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Sample records for radiotherapy system efarad

  1. Radiotherapy dosimetry using a commercial OSL system

    SciTech Connect

    Viamonte, A.; Rosa, L. A. R. da; Buckley, L. A.; Cherpak, A.; Cygler, J. E.

    2008-04-15

    A commercial optically stimulated luminescence (OSL) system developed for radiation protection dosimetry by Landauer, Inc., the InLight microStar reader, was tested for dosimetry procedures in radiotherapy. The system uses carbon-doped aluminum oxide, Al{sub 2}O{sub 3}:C, as a radiation detector material. Using this OSL system, a percent depth dose curve for {sup 60}Co gamma radiation was measured in solid water. Field size and SSD dependences of the detector response were also evaluated. The dose response relationship was investigated between 25 and 400 cGy. The decay of the response with time following irradiation and the energy dependence of the Al{sub 2}O{sub 3}:C OSL detectors were also measured. The results obtained using OSL dosimeters show good agreement with ionization chamber and diode measurements carried out under the same conditions. Reproducibility studies show that the response of the OSL system to repeated exposures is 2.5% (1sd), indicating a real possibility of applying the Landauer OSL commercial system for radiotherapy dosimetric procedures.

  2. Dosimetry audit of radiotherapy treatment planning systems.

    PubMed

    Bulski, Wojciech; Chełmiński, Krzysztof; Rostkowska, Joanna

    2015-07-01

    In radiotherapy Treatment Planning Systems (TPS) various calculation algorithms are used. The accuracy of dose calculations has to be verified. Numerous phantom types, detectors and measurement methodologies are proposed to verify the TPS calculations with dosimetric measurements. A heterogeneous slab phantom has been designed within a Coordinated Research Project (CRP) of the IAEA. The heterogeneous phantom was developed in the frame of the IAEA CRP. The phantom consists of frame slabs made with polystyrene and exchangeable inhomogeneity slabs equivalent to bone or lung tissue. Special inserts allow to position thermoluminescent dosimeters (TLD) capsules within the polystyrene slabs below the bone or lung equivalent slabs and also within the lung equivalent material. Additionally, there are inserts that allow to position films or ionisation chamber in the phantom. Ten Polish radiotherapy centres (of 30 in total) were audited during on-site visits. Six different TPSs and five calculation algorithms were examined in the presence of inhomogeneities. Generally, most of the results from TLD were within 5 % tolerance. Differences between doses calculated by TPSs and measured with TLD did not exceed 4 % for bone and polystyrene equivalent materials. Under the lung equivalent material, on the beam axis the differences were lower than 5 %, whereas inside the lung equivalent material, off the beam axis, in some cases they were of around 7 %. The TLD results were confirmed with the ionisation chamber measurements. The comparison results of the calculations and the measurements allow to detect limitations of TPS calculation algorithms. The audits performed with the use of heterogeneous phantom and TLD seem to be an effective tool for detecting the limitations in the TPS performance or beam configuration errors at audited radiotherapy departments.

  3. System Toward Automation in Radiotherapy Treatment: START

    NASA Astrophysics Data System (ADS)

    Cheng, Andrew Y. S.; Tsoi, Kenneth Y. P.

    1994-10-01

    START is a new automation system invented for nasopharyngeal carcinoma treatment. A laser scanner system capable of non-contact digitization of 3D surface is used to digitize the contours of the patient's face, shoulder and special landmark reference features of the patient. These features are stored in the computer in 3D digitized format. The digitized facial features with traced landmark reference features are used for fabrication of a true sized wood-particle laminates mould by a computer numerical controlled milling system. A Cobex mask is formed on this mould by using vacuum forming technique. With an image analysis and computer aided design system, the X-ray film with treatment window marked is traced automatically and converted to match the prescanned 3D information. A computer controlled 6-axis robot can precisely mark out the required areas on the Cobex cast for treatment. Finally, the patient receives radiotherapy treatment with the Cobex case as a positioning registration device. The new system will replace the manual procedure with better patient comfort, higher efficiency and enhanced accuracy.

  4. [Prostate localization systems for prostate radiotherapy].

    PubMed

    de Crevoisier, R; Lagrange, J-L; Messai, T; M'Barek, B; Lefkopoulos, D

    2006-11-01

    The development of sophisticated conformal radiation therapy techniques for prostate cancer, such as intensity-modulated radiotherapy, implies precise and accurate targeting. Inter- and intrafraction prostate motion can be significant and should be characterized, unless the target volume may occasionally be missed. Indeed, bony landmark-based portal imaging does not provide the positional information for soft-tissue targets (prostate and seminal vesicles) or critical organs (rectum and bladder). In this article, we describe various prostate localization systems used before or during the fraction: rectal balloon, intraprostatic fiducials, ultrasound-based localization, integrated CT/linear accelerator system, megavoltage or kilovoltage cone-beam CT, Calypso 4D localization system tomotherapy, Cyberknife and Exactrac X-Ray 6D. The clinical benefit in using such prostate localization tools is not proven by randomized studies and the feasibility has just been established for some of these techniques. Nevertheless, these systems should improve local control by a more accurate delivery of an increased prescribed dose in a reduced planning target volume.

  5. Palliative radiotherapy practice within Western European countries: impact of the radiotherapy financing system?

    PubMed

    Lievens, Y; Van den Bogaert, W; Rijnders, A; Kutcher, G; Kesteloot, K

    2000-09-01

    To analyze the reimbursement modalities for radiotherapy in the different Western European countries, as well as to investigate if these differences have an impact on the palliative radiotherapy practice for bone metastases. A questionnaire was sent to 565 radiotherapy centres included in the 1997 ESTRO directory. In this questionnaire the reimbursement strategy applied in the different centres was assessed, with respect to the use of a budget (departmental or hospital budget), case payment and/or fee-for-service reimbursement. The differences were analyzed according to country and to type and size of the radiotherapy centre. A total of 170 centres (86% of the responders) returned the questionnaire. Most frequent is budget reimbursement: some form of budget reimbursement is found in 69% of the centres, whereas 46% of the centres are partly reimbursed through fee-for-service and 35% through case payment. The larger the department, the more frequent the reimbursement through a budget or a case payment system and the less the importance of fee-for-service reimbursement (chi(2): P=0.0012; logit: P=0.0055). Whereas private centres are almost equally reimbursed by fee-for-service financing as by budget or case payment, radiotherapy departments in university hospitals receive the largest part of their financial resources through a budget or by case payment (83%) (chi(2): P=0.002; logit: P=0.0073). A correlation between the country and the radiotherapy reimbursement system was also demonstrated (P=0.002), radiotherapy centres in Spain, the Netherlands and the United Kingdom being almost entirely reimbursed through a budget and/or case payment and centres in Germany and Switzerland mostly through a fee-for-service system. In budget and case payment financing lower total number of fractions and lower total dose (chi(2): P=0.003; logit: P=0.0120) as well as less shielding blocks (chi(2): P=0.003; logit: P=0.0066) are used. A same tendency is found for the use of isodose

  6. An electromechanical, patient positioning system for head and neck radiotherapy.

    PubMed

    Ostyn, Mark; Dwyer, Thomas; Miller, Matthew; King, Paden; Sacks, Rachel; Cruikshank, Ross; Rosario, Melvin; Martinez, Daniel; Kim, Siyong; Yeo, Woon-Hong

    2017-09-05

    In cancer treatment with radiation, accurate patient setup is critical for proper dose delivery. Improper arrangement can lead to disease recurrence, permanent organ damage, or lack of disease control. While current immobilization equipment often helps for patient positioning, manual adjustment is required, involving iterative, time-consuming steps. Here, we present an electromechanical robotic system for improving patient setup in radiotherapy, specifically targeting head and neck cancer. This positioning system offers six degrees of freedom for a variety of applications in radiation oncology. An analytical calculation of inverse kinematics serves as fundamental criteria to design the system. Computational mechanical modeling and experimental study of radiotherapy compatibility and x-ray-based imaging demonstrates the device feasibility and reliability to be used in radiotherapy. An absolute positioning accuracy test in a clinical treatment room supports the clinical feasibility of the system.

  7. An electromechanical, patient positioning system for head and neck radiotherapy

    NASA Astrophysics Data System (ADS)

    Ostyn, Mark; Dwyer, Thomas; Miller, Matthew; King, Paden; Sacks, Rachel; Cruikshank, Ross; Rosario, Melvin; Martinez, Daniel; Kim, Siyong; Yeo, Woon-Hong

    2017-09-01

    In cancer treatment with radiation, accurate patient setup is critical for proper dose delivery. Improper arrangement can lead to disease recurrence, permanent organ damage, or lack of disease control. While current immobilization equipment often helps for patient positioning, manual adjustment is required, involving iterative, time-consuming steps. Here, we present an electromechanical robotic system for improving patient setup in radiotherapy, specifically targeting head and neck cancer. This positioning system offers six degrees of freedom for a variety of applications in radiation oncology. An analytical calculation of inverse kinematics serves as fundamental criteria to design the system. Computational mechanical modeling and experimental study of radiotherapy compatibility and x-ray-based imaging demonstrates the device feasibility and reliability to be used in radiotherapy. An absolute positioning accuracy test in a clinical treatment room supports the clinical feasibility of the system.

  8. [Implementation of "never events" checklists in a radiotherapy information system].

    PubMed

    Brusadin, G; Bour, M S; Deutsch, E; Kouchit, N; Corbin, S; Lefkopoulos, D

    2017-08-18

    In order to reduce the incidence of major accidents during external radiotherapy treatment, "never events" checklists have been incorporated into the "record and verify" system. This article details this process. Prospects for improvement are also proposed, including a peer-to-peer audit on the use of checklists and the availability of the radiotherapy information system manufacturer to collaborate in this process to secure the patients' journey. Copyright © 2017 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  9. Dosimetry audit simulation of treatment planning system in multicenters radiotherapy

    NASA Astrophysics Data System (ADS)

    Kasmuri, S.; Pawiro, S. A.

    2017-07-01

    Treatment Planning System (TPS) is an important modality that determines radiotherapy outcome. TPS requires input data obtained through commissioning and the potentially error occurred. Error in this stage may result in the systematic error. The aim of this study to verify the TPS dosimetry to know deviation range between calculated and measurement dose. This study used CIRS phantom 002LFC representing the human thorax and simulated all external beam radiotherapy stages. The phantom was scanned using CT Scanner and planned 8 test cases that were similar to those in clinical practice situation were made, tested in four radiotherapy centers. Dose measurement using 0.6 cc ionization chamber. The results of this study showed that generally, deviation of all test cases in four centers was within agreement criteria with average deviation about -0.17±1.59 %, -1.64±1.92 %, 0.34±1.34 % and 0.13±1.81 %. The conclusion of this study was all TPS involved in this study showed good performance. The superposition algorithm showed rather poor performance than either analytic anisotropic algorithm (AAA) and convolution algorithm with average deviation about -1.64±1.92 %, -0.17±1.59 % and -0.27±1.51 % respectively.

  10. [Innovation and the next generation radiotherapy system].

    PubMed

    Tanabe, Eiji

    2013-01-01

    Innovation is the key to future success for Japan that is slowly falling behind. Industries targeted by the "Abenomics" growth strategy include healthcare and medicine. Since cancer is the leading cause of death in Japan, the development of a system that can detect and treat early stage cancers will be very valuable for patient QOL and reducing health care costs. Although the effectiveness of radiation therapy for treating early stage cancer is widely recognized, there has been no system to treat small, moving tumors with sub millimeter accuracy. A project supported by NEDO develops a "Next-Generation Radiation Therapy System" that uses high energy, narrow X-rays beams that can be accurately pinpointed deep inside the body. Performance testing of a prototype system is currently underway at the National Center for Global Health and Medicine in Tokyo.

  11. An optical system for measuring surface shapes for radiotherapy planning.

    PubMed

    Wilks, R J

    1993-04-01

    A system which uses two remote cameras to obtain surface contours for radiotherapy patients is described. Two variants are presented: one which requires couch movement to obtain multiple outlines, and one utilizing a special illumination method to achieve multiple outlines from one image per camera. In addition, a technique is discussed in which the grey-scale information from the skin surface (e.g., skin marks placed by the radiotherapist) may be utilized in displaying three-dimensional surface information. The system may also be used to monitor patient position in real time during each treatment.

  12. Systemic radiotherapy--the new frontier

    SciTech Connect

    Order, S.E. )

    1990-05-01

    The present day use of systemically administered isotopes and conjugated isotopic combinations are reviewed. Administration of 131Iodine in thyroid cancer led to a 97% local control and 50% complete remission of pulmonary metastases. Specificity directed isotopic therapy (metabolic, hormonal, and antibody) is discussed and includes factors such as tumor physiology and isotopic linkage. The clinical results and new knowledge being gained in Hodgkin's disease, non-Hodgkin's, colorectal, hepatoma, intrahepatic biliary and gliomatous cancers are reviewed. The dose response relationship to tumor remission is demonstrated in Hodgkin's treated with 131I antiferritin (40% partial remission) and more recently 90Yttrium antiferritin (50% complete response). Varied routes of administration, the problem of anti-antibody and bone marrow transplantation are discussed. Finally, the challenge to radiobiologists, physicists, chemists, immunologists, nuclear radiologists, and radiation oncologists is emphasized by definition of the new laboratory and clinical approaches being developed in systemic radiation therapy. 81 references.

  13. Cancer Deaths due to Lack of Universal Access to Radiotherapy in the Brazilian Public Health System.

    PubMed

    Mendez, L C; Moraes, F Y; Fernandes, G Dos S; Weltman, E

    2017-10-05

    Radiotherapy plays a fundamental role in the treatment of cancer. Currently, the Brazilian public health system cannot match the national radiotherapy demand and many patients requiring radiotherapy are never exposed to this treatment. This study estimated the number of preventable deaths in the public health system if access to radiotherapy was universal. Incidence rates for the year 2016 provided by Instituto Nacional de Cancer were used in this analysis. The number of untreated patients requiring radiotherapy was obtained through the difference between the total number of patients requiring radiotherapy and the total amount of delivered radiotherapy treatments in the public health system. The number of deaths for the three most common cancers in each gender due to radiotherapy shortage was calculated. Initially, the total number of patients per cancer type was divided in stages using Brazilian epidemiological data. Subsequently, previously published tree arm diagrams were used to define the rate of patients requiring radiotherapy in each specific clinical setting. Finally, the clinical benefit of radiotherapy in overall survival was extracted from studies with level 1 evidence. Over 596 000 cancer cases were expected in Brazil in 2016. The public health system covers more than 75% of the Brazilian population and an estimated 111 432 patients who required radiotherapy in 2016 did not receive this treatment. Breast, colorectal and cervix cancers are the most frequent malignant tumours in women and prostate, lung and colorectal in men. The number of deaths due to a radiotherapy shortage in the year 2016 for these types of cancer were: (i) breast: 1011 deaths in 10 years; (ii) cervix: 2006 deaths in 2 years; (iii) lung: 1206 deaths in 2 years; (iv) prostate, intermediate risk: 562 deaths in 13 years; high risk: 298 deaths in 10 years; (v) colorectal: 0 deaths, as radiotherapy has no proven benefit in overall survival. Thousands of cancer patients requiring

  14. A quality assurance system based on ISO standards: experience in a radiotherapy department.

    PubMed

    Leer, J W; Corver, R; Kraus, J J; vd Togt, J C; Buruma, O J

    1995-04-01

    The European radiotherapy society has for many years had a great interest in quality assurance. The EORTC radiotherapy group has put enormous effort into its quality assurance programmes. However, besides programmes for dosimetry and guide-lines for infrastructure, the organisation of a department should also be subject to a quality assurance system. In 1992, in the radiotherapy department in Leiden, a project was started to develop a quality assurance system based on the so-called ISO 9001 quality standards. This paper describes how these standards can be applied to create a quality assurance system in a hospital department.

  15. An image guided small animal stereotactic radiotherapy system

    PubMed Central

    Sha, Hao; Udayakumar, Thirupandiyur S.; Johnson, Perry B.; Dogan, Nesrin; Pollack, Alan; Yang, Yidong

    2016-01-01

    Small animal radiotherapy studies should be performed preferably on irradiators capable of focal tumor irradiation and healthy tissue sparing. In this study, an image guided small animal arc radiation treatment system (iSMAART) was developed which can achieve highly precise radiation targeting through the utilization of onboard cone beam computed tomography (CBCT) guidance. The iSMAART employs a unique imaging and radiation geometry where animals are positioned upright. It consists of a stationary x-ray tube, a stationary flat panel detector, and a rotatable and translational animal stage. System performance was evaluated in regards to imaging, image guidance, animal positioning, and radiation targeting using phantoms and tumor bearing animals. The onboard CBCT achieved good signal, contrast, and sub-millimeter spatial resolution. The iodine contrast CBCT accurately delineated orthotopic prostate tumors. Animal positioning was evaluated with ∼0.3 mm vertical displacement along superior-inferior direction. The overall targeting precision was within 0.4 mm. Stereotactic radiation beams conformal to tumor targets can be precisely delivered from multiple angles surrounding the animal. The iSMAART allows radiobiology labs to utilize an image guided precision radiation technique that can focally irradiate tumors while sparing healthy tissues at an affordable cost. PMID:26958942

  16. [Audits of the quality management system and safety in radiotherapy: Lessons learned and future prospects].

    PubMed

    Leroy, E; Marque, A

    2016-10-01

    The external audit of the management system of quality and safety in radiotherapy by quality managers of the French Association of Quality and Safety in Radiotherapy (AFQSR) is an opportunity to exchange good practices, returns of experience, effectiveness and weaknesses of the quality system, and its perceptions by all the teams. We present the results of the first audits conducted, and the results of a survey on the perception of quality at national level. Copyright © 2016. Published by Elsevier SAS.

  17. Risk factors for radiotherapy incidents and impact of an online electronic reporting system.

    PubMed

    Chang, David W; Cheetham, Lynn; te Marvelde, Luc; Bressel, Mathias; Kron, Tomas; Gill, Suki; Tai, Keen Hun; Ball, David; Rose, William; Silva, Linas; Foroudi, Farshad

    2014-08-01

    To ascertain the rate, type, significance, trends and the potential risk factors associated with radiotherapy incidents in a large academic department. Data for all radiotherapy activities from July 2001 to January 2011 were reviewed from radiotherapy incident reporting forms. Patient and treatment data were obtained from the radiotherapy record and verification database (MOSAIQ) and the patient database (HOSPRO). Logistic regression analyses were performed to determine variables associated with radiotherapy incidents. In that time, 65,376 courses of radiotherapy were delivered with a reported incident rate of 2.64 per 100 courses. The rate of incidents per course increased (1.96 per 100 courses to 3.52 per 100 courses, p<0.001) whereas the proportion of reported incidents resulting in >5% deviation in dose (10.50 to 2.75%, p<0.001) had decreased after the introduction of an online electronic reporting system. The following variables were associated with an increased rate of incidents: afternoon treatment time, paediatric patients, males, inpatients, palliative plans, head-and-neck, skin, sarcoma and haematological malignancies. In general, complex plans were associated with higher incidence rates. Radiotherapy incidents were infrequent and most did not result in significant dose deviation. A number of risk factors were identified and these could be used to highlight high-risk cases in the future. Introduction of an online electronic reporting system resulted in a significant increase in the number of incidents being reported. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. Effect of radiotherapy on the microleakage of adhesive systems.

    PubMed

    Bulucu, Bilinç; Avsar, Aysun; Demiryürek, Ebru Ozsezer; Yesilyurt, Cemal

    2009-08-01

    The aim of this in vitro study was to evaluate the effect of radiotherapy on the microleakage of three adhesive systems: a one-step self-etching, a two-step self-etching, and an etch-and-rinse system. Box-shaped Class V cavity preparations were prepared on the buccal surfaces of 84 extracted human molars. The molars were randomly assigned into 6 groups (n = 14) according to the irradiation and adhesive system as follows: G1, Clearfil S3 Bond (irradiated); G2, Clearfil SE Bond (irradiated); G3, Prime & Bond NT (irradiated); G4, Clearfil S3 Bond (nonirradiated); G5, Clearfil SE Bond (nonirradiated); and G6, Prime & Bond NT (nonirradiated). The cavities were restored with composite resin (Filtek Z 250). After restoration of the samples, a total dose of 60 Gy was delivered in 2 Gy/d fractions for 5 days per week for 6 weeks for the related groups. All specimens were thermocycled for 200 cycles between 5 degrees C and 55 degrees C using a dwell time of 60 s in each bath and then placed in 0.5% basic fuchsin solution for 24 h at room temperature. Specimens were then rinsed and sectioned; the dye penetration at the enamel and dentin margins was examined using a stereomicroscope, and a score of 0 to 3 was assigned. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U-tests. No statistically significant difference existed between the irradiated and nonirradiated groups (p > 0.05). Significant differences in microleakage were observed between enamel and dentin (p < 0.01). The microleakage at the dentin margins was greater than at the enamel margins. Prime & Bond NT revealed statistically significantly (p < 0.05) higher leakage scores in dentin than did ClearfilS3 Bond and Clearfil SE Bond. Within the limitations of this study, irradiation application did not affect the microleakage of dental adhesive systems.

  19. Human mesenchymal stem cells enhance the systemic effects of radiotherapy.

    PubMed

    de Araújo Farias, Virgínea; O'Valle, Francisco; Lerma, Borja Alonso; Ruiz de Almodóvar, Carmen; López-Peñalver, Jesús J; Nieto, Ana; Santos, Ana; Fernández, Beatriz Irene; Guerra-Librero, Ana; Ruiz-Ruiz, María Carmen; Guirado, Damián; Schmidt, Thomas; Oliver, Francisco Javier; Ruiz de Almodóvar, José Mariano

    2015-10-13

    The outcome of radiotherapy treatment might be further improved by a better understanding of individual variations in tumor radiosensitivity and normal tissue reactions, including the bystander effect. For many tumors, however, a definitive cure cannot be achieved, despite the availablity of more and more effective cancer treatments. Therefore, any improvement in the efficacy of radiotherapy will undoubtedly benefit a significant number of patients. Many experimental studies measure a bystander component of tumor cell death after radiotherapy, which highlights the importance of confirming these observations in a preclinical situation. Mesenchymal stem cells (MSCs) have been investigated for use in the treatment of cancers as they are able to both preferentially home onto tumors and become incorporated into their stroma. This process increases after radiation therapy. In our study we show that in vitro MSCs, when activated with a low dose of radiation, are a source of anti-tumor cytokines that decrease the proliferative activity of tumor cells, producing a potent cytotoxic synergistic effect on tumor cells. In vivo administration of unirradiated mesenchymal cells together with radiation leads to an increased efficacy of radiotherapy, thus leading to an enhancement of short and long range bystander effects on primary-irradiated tumors and distant-non-irradiated tumors. Our experiments indicate an increased cell loss rate and the decrease in the tumor cell proliferation activity as the major mechanisms underlying the delayed tumor growth and are a strong indicator of the synergistic effect between RT and MSC when they are applied together for tumor treatment in this model.

  20. Human mesenchymal stem cells enhance the systemic effects of radiotherapy

    PubMed Central

    de Araújo Farias, Virgínea; O'Valle, Francisco; Lerma, Borja Alonso; Ruiz de Almodóvar, Carmen; López-Peñalver, Jesús J.; Nieto, Ana; Santos, Ana; Fernández, Beatriz Irene; Guerra-Librero, Ana; Ruiz-Ruiz, María Carmen; Guirado, Damián; Schmidt, Thomas; Oliver, Francisco Javier; Ruiz de Almodóvar, José Mariano

    2015-01-01

    The outcome of radiotherapy treatment might be further improved by a better understanding of individual variations in tumor radiosensitivity and normal tissue reactions, including the bystander effect. For many tumors, however, a definitive cure cannot be achieved, despite the availablity of more and more effective cancer treatments. Therefore, any improvement in the efficacy of radiotherapy will undoubtedly benefit a significant number of patients. Many experimental studies measure a bystander component of tumor cell death after radiotherapy, which highlights the importance of confirming these observations in a preclinical situation. Mesenchymal stem cells (MSCs) have been investigated for use in the treatment of cancers as they are able to both preferentially home onto tumors and become incorporated into their stroma. This process increases after radiation therapy. In our study we show that in vitro MSCs, when activated with a low dose of radiation, are a source of anti-tumor cytokines that decrease the proliferative activity of tumor cells, producing a potent cytotoxic synergistic effect on tumor cells. In vivo administration of unirradiated mesenchymal cells together with radiation leads to an increased efficacy of radiotherapy, thus leading to an enhancement of short and long range bystander effects on primary-irradiated tumors and distant-non-irradiated tumors. Our experiments indicate an increased cell loss rate and the decrease in the tumor cell proliferation activity as the major mechanisms underlying the delayed tumor growth and are a strong indicator of the synergistic effect between RT and MSC when they are applied together for tumor treatment in this model. PMID:26378036

  1. Stereotactic Radiotherapy of Central Nervous System and Head and Neck Lesions, Using a Conformal Intensity-Modulated Radiotherapy System (Peacock™ System)

    PubMed Central

    Ammirati, Mario; Bernardo, Antonio; Ramsinghani, Nilam; Yakoob, Richard; Al-Ghazi, Matthew; Kuo, Jeffrey; Ammirati, Giuseppe

    2001-01-01

    The objective of this article is to evaluate single-fraction or fractionated stereotactic radiotherapy of central nervous system (CNS) and head and neck lesions using intensity-modulated radiotherapy (IMRT) with a commercially available system (Peacock™, Nomos Corporation, Sewickley, PA). This system allows tomotherapeutic delivery of intensity-modulated radiation, that is, the slice-by-slice treatment of the volume of interest with an intensity-modulated beam, making the delivery of highly conformal radiation to the target possible in both single or multiple fractions mode. During an 18-month period, 43 (21 males and 22 females) patients were treated, using a removable cranial screw-fixation device. Ages ranged from 10 to 77 years (mean, 52.2; median, 53.5). Intra- and extra-axial lesions, including head and neck malignancies and spine metastases, were treated. Clinical target volume ranged from 0.77 to 195 cm3 (mean, 47.8; median, 29.90). The dose distribution was normalized to the maximum and was prescribed, in most cases, at the 80% or 90% isodose line (range, 65 to 96%; median, 85%; mean, 83.4%) and ranged from 14 to 80 Gy (mean, 48; median, 50). The number of fractions ranged from 1 to 40 (mean, 23; median, 25). In all but one patient, 90% of the prescription isodose line covered 100% of the clinical target volume. The heterogeneity index (the ratio between the maximum radiation dose and the prescribed dose) ranged between 1.0 and 1.50, whereas the conformity index (the ratio between the volume encompassed by the prescription isodose line and the clinical target volume) ranged between 1.0 and 4.5. There were no complications related to the radiation treatment. With a median follow-up of 6 months, more than 70% of our patients showed decreased lesion size. Stereotactic IMRT of CNS and head and neck lesions can be delivered safely and accurately. The Peacock system delivers stereotactic radiation in single or multiple fractions and has no volume limitations

  2. [Development of quality assurance/quality control web system in radiotherapy].

    PubMed

    Okamoto, Hiroyuki; Mochizuki, Toshihiko; Yokoyama, Kazutoshi; Wakita, Akihisa; Nakamura, Satoshi; Ueki, Heihachi; Shiozawa, Keiko; Sasaki, Koji; Fuse, Masashi; Abe, Yoshihisa; Itami, Jun

    2013-12-01

    Our purpose is to develop a QA/QC (quality assurance/quality control) web system using a server-side script language such as HTML (HyperText Markup Language) and PHP (Hypertext Preprocessor), which can be useful as a tool to share information about QA/QC in radiotherapy. The system proposed in this study can be easily built in one's own institute, because HTML can be easily handled. There are two desired functions in a QA/QC web system: (i) To review the results of QA/QC for a radiotherapy machine, manuals, and reports necessary for routinely performing radiotherapy through this system. By disclosing the results, transparency can be maintained, (ii) To reveal a protocol for QA/QC in one's own institute using pictures and movies relating to QA/QC for simplicity's sake, which can also be used as an educational tool for junior radiation technologists and medical physicists. By using this system, not only administrators, but also all staff involved in radiotherapy, can obtain information about the conditions and accuracy of treatment machines through the QA/QC web system.

  3. Quality management system in radiotherapy in the light of regulations applicable in Poland.

    PubMed

    Bogusz-Czerniewicz, Marta

    2012-01-01

    The need to establish conditions for safe irradiation was noted in Poland back in 1986 in the Atomic Law, but for over 16 years no regulations regarding this aspect were passed. The radiological incident in Bialystok (Poland) in 2001 undeniably accelerated the implementation of new legal regulations. Nevertheless, in the absence of national guidelines until 2002, most health care institutions resorted to the quality management system (QMS) model proposed by the ISO norm 9001:2000. Eventually, practice proved the theory and the aforementioned model was also implemented into Polish acts of law defining basic requirements for QMS in radiotherapy. The aim of this work is to review current national regulations regarding QMS in radiotherapy, in particular those referring to standard procedures, the establishment of a commission for procedures and performance of external and internal clinical audits in oncological radiotherapy, as well as to present the process of their implementation into the practice of health care institutions.

  4. Quality management system in radiotherapy in the light of regulations applicable in Poland

    PubMed Central

    2012-01-01

    The need to establish conditions for safe irradiation was noted in Poland back in 1986 in the Atomic Law, but for over 16 years no regulations regarding this aspect were passed. The radiological incident in Bialystok (Poland) in 2001 undeniably accelerated the implementation of new legal regulations. Nevertheless, in the absence of national guidelines until 2002, most health care institutions resorted to the quality management system (QMS) model proposed by the ISO norm 9001:2000. Eventually, practice proved the theory and the aforementioned model was also implemented into Polish acts of law defining basic requirements for QMS in radiotherapy. The aim of this work is to review current national regulations regarding QMS in radiotherapy, in particular those referring to standard procedures, the establishment of a commission for procedures and performance of external and internal clinical audits in oncological radiotherapy, as well as to present the process of their implementation into the practice of health care institutions. PMID:23788867

  5. Radiotherapy in the treatment of primary central nervous system lymphoma (PCNSL).

    PubMed

    Nelson, D F

    1999-07-01

    The use of radiotherapy alone to treat primary central nervous system lymphoma (PCNSL) does not produce the high local control and survival rates that it does in limited extranodal non-Hodgkin's lymphoma outside the central nervous system (CNS). Even with doses of whole brain radiation therapy (WBRT) to 40+20 Gy boost, the Radiation Therapy Oncology Group (RTOG) reported a local control rate of 39%. Seventy-nine percent of recurrences were in the 60 Gy region. The median survival was 11.6 months. This response to local radiotherapy is quite different from the response of non-CNS Diffuse Large Cell Lymphoma where doses of 30-40 and >40 Gy have a 75-90% local control rate. Neither systemic lymphoma nor PCNSL have a classic radiotherapy dose response. For PCNSL there appears to be a threshold dose that ranges in the literature between 30 and > 50 Gy with a median of 40 Gy. Therefore, when radiotherapy is combined with chemotherapy that crosses the BBB, WBRT and/or boost doses may be able to be decreased, especially in patients achieving a complete response. Promising data from the Centre Leon Berard suggest that this is possible. When such chemotherapy was combined with intrathecal chemotherapy and 20 Gy WBRT, they obtained a 56% actuarial 5 year survival rate. Confirmation of single institution reports of favorable results such as these are needed. Cooperative group and intergroup trials are needed to define optimal therapy.

  6. The Nano-X Linear Accelerator: A Compact and Economical Cancer Radiotherapy System Incorporating Patient Rotation.

    PubMed

    Eslick, Enid M; Keall, Paul J

    2015-10-01

    Rapid technological improvements in radiotherapy delivery results in improved outcomes to patients, yet current commercial systems with these technologies on board are costly. The aim of this study was to develop a state-of-the-art cancer radiotherapy system that is economical and space efficient fitting with current world demands. The Nano-X system is a compact design that is light weight combining a patient rotation system with a vertical 6 MV fixed beam. In this paper, we present the Nano-X system design configuration, an estimate of the system dimensions and its potential impact on shielding cost reductions. We provide an assessment of implementing such a radiotherapy system clinically, its advantages and disadvantages compared to a compact conventional gantry rotating linac. The Nano-X system has several differentiating features from current radiotherapy systems, it is [1] compact and therefore can fit into small vaults, [2] light weight, and [3] engineering efficient, i.e., it rotates a relatively light component and the main treatment delivery components are not under rotation (e.g., DMLCs). All these features can have an impact on reducing the costs of the system. In terms of shielding requirements, leakage radiation was found to be the dominant contributor to the Nano-X vault and as such no primary shielding was necessary. For a low leakage design, the Nano-X vault footprint and concrete volume required is 17 m2 and 35 m3 respectively, compared to 54 m2 and 102 m3 for a conventional compact linac vault, resulting in decreased costs in shielding. Key issues to be investigated in future work are the possible patient comfort concerns associated with the patient rotation system, as well as the magnitude of deformation and subsequent adaptation requirements.

  7. Knowledge-based computer systems for radiotherapy planning.

    PubMed

    Kalet, I J; Paluszynski, W

    1990-08-01

    Radiation therapy is one of the first areas of clinical medicine to utilize computers in support of routine clinical decision making. The role of the computer has evolved from simple dose calculations to elaborate interactive graphic three-dimensional simulations. These simulations can combine external irradiation from megavoltage photons, electrons, and particle beams with interstitial and intracavitary sources. With the flexibility and power of modern radiotherapy equipment and the ability of computer programs that simulate anything the machinery can do, we now face a challenge to utilize this capability to design more effective radiation treatments. How can we manage the increased complexity of sophisticated treatment planning? A promising approach will be to use artificial intelligence techniques to systematize our present knowledge about design of treatment plans, and to provide a framework for developing new treatment strategies. Far from replacing the physician, physicist, or dosimetrist, artificial intelligence-based software tools can assist the treatment planning team in producing more powerful and effective treatment plans. Research in progress using knowledge-based (AI) programming in treatment planning already has indicated the usefulness of such concepts as rule-based reasoning, hierarchical organization of knowledge, and reasoning from prototypes. Problems to be solved include how to handle continuously varying parameters and how to evaluate plans in order to direct improvements.

  8. Standard radiotherapy but not chemotherapy impairs systemic immunity in non-small cell lung cancer

    PubMed Central

    Talebian Yazdi, Mehrdad; Schinkelshoek, Mink S.; Loof, Nikki M.; Taube, Christian; Hiemstra, Pieter S.; Welters, Marij J. P.; van der Burg, Sjoerd H.

    2016-01-01

    ABSTRACT Introduction: Advanced non-small cell lung cancer (NSCLC) is traditionally treated with platinum-based chemotherapy and radiotherapy. Since immunotherapy holds promise for treating advanced NSCLC, we assessed the systemic effects of the traditional therapies for NSCLC on immune cell composition and function. Methods: 84 pulmonary adenocarcinoma patients, treated either with chemotherapy or radiotherapy, were studied. A prospective study of 23 patients was conducted in which the myeloid and lymphoid cell compartments of peripheral blood were analyzed. Changes in cell populations were validated in a retrospective cohort of 61 adenocarcinoma patients using automated differential counts collected throughout therapy. Furthermore, the functional capacity of circulating T cells and antigen-presenting cells (APC) was studied. Blood samples of healthy individuals were used as controls. Results: In comparison to healthy controls, untreated adenocarcinoma patients display an elevated frequency of myeloid cells coinciding with relative lower frequencies of lymphocytes and dendritic cells. Standard chemotherapy had no overt effects on myeloid and lymphoid cell composition nor on T-cell and APC-function. In contrast, patients treated with radiotherapy displayed a decrease in lymphoid cells and a relative increase in monocytes/macrophages. Importantly, these changes were associated with a reduced APC function and an impaired response of T cells to recall antigens. Conclusions: Platinum-based standard of care chemotherapy for NSCLC has no profound negative effect on the immune cell composition and function. The negative effect of prolonged low-dose radiotherapy on the immune system warrants future studies on the optimal dose and fraction of radiotherapy when combined with immunotherapy. PMID:28123900

  9. A noninvasive eye fixation monitoring system for CyberKnife radiotherapy of choroidal and orbital tumors

    SciTech Connect

    Daftari, I. K.; Petti, P. L.; Larson, D. A.; O'Brien, J. M.; Phillips, T. L.

    2009-03-15

    A new noninvasive monitoring system for fixing the eye has been developed to treat orbital and choroidal tumors with CyberKnife-based radiotherapy. This device monitors the eye during CT/MRI scanning and during treatment. The results of this study demonstrate the feasibility of the fixation light system for CyberKnife-based treatments of orbital and choroidal tumors and supports the idea that larger choroidal melanomas and choroidal metastases could be treated with CyberKnife without implanting fiducial markers.

  10. Verification of respiratory-gated radiotherapy with new real-time tumour-tracking radiotherapy system using cine EPID images and a log file

    NASA Astrophysics Data System (ADS)

    Shiinoki, Takehiro; Hanazawa, Hideki; Yuasa, Yuki; Fujimoto, Koya; Uehara, Takuya; Shibuya, Keiko

    2017-02-01

    A combined system comprising the TrueBeam linear accelerator and a new real-time tumour-tracking radiotherapy system, SyncTraX, was installed at our institution. The objectives of this study are to develop a method for the verification of respiratory-gated radiotherapy with SyncTraX using cine electronic portal image device (EPID) images and a log file and to verify this treatment in clinical cases. Respiratory-gated radiotherapy was performed using TrueBeam and the SyncTraX system. Cine EPID images and a log file were acquired for a phantom and three patients during the course of the treatment. Digitally reconstructed radiographs (DRRs) were created for each treatment beam using a planning CT set. The cine EPID images, log file, and DRRs were analysed using a developed software. For the phantom case, the accuracy of the proposed method was evaluated to verify the respiratory-gated radiotherapy. For the clinical cases, the intra- and inter-fractional variations of the fiducial marker used as an internal surrogate were calculated to evaluate the gating accuracy and set-up uncertainty in the superior–inferior (SI), anterior–posterior (AP), and left–right (LR) directions. The proposed method achieved high accuracy for the phantom verification. For the clinical cases, the intra- and inter-fractional variations of the fiducial marker were  ⩽3 mm and  ±3 mm in the SI, AP, and LR directions. We proposed a method for the verification of respiratory-gated radiotherapy with SyncTraX using cine EPID images and a log file and showed that this treatment is performed with high accuracy in clinical cases. This work was partly presented at the 58th Annual meeting of American Association of Physicists in Medicine.

  11. Verification of respiratory-gated radiotherapy with new real-time tumour-tracking radiotherapy system using cine EPID images and a log file.

    PubMed

    Shiinoki, Takehiro; Hanazawa, Hideki; Yuasa, Yuki; Fujimoto, Koya; Uehara, Takuya; Shibuya, Keiko

    2017-02-21

    A combined system comprising the TrueBeam linear accelerator and a new real-time tumour-tracking radiotherapy system, SyncTraX, was installed at our institution. The objectives of this study are to develop a method for the verification of respiratory-gated radiotherapy with SyncTraX using cine electronic portal image device (EPID) images and a log file and to verify this treatment in clinical cases. Respiratory-gated radiotherapy was performed using TrueBeam and the SyncTraX system. Cine EPID images and a log file were acquired for a phantom and three patients during the course of the treatment. Digitally reconstructed radiographs (DRRs) were created for each treatment beam using a planning CT set. The cine EPID images, log file, and DRRs were analysed using a developed software. For the phantom case, the accuracy of the proposed method was evaluated to verify the respiratory-gated radiotherapy. For the clinical cases, the intra- and inter-fractional variations of the fiducial marker used as an internal surrogate were calculated to evaluate the gating accuracy and set-up uncertainty in the superior-inferior (SI), anterior-posterior (AP), and left-right (LR) directions. The proposed method achieved high accuracy for the phantom verification. For the clinical cases, the intra- and inter-fractional variations of the fiducial marker were  ⩽3 mm and  ±3 mm in the SI, AP, and LR directions. We proposed a method for the verification of respiratory-gated radiotherapy with SyncTraX using cine EPID images and a log file and showed that this treatment is performed with high accuracy in clinical cases.

  12. Prototype development of an electrical impedance based simultaneous respiratory and cardiac monitoring system for gated radiotherapy.

    PubMed

    Kohli, Kirpal; Liu, Jeff; Schellenberg, Devin; Karvat, Anand; Parameswaran, Ash; Grewal, Parvind; Thomas, Steven

    2014-10-14

    In radiotherapy, temporary translocations of the internal organs and tumor induced by respiratory and cardiac activities can undesirably lead to significantly lower radiation dose on the targeted tumor but more harmful radiation on surrounding healthy tissues. Respiratory and cardiac gated radiotherapy offers a potential solution for the treatment of tumors located in the upper thorax. The present study focuses on the design and development of simultaneous acquisition of respiratory and cardiac signal using electrical impedance technology for use in dual gated radiotherapy. An electronic circuitry was developed for monitoring the bio-impedance change due to respiratory and cardiac motions and extracting the cardiogenic ECG signal. The system was analyzed in terms of reliability of signal acquisition, time delay, and functionality in a high energy radiation environment. The resulting signal of the system developed was also compared with the output of the commercially available Real-time Position Management™ (RPM) system in both time and frequency domains. The results demonstrate that the bioimpedance-based method can potentially provide reliable tracking of respiratory and cardiac motion in humans, alternative to currently available methods. When compared with the RPM system, the impedance-based system developed in the present study shows similar output pattern but different sensitivities in monitoring different respiratory rates. The tracking of cardiac motion was more susceptible to interference from other sources than respiratory motion but also provided synchronous output compared with the ECG signal extracted. The proposed hardware-based implementation was observed to have a worst-case time delay of approximately 33 ms for respiratory monitoring and 45 ms for cardiac monitoring. No significant effect on the functionality of the system was observed when it was tested in a radiation environment with the electrode lead wires directly exposed to high-energy X

  13. A method for measuring the dose distribution of the radiotherapy domain using the computed radiography system.

    PubMed

    Homma, Mitsuhiko; Tabushi, Katsuyoshi; Obata, Yasunori; Tamiya, Tadashi; Koyama, Shuji; Ishigaki, Takeo

    2002-01-01

    Knowing the dose distribution in a tissue is as important as being able to measure exposure or absorbed dose in radiotherapy. Therefore, we have developed a measurement method for the dose distribution (CR dosimetry) in the phantom based on the imaging plate (IP) of the computed radiography (CR). The IP was applied for the dose measurement as a dosimeter instead of the film used for film dosimetry. The data from the irradiated IP were processed by a personal computer with 10 bits and were depicted as absorbed dose distributions in the phantom. The image of the dose distribution was obtained from the CR system using the DICOM form. The CR dosimetry is an application of CR system currently employed in medical examinations to dosimetry in radiotherapy. A dose distribution can be easily shown by the Dose Distribution Depiction System we developed this time. Moreover, the measurement method is simpler and a result is obtained more quickly compared with film dosimetry.

  14. Systemic Lupus Erythematosus, Radiotherapy, and the Risk of Acute and Chronic Toxicity: The Mayo Clinic Experience

    SciTech Connect

    Pinn, Melva E.; Gold, Douglas G. M.; Petersen, Ivy A.; Osborn, Thomas G.; Brown, Paul D.; Miller, Robert C.

    2008-06-01

    Purpose: To determine the acute and chronic toxic effects of radiotherapy in patients with systemic lupus erythematosus (SLE). Methods and Materials: Medical records of 21 consecutive patients with SLE, who had received 34 courses of external beam radiotherapy and one low-dose-rate prostate implant, were retrospectively reviewed. Patients with discoid lupus erythematosus were excluded. Results: Median survival was 2.3 years and median follow-up 5.6 years. Eight (42%) of 19 patients evaluable for acute toxicity during radiotherapy experienced acute toxicity of Grade 1 or greater, and 4 (21%) had acute toxicity of Grade 3 or greater. The 5- and 10-year incidence of chronic toxicity of Grade 1 or greater was 45% (95% confidence interval [CI], 22-72%) and 56% (95% CI, 28-81%), respectively. The 5- and 10-year incidence of chronic toxicity of Grade 3 or greater was 28% (95% CI, 18-60%) and 40% (95% CI, 16-72%), respectively. Univariate analysis showed that chronic toxicity of Grade 1 or greater correlated with SLE renal involvement (p < 0.006) and possibly with the presence of five or more American Rheumatism Association criteria (p < 0.053). Chronic toxicity of Grade 3 or greater correlated with an absence of photosensitivity (p < 0.02), absence of arthritis (p < 0.03), and presence of a malar rash (p < 0.04). Conclusions: The risk of acute and chronic toxicity in patients with SLE who received radiotherapy was moderate but was not prohibitive of the use of radiotherapy. Patients with more advanced SLE may be at increased risk for chronic toxicity.

  15. A Simulation Study of a Radiofrequency Localization System for Tracking Patient Motion in Radiotherapy

    PubMed Central

    Ostyn, Mark; Kim, Siyong; Yeo, Woon-Hong

    2016-01-01

    One of the most widely used tools in cancer treatment is external beam radiotherapy. However, the major risk involved in radiotherapy is excess radiation dose to healthy tissue, exacerbated by patient motion. Here, we present a simulation study of a potential radiofrequency (RF) localization system designed to track intrafraction motion (target motion during the radiation treatment). This system includes skin-wearable RF beacons and an external tracking system. We develop an analytical model for direction of arrival measurement with radio frequencies (GHz range) for use in a localization estimate. We use a Monte Carlo simulation to investigate the relationship between a localization estimate and angular resolution of sensors (signal receivers) in a simulated room. The results indicate that the external sensor needs an angular resolution of about 0.03 degrees to achieve millimeter-level localization accuracy in a treatment room. This fundamental study of a novel RF localization system offers the groundwork to design a radiotherapy-compatible patient positioning system for active motion compensation. PMID:27089342

  16. A Simulation Study of a Radiofrequency Localization System for Tracking Patient Motion in Radiotherapy.

    PubMed

    Ostyn, Mark; Kim, Siyong; Yeo, Woon-Hong

    2016-04-13

    One of the most widely used tools in cancer treatment is external beam radiotherapy. However, the major risk involved in radiotherapy is excess radiation dose to healthy tissue, exacerbated by patient motion. Here, we present a simulation study of a potential radiofrequency (RF) localization system designed to track intrafraction motion (target motion during the radiation treatment). This system includes skin-wearable RF beacons and an external tracking system. We develop an analytical model for direction of arrival measurement with radio frequencies (GHz range) for use in a localization estimate. We use a Monte Carlo simulation to investigate the relationship between a localization estimate and angular resolution of sensors (signal receivers) in a simulated room. The results indicate that the external sensor needs an angular resolution of about 0.03 degrees to achieve millimeter-level localization accuracy in a treatment room. This fundamental study of a novel RF localization system offers the groundwork to design a radiotherapy-compatible patient positioning system for active motion compensation.

  17. Stereotactic Image-Guided Intensity Modulated Radiotherapy Using the HI-ART II Helical Tomotherapy System

    SciTech Connect

    Holmes, Timothy W. Hudes, Richard; Dziuba, Sylwester; Kazi, Abdul; Hall, Mark; Dawson, Dana

    2008-07-01

    The highly integrated adaptive radiation therapy (HI-ART II) helical tomotherapy unit is a new radiotherapy machine designed to achieve highly precise and accurate treatments at all body sites. The precision and accuracy of the HI-ART II is similar to that provided by stereotactic radiosurgery systems, hence the historical distinction between external beam radiotherapy and stereotactic procedures based on differing precision requirements is removed for this device. The objectives of this work are: (1) to describe stereotactic helical tomotherapy processes (SRS, SBRT); (2) to show that the precision and accuracy of the HI-ART meet the requirements defined for SRS and SBRT; and (3) to describe the clinical implementation of a stereotactic image-guided intensity modulated radiation therapy (IG-IMRT) system that incorporates optical motion management.

  18. Redesigning Radiotherapy Quality Assurance: Opportunities to Develop an Efficient, Evidence-Based System to Support Clinical Trials

    PubMed Central

    Bekelman, Justin E.; Deye, James A.; Vikram, Bhadrasain; Bentzen, Soren M.; Bruner, Deborah; Curran, Walter J.; Dignam, James; Efstathiou, Jason A.; FitzGerald, T. J.; Hurkmans, Coen; Ibbott, Geoffrey S.; Lee, J. Jack; Merchant, Timothy E.; Michalski, Jeff; Palta, Jatinder R.; Simon, Richard; Ten Haken, Randal K.; Timmerman, Robert; Tunis, Sean; Coleman, C. Norman; Purdy, James

    2012-01-01

    Background In the context of national calls for reorganizing cancer clinical trials, the National Cancer Institute (NCI) sponsored a two day workshop to examine the challenges and opportunities for optimizing radiotherapy quality assurance (QA) in clinical trial design. Methods Participants reviewed the current processes of clinical trial QA and noted the QA challenges presented by advanced technologies. Lessons learned from the radiotherapy QA programs of recent trials were discussed in detail. Four potential opportunities for optimizing radiotherapy QA were explored, including the use of normal tissue toxicity and tumor control metrics, biomarkers of radiation toxicity, new radiotherapy modalities like proton beam therapy, and the international harmonization of clinical trial QA. Results Four recommendations were made: 1) Develop a tiered (and more efficient) system for radiotherapy QA and tailor intensity of QA to clinical trial objectives. Tiers include (i) general credentialing, (ii) trial specific credentialing, and (iii) individual case review; 2) Establish a case QA repository; 3) Develop an evidence base for clinical trial QA and introduce innovative prospective trial designs to evaluate radiotherapy QA in clinical trials; and 4) Explore the feasibility of consolidating clinical trial QA in the United States. Conclusion Radiotherapy QA may impact clinical trial accrual, cost, outcomes and generalizability. To achieve maximum benefit, QA programs must become more efficient and evidence-based. PMID:22425219

  19. Evaluation of mechanical and geometric accuracy of two different image guidance systems in radiotherapy.

    PubMed

    Kanakavelu, Nithya; Ravindran, Anand Mambakam; Samuel, Emmanvelrajan James Jebaseelan

    2016-01-01

    To assess the mechanical and the geometric accuracy of two different clinically used image guidance systems in radiotherapy for a period of 6 months. With the image guidance procedures being routine in the clinical radiotherapy department, the quality assurance tests for these systems become essential. The mechanical and geometric accuracy of these systems are crucial since it directly affects patient treatment set-up and delivery. We have assessed the mechanical and the geometric accuracy of two different image guidance systems (MV and kV based), being used clinically for a period of 6 months. The quality assurance tests such as imager positioning/repositioning, imaging and treatment beam isocentre coincidence, imager mechanical alignment, image scaling, geometric accuracy of cone beam computed tomography system, automatic image registration and offset calculation accuracy were assessed in this period. It was found that both systems were mechanically and geometrically accurate within ±2 mm in this period. The quality assurance tests for MV based image guidance system were simple compared to kV based systems. We recommend performing periodic quality assurance tests to verify the integrity of both image guidance systems.

  20. Validation of different staging systems for hepatocellular carcinoma in a cohort of 249 patients undergoing radiotherapy

    PubMed Central

    Lu, Hui-Rong; Li, Ye-Fei; Liang, Shi-Xiong; Zhang, Chun-Yan

    2017-01-01

    There is no consensus on predicting prognosis for hepatocellular carcinoma patients undergoing radiotherapy. This study aims to evaluate the validity of different staging systems. Overall, 249 hepatocellular carcinoma patients were evaluated retrospectively. All patients were classified by different staging systems. The cumulative survival rates were calculated using the Kaplan-Meier method, and survival curves were compared using the log-rank test. Harrell's concordance index (c-index) was calculated. The 1-, 3-, and 5-year overall survival rates were 58%, 31% and 20%, respectively. Significant differences in overall survival were observed between stages I and II of the Okuda staging system (p=0.004), between scores of 3 and 4 of Cancer of the Liver Italian Program prognostic score (p=0.009), between Chinese University Prognostic Index low-risk and intermediate-risk groups (p=0.01), between 1 and 2 points of the Japan Integrated Staging score (p=0.037), between stages III and IV of American Joint Committee on Cancer 1997 TNM staging system (p=0.011), between stages II and III of American Joint Committee on Cancer 2002 TNM staging system (p=0.026) and between stages I and II of Guangzhou 2001 staging system (p=0.000). In conclusion, the Okuda staging system, Chinese University Prognostic Index, and Chinese Guangzhou 2001 staging system were more discriminative than the other staging systems in the prognostic stratification for hepatocellular carcinoma patients undergoing radiotherapy. PMID:28147327

  1. Development of a MicroCT-Based Image-Guided Conformal Radiotherapy System for Small Animals

    PubMed Central

    Zhou, Hu; Rodriguez, Manuel; van den Haak, Fred; Nelson, Geoffrey; Jogani, Rahil; Xu, Jiali; Zhu, Xinzhi; Xian, Yongjiang; Tran, Phuoc T.; Felsher, Dean W.; Keall, Paul J.; Graves, Edward E.

    2009-01-01

    Purpose The need for clinically-relevant radiation therapy technology for the treatment of preclinical models of disease has spurred the development of a variety of dedicated platforms for small animal irradiation. Our group has taken the approach of adding the ability to deliver conformal radiotherapy to an existing 120 kVp micro-computed tomography (microCT) scanner. Methods A GE eXplore RS120 microCT scanner was modified by the addition of a two-dimensional subject translation stage and a variable aperture collimator. Quality assurance protocols for these devices, including measurement of translation stage positioning accuracy, collimator aperture accuracy, and collimator alignment with the x-ray beam, were devised. Use of this system for image-guided radiotherapy was assessed by irradiation of a solid water phantom as well as of two mice bearing spontaneous MYC-induced lung tumors. Radiation damage was assessed ex vivo by immunohistochemical detection of γH2AX foci. Results The positioning error of the translation stage was found to be less than 0.05 mm, while after alignment of the collimator with the x-ray axis through adjustment of its displacement and rotation, the collimator aperture error was less than 0.1 mm measured at isocenter. CT image-guided treatment of a solid water phantom demonstrated target localization accuracy to within 0.1 mm. γH2AX foci were detected within irradiated lung tumors in mice, with contralateral lung tissue displaying background staining. Conclusions Addition of radiotherapy functionality to a microCT scanner is an effective means of introducing image-guided radiation treatments into the preclinical setting. This approach has been shown to facilitate small animal conformal radiotherapy while leveraging existing technology. PMID:20395069

  2. Comparative study of convolution, superposition, and fast superposition algorithms in conventional radiotherapy, three-dimensional conformal radiotherapy, and intensity modulated radiotherapy techniques for various sites, done on CMS XIO planning system

    PubMed Central

    Muralidhar, K. R.; Murthy, Narayana P.; Raju, Alluri Krishnam; Sresty, NVNM

    2009-01-01

    The aim of this study is to compare the dosimetry results that are obtained by using Convolution, Superposition and Fast Superposition algorithms in Conventional Radiotherapy, Three-Dimensional Conformal Radiotherapy (3D-CRT), and Intensity Modulated Radiotherapy (IMRT) for different sites, and to study the suitability of algorithms with respect to site and technique. For each of the Conventional, 3D-CRT, and IMRT techniques, four different sites, namely, Lung, Esophagus, Prostate, and Hypopharynx were analyzed. Treatment plans were created using 6MV Photon beam quality using the CMS XiO (Computerized Medical System, St.Louis, MO) treatment planning system. The maximum percentage of variation recorded between algorithms was 3.7% in case of Ca.Lung, for the IMRT Technique. Statistical analysis was performed by comparing the mean relative difference, Conformity Index, and Homogeneity Index for target structures. The fast superposition algorithm showed excellent results for lung and esophagus cases for all techniques. For the prostate, the superposition algorithm showed better results in all techniques. In the conventional case of the hypopharynx, the convolution algorithm was good. In case of Ca. Lung, Ca Prostate, Ca Esophagus, and Ca Hypopharynx, OARs got more doses with the superposition algorithm; this progressively decreased for fast superposition and convolution algorithms, respectively. According to this study the dosimetric results using different algorithms led to significant variation and therefore care had to be taken while evaluating treatment plans. The choice of a dose calculation algorithm may in certain cases even influence clinical results. PMID:20126561

  3. Geometrical verification system using Adobe Photoshop in radiotherapy.

    PubMed

    Ishiyama, Hiromichi; Suzuki, Koji; Niino, Keiji; Hosoya, Takaaki; Hayakawa, Kazushige

    2005-02-01

    Adobe Photoshop is used worldwide and is useful for comparing portal films with simulation films. It is possible to scan images and then view them simultaneously with this software. The purpose of this study was to assess the accuracy of a geometrical verification system using Adobe Photoshop. We prepared the following two conditions for verification. Under one condition, films were hanged on light boxes, and examiners measured distances between the isocenter on simulation films and that on portal films by adjusting the bony structures. Under the other condition, films were scanned into a computer and displayed using Adobe Photoshop, and examiners measured distances between the isocenter on simulation films and those on portal films by adjusting the bony structures. To obtain control data, lead balls were used as a fiducial point for matching the films accurately. The errors, defined as the differences between the control data and the measurement data, were assessed. Errors of the data obtained using Adobe Photoshop were significantly smaller than those of the data obtained from films on light boxes (p < 0.007). The geometrical verification system using Adobe Photoshop is available on any PC with this software and is useful for improving the accuracy of verification.

  4. SU-E-J-184: Stereo Time-Of-Flight System for Patient Positioning in Radiotherapy

    SciTech Connect

    Wentz, T; Gilles, M; Visvikis, D; Le Fur, E; Pradier, O

    2014-06-01

    Purpose: The objective of this work is to test the advantage of using the surface acquired by two stereo Time-of-Flight (ToF) cameras in comparison of the use of one camera only for patient positioning in radiotherapy. Methods: A first step consisted on validating the use of a stereo ToFcamera system for positioning management of a phantom mounted on a linear actuator producing very accurate and repeatable displacements. The displacements between two positions were computed from the surface point cloud acquired by either one or two cameras thanks to an iterative closest point algorithm. A second step consisted on determining the displacements on patient datasets, with two cameras fixed on the ceiling of the radiotherapy room. Measurements were done first on voluntary subject with fixed translations, then on patients during the normal clinical radiotherapy routine. Results: The phantom tests showed a major improvement in lateral and depth axis for motions above 10 mm when using the stereo-system instead of a unique camera (Fig1). Patient measurements validate these results with a mean real and measured displacement differences in the depth direction of 1.5 mm when using one camera and 0.9 mm when using two cameras (Fig2). In the lateral direction, a mean difference of 1 mm was obtained by the stereo-system instead of 3.2 mm. Along the longitudinal axis mean differences of 5.4 and 3.4 mm with one and two cameras respectively were noticed but these measurements were still inaccurate and globally underestimated in this direction as in the literature. Similar results were also found for patient subjects with a mean difference reduction of 35%, 7%, and 25% for the lateral, depth, and longitudinal displacement with the stereo-system. Conclusion: The addition of a second ToF-camera to determine patient displacement strongly improved patient repositioning results and therefore insures better radiation delivery.

  5. Patient dosimetry for hybrid MRI-radiotherapy systems.

    PubMed

    Kirkby, C; Stanescu, T; Rathee, S; Carlone, M; Murray, B; Fallone, B G

    2008-03-01

    A novel geometry has been proposed for a hybrid magnetic resonance imaging (MRI)-linac system in which a 6 MV linac is mounted on the open end of a biplanar, low field (0.2 T) MRI magnet on a single gantry that is free to rotate around the patient. This geometry creates a scenario in which the magnetic field vector remains fixed with respect to the incident photon beam, but moves with respect to the patient as the gantry rotates. Other proposed geometries are characterized by a radiation source rotating about a fixed cylindrical magnet where the magnetic field vector remains fixed with respect to the patient. In this investigation we simulate the inherent dose distribution patterns within the two MRI-radiation source geometries using PENELOPE and EGSnrc Monte Carlo radiation transport codes with algorithms implemented to account for the magnetic field deflection of charged particles. Simulations are performed in phantoms and for clinically realistic situations. The novel geometry results in a net Lorentz force that remains fixed with respect to the patient (in the cranial-caudal direction) and results in a cumulative influence on dose distribution for a multiple beam treatment scenario. For a case where patient anatomy is reasonably homogeneous (brain plan), differences in dose compared to a conventional (no magnetic field) case are minimal for the novel geometry. In the case of a lung plan where the inhomogeneous patient anatomy allows for the magnetic field to have significant influence on charged particle transport, larger differences occur in a predictable manner. For a system using a fixed cylindrical geometry and higher magnetic field (1.5 T), differences from the case without a magnetic field are significantly greater.

  6. Retrieval with Clustering in a Case-Based Reasoning System for Radiotherapy Treatment Planning

    NASA Astrophysics Data System (ADS)

    Khussainova, Gulmira; Petrovic, Sanja; Jagannathan, Rupa

    2015-05-01

    Radiotherapy treatment planning aims to deliver a sufficient radiation dose to cancerous tumour cells while sparing healthy organs in the tumour surrounding area. This is a trial and error process highly dependent on the medical staff's experience and knowledge. Case-Based Reasoning (CBR) is an artificial intelligence tool that uses past experiences to solve new problems. A CBR system has been developed to facilitate radiotherapy treatment planning for brain cancer. Given a new patient case the existing CBR system retrieves a similar case from an archive of successfully treated patient cases with the suggested treatment plan. The next step requires adaptation of the retrieved treatment plan to meet the specific demands of the new case. The CBR system was tested by medical physicists for the new patient cases. It was discovered that some of the retrieved cases were not suitable and could not be adapted for the new cases. This motivated us to revise the retrieval mechanism of the existing CBR system by adding a clustering stage that clusters cases based on their tumour positions. A number of well-known clustering methods were investigated and employed in the retrieval mechanism. Results using real world brain cancer patient cases have shown that the success rate of the new CBR retrieval is higher than that of the original system.

  7. Accurate calibration of a stereo-vision system in image-guided radiotherapy

    SciTech Connect

    Liu Dezhi; Li Shidong

    2006-11-15

    Image-guided radiotherapy using a three-dimensional (3D) camera as the on-board surface imaging system requires precise and accurate registration of the 3D surface images in the treatment machine coordinate system. Two simple calibration methods, an analytical solution as three-point matching and a least-squares estimation method as multipoint registration, were introduced to correlate the stereo-vision surface imaging frame with the machine coordinate system. Both types of calibrations utilized 3D surface images of a calibration template placed on the top of the treatment couch. Image transformational parameters were derived from corresponding 3D marked points on the surface images to their given coordinates in the treatment room coordinate system. Our experimental results demonstrated that both methods had provided the desired calibration accuracy of 0.5 mm. The multipoint registration method is more robust particularly for noisy 3D surface images. Both calibration methods have been used as our weekly QA tools for a 3D image-guided radiotherapy system.

