc code package. The voxel phantom together with Ir-192 HDR brachytherapy source weremore » the input to DOSXYZnrc to calculate the 3D dose distribution. The sources were incorporate with type 6 source in DOSXYZnrc and their dwell times were taken into account in final dose calculations. Results: The direct comparison between isodoses as well as DVHs for the GTV, PTV and CTV obtained by Oncentra™ and EGSnrc Monte Carlo code are made. EGSnrc results are obtained using 5×10{sup 9} histories to reduce the statistical error below 1% in GTV and 5% in 5% dose areas. The standard ICRP700 cross section library is employed in DOSXYZnrc dose calculation. Conclusion: A direct relationship between increased dose differences and increased material density (hence heterogeneity) is observed when isodoses contours of the TPS and DOSXYZnrc are compared. Regarding the point dose calculations, the differences range from 1.2% in PTV to 5.6% for cavity region and 7.8% for bone regions. While Oncentra™ TPS overestimates the dose in cavities, it tends to underestimate dose depositions within bones.« less

Sci-Sat AM(2): Brachy-07: Tomosynthesis-based seed reconstruction in LDR prostate brachytherapy: A clinical study.

PubMed

Brunet-Benkhoucha, M; Verhaegen, F; Lassalle, S; Béliveau-Nadeau, D; Reniers, B; Donath, D; Taussky, D; Carrier, J-F

2008-07-01

To develop a tomosynthesis-based dose assessment procedure that can be performed after an I-125 prostate seed implantation, while the patient is still under anaesthesia on the treatment table. Our seed detection procedure involves the reconstruction of a volume of interest based on the backprojection of 7 seed-only binary images acquired over an angle of 60° with an isocentric imaging system. A binary seed-only volume is generated by a simple thresholding of the volume of interest. Seeds positions are extracted from this volume with a 3D connected component analysis and a statistical classifier that determines the number of seeds in each cluster of connected voxels. A graphical user interface (GUI) allows to visualize the result and to introduce corrections, if needed. A phantom and a clinical study (24 patients) were carried out to validate the technique. A phantom study demonstrated a very good localization accuracy of (0.4+/-0.4) mm when compared to CT-based reconstruction. This leads to dosimetric error on D90 and V100 of respectively 0.5% and 0.1%. In a patient study with an average of 56 seeds per implant, the automatic tomosynthesis-based reconstruction yields a detection rate of 96% of the seeds and less than 1.5% of false-positives. With the help of the GUI, the user can achieve a 100% detection rate in an average of 3 minutes. This technique would allow to identify possible underdosage and to correct it by potentially reimplanting additional seeds. A more uniform dose coverage could then be achieved in LDR prostate brachytherapy. © 2008 American Association of Physicists in Medicine.

Robot-assisted, ultrasound-guided minimally invasive navigation tool for brachytherapy and ablation therapy: initial assessment

NASA Astrophysics Data System (ADS)

Bhattad, Srikanth; Escoto, Abelardo; Malthaner, Richard; Patel, Rajni

2015-03-01

Brachytherapy and thermal ablation are relatively new approaches in robot-assisted minimally invasive interventions for treating malignant tumors. Ultrasound remains the most favored choice for imaging feedback, the benefits being cost effectiveness, radiation free, and easy access in an OR. However it does not generally provide high contrast, noise free images. Distortion occurs when the sound waves pass through a medium that contains air and/or when the target organ is deep within the body. The distorted images make it quite difficult to recognize and localize tumors and surgical tools. Often tools, such as a bevel-tipped needle, deflect from its path during insertion, making it difficult to detect the needle tip using a single perspective view. The shifting of the target due to cardiac and/or respiratory motion can add further errors in reaching the target. This paper describes a comprehensive system that uses robot dexterity to capture 2D ultrasound images in various pre-determined modes for generating 3D ultrasound images and assists in maneuvering a surgical tool. An interactive 3D virtual reality environment is developed that visualizes various artifacts present in the surgical site in real-time. The system helps to avoid image distortion by grabbing images from multiple positions and orientation to provide a 3D view. Using the methods developed for this application, an accuracy of 1.3 mm was achieved in target attainment in an in-vivo experiment subjected to tissue motion. An accuracy of 1.36 mm and 0.93 mm respectively was achieved for the ex-vivo experiments with and without external induced motion. An ablation monitor widget that visualizes the changes during the complete ablation process and enables evaluation of the process in its entirety is integrated.