  8. Monte Carlo treatment planning for molecular targeted radiotherapy within the MINERVA system

    NASA Astrophysics Data System (ADS)

    Lehmann, Joerg; Hartmann Siantar, Christine; Wessol, Daniel E.; Wemple, Charles A.; Nigg, David; Cogliati, Josh; Daly, Tom; Descalle, Marie-Anne; Flickinger, Terry; Pletcher, David; DeNardo, Gerald

    2005-03-01

    The aim of this project is to extend accurate and patient-specific treatment planning to new treatment modalities, such as molecular targeted radiation therapy, incorporating previously crafted and proven Monte Carlo and deterministic computation methods. A flexible software environment is being created that allows planning radiation treatment for these new modalities and combining different forms of radiation treatment with consideration of biological effects. The system uses common input interfaces, medical image sets for definition of patient geometry and dose reporting protocols. Previously, the Idaho National Engineering and Environmental Laboratory (INEEL), Montana State University (MSU) and Lawrence Livermore National Laboratory (LLNL) had accrued experience in the development and application of Monte Carlo based, three-dimensional, computational dosimetry and treatment planning tools for radiotherapy in several specialized areas. In particular, INEEL and MSU have developed computational dosimetry systems for neutron radiotherapy and neutron capture therapy, while LLNL has developed the PEREGRINE computational system for external beam photon-electron therapy. Building on that experience, the INEEL and MSU are developing the MINERVA (modality inclusive environment for radiotherapeutic variable analysis) software system as a general framework for computational dosimetry and treatment planning for a variety of emerging forms of radiotherapy. In collaboration with this development, LLNL has extended its PEREGRINE code to accommodate internal sources for molecular targeted radiotherapy (MTR), and has interfaced it with the plugin architecture of MINERVA. Results from the extended PEREGRINE code have been compared to published data from other codes, and found to be in general agreement (EGS4—2%, MCNP—10%) (Descalle et al 2003 Cancer Biother. Radiopharm. 18 71-9). The code is currently being benchmarked against experimental data. The interpatient variability of

  9. Monte Carlo Treatment Planning for Molecular Targeted Radiotherapy within the MINERVA System

    SciTech Connect

    Lehmann, J; Siantar, C H; Wessol, D E; Wemple, C A; Nigg, D; Cogliati, J; Daly, T; Descalle, M; Flickinger, T; Pletcher, D; DeNardo, G

    2004-09-22

    The aim of this project is to extend accurate and patient-specific treatment planning to new treatment modalities, such as molecular targeted radiation therapy, incorporating previously crafted and proven Monte Carlo and deterministic computation methods. A flexible software environment is being created that allows planning radiation treatment for these new modalities and combining different forms of radiation treatment with consideration of biological effects. The system uses common input interfaces, medical image sets for definition of patient geometry, and dose reporting protocols. Previously, the Idaho National Engineering and Environmental Laboratory (INEEL), Montana State University (MSU), and Lawrence Livermore National Laboratory (LLNL) had accrued experience in the development and application of Monte Carlo-based, three-dimensional, computational dosimetry and treatment planning tools for radiotherapy in several specialized areas. In particular, INEEL and MSU have developed computational dosimetry systems for neutron radiotherapy and neutron capture therapy, while LLNL has developed the PEREGRINE computational system for external beam photon-electron therapy. Building on that experience, the INEEL and MSU are developing the MINERVA (Modality Inclusive Environment for Radiotherapeutic Variable Analysis) software system as a general framework for computational dosimetry and treatment planning for a variety of emerging forms of radiotherapy. In collaboration with this development, LLNL has extended its PEREGRINE code to accommodate internal sources for molecular targeted radiotherapy (MTR), and has interfaced it with the plug-in architecture of MINERVA. Results from the extended PEREGRINE code have been compared to published data from other codes, and found to be in general agreement (EGS4 - 2%, MCNP - 10%)(Descalle et al. 2003). The code is currently being benchmarked against experimental data. The interpatient variability of the drug pharmacokinetics in MTR

  10. Monte Carlo treatment planning for molecular targeted radiotherapy within the MINERVA system.

    PubMed

    Lehmann, Joerg; Hartmann Siantar, Christine; Wessol, Daniel E; Wemple, Charles A; Nigg, David; Cogliati, Josh; Daly, Tom; Descalle, Marie-Anne; Flickinger, Terry; Pletcher, David; Denardo, Gerald

    2005-03-07

    The aim of this project is to extend accurate and patient-specific treatment planning to new treatment modalities, such as molecular targeted radiation therapy, incorporating previously crafted and proven Monte Carlo and deterministic computation methods. A flexible software environment is being created that allows planning radiation treatment for these new modalities and combining different forms of radiation treatment with consideration of biological effects. The system uses common input interfaces, medical image sets for definition of patient geometry and dose reporting protocols. Previously, the Idaho National Engineering and Environmental Laboratory (INEEL), Montana State University (MSU) and Lawrence Livermore National Laboratory (LLNL) had accrued experience in the development and application of Monte Carlo based, three-dimensional, computational dosimetry and treatment planning tools for radiotherapy in several specialized areas. In particular, INEEL and MSU have developed computational dosimetry systems for neutron radiotherapy and neutron capture therapy, while LLNL has developed the PEREGRINE computational system for external beam photon-electron therapy. Building on that experience, the INEEL and MSU are developing the MINERVA (modality inclusive environment for radiotherapeutic variable analysis) software system as a general framework for computational dosimetry and treatment planning for a variety of emerging forms of radiotherapy. In collaboration with this development, LLNL has extended its PEREGRINE code to accommodate internal sources for molecular targeted radiotherapy (MTR), and has interfaced it with the plugin architecture of MINERVA. Results from the extended PEREGRINE code have been compared to published data from other codes, and found to be in general agreement (EGS4-2%, MCNP-10%) (Descalle et al 2003 Cancer Biother. Radiopharm. 18 71-9). The code is currently being benchmarked against experimental data. The interpatient variability of the

  11. Assessment of performance indicators of a radiotherapy department using an electronic medical record system.

    PubMed

    Bahadur, Yasir A; Constantinescu, Camelia; Bahadur, Ammar Y; Bahadur, Ruba Y

    2017-01-01

    To retrospectively assess the performance indicators of our radiotherapy department and their temporal trends, using a commercially available electronic-medical-record (EMR) system. A recent trend in healthcare quality is to define and evaluate performance indicators of the service provided. Patient and external-beam-radiotherapy-treatments data were retrieved using the Mosaiq EMR system from 1-January-2012 till 31-December-2015. Annual performance indicators were evaluated as: productivity (number of new cases/year and diagnosis distribution); complexity (ratio of Volumetric-Modulated-Arc-Therapy (VMAT) courses, average number of imaging procedures/patient); and quality (average, median and 90th percentile waiting times from admission to first treatment). The temporal trends of all performance indicators were assessed by linear regression. Productivity: the number of new cases/year increased with an average rate of 4%. Diagnosis distribution showed that breast is the main pathology treated, followed by gastro-intestinal and head-and-neck. Complexity: the ratio of VMAT courses increased from 13% to 35%, with an average rate of 7% per year. The average number of imaging procedures/patient increased from 8 to 11. Quality: the waiting times from admission to treatment remained stable over time (R(2) ≤ 0.1), with average, median and 90th percentile values around 20, 15, and 31 days, respectively. An EMR system can be used to: monitor the performance indicators of a radiotherapy department, identify workflow processes needing attention and improvement, estimate future demands of resources. Temporal analysis of our data showed an increasing trend in productivity and complexity paired with constant waiting times.

  12. An integrated Monte Carlo dosimetric verification system for radiotherapy treatment planning

    NASA Astrophysics Data System (ADS)

    Yamamoto, T.; Mizowaki, T.; Miyabe, Y.; Takegawa, H.; Narita, Y.; Yano, S.; Nagata, Y.; Teshima, T.; Hiraoka, M.

    2007-04-01

    An integrated Monte Carlo (MC) dose calculation system, MCRTV (Monte Carlo for radiotherapy treatment plan verification), has been developed for clinical treatment plan verification, especially for routine quality assurance (QA) of intensity-modulated radiotherapy (IMRT) plans. The MCRTV system consists of the EGS4/PRESTA MC codes originally written for particle transport through the accelerator, the multileaf collimator (MLC), and the patient/phantom, which run on a 28-CPU Linux cluster, and the associated software developed for the clinical implementation. MCRTV has an interface with a commercial treatment planning system (TPS) (Eclipse, Varian Medical Systems, Palo Alto, CA, USA) and reads the information needed for MC computation transferred in DICOM-RT format. The key features of MCRTV have been presented in detail in this paper. The phase-space data of our 15 MV photon beam from a Varian Clinac 2300C/D have been developed and several benchmarks have been performed under homogeneous and several inhomogeneous conditions (including water, aluminium, lung and bone media). The MC results agreed with the ionization chamber measurements to within 1% and 2% for homogeneous and inhomogeneous conditions, respectively. The MC calculation for a clinical prostate IMRT treatment plan validated the implementation of the beams and the patient/phantom configuration in MCRTV.

  13. Integration of second cancer risk calculations in a radiotherapy treatment planning system

    NASA Astrophysics Data System (ADS)

    Hartmann, M.; Schneider, U.

    2014-03-01

    Second cancer risk in patients, in particular in children, who were treated with radiotherapy is an important side effect. It should be minimized by selecting an appropriate treatment plan for the patient. The objectives of this study were to integrate a risk model for radiation induced cancer into a treatment planning system which allows to judge different treatment plans with regard to second cancer induction and to quantify the potential reduction in predicted risk. A model for radiation induced cancer including fractionation effects which is valid for doses in the radiotherapy range was integrated into a treatment planning system. From the three-dimensional (3D) dose distribution the 3D-risk equivalent dose (RED) was calculated on an organ specific basis. In addition to RED further risk coefficients like OED (organ equivalent dose), EAR (excess absolute risk) and LAR (lifetime attributable risk) are computed. A risk model for radiation induced cancer was successfully integrated in a treatment planning system. Several risk coefficients can be viewed and used to obtain critical situations were a plan can be optimised. Risk-volume-histograms and organ specific risks were calculated for different treatment plans and were used in combination with NTCP estimates for plan evaluation. It is concluded that the integration of second cancer risk estimates in a commercial treatment planning system is feasible. It can be used in addition to NTCP modelling for optimising treatment plans which result in the lowest possible second cancer risk for a patient.

  14. Evaluation of performance of portable respiratory monitoring system based on micro-electro-mechanical-system for respiratory gated radiotherapy

    NASA Astrophysics Data System (ADS)

    Moon, Sun Young; Sung, Jiwon; Yoon, Myonggeun; Chung, Mijoo; Chung, Weon Kuu; Kim, Dong Wook

    2015-08-01

    In respiratory-gated radiotherapy of patients with lung or liver cancer, the patient's respiratory pattern and repeatability are important factors affecting therapy accuracy; it has been reported that these factors can be controlled if patients undergo respiration training. As such, this study evaluates the feasibility of micro-electro-mechanical-system (MEMS) in radiotherapy by investigating the effect of radiation on a miniature portable respiratory monitoring system based on the MEMS system, which is currently under development. Using a patient respiration simulation phantom, the time-acceleration graph measured by a normal sensor according to the phantom's respiratory movement before irradiation and the change in this graph with accumulated dose were compared using the baseline slope and the change in amplitude and period of the sine wave. The results showed that with a 400Gy accumulated dose in the sensor, a baseline shift occurred and both the amplitude and period changed. As a result, if the MEMS is applied in respiratory-gated radiotherapy, the sensor should be replaced after use with roughly 6-10 patients so as to ensure continued therapy accuracy, based on the characteristics of the sensor itself. In the future, a more diverse range of sensors should be similarly evaluated.

  15. Development of an integral system test for image-guided radiotherapy

    SciTech Connect

    Rowbottom, Carl G.; Jaffray, David A.

    2004-12-01

    An integral system test was developed to determine the precision and accuracy of an image-guided radiotherapy system involving an x-ray volumetric imaging device mounted onto the gantry of a medical linear accelerator. The test was designed to interrogate the system components as a whole without deconstructing the individual sources of error. The integral system test was based on the imaging of an unambiguous stationary object in the treatment position and so took no account of patient related errors. An array of micromosfets interspersed within slices of a tissue equivalent phantom was developed as an imaging test object. It has previously been demonstrated that micromosfets have a very small active volume, are clearly visible on CT images, and produce no significant artifacts. In addition, the active volume of the micromosfets can be accurately inferred radiographically via the use of x-ray volumetric imaging. X-ray volumetric imaging was performed with the object in the treatment position, then reconstructed and transferred to a treatment planning system. With the phantom remaining undisturbed in the treatment position a series of treatment fields were designed to produce a series of fields with the leaf edge sweeping across active volume of the micromosfets. The fields were delivered with a micro-MLC to dosimetrically verify the position of the mosfets and compare with dose values produced by the treatment planning system. It was demonstrated that the systematic gantry flex could be accounted for by the imaging and delivery systems. For the delivery system small changes in leaf positions of the micro-MLC were required to account for gantry flex. The position of the micromosfets determined by the 50% dose position was on average (0.15{+-}0.13) mm away from the position determined radiographically for the x and y axes, and (1.0{+-}0.14) mm for the z axis. This implies that a margin of approximately 0.2 mm in the axial plane and 1.0 mm in the superior

  16. A prognostic scoring system for locoregional control in nasopharyngeal carcinoma following conformal radiotherapy

    SciTech Connect

    Cheng, S.H.; Tsai, S.Y.; Horng, C.-F.; Yen, K.L.; Jian, James J.; Chan, Kwan-Yee; Lin, C.-Y.; Terng, S.-D.; Tsou, M.-H.; Chu, N.-M.; Chen, H.-H.; Hsieh, C.-I.; Tan, T.-D.; Chen, P.-L.; Chung, Y.L.; Huang, Andrew T. |

    2006-11-15

    Purpose: This study established a prognostic scoring system for nasopharyngeal carcinoma (NPC), which estimates the probability of locoregional (LR) control following definitive conformal radiotherapy. Methods and Materials: Patients with nondisseminated NPC at initial presentation (n = 630) were enrolled in this study. All patients had magnetic resonance imaging of the head and neck and were treated with conformal radiotherapy. Among them, 93% had concurrent chemotherapy, and 76% had postradiation chemotherapy. The extent of the primary tumor, age at diagnosis, primary tumor size, tumor and nodal classification, histology, and serum lactate dehydrogenase (LDH) level before treatment were included in the analysis for building a prognostic scoring system. The end point for this study was LR control. Results: The prognostic score was defined as the number of adverse prognostic factors present at diagnosis. Four factors had similarly independent prognostic effects (hazard ratio, 2.0-2.6): age >40 years, histologic WHO type I-II, serum LDH level {>=}410 U/L, and involvement of two or more sites of the following anatomic structures, i.e., sphenoid floor, clivus marrow, clivus cortex, prevertebral muscles, and petrous bone. The score predicted the 5-year probability of LR control as follows: 0 (15% of the patients), 100%; 1 (42% of the patients), 93%; 2 (29% of the patients), 83%; 3 or higher (13% of the patients), 71%. Conclusion: This scoring system is useful in the decision-making for individual patients and the design of clinical trials to improve LR control for advanced-stage NPC.

  17. Dosimetric inter-institutional comparison in European radiotherapy centres: Results of IAEA supported treatment planning system audit.

    PubMed

    Gershkevitsh, Eduard; Pesznyak, Csilla; Petrovic, Borislava; Grezdo, Joseph; Chelminski, Krzysztof; do Carmo Lopes, Maria; Izewska, Joanna; Van Dyk, Jacob

    2014-05-01

    One of the newer audit modalities operated by the International Atomic Energy Agency (IAEA) involves audits of treatment planning systems (TPS) in radiotherapy. The main focus of the audit is the dosimetry verification of the delivery of a radiation treatment plan for three-dimensional (3D) conformal radiotherapy using high energy photon beams. The audit has been carried out in eight European countries - Estonia, Hungary, Latvia, Lithuania, Serbia, Slovakia, Poland and Portugal. The corresponding results are presented. The TPS audit reviews the dosimetry, treatment planning and radiotherapy delivery processes using the 'end-to-end' approach, i.e. following the pathway similar to that of the patient, through imaging, treatment planning and dose delivery. The audit is implemented at the national level with IAEA assistance. The national counterparts conduct the TPS audit at local radiotherapy centres through on-site visits. TPS calculated doses are compared with ion chamber measurements performed in an anthropomorphic phantom for eight test cases per algorithm/beam. A set of pre-defined agreement criteria is used to analyse the performance of TPSs. TPS audit was carried out in 60 radiotherapy centres. In total, 190 data sets (combination of algorithm and beam quality) have been collected and reviewed. Dosimetry problems requiring interventions were discovered in about 10% of datasets. In addition, suboptimal beam modelling in TPSs was discovered in a number of cases. The TPS audit project using the IAEA methodology has verified the treatment planning system calculations for 3D conformal radiotherapy in a group of radiotherapy centres in Europe. It contributed to achieving better understanding of the performance of TPSs and helped to resolve issues related to imaging, dosimetry and treatment planning.

  18. Multi-Kinect v2 Camera Based Monitoring System for Radiotherapy Patient Safety.

    PubMed

    Santhanam, Anand P; Min, Yugang; Kupelian, Patrick; Low, Daniel

    2016-01-01

    3D kinect camera systems are essential for real-time imaging of 3D treatment space that consists of both the patient anatomy as well as the treatment equipment setup. In this paper, we present the technical details of a 3D treatment room monitoring system that employs a scalable number of calibrated and coregistered Kinect v2 cameras. The monitoring system tracks radiation gantry and treatment couch positions, and tracks the patient and immobilization accessories. The number and positions of the cameras were selected to avoid line-of-sight issues and to adequately cover the treatment setup. The cameras were calibrated with a calibration error of 0.1 mm. Our tracking system evaluation show that both gantry and patient motion could be acquired at a rate of 30 frames per second. The transformations between the cameras yielded a 3D treatment space accuracy of < 2 mm error in a radiotherapy setup within 500mm around the isocenter.

  19. Radiolucent 4D Ultrasound Imaging: System Design and Application to Radiotherapy Guidance.

    PubMed

    Schlosser, Jeffrey; Hristov, Dimitre

    2016-04-27

    Four-dimensional (4D) ultrasound (US) is an attractive modality for image guidance due to its real-time, non-ionizing, volumetric imaging capability with high soft tissue contrast. However, existing 4D US imaging systems contain large volumes of metal which interfere with diagnostic and therapeutic ionizing radiation in procedures such as CT imaging and radiation therapy. This study aimed to design and characterize a novel 4D Radiolucent Remotely-Actuated UltraSound Scanning (RRUSS) device that overcomes this limitation. In a phantom, we evaluated the imaging performance of the RRUSS device including frame rate, resolution, spatial integrity, and motion tracking accuracy. To evaluate compatibility with radiation therapy workflow, we evaluated device-induced CT imaging artifacts, US tracking performance during beam delivery, and device compatibility with commercial radiotherapy planning software. The RRUSS device produced 4D volumes at 0.1-3.0 Hz with 60⁰ lateral field of view (FOV), 50⁰ maximum elevational FOV, and 200 mm maximum depth. Imaging resolution (-3 dB point spread width) was 1.2-7.9 mm at depths up to 100 mm and motion tracking accuracy was ≤0.3±0.5 mm. No significant effect of the RRUSS device on CT image integrity was found, and RRUSS device performance was not affected by radiotherapy beam exposure. Agreement within ±3.0% / 2.0 mm was achieved between computed and measured radiotherapy dose delivered directly through the RRUSS device at 6 MV and 15 MV. In-vivo liver, kidney, and prostate images were successfully acquired. Our investigations suggest that a RRUSS device can offer non-interfering 4D guidance for radiation therapy and other diagnostic and therapeutic procedures.

  20. Radiolucent 4D Ultrasound Imaging: System Design and Application to Radiotherapy Guidance.

    PubMed

    Schlosser, Jeffrey; Hristov, Dimitre

    2016-10-01

    Four-dimensional (4D) ultrasound (US) is an attractive modality for image guidance due to its real-time, non-ionizing, volumetric imaging capability with high soft tissue contrast. However, existing 4D US imaging systems contain large volumes of metal which interfere with diagnostic and therapeutic ionizing radiation in procedures such as CT imaging and radiation therapy. This study aimed to design and characterize a novel 4D Radiolucent Remotely-Actuated UltraSound Scanning (RRUSS) device that overcomes this limitation. In a phantom, we evaluated the imaging performance of the RRUSS device including frame rate, resolution, spatial integrity, and motion tracking accuracy. To evaluate compatibility with radiation therapy workflow, we evaluated device-induced CT imaging artifacts, US tracking performance during beam delivery, and device compatibility with commercial radiotherapy planning software. The RRUSS device produced 4D volumes at 0.1-3.0 Hz with 60° lateral field of view (FOV), 50° maximum elevational FOV, and 200 mm maximum depth. Imaging resolution (-3 dB point spread width) was 1.2-7.9 mm at depths up to 100 mm and motion tracking accuracy was ≤ 0.3±0.5 mm. No significant effect of the RRUSS device on CT image integrity was found, and RRUSS device performance was not affected by radiotherapy beam exposure. Agreement within ±3.0% / 2.0 mm was achieved between computed and measured radiotherapy dose delivered directly through the RRUSS device at 6 MV and 15 MV. In vivo liver, kidney, and prostate images were successfully acquired. Our investigations suggest that a RRUSS device can offer non-interfering 4D guidance for radiation therapy and other diagnostic and therapeutic procedures.

  1. Implementation of an Analytical Model for Leakage Neutron Equivalent Dose in a Proton Radiotherapy Planning System

    PubMed Central

    Eley, John; Newhauser, Wayne; Homann, Kenneth; Howell, Rebecca; Schneider, Christopher; Durante, Marco; Bert, Christoph

    2015-01-01

    Equivalent dose from neutrons produced during proton radiotherapy increases the predicted risk of radiogenic late effects. However, out-of-field neutron dose is not taken into account by commercial proton radiotherapy treatment planning systems. The purpose of this study was to demonstrate the feasibility of implementing an analytical model to calculate leakage neutron equivalent dose in a treatment planning system. Passive scattering proton treatment plans were created for a water phantom and for a patient. For both the phantom and patient, the neutron equivalent doses were small but non-negligible and extended far beyond the therapeutic field. The time required for neutron equivalent dose calculation was 1.6 times longer than that required for proton dose calculation, with a total calculation time of less than 1 h on one processor for both treatment plans. Our results demonstrate that it is feasible to predict neutron equivalent dose distributions using an analytical dose algorithm for individual patients with irregular surfaces and internal tissue heterogeneities. Eventually, personalized estimates of neutron equivalent dose to organs far from the treatment field may guide clinicians to create treatment plans that reduce the risk of late effects. PMID:25768061

  2. Implementation of an analytical model for leakage neutron equivalent dose in a proton radiotherapy planning system.

    PubMed

    Eley, John; Newhauser, Wayne; Homann, Kenneth; Howell, Rebecca; Schneider, Christopher; Durante, Marco; Bert, Christoph

    2015-03-11

    Equivalent dose from neutrons produced during proton radiotherapy increases the predicted risk of radiogenic late effects. However, out-of-field neutron dose is not taken into account by commercial proton radiotherapy treatment planning systems. The purpose of this study was to demonstrate the feasibility of implementing an analytical model to calculate leakage neutron equivalent dose in a treatment planning system. Passive scattering proton treatment plans were created for a water phantom and for a patient. For both the phantom and patient, the neutron equivalent doses were small but non-negligible and extended far beyond the therapeutic field. The time required for neutron equivalent dose calculation was 1.6 times longer than that required for proton dose calculation, with a total calculation time of less than 1 h on one processor for both treatment plans. Our results demonstrate that it is feasible to predict neutron equivalent dose distributions using an analytical dose algorithm for individual patients with irregular surfaces and internal tissue heterogeneities. Eventually, personalized estimates of neutron equivalent dose to organs far from the treatment field may guide clinicians to create treatment plans that reduce the risk of late effects.

  3. Redesigning radiotherapy quality assurance: opportunities to develop an efficient, evidence-based system to support clinical trials--report of the National Cancer Institute Work Group on Radiotherapy Quality Assurance.

    PubMed

    Bekelman, Justin E; Deye, James A; Vikram, Bhadrasain; Bentzen, Soren M; Bruner, Deborah; Curran, Walter J; Dignam, James; Efstathiou, Jason A; FitzGerald, T J; Hurkmans, Coen; Ibbott, Geoffrey S; Lee, J Jack; Merchant, Thomas E; Michalski, Jeff; Palta, Jatinder R; Simon, Richard; Ten Haken, Randal K; Timmerman, Robert; Tunis, Sean; Coleman, C Norman; Purdy, James

    2012-07-01

    In the context of national calls for reorganizing cancer clinical trials, the National Cancer Institute sponsored a 2-day workshop to examine challenges and opportunities for optimizing radiotherapy quality assurance (QA) in clinical trial design. Participants reviewed the current processes of clinical trial QA and noted the QA challenges presented by advanced technologies. The lessons learned from the radiotherapy QA programs of recent trials were discussed in detail. Four potential opportunities for optimizing radiotherapy QA were explored, including the use of normal tissue toxicity and tumor control metrics, biomarkers of radiation toxicity, new radiotherapy modalities such as proton beam therapy, and the international harmonization of clinical trial QA. Four recommendations were made: (1) to develop a tiered (and more efficient) system for radiotherapy QA and tailor the intensity of QA to the clinical trial objectives (tiers include general credentialing, trial-specific credentialing, and individual case review); (2) to establish a case QA repository; (3) to develop an evidence base for clinical trial QA and introduce innovative prospective trial designs to evaluate radiotherapy QA in clinical trials; and (4) to explore the feasibility of consolidating clinical trial QA in the United States. Radiotherapy QA can affect clinical trial accrual, cost, outcomes, and generalizability. To achieve maximum benefit, QA programs must become more efficient and evidence-based. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Redesigning Radiotherapy Quality Assurance: Opportunities to Develop an Efficient, Evidence-Based System to Support Clinical Trials-Report of the National Cancer Institute Work Group on Radiotherapy Quality Assurance

    SciTech Connect

    Bekelman, Justin E.; Deye, James A.; Vikram, Bhadrasain; Bentzen, Soren M.; Bruner, Deborah; Curran, Walter J.; Dignam, James; Efstathiou, Jason A.; FitzGerald, T.J.; Hurkmans, Coen; Ibbott, Geoffrey S.; Lee, J. Jack; Merchant, Thomas E.; Michalski, Jeff; Palta, Jatinder R.; Simon, Richard; Ten Haken, Randal K.; Timmerman, Robert; Tunis, Sean; Coleman, C. Norman; and others

    2012-07-01

    Purpose: In the context of national calls for reorganizing cancer clinical trials, the National Cancer Institute sponsored a 2-day workshop to examine challenges and opportunities for optimizing radiotherapy quality assurance (QA) in clinical trial design. Methods and Materials: Participants reviewed the current processes of clinical trial QA and noted the QA challenges presented by advanced technologies. The lessons learned from the radiotherapy QA programs of recent trials were discussed in detail. Four potential opportunities for optimizing radiotherapy QA were explored, including the use of normal tissue toxicity and tumor control metrics, biomarkers of radiation toxicity, new radiotherapy modalities such as proton beam therapy, and the international harmonization of clinical trial QA. Results: Four recommendations were made: (1) to develop a tiered (and more efficient) system for radiotherapy QA and tailor the intensity of QA to the clinical trial objectives (tiers include general credentialing, trial-specific credentialing, and individual case review); (2) to establish a case QA repository; (3) to develop an evidence base for clinical trial QA and introduce innovative prospective trial designs to evaluate radiotherapy QA in clinical trials; and (4) to explore the feasibility of consolidating clinical trial QA in the United States. Conclusion: Radiotherapy QA can affect clinical trial accrual, cost, outcomes, and generalizability. To achieve maximum benefit, QA programs must become more efficient and evidence-based.

  5. Design of, and some clinical experience with, a novel optical surface measurement system in radiotherapy

    NASA Astrophysics Data System (ADS)

    Price, G. J.; Marchant, T. E.; Parkhurst, J. M.; Sharrock, P. J.; Whitfield, G.; Moore, C. J.

    2010-04-01

    Optical imaging is becoming more prevalent in image guided radiotherapy as a complementary technology to traditional ionizing radiation based modalities. We present a novel structured light based device that can capture a patient's body surface topology with a large field of view and high spatial and temporal resolution. The system is composed of three cross-calibrated sensor heads that enable 'wrap around' imaging previously unavailable with similar line of sight optical techniques. The system has been installed in a treatment bunker at the Christie Hospital alongside an Elekta linear accelerator equipped with cone beam CT (CBCT) on-board imaging. In this paper we describe the system, focussing on the methodologies required to create a robust and practical device. We show examples of measurements made to ascertain its repeatability and accuracy, and present some initial experiences in using the device for pre-treatment patient set-up.

  6. Amino acid transport system - A substrate predicts the therapeutic effects of particle radiotherapy

    PubMed Central

    Watanabe, Mariko; Suzuki, Hiroyuki; Furusawa, Yoshiya; Arano, Yasushi

    2017-01-01

    L-[methyl-11C]Methionine (11C-Met) is useful for estimating the therapeutic efficacy of particle radiotherapy at early stages of the treatment. Given the short half-life of 11C, the development of longer-lived 18F- and 123I-labeled probes that afford diagnostic information similar to 11C-Met, are being sought. Tumor uptake of 11C-Met is involved in many cellular functions such as amino acid transport System-L, protein synthesis, and transmethylation. Among these processes, since the energy-dependent intracellular functions involved with 11C-Met are more reflective of the radiotherapeutic effects, we evaluated the activity of the amino acid transport System-A as an another energy-dependent cellular function in order to estimate radiotherapeutic effects. In this study, using a carbon-ion beam as the radiation source, the activity of System-A was evaluated by a specific System-A substrate, alpha-[1-14C]-methyl-aminoisobutyric acid (14C-MeAIB). Cellular growth and the accumulation of 14C-MeAIB or 14C-Met were evaluated over time in vitro in cultured human salivary gland (HSG) tumor cells (3-Gy) or in vivo in murine xenografts of HSG tumors (6- or 25-Gy) before and after irradiation with the carbon-ion beam. Post 3-Gy irradiation, in vitro accumulation of 14C-Met and 14C-MeAIB decreased over a 5-day period. In xenografts of HSG tumors in mice, tumor re-growth was observed in vivo on day-10 after a 6-Gy irradiation dose, but no re-growth was detected after the 25-Gy irradiation dose. Consistent with the growth results, the in vivo tumor accumulation of 14C-MeAIB did not decrease after the 6-Gy irradiation dose, whereas a significant decrease was observed after the 25-Gy irradiation dose. These results indicate that the activity of energy dependent System-A transporter may reflect the therapeutic efficacy of carbon-ion radiotherapy and suggests that longer half-life radionuclide-labeled probes for System-A may also provide widely available probes to evaluate the effects

  7. Radiogenomics: A systems biology approach to understanding genetic risk factors for radiotherapy toxicity?

    PubMed

    Herskind, Carsten; Talbot, Christopher J; Kerns, Sarah L; Veldwijk, Marlon R; Rosenstein, Barry S; West, Catharine M L

    2016-11-01

    Adverse reactions in normal tissue after radiotherapy (RT) limit the dose that can be given to tumour cells. Since 80% of individual variation in clinical response is estimated to be caused by patient-related factors, identifying these factors might allow prediction of patients with increased risk of developing severe reactions. While inactivation of cell renewal is considered a major cause of toxicity in early-reacting normal tissues, complex interactions involving multiple cell types, cytokines, and hypoxia seem important for late reactions. Here, we review 'omics' approaches such as screening of genetic polymorphisms or gene expression analysis, and assess the potential of epigenetic factors, posttranslational modification, signal transduction, and metabolism. Furthermore, functional assays have suggested possible associations with clinical risk of adverse reaction. Pathway analysis incorporating different 'omics' approaches may be more efficient in identifying critical pathways than pathway analysis based on single 'omics' data sets. Integrating these pathways with functional assays may be powerful in identifying multiple subgroups of RT patients characterised by different mechanisms. Thus 'omics' and functional approaches may synergise if they are integrated into radiogenomics 'systems biology' to facilitate the goal of individualised radiotherapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. A self-adaptive case-based reasoning system for dose planning in prostate cancer radiotherapy

    SciTech Connect

    Mishra, Nishikant; Petrovic, Sanja; Sundar, Santhanam

    2011-12-15

    Purpose: Prostate cancer is the most common cancer in the male population. Radiotherapy is often used in the treatment for prostate cancer. In radiotherapy treatment, the oncologist makes a trade-off between the risk and benefit of the radiation, i.e., the task is to deliver a high dose to the prostate cancer cells and minimize side effects of the treatment. The aim of our research is to develop a software system that will assist the oncologist in planning new treatments. Methods: A nonlinear case-based reasoning system is developed to capture the expertise and experience of oncologists in treating previous patients. Importance (weights) of different clinical parameters in the dose planning is determined by the oncologist based on their past experience, and is highly subjective. The weights are usually fixed in the system. In this research, the weights are updated automatically each time after generating a treatment plan for a new patient using a group based simulated annealing approach. Results: The developed approach is analyzed on the real data set collected from the Nottingham University Hospitals NHS Trust, City Hospital Campus, UK. Extensive experiments show that the dose plan suggested by the proposed method is coherent with the dose plan prescribed by an experienced oncologist or even better. Conclusions: The developed case-based reasoning system enables the use of knowledge and experience gained by the oncologist in treating new patients. This system may play a vital role to assist the oncologist in making a better decision in less computational time; it utilizes the success rate of the previously treated patients and it can also be used in teaching and training processes.

  9. An automatic dose verification system for adaptive radiotherapy for helical tomotherapy

    NASA Astrophysics Data System (ADS)

    Mo, Xiaohu; Chen, Mingli; Parnell, Donald; Olivera, Gustavo; Galmarini, Daniel; Lu, Weiguo

    2014-03-01

    Purpose: During a typical 5-7 week treatment of external beam radiotherapy, there are potential differences between planned patient's anatomy and positioning, such as patient weight loss, or treatment setup. The discrepancies between planned and delivered doses resulting from these differences could be significant, especially in IMRT where dose distributions tightly conforms to target volumes while avoiding organs-at-risk. We developed an automatic system to monitor delivered dose using daily imaging. Methods: For each treatment, a merged image is generated by registering the daily pre-treatment setup image and planning CT using treatment position information extracted from the Tomotherapy archive. The treatment dose is then computed on this merged image using our in-house convolution-superposition based dose calculator implemented on GPU. The deformation field between merged and planning CT is computed using the Morphon algorithm. The planning structures and treatment doses are subsequently warped for analysis and dose accumulation. All results are saved in DICOM format with private tags and organized in a database. Due to the overwhelming amount of information generated, a customizable tolerance system is used to flag potential treatment errors or significant anatomical changes. A web-based system and a DICOM-RT viewer were developed for reporting and reviewing the results. Results: More than 30 patients were analysed retrospectively. Our in-house dose calculator passed 97% gamma test evaluated with 2% dose difference and 2mm distance-to-agreement compared with Tomotherapy calculated dose, which is considered sufficient for adaptive radiotherapy purposes. Evaluation of the deformable registration through visual inspection showed acceptable and consistent results, except for cases with large or unrealistic deformation. Our automatic flagging system was able to catch significant patient setup errors or anatomical changes. Conclusions: We developed an automatic dose

  10. Neural Stem Cells: Implications for the Conventional Radiotherapy of Central Nervous System Malignancies

    SciTech Connect

    Barani, Igor J.; Benedict, Stanley H.; Lin, Peck-Sun . E-mail: plin@vcu.edu

    2007-06-01

    Advances in basic neuroscience related to neural stem cells and their malignant counterparts are challenging traditional models of central nervous system tumorigenesis and intrinsic brain repair. Neurogenesis persists into adulthood predominantly in two neurogenic centers: subventricular zone and subgranular zone. Subventricular zone is situated adjacent to lateral ventricles and subgranular zone is confined to the dentate gyrus of the hippocampus. Neural stem cells not only self-renew and differentiate along multiple lineages in these regions, but also contribute to intrinsic brain plasticity and repair. Ionizing radiation can depopulate these exquisitely sensitive regions directly or impair in situ neurogenesis by indirect, dose-dependent and inflammation-mediated mechanisms, even at doses <2 Gy. This review discusses the fundamental neural stem cell concepts within the framework of cumulative clinical experience with the treatment of central nervous system malignancies using conventional radiotherapy.

  11. Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source

    SciTech Connect

    Richardson, Susan; Garcia-Ramirez, Jose; Lu Wei; Myerson, Robert J.; Parikh, Parag

    2012-11-15

    Purpose: To present design aspects and acceptance tests performed for clinical implementation of electronic brachytherapy treatment of early stage rectal adenocarcinoma. A dosimetric comparison is made between the historically used Philips RT-50 unit and the newly developed Axxent{sup Registered-Sign} Model S700 electronic brachytherapy source manufactured by Xoft (iCad, Inc.). Methods: Two proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Two custom surface applicators were manufactured by Xoft and were designed to fit and interlock with the proctoscope cones from ESI. Dose rates, half value layers (HVL), and percentage depth dose (PDD) measurements were made with the Xoft system and compared to historical RT-50 data. A description of the patient treatment approach and exposure rates during the procedure is also provided. Results: The electronic brachytherapy system has a lower surface dose rate than the RT-50. The dose rate to water on the surface from the Xoft system is approximately 2.1 Gy/min while the RT-50 is 10-12 Gy/min. However, treatment times with Xoft are still reasonable. The HVLs and PDDs between the two systems were comparable resulting in similar doses to the target and to regions beyond the target. The exposure rate levels around a patient treatment were acceptable. The standard uncertainty in the dose rate to water on the surface is approximately {+-}5.2%. Conclusions: The Philips RT-50 unit is an out-of-date radiotherapy machine that is no longer manufactured with limited replacement parts. The use of a custom-designed proctoscope and Xoft surface applicators allows delivery of a well-established treatment with the ease of a modern radiotherapy device. While the dose rate is lower with the use of Xoft, the treatment times are still reasonable. Additionally, personnel may stand farther away from the Xoft radiation source, thus potentially reducing radiation exposure to the operator and other personnel.

  12. Assessment and evaluation of MV image guidance system performance in radiotherapy.

    PubMed

    Kanakavelu, Nithya; Samuel, E James Jebaseelan

    2015-01-01

    The clinical use of imaging system in image guided radiotherapy (IGRT) necessitates performing periodic quality assurance of the system to be confident in applying corrections for patient set-up errors. We aim to develop and implement a quality assurance (QA) programme for megavoltage (MV) based image guidance system and assess its long term performance for a period of 3 years. Periodic QA tests were performed for the MV planar and cone beam computed tomography (CBCT) imaging system to assess the system safety, mechanical and geometrical accuracy, image quality and dose. The tests were performed using the equipment supplied by the manufacturer along with the image guidance system and using simple methods developed in-house. The test results were compared with expected or baseline values established during commissioning. The safety system was found to be functional. The results of mechanical and geometrical tests were in good agreement with the expected results. The system mechanical positioning was stable and reproducible within ±2 mm accuracy. The image quality and the imaging dose of the planar and CBCT imaging were found to agree with the baseline values and the manufacturer specifications. Throughout the three-year period, all the QA tests were within the specification. The mechanical and geometrical tests are most crucial as they directly affect the patient positioning accuracy. We conclude that the MV image guidance system is efficient to perform IGRT and insist to perform periodic QA tests and calibration for the system.

  13. Infrastructure and equipment for radiation oncology in the Spanish National Health System: analysis of external beam radiotherapy 2015-2020.

    PubMed

    Rodríguez, A; Algara, M; Monge, D; López-Torrecilla, J; Caballero, F; Morera, R; Escó, R; Pérez-Montero, H; Ferrer, C; Lara, P C

    2017-08-03

    Planning for radiation oncology requires reliable estimates of both demand for radiotherapy and availability of technological resources. This study compares radiotherapy resources in the 17 regions of the decentralised Spanish National Health System (SNHS). The Sociedad Española de Oncología Radioterápica (SEOR) performed a cross-sectional survey of all Spanish radiation oncology services (ROS) in 2015. We collected data on SNHS radiotherapy units, recording the year of installation, specific features of linear accelerators (LINACs) and other treatment units, and radiotherapeutic techniques implemented by region. Any machine over 10 years old or lacking a multileaf collimator or portal imaging system was considered obsolete. We performed a k-means clustering analysis using the Hartigan-Wong method to test associations between the gross domestic regional product (GDRP), the number of LINACs per million population and the percentage of LINACs over 10 years old. The SNHS controls 72 (61%) of the 118 Spanish ROS and has 180 LINACs, or 72.5% of the total public and private resources. The mean rate of LINACs per million population is 3.9 for public ROS, and 42% (n = 75) of the public accelerators were obsolete in 2015: 61 due to age and 14 due to technological capability. There was considerable regional variation in terms of the number and technological capacity of radiotherapy units; correlation between GRDP and resource availability was moderate. Despite improvements, new investments are still needed to replace obsolete units and increase access to modern radiotherapy. Regular analysis of ROS in each Spanish region is the only strategy for monitoring progress in radiotherapy capacity.

  14. AutoLock: a semiautomated system for radiotherapy treatment plan quality control.

    PubMed

    Dewhurst, Joseph M; Lowe, Matthew; Hardy, Mark J; Boylan, Christopher J; Whitehurst, Philip; Rowbottom, Carl G

    2015-05-08

    A semiautomated system for radiotherapy treatment plan quality control (QC), named AutoLock, is presented. AutoLock is designed to augment treatment plan QC by automatically checking aspects of treatment plans that are well suited to computational evaluation, whilst summarizing more subjective aspects in the form of a checklist. The treatment plan must pass all automated checks and all checklist items must be acknowledged by the planner as correct before the plan is finalized. Thus AutoLock uniquely integrates automated treatment plan QC, an electronic checklist, and plan finalization. In addition to reducing the potential for the propagation of errors, the integration of AutoLock into the plan finalization workflow has improved efficiency at our center. Detailed audit data are presented, demonstrating that the treatment plan QC rejection rate fell by around a third following the clinical introduction of AutoLock.

  15. Prevention of gross setup errors in radiotherapy with an efficient automatic patient safety system.

    PubMed

    Yan, Guanghua; Mittauer, Kathryn; Huang, Yin; Lu, Bo; Liu, Chihray; Li, Jonathan G

    2013-11-04

    Treatment of the wrong body part due to incorrect setup is among the leading types of errors in radiotherapy. The purpose of this paper is to report an efficient automatic patient safety system (PSS) to prevent gross setup errors. The system consists of a pair of charge-coupled device (CCD) cameras mounted in treatment room, a single infrared reflective marker (IRRM) affixed on patient or immobilization device, and a set of in-house developed software. Patients are CT scanned with a CT BB placed over their surface close to intended treatment site. Coordinates of the CT BB relative to treatment isocenter are used as reference for tracking. The CT BB is replaced with an IRRM before treatment starts. PSS evaluates setup accuracy by comparing real-time IRRM position with reference position. To automate system workflow, PSS synchronizes with the record-and-verify (R&V) system in real time and automatically loads in reference data for patient under treatment. Special IRRMs, which can permanently stick to patient face mask or body mold throughout the course of treatment, were designed to minimize therapist's workload. Accuracy of the system was examined on an anthropomorphic phantom with a designed end-to-end test. Its performance was also evaluated on head and neck as well as abdominalpelvic patients using cone-beam CT (CBCT) as standard. The PSS system achieved a seamless clinic workflow by synchronizing with the R&V system. By permanently mounting specially designed IRRMs on patient immobilization devices, therapist intervention is eliminated or minimized. Overall results showed that the PSS system has sufficient accuracy to catch gross setup errors greater than 1 cm in real time. An efficient automatic PSS with sufficient accuracy has been developed to prevent gross setup errors in radiotherapy. The system can be applied to all treatment sites for independent positioning verification. It can be an ideal complement to complex image-guidance systems due to its

  16. Quality assurance and commissioning of an infrared marker-based patient positioning system for frameless extracranial stereotactic radiotherapy.

    PubMed

    Gupta, Tejpal; Phurailatpam, Reena; Ajay, Mishra; Rajeshri, Pai; Pranshu, Mohindra; Supriya, Chopra

    2007-12-01

    Rapid advancements in imaging technology have led to remarkable improvements in identification and localization of tumors, ushering the era of high-precision techniques in contemporary radiotherapy practice. However, uncertainties in patient set-up and organ motion during a course of fractionated radiotherapy can compromise precision of radiation therapy. Excellent accuracy has been achieved with invasive and non-invasive fixation systems for stereotactic radiotherapy. This report describes the commissioning procedure and Quality Assurance studies done to evaluate the accuracy of isocenter localization by an infrared marker-based positioning system (ExacTrac). The ExacTrac has two infrared cameras that emit and detect infrared rays from reflective markers and construct three-dimensional coordinates of each marker. It detects the difference of the actual isocenter position from the planned isocenter coordinates in three translational (lateral, longitudinal, vertical, or x,y,z axes) and three rotational axes (six degree of freedom). This study performed on a flat and static phantom shows excellent accuracy achieved by the ExacTrac system. The positioning accuracy of ExacTrac (± 1 mm translational displacement and ± 1° rotational errors) can be a valuable tool in implementing frameless extracranial stereotactic radiotherapy. Nevertheless, it needs to be further evaluated on patients with inherent motion and greater positional uncertainty before being adopted in clinical practice.

  17. The CNAO dose delivery system for modulated scanning ion beam radiotherapy.

    PubMed

    Giordanengo, S; Garella, M A; Marchetto, F; Bourhaleb, F; Ciocca, M; Mirandola, A; Monaco, V; Hosseini, M A; Peroni, C; Sacchi, R; Cirio, R; Donetti, M

    2015-01-01

    This paper describes the system for the dose delivery currently used at the Centro Nazionale di Adroterapia Oncologica (CNAO) for ion beam modulated scanning radiotherapy. CNAO Foundation, Istituto Nazionale di Fisica Nucleare and University of Torino have designed, built, and commissioned a dose delivery system (DDS) to monitor and guide ion beams accelerated by a dedicated synchrotron and to distribute the dose with a full 3D scanning technique. Protons and carbon ions are provided for a wide range of energies in order to cover a sizable span of treatment depths. The target volume, segmented in several layers orthogonally to the beam direction, is irradiated by thousands of pencil beams which must be steered and held to the prescribed positions until the prescribed number of particles has been delivered. For the CNAO beam lines, these operations are performed by the DDS. The main components of this system are two independent beam monitoring detectors, called BOX1 and BOX2, interfaced with two control systems performing the tasks of real-time fast and slow control, and connected to the scanning magnets and the beam chopper. As a reaction to any condition leading to a potential hazard, a DDS interlock signal is sent to the patient interlock system which immediately stops the irradiation. The essential tasks and operations performed by the DDS are described following the data flow from the treatment planning system through the end of the treatment delivery. The ability of the DDS to guarantee a safe and accurate treatment was validated during the commissioning phase by means of checks of the charge collection efficiency, gain uniformity of the chambers, and 2D dose distribution homogeneity and stability. A high level of reliability and robustness has been proven by three years of system activity needing rarely more than regular maintenance and working with 100% uptime. Four identical and independent DDS devices have been tested showing comparable performances and

  18. The CNAO dose delivery system for modulated scanning ion beam radiotherapy

    SciTech Connect

    Giordanengo, S.; Marchetto, F.; Garella, M. A.; Donetti, M.; Bourhaleb, F.; Monaco, V.; Hosseini, M. A.; Peroni, C.; Sacchi, R.; Cirio, R.; Ciocca, M.; Mirandola, A.

    2015-01-15

    Purpose: This paper describes the system for the dose delivery currently used at the Centro Nazionale di Adroterapia Oncologica (CNAO) for ion beam modulated scanning radiotherapy. Methods: CNAO Foundation, Istituto Nazionale di Fisica Nucleare and University of Torino have designed, built, and commissioned a dose delivery system (DDS) to monitor and guide ion beams accelerated by a dedicated synchrotron and to distribute the dose with a full 3D scanning technique. Protons and carbon ions are provided for a wide range of energies in order to cover a sizable span of treatment depths. The target volume, segmented in several layers orthogonally to the beam direction, is irradiated by thousands of pencil beams which must be steered and held to the prescribed positions until the prescribed number of particles has been delivered. For the CNAO beam lines, these operations are performed by the DDS. The main components of this system are two independent beam monitoring detectors, called BOX1 and BOX2, interfaced with two control systems performing the tasks of real-time fast and slow control, and connected to the scanning magnets and the beam chopper. As a reaction to any condition leading to a potential hazard, a DDS interlock signal is sent to the patient interlock system which immediately stops the irradiation. The essential tasks and operations performed by the DDS are described following the data flow from the treatment planning system through the end of the treatment delivery. Results: The ability of the DDS to guarantee a safe and accurate treatment was validated during the commissioning phase by means of checks of the charge collection efficiency, gain uniformity of the chambers, and 2D dose distribution homogeneity and stability. A high level of reliability and robustness has been proven by three years of system activity needing rarely more than regular maintenance and working with 100% uptime. Four identical and independent DDS devices have been tested showing

  19. Delayed Effects of Whole Brain Radiotherapy in Germ Cell Tumor Patients With Central Nervous System Metastases

    SciTech Connect

    Doyle, Danielle M. Einhorn, Lawrence H.

    2008-04-01

    Purpose: Central nervous system (CNS) metastases are uncommon in patients with germ cell tumors, with an incidence of 2-3%. CNS metastases have been managed with whole brain radiotherapy (WBRT) and concomitant cisplatin-based combination chemotherapy. Our previous study did not observe serious CNS toxicity (Int J Radiat Oncol Biol Phys 1991;22:17-22). We now report on 5 patients who developed delayed significant CNS toxicity. Patients and Methods: We observed 5 patients with delayed CNS toxicity. The initial diagnosis was between 1981 and 2003. All patients had poor-risk disease according to the International Germ Cell Consensus Collaborative Group criteria. Of the 5 patients, 3 had CNS metastases at diagnosis and 2 developed relapses with CNS metastases. These 5 patients underwent WBRT to 4,000-5,000 cGy in 18-28 fractions concurrently with cisplatin-based chemotherapy. Results: All 5 patients developed delayed symptoms consistent with progressive multifocal leukoencephalopathy. The symptoms included seizures, hemiparesis, cranial neuropathy, headaches, blindness, dementia, and ataxia. The median time from WBRT to CNS symptoms was 72 months (range, 9-228). Head imaging revealed multiple abnormalities consistent with gliosis and diffuse cerebral atrophy. Of the 5 patients, 3 had progressive and 2 stable symptoms. Treatment with surgery and/or steroids had modest benefit. The progressive multifocal leukoencephalopathy resulted in significant debility in all 5 patients, resulting in death (3 patients), loss of work, steroid-induced morbidity, and recurrent hospitalizations. Conclusion: Whole brain radiotherapy is not innocuous in young patients with germ cell tumors and can cause late CNS toxicity.

  20. Dosimetric verification of radiotherapy treatment planning systems in Serbia: national audit.

    PubMed

    Rutonjski, Laza; Petrović, Borislava; Baucal, Milutin; Teodorović, Milan; Cudić, Ozren; Gershkevitsh, Eduard; Izewska, Joanna

    2012-09-12

    Independent external audits play an important role in quality assurance programme in radiation oncology. The audit supported by the IAEA in Serbia was designed to review the whole chain of activities in 3D conformal radiotherapy (3D-CRT) workflow, from patient data acquisition to treatment planning and dose delivery. The audit was based on the IAEA recommendations and focused on dosimetry part of the treatment planning and delivery processes. The audit was conducted in three radiotherapy departments of Serbia. An anthropomorphic phantom was scanned with a computed tomography unit (CT) and treatment plans for eight different test cases involving various beam configurations suggested by the IAEA were prepared on local treatment planning systems (TPSs). The phantom was irradiated following the treatment plans for these test cases and doses in specific points were measured with an ionization chamber. The differences between the measured and calculated doses were reported. The measurements were conducted for different photon beam energies and TPS calculation algorithms. The deviation between the measured and calculated values for all test cases made with advanced algorithms were within the agreement criteria, while the larger deviations were observed for simpler algorithms. The number of measurements with results outside the agreement criteria increased with the increase of the beam energy and decreased with TPS calculation algorithm sophistication. Also, a few errors in the basic dosimetry data in TPS were detected and corrected. The audit helped the users to better understand the operational features and limitations of their TPSs and resulted in increased confidence in dose calculation accuracy using TPSs. The audit results indicated the shortcomings of simpler algorithms for the test cases performed and, therefore the transition to more advanced algorithms is highly desirable.

  1. Proton Radiotherapy for Midline Central Nervous System Lesions: A Class Solution.

    PubMed

    Estabrook, Neil C; McDonald, Mark W; Hoene, Ted A; Bartlett, Greg K; Johnstone, Peter A S; McMullen, Kevin P; Buchsbaum, Jeffrey C

    2015-01-01

    Midline and central lesions of the brain requiring conventional radiotherapy (RT) present complex difficulties in dose avoidance to organs at risk (OAR). In either definitive or adjuvant settings, proper RT coverage of these lesions involves unnecessary treatment of large volumes of normal brain. We propose a class solution for these lesions using proton radiotherapy (PrT). The records of the Indiana University Health Proton Therapy Center were reviewed for patients presenting between January 1, 2005 and October 1, 2013 with midline central nervous system (CNS) lesions. Twenty-four patients were identified. After Institutional Review Board approval was granted, their dosimetry was reviewed for target volume doses and OAR dose avoidance. For these cases, meningiomas were the most common histology (8 cases), and next most prevalent were craniopharyngiomas (6 cases). The others were various different deep midline brain tumors (10 cases). In all cases, fields formed by vertex and/or anterior/posterior superior oblique PrT beams along the midsagittal plane were used to provide coverage with minimal dose to the brain stem or to the cerebral hemispheres. The median prescribed dose to the planning target volume for treating these patients was 54.0 Gy RBE (range 48.6-62.5) with a mean dose of 53.5 Gy RBE. The average of the mean doses to the brain stems using these fields in the 24 plans was 18.4 Gy RBE (range 0.0-44.7). Similarly, the average of the mean doses to the hippocampi was 15.8 Gy RBE (range 0.0-52.6). We consider these patients to be optimally treated with PrT. The use of modified midsagittal PrT schemas allows for the treatment of midline CNS lesions with sparing of most of the uninvolved brain. © 2015 S. Karger AG, Basel.

  2. Development of a deep inspiration breath-hold system for radiotherapy utilizing a laser distance measurer.

    PubMed

    Jensen, Christer Andre; Skottner, Nils; Frengen, Jomar; Lund, Jo-Åsmund

    2017-01-01

    Deep inspiration breath-hold (DIBH) is a technique for treating left-sided breast cancer (LSBC). In modern radiotherapy, one of the main aims is to exclude the heart from the beam aperture with an individualized beam design for LSBC. A deep inhalation will raise the chest wall while the volume of the lungs increase, this will again push the heart away from the breast to be treated. There are a few commercial DIBH systems, both invasive and noninvasive. We present an alternative noninvasive DIBH system based upon an industrial laser distance measurer. This system can be installed in a treatment room at a low cost; it is very easy to use and requires limited amount of training for the personnel and the patient. The system is capable of measuring the position of the chest wall with high frequency and precision in real time. The patient views its breathing curve through video glasses, and gets instructions during the treatment session. The system is well tolerated by test subjects due to its noninvasiveness. © 2016 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  3. Open-Source Medical Devices (OSMD) Design of a Small Animal Radiotherapy System

    NASA Astrophysics Data System (ADS)

    Prajapati, S.; Mackie, T. R.; Jeraj, R.

    2014-03-01

    Open-Source Medical Devices (OSMD) was initiated with the goal of facilitating medical research by developing medical technologies including both hardware and software on an open-source platform. Our first project was to develop an integrated imaging and radiotherapy device for small animals that includes computed tomography (CT), positron emission tomography (PET) and radiation therapy (RT) modalities for which technical specifications were defined in the first OSMD conference held in Madison, Wisconsin, USA in December 2011. This paper specifically focuses on the development of a small animal RT (micro-RT) system by designing a binary micro multileaf collimator (bmMLC) and a small animal treatment planning system (SATPS) to enable intensity modulated RT (IMRT). Both hardware and software projects are currently under development and their current progresses are described. After the development, both bmMLC and TPS will be validated and commissioned for a micro-RT system. Both hardware design and software development will be open-sourced after completion.

  4. Optical eye tracking system for real-time noninvasive tumor localization in external beam radiotherapy

    SciTech Connect

    Via, Riccardo Fassi, Aurora; Fattori, Giovanni; Fontana, Giulia; Pella, Andrea; Tagaste, Barbara; Ciocca, Mario; Riboldi, Marco; Baroni, Guido; Orecchia, Roberto

    2015-05-15

    Purpose: External beam radiotherapy currently represents an important therapeutic strategy for the treatment of intraocular tumors. Accurate target localization and efficient compensation of involuntary eye movements are crucial to avoid deviations in dose distribution with respect to the treatment plan. This paper describes an eye tracking system (ETS) based on noninvasive infrared video imaging. The system was designed for capturing the tridimensional (3D) ocular motion and provides an on-line estimation of intraocular lesions position based on a priori knowledge coming from volumetric imaging. Methods: Eye tracking is performed by localizing cornea and pupil centers on stereo images captured by two calibrated video cameras, exploiting eye reflections produced by infrared illumination. Additionally, torsional eye movements are detected by template matching in the iris region of eye images. This information allows estimating the 3D position and orientation of the eye by means of an eye local reference system. By combining ETS measurements with volumetric imaging for treatment planning [computed tomography (CT) and magnetic resonance (MR)], one is able to map the position of the lesion to be treated in local eye coordinates, thus enabling real-time tumor referencing during treatment setup and irradiation. Experimental tests on an eye phantom and seven healthy subjects were performed to assess ETS tracking accuracy. Results: Measurements on phantom showed an overall median accuracy within 0.16 mm and 0.40° for translations and rotations, respectively. Torsional movements were affected by 0.28° median uncertainty. On healthy subjects, the gaze direction error ranged between 0.19° and 0.82° at a median working distance of 29 cm. The median processing time of the eye tracking algorithm was 18.60 ms, thus allowing eye monitoring up to 50 Hz. Conclusions: A noninvasive ETS prototype was designed to perform real-time target localization and eye movement monitoring

  5. Optical eye tracking system for real-time noninvasive tumor localization in external beam radiotherapy.

    PubMed

    Via, Riccardo; Fassi, Aurora; Fattori, Giovanni; Fontana, Giulia; Pella, Andrea; Tagaste, Barbara; Riboldi, Marco; Ciocca, Mario; Orecchia, Roberto; Baroni, Guido

    2015-05-01

    External beam radiotherapy currently represents an important therapeutic strategy for the treatment of intraocular tumors. Accurate target localization and efficient compensation of involuntary eye movements are crucial to avoid deviations in dose distribution with respect to the treatment plan. This paper describes an eye tracking system (ETS) based on noninvasive infrared video imaging. The system was designed for capturing the tridimensional (3D) ocular motion and provides an on-line estimation of intraocular lesions position based on a priori knowledge coming from volumetric imaging. Eye tracking is performed by localizing cornea and pupil centers on stereo images captured by two calibrated video cameras, exploiting eye reflections produced by infrared illumination. Additionally, torsional eye movements are detected by template matching in the iris region of eye images. This information allows estimating the 3D position and orientation of the eye by means of an eye local reference system. By combining ETS measurements with volumetric imaging for treatment planning [computed tomography (CT) and magnetic resonance (MR)], one is able to map the position of the lesion to be treated in local eye coordinates, thus enabling real-time tumor referencing during treatment setup and irradiation. Experimental tests on an eye phantom and seven healthy subjects were performed to assess ETS tracking accuracy. Measurements on phantom showed an overall median accuracy within 0.16 mm and 0.40° for translations and rotations, respectively. Torsional movements were affected by 0.28° median uncertainty. On healthy subjects, the gaze direction error ranged between 0.19° and 0.82° at a median working distance of 29 cm. The median processing time of the eye tracking algorithm was 18.60 ms, thus allowing eye monitoring up to 50 Hz. A noninvasive ETS prototype was designed to perform real-time target localization and eye movement monitoring during ocular radiotherapy treatments. The

  6. Impact of head and neck radiotherapy on the mechanical behavior of composite resins and adhesive systems: A systematic review.

    PubMed

    Madrid Troconis, Cristhian Camilo; Santos-Silva, Alan Roger; Brandão, Thaís Bianca; Lopes, Marcio Ajudarte; de Goes, Mario Fernando

    2017-08-08

    To analyze the evidence regarding the impact of head and neck radiotherapy (HNRT) on the mechanical behavior of composite resins and adhesive systems. Searches were conducted on PubMed, Embase, Scopus and ISI Web of Science databases using "Radiotherapy", "Composite resins" and "Adhesive systems" as keywords. Selected studies were written in English and assessed the mechanical behavior of composite resins and/or adhesive systems when bonding procedure was conducted before and/or after a maximum radiation dose ≥50Gy, applied under in vitro or in vivo conditions. In total, 115 studies were found but only 16 were included, from which five evaluated the effect of in vitro HNRT on microhardness, wear resistance, diametral tensile and flexural strength of composite resins, showing no significant negative effect in most of reports. Regarding bond strength of adhesive systems, 11 studies were included from which five reported no meaningful negative effect when bonding procedure was conducted before simulated HNRT. Conversely, five studies showed that bond strength diminished when adhesive procedure was done after in vitro radiation therapy. Only two studies about dental adhesion were conducted after in vivo radiotherapy but the results were not conclusive. The mechanical behavior of composite resins and adhesive systems seems not to be affected when in vitro HNRT is applied after bonding procedure. However, bond strength of adhesive systems tends to decrease when simulated radiotherapy is used immediately before bonding procedure. Studies assessing dentin bond strength after in-vivo HNRT were limited and controversial. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  7. Telerobotic system concept for real-time soft-tissue imaging during radiotherapy beam delivery

    SciTech Connect

    Schlosser, Jeffrey; Salisbury, Kenneth; Hristov, Dimitre

    2010-12-15

    Purpose: The curative potential of external beam radiation therapy is critically dependent on having the ability to accurately aim radiation beams at intended targets while avoiding surrounding healthy tissues. However, existing technologies are incapable of real-time, volumetric, soft-tissue imaging during radiation beam delivery, when accurate target tracking is most critical. The authors address this challenge in the development and evaluation of a novel, minimally interfering, telerobotic ultrasound (U.S.) imaging system that can be integrated with existing medical linear accelerators (LINACs) for therapy guidance. Methods: A customized human-safe robotic manipulator was designed and built to control the pressure and pitch of an abdominal U.S. transducer while avoiding LINAC gantry collisions. A haptic device was integrated to remotely control the robotic manipulator motion and U.S. image acquisition outside the LINAC room. The ability of the system to continuously maintain high quality prostate images was evaluated in volunteers over extended time periods. Treatment feasibility was assessed by comparing a clinically deployed prostate treatment plan to an alternative plan in which beam directions were restricted to sectors that did not interfere with the transabdominal U.S. transducer. To demonstrate imaging capability concurrent with delivery, robot performance and U.S. target tracking in a phantom were tested with a 15 MV radiation beam active. Results: Remote image acquisition and maintenance of image quality with the haptic interface was successfully demonstrated over 10 min periods in representative treatment setups of volunteers. Furthermore, the robot's ability to maintain a constant probe force and desired pitch angle was unaffected by the LINAC beam. For a representative prostate patient, the dose-volume histogram (DVH) for a plan with restricted sectors remained virtually identical to the DVH of a clinically deployed plan. With reduced margins, as

  8. Radiotherapy planning of the pelvis using distortion corrected MR images: the removal of system distortions

    NASA Astrophysics Data System (ADS)

    Tanner, S. F.; Finnigan, D. J.; Khoo, V. S.; Mayles, P.; Dearnaley, D. P.; Leach, M. O.

    2000-08-01

    Image distortion is an important consideration in the use of magnetic resonance (MR) images for radiotherapy planning. The distortion is a consequence of system distortion (arising from main magnetic field inhomogeneity and nonlinearities in the applied magnetic field gradients) and of effects arising from the object/patient being imaged. A two-stage protocol has been developed to correct both system- and object-induced distortion in pelvic images which incorporates measures to maintain the quality, accuracy and consistency of the imaging and correction procedures. The first stage of the correction procedure is described here and involves the removal of system distortion. Object- (patient-) induced effects will be described in a subsequent work. Images are acquired with the patient lying on a flat rigid bed, which reproduces treatment conditions. A frame of marker tubes surrounding the patient and attached to the bed provides quality assurance data in each image. System distortions in the three orthogonal planes are mapped using a separate phantom, which fits closely within the quality control frame. Software has been written which automates the measurement and checking of the many marker positions which the test objects generate and which ensures that patient data are acquired using a consistent imaging protocol. Results are presented which show that the scanner and the phantoms used in measuring distortion give highly reproducible results with mean changes of the order of 0.1 mm between repeated measurements of marker positions in the same imaging session. Effective correction for in-plane components of system distortion is demonstrated.

  9. Cavity theory applied to the dosimetry of systemic radiotherapy of bone metastases

    NASA Astrophysics Data System (ADS)

    Breen, Stephen L.; Battista, Jerry J.

    2000-04-01

    A two-component model of an osteoblastic metastatic lesion has been developed to determine the absorbed dose delivered to soft tissue during systemic radiotherapy of osseous metastases. Doses to soft tissue from radioisotopes distributed in bone were calculated using Burlin's general cavity theory. A correction term was used to account for the absence of charged particle equilibrium within the metastatic lesion. Radiation doses for 153 Sm, 186 Re, 89 Sr and 32 P were calculated for several physiologically realistic lesion structures. Burlin's cavity weighting factor was greatest for higher energy isotopes and it decreased as the soft tissue cavity size increased. The correction for the absence of charged particle equilibrium also decreased with soft tissue pathlength, but increased with average bone pathlengths. Doses to soft tissue cavities ranged from 0.1 to 0.2 Gy MBq-1 d-1 for 153 Sm to 0.5 to 0.6 Gy MBq-1 d-1 for 32 P. Using the factors calculated in this work, the dose to soft tissue cavities within bone metastases can be calculated when the dose to adjacent bone has been determined, perhaps by autoradiography or electron paramagnetic resonance dosimetry. The doses calculated with this more accurate model of bone metastases demonstrate errors of 20% to 50% in previous calculations of the average dose to homogeneous metastatic lesions.

  10. Quality assurance for nonradiographic radiotherapy localization and positioning systems: report of Task Group 147.

    PubMed

    Willoughby, Twyla; Lehmann, Joerg; Bencomo, Jose A; Jani, Shirish K; Santanam, Lakshmi; Sethi, Anil; Solberg, Timothy D; Tome, Wolfgang A; Waldron, Timothy J

    2012-04-01

    New technologies continue to be developed to improve the practice of radiation therapy. As several of these technologies have been implemented clinically, the Therapy Committee and the Quality Assurance and Outcomes Improvement Subcommittee of the American Association of Physicists in Medicine commissioned Task Group 147 to review the current nonradiographic technologies used for localization and tracking in radiotherapy. The specific charge of this task group was to make recommendations about the use of nonradiographic methods of localization, specifically; radiofrequency, infrared, laser, and video based patient localization and monitoring systems. The charge of this task group was to review the current use of these technologies and to write quality assurance guidelines for the use of these technologies in the clinical setting. Recommendations include testing of equipment for initial installation as well as ongoing quality assurance. As the equipment included in this task group continues to evolve, both in the type and sophistication of technology and in level of integration with treatment devices, some of the details of how one would conduct such testing will also continue to evolve. This task group, therefore, is focused on providing recommendations on the use of this equipment rather than on the equipment itself, and should be adaptable to each user's situation in helping develop a comprehensive quality assurance program.

  11. Characterization of a computed radiography system for external radiotherapy beam dosimetry

    NASA Astrophysics Data System (ADS)

    Aberle, Christoph; Kapsch, Ralf-Peter

    2016-06-01

    A commercial computed radiography (CR) system was studied as an option for quantitative dosimetry quality assurance of external radiotherapy beams. Following the examination of influencing quantities, practical measurement procedures are discussed. Corrections were derived for image fading, an observed long-term response drift and the image length scale, which was found to be off by up to 2-3%. It is known that energy dependence is important for CR measurements. Therefore, signal-to-dose calibration curves and the energy dependence of the response were studied extensively using multiple photon and electron beam qualities. Doses which yield the same signal vary by up to tens of percent for different beam qualities. Results on the directional response of the plates are presented. It was found that rotations of up to 30° to 40° relative to perpendicular irradiation yield no significant change in response. Finally, the homogeneity of the response over the measurement region was studied for electrons and photons and a correction method is described. In summary, relative dose measurements with uncertainties of a few percent are feasible in regions of constant beam energy.

  12. An update in symptom clusters using the Edmonton Symptom Assessment System in a palliative radiotherapy clinic.

    PubMed

    Ganesh, Vithusha; Zhang, Liying; Chan, Stephanie; Wan, Bo Angela; Drost, Leah; Tsao, May; Danjoux, Cyril; Barnes, Elizabeth; McDonald, Rachel; Rowbottom, Leigha; Zaki, Pearl; Chow, Ronald; Hwang, Matthew K; DeAngelis, Carlo; Lao, Nicholas; Chow, Edward

    2017-05-23

    To identify symptom clusters in advanced cancer patients attending a palliative radiotherapy clinic using the Edmonton Symptom Assessment System (ESAS). Principal component analysis (PCA), exploratory factor analysis (EFA), and hierarchical cluster analysis (HCA) were used to identify symptom clusters among the nine ESAS items using scores from each patient's first visit. ESAS scores from 182 patients were analyzed. The PCA identified three symptom clusters (cluster 1: depression-anxiety-well-being, cluster 2: pain-tiredness-drowsiness, cluster 3: nausea-dyspnea-loss of appetite). The EFA identified two clusters (cluster 1: tiredness-drowsiness-loss of appetite-well-being-pain-nausea-dyspnea, cluster 2: depression-anxiety). The HCA identified three clusters similar to the PCA with an exception of the loss of appetite item being classified under cluster 1 rather than 3. Two to three symptom clusters were identified using three analytical methods, with similar patterns reported in the literature. Particular groups of items co-occurred consistently across all three analyses: depression and anxiety; nausea and dyspnea; as well as pain, tiredness, and drowsiness. Three similar symptom clusters were identified in our patient population using the PCA and HCA; whereas, the EFA produced two clusters: one physical and one psychological cluster. Given the implications of symptom clusters in the management of quality of life, clinicians should be aware of these clusters to aid in the palliative treatment of patients.

  13. FoCa: a modular treatment planning system for proton radiotherapy with research and educational purposes.

    PubMed

    Sánchez-Parcerisa, D; Kondrla, M; Shaindlin, A; Carabe, A

    2014-12-07

    FoCa is an in-house modular treatment planning system, developed entirely in MATLAB, which includes forward dose calculation of proton radiotherapy plans in both active and passive modalities as well as a generic optimization suite for inverse treatment planning. The software has a dual education and research purpose. From the educational point of view, it can be an invaluable teaching tool for educating medical physicists, showing the insights of a treatment planning system from a well-known and widely accessible software platform. From the research point of view, its current and potential uses range from the fast calculation of any physical, radiobiological or clinical quantity in a patient CT geometry, to the development of new treatment modalities not yet available in commercial treatment planning systems. The physical models in FoCa were compared with the commissioning data from our institution and show an excellent agreement in depth dose distributions and longitudinal and transversal fluence profiles for both passive scattering and active scanning modalities. 3D dose distributions in phantom and patient geometries were compared with a commercial treatment planning system, yielding a gamma-index pass rate of above 94% (using FoCa's most accurate algorithm) for all cases considered. Finally, the inverse treatment planning suite was used to produce the first prototype of intensity-modulated, passive-scattered proton therapy, using 13 passive scattering proton fields and multi-leaf modulation to produce a concave dose distribution on a cylindrical solid water phantom without any field-specific compensator.

  14. FoCa: a modular treatment planning system for proton radiotherapy with research and educational purposes

    NASA Astrophysics Data System (ADS)

    Sánchez-Parcerisa, D.; Kondrla, M.; Shaindlin, A.; Carabe, A.

    2014-12-01

    FoCa is an in-house modular treatment planning system, developed entirely in MATLAB, which includes forward dose calculation of proton radiotherapy plans in both active and passive modalities as well as a generic optimization suite for inverse treatment planning. The software has a dual education and research purpose. From the educational point of view, it can be an invaluable teaching tool for educating medical physicists, showing the insights of a treatment planning system from a well-known and widely accessible software platform. From the research point of view, its current and potential uses range from the fast calculation of any physical, radiobiological or clinical quantity in a patient CT geometry, to the development of new treatment modalities not yet available in commercial treatment planning systems. The physical models in FoCa were compared with the commissioning data from our institution and show an excellent agreement in depth dose distributions and longitudinal and transversal fluence profiles for both passive scattering and active scanning modalities. 3D dose distributions in phantom and patient geometries were compared with a commercial treatment planning system, yielding a gamma-index pass rate of above 94% (using FoCa’s most accurate algorithm) for all cases considered. Finally, the inverse treatment planning suite was used to produce the first prototype of intensity-modulated, passive-scattered proton therapy, using 13 passive scattering proton fields and multi-leaf modulation to produce a concave dose distribution on a cylindrical solid water phantom without any field-specific compensator.

  15. Phase I Trial Using Proteasome Inhibitor Bortezomib and Concurrent Temozolomide and Radiotherapy for Central Nervous System Malignancies

    SciTech Connect

    Kubicek, Gregory J.; Werner-Wasik, Maria; Machtay, Mitchell; Mallon, Gayle; Myers, Thomas; Ramirez, Michael; Andrews, David; Curran, Walter J.; Dicker, Adam P.

    2009-06-01

    Purpose: To evaluate the toxicity and response rate of bortezomib with concurrent radiotherapy and temozolomide in the treatment of patients with central nervous system malignancies. Patients and Methods: This open-label, dose-escalation, Phase I clinical study evaluated the safety of three dose levels of intravenously administered bortezomib (0.7, 1.0, and 1.3 mg/m{sup 2}/dose) on Days 1, 4, 8, and 11 of a 21-day cycle, in addition to concurrent radiotherapy and temozolomide at a daily dose of 75 mg/m{sup 2} starting on Day 1. The primary endpoint was dose-limiting toxicity, defined as any Grade 4-5 toxicity or Grade 3 toxicity directly attributable to protocol treatment, requiring hospitalization and/or radiotherapy interruption. The secondary endpoints included feasibility, non-dose-limiting toxicity, and treatment response. Results: A total of 27 patients were enrolled, 23 of whom had high-grade glioma (10 recurrent and 13 newly diagnosed). No dose-limiting toxicities were noted in any dose group, including the highest (1.3 mg/m{sup 2}/dose). The most frequent toxicities were Grade 1 and 2 stomatitis, erythema, and alopecia. All 27 patients were evaluable for response. At a median follow-up of 15.0 months, 9 patients were still alive, with a median survival of 17.4 months for all patients and 15.0 months for patients with high-grade glioma. Conclusion: Bortezomib administered at its typical 'systemic' dose (1.3 mg/m{sup 2}) is well tolerated and safe combined with temozolomide and radiotherapy when used in the treatment of central nervous system malignancies. A Phase II study to characterize efficacy is warranted.

  16. Clinical Evaluation of an Immbolization System for Stereotactic Body Radiotherapy Using Helical Tomotherapy

    SciTech Connect

    Gutierrez, Alonso N.; Stathakis, Sotirios; Crownover, Richard; Esquivel, Carlos; Shi Chengyu; Papanikolaou, Niko

    2011-07-01

    In this study, a clinical evaluation of the Body Pro-Lok{sup TM} System combined with the TomoTherapy megavoltage computed tomography (MVCT) was performed for lung and liver stereotactic body radiotherapy (SBRT) to reduce interfractional setup uncertainty. Twenty patients treated with 3-5 fractions of SBRT were analyzed retrospectively. The Body Pro-Lok{sup TM} system was used in both CT simulation and during patient treatment setup. Patients were immobilized with a vacuum cushion placed posteriorly over the thoracic region, an abdominal compression plate, and a knee and foot sponge. Pretreatment MVCT scans of the TomoTherapy HI-ART II unit were fused with the planning kVCT before delivery of each fraction to determine the interfractional setup error. A total of 84 shifts were analyzed to assess the interfractional setup accuracy. Results showed that the mean interfractional setup errors and standard deviations were -0.9 {+-} 3.1 mm, 1.2 {+-} 5.5 mm, and 6.5 {+-} 2.6 mm for lateral (IEC-X), longitudinal (IEC-Y), and vertical (IEC-Z) variations, respectively. The maximum motion was 17.1 mm in the longitudinal direction. When all 3 translational coordinates were analyzed, a mean composite displacement vector of 8.2 {+-} 2.0 mm (range 4.1-11.7 mm) was obtained for all patients. Based on the findings, image-guided SBRT using the Body Pro-Lok{sup TM} system in conjunction with the MVCT of TomoTherapy is capable of minimizing interfractional setup error and improving treatment accuracy.

  17. Measurement of neutron ambient dose equivalent in carbon-ion radiotherapy with an active scanned delivery system.

    PubMed

    Yonai, S; Furukawa, T; Inaniwa, T

    2014-10-01

    In ion beam radiotherapy, secondary neutrons contribute to an undesired dose outside the target volume, and consequently the increase of secondary cancer risk is a growing concern. In this study, neutron ambient dose equivalents in carbon-ion radiotherapy (CIRT) with an active beam delivery system were measured with a rem meter, WENDI-II, at National Institute of Radiological Sciences. When the same irradiation target was assumed, the measured neutron dose with an active beam was at most ∼15 % of that with a passive beam. This percentage became smaller as larger distances from the iso-centre. Also, when using an active beam delivery system, the neutron dose per treatment dose in CIRT was comparable with that in proton radiotherapy. Finally, it was experimentally demonstrated that the use of an active scanned beam in CIRT can greatly reduce the secondary neutron dose. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Recommendations for Updating T and N Staging Systems for Nasopharyngeal Carcinoma in the Era of Intensity-Modulated Radiotherapy

    PubMed Central

    Liang, Zhong-Guo; Chen, Xiao-Qian; Niu, Zhi-Jie; Chen, Kai-Hua; Li, Ling; Qu, Song; Su, Fang; Zhao, Wei; Li, Ye; Pan, Xin-Bin; Zhu, Xiao-Dong

    2016-01-01

    Objective The aim of this study was to compare the 2008 Chinese and the 7th edition of the American Joint Committee on Cancer (AJCC) staging systems for nasopharyngeal carcinoma and to provide proposals for updating T and N staging systems of the present staging system. Methods Between January 2007 and December 2012, a cohort of 752 patients with biopsy-proven, newly diagnosed, non-metastatic nasopharyngeal carcinoma who were treated with intensity-modulated radiotherapy were retrospectively analysed. Prognoses were compared by T stage, N stage, and clinical stage according to the two staging systems for overall survival (OS), local relapse-free survival (LRFS), and distant metastasis-free survival (DMFS). Results In terms of both the T and N staging systems, the two current staging systems were comparable in predicting OS. The T classification of the 2008 Chinese staging system was better in predicting LRFS, while the N classification of the 7th edition AJCC staging system was superior in predicting DMFS. In the modern era of intensity-modulated radiotherapy, the staging system should be updated by down-staging the current stage T2 to T1, and it might be rational to merge subcategories N1 and N2. Conclusions The two current staging systems each had advantages in predicting prognosis. It seems reasonable to downstage T2 to T1 and to merge N1 and N2. PMID:27973544

  19. Multi-System Verification of Registrations for Image-Guided Radiotherapy in Clinical Trials

    SciTech Connect

    Cui Yunfeng; Galvin, James M.; Straube, William L.; Bosch, Walter R.; Purdy, James A.; Li, X. Allen; Xiao Ying

    2011-09-01

    Purpose: To provide quantitative information on the image registration differences from multiple systems for image-guided radiotherapy (IGRT) credentialing and margin reduction in clinical trials. Methods and Materials: Images and IGRT shift results from three different treatment systems (Tomotherapy Hi-Art, Elekta Synergy, Varian Trilogy) have been sent from various institutions to the Image-Guided Therapy QA Center (ITC) for evaluation for the Radiation Therapy Oncology Group (RTOG) trials. Nine patient datasets (five head-and-neck and four prostate) were included in the comparison, with each patient having 1-4 daily individual IGRT studies. In all cases, daily shifts were re-calculated by re-registration of the planning CT with the daily IGRT data using three independent software systems (MIMvista, FocalSim, VelocityAI). Automatic fusion was used in all calculations. The results were compared with those submitted from institutions. Similar regions of interest (ROIs) and same initial positions were used in registrations for inter-system comparison. Different slice spacings for CBCT sampling and different ROIs for registration were used in some cases to observe the variation of registration due to these factors. Results: For the 54 comparisons with head-and-neck datasets, the absolute values of differences of the registration results between different systems were 2.6 {+-} 2.1 mm (mean {+-} SD; range 0.1-8.6 mm, left-right [LR]), 1.7 {+-} 1.3 mm (0.0-4.9 mm, superior-inferior [SI]), and 1.8 {+-} 1.1 mm (0.1-4.0 mm, anterior-posterior [AP]). For the 66 comparisons in prostate cases, the differences were 1.1 {+-} 1.0 mm (0.0-4.6 mm, LR), 2.1 {+-} 1.7 mm (0.0-6.6 mm, SI), and 2.0 {+-} 1.8 mm (0.1-6.9 mm, AP). The differences caused by the slice spacing variation were relatively small, and the different ROI selections in FocalSim and MIMvista also had limited impact. Conclusion: The extent of differences was reported when different systems were used for image

  20. Technical note: real-time web-based wireless visual guidance system for radiotherapy.

    PubMed

    Lee, Danny; Kim, Siyong; Palta, Jatinder R; Kim, Taeho

    2017-06-01

    Describe a Web-based wireless visual guidance system that mitigates issues associated with hard-wired audio-visual aided patient interactive motion management systems that are cumbersome to use in routine clinical practice. Web-based wireless visual display duplicates an existing visual display of a respiratory-motion management system for visual guidance. The visual display of the existing system is sent to legacy Web clients over a private wireless network, thereby allowing a wireless setting for real-time visual guidance. In this study, active breathing coordinator (ABC) trace was used as an input for visual display, which captured and transmitted to Web clients. Virtual reality goggles require two (left and right eye view) images for visual display. We investigated the performance of Web-based wireless visual guidance by quantifying (1) the network latency of visual displays between an ABC computer display and Web clients of a laptop, an iPad mini 2 and an iPhone 6, and (2) the frame rate of visual display on the Web clients in frames per second (fps). The network latency of visual display between the ABC computer and Web clients was about 100 ms and the frame rate was 14.0 fps (laptop), 9.2 fps (iPad mini 2) and 11.2 fps (iPhone 6). In addition, visual display for virtual reality goggles was successfully shown on the iPhone 6 with 100 ms and 11.2 fps. A high network security was maintained by utilizing the private network configuration. This study demonstrated that a Web-based wireless visual guidance can be a promising technique for clinical motion management systems, which require real-time visual display of their outputs. Based on the results of this study, our approach has the potential to reduce clutter associated with wired-systems, reduce space requirements, and extend the use of medical devices from static usage to interactive and dynamic usage in a radiotherapy treatment vault.

  1. Breast dosimetry in transverse and longitudinal field MRI-Linac radiotherapy systems

    SciTech Connect

    Mahdavi, S. R.; Esmaeeli, A. D.; Pouladian, M.; Sardari, D.; Bagheri, S.; Monfared, A. S.

    2015-02-15

    Purpose: In the framework of developing the integration of a MRI-Linac system, configurations of MRI-Linac units were simulated in order to improve the dose distribution in tangential breast radiotherapy using transverse and longitudinal magnetic field geometries of Lorentz force for both medial and lateral tangential fields. Methods: In this work, the GEANT4 Monte Carlo (MC) code was utilized to compare dose distributions in breast radiotherapy for Linac-MR systems in the transverse and longitudinal geometries within humanoid phantoms across a range of magnetic field strengths of 0.5 and 1.5 T. The dose increment due to scattering from the coils was investigated for both geometries as well. Computed tomography images of two patients were used for MC simulations. One patient had intact breast while the other was mastectomized. In the simulations, planning and methods of chest wall irradiation were similar to the actual clinical planning. Results: In a longitudinal geometry, the magnetic field is shown to restrict the lateral spread of secondary electrons to the lung, heart, and contralateral organs, which reduced the mean dose of the ipsilateral lung and heart by means of 17.2% and 6% at 1.5 T, respectively. The transverse configuration exhibits a significant increase in tissue interface effects, which increased dose buildup in the entrance regions of the lateral and medial tangent beams to the planning target volume (PTV) and improved dose homogeneity within the PTV. The improved relative average homogeneity index for two patients to the PTV at magnetic field strength of 1.5 T with respect to no magnetic field case evaluated was 11.79% and 34.45% in the LRBP and TRBP geometries, respectively. In both geometries, the simulations show significant mean dose reductions in the contralateral breast and chest wall skin, respectively, by a mean of 16.6% and 24.9% at 0.5 T and 17.2% and 28.1% at 1.5 T in the transverse geometry, and 10.56% and 14.6% at 0.5 T and 11.3% and

  2. Breast dosimetry in transverse and longitudinal field MRI-Linac radiotherapy systems.

    PubMed

    Mahdavi, S R; Esmaeeli, A D; Pouladian, M; Monfared, A S; Sardari, D; Bagheri, S

    2015-02-01

    In the framework of developing the integration of a MRI-Linac system, configurations of MRI-Linac units were simulated in order to improve the dose distribution in tangential breast radiotherapy using transverse and longitudinal magnetic field geometries of Lorentz force for both medial and lateral tangential fields. In this work, the geant4 Monte Carlo (MC) code was utilized to compare dose distributions in breast radiotherapy for Linac-MR systems in the transverse and longitudinal geometries within humanoid phantoms across a range of magnetic field strengths of 0.5 and 1.5 T. The dose increment due to scattering from the coils was investigated for both geometries as well. Computed tomography images of two patients were used for MC simulations. One patient had intact breast while the other was mastectomized. In the simulations, planning and methods of chest wall irradiation were similar to the actual clinical planning. In a longitudinal geometry, the magnetic field is shown to restrict the lateral spread of secondary electrons to the lung, heart, and contralateral organs, which reduced the mean dose of the ipsilateral lung and heart by means of 17.2% and 6% at 1.5 T, respectively. The transverse configuration exhibits a significant increase in tissue interface effects, which increased dose buildup in the entrance regions of the lateral and medial tangent beams to the planning target volume (PTV) and improved dose homogeneity within the PTV. The improved relative average homogeneity index for two patients to the PTV at magnetic field strength of 1.5 T with respect to no magnetic field case evaluated was 11.79% and 34.45% in the LRBP and TRBP geometries, respectively. In both geometries, the simulations show significant mean dose reductions in the contralateral breast and chest wall skin, respectively, by a mean of 16.6% and 24.9% at 0.5 T and 17.2% and 28.1% at 1.5 T in the transverse geometry, and 10.56% and 14.6% at 0.5 T and 11.3% and 16.3% at 1.5 T in the

  3. System Integration and Preliminary In-Vivo Experiments of a Robot for Ultrasound Guidance and Monitoring during Radiotherapy

    PubMed Central

    Şen, H. Tutkun; Lediju Bell, Muyinatu A.; Zhang, Yin; Ding, Kai; Wong, John; Iordachita, Iulian; Kazanzides, Peter

    2016-01-01

    We are developing a cooperatively-controlled robot system in which a clinician and robot share control of a 3D ultrasound (US) probe. The goals of the system are to provide guidance for patient setup and real-time target monitoring during fractionated radiotherapy. Currently, there is limited use of realtime US image feedback during radiotherapy for lower abdominal organs and it has not yet been clinically applied for upper abdominal organs. One challenge is that placing an US probe on the patient produces tissue deformation around the target organ, leading to displacement of the target. Our solution is to perform treatment planning on the deformed organ and then to reproduce this deformation during radiotherapy. We therefore introduce a robot system to hold the US probe on the patient. In order to create a consistent deformation, the system records the robot position, contact force, and reference US image during simulation and then introduces virtual constraints (soft virtual fixtures) to guide the clinician to correctly place the probe during the fractionated treatments. Because the robot is under-actuated (5 motorized and 6 passive degrees-of-freedom), the guidance also involves a graphical user interface (adjustment GUI) to achieve the desired probe orientation. This paper presents the integrated system, a proposed clinical workflow, the results of an initial in-vivo canine study with a 3-DOF robot, and the results of phantom experiments with an improved 5-DOF robotic system. The results suggest that the guidance may enable the clinician to more consistently and accurately place the US probe. PMID:27099871

  4. A phantom evaluation of a stereo-vision surface imaging system for radiotherapy patient setup.

    PubMed

    Bert, Christoph; Metheany, Katherine G; Doppke, Karen; Chen, George T Y

    2005-09-01

    External beam irradiation requires precise positioning of the target relative to the treatment planning coordinate system. A three-dimensional (3D) surface imaging system for patient positioning has recently been installed in one of our linear accelerator (linac) rooms. The device utilizes close-range photogrammetry to generate a 3D model of the patient's surface. This geometric model can be made to look like a digital camera image if wrapped with a gray-level image (texture mapping) that shows surface coloration. The system is calibrated to the linac coordinate system and has been designed as a patient setup device. To reproduce patient position in fractionated radiotherapy, the daily patient surface model is registered to a previously recorded reference surface. Using surface registration, the system calculates the rigid-body transformation that minimizes the distance between the treatment and the reference surface models in a region-of-interest (ROI). This transformation is expressed as a set of new couch coordinates at which the patient position best matches with the reference data. If respiratory motion is a concern, the surface can be obtained with a gated acquisition at a specified phase of the respiratory cycle. To analyze the accuracy of the system, we performed several experiments with phantoms to assess stability, alignment accuracy, precision of the gating function, and surface topology. The reproducibility of surface measurements was tested for periods up to 57 h. Each recorded frame was registered to the reference surface to calculate the required couch adjustment. The system stability over this time period was better than 0.5 mm. To measure the accuracy of the system to detect and quantify patient shift relative to a reference image, we compared the shift detected by the surface imaging system with known couch transitions in a phantom study. The maximum standard deviation was 0.75 mm for the three translational degrees of freedom, and less than 0

  5. A phantom evaluation of a stereo-vision surface imaging system for radiotherapy patient setup

    SciTech Connect

    Bert, Christoph; Metheany, Katherine G.; Doppke, Karen; Chen, George T.Y.

    2005-09-15

    External beam irradiation requires precise positioning of the target relative to the treatment planning coordinate system. A three-dimensional (3D) surface imaging system for patient positioning has recently been installed in one of our linear accelerator (linac) rooms. The device utilizes close-range photogrammetry to generate a 3D model of the patient's surface. This geometric model can be made to look like a digital camera image if wrapped with a gray-level image (texture mapping) that shows surface coloration. The system is calibrated to the linac coordinate system and has been designed as a patient setup device. To reproduce patient position in fractionated radiotherapy, the daily patient surface model is registered to a previously recorded reference surface. Using surface registration, the system calculates the rigid-body transformation that minimizes the distance between the treatment and the reference surface models in a region-of-interest (ROI). This transformation is expressed as a set of new couch coordinates at which the patient position best matches with the reference data. If respiratory motion is a concern, the surface can be obtained with a gated acquisition at a specified phase of the respiratory cycle. To analyze the accuracy of the system, we performed several experiments with phantoms to assess stability, alignment accuracy, precision of the gating function, and surface topology. The reproducibility of surface measurements was tested for periods up to 57 h. Each recorded frame was registered to the reference surface to calculate the required couch adjustment. The system stability over this time period was better than 0.5 mm. To measure the accuracy of the system to detect and quantify patient shift relative to a reference image, we compared the shift detected by the surface imaging system with known couch transitions in a phantom study. The maximum standard deviation was 0.75 mm for the three translational degrees of freedom, and less than 0

  6. Tumors of the brain and nervous system after radiotherapy in childhood

    SciTech Connect

    Ron, E.; Modan, B.; Boice, J.D. Jr.; Alfandary, E.; Stovall, M.; Chetrit, A.; Katz, L.

    1988-10-20

    We investigated the relation between radiotherapy in childhood for tinea capitis and the later development of tumors of the brain and nervous system among 10,834 patients treated between 1948 and 1960 in Israel. Benign and malignant tumors were identified from the pathology records of all Israeli hospitals and from Israeli national cancer and death registries. Doses of radiation to the neural tissue were retrospectively estimated for each patient (mean, 1.5 Gy). Sixty neural tumors developed in the patients exposed as children, and the 30-year cumulative risk (+/- SE) was 0.8 +/- 0.2 percent. The incidence of tumors was 1.8 per 10,000 persons per year. The estimated relative risk as compared with that for 10,834 matched general-population controls and 5392 siblings who had not been irradiated was 6.9 (95 percent confidence interval, 4.1 to 11.6) for all tumors and 8.4 (confidence interval, 4.8 to 14.8) when the analysis was restricted to neural tumors of the head and neck. Increased risks were apparent for meningiomas (relative risk, 9.5; n = 19), gliomas (relative risk, 2.6; n = 7), nerve-sheath tumors (relative risk, 18.8; n = 25), and other neural tumors (relative risk, 3.4; n = 9). A strong dose--response relation was found, with the relative risk approaching 20 after estimated doses of approximately 2.5 Gy. Our study confirms that radiation doses on the order of 1 to 2 Gy can significantly increase the risk of neural tumors.

  7. Proton Radiotherapy for Pediatric Central Nervous System Germ Cell Tumors: Early Clinical Outcomes

    SciTech Connect

    MacDonald, Shannon M.; Trofimov, Alexei; Safai, Sairos; Adams, Judith; Fullerton, Barbara; Ebb, David; Tarbell, Nancy J.; Yock, Torunn I.

    2011-01-01

    Purpose: To report early clinical outcomes for children with central nervous system (CNS) germ cell tumors treated with protons; to compare dose distributions for intensity-modulated photon radiotherapy (IMRT), three-dimensional conformal proton radiation (3D-CPT), and intensity-modulated proton therapy with pencil beam scanning (IMPT) for whole-ventricular irradiation with and without an involved-field boost. Methods and Materials: All children with CNS germinoma or nongerminomatous germ cell tumor who received treatment at the Massachusetts General Hospital between 1998 and 2007 were included in this study. The IMRT, 3D-CPT, and IMPT plans were generated and compared for a representative case. Results: Twenty-two patients were treated with 3D-CPT. At a median follow-up of 28 months, there were no CNS recurrences; 1 patient had a recurrence outside the CNS. Local control, progression-free survival, and overall survival rates were 100%, 95%, and 100%, respectively. Comparable tumor volume coverage was achieved with IMRT, 3D-CPT, and IMPT. Substantial normal tissue sparing was seen with any form of proton therapy as compared with IMRT. The use of IMPT may yield additional sparing of the brain and temporal lobes. Conclusions: Preliminary disease control with proton therapy compares favorably to the literature. Dosimetric comparisons demonstrate the advantage of proton radiation over IMRT for whole-ventricle radiation. Superior dose distributions were accomplished with fewer beam angles utilizing 3D-CPT and scanned protons. Intensity-modulated proton therapy with pencil beam scanning may improve dose distribution as compared with 3D-CPT for this treatment.

  8. Radiotherapy for brain metastases near the end of life in an integrated health care system.

    PubMed

    Ryoo, Joan J; Batech, Michael; Zheng, Chengyi; Kim, Raymond W; Gould, Michael K; Kagan, A Robert; Lien, Winston W

    2017-08-01

    To examine radiotherapy (RT) patterns-of-care and utilization at the end of life (EOL) among non-small cell lung cancer (NSCLC) patients with brain metastasis (BrM) in an integrated health care system. Central tumor registry identified 5,133 patients diagnosed with NSCLC from 2007-2011. BrM were determined by imaging. Patient and clinical characteristics were obtained by chart abstraction. In addition to abstracted variables, graded prognostic assessment (GPA) score of 0-1 was derived by collected data and tested as a predictor of death within 14 or 30 days of RT. On NSCLC presentation, 10% harbored BrM while 7% developed BrM thereafter. Of 900 BrM patients, 15% were not referred for RT, with median time to death of 21 days. Median time to death for 5% not recommended RT was 48 days. Among those receiving brain RT, 11.9% died within 14 days and 23.3% (cumulatively) died within 30 days of treatment. Over 50% with GPA score 0-1 received RT, 11% within 14 days and 21% within 30 days of death; median survival of GPA score 0-1 patients was 49 days. GPA score 0-1 independently predicted for death within 30 days of RT receipt. BrM are common in NSCLC, and most patients are referred for brain RT. A surprising proportion of patients received treatment near the EOL, as 23% died within 30 days of RT. GPA score of 0-1 predicted for death within 30 days of treatment. RT referral, recommendation, and timing should be better tailored to life expectancy, and additional benchmarks for quality of care are needed.

  9. An experimental study on cervix cancer with combination of HSV-TK/GCV suicide gene therapy system and 60Co radiotherapy

    PubMed Central

    2010-01-01

    Background To evaluate the killing effect of HSV-TK/GCV suicide gene therapy system combined with 60Co radiotherapy on human cervical cancer Hela cell line in vitro and in vivo, and to explore the radiosensitization by HSV-TK/GCV system. Methods HSV-TK/GCV suicide gene therapy system and 60Co radiotherapy were used separately or in combination on human cervical cancer Hela cell line in vitro and in vivo to compare their effects. Colony formation test and the rate of radiosensitization effect (E/O) were employed to observed the radiosensitization by HSV-TK/GCV system. Results HSV-TK/GCV suicide gene therapy system had strong therapeutic effects on Hela cells in vitro and in vivo (the inhibition rates were 45.8% and 39.5%, respectively), moreover, the combined administration of gene therapy and radiotherapy had stronger therapeutic effects in vitro and in vivo (the inhibition rate was 87.5% in vitro, and the inhibition rate was 87.9% in vivo) (P < 0.01). The inhibition rate by radiotherapy alone was 42.4% in vitro and 35.8% in vivo. The sensitivity of combined therapy to radiotherapy increased more than that of therapy alone, the ability of colony formation decreased (P < 0.01). The rate of radiosensitivity effect (E/O) was 3.17(> 1.4), indicating HSV-TK/GCV system could exert a sensitizing effect on 60Co radiotherapy of the transplanted human cervical cancer cell in nude mice. Conclusion HSV-TK/GCV system had radiosensitization. Gene therapy combined with radiotherapy may be a good supplementary method for cervix cancer synthetic treatment. PMID:21054886

  10. Designing the safety of healthcare. Participation of ergonomics to the design of cooperative systems in radiotherapy.

    PubMed

    Munoz, Maria Isabel; Bouldi, Nadia; Barcellini, Flore; Nascimento, Adelaide

    2012-01-01

    This communication deals with the involvement of ergonomists in a research-action design process of a software platform in radiotherapy. The goal of the design project is to enhance patient safety by designing a workflow software that supports cooperation between professionals producing treatment in radiotherapy. The general framework of our approach is the ergonomics management of a design process, which is based in activity analysis and grounded in participatory design. Two fields are concerned by the present action: a design environment which is a participatory design process that involves software designers, caregivers as future users and ergonomists; and a reference real work setting in radiotherapy. Observations, semi-structured interviews and participatory workshops allow the characterization of activity in radiotherapy dealing with uses of cooperative tools, sources of variability and non-ruled strategies to manage the variability of the situations. This production of knowledge about work searches to enhance the articulation between technocentric and anthropocentric approaches, and helps in clarifying design requirements. An issue of this research-action is to develop a framework to define the parameters of the workflow tool, and the conditions of its deployment.

  11. Monte Carlo simulation of a compact microbeam radiotherapy system based on carbon nanotube field emission technology.

    PubMed

    Schreiber, Eric C; Chang, Sha X

    2012-08-01

    Microbeam radiation therapy (MRT) is an experimental radiotherapy technique that has shown potent antitumor effects with minimal damage to normal tissue in animal studies. This unique form of radiation is currently only produced in a few large synchrotron accelerator research facilities in the world. To promote widespread translational research on this promising treatment technology we have proposed and are in the initial development stages of a compact MRT system that is based on carbon nanotube field emission x-ray technology. We report on a Monte Carlo based feasibility study of the compact MRT system design. Monte Carlo calculations were performed using EGSnrc-based codes. The proposed small animal research MRT device design includes carbon nanotube cathodes shaped to match the corresponding MRT collimator apertures, a common reflection anode with filter, and a MRT collimator. Each collimator aperture is sized to deliver a beam width ranging from 30 to 200 μm at 18.6 cm source-to-axis distance. Design parameters studied with Monte Carlo include electron energy, cathode design, anode angle, filtration, and collimator design. Calculations were performed for single and multibeam configurations. Increasing the energy from 100 kVp to 160 kVp increased the photon fluence through the collimator by a factor of 1.7. Both energies produced a largely uniform fluence along the long dimension of the microbeam, with 5% decreases in intensity near the edges. The isocentric dose rate for 160 kVp was calculated to be 700 Gy∕min∕A in the center of a 3 cm diameter target. Scatter contributions resulting from collimator size were found to produce only small (<7%) changes in the dose rate for field widths greater than 50 μm. Dose vs depth was weakly dependent on filtration material. The peak-to-valley ratio varied from 10 to 100 as the separation between adjacent microbeams varies from 150 to 1000 μm. Monte Carlo simulations demonstrate that the proposed compact MRT system

  12. Monte Carlo simulation of a compact microbeam radiotherapy system based on carbon nanotube field emission technology

    PubMed Central

    Schreiber, Eric C.; Chang, Sha X.

    2012-01-01

    Purpose: Microbeam radiation therapy (MRT) is an experimental radiotherapy technique that has shown potent antitumor effects with minimal damage to normal tissue in animal studies. This unique form of radiation is currently only produced in a few large synchrotron accelerator research facilities in the world. To promote widespread translational research on this promising treatment technology we have proposed and are in the initial development stages of a compact MRT system that is based on carbon nanotube field emission x-ray technology. We report on a Monte Carlo based feasibility study of the compact MRT system design. Methods: Monte Carlo calculations were performed using EGSnrc-based codes. The proposed small animal research MRT device design includes carbon nanotube cathodes shaped to match the corresponding MRT collimator apertures, a common reflection anode with filter, and a MRT collimator. Each collimator aperture is sized to deliver a beam width ranging from 30 to 200 μm at 18.6 cm source-to-axis distance. Design parameters studied with Monte Carlo include electron energy, cathode design, anode angle, filtration, and collimator design. Calculations were performed for single and multibeam configurations. Results: Increasing the energy from 100 kVp to 160 kVp increased the photon fluence through the collimator by a factor of 1.7. Both energies produced a largely uniform fluence along the long dimension of the microbeam, with 5% decreases in intensity near the edges. The isocentric dose rate for 160 kVp was calculated to be 700 Gy/min/A in the center of a 3 cm diameter target. Scatter contributions resulting from collimator size were found to produce only small (<7%) changes in the dose rate for field widths greater than 50 μm. Dose vs depth was weakly dependent on filtration material. The peak-to-valley ratio varied from 10 to 100 as the separation between adjacent microbeams varies from 150 to 1000 μm. Conclusions: Monte Carlo simulations demonstrate

  13. Phase I Trial Using Patupilone (Epothilone B) and Concurrent Radiotherapy for Central Nervous System Malignancies

    SciTech Connect

    Fogh, Shannon; Machtay, Mitchell; Werner-Wasik, Maria; Curran, Walter J.; Bonanni, Roseann; Axelrod, Rita; Andrews, David; Dicker, Adam P.

    2010-07-15

    Purpose: Based on preclinical data indicating the radiosensitizing potential of epothilone B, the present study was designed to evaluate the toxicity and response rate of patupilone, an epothilone B, with concurrent radiotherapy (RT) for the treatment of central nervous system malignancies. Methods and Materials: The present Phase I study evaluated the toxicities associated with patupilone combined with RT to establish the maximal tolerated dose. Eligible patients had recurrent gliomas (n = 10) primary (n = 5) or metastatic (n = 17) brain tumors. Dose escalation occurred if no dose-limiting toxicities, defined as any Grade 4-5 toxicity or Grade 3 toxicity requiring hospitalization, occurred during treatment. Results: Of 14 patients, 5 were treated with weekly patupilone at 1.5 mg/m{sup 2}, 4 at 2.0 mg/m{sup 2}, 4 at 2.5 mg/m{sup 2}, and 1 at 4 mg/m{sup 2}. Of 18 patients, 7 were treated in the 6-mg/m{sup 2} group, 6 in the 8-mg/m{sup 2} group, and 5 in the 10-mg/m{sup 2} group. Primary central nervous system malignancies received RT to a median dose of 60 Gy. Central nervous system metastases received whole brain RT to a median dose of 37.4 Gy, and patients with recurrent gliomas underwent stereotactic RT to a median dose of 37.5 Gy. One dose-limiting toxicity (pneumonia) was observed in group receiving 8-mg/m{sup 2} every 3 weeks. At the subsequent dose level (10 mg/m{sup 2}), two Grade 4 dose-limiting toxicities occurred (renal failure and pulmonary hemorrhage); thus, 8 mg/m{sup 2} every 3 weeks was the maximal tolerated dose and the recommended Phase II dose. Conclusion: Combined with a variety of radiation doses and fractionation schedules, concurrent patupilone was well tolerated and safe, with a maximal tolerated dose of 8 mg/m{sup 2} every 3 weeks.

  14. Commissioning of a conformal irradiation system for heavy-ion radiotherapy using a layer-stacking method

    SciTech Connect

    Kanai, Tatsuaki; Kanematsu, Nobuyuki; Minohara, Shinichi; Komori, Masataka; Torikoshi, Masami; Asakura, Hiroshi; Ikeda, Noritoshi; Uno, Takayuki; Takei, Yuka

    2006-08-15

    The commissioning of conformal radiotherapy system using heavy-ion beams at the Heavy Ion Medical Accelerator in Chiba (HIMAC) is described in detail. The system at HIMAC was upgraded for a clinical trial using a new technique: large spot uniform scanning with conformal layer stacking. The system was developed to localize the irradiation dose to the target volume more effectively than with the old system. With the present passive irradiation method using a ridge filter, a scatterer, a pair of wobbler magnets, and a multileaf collimator, the width of the spread-out Bragg peak (SOBP) in the radiation field could not be changed. With dynamic control of the beam-modifying devices during irradiation, a more conformal radiotherapy could be achieved. In order to safely perform treatments with this conformal therapy, the moving devices should be watched during irradiation and the synchronousness among the devices should be verified. This system, which has to be safe for patient irradiations, was constructed and tested for safety and for the quality of the dose localization realized. Through these commissioning tests, we were successfully able to prepare the conformal technique using layer stacking for patients. Subsequent to commissioning the technique has been applied to patients in clinical trials.

  15. SU-E-T-469: Implementation of VAs Web-Based Radiotherapy Incident Reporting and Analysis System (RIRAS)

    SciTech Connect

    Kapoor, R; Palta, J; Hagan, M; Malik, G

    2015-06-15

    Purpose: This Web-based Radiotherapy Incident Reporting and Analysis System (RIRAS) is a tool to improve quality of care for radiation therapy patients. This system is an important facet of continuing effort by our community to maintain and improve safety of radiotherapy.Material and Methods: VA’s National Radiation Oncology Program office has embarked on a program to electronically collect adverse events and good-catch data of radiation treatment of over 25,000 veterans treated with radiotherapy annually. This VA-Intranet based software design has made use of dataset taxonomies and data dictionaries defined in AAPM/ASTRO reports on error reporting. We used proven industrial and medical event reporting techniques to avoid several common problems faced in effective data collection such as incomplete data due to data entry fatigue by the reporters, missing data due to data difficult to obtain or not familiar to most reporters, missing reports due to fear of reprisal etc. This system encompasses the entire feedback loop of reporting an incident, analyzing it for salient details, and developing interventions to prevent it from happening again. The analysis reports with corrective, learning actions are shared with the reporter/facility and made public to the community (after deidentification) as part of the learning process. Results: Till date 50 incident/good catches have been reported in RIRAS and we have completed analysis on 100% of these reports. This is done due to the fact that each reported incidents is investigated and a complete analysis/patient-safety-work-product report is generated by radiation oncology domain-experts. Conclusions Because of the completeness of the data, the system has enabled us to analyze process steps and track trends of major errors which in the future will lead to implementing system wide process improvement steps and safe standard operating procedures for each radiotherapy treatment modality/technique and fulfills our goal of

  16. Efficacy of stereotactic radiotherapy for brain metastases using dynamic jaws technology in the helical tomotherapy system

    PubMed Central

    Hayashi, Akihiro; Manabe, Yoshihiko; Sugie, Chikao; Takaoka, Taiki; Yanagi, Takeshi; Oguri, Tetsuya; Matsuo, Masayuki; Mori, Yoshimasa; Shibamoto, Yuta

    2016-01-01

    Objective: Dynamic jaws (DJ) are expected to be useful in stereotactic radiotherapy (SRT) for brain metastases (BM). The efficacy and optimal dose fractionation were investigated. Methods: In a planning study, 63 treatment plans were generated for the following 3 conditions: 1.0-cm fixed jaws (FJ), 2.5-cm FJ and 2.5-cm DJ. In a clinical study, 30 Gy/3 fr, 35 Gy/5 fr or 37.5 Gy/5 fr were prescribed depending on tumour size. Clinical results of groups treated with 2.5-cm DJ plans and 1.0-cm FJ were compared. Results: In the planning study, the treatment times in 2.5-cm DJ and FJ plans were less than that in 1.0-cm FJ plans (p < 0.001). The brain doses in 1.0-cm FJ plans and 2.5-cm DJ plans were smaller than those in 2.5-cm FJ plans (p < 0.05). In the clinical study, 34 patients with 68 BM were treated with SRT. Of those, 15 patients with 34 BM were treated with 2.5-cm DJ plans and 19 patients with 34 BM were treated with 1.0-cm FJ plans. The overall survival and local tumour control (LC) rates were 52 and 93% at 12 months, respectively. The DJ system achieved favourable LC and 29% shorter treatment time compared with the FJ system (p < 0.001). Grade 2 or 3 necrosis occurred more frequently in patients with 15 cc or larger tumour volumes (p = 0.05). Conclusion: DJ technology enables treatment time to be reduced without worsening the dose distribution and clinical efficacy. The prescribed doses in this study may be acceptable for patients with small tumour volumes. Advances in knowledge: DJ technology enables treatment time to be reduced without worsening the dose. PMID:27556639

  17. Energy Dependence of Measured CT Numbers on Substituted Materials Used for CT Number Calibration of Radiotherapy Treatment Planning Systems

    PubMed Central

    Mahmoudi, Reza; Jabbari, Nasrollah; aghdasi, Mehdi; Khalkhali, Hamid Reza

    2016-01-01

    Introduction For accurate dose calculations, it is necessary to provide a correct relationship between the CT numbers and electron density in radiotherapy treatment planning systems (TPSs). The purpose of this study was to investigate the energy dependence of measured CT numbers on substituted materials used for CT number calibration of radiotherapy TPSs and the resulting errors in the treatment planning calculation doses. Materials and Methods In this study, we designed a cylindrical water phantom with different materials used as tissue equivalent materials for the simulation of tissues and obtaining the related CT numbers. For evaluating the effect of CT number variations of substituted materials due to energy changing of scanner (kVp) on the dose calculation of TPS, the slices of the scanned phantom at three kVp's were imported into the desired TPSs (MIRS and CorePLAN). Dose calculations were performed on two TPSs. Results The mean absolute percentage differences between the CT numbers of CT scanner and two treatment planning systems for all the samples were 3.22%±2.57% for CorePLAN and 2.88%±2.11% for MIRS. It was also found that the maximum absolute percentage difference between all of the calculated doses from each photon beam of linac (6 and 15 MV) at three kVp's was less than 1.2%. Discussion The present study revealed that, for the materials with effective low atomic number, the mean CT number increased with increasing energy, which was opposite for the materials with an effective high atomic number. We concluded that the tissue substitute materials had a different behavior in the energy ranges from 80 to 130 kVp. So, it is necessary to consider the energy dependence of the substitute materials used for the measurement or calibration of CT number for radiotherapy treatment planning systems. PMID:27391672

  18. Assessment of dosimetric impact of system specific geometric distortion in an MRI only based radiotherapy workflow for prostate

    NASA Astrophysics Data System (ADS)

    Gustafsson, C.; Nordström, F.; Persson, E.; Brynolfsson, J.; Olsson, L. E.

    2017-04-01

    Dosimetric errors in a magnetic resonance imaging (MRI) only radiotherapy workflow may be caused by system specific geometric distortion from MRI. The aim of this study was to evaluate the impact on planned dose distribution and delineated structures for prostate patients, originating from this distortion. A method was developed, in which computer tomography (CT) images were distorted using the MRI distortion field. The displacement map for an optimized MRI treatment planning sequence was measured using a dedicated phantom in a 3 T MRI system. To simulate the distortion aspects of a synthetic CT (electron density derived from MR images), the displacement map was applied to CT images, referred to as distorted CT images. A volumetric modulated arc prostate treatment plan was applied to the original CT and the distorted CT, creating a reference and a distorted CT dose distribution. By applying the inverse of the displacement map to the distorted CT dose distribution, a dose distribution in the same geometry as the original CT images was created. For 10 prostate cancer patients, the dose difference between the reference dose distribution and inverse distorted CT dose distribution was analyzed in isodose level bins. The mean magnitude of the geometric distortion was 1.97 mm for the radial distance of 200-250 mm from isocenter. The mean percentage dose differences for all isodose level bins, were  ⩽0.02% and the radiotherapy structure mean volume deviations were  <0.2%. The method developed can quantify the dosimetric effects of MRI system specific distortion in a prostate MRI only radiotherapy workflow, separated from dosimetric effects originating from synthetic CT generation. No clinically relevant dose difference or structure deformation was found when 3D distortion correction and high acquisition bandwidth was used. The method could be used for any MRI sequence together with any anatomy of interest.

  19. Impact of intense systemic therapy and improved survival on the use of palliative radiotherapy in patients with bone metastases from prostate cancer

    PubMed Central

    Nieder, Carsten; Haukland, Ellinor; Mannsåker, Bård; Norum, Jan

    2016-01-01

    More effective drugs may reduce the requirement for palliative external beam radiotherapy for bony target volumes; however, living with metastases for prolonged periods of time may result in more frequent episodes of bone pain or serious skeletal-related events. The purpose of the present study was to evaluate how recent advances in systemic therapy impact radiotherapy utilization. A retrospective analysis of a comprehensive regional database was performed. All oncology care in this region was provided by only one center, assuring complete data. Patients that had succumbed between June 1, 2004 and June 1, 2015 were included. For all 236 patients, the median age at diagnosis of bone metastases was 75 years and median overall survival was 20 months. More intense systemic therapy was associated with a significantly longer survival time. Only 69 patients (29%) did not receive palliative radiotherapy for bony target volumes, whilst 1 course was given to 101 patients (43%), 2 courses to 34 patients (14%) and >2 courses to 32 patients (14%). Radiotherapy was used more frequently in younger patients, those with spinal cord compressions or pathological fractures, and those treated with intense and long-standing systemic therapy. Radiotherapy utilization increased with survival time. For 100 poor-prognosis patients that succumbed within 12 months, 57 courses of palliative radiotherapy were administered, whilst 100 patients that survived for 12–24 months were administered 114 courses (24–36 months, 148 courses). In conclusion, the use of palliative radiotherapy did not decrease when more effective systemic therapy was administered. However, provided that only 5% of patients received radionuclide treatment, additional studies in other populations are required. PMID:27698881

  20. Clinical benefits of new immobilization system for hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma by helical tomotherapy.

    PubMed

    Hu, Yong; Zhou, Yong-Kang; Chen, Yi-Xing; Shi, Shi-Ming; Zeng, Zhao-Chong

    2017-01-01

    A comprehensive clinical evaluation was conducted, assessing the Body Pro-Lok immobilization and positioning system to facilitate hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma (HCC), using helical tomotherapy to improve treatment precision. Clinical applications of the Body Pro-Lok system were investigated (as above) in terms of interfractional and intrafractional setup errors and compressive abdominal breath control. To assess interfractional setup errors, a total of 42 patients who were given 5 to 20 fractions of helical tomotherapy for intrahepatic HCC were analyzed. Overall, 15 patients were immobilized using simple vacuum cushion (group A), and the Body Pro-Lok system was used in 27 patients (group B), performing megavoltage computed tomography (MVCT) scans 196 times and 435 times, respectively. Pretreatment MVCT scans were registered to the planning kilovoltage computed tomography (KVCT) for error determination, and group comparisons were made. To establish intrafractional setup errors, 17 patients with intrahepatic HCC were selected at random for immobilization by Body Pro-Lok system, undergoing MVCT scans after helical tomotherapy every week. A total of 46 MVCT re-scans were analyzed for this purpose. In researching breath control, 12 patients, randomly selected, were immobilized by Body Pro-Lok system and subjected to 2-phase 4-dimensional CT (4DCT) scans, with compressive abdominal control or in freely breathing states, respectively. Respiratory-induced liver motion was then compared. Mean interfractional setup errors were as follows: (1) group A: X, 2.97 ± 2.47mm; Y, 4.85 ± 4.04mm; and Z, 3.77 ± 3.21mm; pitch, 0.66 ± 0.62°; roll, 1.09 ± 1.06°; and yaw, 0.85 ± 0.82°; and (2) group B: X, 2.23 ± 1.79mm; Y, 4.10 ± 3.36mm; and Z, 1.67 ± 1.91mm; pitch, 0.45 ± 0.38°; roll, 0.77 ± 0.63°; and yaw, 0.52 ± 0.49°. Between-group differences were statistically significant in 6 directions (p < 0.05). Mean intrafractional setup

  1. Intrafractional prostate motion during external beam radiotherapy monitored by a real-time target localization system.

    PubMed

    Tong, Xu; Chen, Xiaoming; Li, Jinsheng; Xu, Qianqian; Lin, Mu-Han; Chen, Lili; Price, Robert A; Ma, Chang-Ming

    2015-03-08

    This paper investigates the clinical significance of real-time monitoring of intrafractional prostate motion during external beam radiotherapy using a commercial 4D localization system. Intrafractional prostate motion was tracked during 8,660 treatment fractions for 236 patients. The following statistics were analyzed: 1) the percentage of fractions in which the prostate shifted 2-7 mm for a certain duration; 2) the proportion of the entire tracking time during which the prostate shifted 2-7mm; and 3) the proportion of each minute in which the shift exceeded 2-7 mm. The ten patients exhibiting maximum intrafractional-motion patterns were analyzed separately. Our results showed that the percentage of fractions in which the prostate shifted by > 2, 3, 5, and 7 mm off the baseline in any direction for > 30 s was 56.8%, 27.2%, 4.6%, and 0.7% for intact prostate and 68.7%, 35.6%, 10.1%, and 1.8% for postprostatectomy patients, respectively. For the ten patients, these percentages were 91.3%, 72.4%, 36.3%, and 6%, respectively. The percentage of tracking time during which the prostate shifted > 2, 3, 5, and 7 mm was 27.8%, 10.7%, 1.6%, and 0.3%, respectively, and it was 56.2%, 33.7%, 11.2%, and 2.1%, respectively, for the ten patients. The percentage of tracking time for a > 3 mm posterior motion was four to five times higher than that in other directions. For treatments completed in 5 min (VMAT) and 10 min (IMRT), the proportion for the prostate to shift by > 3mm was 4% and 12%, respectively. Although intrafractional prostate motion was generally small, caution should be taken for patients who exhibit frequent large intrafractional motion. For those patients, adjustment of patient positioning may be necessary or a larger treatment margin may be used. After the initial alignment, the likelihood of prostate motion increases with time. Therefore, it is favorable to use advanced techniques (e.g., VMAT) that require less delivery time in order to reduce the treatment

  2. Toll-like receptor 4-dependent contribution of the immune system to anticancer chemotherapy and radiotherapy.

    PubMed

    Apetoh, Lionel; Ghiringhelli, François; Tesniere, Antoine; Obeid, Michel; Ortiz, Carla; Criollo, Alfredo; Mignot, Grégoire; Maiuri, M Chiara; Ullrich, Evelyn; Saulnier, Patrick; Yang, Huan; Amigorena, Sebastian; Ryffel, Bernard; Barrat, Franck J; Saftig, Paul; Levi, Francis; Lidereau, Rosette; Nogues, Catherine; Mira, Jean-Paul; Chompret, Agnès; Joulin, Virginie; Clavel-Chapelon, Françoise; Bourhis, Jean; André, Fabrice; Delaloge, Suzette; Tursz, Thomas; Kroemer, Guido; Zitvogel, Laurence

    2007-09-01

    Conventional cancer treatments rely on radiotherapy and chemotherapy. Such treatments supposedly mediate their effects via the direct elimination of tumor cells. Here we show that the success of some protocols for anticancer therapy depends on innate and adaptive antitumor immune responses. We describe in both mice and humans a previously unrecognized pathway for the activation of tumor antigen-specific T-cell immunity that involves secretion of the high-mobility-group box 1 (HMGB1) alarmin protein by dying tumor cells and the action of HMGB1 on Toll-like receptor 4 (TLR4) expressed by dendritic cells (DCs). During chemotherapy or radiotherapy, DCs require signaling through TLR4 and its adaptor MyD88 for efficient processing and cross-presentation of antigen from dying tumor cells. Patients with breast cancer who carry a TLR4 loss-of-function allele relapse more quickly after radiotherapy and chemotherapy than those carrying the normal TLR4 allele. These results delineate a clinically relevant immunoadjuvant pathway triggered by tumor cell death.

  3. Monte Carlo simulation of the photoneutron field in linac radiotherapy treatments with different collimation systems

    NASA Astrophysics Data System (ADS)

    Zanini, A.; Durisi, E.; Fasolo, F.; Ongaro, C.; Visca, L.; Nastasi, U.; Burn, K. W.; Scielzo, G.; Adler, J. O.; Annand, J. R. M.; Rosner, G.

    2004-02-01

    Bremsstrahlung photon beams produced by linac accelerators are currently the most commonly used method of radiotherapy for tumour treatments. When the photon energy exceeds 10 MeV the patient receives an undesired dose due to photoneutron production in the accelerator head. In the last few decades, new sophisticated techniques such as multileaf collimators have been used for a better definition of the target volume. In this case it is crucial to evaluate the photoneutron dose produced after giant dipole resonance (GDR) excitation of the high Z materials (mainly tungsten and lead) constituting the collimator leaves in view of the optimization of the radiotherapy treatment. A Monte Carlo approach has been used to calculate the photoneutron dose arising from the GDR reaction during radiotherapy with energetic photon beams. The simulation has been performed using the code MCNP4B-GN which is based on MCNP4B, but includes a new routine GAMMAN to model photoneutron production. Results for the facility at IRCC (Istituto per la Ricerca e la Cura del Cancro) Candiolo (Turin), which is based on 18 MV x-rays from a Varian Clinac 2300 C/D, are presented for a variety of different collimator configurations.

  4. Monte Carlo simulation of the photoneutron field in linac radiotherapy treatments with different collimation systems.

    PubMed

    Zanini, A; Durisi, E; Fasolo, F; Ongaro, C; Visca, L; Nastasi, U; Burn, K W; Scielzo, G; Adler, J O; Annand, J R M; Rosner, G

    2004-02-21

    Bremsstrahlung photon beams produced by linac accelerators are currently the most commonly used method of radiotherapy for tumour treatments. When the photon energy exceeds 10 MeV the patient receives an undesired dose due to photoneutron production in the accelerator head. In the last few decades, new sophisticated techniques such as multileaf collimators have been used for a better definition of the target volume. In this case it is crucial to evaluate the photoneutron dose produced after giant dipole resonance (GDR) excitation of the high Z materials (mainly tungsten and lead) constituting the collimator leaves in view of the optimization of the radiotherapy treatment. A Monte Carlo approach has been used to calculate the photoneutron dose arising from the GDR reaction during radiotherapy with energetic photon beams. The simulation has been performed using the code MCNP4B-GN which is based on MCNP4B, but includes a new routine GAMMAN to model photoneutron production. Results for the facility at IRCC (Istituto per la Ricerca e la Cura del Cancro) Candiolo (Turin), which is based on 18 MV x-rays from a Varian Clinac 2300 C/D, are presented for a variety of different collimator configurations.

  5. Characterization of spatial distortion in a 0.35 T MRI-guided radiotherapy system

    NASA Astrophysics Data System (ADS)

    Ginn, John S.; Agazaryan, Nzhde; Cao, Minsong; Baharom, Umar; Low, Daniel A.; Yang, Yingli; Gao, Yu; Hu, Peng; Lee, Percy; Lamb, James M.

    2017-06-01

    Spatial distortion results in image deformation that can degrade accurate targeting and dose calculations in MRI-guided adaptive radiotherapy. The authors present a comprehensive assessment of a 0.35 T MRI-guided radiotherapy system’s spatial distortion using two commercially-available phantoms with regularly spaced markers. Images of the spatial integrity phantoms were acquired using five clinical protocols on the MRI-guided radiotherapy machine with the radiotherapy gantry positioned at various angles. Software was developed to identify and localize all phantom markers using a template matching approach. Rotational and translational corrections were implemented to account for imperfect phantom alignment. Measurements were made to assess uncertainties arising from susceptibility artifacts, image noise, and phantom construction accuracy. For a clinical 3D imaging protocol with a 1.5 mm reconstructed slice thickness, 100% of spheres within a 50 mm radius of isocenter had a 3D deviation of 1 mm or less. Of the spheres within 100 mm of isocenter, 99.9% had a 3D deviation less than 1 mm. 94.8% and 100% of the spheres within 175 mm were found to be within 1 mm and 2 mm of the expected positions in 3D respectively. Maximum 3D distortions within 50 mm, 100 mm and 175 mm of isocenter were 0.76 mm, 1.15 mm and 1.88 mm respectively. Distortions present in images acquired using the real-time imaging sequence were less than 1 mm for 98.1% and 95.0% of the cylinders within 50 mm and 100 mm of isocenter. The corresponding maximum distortion in these regions was 1.10 mm and 1.67 mm. These results may be used to inform appropriate planning target volume (PTV) margins for 0.35 T MRI-guided radiotherapy. Observed levels of spatial distortion should be explicitly considered when using PTV margins of 3 mm or less or in the case of targets displaced from isocenter by more than 50 mm.

  6. Chemoradiation therapy using radiotherapy, systemic chemotherapy with 5-fluorouracil and nedaplatin, and intra-arterial infusion using carboplatin for locally advanced head and neck cancer - Phase II study.

    PubMed

    Fuwa, Nobukazu; Kodaira, Takesi; Furutani, Kazuhisa; Tachibana, Hiroyuki; Nakamura, Tatsuya; Daimon, Takasi

    2007-11-01

    To improve the treatment results for locally advanced head and neck cancer, chemoradiation therapy by radiotherapy, systemic chemotherapy with 5-fluorouracil (5FU) and nedaplatin (NDP), and intra-arterial therapy using carboplatin (CBDCA) was performed. Thirty-two patients were entered into the study between July 1997 and August 2002. According to the TNM staging (1997), 14 patients had stage III lesions, and 19 patients had stage IV (M0) lesions. Alternating chemoradiotherapy was performed by the following regimen. Initially, systemic chemotherapy was administered, followed by 4 weeks of radiotherapy (36Gy/20 fractions; wide field irradiation) starting 2 days after chemotherapy, a second course of systemic chemotherapy 2 days after radiotherapy, and a second course of a reduced field radiotherapy (30Gy/15 fractions) 2 days after chemotherapy. Arterial injection therapy was administered in the latter half of radiotherapy after the end of the second course of systemic chemotherapy. For systemic chemotherapy, 5FU at 3500mg/m(2)/120h was intravenously administered for 5 days (Days 1-5), and NDP at 120mg/m(2)/6h was administered on Day 6. An intra-arterial agent using CBDCA was continuously infused by a portable electrical pump for 4 (to 6) weeks. The total dose of CBDCA was AUC 6 as established by Calvert's formula. The 5-year local control rate was 59%. The 5-year overall survival rate was 51%. There were no clinically significant adverse effects. Chemoradiation therapy by radiotherapy, systemic chemotherapy, and intra-arterial chemotherapy for locally advanced head and neck cancer may be useful for improving treatment results.