Deformable registration of x-ray to MRI for post-implant dosimetry in prostate brachytherapy

NASA Astrophysics Data System (ADS)

Park, Seyoun; Song, Danny Y.; Lee, Junghoon

2016-03-01

Post-implant dosimetric assessment in prostate brachytherapy is typically performed using CT as the standard imaging modality. However, poor soft tissue contrast in CT causes significant variability in target contouring, resulting in incorrect dose calculations for organs of interest. CT-MR fusion-based approach has been advocated taking advantage of the complementary capabilities of CT (seed identification) and MRI (soft tissue visibility), and has proved to provide more accurate dosimetry calculations. However, seed segmentation in CT requires manual review, and the accuracy is limited by the reconstructed voxel resolution. In addition, CT deposits considerable amount of radiation to the patient. In this paper, we propose an X-ray and MRI based post-implant dosimetry approach. Implanted seeds are localized using three X-ray images by solving a combinatorial optimization problem, and the identified seeds are registered to MR images by an intensity-based points-to-volume registration. We pre-process the MR images using geometric and Gaussian filtering. To accommodate potential soft tissue deformation, our registration is performed in two steps, an initial affine transformation and local deformable registration. An evolutionary optimizer in conjunction with a points-to-volume similarity metric is used for the affine registration. Local prostate deformation and seed migration are then adjusted by the deformable registration step with external and internal force constraints. We tested our algorithm on six patient data sets, achieving registration error of (1.2+/-0.8) mm in < 30 sec. Our proposed approach has the potential to be a fast and cost-effective solution for post-implant dosimetry with equivalent accuracy as the CT-MR fusion-based approach.

A comparison of needle tip localization accuracy using 2D and 3D trans-rectal ultrasound for high-dose-rate prostate cancer brachytherapy treatment planning

NASA Astrophysics Data System (ADS)

Hrinivich, W. Thomas; Hoover, Douglas A.; Surry, Kathleen; Edirisinghe, Chandima; Montreuil, Jacques; D'Souza, David; Fenster, Aaron; Wong, Eugene

2016-03-01

Background: High-dose-rate brachytherapy (HDR-BT) is a prostate cancer treatment option involving the insertion of hollow needles into the gland through the perineum to deliver a radioactive source. Conventional needle imaging involves indexing a trans-rectal ultrasound (TRUS) probe in the superior/inferior (S/I) direction, using the axial transducer to produce an image set for organ segmentation. These images have limited resolution in the needle insertion direction (S/I), so the sagittal transducer is used to identify needle tips, requiring a manual registration with the axial view. This registration introduces a source of uncertainty in the final segmentations and subsequent treatment plan. Our lab has developed a device enabling 3D-TRUS guided insertions with high S/I spatial resolution, eliminating the need to align axial and sagittal views. Purpose: To compare HDR-BT needle tip localization accuracy between 2D and 3D-TRUS. Methods: 5 prostate cancer patients underwent conventional 2D TRUS guided HDR-BT, during which 3D images were also acquired for post-operative registration and segmentation. Needle end-length measurements were taken, providing a gold standard for insertion depths. Results: 73 needles were analyzed from all 5 patients. Needle tip position differences between imaging techniques was found to be largest in the S/I direction with mean+/-SD of -2.5+/-4.0 mm. End-length measurements indicated that 3D TRUS provided statistically significantly lower mean+/-SD insertion depth error of -0.2+/-3.4 mm versus 2.3+/-3.7 mm with 2D guidance (p < .001). Conclusions: 3D TRUS may provide more accurate HDR-BT needle localization than conventional 2D TRUS guidance for the majority of HDR-BT needles.