  7. Design and implementation of an electronic data recording and processing system for physics quality control checks in external beam radiotherapy.

    PubMed

    Patel, I; Kirby, M C

    2007-02-01

    Quality control (QC) of external beam radiotherapy equipment ensures that commissioning performance is maintained. Paper based data recording is still used for QC, but this is resource intensive in terms of data calculation and processing. Electronic systems of data recording have many advantages; for example, they facilitate the analysis of data on a regular basis, allowing the user to examine the "health" of each machine; they help review and audit local frequencies of each check and can possibly predict component failure. They also allow for secure calculation of results and automatic charting for routine trend analysis. Initially, data recording at our centre was paper-based for daily, weekly and monthly checks. This paper system has been successfully replaced with an electronic system for QC data recording and processing for linear accelerators and superficial units. The system makes use of personal digital assistants and networked laptops for online recording of data, and networked desktop PCs for offline work. The systems of data recording have been designed using the power of macros within Microsoft Excel, which automatically calculate each QC parameter and charts the data recorded for long-term analysis of trends. As of the beginning of 2006, these systems have been fully implemented. The benefits of implementing such a system are numerous, for example, central storage, backup and archiving of data, for greater security and reducing operator errors in calculations. Other benefits are discussed within the paper. In the future, we hope to develop similar systems of data recording for QC checks on other radiotherapy equipment.

  8. Fatigue in advanced cancer patients attending an outpatient palliative radiotherapy clinic as screened by the Edmonton Symptom Assessment System.

    PubMed

    Zeng, Liang; Koo, Kaitlin; Zhang, Liying; Jon, Florencia; Dennis, Kristopher; Holden, Lori; Nguyen, Janet; Tsao, May; Barnes, Elizabeth; Danjoux, Cyril; Sahgal, Arjun; Chow, Edward

    2012-05-01

    Advanced cancer patients present with a variety of physical and psychological symptoms. Fatigue is one such symptom which reduces overall quality of life and is difficult to manage. The purpose of this study was to report the presence, severity, and correlating factors of fatigue in advanced cancer patients attending an outpatient palliative radiotherapy clinic. Patients referred to the Rapid Response Radiotherapy Program between January 1999 and October 2009 completed the Edmonton Symptom Assessment System (ESAS) prior to consultation. Demographic information including age, Karnofsky Performance Status (KPS), gender, and primary cancer sites were collected. Ordinal logistic regression analysis was conducted to determine relationships between demographic information, other ESAS items, and levels of fatigue. Multivariate ordinal logistic regression analysis was used to determine the most significant predictors of fatigue. A p value of <0.05 was considered statistically significant. A total of 1,397 patients completed the ESAS prior to consultation. Median age was 68 years (range, 21-95), median KPS was 60 (range, 10-100), and slightly more males completed the ESAS (53.0%). Common primary cancers were of the lung (35.8%), breast (20.7%), and prostate (17.7%). Only 179 (12.8%) patients reported no fatigue; the majority of patients reported moderate (31.8%) or severe (34.4%) fatigue. A low KPS (p < 0.0001), being female (p = 0.0056), or being referred for bone metastases (p = 0.0185) significantly correlated with higher levels of fatigue. Patients with a genitourinary primary cancer (p = 0.0078) and/or referred for malignant spinal cord compression (p = 0.0004) reported less fatigue. All other ESAS items were significantly related to fatigue. The most significant predictors of fatigue were pain (p < 0.0001, odds ratio (OR) = 1.07), nausea (p = 0.0010, OR = 1.10), depression (p < 0.0001, OR = 1.10), drowsiness (p < 0.0001, OR = 1.33), dyspnea (p = 0.0003, OR = 1

  9. A simple DVH generation technique for various radiotherapy treatment planning systems for an independent information system

    NASA Astrophysics Data System (ADS)

    Min, Byung Jun; Nam, Heerim; Jeong, Il Sun; Lee, Hyebin

    2015-07-01

    In recent years, the use of a picture archiving and communication system (PACS) for radiation therapy has become the norm in hospital environments and has been suggested for collecting and managing data using Digital Imaging and Communication in Medicine (DICOM) objects from different treatment planning systems (TPSs). However, some TPSs do not provide the ability to export the dose-volume histogram (DVH) in text or other format. In addition, plan review systems for various TPSs often allow DVH recalculations with different algorithms. These algorithms result in inevitable discrepancies between the values obtained with the recalculation and those obtained with TPS itself. The purpose of this study was to develop a simple method for generating reproducible DVH values by using the TPSs. Treatment planning information, including structures and delivered dose, was exported in the DICOM format from the Eclipse v8.9 or the Pinnacle v9.6 planning systems. The supersampling and trilinear interpolation methods were employed to calculate the DVH data from 35 treatment plans. The discrepancies between the DVHs extracted from each TPS and those extracted by using the proposed calculation method were evaluated with respect to the supersampling ratio. The volume, minimum dose, maximum dose, and mean dose were compared. The variations in DVHs from multiple TPSs were compared by using the MIM software v6.1, which is a commercially available treatment planning comparison tool. The overall comparisons of the volume, minimum dose, maximum dose, and mean dose showed that the proposed method generated relatively smaller discrepancies compared with TPS than the MIM software did compare with the TPS. As the structure volume decreased, the overall percent difference increased. The largest difference was observed in small organs such as the eye ball, eye lens, and optic nerve which had volume below 10 cc. A simple and useful technique was developed to generate a DVH with an acceptable

  10. Role of Systemic Therapy in the Development of Lung Sequelae After Conformal Radiotherapy in Breast Cancer Patients

    SciTech Connect

    Varga, Zoltan; Cserhati, Adrienn; Kelemen, Gyoengyi; Boda, Krisztina; Thurzo, Laszlo; Kahan, Zsuzsanna

    2011-07-15

    Purpose: To analyze the risk of radiogenic lung damage in breast cancer patients after conformal radiotherapy and different forms of systemic treatment. Methods and Materials: In 328 patients receiving sequential taxane-based chemotherapy, concomitant hormone therapy (tamoxifen or aromatase inhibitors), or no adjuvant systemic therapy, symptomatic and asymptomatic lung sequelae were prospectively evaluated via the detection of visible CT abnormalities, 3 months or 1 year after the completion of the radiotherapy. Results: Significant positive associations were detected between the development of both pneumonitis and fibrosis of Grade 1 and patient age, ipsilateral mean lung dose, volume of the ipsilateral lung receiving 20 Gy, and irradiation of the regional lymph nodes. In multivariate analysis, age and mean lung dose proved to be independent predictors of early (odds ratio [OR] = 1.035, 95% confidence interval [CI] 1.011-1.061 and OR = 1.113, 95% CI 1.049-1.181, respectively) and late (OR = 1.074, 95% CI 1.042-1.107 and OR = 1.207, 95% CI 1.124-1.295, respectively) radiogenic lung damage, whereas the role of systemic therapy was significant in the development of Grade 1 lung fibrosis (p = 0.01). Among the various forms of systemic therapy, tamoxifen increased the risk of late lung sequelae (OR = 2.442, 95% CI 1.120-5.326, p = 0.025). No interaction was demonstrated between the administration of systemic therapy and the other above-mentioned parameters as regards the risk of radiogenic lung damage. Conclusions: Our analyses demonstrate the independent role of concomitant tamoxifen therapy in the development of radiogenic lung fibrosis but do not suggest such an effect for the other modes of systemic treatment.

  11. Validation of in-house treatment planning system software for cobalt-60 teletherapy unit at two radiotherapy installations

    NASA Astrophysics Data System (ADS)

    Mu'minah, I. A. S.; Toresano, L. O. H. Z.; Wibowo, W. E.; Sugiyantari; Pawiro, S. A.

    2016-03-01

    DSSuperDose v.1.0 is an in-house treatment planning system (TPS) developed by Medical Physics and Biophysics Laboratory (LFMB) Universitas Indonesia as a treatment planning software for Cobalt-60 teletherapy unit. The main objective of this study was the validation of in-house TPS calculation as an essential part in quality assurance (QA) of radiotherapy. Validation of an in-house TPS was performed with two Cobalt-60 teletherapy units by comparison between in-house TPS and ISIS TPS and by measurements of absorbed dose. Mean dose deviations between in-house TPS and measurement were (1.97 ± 2.42)% for open field, (1.32 ± 1.30)% for tray field, and (2.91 ± 2.36)% for wedge field treatments. In-house TPS provide optimal planning for open and tray beam conditions with depth fewer than 10 cm (≤ 10 cm) and field sizes up to 20×20 cm2, while for wedge beam conditions with field sizes fewer than the physical size of the wedge. Comparison of in-house TPS and ISIS TPS demonstrated a good match of 96%. From the results, it is concluded that DSSuperDose v.1.0 is adequately accurate for treatment planning of radiotherapy.

  12. Evaluation of dose calculations accuracy of a commercial treatment planning system for the head and neck region in radiotherapy.

    PubMed

    Bahreyni Toossi, Mohammad Taghi; Farhood, Bagher; Soleymanifard, Shokouhozaman

    2017-01-01

    The objective was to quantify dose calculation accuracy of TiGRT TPS for head and neck region in radiotherapy. In radiotherapy of head and neck cancers, treatment planning is difficult, due to the complex shape of target volumes and also to spare critical and normal structures. These organs are often very near to the target volumes and have low tolerance to radiation. In this regard, dose calculation accuracy of treatment planning system (TPS) must be high enough. Thermoluminescent dosimeter-100 (TLD-100) chips were used within RANDO phantom for dose measurement. TiGRT TPS was also applied for dose calculation. Finally, difference between measured doses (Dmeas) and calculated doses (Dcalc) was obtained to quantify the dose calculation accuracy of the TPS at head and neck region. For in-field regions, in some points, the TiGRT TPS overestimated the dose compared to the measurements and for other points underestimated the dose. For outside field regions, the TiGRT TPS underestimated the dose compared to the measurements. For most points, the difference values between Dcalc and Dmeas for the in-field and outside field regions were less than 5% and 40%, respectively. Due to the sensitive structures to radiation in the head and neck region, the dose calculation accuracy of TPSs should be sufficient. According to the results of this study, it is concluded that the accuracy of dose calculation of TiGRT TPS is enough for in-field and out of field regions.

  13. Accuracy of EGSnrc, Geant4 and PENELOPE Monte Carlo systems for simulation of electron scatter in external beam radiotherapy

    PubMed Central

    Faddegon, Bruce A; Kawrakow, Iwan; Kubyshin, Yuri; Perl, Joseph; Sempau, Josep; Urban, Laszlo

    2012-01-01

    Three widely used Monte Carlo systems were benchmarked against recently published measurements of the angular distribution of 13 MeV and 20 MeV electrons scattered from foils of different atomic number and thickness. Source and geometry was simulated in detail to calculate electron fluence profiles 118.2 cm from the exit window. Results were compared to the measured fluence profiles and the characteristic angle where the fluence drops to 1/e of its maximum value. EGSnrc and PENELOPE results, on average, agreed with measurement within 1 standard deviation experimental uncertainty, with EGSnrc estimating slightly lower scatter than measurement, PENELOPE slightly higher scatter. Geant4.9.2 overestimated the characteristic angle for the lower atomic number foils by as much as 10%. Retuning of the scatter distributions in Geant4 led to a much better agreement with measurement, close to that achieved with the other codes. The 3% differences from measurement seen with all codes for at least some of the foils would result in clinically significant errors in the fluence profiles (2%/4 mm), given accurate knowledge of the electron source and treatment head geometry used in radiotherapy. Further improvement in simulation accuracy is needed to achieve 1%/1 mm agreement with measurement for the full range of beam energies, foil atomic number and thickness used in radiotherapy. EGSnrc would achieve this accuracy with an increase in thickness of the mylar sheets in the monitor chamber, Penelope with a decrease in thickness. PMID:19779217

  14. Favorable Outcomes of Pediatric Patients Treated With Radiotherapy to the Central Nervous System Who Develop Radiation-Induced Meningiomas

    SciTech Connect

    Galloway, Thomas J.; Indelicato, Daniel J.; Amdur, Robert J.; Swanson, Erika L.; Morris, Christopher G.; Marcus, Robert B.

    2011-01-01

    Purpose: To report the outcome of patients treated at the University of Florida who developed meningiomas after radiation to the central nervous system (CNS) for childhood cancer. Methods and Materials: We retrospectively identified 10 patients aged {<=}19 years who received radiotherapy to sites in the craniospinal axis and subsequently developed a meningioma. We report the histology of the radiation-induced meningioma, treatment received, and ultimate outcome among this cohort of patients. Results: Meningioma was diagnosed at a median of 23.5 years after completion of the primary radiation. Fifty percent of second meningiomas were World Health Organization Grade 2 (atypical) or higher. All cases were managed with a single modality: resection alone (n = 7), fractionated radiotherapy (n = 2), and stereotactic radiosurgery (n = 1). The actuarial event-free survival and overall survival rate at 5 years after treatment for a radiation-induced meningioma was 89%. Three patients who underwent resection for retreatment experienced a Grade 3 toxicity. Conclusions: Radiation-induced meningiomas after treatment of pediatric CNS tumors are effectively managed with single-modality therapy. Such late-effect data inform the overall therapeutic ratio and support the continued role of selective irradiation in managing pediatric CNS malignancies.

  15. SU-E-J-134: An Augmented-Reality Optical Imaging System for Accurate Breast Positioning During Radiotherapy

    SciTech Connect

    Nazareth, D; Malhotra, H; French, S; Hoffmann, K; Merrow, C

    2014-06-01

    Purpose: Breast radiotherapy, particularly electronic compensation, may involve large dose gradients and difficult patient positioning problems. We have developed a simple self-calibrating augmented-reality system, which assists in accurately and reproducibly positioning the patient, by displaying her live image from a single camera superimposed on the correct perspective projection of her 3D CT data. Our method requires only a standard digital camera capable of live-view mode, installed in the treatment suite at an approximately-known orientation and position (rotation R; translation T). Methods: A 10-sphere calibration jig was constructed and CT imaged to provide a 3D model. The (R,T) relating the camera to the CT coordinate system were determined by acquiring a photograph of the jig and optimizing an objective function, which compares the true image points to points calculated with a given candidate R and T geometry. Using this geometric information, 3D CT patient data, viewed from the camera's perspective, is plotted using a Matlab routine. This image data is superimposed onto the real-time patient image, acquired by the camera, and displayed using standard live-view software. This enables the therapists to view both the patient's current and desired positions, and guide the patient into assuming the correct position. The method was evaluated using an in-house developed bolus-like breast phantom, mounted on a supporting platform, which could be tilted at various angles to simulate treatment-like geometries. Results: Our system allowed breast phantom alignment, with an accuracy of about 0.5 cm and 1 ± 0.5 degree. Better resolution could be possible using a camera with higher-zoom capabilities. Conclusion: We have developed an augmented-reality system, which combines a perspective projection of a CT image with a patient's real-time optical image. This system has the potential to improve patient setup accuracy during breast radiotherapy, and could possibly be

  16. Carcinoma of the extrahepatic biliary system--results of primary and adjuvant radiotherapy

    SciTech Connect

    Fields, J.N.; Emami, B.

    1987-03-01

    From 1975-1983, 20 patients with primary carcinomas of the gallbladder (GB) or extrahepatic bile ducts (EHBD) were irradiated with curative intent at the Washington University Medical Center and affiliated hospitals. Of the 17 patients with EHBD cancer, one received adjuvant irradiation after gross resection with positive microscopic margins. All others received primary irradiation for unresectable tumors, or for gross residual tumor after incomplete resection. The 8 patients receiving Ir192 implant in addition to external radiation showed improved survival compared to the 9 receiving external only: median 15 months (range 1.5-34 + months) versus 7 months (range 2.5-21 months). Failures were predominantly local-regional, with only one patient showing metastatic spread without known local-regional tumor. Adjuvant radiation therapy was given after cholecystectomy to 3 patients with GB cancers showing tumor extension beyond the serosa or to regional lymphatics. Of these, two survived at 22+ and 27+ months; the third died of local recurrence at 5 1/2 months. Although numbers are small, these results appear to support the use of adjuvant radiotherapy in patients with microscopic residual GB cancer. Aggressive local and regional radiotherapy can add to the quality and length of survival in both patient groups, that is, those with resectable lesions with high likelihood of microscopic residual, and also those with unresectable or gross residual disease after surgery.

  17. Carcinoma of the extrahepatic biliary system--results of primary and adjuvant radiotherapy.

    PubMed

    Fields, J N; Emami, B

    1987-03-01

    From 1975-1983, 20 patients with primary carcinomas of the gallbladder (GB) or extrahepatic bile ducts (EHBD) were irradiated with curative intent at the Washington University Medical Center and affiliated hospitals. Of the 17 patients with EHBD cancer, one received adjuvant irradiation after gross resection with positive microscopic margins. All others received primary irradiation for unresectable tumors, or for gross residual tumor after incomplete resection. The 8 patients receiving Ir192 implant in addition to external radiation showed improved (p = 0.06) survival compared to the 9 receiving external only: median 15 months (range 1.5-34 + months) versus 7 months (range 2.5-21 months). Failures were predominantly local-regional, with only one patient showing metastatic spread without known local-regional tumor. Adjuvant radiation therapy was given after cholecystectomy to 3 patients with GB cancers showing tumor extension beyond the serosa or to regional lymphatics. Of these, two survived at 22+ and 27+ months; the third died of local recurrence at 5 1/2 months. Although numbers are small, these results appear to support the use of adjuvant radiotherapy in patients with microscopic residual GB cancer. Aggressive local and regional radiotherapy can add to the quality and length of survival in both patient groups, that is, those with resectable lesions with high likelihood of microscopic residual, and also those with unresectable or gross residual disease after surgery.

  18. Evaluation of a Gafchromic EBT2 film dosimetry system for radiotherapy quality assurance.

    PubMed

    Aland, T; Kairn, T; Kenny, J

    2011-06-01

    This study examines the dosimetric accuracy of Gafchromic EBT2 model radiochromic film for use in radiotherapy quality assurance. In this study, film was scanned using an Epson Perfection V700 flatbed scanner in transmission mode at 75 DPI with the subsequent analysis performed using the red and blue colour channels and ImageJ software. Results of this study suggest that the conversion of film optical density to measured dose should, at present, utilise red channel data only, without application of a blue channel correction to the data. For the batch of film examined here, film uniformity and reproducibility appear to have improved compared with published results using older batches. The orientation of the film on the scanner and the side of the film facing the light source were found to have substantial effects on results. Based on the results of this study, it is possible to recommend the use of EBT2 film in routine quality assurance testing for radiotherapy, in situations where a dose uncertainty of up to 2.8% is acceptable.

  19. Evaluation of Imaging Dose From Different Image Guided Systems During Head and Neck Radiotherapy: A Phantom Study.

    PubMed

    Cheng, Chun Shing; Jong, Wei Loong; Ung, Ngie Min; Wong, Jeannie Hsiu Ding

    2016-12-09

    This work evaluated and compared the absorbed doses to selected organs in the head and neck region from the three image guided radiotherapy systems: cone-beam computed tomography (CBCT) and kilovoltage (kV) planar imaging using the On-board Imager(®) (OBI) as well as the ExacTrac(®) X-ray system, all available on the Varian Novalis TX linear accelerator. The head and neck region of an anthropomorphic phantom was used to simulate patients' head within the imaging field. Nanodots optically stimulated luminescent dosemeters were positioned at selected sites to measure the absorbed doses. CBCT was found to be delivering the highest dose to internal organs while OBI-2D gave the highest doses to the eye lenses. The setting of half-rotation in CBCT effectively reduces the dose to the eye lenses. Daily high-quality CBCT verification was found to increase the secondary cancer risk by 0.79%.

  20. Inhalation anesthesia in experimental radiotherapy: a reliable and time-saving system for multifractionation studies in a clinical department

    SciTech Connect

    Ang, K.K.; Van Der Kogel, A.J.; Van Der Schueren, E.

    1982-01-01

    An inhalation anesthesia system has been employed to overcome several of the limitations associated with the use of sodium pentobarbital and other i.p. administered anesthetics in experimental radiotherapy. The described method is reliable and time-saving. The depth and duration of anesthesia are easily controllable. Only 4 deaths have occurred with more than 6000 animal exposures. The use of polystyrene jigs is shown to provide adequate thermal isolation. Oxygen as a carrier of the anesthetic agent is expected to prevent a reduced tissue oxygenation and its radiobiological consequences. The whole system is constructed as a mobile unit in which up to 16 mice or rats can be anesthetized simultaneously and irradiated in a single field with clinical treatment equipment during short time intervals between patient irradiations. The described advantages of this method make it specially suited for experiments with protracted fractionation schedules.

  1. MO-G-BRE-01: A Real-Time Virtual Delivery System for Photon Radiotherapy Delivery Monitoring

    SciTech Connect

    Shi, F; Gu, X; Jiang, S; Jia, X; Graves, Y

    2014-06-15

    Purpose: Treatment delivery monitoring is important for radiotherapy, which enables catching dosimetric error at the earliest possible opportunity. This project develops a virtual delivery system to monitor the dose delivery process of photon radiotherapy in real-time using GPU-based Monte Carlo (MC) method. Methods: The simulation process consists of 3 parallel CPU threads. A thread T1 is responsible for communication with a linac, which acquires a set of linac status parameters, e.g. gantry angles, MLC configurations, and beam MUs every 20 ms. Since linac vendors currently do not offer interface to acquire data in real time, we mimic this process by fetching information from a linac dynalog file at the set frequency. Instantaneous beam fluence map (FM) is calculated. A FM buffer is also created in T1 and the instantaneous FM is accumulated to it. This process continues, until a ready signal is received from thread T2 on which an inhouse developed MC dose engine executes on GPU. At that moment, the accumulated FM is transferred to T2 for dose calculations, and the FM buffer in T1 is cleared. Once the calculation finishes, the resulting 3D dose distribution is directed to thread T3, which displays it in three orthogonal planes overlaid on the CT image for treatment monitoring. This process continues to monitor the 3D dose distribution in real-time. Results: An IMRT and a VMAT cases used in our patient-specific QA are studied. Maximum dose differences between our system and treatment planning system are 0.98% and 1.58% for the two cases, respectively. The average time per MC calculation is 0.1sec with <2% relative uncertainty. The update frequency of ∼10Hz is considered as real time. Conclusion: By embedding a GPU-based MC code in a novel data/work flow, it is possible to achieve real-time MC dose calculations to monitor delivery process.

  2. Optimization and quality assurance of an image-guided radiation therapy system for intensity-modulated radiation therapy radiotherapy.

    PubMed

    Tsai, Jen-San; Micaily, Bizhan; Miyamoto, Curtis

    2012-01-01

    To develop a quality assurance (QA) of XVI cone beam system (XVIcbs) for its optimal imaging-guided radiotherapy (IGRT) implementation, and to construe prostate tumor margin required for intensity-modulated radiation therapy (IMRT) if IGRT is unavailable. XVIcbs spatial accuracy was explored with a humanoid phantom; isodose conformity to lesion target with a rice phantom housing a soap as target; image resolution with a diagnostic phantom; and exposure validation with a Radcal ion chamber. To optimize XVIcbs, rotation flexmap on coincidency between gantry rotational axis and that of XVI cone beam scan was investigated. Theoretic correlation to image quality of XVIcbs rotational axis stability was elaborately studied. Comprehensive QA of IGRT using XVIcbs has initially been explored and then implemented on our general IMRT treatments, and on special IMRT radiotherapies such as head and neck (H and N), stereotactic radiation therapy (SRT), stereotactic radiosurgery (SRS), and stereotactic body radiotherapy (SBRT). Fifteen examples of prostate setup accounted for 350 IGRT cone beam system were analyzed. IGRT accuracy results were in agreement ± 1 mm. Flexmap 0.25 mm met the manufacturer's specification. Films confirmed isodose coincidence with target (soap) via XVIcbs, otherwise not. Superficial doses were measured from 7.2-2.5 cGy for anatomic diameters 15-33 cm, respectively. Image quality was susceptible to rotational stability or patient movement. IGRT using XVIcbs on general IMRT treatments such as prostate, SRT, SRS, and SBRT for setup accuracy were verified; and subsequently coordinate shifts corrections were recorded. The 350 prostate IGRT coordinate shifts modeled to Gaussian distributions show central peaks deviated off the isocenter by 0.6 ± 3.0 mm, 0.5 ± 4.5 mm in the X(RL)- and Z(SI)-coordinates, respectively; and 2.0 ± 3.0 mm in the Y(AP)-coordinate as a result of belly and bladder capacity variations. Sixty-eight percent of confidence was within

  3. Optimization and quality assurance of an image-guided radiation therapy system for intensity-modulated radiation therapy radiotherapy

    SciTech Connect

    Tsai, Jen-San; Micaily, Bizhan; Miyamoto, Curtis

    2012-10-01

    To develop a quality assurance (QA) of XVI cone beam system (XVIcbs) for its optimal imaging-guided radiotherapy (IGRT) implementation, and to construe prostate tumor margin required for intensity-modulated radiation therapy (IMRT) if IGRT is unavailable. XVIcbs spatial accuracy was explored with a humanoid phantom; isodose conformity to lesion target with a rice phantom housing a soap as target; image resolution with a diagnostic phantom; and exposure validation with a Radcal ion chamber. To optimize XVIcbs, rotation flexmap on coincidency between gantry rotational axis and that of XVI cone beam scan was investigated. Theoretic correlation to image quality of XVIcbs rotational axis stability was elaborately studied. Comprehensive QA of IGRT using XVIcbs has initially been explored and then implemented on our general IMRT treatments, and on special IMRT radiotherapies such as head and neck (H and N), stereotactic radiation therapy (SRT), stereotactic radiosurgery (SRS), and stereotactic body radiotherapy (SBRT). Fifteen examples of prostate setup accounted for 350 IGRT cone beam system were analyzed. IGRT accuracy results were in agreement {+-} 1 mm. Flexmap 0.25 mm met the manufacturer's specification. Films confirmed isodose coincidence with target (soap) via XVIcbs, otherwise not. Superficial doses were measured from 7.2-2.5 cGy for anatomic diameters 15-33 cm, respectively. Image quality was susceptible to rotational stability or patient movement. IGRT using XVIcbs on general IMRT treatments such as prostate, SRT, SRS, and SBRT for setup accuracy were verified; and subsequently coordinate shifts corrections were recorded. The 350 prostate IGRT coordinate shifts modeled to Gaussian distributions show central peaks deviated off the isocenter by 0.6 {+-} 3.0 mm, 0.5 {+-} 4.5 mm in the X(RL)- and Z(SI)-coordinates, respectively; and 2.0 {+-} 3.0 mm in the Y(AP)-coordinate as a result of belly and bladder capacity variations. Sixty-eight percent of confidence was

  4. Successful Treatment of Advanced Primary Cutaneous Apocrine Carcinoma on the Scrotum with Systemic Chemotherapy and Radiotherapy Followed by Denosumab

    PubMed Central

    Furudate, Sadanori; Fujimura, Taku; Tsukada, Akira; Sato, Yota; Hidaka, Takanori; Tanita, Kayo; Kambayashi, Yumi; Haga, Takahiro; Hashimoto, Akira; Aiba, Setsuya

    2017-01-01

    Primary cutaneous apocrine carcinoma (PCAC) is a rare and highly aggressive cutaneous adnexal type of tumor that has a high metastasis rate and a poor prognosis. Although there are several case reports describing the successful treatment of PCAC with chemoradiotherapy or molecular targeting therapy, no standard therapy for the treatment of advanced PCAC has been established yet. Since receptor activator of nuclear factor kappa-B ligand (RANKL) is expressed in cancers of apocrine origin, leading to immunosuppression at the tumor site, we hypothesized that targeting RANKL with denosumab might be useful for the treatment of PCAC. In this report, we describe a case with advanced PCAC on the scrotum successfully treated with systemic chemotherapy using carboplatin and paclitaxel, and radiotherapy followed by denosumab. PMID:28203164

  5. SU-E-T-411: Dosimetric Comparison Between Two Multileaf Collimator Systems for Stereotactic Radiosurgery and Radiotherapy.

    PubMed

    Asnaashari, K; Chow, J; Heydarian, M

    2012-06-01

    This aim of this study is to compare the dosimetric parameters of two multileaf collimator (MLC) systems: (1) the beam modulator (BM), which is the MLC commercial name for Elekta 'Synergy S' linear accelerator; and (2) Radionics micro-MLC (MMLC). Dosimetric parameters of percentage depth dose (PDD), in-plane and cross-plane beam profile, penumbra, MLC leakage and transmission for a 6 MV photon beam with different field sizes and depths were measured using ionization chamber, film, solid water phantom and water tank. At the same time, the BM and MMLC were modeled using the BEAMnrc code and the above dosimetric parameters were calculated using Monte Carlo simulations. Energy fluence spectra for the two MLC were determined using the BEAMnrc and BEAMDP. We found that dosimetric parameters (PDD, beam profile, energy fluence spectra, leakage and transmission) of the two MLC were similar, except for penumbra. The leaf-side and leaf-end 20%-80% penumbras at 10 cm depth for a 10×10 cm(2) field were 4.8 and 5.1 mm for the MMLC and 5.3 mm and 6.3 mm for the BM, respectively. The maximum percentage of the leakage for the BM and MMLC are 1.3% and 1.2%, while the average percentage of leakage for the BM and MMLC are 0.9% and 1%. Based on their dosimetric characteristics for stereotactic radiosurgery and radiotherapy, it can be concluded that both the BM and MMLC can be used effectively, though the latter showed slightly sharper dose penumbra especially in the leaf-end direction. However, the BM has the advantages of producing considerably larger field at isocenter and having a greater isocenter clearance compared to the MMLC. The dosimetric data in this study should help radiotherapy staff to appreciate dependence of dosimetry on the MLC design and configuration for stereotactic radiosurgery and radiotherapy. Actual or potential conflicts of interest do not exist. © 2012 American Association of Physicists in Medicine.

  6. [Task sharing with radiotherapy technicians in image-guided radiotherapy].

    PubMed

    Diaz, O; Lorchel, F; Revault, C; Mornex, F

    2013-10-01

    The development of accelerators with on-board imaging systems now allows better target volumes reset at the time of irradiation (image-guided radiotherapy [IGRT]). However, these technological advances in the control of repositioning led to a multiplication of tasks for each actor in radiotherapy and increase the time available for the treatment, whether for radiotherapy technicians or radiation oncologists. As there is currently no explicit regulatory framework governing the use of IGRT, some institutional experiments show that a transfer is possible between radiation oncologists and radiotherapy technicians for on-line verification of image positioning. Initial training for every technical and drafting procedures within institutions will improve audit quality by reducing interindividual variability.

  7. Use of implanted markers and interportal adjustment with real-time tracking radiotherapy system to reduce intrafraction prostate motion.

    PubMed

    Shimizu, Shinichi; Osaka, Yasuhiro; Shinohara, Nobuo; Sazawa, Ataru; Nishioka, Kentaro; Suzuki, Ryusuke; Onimaru, Rikiya; Shirato, Hiroki

    2011-11-15

    Interportal adjustment was applied to patients with prostate cancer using three fiducial markers and two sets of fluoroscopy in a real-time tumor-tracking radiotherapy (RTRT) system. The incidence of table position adjustment required to keep intrafractional uncertainty within 2.0 mm was investigated in this study. The coordinates of the center of gravity of the three fiducial markers were measured at the start of every portal irradiation in intensity-modulated radiotherapy (IMRT) with seven ports. The table position was adjusted to the planned position if the discrepancy was larger than 2.0 mm in the anterior-posterior (AP), cranial-caudal (CC), or left-right (LR) directions. In total, we analyzed 4,541 observations in 20 patients who received 70 Gy in 30 fractions (7.6 times a day on average). The incidence of table position adjustment at 10 minutes from the initial setup of each treatment was 14.2%, 12.3%, and 5.0% of the observations in the AP, CC, and LR directions, respectively. The accumulated incidence of the table position adjustment was significantly higher at 10 minutes than at 2 minutes for AP (p = 0.0033) and CC (p = 0.0110) but not LR (p = 0.4296). An adjustment greater than 5 mm was required at least once in the treatment period in 11 (55%) patients. Interportal adjustment of table position was required in more than 10% of portal irradiations during the 10-minute period after initial setup to maintain treatment accuracy within 2.0 mm. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Analysis of Dose at the Site of Second Tumor Formation After Radiotherapy to the Central Nervous System

    SciTech Connect

    Galloway, Thomas J.; Indelicato, Daniel J.; Amdur, Robert J.; Morris, Christopher G.; Swanson, Erika L.; Marcus, Robert B.

    2012-01-01

    Purpose: Second tumors are an uncommon complication of multimodality treatment of childhood cancer. The present analysis attempted to correlate the dose received as a component of primary treatment and the site of the eventual development of a second tumor. Methods and Materials: We retrospectively identified 16 patients who had received radiotherapy to sites in the craniospinal axis and subsequently developed a second tumor. We compared the historical fields and port films of the primary treatment with the modern imaging of the second tumor locations. We classified the location of the second tumors as follows: in the boost field; marginal to the boost field, but in a whole-brain field; in a whole-brain field; marginal to the whole brain/primary treatment field; and distant to the field. We divided the dose received into 3 broad categories: high dose (>45 Gy), moderate dose (20-36 Gy), and low dose (<20 Gy). Results: The most common location of the second tumor was in the whole brain field (57%) and in the moderate-dose range (81%). Conclusions: Our data contradict previous publications that suggested that most second tumors develop in tissues that receive a low radiation dose. Almost all the second tumors in our series occurred in tissue within a target volume in the cranium that had received a moderate dose (20-36 Gy). These findings suggest that a major decrease in the brain volume that receives a moderate radiation dose is the only way to substantially decrease the second tumor rate after central nervous system radiotherapy.

  9. Classification and Reporting of Late Radiographic Changes After Lung Stereotactic Body Radiotherapy: Proposing a New System.

    PubMed

    Raziee, Hamid; Hope, Andrew; Faruqi, Salman; Yap, Mei Ling; Roberts, Heidi; Kandel, Sonja; Le, Lisa W; Brade, Anthony; Cho, John; Sun, Alex; Bezjak, Andrea; Giuliani, Meredith E

    2015-11-01

    Radiation-induced parenchymal lung changes after stereotactic body radiotherapy are common, and can obscure the primary tumor site. In this study we propose a structured radiographic reporting tool for characterization of these changes, pilot its feasibility in a group of radiation oncologists, and test the interrater agreement. We could demonstrate the applicability of the scale, with a fair to moderate agreement. The purpose of the study was to design and pilot a synoptic scale for characterization of late radiographic changes after lung stereotactic body radiotherapy (SBRT). A participatory design process involving 6 radiation oncologists and 2 thoracic radiologists was used in the scale's design. Seventy-seven early-stage non-small-cell lung cancer patients who were treated with SBRT were included, and after treatment their serial computed tomography (CT) images were scored by 6 radiation oncologists. Gwet's First-order Agreement Coefficient (AC1) and a leave-one-out (LOO) analysis was used to assess interrater reliability and variability among raters, respectively. The scale reports on 5 independent categories including "tumor in primary site," "tumor in involved lobe," "consolidation," "volume loss," and "ground-glass or interstitial changes." At each time point, each category is reported as "increased," "stable," "decreased," "obscured," or "not present," compared with the previous. The total number of rated images for the pilot ranged from 450 at 6 months to 84 at 48 months. The primary tumor site was scored as obscured in 38% to 40% of ratings from 12 months onward; 3% to 5% of primary tumors were scored as "increased." Consolidation, volume loss, and ground-glass or interstitial changes were increasingly marked as "stable" with time. At 24 months, AC1 was 0.28 (LOO, 0.22-0.42), 0.47 (LOO, 0.39-0.72), 0.45 (LOO, 0.42-0.50), 0.21 (LOO, 0.15-0.26), and 0.25 (LOO, 0.20-0.38) for the 5 categories listed, respectively. In a population of clinicians, this scale

  10. Real-time monitoring system with accelerator controlling: An improvement of radiotherapy monitoring based on binocular location and classification.

    PubMed

    Chai, Lei; Chen, Da; Tang, Xiao-Bing; Ge, Yun; Chen, Ying; Li, Jun

    2017-02-21

    Real-time monitoring and amendment of patient position is important for the radiotherapy. However, using electronic portal imaging device (EPID) and cone beam computer tomography (CBCT) in the clinical practice generate different degrees of delay, so that they cannot achieve the purpose of real-time application. Meanwhile, a few products come with the function of the real-time monitoring and amendment, such as CyberKnife, which is too expensive for the common people. The objective of this study is to develop and test a novel independent system to monitor treatment center and amend the position of patient, which is applicable to most accelerators, based on binocular location. The system monitors the treatment center by tracking the markers attached to the patient. Once the treatment center shifts, the system uses the magic finger, which is developed to control the treatment bet automatically to adjust the treatment bed position. To improve the monitoring accuracy, we trained the data collected from the clinic based on SVM (Support Vector Machine). Thus, the training results assist users to adjust the feasible degree of the monitoring. The experiment results showed that using this new monitoring system, the monitoring resolution reached 0.5 mm, and the error ratio of the judgment was less than 1.5%.

  11. (68)Ga-PSMA Ligand PET/CT-based Radiotherapy for Lymph Node Relapse of Prostate Cancer After Primary Therapy Delays Initiation of Systemic Therapy.

    PubMed

    Henkenberens, Christoph; VON Klot, Christoph A; Ross, Tobias L; Bengel, Frank M; Wester, Hans-Jürgen; Katja, Hüper; Christiansen, Hans; Derlin, Thorsten

    2017-03-01

    To evaluate (68)Ga-PSMA ligand positron-emission tomography-computed tomography (PET/CT)-based radiotherapy for lymph node metastases of prostate cancer after primary therapy. Twenty-three patients received radiotherapy for PSMA ligand-positive lymph node metastases. The median follow-up time was 12.4 (range=6.0-28.5) months. The median pre-treatment prostate-specific antigen (PSA) decreased from 2.75 (range=0.52-8.92) ng/ml to a nadir of 1.37 (range=0.11-8.00) ng/ml (p=0.001) following radiotherapy. Except for one patient (4.4%), PSA level decreased in 22 patients (95.6%). The biochemical failure-free survival and time to initiation of systemic therapy at the median follow-up were 95.6% and 100%, respectively. Three patients (12.9%) presented with recurrent disease outside the initial radiation field. No grade III acute toxicities or late grade II toxicities were observed. (68)Ga-PSMA ligand PET/CT-based radiotherapy is a promising local treatment option for isolated lymph node metastases of prostate cancer. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  12. The Technique, Resources and Costs of Stereotactic Body Radiotherapy of Prostate Cancer: A Comparison of Dose Regimens and Delivery Systems.

    PubMed

    Sharieff, Waseem; Greenspoon, Jeffrey N; Dayes, Ian; Chow, Tom; Wright, James; Lukka, Himu

    2016-02-01

    Robotic system has been used for stereotactic body radiotherapy (SBRT) of prostate cancer. Arc-based and fixed-gantry systems are used for hypofractionated regimens (10-20 fractions) and the standard regimen (39 fractions); they may also be used to deliver SBRT. Studies are currently underway to compare efficacy and safety of these systems and regimens. Thus, we describe the technique and required resources for the provision of robotic SBRT in relation to the standard regimen and other systems to guide investment decisions. Using administrative data of resource volumes and unit prices, we computed the cost per patient, cost per cure and cost per quality adjusted life year (QALY) of four regimens (5, 12, 20 and 39 fractions) and three delivery systems (robotic, arc-based and fixed-gantry) from a payer's perspective. We performed sensitivity analyses to examine the effects of daily hours of operation and in-room treatment delivery times on cost per patient. In addition, we estimated the budget impact when a robotic system is preferred over an arc-based or fixed-gantry system. Costs of SBRT were $6333/patient (robotic), $4368/patient (arc-based) and $4443/patient (fixed-gantry). When daily hours of operation were varied, the cost of robotic SBRT varied from $9324/patient (2 hours daily) to $5250/patient (10 hours daily). This was comparable to the costs of 39 fraction standard regimen which were $5935/patient (arc-based) and $7992/ patient (fixed-gantry). In settings of moderate to high patient volume, robotic SBRT is cost effective compared to the standard regimen. If SBRT can be delivered with equivalent efficacy and safety, the arc-based system would be the most cost effective system.

  13. Positioning Accuracy in Stereotactic Radiotherapy Using a Mask System With Added Vacuum Mouth Piece and Stereoscopic X-Ray Positioning

    SciTech Connect

    Santvoort, Jan van Wiggenraad, Ruud; Bos, Petra

    2008-09-01

    Purpose: For cranial patients receiving stereotactic radiotherapy, we use the Exactrac stereoscopic X-ray system to optimize patient positioning. Patients are immobilized with the BrainLAB Mask System (BrainLAB, Feldkirchen, Germany). We have developed an adapter to this system that accommodates a vacuum mouth piece (VMP). Measurements with the Exactrac system have been performed to study the positioning accuracy after corrections with this system and to evaluate the accuracy of the VMP vs. the standard available upper jaw support (UJS). Methods and Materials: Positioning results were collected for 20 patients with the UJS and 20 patients with the VMP, before treatment (1,122 fractions) and after treatment (400 fractions). For all 6 degrees of freedom the average, the random error and systematic error were calculated. Results: The average vector length before and after correction with the Exactrac system was 2.1 {+-} 1.2 mm and 0.7 {+-} 0.6 mm respectively for UJS and 1.7 {+-} 0.7 mm and 0.4 {+-} 0.4 mm for VMP. Interfraction positioning for translations was greatly improved after correction with the Exactrac system (p < 0.0005) and is better with VMP than with UJS (p = 0.005). Outliers were greatly reduced. Interfraction rotations were significantly smaller for VMP. Intrafraction errors for vertical and longitudinal translations and for rotations were smaller for the VMP. Conclusions: Positioning correction using the Exactrac X-ray system greatly improves accuracy. Adding the VMP results in even better patient fixation and smaller rotations, making it a useful addition to the Mask System. Combined, this is a convenient and accurate alternative to invasive fixation methods.

  14. Multi-institutional clinical experience with the Calypso System in localization and continuous, real-time monitoring of the prostate gland during external radiotherapy

    SciTech Connect

    Kupelian, Patrick . E-mail: patrick.kupelian@orhs.org; Willoughby, Twyla; Mahadevan, Arul; Djemil, Toufik; Weinstein, Geoffrey; Jani, Shirish; Enke, Charles; Solberg, Timothy; Flores, Nicholas

    2007-03-15

    Purpose: To report the clinical experience with an electromagnetic treatment target positioning and continuous monitoring system in patients with localized prostate cancer receiving external beam radiotherapy. Methods and Materials: The Calypso System is a target positioning device that continuously monitors the location of three implanted electromagnetic transponders at a rate of 10 Hz. The system was used at five centers to position 41 patients over a full course of therapy. Electromagnetic positioning was compared to setup using skin marks and to stereoscopic X-ray localization of the transponders. Continuous monitoring was performed in 35 patients. Results: The difference between skin mark vs. the Calypso System alignment was found to be >5 mm in vector length in more than 75% of fractions. Comparisons between the Calypso System and X-ray localization showed good agreement. Qualitatively, the continuous motion was unpredictable and varied from persistent drift to transient rapid movements. Displacements {>=}3 and {>=}5 mm for cumulative durations of at least 30 s were observed during 41% and 15% of sessions. In individual patients, the number of fractions with displacements {>=}3 mm ranged from 3% to 87%; whereas the number of fractions with displacements {>=}5 mm ranged from 0% to 56%. Conclusion: The Calypso System is a clinically efficient and objective localization method for positioning prostate patients undergoing radiotherapy. Initial treatment setup can be performed rapidly, accurately, and objectively before radiation delivery. The extent and frequency of prostate motion during radiotherapy delivery can be easily monitored and used for motion management.

  15. Reinforcing of QA/QC programs in radiotherapy departments in Croatia: Results of treatment planning system verification

    SciTech Connect

    Jurković, Slaven; Švabić, Manda; Diklić, Ana; Smilović Radojčić, Đeni; Dundara, Dea; Kasabašić, Mladen; Ivković, Ana; Faj, Dario

    2013-04-01

    Implementation of advanced techniques in clinical practice can greatly improve the outcome of radiation therapy, but it also makes the process much more complex with a lot of room for errors. An important part of the quality assurance program is verification of treatment planning system (TPS). Dosimetric verifications in anthropomorphic phantom were performed in 4 centers where new systems were installed. A total of 14 tests for 2 photon energies and multigrid superposition algorithms were conducted using the CMS XiO TPS. Evaluation criteria as specified in the International Atomic Energy Agency Technical Reports Series (IAEA TRS) 430 were employed. Results of measurements are grouped according to the placement of the measuring point and the beam energy. The majority of differences between calculated and measured doses in the water-equivalent part of the phantom were in tolerance. Significantly more out-of-tolerance values were observed in “nonwater-equivalent” parts of the phantom, especially for higher-energy photon beams. This survey was done as a part of continuous effort to build up awareness of quality assurance/quality control (QA/QC) importance in the Croatian radiotherapy community. Understanding the limitations of different parts of the various systems used in radiation therapy can systematically improve quality as well.

  16. Use of the BrainLAB ExacTrac X-Ray 6D System in Image-Guided Radiotherapy

    SciTech Connect

    Jin, J.-Y. Yin Fangfang; Tenn, Stephen E.; Medin, Paul M.; Solberg, Timothy D.

    2008-07-01

    The ExacTrac X-Ray 6D image-guided radiotherapy (IGRT) system will be described and its performance evaluated. The system is mainly an integration of 2 subsystems: (1) an infrared (IR)-based optical positioning system (ExacTrac) and (2) a radiographic kV x-ray imaging system (X-Ray 6D). The infrared system consists of 2 IR cameras, which are used to monitor reflective body markers placed on the patient's skin to assist in patient initial setup, and an IR reflective reference star, which is attached to the treatment couch and can assist in couch movement with spatial resolution to better than 0.3 mm. The radiographic kV devices consist of 2 oblique x-ray imagers to obtain high-quality radiographs for patient position verification and adjustment. The position verification is made by fusing the radiographs with the simulation CT images using either 3 degree-of-freedom (3D) or 6 degree-of-freedom (6D) fusion algorithms. The position adjustment is performed using the infrared system according to the verification results. The reliability of the fusion algorithm will be described based on phantom and patient studies. The results indicated that the 6D fusion method is better compared to the 3D method if there are rotational deviations between the simulation and setup positions. Recently, the system has been augmented with the capabilities for image-guided positioning of targets in motion due to respiration and for gated treatment of those targets. The infrared markers provide a respiratory signal for tracking and gating of the treatment beam, with the x-ray system providing periodic confirmation of patient position relative to the gating window throughout the duration of the gated delivery.

  17. Use of the BrainLAB ExacTrac X-Ray 6D system in image-guided radiotherapy.

    PubMed

    Jin, Jian-Yue; Yin, Fang-Fang; Tenn, Stephen E; Medin, Paul M; Solberg, Timothy D

    2008-01-01

    The ExacTrac X-Ray 6D image-guided radiotherapy (IGRT) system will be described and its performance evaluated. The system is mainly an integration of 2 subsystems: (1) an infrared (IR)-based optical positioning system (ExacTrac) and (2) a radiographic kV x-ray imaging system (X-Ray 6D). The infrared system consists of 2 IR cameras, which are used to monitor reflective body markers placed on the patient's skin to assist in patient initial setup, and an IR reflective reference star, which is attached to the treatment couch and can assist in couch movement with spatial resolution to better than 0.3 mm. The radiographic kV devices consist of 2 oblique x-ray imagers to obtain high-quality radiographs for patient position verification and adjustment. The position verification is made by fusing the radiographs with the simulation CT images using either 3 degree-of-freedom (3D) or 6 degree-of-freedom (6D) fusion algorithms. The position adjustment is performed using the infrared system according to the verification results. The reliability of the fusion algorithm will be described based on phantom and patient studies. The results indicated that the 6D fusion method is better compared to the 3D method if there are rotational deviations between the simulation and setup positions. Recently, the system has been augmented with the capabilities for image-guided positioning of targets in motion due to respiration and for gated treatment of those targets. The infrared markers provide a respiratory signal for tracking and gating of the treatment beam, with the x-ray system providing periodic confirmation of patient position relative to the gating window throughout the duration of the gated delivery.

  18. Radiotherapy DICOM packet sniffing.

    PubMed

    Ackerly, T; Gesoand, M; Smith, R

    2008-09-01

    The Digital Imaging and Communications in Medicine (DICOM) standard is meant to allow communication of medical images between equipment provided by different vendors, but when two applications do not interact correctly in a multi-vendor environment it is often first necessary to demonstrate non-compliance of either the sender or the receiver before a resolution to the problem can be progressed. Sometimes the only way to do this is to monitor the network communication between the two applications to find out which one is not complying with the DICOM standard. Packet sniffing is a technique of network traffic analysis by passive observation of all information transiting a point on the network, regardless of the specified sender or receiver. DICOM packet sniffing traps and interprets the network communication between two DICOM applications to determine which is non compliant. This is illustrated with reference to three examples, a radiotherapy planning system unable to receive CT data from a particular CT scanner, a radiotherapy simulator unable to print correctly on a DICOM printer, and a PACS unable to respond when queried about what images it has in its archive by a radiotherapy treatment planning system. Additionally in this work it has been proven that it is feasible to extract DICOM images from the intercepted network data. This process can be applied to determine the cause of a DICOM image being rendered differently by the sender and the receiver.

  19. WE-G-BRD-03: Development of a Real-Time Optical Tracking Goggle System (OTGS) for Intracranial Stereotactic Radiotherapy

    SciTech Connect

    Mittauer, K; Yan, G; Lu, B; Barraclough, B; Li, J; Liu, C

    2014-06-15

    Purpose: Optical tracking systems (OTS) are an acceptable alternative to frame-based stereotactic radiotherapy (SRT). However, current surface-based OTS lack the ability to target exclusively rigid/bony anatomical features. We propose a novel marker-based optical tracking goggle system (OTGS) that provides real-time guidance based on the nose/facial bony anatomy. This ongoing study involves the development and characterization of the OTGS for clinical implementation in intracranial stereotactic radiotherapy. Methods: The OTGS consists of eye goggles, a custom thermoplastic nosepiece, and 6 infrared markers pre-attached to the goggles. A phantom and four healthy volunteers were used to evaluate the calibration/registration accuracy, intrafraction accuracy, interfraction reproducibility, and end-to-end accuracy of the OTGS. The performance of the OTGS was compared with that of the frameless SonArray system and cone-beam computed tomography (CBCT) for volunteer and phantom cases, respectively. The performance of the OTGS with commercial immobilization devices and under treatment conditions (i.e., couch rotation and translation range) was also evaluated. Results: The difference in the calibration/registration accuracy of 24 translations or rotation combinations between CBCT and in-house OTS software was within 0.5 mm/0.4°. The mean intrafraction and interfraction accuracy among the volunteers was 0.004+/−0.4mm with −0.09+/−0.5° (n=6,170) and −0.26+/−0.8mm with 0.15+/0.8° (n=11), respectively. The difference in end-to-end accuracy between the OTGS and CBCT was within 1.3 mm/1.1°. The predetermined marker pattern (1) minimized marker occlusions, (2) allowed for continuous tracking for couch angles +/− 90°, (3) and eliminated individual marker misplacement. The device was feasible with open and half masks for immobilization. Conclusion: Bony anatomical localization eliminated potential errors due to facial hair changes and/or soft tissue deformation. The

  20. Magnetic-field-induced dose effects in MR-guided radiotherapy systems: dependence on the magnetic field strength

    NASA Astrophysics Data System (ADS)

    Raaijmakers, A. J. E.; Raaymakers, B. W.; Lagendijk, J. J. W.

    2008-02-01

    Several institutes are currently working on the development of a radiotherapy treatment system with online MR imaging (MRI) modality. The main difference between their designs is the magnetic field strength of the MRI system. While we have chosen a 1.5 Tesla (T) magnetic field strength, the Cross Cancer Institute in Edmonton will be using a 0.2 T MRI scanner and the company Viewray aims to use 0.3 T. The magnetic field strength will affect the severity of magnetic field dose effects, such as the electron return effect (ERE): considerable dose increase at tissue air boundaries due to returning electrons. This paper has investigated how the ERE dose increase depends on the magnetic field strength. Therefore, four situations where the ERE occurs have been simulated: ERE at the distal side of the beam, the lateral ERE, ERE in cylindrical air cavities and ERE in the lungs. The magnetic field comparison values were 0.2, 0.75, 1.5 and 3 T. Results show that, in general, magnetic field dose effects are reduced at lower magnetic field strengths. At the distal side, the ERE dose increase is largest for B = 0.75 T and depends on the irradiation field size for B = 0.2 T. The lateral ERE is strongest for B = 3 T but shows no effect for B = 0.2 T. Around cylindrical air cavities, dose inhomogeneities disappear if the radius of the cavity becomes small relative to the in-air radius of the secondary electron trajectories. At larger cavities (r > 1 cm), dose inhomogeneities exist for all magnetic field strengths. In water-lung-water phantoms, the ERE dose increase takes place at the water-lung transition and the dose decreases at the lung-water transition, but these effects are minimal for B = 0.2 T. These results will contribute to evaluating the trade-off between magnetic field dose effects and image quality of MR-guided radiotherapy systems.

  1. Evaluation of the prognostic value of Okuda, Cancer of the Liver Italian Program, and Japan Integrated Staging systems for hepatocellular carcinoma patients undergoing radiotherapy

    SciTech Connect

    Seong, Jinsil . E-mail: jsseong@yumc.yonsei.ac.kr; Shim, Su Jung; Lee, Ik Jae; Han, Kwang Hyub; Chon, Chae Yoon; Ahn, Sang Hoon

    2007-03-15

    Purpose: The purpose of this study was to compare the validity of staging systems, as well as to identify the staging system with the best prognostic value, in hepatocellular carcinoma (HCC) patients treated with radiotherapy. Methods and Materials: From 1992 to 2003, a total of 305 patients undergoing radiotherapy for HCC were evaluated retrospectively. All patients were classified before radiation therapy by the following systems: tumor-node-metastasis (TNM), Okuda, Cancer of the Liver Italian Program (CLIP), and Japan Integrated Staging (JIS) score. Cumulative survival rates were obtained using the Kaplan-Meier method, and were statistically compared using the log-rank test. Results: Median survival time was 11 months. The 1-, 2-, 3-, 4-, and 5-year survival rates were 45.1%, 24.5%, 14.7%, 10.3%, and 6.4%, respectively. Significant differences in survival were observed between all TNM stages, between CLIP scores 2, 3 and 5, 6, as well as between JIS scores 1, 2, and 2, 3. Conclusions: Among the systems studied, the TNM staging approach appeared to be the best predictor of prognosis. Staging systems that reflect liver disease status (Okuda stage, CLIP, and JIS score) showed limitations in stratifying patients undergoing radiotherapy into different prognostic groups.

  2. WE-G-BRA-06: Application of Systems and Control Theory-Based Hazard Analysis to Radiotherapy

    SciTech Connect

    Pawlicki, T; Samost, A; Leveson, N

    2015-06-15

    Purpose: The process of delivering radiation occurs in a complex socio-technical system heavily reliant on human operators. Furthermore, both humans and software are notoriously challenging to account for in traditional hazard analysis models. High reliability industries such as aviation have approached this problem through using hazard analysis techniques grounded in systems and control theory. The purpose of this work is to apply the Systems Theoretic Accident Model Processes (STAMP) hazard model to radiotherapy. In particular, the System-Theoretic Process Analysis (STPA) approach is used to perform a hazard analysis of a proposed on-line adaptive cranial radiosurgery procedure that omits the CT Simulation step and uses only CBCT for planning, localization, and treatment. Methods: The STPA procedure first requires the definition of high-level accidents and hazards leading to those accidents. From there, hierarchical control structures were created followed by the identification and description of control actions for each control structure. Utilizing these control structures, unsafe states of each control action were created. Scenarios contributing to unsafe control action states were then identified and translated into system requirements to constrain process behavior within safe boundaries. Results: Ten control structures were created for this new CBCT-only process which covered the areas of hospital and department management, treatment design and delivery, and vendor service. Twenty three control actions were identified that contributed to over 80 unsafe states of those control actions resulting in over 220 failure scenarios. Conclusion: The interaction of people, hardware, and software are highlighted through the STPA approach. STPA provides a hierarchical model for understanding the role of management decisions in impacting system safety so that a process design requirement can be traced back to the hazard and accident that it is intended to mitigate. Varian

  3. Post-upgrade testing on a radiotherapy oncology information system with an embedded record and verify system following the IAEA Human Health Report No. 7 recommendations.

    PubMed

    Nyathi, Thulani; Colyer, Christopher; Bhardwaj, Anup Kumar; Rijken, James; Morton, Jason

    2016-06-01

    Record and verify (R&V) systems have proven that their application in radiotherapy clinics leads to a significant reduction in mis-treatments of patients. The purpose of this technical note is to share our experience of acceptance testing, commissioning and setting up a quality assurance programme for the MOSAIQ® oncology information system and R&V system after upgrading from software version 2.41 to 2.6 in a multi-vendor, multi-site environment. Testing was guided primarily by the IAEA Human Report No. 7 recommendations, but complemented by other departmental workflow specific tests. To the best of our knowledge, this is the first time successful implementation of the IAEA Human Health Report Series No. 7 recommendations have been reported in the literature.

  4. [Possibilities of systemic radiotherapy with high-purity 89Sr chloride in the treatment of bone metastases].

    PubMed

    Fomin, D K; Tararukhina, O B; Nazarov, A A

    2012-01-01

    To study the efficiency of treatment via single administration of high-purity 89Sr chloride in the standard activity of 150 MBq for pain syndrome in patients with multiple bone metastases. The authors carried out clinical trials of high-purity 89Sr chloride used to treat 30 patients with multiple bone metastases from cancers at various sites. The results of treatment were analyzed in 30 patients with multiple bone metastases, who had received systemic radiation therapy with high-purity 89Sr chloride in the standard activity of 150 MBq. These were assessed using some indicators: the intensity of pain syndrome and the blood concentrations of hemoglobin, leukocytes, and platelets. There was evidence for the use of high-purity 89Sr chloride in the therapy of patients with cancer at various sites with multiple bone metastases. The major indicators (pain syndrome, the blood concentrations of hemoglobin, leukocytes, and platelets) were compared before and after the treatment. These were also compared with those obtained with the use of usual 89Sr chloride. The therapeutic action of high-purity 89Sr chloride is comparable with that of 89Sr chloride in the standard activity; moreover, the analgesic effect of high-purity 89Sr chloride is being significantly higher. It has less significant myelotoxic activity than usual 89Sr chloride. High-purity 89Sr chloride is an effective radiopharmaceutical agent and may be used for systemic radiotherapy in patients with multiple bone metastatic lesion.

  5. Discrete and continuous description of a three-dimensional scene for quality control of radiotherapy treatment planning systems

    NASA Astrophysics Data System (ADS)

    Denis, Eloise; Guédon, JeanPierre; Beaumont, Stéphane; Normand, Nicolas

    2006-03-01

    Quality Control (QC) procedures are mandatory to achieve accuracy in radiotherapy treatments. For that purpose, classical methods generally use physical phantoms that are acquired by the system in place of the patient. In this paper, the use of digital test objects (DTO) replace the actual acquisition1. A DTO is a 3D scene description composed of simple and complex shapes from which discrete descriptions can be obtained. For QC needs, both the DICOM format (for Treatment Planning System (TPS) inputs) as well as continuous descriptions are required. The aim of this work is to define an equivalence model between a continuous description of the three dimensional (3D) scene used to define the DTO, and the DTO characteristics. The purpose is to have an XML- DTO description in order to compute discrete calculations from a continuous description. The defined structure allows also to obtain the three dimensional matrix of the DTO and then the series of slices stored in the DICOM format. Thus, it is shown how possibly design DTO for quality control in CT simulation and dosimetry.

  6. Dosimetric and delivery efficiency investigation for treating hepatic lesions with a MLC-equipped robotic radiosurgery–radiotherapy combined system

    SciTech Connect

    Jin, Lihui Price, Robert A.; Wang, Lu; Meyer, Joshua; Fan, James; Charlie Ma, Chang Ming

    2016-02-15

    Purpose: The CyberKnife M6 (CK-M6) Series introduced a multileaf collimator (MLC) for extending its capability from stereotactic radiosurgery/stereotactic radiotherapy (SBRT) to conventionally fractionated radiotherapy. This work is to investigate the dosimetric quality of plans that are generated using MLC-shaped beams on the CK-M6, as well as their delivery time, via comparisons with the intensity modulated radiotherapy plans that were clinically used on a Varian Linac for treating hepatic lesions. Methods: Nine patient cases were selected and divided into three groups with three patients in each group: (1) the group-one patients were treated conventionally (25 fractions); (2) the group-two patients were treated with SBRT-like hypofractionation (5 fractions); and (3) the group-three patients were treated similar to group-one patients, but with two planning target volumes (PTVs) and two different prescription dose levels correspondingly. The clinically used plans were generated on the ECLIPSE treatment planning system (TPS) and delivered on a Varian Linac (E-V plans). The multiplan (MP) TPS was used to replan these clinical cases with the MLC as the beam device for the CK-M6 (C-M plans). After plans were normalized to the same PTV dose coverage, comparisons between the C-M and E-V plans were performed based on D{sub 99%} (percentage of prescription dose received by 99% of the PTV), D{sub 0.1cm{sup 3}} (the percentage of prescription dose to 0.1 cm{sup 3} of the PTV), and doses received by critical structures. Then, the delivery times for the C-M plans will be obtained, which are the MP TPS generated estimations assuming having an imaging interval of 60 s. Results: The difference in D{sub 99%} between C-M and E-V plans is +0.6% on average (+ or − indicating a higher or lower dose from C-M plans than from E-V plans) with a range from −4.1% to +3.8%, and the difference in D{sub 0.1cm{sup 3}} was −1.0% on average with a range from −5.1% to +2.9%. The PTV

  7. SU-E-T-608: Performance Comparison of Four Commercial Treatment Planning Systems Applied to Intensity-Modulated Radiotherapy

    SciTech Connect

    Cao, Y; Li, R; Chi, Z

    2014-06-01

    Purpose: To compare the performances of four commercial treatment planning systems (TPS) used for the intensity-modulated radiotherapy (IMRT). Methods: Ten patients of nasopharyngeal (4 cases), esophageal (3 cases) and cervical (3 cases) cancer were randomly selected from a 3-month IMRT plan pool at one radiotherapy center. For each patient, four IMRT plans were newly generated by using four commercial TPS (Corvus, Monaco, Pinnacle and Xio), and then verified with Matrixx (two-dimensional array/IBA Company) on Varian23EX accelerator. A pass rate (PR) calculated from the Gamma index by OminiPro IMRT 1.5 software was evaluated at four plan verification standards (1%/1mm, 2%/2mm, 3%/3mm, 4%/4mm and 5%/5mm) for each treatment plan. Overall and multiple pairwise comparisons of PRs were statistically conducted by analysis of covariance (ANOVA) F and LSD tests among four TPSs. Results: Overall significant (p>0.05) differences of PRs were found among four TPSs with F test values of 3.8 (p=0.02), 21.1(>0.01), 14.0 (>0.01), 8.3(>0.01) at standards of 1%/1mm to 4%/4mm respectively, except at 5%/5mm standard with 2.6 (p=0.06). All means (standard deviation) of PRs at 3%/3mm of 94.3 ± 3.3 (Corvus), 98.8 ± 0.8 (Monaco), 97.5± 1.7 (Pinnacle), 98.4 ± 1.0 (Xio) were above 90% and met clinical requirement. Multiple pairwise comparisons had not demonstrated a consistent low or high pattern on either TPS. Conclusion: Matrixx dose verification results show that the validation pass rates of Monaco and Xio plans are relatively higher than those of the other two; Pinnacle plan shows slight higher pass rate than Corvus plan; lowest pass rate was achieved by the Corvus plan among these four kinds of TPS.

  8. Dosimetric comparison between two MLC systems commonly used for stereotactic radiosurgery and radiotherapy: a Monte Carlo and experimental study.

    PubMed

    Asnaashari, K; Chow, James C L; Heydarian, Mostafa

    2013-06-01

    In this work dosimetric parameters of two multi-leaf collimator (MLC) systems, namely the beam modulator (BM), which is the MLC commercial name for Elekta "Synergy S" linear accelerator and Radionics micro-MLC (MMLC), are compared using measurements and Monte Carlo simulations. Dosimetric parameters, such as percentage depth doses (PDDs), in-plane and cross-plane dose profiles, and penumbras for different depths and field sizes of the 6 MV photon beams were measured using ionization chamber and a water tank. The collimator leakages were measured using radiographic films. MMLC and BM were modeled using the EGSnrc-based BEAMnrc Monte Carlo code and above dosimetric parameters were calculated. The energy fluence spectra for the two MLCs were also determined using the BEAMnrc and BEAMDP. Dosimetric parameters of the two MLCs were similar, except for penumbras. Leaf-side and leaf-end 80-20% dose penumbras at 10 cm depth for a 10×10 cm(2) field size were 4.8 and 5.1mm for MMLC and 5.3 mm and 6.3 mm for BM, respectively. Both Radionics MMLC and Elekta BM can be used effectively based on their dosimetric characteristics for stereotactic radiosurgery and radiotherapy, although the former showed slightly sharper dose penumbra especially in the leaf-end direction. Copyright © 2012 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  9. Phase unwrapping algorithms for use in a true real-time optical body sensor system for use during radiotherapy.

    PubMed

    Parkhurst, James; Price, Gareth; Sharrock, Phil; Moore, Christopher

    2011-12-10

    An evaluation of the suitability of eight existing phase unwrapping algorithms to be used in a real-time optical body surface sensor based on Fourier fringe profilometry is presented. The algorithms are assessed on both the robustness of the results they give and their speed of execution. The algorithms are evaluated using four sets of real human body surface data, each containing five-hundred frames, obtained from patients undergoing radiotherapy, where fringe discontinuity is significant. We also present modifications to an existing algorithm, noncontinuous quality-guided path algorithm (NCQUAL), in order to decrease its execution time by a factor of 4 to make it suitable for use in a real-time system. The results obtained from the modified algorithm are compared with those of the existing algorithms. Three suitable algorithms were identified: two-stage noncontinuous quality-guided path algorithm (TSNCQUAL)-the modified algorithm presented here-for online processing and Flynn's minimum discontinuity algorithm (FLYNN) and preconditioned conjugate gradient method (PCG) algorithms for enhanced accuracy in off-line processing.

  10. Development of a prototype of the tele-localisation system in radiotherapy using personal digital assistant via wireless communication.

    PubMed

    Wu, Vincent Wing-Cheung; Tang, Fuk-hay; Cheung, Wai-kwan; Chan, Kit-chi

    2013-02-01

    In localisation of radiotherapy treatment field, the oncologist is present at the simulator to approve treatment details produced by the therapist. Problems may arise if the oncologist is not available and the patient requires urgent treatment. The development of a tele-localisation system is a potential solution, where the oncologist uses a personal digital assistant (PDA) to localise the treatment field on the image sent from the simulator through wireless communication and returns the information to the therapist after his or her approval. Our team developed the first tele-localisation prototype, which consisted of a server workstation (simulator) for the administration of digital imaging and communication in medicine localisation images including viewing and communication with the PDA via a Wi-Fi network; a PDA (oncologist's site) installed with the custom-built programme that synchronises with the server workstation and performs treatment field editing. Trial tests on accuracy and speed of the prototype system were conducted on 30 subjects with the treatment regions covering the neck, skull, chest and pelvis. The average time required in performing the localisation using the PDA was less than 1.5 min, with the blocked field longer than the open field. The transmission speed of the four treatment regions was similar. The average physical distortion of the images was within 4.4% and the accuracy of field size indication was within 5.3%. Compared with the manual method, the tele-localisation system presented with an average deviation of 5.5%. The prototype system fulfilled the planned objectives of tele-localisation procedure with reasonable speed and accuracy.

  11. Fractionated stereotactic radiotherapy for skull base tumors: analysis of treatment accuracy using a stereotactic mask fixation system

    PubMed Central

    2010-01-01

    Background To assess the accuracy of fractionated stereotactic radiotherapy (FSRT) using a stereotactic mask fixation system. Patients and Methods Sixteen patients treated with FSRT were involved in the study. A commercial stereotactic mask fixation system (BrainLAB AG) was used for patient immobilization. Serial CT scans obtained before and during FSRT were used to assess the accuracy of patient immobilization by comparing the isocenter position. Daily portal imaging were acquired to establish day to day patient position variation. Displacement errors along the different directions were calculated as combination of systematic and random errors. Results The mean isocenter displacements based on localization and verification CT imaging were 0.1 mm (SD 0.3 mm) in the lateral direction, 0.1 mm (SD 0.4 mm) in the anteroposterior, and 0.3 mm (SD 0.4 mm) in craniocaudal direction. The mean 3D displacement was 0.5 mm (SD 0.4 mm), being maximum 1.4 mm. No significant differences were found during the treatment (P = 0.4). The overall isocenter displacement as calculated by 456 anterior and lateral portal images were 0.3 mm (SD 0.9 mm) in the mediolateral direction, -0.2 mm (SD 1 mm) in the anteroposterior direction, and 0.2 mm (SD 1.1 mm) in the craniocaudal direction. The largest displacement of 2.7 mm was seen in the cranio-caudal direction, with 95% of displacements < 2 mm in any direction. Conclusions The results indicate that the setup error of the presented mask system evaluated by CT verification scans and portal imaging are minimal. Reproducibility of the isocenter position is in the best range of positioning reproducibility reported for other stereotactic systems. PMID:20070901

  12. Development of a four-dimensional image-guided radiotherapy system with a gimbaled X-ray head

    SciTech Connect

    Kamino, Yuichiro . E-mail: daisaku_horiuchi@mhi.co.jp; Takayama, Kenji; Kokubo, Masaki; Narita, Yuichiro; Hirai, Etsuro; Kawawda, Noriyuki; Mizowaki, Takashi; Nagata, Yasushi; Nishidai, Takehiro; Hiraoka, Masahiro

    2006-09-01

    Purpose: To develop and evaluate a new four-dimensional image-guided radiotherapy system, which enables precise setup, real-time tumor tracking, and pursuit irradiation. Methods and Materials: The system has an innovative gimbaled X-ray head that enables small-angle ({+-}2.4{sup o}) rotations (pan and tilt) along the two orthogonal gimbals. This design provides for both accurate beam positioning at the isocenter by actively compensating for mechanical distortion and quick pursuit of the target. The X-ray head is composed of an ultralight C-band linear accelerator and a multileaf collimator. The gimbaled X-ray head is mounted on a rigid O-ring structure with an on-board imaging subsystem composed of two sets of kilovoltage X-ray tubes and flat panel detectors, which provides a pair of radiographs, cone beam computed tomography images useful for image guided setup, and real-time fluoroscopic monitoring for pursuit irradiation. Results: The root mean square accuracy of the static beam positioning was 0.1 mm for 360{sup o} of O-ring rotation. The dynamic beam response and positioning accuracy was {+-}0.6 mm for a 0.75 Hz, 40-mm stroke and {+-}0.4 mm for a 2.0 Hz, 8-mm stroke. The quality of the images was encouraging for using the tomography-based setup. Fluoroscopic images were sufficient for monitoring and tracking lung tumors. Conclusions: Key functions and capabilities of our new system are very promising for precise image-guided setup and for tracking and pursuit irradiation of a moving target.

  13. Modeling of body tissues for Monte Carlo simulation of radiotherapy treatments planned with conventional x-ray CT systems.

    PubMed

    Kanematsu, Nobuyuki; Inaniwa, Taku; Nakao, Minoru

    2016-07-07

    In the conventional procedure for accurate Monte Carlo simulation of radiotherapy, a CT number given to each pixel of a patient image is directly converted to mass density and elemental composition using their respective functions that have been calibrated specifically for the relevant x-ray CT system. We propose an alternative approach that is a conversion in two steps: the first from CT number to density and the second from density to composition. Based on the latest compilation of standard tissues for reference adult male and female phantoms, we sorted the standard tissues into groups by mass density and defined the representative tissues by averaging the material properties per group. With these representative tissues, we formulated polyline relations between mass density and each of the following; electron density, stopping-power ratio and elemental densities. We also revised a procedure of stoichiometric calibration for CT-number conversion and demonstrated the two-step conversion method for a theoretically emulated CT system with hypothetical 80 keV photons. For the standard tissues, high correlation was generally observed between mass density and the other densities excluding those of C and O for the light spongiosa tissues between 1.0 g cm(-3) and 1.1 g cm(-3) occupying 1% of the human body mass. The polylines fitted to the dominant tissues were generally consistent with similar formulations in the literature. The two-step conversion procedure was demonstrated to be practical and will potentially facilitate Monte Carlo simulation for treatment planning and for retrospective analysis of treatment plans with little impact on the management of planning CT systems.

  14. Modeling of body tissues for Monte Carlo simulation of radiotherapy treatments planned with conventional x-ray CT systems

    NASA Astrophysics Data System (ADS)

    Kanematsu, Nobuyuki; Inaniwa, Taku; Nakao, Minoru

    2016-07-01

    In the conventional procedure for accurate Monte Carlo simulation of radiotherapy, a CT number given to each pixel of a patient image is directly converted to mass density and elemental composition using their respective functions that have been calibrated specifically for the relevant x-ray CT system. We propose an alternative approach that is a conversion in two steps: the first from CT number to density and the second from density to composition. Based on the latest compilation of standard tissues for reference adult male and female phantoms, we sorted the standard tissues into groups by mass density and defined the representative tissues by averaging the material properties per group. With these representative tissues, we formulated polyline relations between mass density and each of the following; electron density, stopping-power ratio and elemental densities. We also revised a procedure of stoichiometric calibration for CT-number conversion and demonstrated the two-step conversion method for a theoretically emulated CT system with hypothetical 80 keV photons. For the standard tissues, high correlation was generally observed between mass density and the other densities excluding those of C and O for the light spongiosa tissues between 1.0 g cm-3 and 1.1 g cm-3 occupying 1% of the human body mass. The polylines fitted to the dominant tissues were generally consistent with similar formulations in the literature. The two-step conversion procedure was demonstrated to be practical and will potentially facilitate Monte Carlo simulation for treatment planning and for retrospective analysis of treatment plans with little impact on the management of planning CT systems.

  15. A comparison of two systems of patient immobilization for prostate radiotherapy

    PubMed Central

    2014-01-01

    Background Reproducibility of different immobilization systems, which may affect set-up errors, remains uncertain. Immobilization systems and their corresponding set-up errors influence the clinical target volume to planning target volume (CTV-PTV) margins and thus may result in undesirable treatment outcomes. This study compared the reproducibility of patient positioning with Hipfix system and whole body alpha cradle with respect to localized prostate cancer and investigated the existing CTV-PTV margins in the clinical oncology departments of two hospitals. Methods Forty sets of data of patients with localized T1-T3 prostate cancer were randomly selected from two regional hospitals, with 20 patients immobilized by a whole-body alpha cradle system and 20 by a thermoplastic Hipfix system. Seven sets of the anterior-posterior (AP), cranial-caudal (CC) and medial-lateral (ML) deviations were collected from each patient. The reproducibility of patient positioning within the two hospitals was compared using a total vector error (TVE) parameter. In addition, CTV-PTV margins were computed using van Herk’s formula. The resulting values were compared to the current CTV-PTV margins in both hospitals. Results The TVE values were 5.1 and 2.8 mm for the Hipfix and the whole-body alpha cradle systems respectively. TVE associated with the whole-body alpha cradle system was found to be significantly less than the Hipfix system (p < 0.05). The CC axis in the Hipfix system attained the highest frequency of large (23.6%) and serious (7.9%) set-up errors. The calculated CTV to PTV margin was 8.3, 1.9 and 2.3 mm for the Hipfix system, and 2.1, 3.4 and 1.8 mm for the whole body alpha cradle in CC, ML and AP axes respectively. All but one (CC axis using Hipfix) margin calculated did not exceed the corresponding hospital protocol. The whole body alpha cradle system was found to be significantly better than the Hipfix system in terms of reproducibility (p < 0.05), especially

  16. Statistical Determination of the Gating Windows for Respiratory-Gated Radiotherapy Using a Visible Guiding System

    PubMed Central

    Oh, Se An; Yea, Ji Woon

    2016-01-01

    Respiratory-gated radiation therapy (RGRT) is used to minimize the radiation dose to normal tissue in lung-cancer patients. Although determining the gating window in the respiratory phase of patients is important in RGRT, it is not easy. Our aim was to determine the optimal gating window when using a visible guiding system for RGRT. Between April and October 2014, the breathing signals of 23 lung-cancer patients were recorded with a real-time position management (RPM) respiratory gating system (Varian, USA). We performed statistical analysis with breathing signals to find the optimal gating window for guided breathing in RGRT. When we compared breathing signals before and after the breathing training, 19 of the 23 patients showed statistically significant differences (p < 0.05). The standard deviation of the respiration signals after breathing training was lowest for phases of 30%–70%. The results showed that the optimal gating window in RGRT is 40% (30%–70%) with respect to repeatability for breathing after respiration training with the visible guiding system. RGRT was performed with the RPM system to confirm the usefulness of the visible guiding system. The RPM system and our visible guiding system improve the respiratory regularity, which in turn should improve the accuracy and efficiency of RGRT. PMID:27228097

  17. Statistical Determination of the Gating Windows for Respiratory-Gated Radiotherapy Using a Visible Guiding System.

    PubMed

    Oh, Se An; Yea, Ji Woon; Kim, Sung Kyu

    2016-01-01

    Respiratory-gated radiation therapy (RGRT) is used to minimize the radiation dose to normal tissue in lung-cancer patients. Although determining the gating window in the respiratory phase of patients is important in RGRT, it is not easy. Our aim was to determine the optimal gating window when using a visible guiding system for RGRT. Between April and October 2014, the breathing signals of 23 lung-cancer patients were recorded with a real-time position management (RPM) respiratory gating system (Varian, USA). We performed statistical analysis with breathing signals to find the optimal gating window for guided breathing in RGRT. When we compared breathing signals before and after the breathing training, 19 of the 23 patients showed statistically significant differences (p < 0.05). The standard deviation of the respiration signals after breathing training was lowest for phases of 30%-70%. The results showed that the optimal gating window in RGRT is 40% (30%-70%) with respect to repeatability for breathing after respiration training with the visible guiding system. RGRT was performed with the RPM system to confirm the usefulness of the visible guiding system. The RPM system and our visible guiding system improve the respiratory regularity, which in turn should improve the accuracy and efficiency of RGRT.

  18. Radiotherapy in the UK

    SciTech Connect

    Ramsay, S.

    1993-10-09

    What is wrong with radiation treatment in the UK Is it bad practice or merely bad publicity Between 1982 and 1991, 1,000 patients receiving isocentric radiation therapy at the North Staffordshire Royal Infirmary received a substantial underdose of radiation; the clinical report on this incident was published last week. The operator had been using a correction factor for tumor-to-skin distance, unaware that this factor had already been applied by the computer system. Although the report pointed out that it is not surprising that the clinicians were not alerted to the undertreatment, is also noted that there were no resources at the hospital to audit the outcome of radiotherapy.

  19. Reduced rectal toxicity with ultrasound-based image guided radiotherapy using BAT (B-mode acquisition and targeting system) for prostate cancer.

    PubMed

    Bohrer, Markus; Schröder, Peter; Welzel, Grit; Wertz, Hansjörg; Lohr, Frank; Wenz, Frederik; Mai, Sabine Kathrin

    2008-12-01

    To evaluate the effect of image guided radiotherapy with stereotactic ultrasound BAT (B-mode acquisition and targeting system) on rectal toxicity in conformal radiotherapy of prostate cancer. 42 sequential patients with prostate cancer undergoing radiotherapy before and after the introduction of BAT were included. Planning computed tomography (CT) was performed with empty rectum and moderately filled bladder. The planning target volume (PTV) included the prostate and seminal vesicles with a safety margin of 1.5 cm in anterior and lateral direction. In posterior direction the anterior 1/3 of the rectum circumference were included. Total dose was 66 Gy and a boost of 4 Gy excluding the seminal vesicles. 22 patients (BAT group) were treated with daily stereotactic ultrasound positioning, for the other 20 patients (NoBAT group) an EPID (electronic portal imaging device) was performed once a week. Acute and late genito-urinary (GU) and rectal toxicity and PSA values were evaluated after 1.5, 3, 6, 9 and 12 months. The total median follow up of toxicity was 3 years in the BAT group and 4 years in the NoBAT group. In the NoBAT group significant more rectal toxicity occurred, while in GU toxicity no difference was seen. Two patients in the NoBAT group showed late rectal toxicity grade 3, no toxicity>grade 2 occurred in the BAT group. There was no significant difference in PSA reduction between the groups. Without BAT significant more acute and a trend to more late rectal toxicity was found. With regard to dose escalation this aspect is currently evaluated with a larger number of patients using intensity-modulated radiotherapy (IMRT).

  20. Systemic analysis of different colorectal cancer cell lines and TCGA datasets identified IGF-1R/EGFR-PPAR-CASPASE axis as important indicator for radiotherapy sensitivity.

    PubMed

    Chen, Lin; Zhu, Zhe; Gao, Wei; Jiang, Qixin; Yu, Jiangming; Fu, Chuangang

    2017-09-05

    Insulin-like growth factor 1 receptor (IGF-1R) is proved to contribute the development of many types of cancers. But, little is known about its roles in radio-resistance of colorectal cancer (CRC). Here, we demonstrated that low IGF-1R expression value was associated with the better radiotherapy sensitivity of CRC. Besides, through Quantitative Real-time PCR (qRT-PCR), the elevated expression value of epidermal growth factor receptor (EGFR) was observed in CRC cell lines (HT29, RKO) with high radio-sensitivity compared with those with low sensitivity (SW480, LOVO). The irradiation induced apoptosis rates of wild type and EGFR agonist (EGF) or IGF-1R inhibitor (NVP-ADW742) treated HT29 and SW480 cells were quantified by flow cytometry. As a result, the apoptosis rate of EGF and NVP-ADW742 treated HT29 cells was significantly higher than that of those wild type ones, which indicated that high EGFR and low IGF-1R expression level in CRC was associated with the high sensitivity to radiotherapy. We next conducted systemic bioinformatics analysis of genome-wide expression profiles of CRC samples from the Cancer Genome Atlas (TCGA). Differential expression analysis between IGF-1R and EGFR abnormal CRC samples, i.e. CRC samples with higher IGF-1R and lower EGFR expression levels based on their median expression values, and the rest of CRC samples identified potential genes contribute to radiotherapy sensitivity. Functional enrichment of analysis of those differential expression genes (DEGs) in the Database for Annotation, Visualization and Integrated Discovery (DAVID) indicated PPAR signaling pathway as an important pathway for the radio-resistance of CRC. Our study identified the potential biomarkers for the rational selection of radiotherapy for CRC patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Construction of the radiation oncology teaching files system for charged particle radiotherapy.

    PubMed

    Masami, Mukai; Yutaka, Ando; Yasuo, Okuda; Naoto, Takahashi; Yoshihisa, Yoda; Hiroshi, Tsuji; Tadashi, Kamada

    2013-01-01

    Our hospital started the charged particle therapy since 1996. New institutions for charged particle therapy are planned in the world. Our hospital are accepting many visitors from those newly planned medical institutions and having many opportunities to provide with the training to them. Based upon our experiences, we have developed the radiation oncology teaching files system for charged particle therapy. We adopted the PowerPoint of Microsoft as a basic framework of our teaching files system. By using our export function of the viewer any physician can create teaching files easily and effectively. Now our teaching file system has 33 cases for clinical and physics contents. We expect that we can improve the safety and accuracy of charged particle therapy by using our teaching files system substantially.

  2. [Radiotherapy of bone metastases].

    PubMed

    Thureau, S; Vieillard, M-H; Supiot, S; Lagrange, J-L

    2016-09-01

    Radiotherapy plays a major role in palliative treatment of bone metastases. Recent developments of stereotactic radiotherapy and intensity modulated radiation therapy give the possibility to treat oligometastatic diseases. The objective of this paper is to report indications and treatment modalities of radiotherapy in these situations.

  3. Assessment of Spatial Uncertainties in the Radiotherapy Process With the Novalis System

    SciTech Connect

    Hayashi, Naoki Obata, Yasunori; Uchiyama, Yukio; Mori, Yoshimasa; Hashizume, Chisa; Kobayashi, Tatsuya

    2009-10-01

    Purpose: The purpose of this study was to evaluate the accuracy of a new version of the ExacTrac X-ray (ETX) system with statistical analysis retrospectively in order to determine the tolerance of systematic components of spatial uncertainties with the Novalis system. Methods and Materials: Three factors of geometrical accuracy related to the ETX system were evaluated by phantom studies. First, location dependency of the detection ability of the infrared system was evaluated. Second, accuracy of the automated calculation by the image fusion algorithm in the patient registration software was evaluated. Third, deviation of the coordinate scale between the ETX isocenter and the mechanical isocenter was evaluated. From the values of these examinations and clinical experiences, the total spatial uncertainty with the Novalis system was evaluated. Results: As to the location dependency of the detection ability of the infrared system, the detection errors between the actual position and the detected position were 1% in translation shift and 0.1{sup o} in rotational angle, respectively. As to the accuracy of patient verification software, the repeatability and the coincidence of the calculation value by image fusion were good when the contrast of the X-ray image was high. The deviation of coordinates between the ETX isocenter and the mechanical isocenter was 0.313 {+-} 0.024 mm, in a suitable procedure. Conclusions: The spatial uncertainty will be less than 2 mm when suitable treatment planning, optimal patient setup, and daily quality assurance for the Novalis system are achieved in the routine workload.

  4. [Head and neck adaptive radiotherapy].

    PubMed

    Graff, P; Huger, S; Kirby, N; Pouliot, J

    2013-10-01

    Onboard volumetric imaging systems can provide accurate data of the patient's anatomy during a course of head and neck radiotherapy making it possible to assess the actual delivered dose and to evaluate the dosimetric impact of complex daily positioning variations and gradual anatomic changes such as geometric variations of tumors and normal tissues or shrinkage of external contours. Adaptive radiotherapy is defined as the correction of a patient's treatment planning to adapt for individual variations observed during treatment. Strategies are developed to selectively identify patients that require replanning because of an intolerable dosimetric drift. Automated tools are designed to limit time consumption. Deformable image registration algorithms are the cornerstones of these strategies, but a better understanding of their limits of validity is required before adaptive radiotherapy can be safely introduced to daily practice. Moreover, strict evaluation of the clinical benefits is yet to be proven.

  5. Can a commercial gel dosimetry system be used to verify stereotactic spinal radiotherapy treatment dose distributions?

    NASA Astrophysics Data System (ADS)

    Kairn, T.; Asena, A.; Crowe, S. B.; Livingstone, A.; Papworth, D.; Smith, S.; Sutherland, B.; Sylvander, S.; Franich, R. D.; Trapp, J. V.

    2017-05-01

    This study investigated the use of the TruView xylenol-orange-based gel and VISTA optical CT scanner (both by Modus Medical Inc, London, Canada), for use in verifying the accuracy of planned dose distributions for hypo-fractionated (stereotactic) vertebral treatments. Gel measurements were carried out using three stereotactic vertebral treatments and compared with planned doses calculated using the Eclipse treatment planning system (Varian Medical Systems, Palo Alto, USA) as well as with film measurements made using Gafchromic EBT3 film (Ashland Inc, Covington, USA), to investigate the accuracy of the gel system. The gel was calibrated with reference to a moderate-dose gradient region in one of the gel samples. Generally, the gel measurements were able to approximate the close agreement between the doses calculated by the treatment planning system and the doses measured using film (which agreed with each other within 2%), despite lower resolution and bit depth. Poorer agreement was observed when the dose delivered to the gel exceeded the range of doses delivered in the calibration region. This commercial gel dosimetry system may be used to verify hypo-fractionated treatments of vertebral targets, although separate gel calibration measurements are recommended.

  6. Technical Note: Validation and implementation of a wireless transponder tracking system for gated stereotactic ablative radiotherapy of the liver.

    PubMed

    James, Joshua; Cetnar, Ashley; Dunlap, Neal E; Huffaker, Corinna; Nguyen, Vi Nhan; Potts, Melissa; Wang, Brian

    2016-06-01

    Tracking soft-tissue targets has recently been cleared as a new application of Calypso, an electromagnetic wireless transponder tracking system, allowing for gated treatment of the liver based on the motion of the target volume itself. The purpose of this study is to describe the details of validating the Calypso system for wireless transponder tracking of the liver and to present the clinical workflow for using it to deliver gated stereotactic ablative radiotherapy (SABR). A commercial 3D diode array motion system was used to evaluate the dynamic tracking accuracy of Calypso when tracking continuous large amplitude motion. It was then used to perform end-to-end tests to evaluate the dosimetric accuracy of gated beam delivery for liver SABR. In addition, gating limits were investigated to determine how large the gating window can be while still maintaining dosimetric accuracy. The gating latency of the Calypso system was also measured using a customized motion phantom. The average absolute difference between the measured and expected positional offset was 0.3 mm. The 2%/2 mm gamma pass rates for the gated treatment delivery were greater than 97%. When increasing the gating limits beyond the known extent of planned motion, the gamma pass rates decreased as expected. The 2%/2 mm gamma pass rate for a 1, 2, and 3 mm increase in gating limits was measured to be 97.8%, 82.9%, and 61.4%, respectively. The average gating latency was measured to be 63.8 ms for beam-hold and 195.8 ms for beam-on. Four liver patients with 17 total fractions have been successfully treated at our institution. Wireless transponder tracking was validated as a dosimetrically accurate way to provide gated SABR of the liver. The dynamic tracking accuracy of the Calypso system met manufacturer's specification, even for continuous large amplitude motion that can be encountered when tracking liver tumors close to the diaphragm. The measured beam-hold gating latency was appropriate for targets that

  7. [Staging 915 cases of nasopharyngeal carcinoma after simple radical radiotherapy--checkout of Fuzhou staging system (1992)].

    PubMed

    Gao, Jian-Ming; Zeng, Yi-Xin; Cui, Nian-Ji; Lu, Tai-Xiang; Zhao, Chong; Xia, Yun-Fei; Ma, Jun; Xie, Fang-Yun

    2005-10-01

    Along with the development of treatments, different tumor staging systems are coexisted and have been modified. This study was to validate the rationality of the Fuzhou staging system (1992) of nasopharyngeal carcinoma (NPC), and to provide some suggestions. A total of 915 NPC patients received radical radiotherapy alone in Cancer Center of Sun Yat-sen University from Jan. 1997 to Dec. 1998. The 1-, 3-, and 5-year follow-up rates were 98.7%, 95.2%, and 91.7%, respectively. The survival data were analyzed with Life table, Cox regression, Kaplan-Meier, and log-rank methods. The 1-, 3-, and 5-year overall survival rates of the 915 patients were 87.69%, 72.73%, and 64.44%; the 1-, 3-, and 5-year disease-freely survival rates were 86.87%, 69.72%, and 58.33%, respectively. Cox regression analysis showed that the 5-year survival statuses of the 915 patients were significantly correlated with their age and the tumor stage classified by the Fuzhou staging system (1992); the 5-year survival statuses of the 803 patients no more than 60 years old were only significantly correlated with tumor stage, and had no correlation with their age. Life table analysis validated that the tumor stage classified by Fuzhou staging system (1992) can roughly predict the prognosis, but the difference between the 5-year survival rates of stage I and II patients was not significant. Kaplan-Meier analysis showed no significant difference between survival statuses of stage T1 and T2 patients when adjusted by N classification. Therefore, we adjusted stage T2 without parapharyngeal space invasion to stage T1, stage T3 with carotid vagina invasion to stage T2, stage T4 with paranasal sinus involvement to stage T3, stage T3 with cranial nerve injury to stage T4, and stage N1 with bilateral lymph nodes involvement to stage N2. After the modifications, the differences among stage I to IVa, stage T1 to T4 (adjusted by N stage), or stage N0 to N3 (adjusted by T stage) were significant. Taking the impact of

  8. Online planning and delivery technique for radiotherapy of spinal metastases using cone-beam CT: Image quality and system performance

    SciTech Connect

    Letourneau, Daniel . E-mail: daniel.letourneau@rmp.uhn.on.ca; Wong, Rebecca; Moseley, Douglas; Sharpe, Michael B.; Ansell, Stephen B.Sc.; Gospodarowicz, Mary; Jaffray, David A.

    2007-03-15

    Purpose: To assess the feasibility of an online strategy for palliative radiotherapy (RT) of spinal bone metastasis, which integrates imaging, planning, and treatment delivery in a single step at the treatment unit. The technical challenges of this approach include cone-beam CT (CBCT) image quality for target definition, online planning, and efficient process integration. Methods and Materials: An integrated imaging, planning, and delivery system was constructed and tested with phantoms. The magnitude of CBCT image artifacts following the use of an antiscatter grid and a nonlinear scatter correction was quantified using phantom data and images of patients receiving conventional palliative RT of the spine. The efficacy of online planning was then assessed using corrected CBCT images. Testing of the complete process was performed on phantoms with assessment of timing and dosimetric accuracy. Results: The use of image corrections reduced the cupping artifact from 30% to 4.5% on CBCT images of a body phantom and improved the accuracy of CBCT numbers (water: {+-} 20 Hounsfield unit [HU], and lung and bone: to within {+-} 130 HU). Bony anatomy was clearly visible and was deemed sufficient for target definition. The mean total time (n = 5) for application of the online approach was 23.1 min. Image-guided dose placement was assessed using radiochromic film measurements with good agreement (within 5% of dose difference and 2 mm of distance to agreement). Conclusions: The technical feasibility of CBCT-guided online planning and delivery for palliative single treatment has been demonstrated. The process was performed in one session equivalent to an initial treatment slot (<30 min) with dosimetric accuracy satisfying accepted RT standards.

  9. Human factors and systems engineering approach to patient safety for radiotherapy.

    PubMed

    Rivera, A Joy; Karsh, Ben-Tzion

    2008-01-01

    The traditional approach to solving patient safety problems in healthcare is to blame the last person to touch the patient. But since the publication of To Err is Human, the call has been instead to use human factors and systems engineering methods and principles to solve patient safety problems. However, an understanding of the human factors and systems engineering is lacking, and confusion remains about what it means to apply their principles. This paper provides a primer on them and their applications to patient safety.

  10. Real time radiotherapy verification with Cherenkov imaging: development of a system for beamlet verification

    NASA Astrophysics Data System (ADS)

    Pogue, B. W.; Krishnaswamy, V.; Jermyn, M.; Bruza, P.; Miao, T.; Ware, William; Saunders, S. L.; Andreozzi, J. M.; Gladstone, D. J.; Jarvis, L. A.

    2017-05-01

    Cherenkov imaging has been shown to allow near real time imaging of the beam entrance and exit on patient tissue, with the appropriate intensified camera and associated image processing. A dedicated system has been developed for research into full torso imaging of whole breast irradiation, where the dual camera system captures the beam shape for all beamlets used in this treatment protocol. Particularly challenging verification measurement exists in dynamic wedge, field in field, and boost delivery, and the system was designed to capture these as they are delivered. Two intensified CMOS (ICMOS) cameras were developed and mounted in a breast treatment room, and pilot studies for intensity and stability were completed. Software tools to contour the treatment area have been developed and are being tested prior to initiation of the full trial. At present, it is possible to record delivery of individual beamlets as small as a single MLC thickness, and readout at 20 frames per second is achieved. Statistical analysis of system repeatibilty and stability is presented, as well as pilot human studies.

  11. Clinical quality standards for radiotherapy

    PubMed Central

    2012-01-01

    Aim of the study The technological progress that is currently being witnessed in the areas of diagnostic imaging, treatment planning systems and therapeutic equipment has caused radiotherapy to become a high-tech and interdisciplinary domain involving staff of various backgrounds. This allows steady improvement in therapy results, but at the same time makes the diagnostic, imaging and therapeutic processes more complex and complicated, requiring every stage of those processes to be planned, organized, controlled and improved so as to assure high quality of services provided. The aim of this paper is to present clinical quality standards for radiotherapy as developed by the author. Material and methods In order to develop the quality standards, a comparative analysis was performed between European and Polish legal acts adopted in the period of 1980-2006 and the universal industrial ISO 9001:2008 standard, defining requirements for quality management systems, and relevant articles published in 1984-2009 were reviewed, including applicable guidelines and recommendations of American, international, European and Polish bodies, such as the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy & Oncology (ESTRO), the International Atomic Energy Agency (IAEA), and the Organisation of European Cancer Institutes (OECI) on quality assurance and management in radiotherapy. Results As a result, 352 quality standards for radiotherapy were developed and categorized into the following three groups: 1 – organizational standards; 2 – physico-technical standards and 3 – clinical standards. Conclusion Proposed clinical quality standards for radiotherapy can be used by any institution using ionizing radiation for medical purposes. However, standards are of value only if they are implemented, reviewed, audited and improved, and if there is a clear mechanism in place to monitor and address failure to meet agreed standards. PMID:23788854

  12. Automatic detection system for multiple region of interest registration to account for posture changes in head and neck radiotherapy

    NASA Astrophysics Data System (ADS)

    Mencarelli, A.; van Beek, S.; Zijp, L. J.; Rasch, C.; van Herk, M.; Sonke, J.-J.

    2014-04-01

    Despite immobilization of head and neck (H and N) cancer patients, considerable posture changes occur over the course of radiotherapy (RT). To account for the posture changes, we previously implemented a multiple regions of interest (mROIs) registration system tailored to the H and N region for image-guided RT correction strategies. This paper is focused on the automatic segmentation of the ROIs in the H and N region. We developed a fast and robust automatic detection system suitable for an online image-guided application and quantified its performance. The system was developed to segment nine high contrast structures from the planning CT including cervical vertebrae, mandible, hyoid, manubrium of sternum, larynx and occipital bone. It generates nine 3D rectangular-shaped ROIs and informs the user in case of ambiguities. Two observers evaluated the robustness of the segmentation on 188 H and N cancer patients. Bland-Altman analysis was applied to a sub-group of 50 patients to compare the registration results using only the automatically generated ROIs and those manually set by two independent experts. Finally the time performance and workload were evaluated. Automatic detection of individual anatomical ROIs had a success rate of 97%/53% with/without user notifications respectively. Following the notifications, for 38% of the patients one or more structures were manually adjusted. The processing time was on average 5 s. The limits of agreement between the local registrations of manually and automatically set ROIs was comprised between ±1.4 mm, except for the manubrium of sternum (-1.71 mm and 1.67 mm), and were similar to the limits agreement between the two experts. The workload to place the nine ROIs was reduced from 141 s (±20 s) by the manual procedure to 59 s (±17 s) using the automatic method. An efficient detection system to segment multiple ROIs was developed for Cone-Beam CT image-guided applications in the H and N region and is clinically implemented in

  13. A dual cone-beam CT system for image guided radiotherapy: Initial performance characterization

    SciTech Connect

    Li Hao; Bowsher, James; Yin Fangfang; Giles, William

    2013-02-15

    Purpose: The purpose of this study is to evaluate the performance of a recently developed benchtop dual cone-beam computed tomography (CBCT) system with two orthogonally placed tube/detector sets. Methods: The benchtop dual CBCT system consists of two orthogonally placed 40 Multiplication-Sign 30 cm flat-panel detectors and two conventional x-ray tubes with two individual high-voltage generators sharing the same rotational axis. The x-ray source to detector distance is 150 cm and x-ray source to rotational axis distance is 100 cm for both subsystems. The objects are scanned through 200 Degree-Sign of rotation. The dual CBCT system utilized 110 Degree-Sign of projection data from one detector and 90 Degree-Sign from the other while the two individual single CBCTs utilized 200 Degree-Sign data from each detector. The system performance was characterized in terms of uniformity, contrast, spatial resolution, noise power spectrum, and CT number linearity. The uniformities, within the axial slice and along the longitudinal direction, and noise power spectrum were assessed by scanning a water bucket; the contrast and CT number linearity were measured using the Catphan phantom; and the spatial resolution was evaluated using a tungsten wire phantom. A skull phantom and a ham were also scanned to provide qualitative evaluation of high- and low-contrast resolution. Each measurement was compared between dual and single CBCT systems. Results: Compared to single CBCT, the dual CBCT presented: (1) a decrease in uniformity by 1.9% in axial view and 1.1% in the longitudinal view, as averaged for four energies (80, 100, 125, and 150 kVp); (2) comparable or slightly better contrast (0{approx}25 HU) for low-contrast objects and comparable contrast for high-contrast objects; (3) comparable spatial resolution; (4) comparable CT number linearity with R{sup 2}{>=} 0.99 for all four tested energies; (5) lower noise power spectrum in magnitude. Dual CBCT images of the skull phantom and the

  14. SU-E-J-29: Automatic Image Registration Performance of Three IGRT Systems for Prostate Radiotherapy

    SciTech Connect

    Barber, J; Sykes, J; Holloway, L; Thwaites, D

    2015-06-15

    Purpose: To compare the performance of an automatic image registration algorithm on image sets collected on three commercial image guidance systems, and explore its relationship with imaging parameters such as dose and sharpness. Methods: Images of a CIRS Virtually Human Male Pelvis phantom (VHMP) were collected on the CBCT systems of Varian TrueBeam/OBI and Elekta Synergy/XVI linear accelerators, across a range of mAs settings; and MVCT on a Tomotherapy Hi-ART accelerator with a range of pitch. Using the 6D correlation ratio algorithm of XVI, each image was registered to a mask of the prostate volume with a 5 mm expansion. Registrations were repeated 100 times, with random initial offsets introduced to simulate daily matching. Residual registration errors were calculated by correcting for the initial phantom set-up error. Automatic registration was also repeated after reconstructing images with different sharpness filters. Results: All three systems showed good registration performance, with residual translations <0.5mm (1σ) for typical clinical dose and reconstruction settings. Residual rotational error had larger range, with 0.8°, 1.2° and 1.9° for 1σ in XVI, OBI and Tomotherapy respectively. The registration accuracy of XVI images showed a strong dependence on imaging dose, particularly below 4mGy. No evidence of reduced performance was observed at the lowest dose settings for OBI and Tomotherapy, but these were above 4mGy. Registration failures (maximum target registration error > 3.6 mm on the surface of a 30mm sphere) occurred in 5% to 10% of registrations. Changing the sharpness of image reconstruction had no significant effect on registration performance. Conclusions: Using the present automatic image registration algorithm, all IGRT systems tested provided satisfactory registrations for clinical use, within a normal range of acquisition settings.

  15. Development of NIRS pencil beam scanning system for carbon ion radiotherapy

    NASA Astrophysics Data System (ADS)

    Furukawa, T.; Hara, Y.; Mizushima, K.; Saotome, N.; Tansho, R.; Saraya, Y.; Inaniwa, T.; Mori, S.; Iwata, Y.; Shirai, T.; Noda, K.

    2017-09-01

    At Heavy Ion Medical Accelerator in Chiba (HIMAC) in National Institute of Radiological Sciences (NIRS), more than 9000 patients have been successfully treated by carbon ion beams since 1994. The successful results of treatments have led us to construct a new treatment facility equipped with a three-dimensional pencil beam scanning irradiation system, which is one of sophisticated techniques for cancer therapy with high energetic ion beam. This new facility comprises two treatment rooms having fixed beam lines and one treatment room having rotating gantry line. The challenge of this project is to realize treatment of a moving target by scanning irradiation. Thus, to realize this, the development of the fast scanning system is one of the most important issues in this project. After intense commissioning and quality assurance tests, the treatment with scanned ion beam was started in May 2011. After treatment of static target starts, we have developed related technologies. As a result, we can start treatment of moving target and treatment without range shifter plates since 2015. In this paper, the developments of the scanning irradiation system are described.

  16. TU-G-201-03: Imaging Systems in Radiotherapy: Buying, Installing, and Using

    SciTech Connect

    Hunt, M.

    2015-06-15

    This session will update therapeutic physicists on technological advancements and radiation oncology features of commercial CT, MRI, and PET/CT imaging systems. Also described are physicists’ roles in every stage of equipment selection, purchasing, and operation, including defining specifications, evaluating vendors, making recommendations, and optimal and safe use of imaging equipment in radiation oncology environment. The first presentation defines important terminology of CT and PET/CT followed by a review of latest innovations, such as metal artifact reduction, statistical iterative reconstruction, radiation dose management, tissue classification by dual energy CT and spectral CT, improvement in spatial resolution and sensitivity in PET, and potentials of PET/MR. We will also discuss important technical specifications and items in CT and PET/CT purchasing quotes and their impacts. The second presentation will focus on key components in the request for proposal for a MRI simulator and how to evaluate vendor proposals. MRI safety issues in radiation Oncology, including MRI scanner Zones (4-zone design), will be discussed. Basic MR terminologies, important functionalities, and advanced features, which are relevant to radiation therapy, will be discussed. In the third presentation, justification of imaging systems for radiation oncology, considerations in room design and construction in a RO department, shared use with diagnostic radiology, staffing needs and training, clinical/research use cases and implementation, will be discussed. The emphasis will be on understanding and bridging the differences between diagnostic and radiation oncology installations, building consensus amongst stakeholders for purchase and use, and integrating imaging technologies into the radiation oncology environment. Learning Objectives: Learn the latest innovations of major imaging systems relevant to radiation therapy Be able to describe important technical specifications of CT, MRI

  17. Dosimetric effects of positioning shifts using 6D-frameless stereotactic Brainlab system in hypofractionated intracranial radiotherapy.

    PubMed

    Jin, Hosang; Keeling, Vance P; Ali, Imad; Ahmad, Salahuddin

    2016-01-01

    Dosimetric consequences of positional shifts were studied using frameless Brainlab ExacTrac X-ray system for hypofractionated (3 or 5 fractions) intracranial stereotactic radiotherapy (SRT). SRT treatments of 17 patients with metastatic intracranial tumors using the stereotactic system were retrospectively investigated. The treatments were simulated in a treatment planning system by modifying planning parameters with a matrix conversion technique based on positional shifts for initial infrared (IR)-based setup (XC: X-ray correction) and post-correction (XV: X-ray verification). The simulation was implemented with (a) 3D translational shifts only and (b) 6D translational and rotational shifts for dosimetric effects of angular correction. Mean translations and rotations (± 1 SD) of 77 fractions based on the initial IR setup (XC) were 0.51±0.86 mm (lateral), 0.30±1.55 mm (longitudinal), and -1.63±1.00 mm (vertical); 0.53±0.56 mm (pitch), 0.42±0.60 mm (roll), and 0.44±0.90 mm (yaw), respectively. These were -0.07±0.24 mm, -0.07±0.25 mm, 0.06±0.21 mm, 0.04±0.23 mm, 0.00±0.30 mm, and 0.02±0.22 mm, respectively, for the postcorrection (XV). Substantial degradation of the treatment plans was observed in D95 of PTV (2.6%±3.3%; simulated treatment versus treatment planning), Dmin of PTV (13.4%±11.6%), and Dmin of CTV (2.8%±3.8%, with the maximum error of 10.0%) from XC, while dosimetrically negligible changes (< 0.1%) were detected for both CTV and PTV from XV simulation. 3D angular correction significantly improved CTV dose coverage when the total angular shifts (|pitch|+|roll|+|yaw|) were greater than 2°. With the 6D stereoscopic X-ray verification imaging and frameless immobilization, submillimeter and subdegree accuracy is achieved with negligible dosimetric deviations. 3D angular correction is required when the angular deviation is substantial. A CTV-to-PTV safety margin of 2 mm is large enough to prevent deterioration of CTV

  18. Dosimetric effects of positioning shifts using 6D-frameless stereotactic Brainlab system in hypofractionated intracranial radiotherapy.

    PubMed

    Jin, Hosang; Keeling, Vance P; Ali, Imad; Ahmad, Salahuddin

    2016-01-08

    Dosimetric consequences of positional shifts were studied using frameless Brainlab ExacTrac X-ray system for hypofractionated (3 or 5 fractions) intracranial stereo-tactic radiotherapy (SRT). SRT treatments of 17 patients with metastatic intracranial tumors using the stereotactic system were retrospectively investigated. The treatments were simulated in a treatment planning system by modifying planning parameters with a matrix conversion technique based on positional shifts for initial infrared (IR)-based setup (XC: X-ray correction) and post-correction (XV: X-ray verification). The simulation was implemented with (a) 3D translational shifts only and (b) 6D translational and rotational shifts for dosimetric effects of angular correction. Mean translations and rotations (± 1 SD) of 77 fractions based on the initial IR setup (XC) were 0.51 ± 0.86 mm (lateral), 0.30 ± 1.55 mm (longitudinal), and -1.63 ± 1.00 mm (vertical); -0.53° ± 0.56° (pitch), 0.42° ± 0.60° (roll), and 0.44°± 0.90° (yaw), respectively. These were -0.07 ± 0.24 mm, -0.07 ± 0.25 mm, 0.06± 0.21 mm, 0.04° ± 0.23°, 0.00° ± 0.30°, and -0.02° ± 0.22°, respectively, for the postcorrection (XV). Substantial degradation of the treatment plans was observed in D95 of PTV (2.6% ± 3.3%; simulated treatment versus treatment planning), Dmin of PTV (13.4% ± 11.6%), and Dmin of CTV (2.8% ± 3.8%, with the maximum error of 10.0%) from XC, while dosimetrically negligible changes (< 0.1%) were detected for both CTV and PTV from XV simulation. 3D angular correction significantly improved CTV dose coverage when the total angular shifts (|pitch| + |roll| + |yaw|) were greater than 2°. With the 6D stereoscopic X-ray verification imaging and frameless immobilization, submillimeter and subdegree accuracy is achieved with negligible dosimetric deviations. 3D angular correction is required when the angular deviation is substantial. A CTV-to-PTV safety margin of 2 mm is large enough to prevent

  19. On-Board Imaging Validation of Optically Guided Stereotactic Radiosurgery Positioning System for Conventionally Fractionated Radiotherapy for Paranasal Sinus and Skull Base Cancer

    SciTech Connect

    Maxim, Peter G.; Loo, Billy W.; Murphy, James D.; Chu, Karen P.M.; Hsu, Annie; Le, Quynh-Thu

    2011-11-15

    Purpose: To evaluate the positioning accuracy of an optical positioning system for stereotactic radiosurgery in a pilot experience of optically guided, conventionally fractionated, radiotherapy for paranasal sinus and skull base tumors. Methods and Materials: Before each daily radiotherapy session, the positioning of 28 patients was set up using an optical positioning system. After this initial setup, the patients underwent standard on-board imaging that included daily orthogonal kilovoltage images and weekly cone beam computed tomography scans. Daily translational shifts were made after comparing the on-board images with the treatment planning computed tomography scans. These daily translational shifts represented the daily positional error in the optical tracking system and were recorded during the treatment course. For 13 patients treated with smaller fields, a three-degree of freedom (3DOF) head positioner was used for more accurate setup. Results: The mean positional error for the optically guided system in patients with and without the 3DOF head positioner was 1.4 {+-} 1.1 mm and 3.9 {+-} 1.6 mm, respectively (p <.0001). The mean positional error drifted 0.11 mm/wk upward during the treatment course for patients using the 3DOF head positioner (p = .057). No positional drift was observed in the patients without the 3DOF head positioner. Conclusion: Our initial clinical experience with optically guided head-and-neck fractionated radiotherapy was promising and demonstrated clinical feasibility. The optically guided setup was especially useful when used in conjunction with the 3DOF head positioner and when it was recalibrated to the shifts using the weekly portal images.

  20. Technical Note: The design and function of a horizontal patient rotation system for the purposes of fixed-beam cancer radiotherapy.

    PubMed

    Feain, Ilana; Coleman, Lloyd; Wallis, Hue; Sokolov, Richard; O'Brien, Ricky; Keall, Paul

    2017-06-01

    Cancer radiation therapy treatment is performed by delivering a 3D dose distribution to the tumor via the relative rotation between beam and patient. While most modern machines rotate the radiation beam around a still patient, the treatment can also be delivered by rotating the patient relative to a fixed beam. Fixed-beam, patient rotation radiotherapy machines show promise for reducing the size, surface area footprint, and shielding requirements compared with rotating gantry machines. In this Technical Note, we describe the development of a bespoke horizontal patient rotation system for the purposes of a fixed-beam cancer radiotherapy architecture. A horizontal Patient Rotation System was designed in accordance with the appropriate standards pertaining to performance and safety of medical electrical equipment and medical linear accelerators (ISO 9001, IEC 60601-1, IEC 60601-2-1, ISO 14971, ISO 13485, 21CFR820, IEC 62304, Machinery Directive 98/37/EC). The principal criteria for the design were safety, patient comfort, real-time control and the ability to be integrated with other radiation therapy componentry (including a linear accelerator and kV imaging systems). A first of its kind device for securing, immobilizing, translating, and rotating patients has been designed and built and tested against 161 different design, safety, and usability specifications. The device has real-time control for all critical applications. We designed and built a bespoke device which can translate and rotate patients 360° around a horizontal axis. The device meets all design and safety criteria with early usability tests indicating a high degree of comfort and utility. The system has been installed in a clinical bunker, integrated with a fixed-beam linear accelerator and is currently being commissioned for the purposes of cancer radiotherapy treatment. © 2017 American Association of Physicists in Medicine.

  1. An online x-ray based position validation system for prostate hypofractionated radiotherapy

    SciTech Connect

    Arumugam, Sankar Xing, Aitang; Sidhom, Mark; Holloway, Lois

    2016-02-15

    Purpose: Accurate positioning of the target volume during treatment is paramount for stereotactic body radiation therapy (SBRT). In this work, the authors present the development of an in-house software tool to verify target position with an Elekta-Synergy linear accelerator using kV planar images acquired during treatment delivery. Methods: In-house software, SeedTracker, was developed in MATLAB to perform the following three functions: 1. predict intended seed positions in a planar view perpendicular to any gantry angle, simulating a portal imaging device, from the 3D seed co-ordinates derived from the treatment planning system; 2. autosegment seed positions in kV planar images; and 3. report the position shift based on the seed positions in the projection images. The performance of SeedTracker was verified using a CIRS humanoid phantom (CIRS, VA, USA) implanted with three Civco gold seed markers (Civco, IA, USA) in the prostate. The true positive rate of autosegmentation (TPR{sub seg}) and the accuracy of the software in alerting the user when the isocenter position was outside the tolerance (TPR{sub trig}) were studied. Two-dimensional and 3D static position offsets introduced to the humanoid phantom and 3D dynamic offsets introduced to a gel phantom containing gold seeds were used for evaluation of the system. Results: SeedTracker showed a TPR{sub seg} of 100% in the humanoid phantom for projection images acquired at all angles except in the ranges of 80°–100° and 260°–280° where seeds are obscured by anatomy. This resulted in a TPR{sub trig} of 88% over the entire treatment range for considered 3D static offsets introduced to the phantom. For 2D static offsets where the position offsets were only introduced in the anterior–posterior and lateral directions, the TPR{sub trig} of SeedTracker was limited by both seed detectability and positional offset. SeedTracker showed a false positive trigger in the projection angle range between 130°–170° and

  2. Thermoresponsive polymer system based on poly(N-vinylcaprolactam) intended for local radiotherapy applications.

    PubMed

    Černoch, Peter; Černochová, Zulfiya; Kučka, Jan; Hrubý, Martin; Petrova, Svetlana; Štěpánek, Petr

    2015-04-01

    Brachytherapy represents effective local therapy of unresectable solid tumors with very few side effects. Radiolabeled thermoresponsive polymers offer almost noninvasive approach to brachytherapy applications. A radioiodinated, water-soluble, thermosensitive poly(N-vinylcaprolactam) (PVCL) polymer was prepared using two approaches. The direct copolymerization with N-methacryloyl-l-tyrosinamide, as well as end-capping of carboxy-terminated PVCL homopolymer with tyramine, were used. In both cases the product was successfully radiolabeled with (125)I. The obtained polymers demonstrate cloud-point temperature (TC) values in the range of 33-35°C in all the studied solvent systems (water, PBS (pH 7.4) and physiological saline solution). Above the cloud point temperature, the molecularly dissolved polymer is macroprecipitated from the solution. The TC values close to the human body temperature of this biocompatible poly(N-vinylcaprolactam) polymer makes it a promising material intended for local therapy of solid tumors.

  3. Quality Assurance of Immobilization and Target Localization Systems for Frameless Stereotactic Cranial and Extracranial Hypofractionated Radiotherapy

    SciTech Connect

    Solberg, Timothy D. Medin, Paul M.; Mullins, John; Li Sicong

    2008-05-01

    The success of stereotactic radiosurgery has stimulated significant interest in the application of such an approach for the treatment of extracranial tumors. The potential benefits of reduced healthcare costs and improved patient outcomes that could be realized in a high-precision, hypofractionated treatment paradigm are numerous. Image-guidance technologies are eliminating the historic requirement for rigid head fixation and will also accelerate the clinical implementation of the approach in extracranial sites. An essential prerequisite of 'frameless' stereotactic systems is that they provide localization accuracy consistent with the safe delivery of a therapeutic radiation dose given in one or few fractions. In this report, we reviewed the technologies for frameless localization of cranial and extracranial targets with emphasis on the quality assurance aspects.

  4. The use of photostimulable phosphor systems for periodic quality assurance in radiotherapy.

    PubMed

    Conte, L; Bianchi, C; Cassani, E; Monciardini, M; Mordacchini, C; Novario, R; Strocchi, S; Stucchi, P; Tanzi, F

    2008-03-01

    The fusion of radiological and optical images can be achieved through charging a photostimulable phosphor plate (PSP) with an exposure to a field of X- or gamma-rays, followed by exposure to an optical image which discharges the plate in relation to the amount of incident light. According to this PSP characteristic, we developed a simple method for periodic quality assurance (QA) of light/radiation field coincidence, distance indicator, field size indicators, crosshair centering, coincidence of radiation and mechanical isocenter for linear accelerators. The geometrical accuracy of radiological units can be subjected to the same QA method. Further, the source position accuracy for an HDR remote afterloader can be checked by taking an autoradiography of the radioactive source and simultaneously an optical image of a reference geometrical system.

  5. Commissioning of a novel microCT/RT system for small animal conformal radiotherapy

    PubMed Central

    Rodriguez, Manuel; Zhou, Hu; Keall, Paul; Graves, Edward

    2010-01-01

    The purpose of this work was to commission a 120 kVp photon beam produced by a micro-computed tomography (microCT) scanner for use in irradiating mice to therapeutic doses. A variable-aperture collimator has been integrated with a microCT scanner to allow the delivery of beams with pseudocircular profiles of arbitrary width between 0.1 and 6.0 cm. The dose rate at the isocenter of the system was measured using ion chamber and gafchromic EBT film as 1.56–2.13 Gy min−1 at the water surface for field diameters between 0.2 and 6.0 cm. The dose rate decreases approximately 10% per every 5 mm depth in water for field diameters between 0.5 and 1.0 cm. The flatness, symmetry and penumbra of the beam are 3.6%, 1.0% and 0.5 mm, respectively. These parameters are sufficient to accurately conform the radiation dose delivered to target organs on mice. The irradiated field size is affected principally by the divergence of the beam. In general, the beam has appropriate dosimetric characteristics to accurately deliver the dose to organs inside the mice’s bodies. Using multiple beams delivered from a variety of angular directions, targets as small as 2 mm may be irradiated while sparing surrounding tissue. This microCT/RT system is a feasible tool to irradiate mice using treatment planning and delivery methods analogous to those applied to humans. PMID:19478377

  6. Reformulation of a clinical-dose system for carbon-ion radiotherapy treatment planning at the National Institute of Radiological Sciences, Japan

    NASA Astrophysics Data System (ADS)

    Inaniwa, Taku; Kanematsu, Nobuyuki; Matsufuji, Naruhiro; Kanai, Tatsuaki; Shirai, Toshiyuki; Noda, Koji; Tsuji, Hiroshi; Kamada, Tadashi; Tsujii, Hirohiko

    2015-04-01

    At the National Institute of Radiological Sciences (NIRS), more than 8,000 patients have been treated for various tumors with carbon-ion (C-ion) radiotherapy in the past 20 years based on a radiobiologically defined clinical-dose system. Through clinical experience, including extensive dose escalation studies, optimum dose-fractionation protocols have been established for respective tumors, which may be considered as the standards in C-ion radiotherapy. Although the therapeutic appropriateness of the clinical-dose system has been widely demonstrated by clinical results, the system incorporates several oversimplifications such as dose-independent relative biological effectiveness (RBE), empirical nuclear fragmentation model, and use of dose-averaged linear energy transfer to represent the spectrum of particles. We took the opportunity to update the clinical-dose system at the time we started clinical treatment with pencil beam scanning, a new beam delivery method, in 2011. The requirements for the updated system were to correct the oversimplifications made in the original system, while harmonizing with the original system to maintain the established dose-fractionation protocols. In the updated system, the radiation quality of the therapeutic C-ion beam was derived with Monte Carlo simulations, and its biological effectiveness was predicted with a theoretical model. We selected the most used C-ion beam with αr = 0.764 Gy-1 and β = 0.0615 Gy-2 as reference radiation for RBE. The C-equivalent biological dose distribution is designed to allow the prescribed survival of tumor cells of the human salivary gland (HSG) in entire spread-out Bragg peak (SOBP) region, with consideration to the dose dependence of the RBE. This C-equivalent biological dose distribution is scaled to a clinical dose distribution to harmonize with our clinical experiences with C-ion radiotherapy. Treatment plans were made with the original and the updated clinical-dose systems, and both

  7. Evaluation of the Accuracy of a 3D Surface Imaging System for Patient Setup in Head and Neck Cancer Radiotherapy

    SciTech Connect

    Gopan, Olga; Wu Qiuwen

    2012-10-01

    Purpose: To evaluate the accuracy of three-dimensional (3D) surface imaging system (AlignRT) registration algorithms for head-and-neck cancer patient setup during radiotherapy. Methods and Materials: Eleven patients, each undergoing six repeated weekly helical computed tomography (CT) scans during treatment course (total 77 CTs including planning CT), were included in the study. Patient surface images used in AlignRT registration were not captured by the 3D cameras; instead, they were derived from skin contours from these CTs, thereby eliminating issues with immobilization masks. The results from surface registrations in AlignRT based on CT skin contours were compared to those based on bony anatomy registrations in Pinnacle{sup 3}, which was considered the gold standard. Both rigid and nonrigid types of setup errors were analyzed, and the effect of tumor shrinkage was investigated. Results: The maximum registration errors in AlignRT were 0.2 Degree-Sign for rotations and 0.7 mm for translations in all directions. The rigid alignment accuracy in the head region when applied to actual patient data was 1.1 Degree-Sign , 0.8 Degree-Sign , and 2.2 Degree-Sign in rotation and 4.5, 2.7, and 2.4 mm in translation along the vertical, longitudinal, and lateral axes at 90% confidence level. The accuracy was affected by the patient's weight loss during treatment course, which was patient specific. Selectively choosing surface regions improved registration accuracy. The discrepancy for nonrigid registration was much larger at 1.9 Degree-Sign , 2.4 Degree-Sign , and 4.5 Degree-Sign and 10.1, 11.9, and 6.9 mm at 90% confidence level. Conclusions: The 3D surface imaging system is capable of detecting rigid setup errors with good accuracy for head-and-neck cancer. Further investigations are needed to improve the accuracy in detecting nonrigid setup errors.

  8. Validation of biomechanical deformable image registration in the abdomen, thorax, and pelvis in a commercial radiotherapy treatment planning system.

    PubMed

    Velec, Michael; Moseley, Joanne L; Svensson, Stina; Hårdemark, Björn; Jaffray, David A; Brock, Kristy K

    2017-07-01

    The accuracy of deformable image registration tools can vary widely between imaging modalities and specific implementations of the same algorithms. A biomechanical model-based algorithm initially developed in-house at an academic institution was translated into a commercial radiotherapy treatment planning system and validated for multiple imaging modalities and anatomic sites. Biomechanical deformable registration (Morfeus) is a geometry-driven algorithm based on the finite element method. Boundary conditions are derived from the model-based segmentation of controlling structures in each image which establishes a point-to-point surface correspondence. For each controlling structure, material properties and fixed or sliding interfaces are assigned. The displacements of internal volumes for controlling structures and other structures implicitly deformed are solved with finite element analysis. Registration was performed for 74 patients with images (mean vector resolution) of thoracic and abdominal 4DCT (2.8 mm) and MR (5.3 mm), liver CT-MR (4.5 mm), and prostate MR (2.6 mm). Accuracy was quantified between deformed and actual target images using distance-to-agreement (DTA) for structure surfaces and the target registration error (TRE) for internal point landmarks. The results of the commercial implementation were as follows. The mean DTA was ≤ 1.0 mm for controlling structures and 1.0-3.5 mm for implicitly deformed structures on average. TRE ranged from 2.0 mm on prostate MR to 5.1 mm on lung MR on average, within 0.1 mm or lower than the image voxel sizes. Accuracy was not overly sensitive to changes in the material properties or variability in structure segmentations, as changing these inputs affected DTA and TRE by ≤ 0.8 mm. Maximum DTA > 5 mm occurred for 88% of the structures evaluated although these were within the inherent segmentation uncertainty for 82% of structures. Differences in accuracy between the commercial and in-house research

  9. Development of a new ridge filter with honeycomb geometry for a pencil beam scanning system in particle radiotherapy

    NASA Astrophysics Data System (ADS)

    Tansho, R.; Furukawa, T.; Hara, Y.; Mizushima, K.; Saotome, N.; Saraya, Y.; Shirai, T.; Noda, K.

    2017-09-01

    A ridge filter (RGF), a beam energy modulation device, is usually used for particle radiotherapy with a pencil beam scanning system. The conventional RGF has a one-dimensional (1D) periodic laterally stepped structure in orthogonal plane with a central beam direction. The energy of a beam passing through the different thicknesses of the stepped RGF is modulated. Although the lateral pencil beam size is required to cover the several stepped RGF units to modulate its energy as designed, the current trend is to decrease lateral beam size to improve the scanning system. As a result, the beam size becomes smaller than the size of the individual RGF unit. The aim of this study was to develop a new RGF with two-dimensional (2D) honeycomb geometry to simultaneously achieve both a decrease in lateral beam size and the desired energy modulation. The conventional 1D-RGF and the 2D-RGF with honeycomb geometry were both designed so that the Bragg peak size of a 79 MeV/u carbon ion pencil beam in water was 1 mm RMS in the beam direction. To validate the design of the 2D-RGF, we calculated depth dose distributions in water using a simplified Monte Carlo method. In the calculations, we decreased the lateral pencil beam size at the entrance of the RGF and investigated the threshold of lateral beam size with which the pencil beam can reproduce the desired Bragg peak size for each type of RGF. In addition, we calculated lateral dose distributions in air downstream from the RGF and evaluated the inhomogeneity of the lateral dose distributions. Using the 2D-RGF, the threshold of lateral beam size with which the pencil beam can reproduce the desired Bragg peak size was smaller than that using the 1D-RGF. Moreover, the distance from the RGF at which the lateral dose distribution becomes uniform was shorter using the 2D-RGF than that using the 1D-RGF. These results indicate that when the periodic length of both RGFs is the same, the 2D-RGF allows use of a pencil beam with smaller lateral

  10. FMEA of manual and automated methods for commissioning a radiotherapy treatment planning system.

    PubMed

    Wexler, Amy; Gu, Bruce; Goddu, Sreekrishna; Mutic, Maya; Yaddanapudi, Sridhar; Olsen, Lindsey; Harry, Taylor; Noel, Camille; Pawlicki, Todd; Mutic, Sasa; Cai, Bin

    2017-09-01

    To evaluate the level of risk involved in treatment planning system (TPS) commissioning using a manual test procedure, and to compare the associated process-based risk to that of an automated commissioning process (ACP) by performing an in-depth failure modes and effects analysis (FMEA). The authors collaborated to determine the potential failure modes of the TPS commissioning process using (a) approaches involving manual data measurement, modeling, and validation tests and (b) an automated process utilizing application programming interface (API) scripting, preloaded, and premodeled standard radiation beam data, digital heterogeneous phantom, and an automated commissioning test suite (ACTS). The severity (S), occurrence (O), and detectability (D) were scored for each failure mode and the risk priority numbers (RPN) were derived based on TG-100 scale. Failure modes were then analyzed and ranked based on RPN. The total number of failure modes, RPN scores and the top 10 failure modes with highest risk were described and cross-compared between the two approaches. RPN reduction analysis is also presented and used as another quantifiable metric to evaluate the proposed approach. The FMEA of a MTP resulted in 47 failure modes with an RPNave of 161 and Save of 6.7. The highest risk process of "Measurement Equipment Selection" resulted in an RPNmax of 640. The FMEA of an ACP resulted in 36 failure modes with an RPNave of 73 and Save of 6.7. The highest risk process of "EPID Calibration" resulted in an RPNmax of 576. An FMEA of treatment planning commissioning tests using automation and standardization via API scripting, preloaded, and pre-modeled standard beam data, and digital phantoms suggests that errors and risks may be reduced through the use of an ACP. © 2017 American Association of Physicists in Medicine.