Cable attachment for a radioactive brachytherapy source capsule

DOEpatents

Gross, Ian G; Pierce, Larry A

2006-07-18

In cancer brachytherapy treatment, a small californium-252 neutron source capsule is attached to a guide cable using a modified crimping technique. The guide cable has a solid cylindrical end, and the attachment employs circumferential grooves micromachined in the solid cable end. The attachment was designed and tested, and hardware fabricated for use inside a radioactive hot cell. A welding step typically required in other cable attachments is avoided.

Targeting MRS-Defined Dominant Intraprostatic Lesions with Inverse-Planned High Dose Rate Brachytherapy

DTIC Science & Technology

2008-06-01

brachytherapy treatment planning has been demonstrated. Using the inverse planning program IPSA , dose escalation of target regions with a higher tumor...algorithm (called IPSA ) was used to generate dose distributions for five different levels of DIL- boost, at least 110%, 120%, 130%, 140% and 150...and LDR, VI Last Generation Radiotherapy Course, São Paulo, Brazil, Oct. 19, 2006. Principles and Clinical Applications of IPSA ; Nucletron

Dosimetric variations due to interfraction organ deformation in cervical cancer brachytherapy.

PubMed

Kobayashi, Kazuma; Murakami, Naoya; Wakita, Akihisa; Nakamura, Satoshi; Okamoto, Hiroyuki; Umezawa, Rei; Takahashi, Kana; Inaba, Koji; Igaki, Hiroshi; Ito, Yoshinori; Shigematsu, Naoyuki; Itami, Jun

2015-12-01

We quantitatively estimated dosimetric variations due to interfraction organ deformation in multi-fractionated high-dose-rate brachytherapy (HDRBT) for cervical cancer using a novel surface-based non-rigid deformable registration. As the number of consecutive HDRBT fractions increased, simple addition of dose-volume histogram parameters significantly overestimated the dose, compared with distribution-based dose addition. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Monte Carlo calculated doses to treatment volumes and organs at risk for permanent implant lung brachytherapy

NASA Astrophysics Data System (ADS)

Sutherland, J. G. H.; Furutani, K. M.; Thomson, R. M.

2013-10-01

Iodine-125 (125I) and Caesium-131 (131Cs) brachytherapy have been used with sublobar resection to treat stage I non-small cell lung cancer and other radionuclides, 169Yb and 103Pd, are considered for these treatments. This work investigates the dosimetry of permanent implant lung brachytherapy for a range of source energies and various implant sites in the lung. Monte Carlo calculated doses are calculated in a patient CT-derived computational phantom using the EGsnrc user-code BrachyDose. Calculations are performed for 103Pd, 125I, 131Cs seeds and 50 and 100 keV point sources for 17 implant positions. Doses to treatment volumes, ipsilateral lung, aorta, and heart are determined and compared to those determined using the TG-43 approach. Considerable variation with source energy and differences between model-based and TG-43 doses are found for both treatment volumes and organs. Doses to the heart and aorta generally increase with increasing source energy. TG-43 underestimates the dose to the heart and aorta for all implants except those nearest to these organs where the dose is overestimated. Results suggest that model-based dose calculations are crucial for selecting prescription doses, comparing clinical endpoints, and studying radiobiological effects for permanent implant lung brachytherapy.

Uveal Melanoma Regression after Brachytherapy: Relationship with Chromosome 3 Monosomy Status.