  11. Systemic Tolerance Mediated by Melanoma Brain Tumors is Reversible by Radiotherapy and Vaccination

    PubMed Central

    Jackson, Christopher M.; Kochel, Christina M.; Nirschl, Christopher J.; Durham, Nicholas M.; Ruzevick, Jacob; Alme, Angela; Francica, Brian J.; Elias, Jimmy; Daniels, Andrew; Dubensky, Thomas W.; Lauer, Peter; Brockstedt, Dirk G.; Baxi, Emily G.; Calabresi, Peter A.; Taube, Janis M.; Pardo, Carlos A.; Brem, Henry; Pardoll, Drew M.; Lim, Michael; Drake, Charles G.

    2016-01-01

    Purpose Immune responses to antigens originating in the CNS are generally attenuated, since collateral damage can have devastating consequences. The significance of this finding for the efficacy of tumor-targeted immunotherapies is largely unknown. Experimental Design The B16 murine melanoma model was used to compare cytotoxic responses against established tumors in the CNS and in the periphery. Cytokine analysis of tissues from brain tumor-bearing mice detected elevated TGF-β secretion from microglia and in the serum and TGF-β signaling blockade reversed tolerance of tumor antigen-directed CD8 T cells. Additionally, a treatment regimen using focal radiation therapy and recombinant Listeria monocytogenes was evaluated for immunologic activity and efficacy in this model. Results CNS melanomas were more tolerogenic than equivalently progressed tumors outside the CNS as antigen-specific CD8 T cells were deleted and exhibited impaired cytotoxicity. Tumor-bearing mice had elevated serum levels of TGF-β; however, blocking TGF-β signaling with a small molecule inhibitor or a monoclonal antibody did not improve survival. Conversely, tumor antigen-specific vaccination in combination with focal radiation therapy reversed tolerance and improved survival. This treatment regimen was associated with increased polyfunctionality of CD8 T cells, elevated T effector to T regulatory cell ratios and decreased TGF-β secretion from microglia. Conclusions These data suggest that CNS tumors may impair systemic antitumor immunity and consequently accelerate cancer progression locally as well as outside the CNS while antitumor immunity may be restored by combining vaccination with radiation therapy. These findings are hypothesis-generating and warrant further study in more contemporary melanoma models as well as human trials. PMID:26490306

  12. Treatment planning system and dose delivery accuracy in extracranial stereotactic radiotherapy using Elekta body frame

    NASA Astrophysics Data System (ADS)

    Dawod, Tamer; Bremer, Michael; Karstens, Johann H.; Werner, Martin

    2010-01-01

    The purpose of this study was to measure the photon beam transmission through the Elekta Stereotactic Body Frame (ESBF) and treatment couch, to determine the dose calculations accuracy of the MasterPlan Treatment Planning System (TPS) using Pencil Beam (PBA) and Collapsed Cone (CCA) algorithms during the use of Elekta Stereotactic Body Frame (ESBF), and to demonstrate a simple calculation method to put this transmission into account during the treatment planning dose calculations. The dose was measured at the center of an in-house custom-built inhomogeneous PMMA thorax phantom with and without ‘the frame + treatment couch’. The phantom was CT-imaged inside the ESBF and planned with multiple 3D-CRT fields using PBA and CCA for photon beams of energies 6 MV and 10 MV. There were two treatment plans for dose calculations. In the first plan, the ‘frame + couch’ were included in the body contour and, therefore, included in the TPS dose calculations. In the second plan, the ‘frame + couch’ were not included in the body contour and, therefore, not included in the calculations. Transmission of the ‘frame + couch’ was determined by the ratio of the dose measurements with the ‘frame + couch’ to the measurements without them. To validate the accuracy of the calculation model, plans with and without the ‘frame + couch’ surrounding the phantoms were compared with their corresponding measurements. The transmission of the ‘frame + couch’ varies from 90.23-97.54% depending on the energy, field size, the angle of the beams and whether the beams also intercept them. The validation accuracy of the Pencil Beam (PBA) and Collapsed Cone (CCA) algorithms were within 5.33% and 4.04% respectively for the individual measurements for all gantry angles under this study. The results showed that both PBA and CCA algorithms can calculate the dose to the target within 4.25% and 1.95% of the average measured value. The attenuation caused by the ESBF and couch must be

  13. WE-F-16A-06: Using 3D Printers to Create Complex Phantoms for Dose Verification, Quality Assurance, and Treatment Planning System Commissioning in Radiotherapy

    SciTech Connect

    Kassaee, A; Ding, X; McDonough, J; Reiche, M; Witztum, A; Teo, B

    2014-06-15

    Purpose: To use 3D printers to design and construct complex geometrical phantoms for commissioning treatment planning systems, dose calculation algorithms, quality assurance (QA), dose delivery, and patient dose verifications. Methods: In radiotherapy, complex geometrical phantoms are often required for dose verification, dose delivery and calculation algorithm validation. Presently, fabrication of customized phantoms is limited due to time, expense and challenges in machining of complex shapes. In this work, we designed and utilized 3D printers to fabricate two phantoms for QA purposes. One phantom includes hills and valleys (HV) for verification of intensity modulated radiotherapy for photons, and protons (IMRT and IMPT). The other phantom includes cylindrical cavities (CC) of various sizes for dose verification of inhomogeneities. We evaluated the HV phantoms for an IMPT beam, and the CC phantom to study various inhomogeneity configurations using photon, electron, and proton beams. Gafcromic ™ films were used to quantify the dose distributions delivered to the phantoms. Results: The HV phantom has dimensions of 12 cm × 12 cm and consists of one row and one column of five peaks with heights ranging from 2 to 5 cm. The CC phantom has a size 10 cm × 14 cm and includes 6 cylindrical cavities with length of 7.2 cm and diameters ranging from 0.6 to 1.2 cm. The IMPT evaluation using the HV phantom shows good agreement as compared to the dose distribution calculated with treatment planning system. The CC phantom also shows reasonable agreements for using different algorithms for each beam modalities. Conclusion: 3D printers with submillimiter resolutions are capable of printing complex phantoms for dose verification and QA in radiotherapy. As printing costs decrease and the technology becomes widely available, phantom design and construction will be readily available to any clinic for testing geometries that were not previously feasible.

  14. Long-Term Follow-Up of Dose-Adapted and Reduced-Field Radiotherapy With or Without Chemotherapy for Central Nervous System Germinoma

    SciTech Connect

    Jensen, Ashley W.; Issa Laack, Nadia N.; Buckner, Jan C.; Schomberg, Paula J.; Wetmore, Cynthia J.; Brown, Paul D.

    2010-08-01

    Purpose: To update our institutional experience with neoadjuvant chemotherapy and minimized radiotherapy vs. radiation monotherapy for intracranial germinoma. Methods and Materials: We retrospectively reviewed records of 59 patients with diagnosis of primary intracranial germinoma between 1977 and 2007. Treatment was irradiation alone or neoadjuvant platinum-based chemotherapy and local irradiation (initial tumor plus margin) for patients with localized complete response and reduced-dose craniospinal irradiation for others. Results: For the chemoradiotherapy group (n = 28), median follow-up was 7 years. No patient died. The freedom from progression (FFP) rate was 88% at 5 years and 80% at 10 years. In 4 patients, disease recurred 1.1 to 6.8 years after diagnosis. All were young male patients who received 30.6 Gy to local fields after complete response to chemotherapy. The FFP rate was 88% for local irradiation vs. 100% for more extensive fields (p = .06). For the radiotherapy-alone group (n = 31), median follow-up was 15 years. Overall and disease-free survival rates were 93% and 93% at 5 years and 90% and 87% at 15 years. In 5 patients, disease recurred 1.1 to 4.9 years after diagnosis. Most patients in this group were young men 18 to 23 years of age with suprasellar primary disease treated with about 50 Gy to local fields. The FFP rate was 44% for local irradiation vs. 100% for more extensive fields (p < .01). Conclusions: The addition of neoadjuvant chemotherapy to local-field radiotherapy reduced central nervous system cancer recurrence when high-risk patients were excluded by thorough pretreatment staging. There was trend toward improved central nervous system tumor control when larger fields (whole brain, whole ventricle, or craniospinal axis) were used.

  15. SU-E-T-130: Dosimetric Evaluation of Tissue Equivalent Gel Dosimeter Using Saccharide in Radiotherapy System

    SciTech Connect

    Cho, Y; Lee, D; Jung, H; Ji, Y; Kim, K; Chang, U; Kwon, S

    2014-06-01

    Purpose: In this study, the dose responses of the MAGIC gel with various concentrations and type of saccharide are examined to clarify the roles of mono and disaccharide in the polymerization process. Then we focused on the tissue equivalence and dose sensitivity of MAGIC gel dosimeters. Methods: The gel is composed of HPLC, 8% gelatin, 2 × 10-3 M L-ascorbic acid, 1.8 × 10-2 M hydroquinone, 8 × 10-5 M copper(II)sulfate and 9% methacrylic acid, new polymer gels are synthesized by adding glucose(monosaccharide), sucrose(disaccharide) and urea in the concentration range of 5∼35%. For irradiation of the gel, cesium-137 gamma-ray irradiator was used, radiation dose was delivered from 5∼50 Gy. MRI images of the gel were acquired by using a 3.0 T MRI system. Results: When saccharide and urea were added, the O/C, O/N and C/N ratios agreed with those of soft tissue with 1.7%. The dose-response of glucose and sucrose gel have slope-to-intercept ratio of 0.044 and 0.283 respectively. The slope-to-ratio is one important determinant of gel sensitivity. R-square values of glucose and sucrose gel dosimeters were 0.984 and 0.994 respectively. Moreover when urea were added, the slope-to-intercept ratio is 0.044 and 0.073 respectively. R-square values of mono and disaccharide gel were 0.973 and 0.989 respectively. When a saccharide is added into the MAGIC gel dosimeter, dose sensitivity is increased. However when urea were added, dose sensitivity is slightly decreased. Conclusion: In this study, it was possible to obtain the following conclusions by looking at the dose response characteristics after adding mono-, di-saccharide and urea to a MAGIC gel dosimeter. Saccharide was a tendency of increasing dose sensitivity with disaccharide. Sa.ccharide is cost effective, safe, soft tissue equivalent, and can be used under various experimental conditions, making it a suitable dosimeter for some radiotherapy applications.

  16. [Radiotherapy of hypopharynx cancers].

    PubMed

    Pointreau, Y; Lafond, C; Trémolières, P; Legouté, F; Servagi-Vernat, S; Giraud, P; Maingon, P; Calais, G; Lapeyre, M

    2016-09-01

    The intensity-modulated radiotherapy is the gold standard in the treatment of hypopharynx cancers. Early T1 and T2 tumours could be treated by exclusive radiotherapy or surgery. For tumours requiring total pharyngolaryngectomy (T2 or T3), induction chemotherapy followed by exclusive radiotherapy or concurrent chemoradiotherapy are possible. For T4 tumours, surgery must be proposed. The treatment of lymph nodes is based on the initial treatment of the primary tumour. In non-surgical procedure, in case of sequential radiotherapy, curative dose is 70Gy and prophylactic dose is 50Gy. An integrated simultaneous boost radiotherapy is allowed (70Gy in 2Gy per fraction and 56Gy in 1.8Gy per fraction or 70Gy in 2.12Gy per fraction). Postoperatively, radiotherapy is used for locally advanced cancers with dose levels based on pathologic criteria (66Gy for R1 resection, 50 to 54Gy for complete resection). Volume delineation is based on guidelines.

  17. Heavy-ion radiotherapy

    NASA Astrophysics Data System (ADS)

    Kanai, Tatsuaki

    2000-11-01

    Heavy-ion radiotherapy using high-energy carbon beams has been performed at the National Institute of Radiological Sciences, Japan. The physical frame works for heavy-ion radiotherapy are established using physical understandings of radiation physics. In order to increase the accuracy of heavy-ion radiotherapy, many physical problems should be solved. Unsolved problems, such as the depth dose distributions, range of heavy-ion in patients and heavy-ion dosimetry in the radiation therapy, are discussed. .

  18. A noninvasive eye fixation and computer-aided eye monitoring system for linear accelerator-based stereotactic radiotherapy of uveal melanoma.

    PubMed

    Bogner, Joachim; Petersch, Bernhard; Georg, Dietmar; Dieckmann, Karin; Zehetmayer, Martin; Pötter, Richard

    2003-07-15

    To introduce a noninvasive eye fixation and computer-aided eye monitoring system for linear accelerator-based stereotactic radiotherapy for uveal melanoma. At the Department of Radiotherapy and Radiobiology, University of Vienna, stereotactic radiotherapy is offered to patients with uveal melanoma considered unsuitable for (106)Ru brachytherapy or local resection. For the present feasibility study, 8 patients were carefully selected according to their ability to fixate a small light source with the diseased eye and whether they had a rather small head to meet the limited geometric space available. A polymethyl methacrylate tube was attached to a stereotactic mask system in craniocaudal orientation supporting a 45 degrees mirror, which was placed in front of the diseased eye. At the other end of the tube, the patient was given a small fixation light, and a small camera was positioned beneath, which was shielded for use during MRI. A computer interface calculated and visualized the spatial difference of the actual and a given reference pupil position, which was defined before CT scanning, during the MRI sequences, and during treatment delivery at the linear accelerator. The described system can be attached to a conventional stereotactic mask system with minor modifications. Because of the large distance between the eye and the fixation light, the optical fixation system was well tolerated by all patients, and a stable position of the eye was obtained. The camera system can be used during CT and MRI without interference. Absorption of the 6-MV photon beam by the mirror and the polymethyl methacrylate tube was negligible. The computer interface designed to determine the pupil position uses an image-processing algorithm that correlates a template of the reference image with the actual image of the eye. Provided sufficient illumination of the pupil, the correlation function showed a pronounced minimum at the reference position. The precision of the algorithm was tested

  19. [Radiotherapy of oropharynx carcinoma].

    PubMed

    Servagi Vernat, S; Tochet, F; Vieillevigne, L; Pointreau, Y; Maingon, P; Giraud, P

    2016-09-01

    Indication, doses, technique of radiotherapy and concomitant chemotherapy for oropharynx carcinoma are presented. The recommendations for delineation of the target volumes and organs at risk are detailed.

  20. Patient safety in external beam radiotherapy, results of the ACCIRAD project: Current status of proactive risk assessment, reactive analysis of events, and reporting and learning systems in Europe.

    PubMed

    Malicki, Julian; Bly, Ritva; Bulot, Mireille; Godet, Jean-Luc; Jahnen, Andreas; Krengli, Marco; Maingon, Philippe; Prieto Martin, Carlos; Przybylska, Kamila; Skrobała, Agnieszka; Valero, Marc; Jarvinen, Hannu

    2017-04-01

    To describe the current status of implementation of European directives for risk management in radiotherapy and to assess variability in risk management in the following areas: 1) in-country regulatory framework; 2) proactive risk assessment; (3) reactive analysis of events; and (4) reporting and learning systems. The original data were collected as part of the ACCIRAD project through two online surveys. Risk assessment criteria are closely associated with quality assurance programs. Only 9/32 responding countries (28%) with national regulations reported clear "requirements" for proactive risk assessment and/or reactive risk analysis, with wide variability in assessment methods. Reporting of adverse error events is mandatory in most (70%) but not all surveyed countries. Most European countries have taken steps to implement European directives designed to reduce the probability and magnitude of accidents in radiotherapy. Variability between countries is substantial in terms of legal frameworks, tools used to conduct proactive risk assessment and reactive analysis of events, and in the reporting and learning systems utilized. These findings underscore the need for greater harmonisation in common terminology, classification and reporting practices across Europe to improve patient safety and to enable more reliable inter-country comparisons. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. The kallikrein-kinin-system in head and neck squamous cell carcinoma (HNSCC) and its role in tumour survival, invasion, migration and response to radiotherapy.

    PubMed

    Beck, Carolin; Piontek, Guido; Haug, Anna; Bas, Murat; Knopf, Andreas; Stark, Thomas; Mißlbeck, Martin; Rudelius, Martina; Reiter, Rudolf; Brandstetter, Markus; Pickhard, Anja

    2012-12-01

    In this study, we investigated the role of the kallikrein-kinin-system in head and neck squamous cell carcinoma (HNSCC) and its implication on tumour survival, invasion, migration and response to radiotherapy. The expression of BKB2R was studied in a series of 180 tumour samples to determine the functional significance of BKB2R in HNSCC. Additionally, four different HNSCC cell lines were treated with an irradiation dose of 8Gy following bradykinin receptor stimulation or blockage. Tumour cell survival was tested using a colony formation assay. The invasive potential of tumour cells was assessed using Matrigel invasion chambers, the cells' ability to migrate was determined with a wound-healing assay. To examine the biochemical activation of BKB2R, the epidermal growth factor receptor (EGFR) and its downstream pathways, western blot analyses were conducted. Immunohistochemistry revealed an over-expression of BKB2R in HNSCC tumour cells in comparison to normal peritumoural tissue. Blocking the BKB2R at irradiated tumour cells led to a reduced response to radiotherapy of tumour cells and led to an activation of the EGFR and its downstream pathways, known mediators of tumour cell survival, migration and invasion. Bradykinin stimulation also resulted in a better tumour cell survival, but these effects were achieved via an EGFR-independent signalling. Our results demonstrate that the kallikrein-kinin-system is involved in survival, invasion and migration of HNSCC cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. A motion-compensated image filter for low-dose fluoroscopy in a real-time tumor-tracking radiotherapy system

    PubMed Central

    Miyamoto, Naoki; Ishikawa, Masayori; Sutherland, Kenneth; Suzuki, Ryusuke; Matsuura, Taeko; Toramatsu, Chie; Takao, Seishin; Nihongi, Hideaki; Shimizu, Shinichi; Umegaki, Kikuo; Shirato, Hiroki

    2015-01-01

    In the real-time tumor-tracking radiotherapy system, a surrogate fiducial marker inserted in or near the tumor is detected by fluoroscopy to realize respiratory-gated radiotherapy. The imaging dose caused by fluoroscopy should be minimized. In this work, an image processing technique is proposed for tracing a moving marker in low-dose imaging. The proposed tracking technique is a combination of a motion-compensated recursive filter and template pattern matching. The proposed image filter can reduce motion artifacts resulting from the recursive process based on the determination of the region of interest for the next frame according to the current marker position in the fluoroscopic images. The effectiveness of the proposed technique and the expected clinical benefit were examined by phantom experimental studies with actual tumor trajectories generated from clinical patient data. It was demonstrated that the marker motion could be traced in low-dose imaging by applying the proposed algorithm with acceptable registration error and high pattern recognition score in all trajectories, although some trajectories were not able to be tracked with the conventional spatial filters or without image filters. The positional accuracy is expected to be kept within ±2 mm. The total computation time required to determine the marker position is a few milliseconds. The proposed image processing technique is applicable for imaging dose reduction. PMID:25129556

  3. Monitoring ABC-assisted deep inspiration breath hold for left-sided breast radiotherapy with an optical tracking system

    SciTech Connect

    Mittauer, Kathryn E.; Deraniyagala, Rohan; Li, Jonathan G.; Lu, Bo; Liu, Chihray; Samant, Sanjiv S.; Lightsey, Judith L.; Yan, Guanghua

    2015-01-15

    Purpose: Recent knowledge on the effects of cardiac toxicity warrants greater precision for left-sided breast radiotherapy. Different breath-hold (BH) maneuvers (abdominal vs thoracic breathing) can lead to chest wall positional variations, even though the patient’s tidal volume remains consistent. This study aims to investigate the feasibility of using optical tracking for real-time quality control of active breathing coordinator (ABC)-assisted deep inspiration BH (DIBH). Methods: An in-house optical tracking system (OTS) was used to monitor ABC-assisted DIBH. The stability and localization accuracy of the OTS were assessed with a ball-bearing phantom. Seven patients with left-sided breast cancer were included. A free-breathing (FB) computed tomography (CT) scan and an ABC-assisted BH CT scan were acquired for each patient. The OTS tracked an infrared (IR) marker affixed over the patient’s xiphoid process to measure the positional variation of each individual BH. Using the BH within which the CT scan was performed as the reference, the authors quantified intra- and interfraction BH variations for each patient. To estimate the dosimetric impact of BH variations, the authors studied the positional correlation between the marker and the left breast using the FB CT and BH CT scans. The positional variations of 860 BHs as measured by the OTS were retrospectively incorporated into the original treatment plans to evaluate their dosimetric impact on breast and cardiac organs [heart and left anterior descending (LAD) artery]. Results: The stability and localization accuracy of the OTS was within 0.2 mm along each direction. The mean intrafraction variation among treatment BHs was less than 2.8 mm in all directions. Up to 12.6 mm anteroposterior undershoot, where the patient’s chest wall displacement of a BH is less than that of a reference BH, was observed with averages of 4.4, 3.6, and 0.1 mm in the anteroposterior, craniocaudal, and mediolateral directions

  4. [Radiotherapy of skin cancers].

    PubMed

    Hennequin, C; Rio, E; Mahé, M-A

    2016-09-01

    The indications of radiotherapy for skin cancers are not clearly defined because of the lack of randomised trials or prospective studies. For basal cell carcinomas, radiotherapy frequently offers a good local control, but a randomized trial showed that surgery is more efficient and less toxic. Indications of radiotherapy are contra-indications of surgery for patients older than 60, non-sclerodermiform histology and occurring in non-sensitive areas. Adjuvant radiotherapy could be proposed to squamous cell carcinomas, in case of poor prognostic factors. Dose of 60 to 70Gy are usually required, and must be modulated to the size of the lesions. Adjuvant radiotherapy seems beneficial for desmoplastic melanomas but not for the other histological types. Prophylactic nodal irradiation (45 to 50Gy), for locally advanced tumours (massive nodal involvement), decreases the locoregional failure rate but do not increase survival. Adjuvant radiotherapy (50 to 56Gy) for Merckel cell carcinomas increases also the local control rate, as demonstrated by meta-analysis and a large epidemiological study. Nodal areas must be included, if there is no surgical exploration (sentinel lymph node dissection). Kaposi sarcomas are radiosensitive and could be treated with relatively low doses (24 to 30Gy). Also, cutaneous lymphomas are good indications for radiotherapy: B lymphomas are electively treated with limited fields. The role of total skin electron therapy for T-lymphomas is still discussed; but palliative radiotherapy is very efficient in case of cutaneous nodules.

  5. [Conformal radiotherapy for vertebral bone metastasis].

    PubMed

    Faivre, J C; Py, J F; Vogin, G; Martinage, G; Salleron, J; Royer, P; Grandgirard, N; Pasquier, D; Thureau, S

    2016-10-01

    Analgesic external beam radiation therapy is a standard of care for patients with uncomplicated painful bone metastases and/or prevention of bone complications. In case of fracture risk, radiation therapy is performed after surgery in a consolidation of an analgesic purpose and stabilizing osteosynthesis. Radiotherapy is mandatory after vertebroplasty or kyphoplasty. Spinal cord compression - the only emergency in radiation therapy - is indicated postoperatively either exclusively for non surgical indication. Analgesic re-irradiation is possible in the case of insufficient response or recurrent pain after radiotherapy. Metabolic radiation, bisphosphonates or denosumab do not dissuade external radiation therapy for pain relief. Systemic oncological treatments can be suspended with a period of wash out given the risk of radiosensitization or recall phenomenon. Better yet, the intensity modulated radiotherapy and stereotactic radiotherapy can be part of a curative strategy for oligometastatic patients and suggest new treatment prospects.

  6. Inhalation anesthesia in experimental radiotherapy: a reliable and time-saving system for multifractionation studies in a clinical department. [Rats; Mice

    SciTech Connect

    Ang, K.K.; Van Der Kogel, A.J.; Van Der Schueren, E.

    1982-01-01

    An inhalation anesthesia system has been employed to overcome several of the limitations associated wih the use of sodium pentobarbital and other i.p. administered anesthetics in experimental radiotherapy. The described method is reliable and time-saving. The depth and duration of anesthesia are easily controllable. Only 4 deaths have occurred with more than 6000 animal exposures. The use of polystyrene jigs is shown to provide adequate thermal isolation. Oxygen as a carrier of the anesthetic agent is expected to prevent a reduced tissue oxygenation and its radiobiologial consequences. The whole system is constructed as a mobile unit in which up to 16 mice or rats can be anesthetized simultaneously and irradiated in a single field with clinical treatment equipment during short time intervals between patient irradiations. The described advantages of this method make it specially suited for experiments with protracted fractionation schedules.

  7. Comparison of "sandwich chemo-radiotherapy" and six cycles of chemotherapy followed by adjuvant radiotherapy in patients with stage IIIC endometrial cancer: a single center experience.

    PubMed

    Dogan, Nasuh Utku; Yavas, Guler; Yavas, Cagdas; Ata, Ozlem; Yılmaz, Setenay Arzu; Celik, Cetin

    2013-10-01

    To compare "sandwich chemo-radiotherapy" with six cycles of chemotherapy followed by adjuvant radiotherapy with respect to tolerability and acute toxicity. Twenty-five women with surgically staged IIIC endometrial cancer were included. Treatment consisted of either three cycles of paclitaxel (175 mg/m²) and carboplatin (AUC 6) on a q21-day schedule followed by irradiation (45-50.4 Gy) or six cycles of the same chemotherapy followed by radiotherapy. Acute toxicity related to either chemotherapy or radiotherapy was evaluated. Median age was 61.5 years (range 36-83 years). Eleven patients had sandwich chemo-radiotherapy, and the other 14 patients had 6 cycles of chemotherapy followed by radiotherapy. Three out of the five patients who could not complete all the cycles in the sandwich chemo-radiotherapy group had pelvic and para-aortic radiotherapy. Acute radiotherapy related grade 1-2 gastrointestinal system (GIS) and genitourinary system (GUS) toxicities were observed in 72.8 and 63.6 % of patients, respectively, for sandwich group. Undesired treatment breaks in the course of radiotherapy were observed in six patients for sandwich chemo-radiotherapy and in one patient receiving six cycles of chemotherapy followed by radiotherapy. All the patients who had undesired treatment breaks in the sandwich chemo-radiotherapy group had pelvic and para-aortic radiotherapy. Sandwich chemo-radiotherapy seems to be more toxic particularly for patients who had pelvic and para-aortic irradiation. Therefore, it might be more convenient to delay radiotherapy after six cycles of chemotherapy for patients with the indication of pelvic para-aortic radiotherapy.

  8. [Prostate cancer external beam radiotherapy].

    PubMed

    de Crevoisier, R; Pommier, P; Latorzeff, I; Chapet, O; Chauvet, B; Hennequin, C

    2016-09-01

    The prostate external beam radiotherapy techniques are described, when irradiating the prostate or after prostatectomy, with and without pelvic lymph nodes. The following parts are presented: indications of radiotherapy, total dose and fractionation, planning CT image acquisition, volume of interest delineation (target volumes and organs at risk) and margins, Intensity modulated radiotherapy planning and corresponding dose-volume constraints, and finally Image guided radiotherapy.

  9. Chemoradiotherapy Versus Radiotherapy Alone in Stage II Nasopharyngeal Carcinoma: A Systemic Review and Meta-analysis of 2138 Patients

    PubMed Central

    Xu, Cheng; Zhang, Li-He; Chen, Yu-Pei; Liu, Xu; Zhou, Guan-Qun; Lin, Ai-Hua; Sun, Ying; Ma, Jun

    2017-01-01

    Background: To explore the value of chemoradiotherapy (CRT) in stage II nasopharyngeal carcinoma (NPC) compared to radiotherapy (RT) alone which includes two-dimensional radiotherapy (2D-RT) and intensity-modulated radiotherapy (IMRT). Methods:All topic-related comparative articles were identified by a comprehensive search of public databases (MEDLINE, EMBASE, Cochrane Library and CBMdisc). The primary outcomes were overall survival (OS), loco-regional relapse-free survival (LRRFS) and distant metastasis-free survival (DMFS). Secondary outcomes were grade 3-4 acute toxicity events. We performed subgroup analysis of CRT versus 2D-RT/IMRT alone to investigate the optimal modality. Sensitivity analysis focused on CRT versus IMRT alone was used to assess stability of the study results. Results:Eleven comparative studies (2138 patients) were eligible. CRT had significantly higher OS (HR = 0.67, 95% CI = 0.45-0.98, P = 0.04) and LRRFS (HR = 0.61, 95% CI = 0.46-0.80, P = 0.0003) than RT alone, but no significant difference was observed in DMFS (HR = 0.83, 95% CI = 0.52-1.31, P = 0.41). Meanwhile, CRT was associated with higher frequencies of grade 3-4 leukopenia, mucositis and nausea (P = 0.005, 0.03, < 0.0001, respectively). Subgroup analysis showed that IMRT alone could achieve equivalent OS, LRRFS and DMFS compared to CRT (P = 0.14, 0.06, 0.89, respectively). Significant value was only observed in LRRFS for CRT compared to 2D-RT alone (P = 0.01). Sensitivity analysis for the comparison of CRT and IMRT alone demonstrated generally stable outcomes, in support of the final conclusions. Conclusions:In the treatment of patients with stage II NPC, CRT was better than 2D-RT alone with significant benefit in LRRFS. IMRT alone was superior to CRT with equivalent survival outcomes and fewer grade 3-4 acute toxicities. PMID:28243333

  10. Hypofractionated stereotactic body radiotherapy for primary and metastatic liver tumors using the novalis image-guided system: preliminary results regarding efficacy and toxicity.

    PubMed

    Iwata, Hiromitsu; Shibamoto, Yuta; Hashizume, Chisa; Mori, Yoshimasa; Kobayashi, Tatsuya; Hayashi, Naoki; Kosaki, Katsura; Ishikawa, Tetsuya; Kuzuya, Teiji; Utsunomiya, Setsuo

    2010-12-01

    www.tcrt.org The purpose of this study was to evaluate the efficacy and toxicity of stereotactic body radiotherapy (SBRT) for primary and metastatic liver tumors using the Novalis image-guided radiotherapy system. After preliminarily treating liver tumors using the Novalis system from July 2006, we started a protocol-based study in February 2008. Eighteen patients (6 with primary hepatocellular carcinoma and 12 with metastatic liver tumor) were treated with 55 or 50 Gy, depending upon their planned dose distribution and liver function, delivered in 10 fractions over 2 weeks. Four non-coplanar and three coplanar static beams were used. Patient age ranged from 54 to 84 years (median: 72 years). The Child-Pugh classification was Grade A in 17 patients and Grade B in 1. Tumor diameter ranged from 12 to 35 mm (median: 23 mm). Toxicities were evaluated according to the Common Terminology Criteria of Adverse Events version 4.0, and radiation-induced liver disease (RILD) was defined by Lawrence's criterion. The median follow-up period was 14.5 months. For all patients, the 1-year overall survival and local control rates were 94% and 86%, respectively. A Grade 1 liver enzyme change was observed in 5 patients, but no RILD or chronic liver dysfunction was observed. SBRT using the Novalis image-guided system is safe and effective for treating primary and metastatic liver tumors. Further investigation of SBRT for liver tumors is warranted. In view of the acceptable toxicity observed with this protocol, we have moved to a new protocol to shorten the overall treatment time and escalate the dose.

  11. Comparison of Dosimetric Performance among Commercial Quality Assurance Systems for Verifying Pretreatment Plans of Stereotactic Body Radiotherapy Using Flattening-Filter-Free Beams

    PubMed Central

    2016-01-01

    The purpose of this study was to compare the performance of different commercial quality assurance (QA) systems for the pretreatment verification plan of stereotactic body radiotherapy (SBRT) with volumetric arc therapy (VMAT) technique using a flattening-filter-free beam. The verification for 20 pretreatment cancer patients (seven lung, six spine, and seven prostate cancers) were tested using three QA systems (EBT3 film, I’mRT MatriXX array, and MapCHECK). All the SBRT-VMAT plans were optimized in the Eclipse (version 11.0.34) treatment planning system (TPS) using the Acuros XB dose calculation algorithm and were delivered to the Varian TrueBeam® accelerator equipped with a high-definition multileaf collimator. Gamma agreement evaluation was analyzed with the criteria of 2% dose difference and 2 mm distance to agreement (2%/2 mm) or 3%/3 mm. The highest passing rate (99.1% for 3%/3 mm) was observed on the MapCHECK system while the lowest passing rate was obtained on the film. The pretreatment verification results depend on the QA systems, treatment sites, and delivery beam energies. However, the delivery QA results for all QA systems based on the TPS calculation showed a good agreement of more than 90% for both the criteria. It is concluded that the three 2D QA systems have sufficient potential for pretreatment verification of the SBRT-VMAT plan. PMID:27709851

  12. Initial application of a geometric QA tool for integrated MV and kV imaging systems on three image guided radiotherapy systems.

    PubMed

    Mao, Weihua; Speiser, Michael; Medin, Paul; Papiez, Lech; Solberg, Timothy; Xing, Lei

    2011-05-01

    Several linacs with integrated kilovoltage (kV) imaging have been developed for delivery of image guided radiation therapy (IGRT). High geometric accuracy and coincidence of kV imaging systems and megavoltage (MV) beam delivery are essential for successful image guidance. A geometric QA tool has been adapted for routine QA for evaluating and characterizing the geometric accuracy of kV and MV cone-beam imaging systems. The purpose of this work is to demonstrate the application of methodology to routine QA across three IGRT-dedicated linac platforms. It has been applied to a Varian Trilogy (Varian Medical Systems, Palo Alto, CA), an Elekta SynergyS (Elekta, Stockholm, Sweden), and a Brainlab Vero (Brainlab AG, Feldkirchen, Germany). Both the Trilogy and SynergyS linacs are equipped with a retractable kV x-ray tube and a flat panel detector. The Vero utilizes a rotating, rigid ring structure integrating a MV x-ray head mounted on orthogonal gimbals, an electronic portal imaging device (EPID), two kV x-ray tubes, and two fixed flat panel detectors. This dual kV imaging system provides orthogonal radiographs, CBCT images, and real-time fluoroscopic monitoring. Two QA phantoms were built to suit different field sizes. Projection images of a QA phantom were acquired using MV and kV imaging systems at a series of gantry angles. Software developed for this study was used to analyze the projection images and calculate nine geometric parameters for each projection. The Trilogy was characterized five times over one year, while the SynergyS was characterized four times and the Vero once. Over 6500 individual projections were acquired and analyzed. Quantitative geometric parameters of both MV and kV imaging systems, as well as the isocenter consistency of the imaging systems, were successfully evaluated. A geometric tool has been successfully implemented for calibration and QA of integrated kV and MV across a variety of radiotherapy platforms. X-ray source angle deviations up to

  13. Accuracy and efficiency of an infrared based positioning and tracking system for patient set-up and monitoring in image guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Jia, Jing; Xu, Gongming; Pei, Xi; Cao, Ruifen; Hu, Liqin; Wu, Yican

    2015-03-01

    An infrared based positioning and tracking (IPT) system was introduced and its accuracy and efficiency for patient setup and monitoring were tested for daily radiotherapy treatment. The IPT system consists of a pair of floor mounted infrared stereoscopic cameras, passive infrared markers and tools used for acquiring localization information as well as a custom controlled software which can perform the positioning and tracking functions. The evaluation of IPT system characteristics was conducted based on the AAPM 147 task report. Experiments on spatial drift and reproducibility as well as static and dynamic localization accuracy were carried out to test the efficiency of the IPT system. Measurements of known translational (up to 55.0 mm) set-up errors in three dimensions have been performed on a calibration phantom. The accuracy of positioning was evaluated on an anthropomorphic phantom with five markers attached to the surface; the precision of the tracking ability was investigated through a sinusoidal motion platform. For the monitoring of the respiration, three volunteers contributed to the breathing testing in real time. The spatial drift of the IPT system was 0.65 mm within 60 min to be stable. The reproducibility of position variations were between 0.01 and 0.04 mm. The standard deviation of static marker localization was 0.26 mm. The repositioning accuracy was 0.19 mm, 0.29 mm, and 0.53 mm in the left/right (L/R), superior/inferior (S/I) and anterior/posterior (A/P) directions, respectively. The measured dynamic accuracy was 0.57 mm and discrepancies measured for the respiratory motion tracking was better than 1 mm. The overall positioning accuracy of the IPT system was within 2 mm. In conclusion, the IPT system is an accurate and effective tool for assisting patient positioning in the treatment room. The characteristics of the IPT system can successfully meet the needs for real time external marker tracking and patient positioning as well as respiration

  14. Recruitment in Radiotherapy

    ERIC Educational Resources Information Center

    Deeley, T. J.; And Others

    1976-01-01

    The Faculty Board of Radiotherapy and Oncology of the Royal College of Radiobiologists surveyed the factors thought to influence recruitment into the specialty. Possible factors listed in replies of 36 questionnaires are offered. (LBH)

  15. Recruitment in Radiotherapy

    ERIC Educational Resources Information Center

    Deeley, T. J.; And Others

    1976-01-01

    The Faculty Board of Radiotherapy and Oncology of the Royal College of Radiobiologists surveyed the factors thought to influence recruitment into the specialty. Possible factors listed in replies of 36 questionnaires are offered. (LBH)

  16. Planning a Radiotherapy Department.

    PubMed

    van der Merwe, D

    2017-02-01

    The master planning of new radiotherapy facilities requires the input and engagement of a range of highly specialised professionals, both in the construction and health sector. Although radiation protection and safety aspects of radiotherapy services are universal, low and middle income countries are often presented with unique challenges that also need to be considered, e.g. competing needs within the health sector, lack of financial and human resources, environmental factors like poor provision of transport or electrical power, inadequate regulatory infrastructure, etc. Efforts to establish, upgrade or expand radiotherapy services should therefore not only focus on the technology that is appropriate and sustainable, but also be mindful of the need for quality, safety and optimal utilisation of technology. The workflow in a radiotherapy department can be facilitated by strategic placement of the main functional areas into the concept design. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  17. Reductions in the variations of respiration signals for respiratory-gated radiotherapy when using the video-coaching respiration guiding system

    NASA Astrophysics Data System (ADS)

    Lee, Hyun Jeong; Yea, Ji Woon; Oh, Se An

    2015-07-01

    Respiratory-gated radiation therapy (RGRT) has been used to minimize the dose to normal tissue in lung-cancer radiotherapy. The present research aims to improve the regularity of respiration in RGRT by using a video-coached respiration guiding system. In the study, 16 patients with lung cancer were evaluated. The respiration signals of the patients were measured by using a realtime position management (RPM) respiratory gating system (Varian, USA), and the patients were trained using the video-coaching respiration guiding system. The patients performed free breathing and guided breathing, and the respiratory cycles were acquired for ~5 min. Then, Microsoft Excel 2010 software was used to calculate the mean and the standard deviation for each phase. The standard deviation was computed in order to analyze the improvement in the respiratory regularity with respect to the period and the displacement. The standard deviation of the guided breathing decreased to 48.8% in the inhale peak and 24.2% in the exhale peak compared with the values for the free breathing of patient 6. The standard deviation of the respiratory cycle was found to be decreased when using the respiratory guiding system. The respiratory regularity was significantly improved when using the video-coaching respiration guiding system. Therefore, the system is useful for improving the accuracy and the efficiency of RGRT.

  18. Proton Radiotherapy for Liver Tumors: Dosimetric Advantages Over Photon Plans

    SciTech Connect

    Wang Xiaochun Krishnan, Sunil; Zhang Xiaodong; Dong Lei; Briere, Tina; Crane, Christopher H.; Martel, Mary; Gillin, Michael; Mohan, Radhe; Beddar, Sam

    2008-01-01

    The purpose of the study is to dosimetrically investigate the advantages of proton radiotherapy over photon radiotherapy for liver tumors. The proton plan and the photon plan were designed using commercial treatment planning systems. The treatment target dose conformity and heterogeneity and dose-volume analyses of normal structures were compared between proton and photon radiotherapy for 9 patients with liver tumors. Proton radiotherapy delivered a more conformal target dose with slightly less homogeneity when compared with photon radiotherapy. Protons significantly reduced the fractional volume of liver receiving dose greater or equal to 30 Gy (V{sub 30}) and the mean liver dose. The stomach and duodenal V{sub 45} were significantly lower with the use of proton radiotherapy. The V{sub 40} and V{sub 50} of the heart and the maximum spinal cord dose were also significantly lower with the use of proton radiotherapy. Protons were better able to spare one kidney completely and deliver less dose to one (generally the left) kidney than photons. The mean dose to the total body and most critical structures was significantly decreased using protons when compared to corresponding photon plans. In conclusion, our study suggests the dosimetric benefits of proton radiotherapy over photon radiotherapy. These dosimetric advantages of proton plans may permit further dose escalation with lower risk of complications.

  19. [Recent developments in radiotherapy of hepatocellular carcinoma].

    PubMed

    Seong, Jinsil

    2004-12-01

    With the accumulation of clinical experiences, the efficacy of radiotherapy has been recognized in management scheme for HCC. While hepatologists are beginning to show less reluctance for applying radiotherapy to the treatment of HCC, it is necessary that the hepatologists be informed of the rapid developments in technical strategy for radiation oncology. Recent advances in several technologies have opened a new era in radiation oncology. Modern imaging technologies can provide a 3-dimensional model of patient's anatomy, and this allows radiation oncologists to identify accurate tumor volumes as well as the tumors' relationship with the adjacent normal tissues. Moreover, the development of the computer-controlled multileaf collimator systems now enables physicians to perform precise beam shaping and to modulate the radiation dose distribution. A combination of these systems, 3-DCRT, is rapidly replacing the more conventional 2-D radiotherapy. 3-DCRT has evolved into a more sophisticated technology, intensity modulated radiotherapy (IMRT). In IMRT, with the powerful computer-aided optimization process, the radiation dose can be delivered to the target using highly complex isodose profiles. This new technology has been further developed into IGRT, which combines the CT-images scanning system and radiation equipments into one hardware package, and this system is currently ready for clinical application. In parallel with the radiation technologies described above, the strategy of stereotactic radiation has evolved from the conventional linear accelerator-based system to a gammaknife, and more recently, to a cyberknife. These systems are primarily based on the concept of radiosurgery. Currently, various radiation technologies have been adopted for the radiotherapy of HCC. In this article, each strategy will be discussed as well as the indications for radiotherapy and the radiation-related complications.

  20. Integrated radiotherapy imaging system (IRIS): design considerations of tumour tracking with linac gantry-mounted diagnostic x-ray systems with flat-panel detectors.

    PubMed

    Berbeco, Ross I; Jiang, Steve B; Sharp, Gregory C; Chen, George T; Mostafavi, Hassan; Shirato, Hiroki

    2004-01-21

    The design of an integrated radiotherapy imaging system (IRIS), consisting of gantry mounted diagnostic (kV) x-ray tubes and fast read-out flat-panel amorphous-silicon detectors, has been studied. The system is meant to be capable of three main functions: radiographs for three-dimensional (3D) patient set-up, cone-beam CT and real-time tumour/marker tracking. The goal of the current study is to determine whether one source/panel pair is sufficient for real-time tumour/marker tracking and, if two are needed, the optimal position of each relative to other components and the isocentre. A single gantry-mounted source/imager pair is certainly capable of the first two of the three functions listed above and may also be useful for the third, if combined with prior knowledge of the target's trajectory. This would be necessary because only motion in two dimensions is visible with a single imager/source system. However, with previously collected information about the trajectory, the third coordinate may be derived from the other two with sufficient accuracy to facilitate tracking. This deduction of the third coordinate can only be made if the 3D tumour/marker trajectory is consistent from fraction to fraction. The feasibility of tumour tracking with one source/imager pair has been theoretically examined here using measured lung marker trajectory data for seven patients from multiple treatment fractions. The patients' selection criteria include minimum mean amplitudes of the tumour motions greater than 1 cm peak-to-peak. The marker trajectory for each patient was modelled using the first fraction data. Then for the rest of the data, marker positions were derived from the imager projections at various gantry angles and compared with the measured tumour positions. Our results show that, due to the three dimensionality and irregular trajectory characteristics of tumour motion, on a fraction-to-fraction basis, a 'monoscopic' system (single source/imager) is inadequate for

  1. Integrated radiotherapy imaging system (IRIS): design considerations of tumour tracking with linac gantry-mounted diagnostic x-ray systems with flat-panel detectors

    NASA Astrophysics Data System (ADS)

    Berbeco, Ross I.; Jiang, Steve B.; Sharp, Gregory C.; Chen, George T. Y.; Mostafavi, Hassan; Shirato, Hiroki

    2004-01-01

    The design of an integrated radiotherapy imaging system (IRIS), consisting of gantry mounted diagnostic (kV) x-ray tubes and fast read-out flat-panel amorphous-silicon detectors, has been studied. The system is meant to be capable of three main functions: radiographs for three-dimensional (3D) patient set-up, cone-beam CT and real-time tumour/marker tracking. The goal of the current study is to determine whether one source/panel pair is sufficient for real-time tumour/marker tracking and, if two are needed, the optimal position of each relative to other components and the isocentre. A single gantry-mounted source/imager pair is certainly capable of the first two of the three functions listed above and may also be useful for the third, if combined with prior knowledge of the target's trajectory. This would be necessary because only motion in two dimensions is visible with a single imager/source system. However, with previously collected information about the trajectory, the third coordinate may be derived from the other two with sufficient accuracy to facilitate tracking. This deduction of the third coordinate can only be made if the 3D tumour/marker trajectory is consistent from fraction to fraction. The feasibility of tumour tracking with one source/imager pair has been theoretically examined here using measured lung marker trajectory data for seven patients from multiple treatment fractions. The patients' selection criteria include minimum mean amplitudes of the tumour motions greater than 1 cm peak-to-peak. The marker trajectory for each patient was modelled using the first fraction data. Then for the rest of the data, marker positions were derived from the imager projections at various gantry angles and compared with the measured tumour positions. Our results show that, due to the three dimensionality and irregular trajectory characteristics of tumour motion, on a fraction-to-fraction basis, a 'monoscopic' system (single source/imager) is inadequate for

  2. Evaluation of a combined respiratory-gating system comprising the TrueBeam linear accelerator and a new real-time tumor-tracking radiotherapy system: a preliminary study.

    PubMed

    Shiinoki, Takehiro; Kawamura, Shinji; Uehara, Takuya; Yuasa, Yuki; Fujimoto, Koya; Koike, Masahiro; Sera, Tatsuhiro; Emoto, Yuki; Hanazawa, Hideki; Shibuya, Keiko

    2016-07-01

    A combined system comprising the TrueBeam linear accelerator and a new real-time, tumor-tracking radiotherapy system, SyncTraX, was installed in our institution. The goals of this study were to assess the capability of SyncTraX in measuring the position of a fiducial marker using color fluoroscopic images, and to evaluate the dosimetric and geometric accuracy of respiratory-gated radiotherapy using this combined system for the simple geometry. For the fundamental evaluation of respiratory-gated radiotherapy using SyncTraX, the following were performed: 1) determination of dosimetric and positional characteristics of sinusoidal patterns using a motor-driven base for several gating windows; 2) measurement of time delay using an oscilloscope; 3) positional verification of sinusoidal patterns and the pattern in the case of a lung cancer patient; 4) measurement of the half-value layer (HVL in mm AL), effective kVp, and air kerma, using a solid-state detector for each fluoroscopic condition, to determine the patient dose. The dose profile in a moving phantom with gated radiotherapy having a gating window ≤4 mm was in good agreement with that under static conditions for each photon beam. The total time delay between TrueBeam and SyncTraX was <227 ms for each photon beam. The mean of the positional tracking error was <0.4 mm for sinusoidal patterns and for the pattern in the case of a lung cancer patient. The air-kerma rates from one fluoroscopy direction were 1.93±0.01, 2.86±0.01, 3.92±0.04, 5.28±0.03, and 6.60±0.05 mGy/min for 70, 80, 90, 100, and 110 kV X-ray beams at 80 mA, respectively. The combined system comprising TrueBeam and SyncTraX could track the motion of the fiducial marker and control radiation delivery with reasonable accuracy; therefore, this system provides significant dosimetric improvement. However, patient exposure dose from fluoroscopy was not clinically negligible. PACS number(s): 87.53.Bn, 87.55.km, 87.55.Qr. © 2016 The Authors.

  3. Case report of a near medical event in stereotactic radiotherapy due to improper units of measure from a treatment planning system.

    PubMed

    Gladstone, D J; Li, S; Jarvis, L A; Hartford, A C

    2011-07-01

    The authors hereby notify the Radiation Oncology community of a potentially lethal error due to improper implementation of linear units of measure in a treatment planning system. The authors report an incident in which a patient was nearly mistreated during a stereotactic radiotherapy procedure due to inappropriate reporting of stereotactic coordinates by the radiation therapy treatment planning system in units of centimeter rather than in millimeter. The authors suggest a method to detect such errors during treatment planning so they are caught and corrected prior to the patient positioning for treatment on the treatment machine. Using pretreatment imaging, the authors found that stereotactic coordinates are reported with improper linear units by a treatment planning system. The authors have implemented a redundant, independent method of stereotactic coordinate calculation. Implementation of a double check of stereotactic coordinates via redundant, independent calculation is simple and accurate. Use of this technique will avoid any future error in stereotactic treatment coordinates due to improper linear units, transcription, or other similar errors. The authors recommend an independent double check of stereotactic treatment coordinates during the treatment planning process in order to avoid potential mistreatment of patients.

  4. Case report of a near medical event in stereotactic radiotherapy due to improper units of measure from a treatment planning system

    SciTech Connect

    Gladstone, D. J.; Li, S.; Jarvis, L. A.; Hartford, A. C.

    2011-07-15

    Purpose: The authors hereby notify the Radiation Oncology community of a potentially lethal error due to improper implementation of linear units of measure in a treatment planning system. The authors report an incident in which a patient was nearly mistreated during a stereotactic radiotherapy procedure due to inappropriate reporting of stereotactic coordinates by the radiation therapy treatment planning system in units of centimeter rather than in millimeter. The authors suggest a method to detect such errors during treatment planning so they are caught and corrected prior to the patient positioning for treatment on the treatment machine. Methods: Using pretreatment imaging, the authors found that stereotactic coordinates are reported with improper linear units by a treatment planning system. The authors have implemented a redundant, independent method of stereotactic coordinate calculation. Results: Implementation of a double check of stereotactic coordinates via redundant, independent calculation is simple and accurate. Use of this technique will avoid any future error in stereotactic treatment coordinates due to improper linear units, transcription, or other similar errors. Conclusions: The authors recommend an independent double check of stereotactic treatment coordinates during the treatment planning process in order to avoid potential mistreatment of patients.

  5. An imaging informatics-based system utilizing DICOM objects for treating pain in spinal cord injury patients utilizing proton beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Verma, Sneha K.; Liu, Brent J.; Chun, Sophia; Gridley, Daila S.

    2014-03-01

    Many US combat personnel have sustained nervous tissue trauma during service, which often causes Neuropathic pain as a side effect and is difficult to manage. However in select patients, synapse lesioning can provide significant pain control. Our goal is to determine the effectiveness of using Proton Beam radiotherapy for treating spinal cord injury (SCI) related neuropathic pain as an alternative to invasive surgical lesioning. The project is a joint collaboration of USC, Spinal Cord Institute VA Healthcare System, Long Beach, and Loma Linda University. This is first system of its kind that supports integration and standardization of imaging informatics data in DICOM format; clinical evaluation forms outcomes data and treatment planning data from the Treatment planning station (TPS) utilized to administer the proton therapy in DICOM-RT format. It also supports evaluation of SCI subjects for recruitment into the clinical study, which includes the development, and integration of digital forms and tools for automatic evaluation and classification of SCI pain. Last year, we presented the concept for the patient recruitment module based on the principle of Bayesian decision theory. This year we are presenting the fully developed patient recruitment module and its integration to other modules. In addition, the DICOM module for integrating DICOM and DICOM-RT-ION data is also developed and integrated. This allows researchers to upload animal/patient study data into the system. The patient recruitment module has been tested using 25 retrospective patient data and DICOM data module is tested using 5 sets of animal data.

  6. 2D/3D Image fusion for accurate target localization and evaluation of a mask based stereotactic system in fractionated stereotactic radiotherapy of cranial lesions

    SciTech Connect

    Jin, J.-Y.; Ryu, Samuel; Faber, Kathleen; Mikkelsen, Tom; Chen Qing; Li Shidong; Movsas, Benjamin

    2006-12-15

    The purpose of this study was to evaluate the accuracy of a two-dimensional (2D) to three-dimensional (3D) image-fusion-guided target localization system and a mask based stereotactic system for fractionated stereotactic radiotherapy (FSRT) of cranial lesions. A commercial x-ray image guidance system originally developed for extracranial radiosurgery was used for FSRT of cranial lesions. The localization accuracy was quantitatively evaluated with an anthropomorphic head phantom implanted with eight small radiopaque markers (BBs) in different locations. The accuracy and its clinical reliability were also qualitatively evaluated for a total of 127 fractions in 12 patients with both kV x-ray images and MV portal films. The image-guided system was then used as a standard to evaluate the overall uncertainty and reproducibility of the head mask based stereotactic system in these patients. The phantom study demonstrated that the maximal random error of the image-guided target localization was {+-}0.6 mm in each direction in terms of the 95% confidence interval (CI). The systematic error varied with measurement methods. It was approximately 0.4 mm, mainly in the longitudinal direction, for the kV x-ray method. There was a 0.5 mm systematic difference, primarily in the lateral direction, between the kV x-ray and the MV portal methods. The patient study suggested that the accuracy of the image-guided system in patients was comparable to that in the phantom. The overall uncertainty of the mask system was {+-}4 mm, and the reproducibility was {+-}2.9 mm in terms of 95% CI. The study demonstrated that the image guidance system provides accurate and precise target positioning.

  7. Determination of patient set-up error and optimal treatment margin for intensity modulated radiotherapy using image guidance system.

    PubMed

    Kanakavelu, Nithya; Jebaseelan Samuel, James

    2016-01-01

    The geometrical uncertainties in the patient positioning during intensity modulated radiotherapy (IMRT) are crucial as there is potential to underdose the tumor and overdose the nearby critical structures. Image guided techniques provide a solution to assess the patient set-up uncertainties and help determine the optimal planning target volume (PTV) margin to the clinical tumor volume (CTV). A retrospective study was conducted to evaluate patient set-up errors along the three translational directions at different treatment sites such as the brain, the head and neck (H&N) and the prostate. A total of 60 patients' set-up error data was analysed to evaluate the systematic and random errors and the optimal CTV-PTV margin. For brain and H&N sites, more than 90, 80 and about 100% of the total image acquisitions were less than 3 mm in lateral, longitudinal and vertical directions respectively. For the prostate cases, the frequency of patient set-up error to be less than 3 mm were 79.7, 75.6 and 80% in lateral, longitudinal and vertical directions respectively. About 0.6% had more than 7 mm error in the lateral and longitudinal directions for the prostate site. CTV-PTV margin of 3.4, 3.4 and 1.9 mm for brain cases, 3.5, 3 and 1.8 mm for H&N cases and 5, 4.6 and 4.5 mm for the prostate cases in the lateral, longitudinal and vertical directions respectively were determined. Image guidance is an effective method to evaluate the accuracy of IMRT treatment delivery. The optimal CTV-PTV margin can be determined to ensure adequate dose to CTV, specific to the site.

  8. Anti-inflammatory effects of low-dose radiotherapy in an experimental model of systemic inflammation in mice

    SciTech Connect

    Arenas, Meritxell; Gil, Felix B.A.; Gironella, Meritxell; Hernandez, Victor; Jorcano, Sandra; Biete, Albert; Pique, Josep M.; Panes, Julian . E-mail: jpanes@clinic.ub.es

    2006-10-01

    Purpose: The aim of this study was to determine the effects of low-dose radiotherapy (LD-RT) on the inflammatory response and to characterize the potential mechanisms underlying these effects. Methods and Materials: Mice were irradiated with 0.1, 0.3, 0.6 Gy, or sham radiation before lipopolysaccharide (LPS) challenge. Leukocyte-endothelial cell interactions in intestinal venules were assessed using intravital microscopy. Intercellular adhesion molecule-1 (ICAM-1) expression was determined using radiolabeled antibodies 5 h after irradiation. Production of transforming growth factor-{beta}{sub 1} (TGF-{beta}{sub 1}) was measured by enzyme-linked immunosorbent assay and its in vivo functional relevance by immunoneutralization. Results: Compared with vehicle treated animals, LPS induced a marked increase in leukocyte adhesion (0.13 {+-} 0.59 vs. 5.89 {+-} 1.03, p < 0.0001) in intestinal venules. The number of adherent leukocytes was significantly reduced by the 3 doses of LD-RT tested; the highest inhibition was observed with 0.3 Gy (0.66 {+-} 1.96, p < 0.0001). LPS-induced ICAM-1 upregulation was not modified by LD-RT. Circulating levels of TGF-{beta}{sub 1} were significantly increased in response to LD-RT in controls and LPS challenged animals. Neutralization of TGF-{beta}{sub 1} partially restored LPS-induced adhesion (4.83 {+-} 1.41, p < 0.05). Conclusions: LD-RT has a significant anti-inflammatory effect, inhibiting leukocyte recruitment, which is maximal at 0.3 Gy. This effect results in part from increased TGF-{beta}{sub 1} production and is not related to modulation of ICAM-1 expression.

  9. Direct tumor in vivo dosimetry in highly-conformal radiotherapy: A feasibility study of implantable MOSFETs for hypofractionated extracranial treatments using the Cyberknife system

    SciTech Connect

    Scalchi, Paolo; Righetto, Roberto; Cavedon, Carlo; Francescon, Paolo; Colombo, Federico

    2010-04-15

    Purpose: In highly-conformal radiotherapy, due to the complexity of both beam configurations and dose distributions, traditional in vivo dosimetry is unpractical or even impossible. The ideal dosimeter would be implanted inside the planning treatment volume so that it can directly measure the total delivered dose during each fraction with no additional uncertainty due to calculation models. The aim of this work is to verify if implantable metal oxide semiconductors field effect transistors (MOSFETs) can achieve a sufficient degree of dosimetric accuracy when used inside extracranial targets undergoing radiotherapy treatments using the Cyberknife system. Methods: Based on the preliminary findings of this study, new prototypes for high dose fractionations were developed to reduce the time dependence for long treatment delivery times. These dosimeters were recently cleared and are marketed as DVS-HFT. Multiple measurements were performed using both Virtual Water and water phantoms to characterize implantable MOSFETs under the Cyberknife beams, and included the reference-dosimetry consistency, the dependence of the response on the collimator size, on the daily delivered dose, and the time irradiation modality. Finally a Cyberknife prostate treatment simulation using a body phantom was conducted, and both MOSFET and ionization readings were compared to Monte Carlo calculations. The feasibility analysis was conducted based on the ratios of the absorbed dose divided by the dose reading, named as ''further calibration factor'' (FCF). Results: The average FCFs resulted to be 0.98 for the collimator dependence test, and about 1.00 for the reference-dosimetry test, the dose-dependence test, and the time-dependence test. The average FCF of the prostate treatment simulation test was 0.99. Conclusions: The obtained results are well within DVS specifications, that is, the factory calibration is still valid for such kind of treatments using the Cyberknife system, with no need of

  10. [Radiotherapy of larynx cancers].

    PubMed

    Pointreau, Y; Lafond, C; Legouté, F; Trémolières, P; Servagi-Vernat, S; Giraud, P; Maingon, P; Calais, G; Lapeyre, M

    2016-09-01

    Intensity-modulated radiotherapy is the gold standard in the treatment of larynx cancers (except T1 glottic tumour). Early T1 and T2 tumours may be treated by exclusive radiation or surgery. For tumours requiring total laryngectomy (T2 or T3), induction chemotherapy followed by exclusive radiotherapy or concurrent chemoradiotherapy is possible. For T4 tumour, surgery must be proposed. The treatment of lymph nodes is based on the initial treatment of the primary tumour. In non-surgical procedure, in case of sequential radiotherapy, the curative dose is 70Gy and the prophylactic dose is 50Gy. An integrated simultaneous boost radiotherapy is allowed (70Gy in 2Gy per fraction and 56Gy in 1.8Gy per fraction or 70Gy in 2.12Gy per fraction). Postoperatively, radiotherapy is used in locally advanced cancer with dose levels based on pathologic criteria (66Gy for R1 resection, 50 to 54Gy for complete resection). Volume delineation was based on guidelines.

  11. [Radiotherapy for retroperitoneal sarcomas].

    PubMed

    Sargos, P; Stoeckle, E; Henriques de Figueiredo, B; Antoine, M; Delannes, M; Mervoyer, A; Kantor, G

    2016-10-01

    The management of retroperitoneal sarcoma can be very challenging, and the quality of initial treatment strategy appears to be a crucial prognostic factor. En bloc surgery is currently the standard of care for these rare tumours and perioperative treatments such as chemotherapy or radiotherapy have not been validated yet. However, local-regional relapse constitutes the most common disease course. While adjuvant radiotherapy is less and less common due to gastrointestinal toxicities, preoperative radiation therapy offers numerous advantages and is being evaluated as part of a national multicentre phase II study (TOMOREP trial) and is the subject of a European randomized phase III study (STRASS trial). The objective of this article is to present data on preoperative irradiation in terms of dose, volumes and optimal radiotherapy techniques for the treatment of this rare disease.

  12. Novel Luciferase-Based Reporter System to Monitor Activation of ErbB2/Her2/neu Pathway Noninvasively During Radiotherapy

    SciTech Connect

    Wolf, Frank; Li Wenrong; Li Fang; Li Chuanyuan

    2011-01-01

    Purpose: To develop a split-luciferase-based reporter system that allows for noninvasive monitoring of activation of the Her2/neu pathway in vivo in a quantitative and sensitive manner. Methods and Materials: Fusion proteins of the ErbB2/Her2/neu receptor to the N-terminal fragment of luciferase and of its downstream binding partner Shc to the C-terminal fragment of luciferase have been engineered owing to the rationale that on activation and binding of the Her2 receptor molecule to Shc, luciferase function will be reconstituted. Thus, the resulting bioluminescence signals can serve as a surrogate measure of receptor activation. Results: We have shown that our reporter systems functions well in vitro in breast cancer cells and in vivo in xenograft tumors. In particular, the activities of Her2/neu in xenograft tumors could be monitored serially for an extended period after radiotherapy. Conclusions: We believe that the novel ErbB2/Her2/neu reporter we have presented is a powerful tool to study the biology of the Her2-neu pathway in vitro and in vivo. It should also facilitate the development and rapid evaluation of new Her2/neu-targeted therapeutic agents.