PubMed

Salvi, Sachin M; Aziz, Hassan A; Dar, Suhail; Singh, Nakul; Hayden-Loreck, Brandy; Singh, Arun D

2017-07-01

The objective was to evaluate the relationship between the regression rate of ciliary body melanoma and choroidal melanoma after brachytherapy and chromosome 3 monosomy status. We conducted a prospective and consecutive case series of patients who underwent biopsy and brachytherapy for ciliary/choroidal melanoma. Tumor biopsy performed at the time of radiation plaque placement was analyzed with fluorescence in situ hybridization to determine the percentage of tumor cells with chromosome 3 monosomy. The regression rate was calculated as the percent change in tumor height at months 3, 6, and 12. The relationship between regression rate and tumor location, initial tumor height, and chromosome 3 monosomy (percentage) was assessed by univariate linear regression (R version 3.1.0). Of the 75 patients included in the study, 8 had ciliary body melanoma, and 67 were choroidal melanomas. The mean tumor height at the time of diagnosis was 5.2 mm (range: 1.90-13.00). The percentage composition of chromosome 3 monosomy ranged from 0-20% (n = 35) to 81-100% (n = 40). The regression of tumor height at months 3, 6, and 12 did not statistically correlate with tumor location (ciliary or choroidal), initial tumor height, or chromosome 3 monosomy (percentage). The regression rate of choroidal melanoma following brachytherapy did not correlate with chromosome 3 monosomy status.

External radiotherapy and brachytherapy in the management of extrahepatic and intrahepatic cholangiocarcinoma: available evidence.

PubMed

Sahai, Puja; Kumar, Senthil

2017-08-01

This review aims to summarize the currently available evidence for the role of external radiotherapy and brachytherapy in the management of cholangiocarcinoma. High locoregional disease recurrence rates after surgical resection alone for both the extrahepatic cholangiocarcinoma (EHCC) and intrahepatic cholangiocarcinoma (IHCC) provide a rationale for using adjuvant radiotherapy with chemotherapy. We performed a literature search related to radiotherapy in cholangiocarcinoma published between 2000 and 2016. The role of radiation is discussed in the adjuvant, neoadjuvant, definitive and the palliative setting. Evidence from Phase II trials have demonstrated efficacy of adjuvant chemoradiation in combination with chemotherapy in EHCC. Locally advanced cholangiocarcinoma may be treated with neoadjuvant chemoradiotherapy. In the case of downsizing, assessment for resection may be considered. Brachytherapy offers dose escalation after external radiotherapy. Selected unresectable cases of cholangiocarcinoma may be considered for stereotactic body radiation therapy with neoadjuvant and/or concurrent chemotherapy. Liver transplantation is a treatment option in selected patients with EHCC and IHCC after neoadjuvant chemoradiation. Stenting in combination with palliative external radiotherapy and/or brachytherapy provides improved stent patency and survival. Newer advanced radiation techniques provide a scope for achieving better disease control with reduced morbidity. Effective multimodality treatment incorporating radiotherapy is the way forward for improving survival in patients with cholangiocarcinoma.

Dose rate calculations around 192Ir brachytherapy sources using a Sievert integration model

NASA Astrophysics Data System (ADS)

Karaiskos, P.; Angelopoulos, A.; Baras, P.; Rozaki-Mavrouli, H.; Sandilos, P.; Vlachos, L.; Sakelliou, L.

2000-02-01

The classical Sievert integral method is a valuable tool for dose rate calculations around brachytherapy sources, combining simplicity with reasonable computational times. However, its accuracy in predicting dose rate anisotropy around 192 Ir brachytherapy sources has been repeatedly put into question. In this work, we used a primary and scatter separation technique to improve an existing modification of the Sievert integral (Williamson's isotropic scatter model) that determines dose rate anisotropy around commercially available 192 Ir brachytherapy sources. The proposed Sievert formalism provides increased accuracy while maintaining the simplicity and computational time efficiency of the Sievert integral method. To describe transmission within the materials encountered, the formalism makes use of narrow beam attenuation coefficients which can be directly and easily calculated from the initially emitted 192 Ir spectrum. The other numerical parameters required for its implementation, once calculated with the aid of our home-made Monte Carlo simulation code, can be used for any 192 Ir source design. Calculations of dose rate and anisotropy functions with the proposed Sievert expression, around commonly used 192 Ir high dose rate sources and other 192 Ir elongated source designs, are in good agreement with corresponding accurate Monte Carlo results which have been reported by our group and other authors.

The Application of Elliptic Cylindrical Phantom in Brachytherapy Dosimetric Study of HDR 192Ir Source

NASA Astrophysics Data System (ADS)

Ahn, Woo Sang; Park, Sung Ho; Jung, Sang Hoon; Choi, Wonsik; Do Ahn, Seung; Shin, Seong Soo

2014-06-01

The purpose of this study is to determine the radial dose function of HDR 192Ir source based on Monte Carlo simulation using elliptic cylindrical phantom, similar to realistic shape of pelvis, in brachytherapy dosimetric study. The elliptic phantom size and shape was determined by analysis of dimensions of pelvis on CT images of 20 patients treated with brachytherapy for cervical cancer. The radial dose function obtained using the elliptic cylindrical water phantom was compared with radial dose functions for different spherical phantom sizes, including the Williamsion's data loaded into conventional planning system. The differences in the radial dose function for the different spherical water phantoms increase with radial distance, r, and the largest differences in the radial dose function appear for the smallest phantom size. The radial dose function of the elliptic cylindrical phantom significantly decreased with radial distance in the vertical direction due to different scatter condition in comparison with the Williamson's data. Considering doses to ICRU rectum and bladder points, doses to reference points can be underestimated up to 1-2% at the distance from 3 to 6 cm. The radial dose function in this study could be used as realistic data for calculating the brachytherapy dosimetry for cervical cancer.

Primary radiotherapy for carcinoma of the endometrium using external beam radiotherapy and single line source brachytherapy.

PubMed

Churn, M; Jones, B

1999-01-01

A small proportion of patients with adenocarcinoma of the endometrium are inoperable by virtue of severe concurrent medical conditions, gross obesity or advanced stage disease. They can be treated with primary radiotherapy with either curative or palliative intent. We report 37 such patients treated mainly with a combination of external beam radiotherapy and intracavitary brachytherapy using a single line source technique. The 5-year disease-specific survival for nonsurgically staged patients was 68.4% for FIGO Stages I and II and 33.3% for Stages III and IV. The incidence of late morbidity was acceptably low. Using the Franco-Italian Glossary, there was 27.0% grade 1 but no grade 2-4 bladder toxicity. For the rectum the rates were 18.9% grade 1, 5.4% grade 2, 2.7% grade 3, and no grade 4 toxicity. Methods of optimizing the dose distribution of the brachytherapy by means of variation of treatment length, radioactive source positions, and prescription point according to tumour bulk and individual anatomy are discussed. The biologically equivalent doses (BED) for combined external beam radiotherapy and brachytherapy were calculated to be in the range of 78-107 Gy(3) or 57-75 Gy(10) at point 'A' and appear adequate for the control of Stage I cancers.

Results of treatment of choroidal malignant melanoma with high-dose-rate strontium-90 brachytherapy. A retrospective study of 46 patients treated between 1983 and 1995.

PubMed

Missotten, L; Dirven, W; Van der Schueren, A; Leys, A; De Meester, G; Van Limbergen, E

1998-03-01

We review the results of treatment of small to medium-sized choroidal malignant melanomas after high-dose-rate brachytherapy with a strontium-90 applicator. The applicator is positioned against the sclera using an afterloading technique. Brachytherapy is completed in a single session lasting 2-4 h with the patient under local anaesthesia. From September 1983 until March 1995, 46 eyes were treated in this way. Most tumours were 7-11 mm in diameter (range from 4.5-15 mm) with a mean height of approximately 3 mm (range from 1.5-7 mm). Follow-up ranged from 6 months to 12 years (mean 49 months). Thirty of the 46 eyes had at the final evaluation a nonevolutive scar (20 of these after a single application, the others with some additional treatment). In 13 eyes the tumours were in involution but their complete destruction was not yet certain, and 3 eyes were enucleated for local recurrence. Three patients developed systemic metastases. No radiogenic complications were noticed. Strontium-90 brachytherapy is a valuable and safe treatment technique for small to medium-sized choroidal malignant melanomas. In addition the use of a strontium-90 applicator is inexpensive thanks to this element's long half-life and the short application time.