  13. A novel luciferase based reporter system to monitor activation of the ErbB2/Her2/neu pathway non-invasively during radiotherapy

    PubMed Central

    Wolf, Frank; Li, Wenrong; Li, Fang; Li, Chuan-Yuan

    2010-01-01

    Purpose To develop a split-luciferase based reporter system that allows for non-invasive monitoring of activation of the Her2/neu pathway in vivo in a quantitative and sensitive manner. Methods and Materials Fusion proteins of the ErbB2/Her2/neu receptor to the N-terminal fragment of luciferase as well as of its downstream binding partner Shc to the C-terminal fragment of luciferase have been engineered based on the rationale that upon activation and binding of the Her2 receptor molecule to Shc, luciferase function will be reconstituted. Thus the resulting bioluminescence signals can serve as a surrogate measure of receptor activation. Results We show that our reporter systems functions well in vitro in breast cancer cells and in vivo in xenograft tumors. In particular, the activities of Her2/neu in xenograft tumors could be monitored serially for an extended period of time after radiotherapy. Conclusions We believe that the novel ErbB2/Her2/neu reporter presented here is a powerful tool to study the biology of the Her2-neu pathway in vitro as well as in vivo. It should also facilitate the development and rapid evaluation of new Her2/neu targeted therapeutics. PMID:20934271

  14. Radiotherapy for lung cancer

    SciTech Connect

    Bleehen, N.M.; Cox, J.D.

    1985-05-01

    The role of radiation therapy in the management of lung cancer was reviewed at a workshop held in Cambridge, England, in June 1984. It was concluded that there was a continuing role for radiation therapy in the primary management of small cell lung cancer, including the loco-regional treatment for patients with limited disease. Radical radiotherapy for patients with non-small cell carcinoma could be curative for a proportion of patients with limited disease. Careful planning and quality control was essential. Palliative radiotherapy provided useful treatment for many other patients. Other related aspects of treatment are also presented.

  15. SU-E-J-210: Characterizing Tissue Equivalent Materials for the Development of a Dual MRI-CT Heterogeneous Anthropomorphic Phantom Designed Specifically for MRI Guided Radiotherapy Systems

    SciTech Connect

    Steinmann, A; Stafford, R; Yung, J; Followill, D

    2015-06-15

    Purpose: MRI guided radiotherapy (MRIgRT) is an emerging technology which will eventually require a proficient quality auditing system. Due to different principles in which MR and CT acquire images, there is a need for a multi-imaging-modality, end-to-end QA phantom for MRIgRT. The purpose of this study is to identify lung, soft tissue, and tumor equivalent substitutes that share similar human-like CT and MR properties (i.e. Hounsfield units and relaxation times). Methods: Materials of interested such as common CT QA phantom materials, and other proprietary gels/silicones from Polytek, SmoothOn, and CompositeOne were first scanned on a GE 1.5T Signa HDxT MR. Materials that could be seen on both T1-weighted and T2-weighted images were then scanned on a GE Lightspeed RT16 CT simulator and a GE Discovery 750HD CT scanner and their HU values were then measured. The materials with matching HU values of lung (−500 to −700HU), muscle (+40HU) and soft tissue (+100 to +300HU) were further scanned on GE 1.5T Signa HDx to measure their T1 and T2 relaxation times from varying parameters of TI and TE. Results: Materials that could be visualized on T1-weighted and T2-weighted images from a 1.5T MR unit and had an appropriate average CT number, −650, −685, 46,169, and 168 HUs were: compressed cork saturated with water, Polytek Platsil™ Gel-00 combined with mini styrofoam balls, radiotherapy bolus material, SmoothOn Dragon-Skin™ and SmoothOn Ecoflex™, respectively. Conclusion: Post processing analysis is currently being performed to accurately map T1 and T2 values for each material tested. From previous MR visualization and CT examinations it is expected that Dragon-Skin™, Ecoflex™ and bolus will have values consistent with tissue and tumor substitutes. We also expect compressed cork statured with water, and Polytek™-styrofoam combination to have approximate T1 and T2 values suitable for lung-equivalent materials.

  16. Stereotactic body radiotherapy for lung cancer: how much does it really cost?

    PubMed

    Lievens, Yolande; Obyn, Caroline; Mertens, Anne-Sophie; Van Halewyck, Dries; Hulstaert, Frank

    2015-03-01

    Despite the lack of randomized evidence, stereotactic body radiotherapy (SBRT) is being accepted as superior to conventional radiotherapy for patients with T1-2N0 non-small-cell lung cancer in the periphery of the lung and unfit or unwilling to undergo surgery. To introduce SBRT in a system of coverage with evidence development, a correct financing had to be determined. A time-driven activity-based costing model for radiotherapy was developed. Resource cost calculation of all radiotherapy treatments, standard and innovative, was conducted in 10 Belgian radiotherapy centers in the second half of 2012. The average cost of lung SBRT across the 10 centers (6221&OV0556;) is in the range of the average costs of standard fractionated 3D-conformal radiotherapy (5919&OV0556;) and intensity-modulated radiotherapy (7379&OV0556;) for lung cancer. Hypofractionated 3D-conformal radiotherapy and intensity-modulated radiotherapy schemes are less costly (3993&OV0556; respectively 4730&OV0556;). The SBRT cost increases with the number of fractions and is highly dependent of personnel and equipment use. SBRT cost varies more by centre than conventional radiotherapy cost, reflecting different technologies, stages in the learning curve and a lack of clear guidance in this field. Time-driven activity-based costing of radiotherapy is feasible in a multicentre setup, resulting in real-life resource costs that can form the basis for correct reimbursement schemes, supporting an early yet controlled introduction of innovative radiotherapy techniques in clinical practice.

  17. [Recurrent breast cancer obtained long-term survival with local treatment(surgery and stereotactic body radiotherapy)and systemic therapy].

    PubMed

    Morioka, Emi; Ohno, Yukako; Noguchi, Miki; Nakano, Yasuharu; Noguchi, Masakuni; Kosaka, Takeo; Takanaka, Tsuyoshi

    2012-11-01

    A 52-year-old woman developed right breast cancer and underwent modified radical mastectomy in 1994. Histologically, the tumor was invasive ductal carcinoma. She was positive for estrogen receptor (ER) but negative for progesterone receptor(PgR), while her human epidermal growth factor receptor type 2(HER2) status was not examined. Although she received adjuvant hormone therapy and chemotherapy[cyclophosphamide+doxorubicin+5-fluorouraci(l CAF), 6 courses ], she underwent partial pulmonary resection on both sides with right oophorectomy in 1997. Subsequently, she was treated with weekly doses paclitaxel(12 courses). However, she developed a pulmonary metastasis in the left breast. In 2002, she underwent a partial left pulmonary resection (ER-positive and HER2 3+) and treatment with an aromatase inhibitor. Subsequently, she was treated with trastuzumab because of repeated lung metastasis. A complete response was obtained after the administration of trastuzumab. In 2008, she developed bone metastasis in the sternum and the left seventh rib, and subsequently underwent stereotactic body radiotherapy (SBRT). She was treated with trastuzumab and aromatase inhibitor. At present, she is free of pain and is still living 15 years after breast cancer recurrence. This case suggests that the interaction of local treatment(surgery and SBRT) and systemic therapy(chemotherapy, hormonal therapy, and monoclonal therapy) may improve the survival of patients with recurrent breast cancer.

  18. Phase I study of intraoperative radiotherapy with photon radiosurgery system in children with recurrent brain tumors: Preliminary report of first dose level (10 Gy)

    SciTech Connect

    Kalapurakal, John A. . E-mail: j-kalapurakal@northwestern.edu; Goldman, Stewart; Stellpflug, Wendy; Curran, John; Sathiaseelan, Vythialingam; Marymont, Maryanne H.; Tomita, Tadanori

    2006-07-01

    Purpose: To describe the preliminary results after intraoperative radiotherapy (IORT) with the photon radiosurgery system in children with recurrent brain tumors treated at the first dose level (10 Gy) of a Phase I protocol. Methods and Materials: A Phase I IORT dose escalation protocol was initiated at Children's Memorial Hospital to determine the maximal tolerated IORT dose in children with recurrent brain tumors. Results: Fourteen children have received IORT thus far. Eight had been previously irradiated. Thirteen children had ependymoma. The median follow-up was 16 months. Three patients (21%) developed radiation necrosis on follow-up MRI scans 6 to 12 months after IORT. They had not been previously irradiated and had received 10 Gy to a depth of 5 mm. One required surgery and the other two had resolution of their lesions without treatment. All 3 patients were asymptomatic at the last follow-up. No other late toxicity was observed at the last follow-up visit. Eight patients (57%) had tumor control within the surgical bed after IORT. Conclusion: Our findings have demonstrated the safety and feasibility of IORT to a dose of 10 Gy to 2 mm in children with previously irradiated brain tumors. IORT to a dose of 10 Gy at 5 mm was associated with a greater complication rate.

  19. Contact radiotherapy using a 50 kV X-ray system: Evaluation of relative dose distribution with the Monte Carlo code PENELOPE and comparison with measurements

    NASA Astrophysics Data System (ADS)

    Croce, Olivier; Hachem, Sabet; Franchisseur, Eric; Marcié, Serge; Gérard, Jean-Pierre; Bordy, Jean-Marc

    2012-06-01

    This paper presents a dosimetric study concerning the system named "Papillon 50" used in the department of radiotherapy of the Centre Antoine-Lacassagne, Nice, France. The machine provides a 50 kVp X-ray beam, currently used to treat rectal cancers. The system can be mounted with various applicators of different diameters or shapes. These applicators can be fixed over the main rod tube of the unit in order to deliver the prescribed absorbed dose into the tumor with an optimal distribution. We have analyzed depth dose curves and dose profiles for the naked tube and for a set of three applicators. Dose measurements were made with an ionization chamber (PTW type 23342) and Gafchromic films (EBT2). We have also compared the measurements with simulations performed using the Monte Carlo code PENELOPE. Simulations were performed with a detailed geometrical description of the experimental setup and with enough statistics. Results of simulations are made in accordance with experimental measurements and provide an accurate evaluation of the dose delivered. The depths of the 50% isodose in water for the various applicators are 4.0, 6.0, 6.6 and 7.1 mm. The Monte Carlo PENELOPE simulations are in accordance with the measurements for a 50 kV X-ray system. Simulations are able to confirm the measurements provided by Gafchromic films or ionization chambers. Results also demonstrate that Monte Carlo simulations could be helpful to validate the future applicators designed for other localizations such as breast or skin cancers. Furthermore, Monte Carlo simulations could be a reliable alternative for a rapid evaluation of the dose delivered by such a system that uses multiple designs of applicators.

  20. Poster — Thur Eve — 23: Dose and Position Quality Assurance using the RADPOS System for 4D Radiotherapy with CyberKnife

    SciTech Connect

    Marants, R; Vandervoort, E; Cygler, J E

    2014-08-15

    Introduction: RADPOS 4D dosimetry system consists of a microMOSFET dosimeter combined with an electromagnetic positioning sensor, which allows for performing real-time dose and position measurements simultaneously. In this report the use of RADPOS as an independent quality assurance (QA) tool during CyberKnife 4D radiotherapy treatment is described. In addition to RADPOS, GAFCHROMIC® films were used for simultaneous dose measurement. Methods: RADPOS and films were calibrated in a Solid Water® phantom at 1.5 cm depth, SAD= 80 cm, using 60 mm cone. CT based treatment plan was created for a Solid Water® breast phantom containing metal fiducials and RADPOS probe. Dose calculations were performed using iPlan pencil beam algorithm. Before the treatment delivery, GAFCHROMIC® film was inserted inside the breast phantom, next to the RADPOS probe. Then the phantom was positioned on the chest platform of the QUASAR, to which Synchrony LED optical markers were also attached. Position logging began for RADPOS and the Synchrony tracking system, the QUASAR motion was initiated and the treatment was delivered. Results: RADPOS position measurements very closely matched the LED marker positions recorded by the Synchrony camera tracking system. The RADPOS measured dose was 2.5% higher than the average film measured dose, which is within the experimental uncertainties. Treatment plan calculated dose was 4.1 and 1.6% lower than measured by RADPOS and film, respectively. This is most likely due to the inferior nature of the dose calculation algorithm. Conclusions: Our study demonstrates that RADPOS system is a useful tool for independent QA of CyberKnife treatments.

  1. Innovations in Radiotherapy Technology.

    PubMed

    Feain, I J; Court, L; Palta, J R; Beddar, S; Keall, P

    2017-02-01

    Many low- and middle-income countries, together with remote and low socioeconomic populations within high-income countries, lack the resources and services to deal with cancer. The challenges in upgrading or introducing the necessary services are enormous, from screening and diagnosis to radiotherapy planning/treatment and quality assurance. There are severe shortages not only in equipment, but also in the capacity to train, recruit and retain staff as well as in their ongoing professional development via effective international peer-review and collaboration. Here we describe some examples of emerging technology innovations based on real-time software and cloud-based capabilities that have the potential to redress some of these areas. These include: (i) automatic treatment planning to reduce physics staffing shortages, (ii) real-time image-guided adaptive radiotherapy technologies, (iii) fixed-beam radiotherapy treatment units that use patient (rather than gantry) rotation to reduce infrastructure costs and staff-to-patient ratios, (iv) cloud-based infrastructure programmes to facilitate international collaboration and quality assurance and (v) high dose rate mobile cobalt brachytherapy techniques for intraoperative radiotherapy. Copyright © 2016 The Royal College of Radiologists. All rights reserved.

  2. Precision radiotherapy for brain tumors

    PubMed Central

    Yan, Ying; Guo, Zhanwen; Zhang, Haibo; Wang, Ning; Xu, Ying

    2012-01-01

    OBJECTIVE: Precision radiotherapy plays an important role in the management of brain tumors. This study aimed to identify global research trends in precision radiotherapy for brain tumors using a bibliometric analysis of the Web of Science. DATA RETRIEVAL: We performed a bibliometric analysis of data retrievals for precision radiotherapy for brain tumors containing the key words cerebral tumor, brain tumor, intensity-modulated radiotherapy, stereotactic body radiation therapy, stereotactic ablative radiotherapy, imaging-guided radiotherapy, dose-guided radiotherapy, stereotactic brachytherapy, and stereotactic radiotherapy using the Web of Science. SELECTION CRITERIA: Inclusion criteria: (a) peer-reviewed articles on precision radiotherapy for brain tumors which were published and indexed in the Web of Science; (b) type of articles: original research articles and reviews; (c) year of publication: 2002-2011. Exclusion criteria: (a) articles that required manual searching or telephone access; (b) Corrected papers or book chapters. MAIN OUTCOME MEASURES: (1) Annual publication output; (2) distribution according to country; (3) distribution according to institution; (4) top cited publications; (5) distribution according to journals; and (6) comparison of study results on precision radiotherapy for brain tumors. RESULTS: The stereotactic radiotherapy, intensity-modulated radiotherapy, and imaging-guided radiotherapy are three major methods of precision radiotherapy for brain tumors. There were 260 research articles addressing precision radiotherapy for brain tumors found within the Web of Science. The USA published the most papers on precision radiotherapy for brain tumors, followed by Germany and France. European Synchrotron Radiation Facility, German Cancer Research Center and Heidelberg University were the most prolific research institutes for publications on precision radiotherapy for brain tumors. Among the top 13 research institutes publishing in this field, seven

  3. Prognostic significance of nodal involvement region in clinical stage IIIc breast cancer patients who received primary systemic treatment, surgery, and radiotherapy.

    PubMed

    Noh, Jae Myoung; Kim, Kyung Hwan; Park, Won; Suh, Chang Ok; Huh, Seung Jae; Choi, Doo Ho; Keum, Ki Chang; Kim, Yong Bae

    2015-10-01

    To evaluate the prognostic influence of involvement of both internal mammary nodes (IMNs) and supraclavicular nodes (SCNs) in clinical stage IIIc breast cancer patients who underwent primary systemic treatment, surgery, and radiotherapy (RT). Between 2001 and 2009, 110 breast cancer patients with IMN or SCN involvement were treated with primary systemic treatment followed by surgery and RT. The median age was 50 years. Clinical N-stage was cN3b and cN3c in 29 (26.4%) and 81 (73.6%) patients, respectively. Among the 81 patients with cN3c disease, 18 patients had both IMN and SCN involvement. Primary systemic treatment regimen was most commonly doxorubicin plus docetaxel (54.5%) or cyclophosphamide (20.0%). Mastectomy was performed in 71 (64.5%) patients. The RT dose delivered to the chest wall or whole breast was 50-50.4 Gy in 25-28 fractions. IMN and SCN regions were irradiated in 77 (70.0%) and 107 (97.6%) patients, respectively. At a median follow-up of 57.4 months (range, 8.6-149.9 months), 44 patients (40.0%) developed disease recurrence. Among the 18 patients with both IMN and SCN involvement, 12 patients experienced disease recurrence and 11 of them had distant metastases. The 5-year disease-free survival (DFS) and overall survival (OS) of all patients were 60.2% and 75.5%, respectively. Decreased DFS and OS were observed in the 18 patients with both IMN and SCN involvement (5-year rates, 33.3% and 50.0%; P = 0.0051 and 0.0010, respectively). Involvement of both IMNs and SCNs was associated with worse survival outcomes in patients with clinical stage IIIc breast cancer. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Non-small cell lung cancer (NSCLC) and central nervous system (CNS) metastases: role of tyrosine kinase inhibitors (TKIs) and evidence in favor or against their use with concurrent cranial radiotherapy

    PubMed Central

    Economopoulou, Panagiota

    2016-01-01

    Central nervous system (CNS) metastases, including brain metastases (BM) and leptomeningeal metastases (LM) represent a frequent complication of non-small cell lung cancer (NSCLC). Patients with BM comprise a heterogeneous group, with a median survival that ranges from 3 to 14 months. However, in the majority of patients, the occurrence of CNS metastases is usually accompanied by severe morbidity and substantial deterioration in quality of life. Local therapies, such as whole brain radiotherapy (WBRT), stereotactic radiosurgery (SRS) or surgical resection, either alone or as part of a multimodality treatment are available treatment strategies for BM and the choice of therapy varies depending on patient group and prognosis. Meanwhile, introduction of tyrosine kinase inhibitors (TKIs) in clinical practice has led to individualization of therapy based upon the presence of the exact abnormality, resulting in a major therapeutic improvement in patients with NSCLC who harbor epidermal growth factor receptor (EGFR) activating mutations or anaplastic lymphoma kinase (ALK) gene rearrangements, respectively. Based on their clinical activity in systemic disease, such molecular agents could offer the promise of improved BM control without substantial toxicity; however, their role in combination with radiotherapy is controversial. In this review, we discuss the controversy regarding the use of TKIs in combination with radiotherapy and illustrate future perspectives in the treatment of BM in NSCLC. PMID:28149754

  5. Intensity-Modulated and 3D-Conformal Radiotherapy for Whole-Ventricular Irradiation as Compared With Conventional Whole-Brain Irradiation in the Management of Localized Central Nervous System Germ Cell Tumors

    SciTech Connect

    Chen, Michael Jenwei; Silva Santos, Adriana da; Sakuraba, Roberto Kenji; Lopes, Cleverson Perceu; Goncalves, Vinicius Demanboro; Weltman, Eduardo; Ferrigno, Robson; Cruz, Jose Carlos

    2010-02-01

    Purpose: To compare the sparing potential of cerebral hemispheres with intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3D-CRT) for whole-ventricular irradiation (WVI) and conventional whole-brain irradiation (WBI) in the management of localized central nervous system germ cell tumors (CNSGCTs). Methods and Materials: Ten cases of patients with localized CNSGCTs and submitted to WVI by use of IMRT with or without a 'boost' to the primary lesion were selected. For comparison purposes, similar treatment plans were produced by use of 3D-CRT (WVI with or without boost) and WBI (opposed lateral fields with or without boost), and cerebral hemisphere sparing was evaluated at dose levels ranging from 2 Gy to 40 Gy. Results: The median prescription dose for WVI was 30.6 Gy (range, 25.2-37.5 Gy), and that for the boost was 16.5 Gy (range, 0-23.4 Gy). Mean irradiated cerebral hemisphere volumes were lower for WVI with IMRT than for 3D-CRT and were lower for WVI with 3D-CRT than for WBI. Intensity-modulated radiotherapy was associated with the lowest irradiated volumes, with reductions of 7.5%, 12.2%, and 9.0% at dose levels of 20, 30, and 40 Gy, respectively, compared with 3D-CRT. Intensity-modulated radiotherapy provided statistically significant reductions of median irradiated volumes at all dose levels (p = 0.002 or less). However, estimated radiation doses to peripheral areas of the body were 1.9 times higher with IMRT than with 3D-CRT. Conclusions: Although IMRT is associated with increased radiation doses to peripheral areas of the body, its use can spare a significant amount of normal central nervous system tissue compared with 3D-CRT or WBI in the setting of CNSGCT treatment.

  6. Accuracy Verification of Respiratory-gated Radiotherapy that Combines the Respiration-Monitoring Device and Respiratory-gated System.

    PubMed

    Shintani, Naoya; Monzen, Hajime; Tamura, Masaya; Asai, Yoshiyuki; Shimomura, Kouhei; Matsumoto, Kenji; Okumura, Masahiko; Nishimura, Yasumasa

    The purpose of this study is to evaluate the mechanical accuracy of a respiratory-gated radiation system that combines the Linear Indicator-equipped Abches respiration-monitoring device and the Varian Real-time Position Management system (LI-RPM system). This combined configuration, implemented for the first time in Japan, was compared with the stand-alone Varian RPM system (RPM system). The delay times, dose profiles, and output waveforms of the LI-RPM and RPM systems were evaluated using a self-produced dynamic phantom. The delay times for the LI-RPM and RPM systems were both 0.1 s for 4 s and 8 s test periods. The corresponding output waveform correlation factors (R(2)) for the 4 s and 8 s test periods were 0.9981 and 0.9975, respectively. No difference was observed in the dose profiles of the two systems. Thus, the present results indicate that the proposed LI-RPM combined respiratory-gated radiation system has similar properties to the RPM system. However, it offers several advantages in terms of its versatility, including its alignment assistance capabilities for non-coplanar treatments.

  7. [Radiotherapy for Graves' ophthalmopathy].

    PubMed

    Kuhnt, T; Müller, A C; Janich, M; Gerlach, R; Hädecke, J; Duncker, G I W; Dunst, J

    2004-11-01

    Graves' ophthalmopathy (GO) is the most frequent extrathyroidal manifestation of Graves' disease, an autoimmune disorder of the thyroid, whereas the precise pathogenesis still remains unclear. In Hashimoto's thyroiditis the occurrence of proptosis is an extremely rare event. The therapy for middle and severe courses of GO shows in partly disappointing results, although several therapy modalities are possible (glucocorticoid therapy, radiotherapy, antithyroid drug treatment, surgery). All these therapies lead in only 40 - 70 % to an improvement of the pathogenic symptoms. An intensive interdisciplinary cooperation is necessary to satisfy the requirements for the treatment of Graves' ophthalmopathy. As a consequence of the very different results of the few of clinical studies that were accomplished with reference to this topic, treatment by radiotherapy in the management of the disease is presently controversially discussed. In the German-speaking countries the radiotherapy is, however, firmly established as a therapy option in the treatment of the moderate disease classes (class 2-5 according to NO SPECS), especially if diplopia is present. This article describes the sequences, dosages and fractionation schemes as well as the risks and side effects of the radiotherapy. Altogether, radiotherapy is assessed as an effective and sure method. The administration of glucocorticoids can take place before the beginning of or during the radiotherapy. For the success of treatment the correct selection of patients who may possibly profit from a radiotherapy is absolutely essential. By realising that GO proceeds normally over a period of 2-5 years, which is followed by a period of fibrotic alteration, the application of the radiotherapy in the early, active phase is indispensable. A precise explanation for the effects of radiotherapy in treatment of the GO does not exist at present. The determination of the most effective irradiation doses was made from retrospectively evaluated

  8. Quantitative evaluation of patient setup uncertainty of stereotactic radiotherapy with the frameless 6D ExacTrac system using statistical modeling.

    PubMed

    Keeling, Vance; Hossain, Sabbir; Jin, Hosang; Algan, Ozer; Ahmad, Salahuddin; Ali, Imad

    2016-05-08

    The purpose of this study is to evaluate patient setup accuracy and quantify indi-vidual and cumulative positioning uncertainties associated with different hardware and software components of the stereotactic radiotherapy (SRS/SRT) with the frameless 6D ExacTrac system. A statistical model is used to evaluate positioning uncertainties of the different components of SRS/SRT treatment with the Brainlab 6D ExacTrac system using the positioning shifts of 35 patients having cranial lesions. All these patients are immobilized with rigid head-and-neck masks, simu-lated with Brainlab localizer and planned with iPlan treatment planning system. Stereoscopic X-ray images (XC) are acquired and registered to corresponding digitally reconstructed radiographs using bony-anatomy matching to calculate 6D translational and rotational shifts. When the shifts are within tolerance (0.7 mm and 1°), treatment is initiated. Otherwise corrections are applied and additional X-rays (XV) are acquired to verify that patient position is within tolerance. The uncertain-ties from the mask, localizer, IR -frame, X-ray imaging, MV, and kV isocentricity are quantified individually. Mask uncertainty (translational: lateral, longitudinal, vertical; rotational: pitch, roll, yaw) is the largest and varies with patients in the range (-2.07-3.71 mm, -5.82-5.62 mm, -5.84-3.61 mm; -2.10-2.40°, -2.23-2.60°, and -2.7-3.00°) obtained from mean of XC shifts for each patient. Setup uncer-tainty in IR positioning (0.88, 2.12, 1.40 mm, and 0.64°, 0.83°, 0.96°) is extracted from standard deviation of XC. Systematic uncertainties of the frame (0.18, 0.25, -1.27mm, -0.32°, 0.18°, and 0.47°) and localizer (-0.03, -0.01, 0.03mm, and -0.03°, 0.00°, -0.01°) are extracted from means of all XV setups and mean of all XC distributions, respectively. Uncertainties in isocentricity of the MV radiotherapy machine are (0.27, 0.24, 0.34 mm) and kV imager (0.15, -0.4, 0.21 mm). A statisti-cal model is developed to

  9. Quantitative evaluation of patient setup uncertainty of stereotactic radiotherapy with the frameless 6D ExacTrac system using statistical modeling.

    PubMed

    Keeling, Vance; Hossain, Sabbir; Jin, Hosang; Algan, Ozer; Ahmad, Salahuddin; Ali, Imad

    2016-05-01

    The purpose of this study is to evaluate patient setup accuracy and quantify individual and cumulative positioning uncertainties associated with different hardware and software components of the stereotactic radiotherapy (SRS/SRT) with the frameless 6D ExacTrac system. A statistical model is used to evaluate positioning uncertainties of the different components of SRS/SRT treatment with the Brainlab 6D ExacTrac system using the positioning shifts of 35 patients having cranial lesions. All these patients are immobilized with rigid head-and-neck masks, simulated with Brainlab localizer and planned with iPlan treatment planning system. Stereoscopic X-ray images (XC) are acquired and registered to corresponding digitally reconstructed radiographs using bony-anatomy matching to calculate 6D translational and rotational shifts. When the shifts are within tolerance (0.7 mm and 1°), treatment is initiated. Otherwise corrections are applied and additional X-rays (XV) are acquired to verify that patient position is within tolerance. The uncertainties from the mask, localizer, IR -frame, X-ray imaging, MV, and kV isocentricity are quantified individually. Mask uncertainty (translational: lateral, longitudinal, vertical; rotational: pitch, roll, yaw) is the largest and varies with patients in the range (-2.07-3.71mm,-5.82-5.62mm,-5.84-3.61mm;-2.10-2.40∘,-2.23-2.60∘,and-2.7-3.00∘) obtained from mean of XC shifts for each patient. Setup uncertainty in IR positioning (0.88, 2.12, 1.40 mm, and 0.64°, 0.83°, 0.96°) is extracted from standard deviation of XC. Systematic uncertainties of the frame (0.18, 0.25, -1.27mm, -0.32∘, 0.18°, and 0.47°) and localizer (-0.03, -0.01, 0.03 mm, and -0.03∘, 0.00°, -0.01∘) are extracted from means of all XV setups and mean of all XC distributions, respectively. Uncertainties in isocentricity of the MV radiotherapy machine are (0.27, 0.24, 0.34 mm) and kV imager (0.15, -0.4, 0.21 mm). A statistical model is developed to evaluate

  10. SU-E-T-659: Quantitative Evaluation of Patient Setup Accuracy of Stereotactic Radiotherapy with the Frameless 6D-ExacTrac System Using Statistical Modeling

    SciTech Connect

    Keeling, V; Jin, H; Hossain, S; Algan, O; Ahmad, S; Ali, I

    2015-06-15

    Purpose: To evaluate patient setup accuracy and quantify individual and cumulative positioning uncertainties associated with different hardware and software components of the stereotactic radiotherapy (SRS/SRT) with the frameless-6D-ExacTrac system. Methods: A statistical model was used to evaluate positioning uncertainties of the different components of SRS/SRT treatment with the BrainLAB 6D-ExacTrac system using the positioning shifts of 35 patients having cranial lesions (49 total lesions treated in 1, 3, 5 fractions). All these patients were immobilized with rigid head-and-neck masks, simulated with BrainLAB-localizer and planned with iPlan treatment planning system. Infrared imaging (IR) was used initially to setup patients. Then, stereoscopic x-ray images (XC) were acquired and registered to corresponding digitally-reconstructed-radiographs using bony-anatomy matching to calculate 6D-translational and rotational shifts. When the shifts were within tolerance (0.7mm and 1°), treatment was initiated. Otherwise corrections were applied and additional x-rays were acquired (XV) to verify that patient position was within tolerance. Results: The uncertainties from the mask, localizer, IR-frame, x-ray imaging, MV and kV isocentricity were quantified individually. Mask uncertainty (Translational: Lateral, Longitudinal, Vertical; Rotational: Pitch, Roll, Yaw) was the largest and varied with patients in the range (−1.05−1.50mm, −5.06–3.57mm, −5.51−3.49mm; −1.40−2.40°, −1.24−1.74°, and −2.43−1.90°) obtained from mean of XC shifts for each patient. Setup uncertainty in IR positioning (0.88,2.12,1.40mm, and 0.64,0.83,0.96°) was extracted from standard-deviation of XC. Systematic uncertainties of the localizer (−0.03,−0.01,0.03mm, and −0.03,0.00,−0.01°) and frame (0.18,0.25,−1.27mm,−0.32,0.18, and 0.47°) were extracted from means of all XV setups and mean of all XC distributions, respectively. Uncertainties in isocentricity of the

  11. Stereotactic body radiotherapy for oligometastases.

    PubMed

    Tree, Alison C; Khoo, Vincent S; Eeles, Rosalind A; Ahmed, Merina; Dearnaley, David P; Hawkins, Maria A; Huddart, Robert A; Nutting, Christopher M; Ostler, Peter J; van As, Nicholas J

    2013-01-01

    The management of metastatic solid tumours has historically focused on systemic treatment given with palliative intent. However, radical surgical treatment of oligometastases is now common practice in some settings. The development of stereotactic body radiotherapy (SBRT), building on improvements in delivery achieved by intensity-modulated and image-guided radiotherapy, now allows delivery of ablative doses of radiation to extracranial sites. Many non-randomised studies have shown that SBRT for oligometastases is safe and effective, with local control rates of about 80%. Importantly, these studies also suggest that the natural history of the disease is changing, with 2-5 year progression-free survival of about 20%. Although complete cure might be possible in a few patients with oligometastases, the aim of SBRT in this setting is to achieve local control and delay progression, and thereby also postpone the need for further treatment. We review published work showing that SBRT offers durable local control and the potential for progression-free survival in non-liver, non-lung oligometastatic disease at a range of sites. However, to test whether SBRT really does improve progression-free survival, randomised trials will be essential. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. SU-E-J-47: Development of a High-Precision, Image-Guided Radiotherapy, Multi- Purpose Radiation Isocenter Quality-Assurance Calibration and Checking System

    SciTech Connect

    Liu, C; Yan, G; Helmig, R; Lebron, S; Kahler, D

    2014-06-01

    Purpose: To develop a system that can define the radiation isocenter and correlate this information with couch coordinates, laser alignment, optical distance indicator (ODI) settings, optical tracking system (OTS) calibrations, and mechanical isocenter walkout. Methods: Our team developed a multi-adapter, multi-purpose quality assurance (QA) and calibration device that uses an electronic portal imaging device (EPID) and in-house image-processing software to define the radiation isocenter, thereby allowing linear accelerator (Linac) components to be verified and calibrated. Motivated by the concept that each Linac component related to patient setup for image-guided radiotherapy based on cone-beam CT should be calibrated with respect to the radiation isocenter, we designed multiple concentric adapters of various materials and shapes to meet the needs of MV and KV radiation isocenter definition, laser alignment, and OTS calibration. The phantom's ability to accurately define the radiation isocenter was validated on 4 Elekta Linacs using a commercial ball bearing (BB) phantom as a reference. Radiation isocenter walkout and the accuracy of couch coordinates, ODI, and OTS were then quantified with the device. Results: The device was able to define the radiation isocenter within 0.3 mm. Radiation isocenter walkout was within ±1 mm at 4 cardinal angles. By switching adapters, we identified that the accuracy of the couch position digital readout, ODI, OTS, and mechanical isocenter walkout was within sub-mm. Conclusion: This multi-adapter, multi-purpose isocenter phantom can be used to accurately define the radiation isocenter and represents a potential paradigm shift in Linac QA. Moreover, multiple concentric adapters allowed for sub-mm accuracy for the other relevant components. This intuitive and user-friendly design is currently patent pending.

  13. Effects of treatment intensification on acute local toxicity during radiotherapy for head and neck cancer: prospective observational study validating CTCAE, version 3.0, scoring system.

    PubMed

    Palazzi, Mauro; Tomatis, Stefano; Orlandi, Ester; Guzzo, Marco; Sangalli, Claudia; Potepan, Paolo; Fantini, Simona; Bergamini, Cristiana; Gavazzi, Cecilia; Licitra, Lisa; Scaramellini, Gabriele; Cantu', Giulio; Olmi, Patrizia

    2008-02-01

    To quantify the incidence and severity of acute local toxicity in head and neck cancer patients treated with radiotherapy (RT), with or without chemotherapy (CHT), using the Common Terminology Criteria for Adverse Events, version 3.0 (CTCAE v3.0), scoring system. Between 2004 and 2006, 149 patients with head and neck cancer treated with RT at our center were prospectively evaluated for local toxicity during treatment. On a weekly basis, patients were monitored and eight toxicity items were recorded according to the CTCAE v3.0 scoring system. Of the 149 patients, 48 (32%) were treated with RT alone (conventional fractionation), 82 (55%) with concomitant CHT and conventional fractionation RT, and 20 (13%) with accelerated-fractionation RT and CHT. Severe (Grade 3-4) adverse events were recorded in 28% (mucositis), 33% (dysphagia), 40% (pain), and 12% (skin) of patients. Multivariate analysis showed CHT to be the most relevant factor independently predicting for worse toxicity (mucositis, dysphagia, weight loss, salivary changes). In contrast, previous surgery, RT acceleration and older age, female gender, and younger age, respectively, predicted for a worse outcome of mucositis, weight loss, pain, and dermatitis. The T-score method confirmed that conventional RT alone is in the "low-burden" class (T-score = 0.6) and suggests that concurrent CHT and conventional fractionation RT is in the "high-burden" class (T-score = 1.15). Combined CHT and accelerated-fractionation RT had the highest T-score at 1.9. The CTCAE v3.0 proved to be a reliable tool to quantify acute toxicity in head and neck cancer patients treated with various treatment intensities. The effect of CHT and RT acceleration on the acute toxicity burden was clinically relevant.

  14. Effects of Treatment Intensification on Acute Local Toxicity During Radiotherapy for Head and Neck Cancer: Prospective Observational Study Validating CTCAE, Version 3.0, Scoring System

    SciTech Connect

    Palazzi, Mauro Tomatis, Stefano; Orlandi, Ester; Guzzo, Marco; Sangalli, Claudia; Potepan, Paolo; Fantini, Simona; Bergamini, Cristiana; Gavazzi, Cecilia; Licitra, Lisa; Scaramellini, Gabriele; Cantu', Giulio; Olmi, Patrizia

    2008-02-01

    Purpose: To quantify the incidence and severity of acute local toxicity in head and neck cancer patients treated with radiotherapy (RT), with or without chemotherapy (CHT), using the Common Terminology Criteria for Adverse Events, version 3.0 (CTCAE v3.0), scoring system. Methods and Materials: Between 2004 and 2006, 149 patients with head and neck cancer treated with RT at our center were prospectively evaluated for local toxicity during treatment. On a weekly basis, patients were monitored and eight toxicity items were recorded according to the CTCAE v3.0 scoring system. Of the 149 patients, 48 (32%) were treated with RT alone (conventional fractionation), 82 (55%) with concomitant CHT and conventional fractionation RT, and 20 (13%) with accelerated-fractionation RT and CHT. Results: Severe (Grade 3-4) adverse events were recorded in 28% (mucositis), 33% (dysphagia), 40% (pain), and 12% (skin) of patients. Multivariate analysis showed CHT to be the most relevant factor independently predicting for worse toxicity (mucositis, dysphagia, weight loss, salivary changes). In contrast, previous surgery, RT acceleration and older age, female gender, and younger age, respectively, predicted for a worse outcome of mucositis, weight loss, pain, and dermatitis. The T-score method confirmed that conventional RT alone is in the 'low-burden' class (T-score = 0.6) and suggests that concurrent CHT and conventional fractionation RT is in the 'high-burden' class (T-score = 1.15). Combined CHT and accelerated-fractionation RT had the highest T-score at 1.9. Conclusions: The CTCAE v3.0 proved to be a reliable tool to quantify acute toxicity in head and neck cancer patients treated with various treatment intensities. The effect of CHT and RT acceleration on the acute toxicity burden was clinically relevant.

  15. Three-dimensional intrafractional motion of breast during tangential breast irradiation monitored with high-sampling frequency using a real-time tumor-tracking radiotherapy system.

    PubMed

    Kinoshita, Rumiko; Shimizu, Shinichi; Taguchi, Hiroshi; Katoh, Norio; Fujino, Masaharu; Onimaru, Rikiya; Aoyama, Hidefumi; Katoh, Fumi; Omatsu, Tokuhiko; Ishikawa, Masayori; Shirato, Hiroki

    2008-03-01

    To evaluate the three-dimensional intrafraction motion of the breast during tangential breast irradiation using a real-time tracking radiotherapy (RT) system with a high-sampling frequency. A total of 17 patients with breast cancer who had received breast conservation RT were included in this study. A 2.0-mm gold marker was placed on the skin near the nipple of the breast for RT. A fluoroscopic real-time tumor-tracking RT system was used to monitor the marker. The range of motion of each patient was calculated in three directions. The mean +/- standard deviation of the range of respiratory motion was 1.0 +/- 0.6 mm (median, 0.9; 95% confidence interval [CI] of the marker position, 0.4-2.6), 1.3 +/- 0.5 mm (median, 1.1; 95% CI, 0.5-2.5), and 2.6 +/- 1.4 (median, 2.3; 95% CI, 1.0-6.9) for the right-left, craniocaudal, and anteroposterior direction, respectively. No correlation was found between the range of motion and the body mass index or respiratory function. The mean +/- standard deviation of the absolute value of the baseline shift in the right-left, craniocaudal, and anteroposterior direction was 0.2 +/- 0.2 mm (range, 0.0-0.8 mm), 0.3 +/- 0.2 mm (range, 0.0-0.7 mm), and 0.8 +/- 0.7 mm (range, 0.1-1.8 mm), respectively. Both the range of motion and the baseline shift were within a few millimeters in each direction. As long as the conventional wedge-pair technique and the proper immobilization are used, the intrafraction three-dimensional change in the breast surface did not much influence the dose distribution.

  16. ENT COBRA (Consortium for Brachytherapy Data Analysis): interdisciplinary standardized data collection system for head and neck patients treated with interventional radiotherapy (brachytherapy).

    PubMed

    Tagliaferri, Luca; Kovács, György; Autorino, Rosa; Budrukkar, Ashwini; Guinot, Jose Luis; Hildebrand, Guido; Johansson, Bengt; Monge, Rafael Martìnez; Meyer, Jens E; Niehoff, Peter; Rovirosa, Angeles; Takàcsi-Nagy, Zoltàn; Dinapoli, Nicola; Lanzotti, Vito; Damiani, Andrea; Soror, Tamer; Valentini, Vincenzo

    2016-08-01

    Aim of the COBRA (Consortium for Brachytherapy Data Analysis) project is to create a multicenter group (consortium) and a web-based system for standardized data collection. GEC-ESTRO (Groupe Européen de Curiethérapie - European Society for Radiotherapy & Oncology) Head and Neck (H&N) Working Group participated in the project and in the implementation of the consortium agreement, the ontology (data-set) and the necessary COBRA software services as well as the peer reviewing of the general anatomic site-specific COBRA protocol. The ontology was defined by a multicenter task-group. Eleven centers from 6 countries signed an agreement and the consortium approved the ontology. We identified 3 tiers for the data set: Registry (epidemiology analysis), Procedures (prediction models and DSS), and Research (radiomics). The COBRA-Storage System (C-SS) is not time-consuming as, thanks to the use of "brokers", data can be extracted directly from the single center's storage systems through a connection with "structured query language database" (SQL-DB), Microsoft Access(®), FileMaker Pro(®), or Microsoft Excel(®). The system is also structured to perform automatic archiving directly from the treatment planning system or afterloading machine. The architecture is based on the concept of "on-purpose data projection". The C-SS architecture is privacy protecting because it will never make visible data that could identify an individual patient. This C-SS can also benefit from the so called "distributed learning" approaches, in which data never leave the collecting institution, while learning algorithms and proposed predictive models are commonly shared. Setting up a consortium is a feasible and practicable tool in the creation of an international and multi-system data sharing system. COBRA C-SS seems to be well accepted by all involved parties, primarily because it does not influence the center's own data storing technologies, procedures, and habits. Furthermore, the method

  17. ENT COBRA (Consortium for Brachytherapy Data Analysis): interdisciplinary standardized data collection system for head and neck patients treated with interventional radiotherapy (brachytherapy)

    PubMed Central

    Tagliaferri, Luca; Kovács, György; Budrukkar, Ashwini; Guinot, Jose Luis; Hildebrand, Guido; Johansson, Bengt; Monge, Rafael Martìnez; Meyer, Jens E.; Niehoff, Peter; Rovirosa, Angeles; Takàcsi-Nagy, Zoltàn; Dinapoli, Nicola; Lanzotti, Vito; Damiani, Andrea; Soror, Tamer; Valentini, Vincenzo

    2016-01-01

    Purpose Aim of the COBRA (Consortium for Brachytherapy Data Analysis) project is to create a multicenter group (consortium) and a web-based system for standardized data collection. Material and methods GEC-ESTRO (Groupe Européen de Curiethérapie – European Society for Radiotherapy & Oncology) Head and Neck (H&N) Working Group participated in the project and in the implementation of the consortium agreement, the ontology (data-set) and the necessary COBRA software services as well as the peer reviewing of the general anatomic site-specific COBRA protocol. The ontology was defined by a multicenter task-group. Results Eleven centers from 6 countries signed an agreement and the consortium approved the ontology. We identified 3 tiers for the data set: Registry (epidemiology analysis), Procedures (prediction models and DSS), and Research (radiomics). The COBRA-Storage System (C-SS) is not time-consuming as, thanks to the use of “brokers”, data can be extracted directly from the single center's storage systems through a connection with “structured query language database” (SQL-DB), Microsoft Access®, FileMaker Pro®, or Microsoft Excel®. The system is also structured to perform automatic archiving directly from the treatment planning system or afterloading machine. The architecture is based on the concept of “on-purpose data projection”. The C-SS architecture is privacy protecting because it will never make visible data that could identify an individual patient. This C-SS can also benefit from the so called “distributed learning” approaches, in which data never leave the collecting institution, while learning algorithms and proposed predictive models are commonly shared. Conclusions Setting up a consortium is a feasible and practicable tool in the creation of an international and multi-system data sharing system. COBRA C-SS seems to be well accepted by all involved parties, primarily because it does not influence the center's own data storing

  18. SU-E-J-12: An Image-Guided Soft Robotic Patient Positioning System for Maskless Head-And-Neck Cancer Radiotherapy: A Proof-Of-Concept Study

    SciTech Connect

    Ogunmolu, O; Gans, N; Jiang, S; Gu, X

    2015-06-15

    Purpose: We propose a surface-image-guided soft robotic patient positioning system for maskless head-and-neck radiotherapy. The ultimate goal of this project is to utilize a soft robot to realize non-rigid patient positioning and real-time motion compensation. In this proof-of-concept study, we design a position-based visual servoing control system for an air-bladder-based soft robot and investigate its performance in controlling the flexion/extension cranial motion on a mannequin head phantom. Methods: The current system consists of Microsoft Kinect depth camera, an inflatable air bladder (IAB), pressured air source, pneumatic valve actuators, custom-built current regulators, and a National Instruments myRIO microcontroller. The performance of the designed system was evaluated on a mannequin head, with a ball joint fixed below its neck to simulate torso-induced head motion along flexion/extension direction. The IAB is placed beneath the mannequin head. The Kinect camera captures images of the mannequin head, extracts the face, and measures the position of the head relative to the camera. This distance is sent to the myRIO, which runs control algorithms and sends actuation commands to the valves, inflating and deflating the IAB to induce head motion. Results: For a step input, i.e. regulation of the head to a constant displacement, the maximum error was a 6% overshoot, which the system then reduces to 0% steady-state error. In this initial investigation, the settling time to reach the regulated position was approximately 8 seconds, with 2 seconds of delay between the command start of motion due to capacitance of the pneumatics, for a total of 10 seconds to regulate the error. Conclusion: The surface image-guided soft robotic patient positioning system can achieve accurate mannequin head flexion/extension motion. Given this promising initial Result, the extension of the current one-dimensional soft robot control to multiple IABs for non-rigid positioning control

  19. Virtual reality training for radiotherapy becomes a reality.

    PubMed

    Phillips, R; Ward, J W; Page, L; Grau, C; Bojen, A; Hall, J; Nielsen, K; Nordentoft, V; Beavis, A W

    2008-01-01

    A report in 2007 to the UK Government identified a crisis in England for training staff and students for the radiotherapy treatment of cancer. The Hull authors have developed an immersive life size virtual environment of a radiotherapy treatment room, known as VERT, to address this problem. VERT provides the trainee with models, simulation, enhanced visualization and training aids for treatment of virtual patients in a virtual treatment room. In 2007 immersive VERT systems for radiotherapy training were established for training purposes at the University Aarhus Hospital (Denmark) and the Birmingham City University (UK). This paper reports on early evaluations of VERT by these two institutions.

  20. Radiotherapy for bone pain.

    PubMed Central

    Needham, P R; Mithal, N P; Hoskin, P J

    1994-01-01

    Painful bone metastases are a common problem for cancer patients. Although current evidence supports the use of a single fraction of radiotherapy as the treatment of choice, many radiotherapists, for a variety of reasons, continue to use fractionated regimens. Over one six month period 105 patients received external beam irradiation for painful bone metastases at the Royal London Hospital (RLH). Thirty-one per cent of the patients were aged 70 or over. The treatment of 97 of these patients was assessed. They had a total of 280 sites treated over the course of their disease. Fifty-nine per cent of sites treated received a fractionated course of radiotherapy. Site significantly influenced fractionation. Overall response rates of 82% were achieved. Fractionation did not appear to influence this. Ten patients received large field irradiation. Fifteen patients had five or more sites irradiated, of whom only one received hemibody irradiation. PMID:7523672

  1. Melanoma: Last call for radiotherapy.

    PubMed

    Espenel, Sophie; Vallard, Alexis; Rancoule, Chloé; Garcia, Max-Adrien; Guy, Jean-Baptiste; Chargari, Cyrus; Deutsch, Eric; Magné, Nicolas

    2017-02-01

    Melanoma is traditionally considered to be a radioresistant tumor. However, radiotherapy and immunotherapy latest developments might upset this radiobiological dogma. Stereotactic radiotherapy allows high dose per fraction delivery, with high dose rate. More DNA lethal damages, less sublethal damages reparation, endothelial cell apoptosis, and finally clonogenic cell dysfunction are produced, resulting in improved local control. Radiotherapy can also enhance immune responses, inducing neoantigens formation, tumor antigen presentation, and cytokines release. A synergic effect of radiotherapy with immunotherapy is expected, and might lead to abscopal effects. If hadrontherapy biological properties seem able to suppress hypoxia-induced radioresistance and increase biological efficacy, ballistic advantages over photon radiations might also improve radiotherapy outcomes on usually poor prognosis locations. The present review addresses biological and clinical effects of high fraction dose, bystander effect, abscopal effect, and hadrontherapy features in melanoma. Clinical trials results are warranted to establish indications of innovative radiotherapy in melanoma.

  2. Accident prevention in radiotherapy

    PubMed Central

    Holmberg, O

    2007-01-01

    In order to prevent accidents in radiotherapy, it is important to learn from accidents that have occurred previously. Lessons learned from a number of accidents are summarised and underlying patterns are looked for in this paper. Accidents can be prevented by applying several safety layers of preventive actions. Categories of these preventive actions are discussed together with specific actions belonging to each category of safety layer. PMID:21614274

  3. [Radiotherapy of bladder cancer].

    PubMed

    Riou, O; Chauvet, B; Lagrange, J-L; Martin, P; Llacer Moscardo, C; Charissoux, M; Lauche, O; Aillères, N; Fenoglietto, P; Azria, D

    2016-09-01

    Surgery (radical cystectomy) is the standard treatment of muscle-invasive bladder cancer. Radiochemotherapy has risen as an alternative treatment option to surgery as part as organ-sparing combined modality treatment or for patients unfit for surgery. Radiochemotherapy achieves 5-year bladder intact survival of 40 to 65% and 5-year overall survival of 40 to 50% with excellent quality of life. This article introduces the French recommendations for radiotherapy of bladder cancer: indications, exams, technique, dosimetry, delivery and image guidance.

  4. Imaging in radiotherapy.

    PubMed

    Van den Berge, D L; De Ridder, M; Storme, G A

    2000-10-01

    Radiotherapy, more then any other treatment modality, relies heavily and often exclusively on medical imaging to determine the extent of disease and the spatial relation between target region and neighbouring healthy tissues. Radically new approaches to radiation delivery are inspired on CT scanning and treat patients in a slice-by-slice fashion using intensity modulated megavoltage fan beams. For quality assurance of complex 3-D dose distributions, MR based 3-D verificative dosimetry on irradiated phantoms has been described. As treatment delivery becomes increasingly refined, the need for accurate target definition increases as well and sophisticated imaging tools like image fusion and 3-D reconstruction are routinely used for treatment planning. While in the past patients were positioned on the treatment machines based exclusively on surface topography and the well-known skin marks, such approach is no longer sufficient for high-accuracy radiotherapy and special imaging tools like on-line portal imaging are used to verify and correct target positioning. Much of these applications rely on digital image processing, transmission and storage, and the development of standards, like DICOM and PACS have greatly contributed to these applications. Digital imaging plays an increasing role in many areas in radiotherapy and has been fundamental in new developments that have demonstrated impact on patient care.

  5. Poster — Thur Eve — 28: Enabling trajectory-based radiotherapy on a TrueBeam accelerator with the Eclipse treatment planning system

    SciTech Connect

    Mullins, J; Asiev, K; DeBlois, F; Morcos, M; Seuntjens, J; Syme, A

    2014-08-15

    The TrueBeam linear accelerator platform has a developer's mode which permits the user dynamic control over many of the machine's mechanical and radiation systems. Using this research tool, synchronous couch and gantry motion can be programmed to simulate isocentric treatment with a shortened SAD, with benefits such as smaller projected MLC leaf widths and an increased dose rate. In this work, water tank measurements were used to commission a virtual linear accelerator with an 85 cm SAD in Eclipse, from which several arc-based radiotherapy treatments were generated, including an inverse optimized VMAT delivery. For each plan, the pertinent treatment delivery information was extracted from control points specified in the Eclipse-exported DICOM files using the pydicom package in Python, allowing construction of an XML control file. The dimensions of the jaws and MLC positions, defined for an 85 cm SAD in Eclipse, were scaled for delivery on a conventional SAD linear accelerator, and translational couch motion was added as a function of gantry angle to simulate delivery at 85 cm SAD. Ionization chamber and Gafchromic film measurements were used to compare the radiation delivery to dose calculations in Eclipse. With the exception of the VMAT delivery, ionization chamber measurements agreed within 3.3% of the Eclipse calculations. For the VMAT delivery, the ionization chamber was located in an inhomogeneous region, but gamma evaluation of the Gafchromic film plane resulted in a 94.5% passing rate using criteria of 3 mm/3%. The results indicate that Eclipse calculation infrastructure can be used.

  6. CXCR4 and CXCL12 Expression in Rectal Tumors of Stage IV Patients Before and After Local Radiotherapy and Systemic Neoadjuvant Treatment.

    PubMed

    Tamas, Karin; Domanska, Urszula M; van Dijk, Tonnis H; Timmer-Bosscha, Hetty; Havenga, Klaas; Karrenbeld, Arend; Sluiter, Wim J; Beukema, Jannet C; van Vugt, Marcel A T M; de Vries, Elisabeth G E; Hospers, Geke A P; Walenkamp, Annemiek M E

    2015-01-01

    Metastatic rectal cancer patients could benefit from novel therapeutic approaches. The signaling network formed by chemokines and their receptors can promote metastasis and resistance to current anticancer treatments. This study assessed the expression of chemokine receptor 4 (CXCR4) and its ligand CXCL12 immuhistochemically in stage IV rectal tumors. Paraffin-embedded primary tumor collected before and after local radiotherapy and systemic treatment with bevacizumab, oxaliplatin and capecitabine was analyzed. Receptor and ligand expression was assessed in the cytoplasm and nucleus of tumor, stromal and normal rectal crypt cells. Baseline expression of CXCR4 and CXCL12 was correlated with patients' pathologic response to treatment. At diagnosis (n=46), 89% of the rectal tumors expressed cytoplasmic CXCR4 and 81% CXCL12. Nuclear CXCR4 expression in tumor cells was present in 30% and nuclear CXCL12 expression in 35% of the tumors. After radiochemotherapy and administration of bevacizumab, nuclear CXCL12 expression was observed in 79% of residual tumors, as compared to 31% of the paired tumor samples expressing nuclear CXCL12 before treatment (P=0.001). There were no differences in CXCR4 or CXCL12 expression at baseline between the patients who had (n=9) and did not have (n=30) a pathologic complete response. Our results show that CXCR4 and CXCL12 are extensively expressed in primary rectal tumors of patients presenting with metastatic disease, while radiochemotherapy and bevacizumab further upregulate CXCL12 expression. These data indicate the importance of the CXCR4/CXCL12 axis in rectal tumor biology, and may suggest the CXCR4/CXCL12 receptor-ligand pair as a potential therapeutic target in metastatic rectal cancer.

  7. Consolidation Radiotherapy in Primary Central Nervous System Lymphomas: Impact on Outcome of Different Fields and Doses in Patients in Complete Remission After Upfront Chemotherapy

    SciTech Connect

    Ferreri, Andres Jose Maria; Verona, Chiara; Politi, Letterio Salvatore; Chiara, Anna; Perna, Lucia; Villa, Eugenio; Reni, Michele

    2011-05-01

    Purpose: Avoidance radiotherapy or reduction of irradiation doses in patients with primary central nervous system lymphoma (PCNSL) in complete remission (CR) after high-dose methotrexate (HD-MTX)-based chemotherapy has been proposed to minimize the neurotoxicity risk. Nevertheless, no study has focused on the survival impact of radiation parameters, as far as we know, and the optimal radiation schedule remains to be defined. Methods and Materials: The impact on outcome and neurologic performance of different radiation fields and doses was assessed in 33 patients with PCNSL who achieved CR after MTX-containing chemotherapy and were referred to consolidation whole-brain irradiation (WBRT). Patterns of relapse were analyzed on computed tomography-guided treatment planning, and neurologic impairment was assessed by the Mini Mental Status Examination. Results: At a median follow-up of 50 months, 21 patients are relapse-free (5-year failure-free survival [FFS], 51%). WBRT doses {>=}40 Gy were not associated with improved disease control in comparison with a WBRT dose of 30 to 36 Gy (relapse rate, 46% vs. 30%; 5-year FFS, 51% vs. 50%; p = 0.26). Disease control was not significantly different between patients irradiated to the tumor bed with 45 to 54 Gy or with 36 to 44 Gy, with a 5-year FFS of 35% and 44% (p = 0.43), respectively. Twenty patients are alive (5-year overall survival, 54%); WB and tumor bed doses did not have an impact on survival. Impairment as assessed by the Mini Mental Status Examination was significantly more common in patients treated with a WBRT dose {>=}40 Gy. Conclusion: Consolidation with WBRT 36 Gy is advisable in patients with PCNSL in CR after HD-MTX-based chemotherapy. Higher doses do not change the outcome and could increase the risk of neurotoxicity.

  8. Renin-Angiotensin System Inhibitors Might Help to Reduce the Development of Symptomatic Radiation Pneumonitis After Stereotactic Body Radiotherapy for Lung Cancer.

    PubMed

    Bracci, Stefano; Valeriani, Maurizio; Agolli, Linda; De Sanctis, Vitaliana; Maurizi Enrici, Riccardo; Osti, Mattia F

    2016-05-01

    The purpose of the present study was to evaluate the role of renin-angiotensin system (RAS) inhibitors in preventing symptomatic radiation pneumonitis (RP) after stereotactic body radiotherapy (SBRT). The data from 158 patients with a solitary lung lesion treated with 1 to 3 fractions of SBRT from December 2008 to July 2014 were retrospectively analyzed. The incidence of RP was evaluated according to the Common Toxicity Criteria for Adverse Events, version 4. The use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) was analyzed to assess for possible correlations with the development of grade ≥ 2 RP. The patient and dosimetric variables were also assessed. After a median follow-up period of 13.8 months (range, 3.2-55.0 months), 22 patients had developed grade ≥ 2 RP. Patients with peripheral lesions, favorable dosimetric data, and ACEI and/or ARB use had a reduced risk of symptomatic RP. In unadjusted and adjusted multivariate analyses, ACEI and/or ARB intake and the dosimetric variables were statistically significant factors. In a secondary analysis, the use of ACEIs and ARBs among patients with a greater planning target volume and higher dosimetric values correlated with a reduced risk of symptomatic RP. The use of a RAS inhibitor was associated with a decreased incidence of symptomatic RP among patients undergoing SBRT for lung lesions. Patients with higher dosimetric values had a reduced risk of grade ≥ 2 RP with ACEI and ARB use. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Consolidation radiotherapy in primary central nervous system lymphomas: impact on outcome of different fields and doses in patients in complete remission after upfront chemotherapy.

    PubMed

    Ferreri, Andrés José María; Verona, Chiara; Politi, Letterio Salvatore; Chiara, Anna; Perna, Lucia; Villa, Eugenio; Reni, Michele

    2011-05-01

    Avoidance radiotherapy or reduction of irradiation doses in patients with primary central nervous system lymphoma (PCNSL) in complete remission (CR) after high-dose methotrexate (HD-MTX)-based chemotherapy has been proposed to minimize the neurotoxicity risk. Nevertheless, no study has focused on the survival impact of radiation parameters, as far as we know, and the optimal radiation schedule remains to be defined. The impact on outcome and neurologic performance of different radiation fields and doses was assessed in 33 patients with PCNSL who achieved CR after MTX-containing chemotherapy and were referred to consolidation whole-brain irradiation (WBRT). Patterns of relapse were analyzed on computed tomography-guided treatment planning, and neurologic impairment was assessed by the Mini Mental Status Examination. At a median follow-up of 50 months, 21 patients are relapse-free (5-year failure-free survival [FFS], 51%). WBRT doses ≥ 40 Gy were not associated with improved disease control in comparison with a WBRT dose of 30 to 36 Gy (relapse rate, 46% vs. 30%; 5-year FFS, 51% vs. 50%; p = 0.26). Disease control was not significantly different between patients irradiated to the tumor bed with 45 to 54 Gy or with 36 to 44 Gy, with a 5-year FFS of 35% and 44% (p = 0.43), respectively. Twenty patients are alive (5-year overall survival, 54%); WB and tumor bed doses did not have an impact on survival. Impairment as assessed by the Mini Mental Status Examination was significantly more common in patients treated with a WBRT dose ≥ 40 Gy. Consolidation with WBRT 36 Gy is advisable in patients with PCNSL in CR after HD-MTX-based chemotherapy. Higher doses do not change the outcome and could increase the risk of neurotoxicity. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Fractionated Radiotherapy with 3 x 8 Gy Induces Systemic Anti-Tumour Responses and Abscopal Tumour Inhibition without Modulating the Humoral Anti-Tumour Response

    PubMed Central

    Habets, Thomas H. P. M.; Oth, Tammy; Houben, Ans W.; Huijskens, Mirelle J. A. J.; Senden-Gijsbers, Birgit L. M. G.; Schnijderberg, Melanie C. A.; Brans, Boudewijn; Dubois, Ludwig J.; Lambin, Philippe; De Saint-Hubert, Marijke; Germeraad, Wilfred T. V.; Tilanus, Marcel G. J.; Mottaghy, Felix M.