Information systems and human error in the lab.

PubMed

Bissell, Michael G

2004-01-01

Health system costs in clinical laboratories are incurred daily due to human error. Indeed, a major impetus for automating clinical laboratories has always been the opportunity it presents to simultaneously reduce cost and improve quality of operations by decreasing human error. But merely automating these processes is not enough. To the extent that introduction of these systems results in operators having less practice in dealing with unexpected events or becoming deskilled in problemsolving, however new kinds of error will likely appear. Clinical laboratories could potentially benefit by integrating findings on human error from modern behavioral science into their operations. Fully understanding human error requires a deep understanding of human information processing and cognition. Predicting and preventing negative consequences requires application of this understanding to laboratory operations. Although the occurrence of a particular error at a particular instant cannot be absolutely prevented, human error rates can be reduced. The following principles are key: an understanding of the process of learning in relation to error; understanding the origin of errors since this knowledge can be used to reduce their occurrence; optimal systems should be forgiving to the operator by absorbing errors, at least for a time; although much is known by industrial psychologists about how to write operating procedures and instructions in ways that reduce the probability of error, this expertise is hardly ever put to use in the laboratory; and a feedback mechanism must be designed into the system that enables the operator to recognize in real time that an error has occurred.

Key Performance Indicators in the Evaluation of the Quality of Radiation Safety Programs.

PubMed

Schultz, Cheryl Culver; Shaffer, Sheila; Fink-Bennett, Darlene; Winokur, Kay

2016-08-01

Beaumont is a multiple hospital health care system with a centralized radiation safety department. The health system operates under a broad scope Nuclear Regulatory Commission license but also maintains several other limited use NRC licenses in off-site facilities and clinics. The hospital-based program is expansive including diagnostic radiology and nuclear medicine (molecular imaging), interventional radiology, a comprehensive cardiovascular program, multiple forms of radiation therapy (low dose rate brachytherapy, high dose rate brachytherapy, external beam radiotherapy, and gamma knife), and the Research Institute (including basic bench top, human and animal). Each year, in the annual report, data is analyzed and then tracked and trended. While any summary report will, by nature, include items such as the number of pieces of equipment, inspections performed, staff monitored and educated and other similar parameters, not all include an objective review of the quality and effectiveness of the program. Through objective numerical data Beaumont adopted seven key performance indicators. The assertion made is that key performance indicators can be used to establish benchmarks for evaluation and comparison of the effectiveness and quality of radiation safety programs. Based on over a decade of data collection, and adoption of key performance indicators, this paper demonstrates one way to establish objective benchmarking for radiation safety programs in the health care environment.

Stochastic Models of Human Errors

NASA Technical Reports Server (NTRS)

Elshamy, Maged; Elliott, Dawn M. (Technical Monitor)

2002-01-01

Humans play an important role in the overall reliability of engineering systems. More often accidents and systems failure are traced to human errors. Therefore, in order to have meaningful system risk analysis, the reliability of the human element must be taken into consideration. Describing the human error process by mathematical models is a key to analyzing contributing factors. Therefore, the objective of this research effort is to establish stochastic models substantiated by sound theoretic foundation to address the occurrence of human errors in the processing of the space shuttle.

Operational Interventions to Maintenance Error

NASA Technical Reports Server (NTRS)

Kanki, Barbara G.; Walter, Diane; Dulchinos, VIcki

1997-01-01

A significant proportion of aviation accidents and incidents are known to be tied to human error. However, research of flight operational errors has shown that so-called pilot error often involves a variety of human factors issues and not a simple lack of individual technical skills. In aircraft maintenance operations, there is similar concern that maintenance errors which may lead to incidents and accidents are related to a large variety of human factors issues. Although maintenance error data and research are limited, industry initiatives involving human factors training in maintenance have become increasingly accepted as one type of maintenance error intervention. Conscientious efforts have been made in re-inventing the team7 concept for maintenance operations and in tailoring programs to fit the needs of technical opeRAtions. Nevertheless, there remains a dual challenge: 1) to develop human factors interventions which are directly supported by reliable human error data, and 2) to integrate human factors concepts into the procedures and practices of everyday technical tasks. In this paper, we describe several varieties of human factors interventions and focus on two specific alternatives which target problems related to procedures and practices; namely, 1) structured on-the-job training and 2) procedure re-design. We hope to demonstrate that the key to leveraging the impact of these solutions comes from focused interventions; that is, interventions which are derived from a clear understanding of specific maintenance errors, their operational context and human factors components.

Reduction of Maintenance Error Through Focused Interventions

NASA Technical Reports Server (NTRS)

Kanki, Barbara G.; Walter, Diane; Rosekind, Mark R. (Technical Monitor)

1997-01-01

It is well known that a significant proportion of aviation accidents and incidents are tied to human error. In flight operations, research of operational errors has shown that so-called "pilot error" often involves a variety of human factors issues and not a simple lack of individual technical skills. In aircraft maintenance operations, there is similar concern that maintenance errors which may lead to incidents and accidents are related to a large variety of human factors issues. Although maintenance error data and research are limited, industry initiatives involving human factors training in maintenance have become increasingly accepted as one type of maintenance error intervention. Conscientious efforts have been made in re-inventing the "team" concept for maintenance operations and in tailoring programs to fit the needs of technical operations. Nevertheless, there remains a dual challenge: to develop human factors interventions which are directly supported by reliable human error data, and to integrate human factors concepts into the procedures and practices of everyday technical tasks. In this paper, we describe several varieties of human factors interventions and focus on two specific alternatives which target problems related to procedures and practices; namely, 1) structured on-the-job training and 2) procedure re-design. We hope to demonstrate that the key to leveraging the impact of these solutions comes from focused interventions; that is, interventions which are derived from a clear understanding of specific maintenance errors, their operational context and human factors components.

New National Air-Kerma Standard for Low-Energy Electronic Brachytherapy Sources

PubMed Central

Seltzer, Stephen M; O’Brien, Michelle; Mitch, Michael G

2014-01-01

The new primary standard for low-energy electronic brachytherapy sources for the United States is described. These miniature x-ray tubes are inserted in catheters for interstitial radiation therapy and operate at tube potentials of up to about 50 kV. The standard is based on the realization of the air kerma produced by the x-ray beam at a reference distance in air of 50 cm. PMID:26601044

Development of a Pneumatic Robot for MRI-guided Transperineal Prostate Biopsy and Brachytherapy: New Approaches

PubMed Central

Song, Sang-Eun; Cho, Nathan B.; Fischer, Gregory; Hata, Nobuhito; Tempany, Clare; Fichtinger, Gabor; Iordachita, Iulian

2011-01-01

Magnetic Resonance Imaging (MRI) guided prostate biopsy and brachytherapy has been introduced in order to enhance the cancer detection and treatment. For the accurate needle positioning, a number of robotic assistants have been developed. However, problems exist due to the strong magnetic field and limited workspace. Pneumatically actuated robots have shown the minimum distraction in the environment but the confined workspace limits optimal robot design and thus controllability is often poor. To overcome the problem, a simple external damping mechanism using timing belts was sought and a 1-DOF mechanism test result indicated sufficient positioning accuracy. Based on the damping mechanism and modular system design approach, a new workspace-optimized 4-DOF parallel robot was developed for the MRI-guided prostate biopsy and brachytherapy. A preliminary evaluation of the robot was conducted using previously developed pneumatic controller and satisfying results were obtained. PMID:21399734

Dermo beta brachytherapy with 188-Re in squamous cell carcinoma of the penis: a new therapy.

PubMed

Carrozzo, Anna Maria; Sedda, Antioco Franco; Muscardin, Luca; Donati, Pietro; Cipriani, Cesidio

2013-04-01

Squamous cell carcinoma of the penis (SCCP) is the most common penis neoplasia, favoured by phimosis, HPV infection and scleroatrophic lichen. The classic therapy is surgical with anatomic demolition, which often causes important psychological problems. Other non-demolitive therapies can be utilized, such as radiotherapy, brachytherapy and topical medical treatment. We propose a new non-invasive therapy called "Dermo beta brachytherapy (DBBT) with 188-Re" in which a synthetic inert resin-matrix containing a radioactive beta-emitting isotope is applied on the surface of the tumor lesion. A total of 15 patients with a histologically confirmed diagnosis of SCCP were enrolled for treatment (DBBT). Of the 15 patients, 12 healed, 1 was lost at follow-up and 2 did not respond to therapy. The results indicate that DBBT is an effective treatment for SCC of the penis, sparing the anatomical integrity of the organ, and allowing normal sexual activity.

Automated seed localization from CT datasets of the prostate.

PubMed

Brinkmann, D H; Kline, R W

1998-09-01

With the increasing utilization of permanent brachytherapy implants for treating carcinoma of the prostate, the importance of accurate post-treatment dose calculation also increases for assessing patient outcome and planning future treatments. An automatic method for seed localization of permanent brachytherapy implants, using CT datasets of the prostate, has been developed and tested on a phantom using an actual patient planned seed distribution. This method was also compared to results with the three-film technique for three patient datasets. The automatic method is as accurate or more accurate than the three film technique for 1 mm, 3 mm, and 5 mm contiguous CT slices, and eliminates the inter- and intra-observer variability of the manual methods. The automated method improves the localization of brachytherapy seeds while reducing the time required for the user to input information, and is demonstrated to be less operator dependent, less time consuming, and potentially more accurate than the three-film technique.

Complications associated with brachytherapy alone or with laser in lung cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khanavkar, B.; Stern, P.; Alberti, W.

1991-05-01

Relatively little has been reported about destruction through brachytherapy of mucosa-perforating and extraluminary tumors with probable large vessel involvement causing major hemorrhagic or fistular complications. We report 12 patients subjected to laser and brachytherapy for centrally occluding lung cancer, whom we have periodically followed up from June 1986 until they died. Although all laser procedures were free from complications, necrotic cavitation in five cases, two of which were accompanied by large bronchoesophageal fistulas, and massive fatal hemoptysis occurred in six. Minor complications included radiation mucositis (two), noncritical mucosal scarring (two), and cough (four). Characteristics that will identify patients at riskmore » of developing fatal hemoptysis and fistulas should be better defined by imaging and endoscopic techniques. In such cases, modifying the protocol or using alternative procedures should be considered. Minor complications, such as cough, can be avoided by using topical steroid therapy (eg, beclomethasone dipropionate).« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rivard, M.

With the recent introduction of heterogeneity correction algorithms for brachytherapy, the AAPM community is still unclear on how to commission and implement these into clinical practice. The recently-published AAPM TG-186 report discusses important issues for clinical implementation of these algorithms. A charge of the AAPM-ESTRO-ABG Working Group on MBDCA in Brachytherapy (WGMBDCA) is the development of a set of well-defined test case plans, available as references in the software commissioning process to be performed by clinical end-users. In this practical medical physics course, specific examples on how to perform the commissioning process are presented, as well as descriptions of themore » clinical impact from recent literature reporting comparisons of TG-43 and heterogeneity-based dosimetry. Learning Objectives: Identify key clinical applications needing advanced dose calculation in brachytherapy. Review TG-186 and WGMBDCA guidelines, commission process, and dosimetry benchmarks. Evaluate clinical cases using commercially available systems and compare to TG-43 dosimetry.« less