    2016-01-01

    Accumulating evidence indicates that fractionated radiotherapy (RT) can result in distant non-irradiated (abscopal) tumour regression. Although preclinical studies indicate the importance of T cells in this infrequent phenomenon, these studies do not preclude that other immune mechanisms exhibit an addition role in the abscopal effect. We therefore addressed the question whether in addition to T cell mediated responses also humoral anti-tumour responses are modulated after fractionated RT and whether systemic dendritic cell (DC) stimulation can enhance tumour-specific antibody production. We selected the 67NR mammary carcinoma model since this tumour showed spontaneous antibody production in all tumour-bearing mice. Fractionated RT to the primary tumour was associated with a survival benefit and a delayed growth of a non-irradiated (contralateral) secondary tumour. Notably, fractionated RT did not affect anti-tumour antibody titers and the composition of the immunoglobulin (Ig) isotypes. Likewise, we demonstrated that treatment of tumour-bearing Balb/C mice with DC stimulating growth factor Flt3-L did neither modulate the magnitude nor the composition of the humoral immune response. Finally, we evaluated the immune infiltrate and Ig isotype content of the tumour tissue using flow cytometry and found no differences between treatment groups that were indicative for local antibody production. In conclusion, we demonstrate that the 67NR mammary carcinoma in Balb/C mice is associated with a pre-existing antibody response. And, we show that in tumour-bearing Balb/C mice with abscopal tumour regression such pre-existing antibody responses are not altered upon fractionated RT and/or DC stimulation with Flt3-L. Our research indicates that evaluating the humoral immune response in the setting of abscopal tumour regression is not invariably associated with therapeutic effects. PMID:27427766

  11. Upfront Systemic Chemotherapy and Short-Course Radiotherapy with Delayed Surgery for Locally Advanced Rectal Cancer with Distant Metastases: Outcomes, Compliance, and Favorable Prognostic Factors

    PubMed Central

    Kim, Tae Hyung; Ahn, Joong Bae; Jung, Minkyu; Kim, Tae Il; Kim, Hoguen; Shin, Sang Joon; Kim, Nam Kyu

    2016-01-01

    Purpose/Objective(s) Optimal treatment for locally advanced rectal cancer (LARC) with distant metastasis remains elusive. We aimed to evaluate upfront systemic chemotherapy and short-course radiotherapy (RT) followed by delayed surgery for such patients, and to identify favorable prognostic factors. Materials/Methods We retrospectively reviewed 50 LARC patients (cT4 or cT3, <2 mm from the mesorectal fascia) with synchronous metastatic disease. The primary endpoint was progression-free survival (PFS). The secondary endpoints were overall survival, treatment-related toxicity, and compliance. We considered P values <0.05 significant. Results At 22 months median follow-up, the median PFS time was 16 months and the 2-year PFS rate was 34.8%. Thirty-five patients who received radical surgery for primary and metastatic tumors were designated the curable group. Six patients with clinical complete response (ypCR) of metastases who underwent radical surgery for only the primary tumor were classified as potentially curable. Nine patients who received no radical surgery (3 received palliative surgery) were deemed the palliative group. The ypCR rate among surgery patients was 13.6%. PFS rates for the curable or potentially curable groups were significantly longer than that of the palliative group (P<0.001). On multivariate analysis, solitary organ metastasis and R0 status were independent prognostic factors for PFS. Conclusions These findings demonstrated that a strong possibility that upfront chemotherapy and short-course RT with delayed surgery are an effective alternative treatment for LARC with potentially resectable distant metastasis, owing to achievement of pathologic down-staging, R0 resection, and favorable compliance and toxicity, despite the long treatment duration. PMID:27536871

  12. Radiotherapy and Concomitant Intra-Arterial Docetaxel Combined With Systemic 5-Fluorouracil and Cisplatin for Oropharyngeal Cancer: A Preliminary Report-Improvement of Locoregional Control of Oropharyngeal Cancer

    SciTech Connect

    Oikawa, Hirobumi Nakamura, Ryuji; Nakasato, Tatsuhiko; Nishimura, Kohji; Sato, Hiroaki; Ehara, Shigeru

    2009-10-01

    Purpose: To confirm the advantage of chemoradiotherapy using intra-arterial docetaxel with intravenous cisplatin and 5-fluorouracil. Patients and Methods: A total of 26 oropharyngeal cancer patients (1, 2, 2, and 21 patients had Stage I, II, III, and IVa-IVc, respectively) were treated with two sessions of this chemoradiotherapy regimen. External beam radiotherapy was delivered using large portals that included the primary site and the regional lymph nodes initially (range, 40-41.4 Gy) and the metastatic lymph nodes later (60 or 72 Gy). All tumor-supplying branches of the carotid arteries were cannulated, and 40 mg/m{sup 2} docetaxel was individually infused on Day 1. The other systemic chemotherapy agents included 60 mg/m{sup 2} cisplatin on Day 2 and 500 mg/m{sup 2} 5-fluorouracil on Days 2-6. Results: The primary response of the tumor was complete in 21 (81%), partial in 4 (15%), and progressive in 1 patient. Grade 4 mucositis, leukopenia, and dermatitis was observed in 3, 2, and 1 patients, respectively. During a median follow-up of 10 months, the disease recurred at the primary site and at a distant organ in 2 (8%) and 3 (12%) patients, respectively. Three patients died because of cancer progression. Two patients (8%) with a partial response were compromised by lethal bleeding from the tumor bed or chemotherapeutic toxicity. The 3-year locoregional control rate and the 3-year overall survival rate was 73% and 77%, respectively. Conclusion: This method resulted in an excellent primary tumor response rate (96%) and moderate acute toxicity. Additional follow-up is required to ascertain the usefulness of this modality.

  13. [Radiotherapy for primary lung carcinoma].

    PubMed

    Giraud, P; Lacornerie, T; Mornex, F

    2016-09-01

    Indication, doses, technique of radiotherapy and concomitant chemotherapy, for primary lung carcinoma are presented. The recommendations for delineation of the target volumes and organs at risk are detailed.

  14. SU-E-P-48: Evaluation of Intensity Modulated Radiotherapy (IMRT) with Three Different Commercial Planning Systems for the Treatment of Cervical Cancer

    SciTech Connect

    Liu, D; Chi, Z; Yang, H; Miao, M; Jing, Z

    2015-06-15

    Purpose: To investigate the performances of three commercial treatment planning systems (TPS) for intensity modulated radiotherapy (IMRT) optimization regarding cervical cancer. Methods: For twenty cervical cancer patients, three IMRT plans were retrospectively re-planned: one with Pinnacle TPS,one with Oncentra TPS and on with Eclipse TPS. The total prescribed dose was 50.4 Gy delivered for PTV and 58.8 Gy for PTVnd by simultaneous integrated boost technique. The treatments were delivered using the Varian 23EX accelerator. All optimization schemes generated clinically acceptable plans. They were evaluated based on target coverage, homogeneity (HI) and conformity (CI). The organs at risk (OARs) were analyzed according to the percent volume under some doses and the maximum doses. The statistical method of the collected data of variance analysis was used to compare the difference among the quality of plans. Results: IMRT with Eclipse provided significant better HI, CI and all the parameters of PTV. However, the trend was not extension to the PTVnd, it was still significant better at mean dose, D50% and D98%, but plans with Oncentra showed significant better in the hight dosage volume, such as maximum dose and D2%. For the bladder wall, there were not notable difference among three groups, although Pinnacle and Oncentra systems provided a little lower dose sparing at V50Gy of bladder and rectal wall and V40Gy of bladder wall, respectively. V40Gy of rectal wall (p=0.037), small intestine (p=0.001 for V30Gy, p=0.010 for maximum dose) and V50Gy of right-femoral head (p=0.019) from Eclipse plans showed significant better than other groups. Conclusion: All SIB-IMRT plans were clinically acceptable which were generated by three commercial TPSs. The plans with Eclipse system showed advantages over the plans with Oncentra and Pinnacle system in the overwhelming majority of the dose coverage for targets and dose sparing of OARs in cervical cancer.

  15. [Radiotherapy of breast cancer].

    PubMed

    Hennequin, C; Barillot, I; Azria, D; Belkacémi, Y; Bollet, M; Chauvet, B; Cowen, D; Cutuli, B; Fourquet, A; Hannoun-Lévi, J M; Leblanc, M; Mahé, M A

    2016-09-01

    In breast cancer, radiotherapy is an essential component of the treatment. After conservative surgery for an infiltrating carcinoma, radiotherapy must be systematically performed, regardless of the characteristics of the disease, because it decreases the rate of local recurrence and by this way, specific mortality. Partial breast irradiation could not be proposed routinely but only in very selected and informed patients. For ductal carcinoma in situ, adjuvant radiotherapy must be also systematically performed after lumpectomy. After mastectomy, chest wall irradiation is required for pT3-T4 tumours and if there is an axillary nodal involvement, whatever the number of involved lymph nodes. After neo-adjuvant chemotherapy and mastectomy, in case of pN0 disease, chest wall irradiation is recommended if there is a clinically or radiologically T3-T4 or node positive disease before chemotherapy. Axillary irradiation is recommended only if there is no axillary surgical dissection and a positive sentinel lymph node. Supra and infra-clavicular irradiation is advised in case of positive axillary nodes. Internal mammary irradiation must be discussed case by case, according to the benefit/risk ratio (cardiac toxicity). Dose to the chest wall or the breast must be between 45-50Gy with a conventional fractionation. A boost dose over the tumour bed is required if the patient is younger than 60 years old. Hypofractionation (42.5 Gy in 16 fractions, or 41.6 Gy en 13 or 40 Gy en 15) is possible after tumorectomy and if a nodal irradiation is not mandatory. Delineation of the breast, the chest wall and the nodal areas are based on clinical and radiological evaluations. 3D-conformal irradiation is the recommended technique, intensity-modulated radiotherapy must be proposed only in case of specific clinical situations. Respiratory gating could be useful to decrease the cardiac dose. Concomitant administration of chemotherapy in unadvised, but hormonal treatment could be start with

  16. A quantification of the effectiveness of EPID dosimetry and software-based plan verification systems in detecting incidents in radiotherapy

    SciTech Connect

    Bojechko, Casey; Phillps, Mark; Kalet, Alan; Ford, Eric C.

    2015-09-15

    Purpose: Complex treatments in radiation therapy require robust verification in order to prevent errors that can adversely affect the patient. For this purpose, the authors estimate the effectiveness of detecting errors with a “defense in depth” system composed of electronic portal imaging device (EPID) based dosimetry and a software-based system composed of rules-based and Bayesian network verifications. Methods: The authors analyzed incidents with a high potential severity score, scored as a 3 or 4 on a 4 point scale, recorded in an in-house voluntary incident reporting system, collected from February 2012 to August 2014. The incidents were categorized into different failure modes. The detectability, defined as the number of incidents that are detectable divided total number of incidents, was calculated for each failure mode. Results: In total, 343 incidents were used in this study. Of the incidents 67% were related to photon external beam therapy (EBRT). The majority of the EBRT incidents were related to patient positioning and only a small number of these could be detected by EPID dosimetry when performed prior to treatment (6%). A large fraction could be detected by in vivo dosimetry performed during the first fraction (74%). Rules-based and Bayesian network verifications were found to be complimentary to EPID dosimetry, able to detect errors related to patient prescriptions and documentation, and errors unrelated to photon EBRT. Combining all of the verification steps together, 91% of all EBRT incidents could be detected. Conclusions: This study shows that the defense in depth system is potentially able to detect a large majority of incidents. The most effective EPID-based dosimetry verification is in vivo measurements during the first fraction and is complemented by rules-based and Bayesian network plan checking.

  17. A quantification of the effectiveness of EPID dosimetry and software-based plan verification systems in detecting incidents in radiotherapy.

    PubMed

    Bojechko, Casey; Phillps, Mark; Kalet, Alan; Ford, Eric C

    2015-09-01

    Complex treatments in radiation therapy require robust verification in order to prevent errors that can adversely affect the patient. For this purpose, the authors estimate the effectiveness of detecting errors with a "defense in depth" system composed of electronic portal imaging device (EPID) based dosimetry and a software-based system composed of rules-based and Bayesian network verifications. The authors analyzed incidents with a high potential severity score, scored as a 3 or 4 on a 4 point scale, recorded in an in-house voluntary incident reporting system, collected from February 2012 to August 2014. The incidents were categorized into different failure modes. The detectability, defined as the number of incidents that are detectable divided total number of incidents, was calculated for each failure mode. In total, 343 incidents were used in this study. Of the incidents 67% were related to photon external beam therapy (EBRT). The majority of the EBRT incidents were related to patient positioning and only a small number of these could be detected by EPID dosimetry when performed prior to treatment (6%). A large fraction could be detected by in vivo dosimetry performed during the first fraction (74%). Rules-based and Bayesian network verifications were found to be complimentary to EPID dosimetry, able to detect errors related to patient prescriptions and documentation, and errors unrelated to photon EBRT. Combining all of the verification steps together, 91% of all EBRT incidents could be detected. This study shows that the defense in depth system is potentially able to detect a large majority of incidents. The most effective EPID-based dosimetry verification is in vivo measurements during the first fraction and is complemented by rules-based and Bayesian network plan checking.

  18. Dosimetry in radiotherapy using a-Si EPIDs: Systems, methods, and applications focusing on 3D patient dose estimation

    NASA Astrophysics Data System (ADS)

    McCurdy, B. M. C.

    2013-06-01

    An overview is provided of the use of amorphous silicon electronic portal imaging devices (EPIDs) for dosimetric purposes in radiation therapy, focusing on 3D patient dose estimation. EPIDs were originally developed to provide on-treatment radiological imaging to assist with patient setup, but there has also been a natural interest in using them as dosimeters since they use the megavoltage therapy beam to form images. The current generation of clinically available EPID technology, amorphous-silicon (a-Si) flat panel imagers, possess many characteristics that make them much better suited to dosimetric applications than earlier EPID technologies. Features such as linearity with dose/dose rate, high spatial resolution, realtime capability, minimal optical glare, and digital operation combine with the convenience of a compact, retractable detector system directly mounted on the linear accelerator to provide a system that is well-suited to dosimetric applications. This review will discuss clinically available a-Si EPID systems, highlighting dosimetric characteristics and remaining limitations. Methods for using EPIDs in dosimetry applications will be discussed. Dosimetric applications using a-Si EPIDs to estimate three-dimensional dose in the patient during treatment will be overviewed. Clinics throughout the world are implementing increasingly complex treatments such as dynamic intensity modulated radiation therapy and volumetric modulated arc therapy, as well as specialized treatment techniques using large doses per fraction and short treatment courses (ie. hypofractionation and stereotactic radiosurgery). These factors drive the continued strong interest in using EPIDs as dosimeters for patient treatment verification.

  19. Benchmarking a novel ultrasound-CT fusion system for respiratory motion management in radiotherapy: assessment of spatio-temporal characteristics and comparison to 4DCT.

    PubMed

    Molloy, J A; Oldham, S A

    2008-01-01

    Management of respiratory motion during radiation therapy requires treatment planning and simulation using imaging modalities that possess sufficient spatio-temporal accuracy and precision. An investigation into the use of a novel ultrasound (US) imaging system for assessment of respiratory motion is presented, exploiting its good soft tissue contrast and temporal precision. The system dynamically superimposes the appropriate image plane sampled from a reference CT data set with the corresponding US B-mode image. An articulating arm is used for spatial registration. While the focus of the study was to quantify the system's ability to track respiratory motion, certain unique spatial calibration procedures were devised that render the software potentially valuable to the general research community. These include direct access to all transformation matrix elements and image scaling factors, a manual latency correction function, and a three-point spatial registration procedure that allows the system to be used in any room possessing a traditional radiotherapy laser localization system. Counter-intuitively, it was discovered that a manual procedure for calibrating certain transformation matrix elements produced superior accuracy to that of an algorithmic Levenberg-Marquardt optimization method. The absolute spatial accuracy was verified by comparing the physical locations of phantom test objects measured using the spatially registered US system, and using data from a 3DCT scan of the phantom as a reference. The spatial accuracy of the display superposition was also tested in a similar manner. The system's dynamic properties were then assessed using three methods. First, the overall system response time was studied using a programmable motion phantom. This included US video update, articulating arm update, CT data set resampling, and image display. The next investigation verified the system's ability to measure the range of motion of a moving anatomical test phantom that

  20. Benchmarking a novel ultrasound-CT fusion system for respiratory motion management in radiotherapy: Assessment of spatio-temporal characteristics and comparison to 4DCT

    SciTech Connect

    Molloy, J. A.; Oldham, S. A.

    2008-01-15

    Management of respiratory motion during radiation therapy requires treatment planning and simulation using imaging modalities that possess sufficient spatio-temporal accuracy and precision. An investigation into the use of a novel ultrasound (United States) imaging system for assessment of respiratory motion is presented, exploiting its good soft tissue contrast and temporal precision. The system dynamically superimposes the appropriate image plane sampled from a reference CT data set with the corresponding US B-mode image. An articulating arm is used for spatial registration. While the focus of the study was to quantify the system's ability to track respiratory motion, certain unique spatial calibration procedures were devised that render the software potentially valuable to the general research community. These include direct access to all transformation matrix elements and image scaling factors, a manual latency correction function, and a three-point spatial registration procedure that allows the system to be used in any room possessing a traditional radiotherapy laser localization system. Counter-intuitively, it was discovered that a manual procedure for calibrating certain transformation matrix elements produced superior accuracy to that of an algorithmic Levenberg-Marquardt optimization method. The absolute spatial accuracy was verified by comparing the physical locations of phantom test objects measured using the spatially registered US system, and using data from a 3DCT scan of the phantom as a reference. The spatial accuracy of the display superposition was also tested in a similar manner. The system's dynamic properties were then assessed using three methods. First, the overall system response time was studied using a programmable motion phantom. This included US video update, articulating arm update, CT data set resampling, and image display. The next investigation verified the system's ability to measure the range of motion of a moving anatomical test

  1. Long-term stability and mechanical characteristics of kV digital imaging system for proton radiotherapy

    SciTech Connect

    Zhu, Mingyao Botticello, Thomas; Lu, Hsiao-Ming; Winey, Brian

    2014-04-15

    Purpose: To quantitatively evaluate the long-term image panel positioning stability and gantry angle dependence for gantry-mounted kV imaging systems. Methods: For patient setup digital imaging systems in isocentric rotating proton beam delivery facilities, physical crosshairs are commonly inserted into the snout to define the kV x-ray beam isocenter. Utilizing an automatic detection algorithm, the authors analyzed the crosshair center positions in 2744 patient setup kV images acquired with the four imagers in two treatment rooms from January 2012 to January 2013. The crosshair position was used as a surrogate for imaging panel position, and its long-term stability at the four cardinal angles and the panel flex dependency on gantry angle was investigated. Results: The standard deviation of the panel position distributions was within 0.32 mm (with the range of variation less than ± 1.4 mm) in both the X-Z plane and Y direction. The mean panel inplane rotations were not more than 0.51° for the four panels at the cardinal angles, with standard deviations ≤0.26°. The panel position variations with gantry rotation due to gravity (flex) were within ±4 mm, and were panel-specific. Conclusions: The authors demonstrated that the kV image panel positions in our proton treatment system were highly reproducible at the cardinal angles over 13 months and also that the panel positions can be correlated to gantry angles. This result indicates that the kV image panel positions are stable over time; the amount of panel sag is predictable during gantry rotation and the physical crosshair for kV imaging may eventually be removed, with the imaging beam isocenter position routinely verified by adequate quality assurance procedures and measurements.

  2. Long-term stability and mechanical characteristics of kV digital imaging system for proton radiotherapy

    PubMed Central

    Zhu, Mingyao; Botticello, Thomas; Lu, Hsiao-Ming; Winey, Brian

    2014-01-01

    Purpose: To quantitatively evaluate the long-term image panel positioning stability and gantry angle dependence for gantry-mounted kV imaging systems. Methods: For patient setup digital imaging systems in isocentric rotating proton beam delivery facilities, physical crosshairs are commonly inserted into the snout to define the kV x-ray beam isocenter. Utilizing an automatic detection algorithm, the authors analyzed the crosshair center positions in 2744 patient setup kV images acquired with the four imagers in two treatment rooms from January 2012 to January 2013. The crosshair position was used as a surrogate for imaging panel position, and its long-term stability at the four cardinal angles and the panel flex dependency on gantry angle was investigated. Results: The standard deviation of the panel position distributions was within 0.32 mm (with the range of variation less than ± 1.4 mm) in both the X-Z plane and Y direction. The mean panel inplane rotations were not more than 0.51° for the four panels at the cardinal angles, with standard deviations ≤0.26°. The panel position variations with gantry rotation due to gravity (flex) were within ±4 mm, and were panel-specific. Conclusions: The authors demonstrated that the kV image panel positions in our proton treatment system were highly reproducible at the cardinal angles over 13 months and also that the panel positions can be correlated to gantry angles. This result indicates that the kV image panel positions are stable over time; the amount of panel sag is predictable during gantry rotation and the physical crosshair for kV imaging may eventually be removed, with the imaging beam isocenter position routinely verified by adequate quality assurance procedures and measurements. PMID:24694126

  3. Challenge and Hope in Radiotherapy of Hepatocellular Carcinoma

    PubMed Central

    2009-01-01

    Hepatocellular carcinoma (HCC) is one of the most critical global health issues. With frequent association of viral liver disease, HCC is highly complex, harboring both cancer and chronic liver disease. The tumor stage and underlying liver function are both major determinants of the treatment selection as well as prognosis in HCC patients, thus allowing no more than a 20% chance for potentially curative therapies. Radiotherapy technology has been evolved remarkably during the past decade, and radiation can be precisely delivered, thereby permitting higher doses to the tumour and reduced doses to surrounding normal tissues. There has been increasing interest in the merits of radiotherapy in HCC over the past few years, as indicated by a Pub Med search. Radiotherapy has been used as the definitive therapy with curative intent in early stage tumours. It has been used also in combination with TACE for intermediate stage tumours. In locally advanced tumours, radiotherapy has been combined with systemic agents. Despite its efficacy, radiotherapy has not yet been incorporated into the standard management guidelines of HCC. The lack of high evidence level data, especially randomized controlled trials, has posed an obstacle in including radiotherapy into the routine treatment schema of HCC. Therefore, well-designed prospective studies are strongly recommended using developing technology for radiotherapy alone or combination therapies. Also, many issues such as the optimal dose-fractionation, intra- or extrahepatic metastasis after radiotherapy, and radiation-induced hepatic dysfunction remain to be solved. In this review, current status of radiotherapy for HCC will be discussed with regard to technical consideration and combination strategy. The limitation and future perspectives will also be discussed. PMID:19881961

  4. Caring for children undergoing radiotherapy treatment: Swedish radiotherapy nurses' perceptions.

    PubMed

    Gårdling, J; Edwinson Månsson, M; Törnqvist, E; Hallström, I

    2015-12-01

    The aim was to explore radiotherapy nurses' perceptions of their experiences of caring for children undergoing radiotherapy treatment for cancer. Semi-structured interviews of 12 nurses were conducted. The interviews were analysed using a phenomenographical approach. All interviewees were women, and the group's mean age was 49 years. Caring for children during radiotherapy treatment was perceived as a complex task. Their perceptions included views on providing holistic care, creating a sense of security and being committed. Through holistic care the radiotherapy nurses took responsibility regarding care for the child and family, technical aspects of the radiotherapy procedure and the development of their profession. They tried to create a sense of security through individualized information and preparation, through teamwork with the child and family, and regarding anaesthetic personnel (if needed) while balancing the care they gave related to the child, to the family, to anaesthetic personnel, and to their own tasks. The radiotherapy nurses perceived themselves as committed in their care and reported being emotionally affected by sadness, but also joy. By clarifying radiotherapy nurses perceptions of caring for children guidelines can be developed to lessen anxiety and increase the sense of security amongst children undergoing radiotherapy treatment and their family members. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Design, construction and performance evaluation of the target tissue thickness measurement system in intraoperative radiotherapy for breast cancer

    NASA Astrophysics Data System (ADS)

    Yazdani, Mohammad Reza; Setayeshi, Saeed; Arabalibeik, Hossein; Akbari, Mohammad Esmaeil

    2017-05-01

    Intraoperative electron radiation therapy (IOERT), which uses electron beams for irradiating the target directly during the surgery, has the advantage of delivering a homogeneous dose to a controlled layer of tissue. Since the dose falls off quickly below the target thickness, the underlying normal tissues are spared. In selecting the appropriate electron energy, the accuracy of the target tissue thickness measurement is critical. In contrast to other procedures applied in IOERT, the routine measurement method is considered to be completely traditional and approximate. In this work, a novel mechanism is proposed for measuring the target tissue thickness with an acceptable level of accuracy. An electronic system has been designed and manufactured with the capability of measuring the tissue thickness based on the recorded electron density under the target. The results indicated the possibility of thickness measurement with a maximum error of 2 mm for 91.35% of data. Aside from system limitation in estimating the thickness of 5 mm phantom, for 88.94% of data, maximum error is 1 mm.

  6. TOPICAL REVIEW Dosimetry for ion beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Karger, Christian P.; Jäkel, Oliver; Palmans, Hugo; Kanai, Tatsuaki

    2010-11-01

    Recently, ion beam radiotherapy (including protons as well as heavier ions) gained considerable interest. Although ion beam radiotherapy requires dose prescription in terms of iso-effective dose (referring to an iso-effective photon dose), absorbed dose is still required as an operative quantity to control beam delivery, to characterize the beam dosimetrically and to verify dose delivery. This paper reviews current methods and standards to determine absorbed dose to water in ion beam radiotherapy, including (i) the detectors used to measure absorbed dose, (ii) dosimetry under reference conditions and (iii) dosimetry under non-reference conditions. Due to the LET dependence of the response of films and solid-state detectors, dosimetric measurements are mostly based on ion chambers. While a primary standard for ion beam radiotherapy still remains to be established, ion chamber dosimetry under reference conditions is based on similar protocols as for photons and electrons although the involved uncertainty is larger than for photon beams. For non-reference conditions, dose measurements in tissue-equivalent materials may also be necessary. Regarding the atomic numbers of the composites of tissue-equivalent phantoms, special requirements have to be fulfilled for ion beams. Methods for calibrating the beam monitor depend on whether passive or active beam delivery techniques are used. QA measurements are comparable to conventional radiotherapy; however, dose verification is usually single field rather than treatment plan based. Dose verification for active beam delivery techniques requires the use of multi-channel dosimetry systems to check the compliance of measured and calculated dose for a representative sample of measurement points. Although methods for ion beam dosimetry have been established, there is still room for developments. This includes improvement of the dosimetric accuracy as well as development of more efficient measurement techniques.

  7. SU-E-T-467: Implementation of Monte Carlo Dose Calculation for a Multileaf Collimator Equipped Robotic Radiotherapy System

    SciTech Connect

    Li, JS; Fan, J; Ma, C-M

    2015-06-15

    Purpose: To improve the treatment efficiency and capabilities for full-body treatment, a robotic radiosurgery system has equipped with a multileaf collimator (MLC) to extend its accuracy and precision to radiation therapy. To model the MLC and include it in the Monte Carlo patient dose calculation is the goal of this work. Methods: The radiation source and the MLC were carefully modeled to consider the effects of the source size, collimator scattering, leaf transmission and leaf end shape. A source model was built based on the output factors, percentage depth dose curves and lateral dose profiles measured in a water phantom. MLC leaf shape, leaf end design and leaf tilt for minimizing the interleaf leakage and their effects on beam fluence and energy spectrum were all considered in the calculation. Transmission/leakage was added to the fluence based on the transmission factors of the leaf and the leaf end. The transmitted photon energy was tuned to consider the beam hardening effects. The calculated results with the Monte Carlo implementation was compared with measurements in homogeneous water phantom and inhomogeneous phantoms with slab lung or bone material for 4 square fields and 9 irregularly shaped fields. Results: The calculated output factors are compared with the measured ones and the difference is within 1% for different field sizes. The calculated dose distributions in the phantoms show good agreement with measurements using diode detector and films. The dose difference is within 2% inside the field and the distance to agreement is within 2mm in the penumbra region. The gamma passing rate is more than 95% with 2%/2mm criteria for all the test cases. Conclusion: Implementation of Monte Carlo dose calculation for a MLC equipped robotic radiosurgery system is completed successfully. The accuracy of Monte Carlo dose calculation with MLC is clinically acceptable. This work was supported by Accuray Inc.

  8. A biological tissue adhesive and dissolvent system for intraocular tumor plaque radiotherapy: an in vivo animal model experiment.

    PubMed

    Zloto, Ofira; Alezra, Dror; Sagiv, Oded; Belkin, Michael; Dai, Vicktoria Vishnevskia; Moroz, Iris; Greenberg, Gahl; Ben-Artsi, Elad; Fabian, Ido Didi

    2015-11-01

    To examine a novel biological adhesive and dissolvent system for plaque placement and removal using fibrin glue and urokinase, respectively, in an in vivo animal model. The study was performed on 23 rabbit eyes. Of these, eight underwent a technical feasibility study and ultrasonographic plaque displacement measurements, nine were examined clinically and by magnetic resonance imaging and histopathology for tissue reaction to the biological substances used, and in six the impact of fibrin glue as an orbital space occupier on intraocular pressure was assessed. In an additional ex vivo experiment, the glue's radiation attenuating properties were tested using an oncology EDR2 film. Plaque horizontal movement throughout follow-up (7-10 days) was negligible (0.5 ± 0.2 mm), and there was no tilting whatsoever. In the tissue response experiment, no adverse effects were recorded after application of fibrin or urokinase throughout the 21-day follow-up period. Interestingly, a circumscribed local inflammatory response was noted in tissue surrounding the fibrin glue, and persisted at 21 days. In the orbital space-occupying experiment, application of 1 cc fibrin glue did not cause a significant elevation in intraocular pressure (IOP) (P = 0.06), and in the ex vivo experiment, there was no significant difference between radiation readings with and without glue separation of the radioactive sources and film (P = 0.065). The adhesive and dissolvent system was feasible and safe for plaque placement and removal. It may be superior to conventional surgical plaque placement methods in eliminating the relatively common risk of plaque tilting and complications due to scleral suturing.

  9. Incidence of radiation toxicity in cervical cancer and endometrial cancer patients treated with radiotherapy alone versus adjuvant radiotherapy

    PubMed Central

    Roszak, Andrzej; Wareńczak-Florczak, Żaneta; Bratos, Krystyna; Milecki, Piotr

    2012-01-01

    Aim The study was made to evaluate early and late toxicity in a diversified group of patients receiving definitive or adjuvant radiotherapy in terms of clinical diagnosis and treatment methods. Background Radiotherapy is a standard way of treatment in cervical and endometrial cancer patients, both as definitive and adjuvant therapy. But every radiation treatment may be involved with toxicity. Materials and methods A detailed analysis was performed of 263 patients with gynaecological cancer treated with definitive (90 patients with cervical cancer received radiochemotherapy or radiotherapy exclusively) and adjuvant radiotherapy (38 with cervical and 135 with endometrial cancer). Results Acute reactions were found in 51.3% and late reactions were found in 14.8% of patients. It was stated that early (p < 0.007) and late (p < 0.003) post radiation reaction appear more frequently in women treated with definitive than adjuvant radiotherapy. The analysis of the whole group revealed higher rate of toxicity, both early and late, in the gastrointestinal tract than in the urinary system (p < 0.004). Comparing the subgroups, it was found that intestinal reactions occurred more frequently in the definitive radiotherapy group than in the adjuvant one. The occurrence of side effects was associated with the prolongation of total irradiation time due to necessary interruptions of radiotherapy. The comparison of the subgroups showed that interruptions occurred more frequently in patients receiving definitive rather than adjuvant radiotherapy (17.7–2.9%). Conclusions Definitive radiotherapy compared with adjuvant treatment may by associated with higher percentage of side effects caused by dose of therapy and correlation with chemotherapy. PMID:24377035

  10. SU-E-T-76: A Software System to Monitor VMAT Plan Complexity in a Large Radiotherapy Centre

    SciTech Connect

    Arumugam, S; Xing, A; Vial, P; Thwaites, D; Holloway, L

    2015-06-15

    Purpose: To develop a system that analyses and reports the complexity of Volumetric Modulated Arc Therapy (VMAT) plans to aid in the decision making for streamlining patient specific dosimetric quality assurance (QA) tests. Methods: A software system, Delcheck, was developed in-house to calculate VMAT plan and delivery complexity using the treatment delivery file. Delcheck has the functionality to calculate multiple plan complexity metrics including the Li-Xing Modulation Index (LI-MI), multiplicative combination of Leaf Travel and Modulation Complexity Score (LTMCSv), Monitor Units per prescribed dose (MU/D) and the delivery complexity index (MIt) that incorporates the modulation of dose rate, leaf speed and gantry speed. Delcheck includes database functionality to store and compare plan metrics for a specified treatment site. The overall plan and delivery complexity is assessed based on the 95% conformance limit of the complexity metrics as Similar, More or Less complex. The functionality of the software was tested using 42 prostate conventional, 10 prostate SBRT and 15 prostate bed VMAT plans generated for an Elekta linear accelerator. Results: The mean(σ) of LI-MI for conventional, SBRT and prostate bed plans were 1690(486), 3215.4(1294) and 3258(982) respectively. The LTMCSv of the studied categories were 0.334(0.05), 0.325(0.07) and 0.3112(0.09). The MU/D of the studied categories were 2.4(0.4), 2.7(0.7) and 2.5(0.5). The MIt of the studied categories were 21.6(3.4), 18.2(3.0) and 35.9(6.6). The values of the complexity metrics show that LI-MI appeared to resolve the plan complexity better than LTMCSv and MU/D. The MIt value increased as the delivery complexity increased. Conclusion: The developed software was shown to be working as expected. In studied treatment categories Prostate bed plans are more complex in both plan and delivery and SBRT is more complex in plan and less complex in delivery as demonstrated by LI-MI and MIt. This project was funded

  11. SU-E-T-648: Quality Assurance Using the RADPOS System for 4D Radiotherapy with CyberKnife

    SciTech Connect

    Marants, R; Vandervoort, E; Cygler, J E

    2015-06-15

    Purpose: The CyberKnife robotic radiosurgery system uses Synchrony respiratory motion compensation, which requires independent performance verification. In this work, the RADPOS 4D dosimetry system’s motion measurements are compared with internal fiducial position measurements. In addition, RADPOS measurements are compared with Synchrony’s predictive correlation model, which is based on internal fiducial and external LED marker position measurements. Methods: A treatment plan was created for a lung insert containing fiducials, RADPOS detector, and Solid Water tumor phantom. Two Quasar Respiratory Motion Phantoms (Q1 and Q2) and two RADPOS detectors (R1 and R2) were used: Q1 simulated lung motion with a lung insert moving in the superior/inferior direction, while Q2 simulated chest motion with a chest platform moving in the anterior/posterior direction. Before treatment, R1 was secured inside of the tumor phantom within Q1, while LED markers and R2 were positioned on the chest platform of Q2. Two treatment delivery cases were studied: isocentric plan (I) and non-isocentric patient plan (P). Four motion cases were studied: no motion (0), sinusoidal and in-phase (1), sinusoidal and out-of-phase (2), patient waveform and out-of-phase (3). A coordinate alignment algorithm was implemented, allowing RADPOS and model position data to be compared within the fiducial coordinate system. Results: The standard deviation of the differences between RADPOS and fiducial position measurements was below 0.6 mm for all experimental cases. The standard deviation of the differences between RADPOS and model position data was 1.0, 1.5, and 1.6 mm along the primary direction of motion for case I1, I2, and P3, respectively. Conclusion: Our work demonstrates that RADPOS is a useful tool for independent quality assurance of CyberKnife treatment with Synchrony respiratory compensation. RADPOS and fiducial position measurement closely match, and RADPOS confirms the effectiveness of Cyber

  12. SU-E-T-190: First Integration of Steriotactic Radiotherapy Planning System Iplan with Elekta Linear Accelerator

    SciTech Connect

    Biplab, S; Soumya, R; Paul, S; Jassal, K; Munshi, A; Giri, U; Kumar, V; Roy, S; Ganesh, T; Mohanti, B

    2014-06-01

    Purpose: For the first time in the world, BrainLAB has integrated its iPlan treatment planning system for clinical use with Elekta linear accelerator (Axesse with a Beam Modulator). The purpose of this study was to compare the calculated and measured doses with different chambers to establish the calculation accuracy of iPlan system. Methods: The iPlan has both Pencil beam (PB) and Monte Carlo (MC) calculation algorithms. Beam data include depth doses, profiles and output measurements for different field sizes. Collected data was verified by vendor and beam modelling was done. Further QA tests were carried out in our clinic. Dose calculation accuracy verified point, volumetric dose measurement using ion chambers of different volumes (0.01cc and 0.125cc). Planner dose verification was done using diode array. Plans were generated in iPlan and irradiated in Elekta Axesse linear accelerator. Results: Dose calculation accuracies verified using ion chamber for 6 and 10 MV beam were 3.5+/-0.33(PB), 1.7%+/-0.7(MC) and 3.9%+/-0.6(PB), 3.4%+/-0.6(MC) respectively. Using a pin point chamber, dose calculation accuracy for 6MV and 10MV was 3.8%+/-0.06(PB), 1.21%+/-0.2(MC) and 4.2%+/-0.6(PB), 3.1%+/-0.7(MC) respectively. The calculated planar dose distribution for 10.4×10.4 cm2 was verified using a diode array and the gamma analysis for 2%-2mm criteria yielded pass rates of 88 %(PB) and 98.8%(MC) respectively. 3mm-3% yields 100% passing for both MC and PB algorithm. Conclusion: Dose calculation accuracy was found to be within acceptable limits for MC for 6MV beam. PB for both beams and MC for 10 MV beam were found to be outside acceptable limits. The output measurements were done twice for conformation. The lower gamma matching was attributed to meager number of measured profiles (only two profiles for PB) and coarse measurement resolution for diagonal profile measurement (5mm). Based on these measurements we concluded that 6 MV MC algorithm is suitable for patient treatment.

  13. Effect of audio instruction on tracking errors using a four-dimensional image-guided radiotherapy system.

    PubMed

    Nakamura, Mitsuhiro; Sawada, Akira; Mukumoto, Nobutaka; Takahashi, Kunio; Mizowaki, Takashi; Kokubo, Masaki; Hiraoka, Masahiro

    2013-09-06

    The Vero4DRT (MHI-TM2000) is capable of performing X-ray image-based tracking (X-ray Tracking) that directly tracks the target or fiducial markers under continuous kV X-ray imaging. Previously, we have shown that irregular respiratory patterns increased X-ray Tracking errors. Thus, we assumed that audio instruction, which generally improves the periodicity of respiration, should reduce tracking errors. The purpose of this study was to assess the effect of audio instruction on X-ray Tracking errors. Anterior-posterior abdominal skin-surface displacements obtained from ten lung cancer patients under free breathing and simple audio instruction were used as an alternative to tumor motion in the superior-inferior direction. First, a sequential predictive model based on the Levinson-Durbin algorithm was created to estimate the future three-dimensional (3D) target position under continuous kV X-ray imaging while moving a steel ball target of 9.5 mm in diameter. After creating the predictive model, the future 3D target position was sequentially calculated from the current and past 3D target positions based on the predictive model every 70 ms under continuous kV X-ray imaging. Simultaneously, the system controller of the Vero4DRT calculated the corresponding pan and tilt rotational angles of the gimbaled X-ray head, which then adjusted its orientation to the target. The calculated and current rotational angles of the gimbaled X-ray head were recorded every 5 ms. The target position measured by the laser displacement gauge was synchronously recorded every 10 msec. Total tracking system errors (ET) were compared between free breathing and audio instruction. Audio instruction significantly improved breathing regularity (p < 0.01). The mean ± standard deviation of the 95th percentile of ET (E95T ) was 1.7 ± 0.5 mm (range: 1.1-2.6mm) under free breathing (E95T,FB) and 1.9 ± 0.5 mm (range: 1.2-2.7 mm) under audio instruction (E95T,AI). E95T,AI was larger than E95T,FB for

  14. Reducing scan angle using adaptive prior knowledge for a limited-angle intrafraction verification (LIVE) system for conformal arc radiotherapy

    NASA Astrophysics Data System (ADS)

    Zhang, Yawei; Yin, Fang-Fang; Zhang, You; Ren, Lei

    2017-05-01

    The purpose of this study is to develop an adaptive prior knowledge guided image estimation technique to reduce the scan angle needed in the limited-angle intrafraction verification (LIVE) system for 4D-CBCT reconstruction. The LIVE system has been previously developed to reconstruct 4D volumetric images on-the-fly during arc treatment for intrafraction target verification and dose calculation. In this study, we developed an adaptive constrained free-form deformation reconstruction technique in LIVE to further reduce the scanning angle needed to reconstruct the 4D-CBCT images for faster intrafraction verification. This technique uses free form deformation with energy minimization to deform prior images to estimate 4D-CBCT based on kV-MV projections acquired in extremely limited angle (orthogonal 3°) during the treatment. Note that the prior images are adaptively updated using the latest CBCT images reconstructed by LIVE during treatment to utilize the continuity of the respiratory motion. The 4D digital extended-cardiac-torso (XCAT) phantom and a CIRS 008A dynamic thoracic phantom were used to evaluate the effectiveness of this technique. The reconstruction accuracy of the technique was evaluated by calculating both the center-of-mass-shift (COMS) and 3D volume-percentage-difference (VPD) of the tumor in reconstructed images and the true on-board images. The performance of the technique was also assessed with varied breathing signals against scanning angle, lesion size, lesion location, projection sampling interval, and scanning direction. In the XCAT study, using orthogonal-view of 3° kV and portal MV projections, this technique achieved an average tumor COMS/VPD of 0.4  ±  0.1 mm/5.5  ±  2.2%, 0.6  ±  0.3 mm/7.2  ±  2.8%, 0.5  ±  0.2 mm/7.1  ±  2.6%, 0.6  ±  0.2 mm/8.3  ±  2.4%, for baseline drift, amplitude variation, phase shift, and patient breathing signal variation

  15. Precision, high dose radiotherapy. II. Helium ion treatment of tumors adjacent to critical central nervous system structures

    SciTech Connect

    Saunders, W.M.; Chen, G.T.Y.; Austin-Seymour, M.; Castro, J.R.; Collier, J.M.; Gauger, G.; Gutin, P.; Phillips, T.L.; Pitluck, S.; Walton, R.E.

    1985-07-01

    In this paper, the authors present a technique for treating relatively small, low grade tumors located very close to critical, radiation sensitive central nervous system structures such as the spinal cord and the brain stem. A beam of helium ions is used to irradiate the tumor. The nearby normal tissues are protected by exploiting the superb dose localization properties of this beam, particularly its well defined and controllable range in tissue, the increased dose deposited near the end of this range (i.e., the Bragg peak), the sharp decrease in dose beyond the Bragg peak, and the sharp penumbra of the beam. To illustrate the technique, the authors present a group of 19 patients treated for chordomas, meningiomas and low grade chondrosarcomas in the base of the skull or spinal column. They have been able to deliver high, uniform doses to the target volumes, while keeping the doses to the nearby critical tissues below the threshold for radiation damage. Follow-up on this group of patients is short, averaging 22 months (2 to 75 months). Currently, 15 patients have local control of their tumor. Two major complications, a spinal cord transsection and optic tract damage, are discussed in detail. Their treatment policies have been modified to minimize the risk of these complications in the future, and they are continuing to use this method to treat such patients.

  16. Development of an ultrasmall C-band linear accelerator guide for a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head.

    PubMed

    Kamino, Yuichiro; Miura, Sadao; Kokubo, Masaki; Yamashita, Ichiro; Hirai, Etsuro; Hiraoka, Masahiro; Ishikawa, Junzo

    2007-05-01

    We are developing a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head. It is capable of pursuing irradiation and delivering irradiation precisely with the help of an agile moving x-ray head on the gimbals. Requirements for the accelerator guide were established, system design was developed, and detailed design was conducted. An accelerator guide was manufactured and basic beam performance and leakage radiation from the accelerator guide were evaluated at a low pulse repetition rate. The accelerator guide including the electron gun is 38 cm long and weighs about 10 kg. The length of the accelerating structure is 24.4 cm. The accelerating structure is a standing wave type and is composed of the axial-coupled injector section and the side-coupled acceleration cavity section. The injector section is composed of one prebuncher cavity, one buncher cavity, one side-coupled half cavity, and two axial coupling cavities. The acceleration cavity section is composed of eight side-coupled nose reentrant cavities and eight coupling cavities. The electron gun is a diode-type gun with a cerium hexaboride (CeB6) direct heating cathode. The accelerator guide can be operated without any magnetic focusing device. Output beam current was 75 mA with a transmission efficiency of 58%, and the average energy was 5.24 MeV. Beam energy was distributed from 4.95 to 5.6 MeV. The beam profile, measured 88 mm from the beam output hole on the axis of the accelerator guide, was 0.7 mm X 0.9 mm full width at half maximum (FWHM) width. The beam loading line was 5.925 (MeV)-Ib (mA) X 0.00808 (MeV/mA), where Ib is output beam current. The maximum radiation leakage of the accelerator guide at 100 cm from the axis of the accelerator guide was calculated as 0.33 cGy/min at the rated x-ray output of 500 cGy/min from the measured value. This leakage requires no radiation shielding for the accelerator guide itself per IEC 60601-2-1.

  17. Ghost marker detection and elimination in marker-based optical tracking systems for real-time tracking in stereotactic body radiotherapy

    SciTech Connect

    Yan, Guanghua Li, Jonathan; Huang, Yin; Mittauer, Kathryn; Lu, Bo; Liu, Chihray

    2014-10-15

    Purpose: To propose a simple model to explain the origin of ghost markers in marker-based optical tracking systems (OTS) and to develop retrospective strategies to detect and eliminate ghost markers. Methods: In marker-based OTS, ghost markers are virtual markers created due to the cross-talk between the two camera sensors, which can lead to system execution failure or inaccuracy in patient tracking. As a result, the users have to limit the number of markers and avoid certain marker configurations to reduce the chances of ghost markers. In this work, the authors propose retrospective strategies to detect and eliminate ghost markers. The two camera sensors were treated as mathematical points in space. The authors identified the coplanar within limit (CWL) condition as the necessary condition for ghost marker occurrence. A simple ghost marker detection method was proposed based on the model. Ghost marker elimination was achieved through pattern matching: a ghost marker-free reference set was matched with the optical marker set observed by the OTS; unmatched optical markers were eliminated as either ghost markers or misplaced markers. The pattern matching problem was formulated as a constraint satisfaction problem (using pairwise distances as constraints) and solved with an iterative backtracking algorithm. Wildcard markers were introduced to address missing or misplaced markers. An experiment was designed to measure the sensor positions and the limit for the CWL condition. The ghost marker detection and elimination algorithms were verified with samples collected from a five-marker jig and a nine-marker anthropomorphic phantom, rotated with the treatment couch from −60° to +60°. The accuracy of the pattern matching algorithm was further validated with marker patterns from 40 patients who underwent stereotactic body radiotherapy (SBRT). For this purpose, a synthetic optical marker pattern was created for each patient by introducing ghost markers, marker position

  18. SU-E-J-182: Reproducibility of Tumor Motion Probability Distribution Function in Stereotactic Body Radiation Therapy of Lung Using Real-Time Tumor-Tracking Radiotherapy System

    SciTech Connect

    Shiinoki, T; Hanazawa, H; Park, S; Takahashi, T; Shibuya, K; Kawamura, S; Uehara, T; Yuasa, Y; Koike, M

    2015-06-15

    Purpose: We aim to achieve new four-dimensional radiotherapy (4DRT) using the next generation real-time tumor-tracking (RTRT) system and flattening-filter-free techniques. To achieve new 4DRT, it is necessary to understand the respiratory motion of tumor. The purposes of this study were: 1.To develop the respiratory motion analysis tool using log files. 2.To evaluate the reproducibility of tumor motion probability distribution function (PDF) during stereotactic body RT (SBRT) of lung tumor. Methods: Seven patients having fiducial markers closely implanted to the lung tumor were enrolled in this study. The positions of fiducial markers were measured using the RTRT system (Mitsubishi Electronics Co., JP) and recorded as two types of log files during the course of SBRT. For each patients, tumor motion range and tumor motion PDFs in left-right (LR), anterior-posterior (AP) and superior-inferior (SI) directions were calculated using log files of all beams per fraction (PDFn). Fractional PDF reproducibility (Rn) was calculated as Kullback-Leibler (KL) divergence between PDF1 and PDFn of tumor motion. The mean of Rn (Rm) was calculated for each patient and correlated to the patient’s mean tumor motion range (Am). The change of Rm during the course of SBRT was also evluated. These analyses were performed using in-house developed software. Results: The Rm were 0.19 (0.07–0.30), 0.14 (0.07–0.32) and 0.16 (0.09–0.28) in LR, AP and SI directions, respectively. The Am were 5.11 mm (2.58–9.99 mm), 7.81 mm (2.87–15.57 mm) and 11.26 mm (3.80–21.27 mm) in LR, AP and SI directions, respectively. The PDF reproducibility decreased as the tumor motion range increased in AP and SI direction. That decreased slightly through the course of RT in SI direction. Conclusion: We developed the respiratory motion analysis tool for 4DRT using log files and quantified the range and reproducibility of respiratory motion for lung tumors.

  19. EURAMET.RI(I)-S7 comparison of alanine dosimetry systems for absorbed dose to water measurements in gamma- and x-radiation at radiotherapy levels

    NASA Astrophysics Data System (ADS)

    Garcia, Tristan; Anton, Mathias; Sharpe, Peter

    2012-01-01

    The National Physical Laboratory (NPL), the Physikalisch-Technische Bundesanstalt (PTB) and the Laboratoire National Henri Becquerel (LNE-LNHB) are involved in the European project 'External Beam Cancer Therapy', a project of the European Metrology Research Programme. Within this project, the electron paramagnetic resonance (EPR)/alanine dosimetric method has been chosen for performing measurements in small fields such as those used in IMRT (intensity modulated radiation therapy). In this context, these three National Metrology Institutes (NMI) wished to compare the result of their alanine dosimetric systems (detector, modus operandi etc) at radiotherapy dose levels to check their consistency. This EURAMET.RI(I)-S7 comparison has been performed with the support of the Bureau International des Poids et Mesures (BIPM) which collected and distributed the results as a neutral organization, to ensure the comparison was 'blind'. Irradiations have been made under reference conditions by each laboratory in a 60Co beam and in an accelerator beam (10 MV or 12 MV) in a water phantom of 30 cm × 30 cm × 30 cm in a square field of 10 cm × 10 cm at the reference depth. Irradiations have been performed at known values of absorbed dose to water (Dw) within 10% of nominal doses of 5 Gy and 10 Gy, i.e. between 4.5 Gy and 5.5 Gy and between 9 Gy and 11 Gy, respectively. Each participant read out their dosimeters and assessed the doses using their own protocol (calibration curve, positioning device etc) as this comparison aims at comparing the complete dosimetric process. The results demonstrate the effectiveness of the EPR/alanine dosimetry systems operated by National Metrology Institutes as a method of assuring therapy level doses with the accuracy required. The maximum deviation in the ratio of measured to applied dose is less than 1%. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key

  20. Clinical experience using a video-guided spirometry system for deep inhalation breath-hold radiotherapy of left-sided breast cancer.

    PubMed

    Yang, Wensha; McKenzie, Elizabeth M; Burnison, Michele; Shiao, Stephen; Mirhadi, Amin; Hakimian, Behrooz; Reznik, Robert; Tuli, Richard; Sandler, Howard; Fraass, Benedick A

    2015-03-08

    The purpose was to report clinical experience of a video-guided spirometry system in applying deep inhalation breath-hold (DIBH) radiotherapy for left-sided breast cancer, and to study the systematic and random uncertainties, intra- and interfraction motion and impact on cardiac dose associated with DIBH. The data from 28 left-sided breast cancer patients treated with spirometer-guided DIBH radiation were studied. Dosimetric comparisons between free-breathing (FB) and DIBH plans were performed. The distance between the heart and chest wall measured on the digitally reconstructed radiographs (DRR) and MV portal images, dDRR(DIBH) and dport(DIBH), respectively, was compared as a measure of DIBH setup uncertainty. The difference (Δd) between dDRR(DIBH) and dport(DIBH) was defined as the systematic uncertainty. The standard deviation of Δd for each patient was defined as the random uncertainty. MV cine images during radiation were acquired. Affine registrations of the cine images acquired during one fraction and multiple fractions were performed to study the intra- and interfraction motion of the chest wall. The median chest wall motion was used as the metric for intra- and interfraction analysis. Breast motions in superior-inferior (SI) direction and "AP" (defined on the DRR or MV portal image as the direction perpendicular to the SI direction) are reported. Systematic and random uncertainties of 3.8 mm and 2mm, respectively, were found for this spirometer-guided DIBH treatment. MV cine analysis showed that intrafraction chest wall motions during DIBH were 0.3mm in "AP" and 0.6 mm in SI. The interfraction chest wall motions were 3.6 mm in "AP" and 3.4 mm in SI. Utilization of DIBH with this spirometry system led to a statistically significant reduction of cardiac dose relative to FB treatment. The DIBH using video-guided spirometry provided reproducible cardiac sparing with minimal intra- and interfraction chest wall motion, and thus is a valuable adjunct to modern

  1. Demand for radiotherapy in Spain.

    PubMed

    Rodríguez, A; Borrás, J M; López-Torrecilla, J; Algara, M; Palacios-Eito, A; Gómez-Caamaño, A; Olay, L; Lara, P C

    2017-02-01

    Assessing the demand for radiotherapy in Spain based on existing evidence to estimate the human resources and equipment needed so that every person in Spain has access to high-quality radiotherapy when they need it. We used data from the European Cancer Observatory on the estimated incidence of cancer in Spain in 2012, along with the evidence-based indications for radiotherapy developed by the Australian CCORE project, to obtain an optimal radiotherapy utilisation proportion (OUP) for each tumour. About 50.5 % of new cancers in Spain require radiotherapy at least once over the course of the disease. Additional demand for these services comes from reradiation therapy and non-melanoma skin cancer. Approximately, 25-30 % of cancer patients with an indication for radiotherapy do not receive it due to factors that include access, patient preference, familiarity with the treatment among physicians, and especially resource shortages, all of which contribute to its underutilisation. Radiotherapy is underused in Spain. The increasing incidence of cancer expected over the next decade and the greater frequency of reradiations necessitate the incorporation of radiotherapy demand into need-based calculations for cancer services planning.

  2. Particle radiotherapy for prostate cancer.

    PubMed

    Shioyama, Yoshiyuki; Tsuji, Hiroshi; Suefuji, Hiroaki; Sinoto, Makoto; Matsunobu, Akira; Toyama, Shingo; Nakamura, Katsumasa; Kudo, Sho

    2015-01-01

    Recent advances in external beam radiotherapy have allowed us to deliver higher doses to the tumors while decreasing doses to the surrounding tissues. Dose escalation using high-precision radiotherapy has improved the treatment outcomes of prostate cancer. Intensity-modulated radiation therapy has been widely used throughout the world as the most advanced form of photon radiotherapy. In contrast, particle radiotherapy has also been under development, and has been used as an effective and non-invasive radiation modality for prostate and other cancers. Among the particles used in such treatments, protons and carbon ions have the physical advantage that the dose can be focused on the tumor with only minimal exposure of the surrounding normal tissues. Furthermore, carbon ions also have radiobiological advantages that include higher killing effects on intrinsic radio-resistant tumors, hypoxic tumor cells and tumor cells in the G0 or S phase. However, the degree of clinical benefit derived from these theoretical advantages in the treatment of prostate cancer has not been adequately determined. The present article reviews the available literature on the use of particle radiotherapy for prostate cancer as well as the literature on the physical and radiobiological properties of this treatment, and discusses the role and the relative merits of particle radiotherapy compared with current photon-based radiotherapy, with a focus on proton beam therapy and carbon ion radiotherapy.

  3. Investigation of uncertainties in image registration of cone beam CT to CT on an image-guided radiotherapy system.

    PubMed

    Sykes, J R; Brettle, D S; Magee, D R; Thwaites, D I

    2009-12-21

    Methods of measuring uncertainties in rigid body image registration of fan beam computed tomography (FBCT) to cone beam CT (CBCT) have been developed for automatic image registration algorithms in a commercial image guidance system (Synergy, Elekta, UK). The relationships between image registration uncertainty and both imaging dose and image resolution have been investigated with an anthropomorphic skull phantom and further measurements performed with patient images of the head. A new metric of target registration error is proposed. The metric calculates the mean distance traversed by a set of equi-spaced points on the surface of a 5 cm sphere, centred at the isocentre when transformed by the residual error of registration. Studies aimed at giving practical guidance on the use of the Synergy automated image registration, including choice of algorithm and use of the Clipbox are reported. The chamfer-matching algorithm was found to be highly robust to the increased noise induced by low-dose acquisitions. This would allow the imaging dose to be reduced from the current clinical norm of 2 mGy to 0.2 mGy without a clinically significant loss of accuracy. A study of the effect of FBCT slice thickness/spacing and CBCT voxel size showed that 2.5 mm and 1 mm, respectively, gave acceptable image registration performance. Registration failures were highly infrequent if the misalignment was typical of normal clinical set-up errors and these were easily identified. The standard deviation of translational registration errors, measured with patient images, was 0.5 mm on the surface of a 5 cm sphere centred on the treatment centre. The chamfer algorithm is suitable for routine clinical use with minimal need for close inspection of image misalignment.

  4. Investigation of uncertainties in image registration of cone beam CT to CT on an image-guided radiotherapy system

    NASA Astrophysics Data System (ADS)

    Sykes, J. R.; Brettle, D. S.; Magee, D. R.; Thwaites, D. I.

    2009-12-01

    Methods of measuring uncertainties in rigid body image registration of fan beam computed tomography (FBCT) to cone beam CT (CBCT) have been developed for automatic image registration algorithms in a commercial image guidance system (Synergy, Elekta, UK). The relationships between image registration uncertainty and both imaging dose and image resolution have been investigated with an anthropomorphic skull phantom and further measurements performed with patient images of the head. A new metric of target registration error is proposed. The metric calculates the mean distance traversed by a set of equi-spaced points on the surface of a 5 cm sphere, centred at the isocentre when transformed by the residual error of registration. Studies aimed at giving practical guidance on the use of the Synergy automated image registration, including choice of algorithm and use of the Clipbox are reported. The chamfer-matching algorithm was found to be highly robust to the increased noise induced by low-dose acquisitions. This would allow the imaging dose to be reduced from the current clinical norm of 2 mGy to 0.2 mGy without a clinically significant loss of accuracy. A study of the effect of FBCT slice thickness/spacing and CBCT voxel size showed that 2.5 mm and 1 mm, respectively, gave acceptable image registration performance. Registration failures were highly infrequent if the misalignment was typical of normal clinical set-up errors and these were easily identified. The standard deviation of translational registration errors, measured with patient images, was 0.5 mm on the surface of a 5 cm sphere centred on the treatment centre. The chamfer algorithm is suitable for routine clinical use with minimal need for close inspection of image misalignment.

  5. CHOD/BVAM Chemotherapy and Whole-Brain Radiotherapy for Newly Diagnosed Primary Central Nervous System Lymphoma

    SciTech Connect

    Laack, Nadia N.; O'Neill, Brian Patrick; Ballman, Karla V.; O'Fallon, Judith Rich; Carrero, Xiomara W.; Kurtin, Paul J.; Scheithauer, Bernd W.; Brown, Paul D.; Habermann, Thomas M.; Colgan, Joseph P.; Gilbert, Mark R.; Hawkins, Roland B.; Morton, Roscoe F.; Windschitl, Harry E.; Fitch, Tom R.; Pajon, Eduardo R.

    2011-10-01

    Purpose: To assess the efficacy and toxicity of chemotherapy consisting of cyclophosphamide, doxorubicin (Adriamycin), vincristine, and dexamethasone (CHOD) plus bis-chloronitrosourea (BCNU), cytosine arabinoside, and methotrexate (BVAM) followed by whole-brain irradiation (WBRT) for patients with primary central nervous system lymphoma (PCNSL). Methods and Materials: Patients 70 years old and younger with newly diagnosed, biopsy-proven PCNSL received one cycle of CHOD followed by two cycles of BVAM. Patients then received WBRT, 30.6 Gy, if a complete response was evoked, or 50.4 Gy if the response was less than complete; both doses were given in 1.8-Gy daily fractions. The primary efficacy endpoint was 1-year survival. Results: Thirty-six patients (19 men, 17 women) enrolled between 1995 and 2000. Median age was 60.5 years (range, 34 to 69 years). Thirty (83%) patients had baseline Eastern Cooperative Oncology Group performance scores of 0 to 1. All 36 patients were eligible for survival and response evaluations. Median time to progression was 12.3 months, and median survival was 18.5 months. The percentages of patients alive at 1, 2, and 3 years were 64%, 36%, and 33%, respectively. The best response was complete response in 10 patients and immediate progression in 7 patients. Ten (28%) patients had at least one grade 3 or higher neurologic toxicity. Conclusions: This regimen did improve the survival of PCNSL patients but also caused substantial toxicity. The improvement in survival is less than that reported with high-dose methotrexate-based therapies.

  6. Bystander effects and radiotherapy.

    PubMed

    Marín, Alicia; Martín, Margarita; Liñán, Olga; Alvarenga, Felipe; López, Mario; Fernández, Laura; Büchser, David; Cerezo, Laura

    2015-01-01

    Radiation-induced bystander effects are defined as biological effects expressed after irradiation by cells whose nuclei have not been directly irradiated. These effects include DNA damage, chromosomal instability, mutation, and apoptosis. There is considerable evidence that ionizing radiation affects cells located near the site of irradiation, which respond individually and collectively as part of a large interconnected web. These bystander signals can alter the dynamic equilibrium between proliferation, apoptosis, quiescence or differentiation. The aim of this review is to examine the most important biological effects of this phenomenon with regard to areas of major interest in radiotherapy. Such aspects include radiation-induced bystander effects during the cell cycle under hypoxic conditions when administering fractionated modalities or combined radio-chemotherapy. Other relevant aspects include individual variation and genetics in toxicity of bystander factors and normal tissue collateral damage. In advanced radiotherapy techniques, such as intensity-modulated radiation therapy (IMRT), the high degree of dose conformity to the target volume reduces the dose and, therefore, the risk of complications, to normal tissues. However, significant doses can accumulate out-of-field due to photon scattering and this may impact cellular response in these regions. Protons may offer a solution to reduce out-of-field doses. The bystander effect has numerous associated phenomena, including adaptive response, genomic instability, and abscopal effects. Also, the bystander effect can influence radiation protection and oxidative stress. It is essential that we understand the mechanisms underlying the bystander effect in order to more accurately assess radiation risk and to evaluate protocols for cancer radiotherapy.

  7. Bystander effects and radiotherapy

    PubMed Central

    Marín, Alicia; Martín, Margarita; Liñán, Olga; Alvarenga, Felipe; López, Mario; Fernández, Laura; Büchser, David; Cerezo, Laura

    2014-01-01

    Radiation-induced bystander effects are defined as biological effects expressed after irradiation by cells whose nuclei have not been directly irradiated. These effects include DNA damage, chromosomal instability, mutation, and apoptosis. There is considerable evidence that ionizing radiation affects cells located near the site of irradiation, which respond individually and collectively as part of a large interconnected web. These bystander signals can alter the dynamic equilibrium between proliferation, apoptosis, quiescence or differentiation. The aim of this review is to examine the most important biological effects of this phenomenon with regard to areas of major interest in radiotherapy. Such aspects include radiation-induced bystander effects during the cell cycle under hypoxic conditions when administering fractionated modalities or combined radio-chemotherapy. Other relevant aspects include individual variation and genetics in toxicity of bystander factors and normal tissue collateral damage. In advanced radiotherapy techniques, such as intensity-modulated radiation therapy (IMRT), the high degree of dose conformity to the target volume reduces the dose and, therefore, the risk of complications, to normal tissues. However, significant doses can accumulate out-of-field due to photon scattering and this may impact cellular response in these regions. Protons may offer a solution to reduce out-of-field doses. The bystander effect has numerous associated phenomena, including adaptive response, genomic instability, and abscopal effects. Also, the bystander effect can influence radiation protection and oxidative stress. It is essential that we understand the mechanisms underlying the bystander effect in order to more accurately assess radiation risk and to evaluate protocols for cancer radiotherapy. PMID:25535579

  8. [Radiotherapy during pregnancy].

    PubMed

    Mazeron, R; Barillot, I; Mornex, F; Giraud, P

    2016-09-01

    The diagnostic of cancer during pregnancy is a rare and delicate situation. As the developments of the embryo and the human fetus are extremely sensitive to ionizing radiations, the treatment of these tumors should be discussed. The studies - preclinical and clinical - based mostly on exposure accidents show that subdiaphragmatic treatments are possible during pregnancy. When radiotherapy is used, phantom estimations of the dose to the fetus, confirmed by in vivo measurements are required. Irradiation and imaging techniques should be arranged to decrease as much as possible the dose delivered to the fetus and hold below the threshold of 0.1Gy.

  9. SU-E-T-545: A MLC-Equipped Robotic Radiosurgery-Radiotherapy Combined System in Treating Hepatic Lesions: Delivery Efficiency as Compared to a Standard Linac for Treating Hepatic Lesions

    SciTech Connect

    Jin, L; Price, R; Wang, L; Meyer, J; Ma, C; Fan, J

    2014-06-01

    Purpose: The CyberKnife (CK) M6 Series introduced a mulitleaf collimator (MLC) beam for extending its capability to the conventional radiotherapy. This work is to investigate delivery efficiency of this system as compared to a standard Varian linac when treating hepatic lesions. Methods: Nine previously treated patients were divided into three groups with three patients in each. Group one: fractionated radiotherapy; Group two: SBRT-like treatments and Group three: fractionated radiotherapy targeting two PTVs. The clinically used plans were generated with the Eclipse treatment planning system (TPS). We re-planned these cases using a Mulitplan (MP) TPS for the CK M6 and normalized to the same PTV dose coverage. CK factors (CF) (defined as modulation scaling factor in this work), number of nodes (NN), number of MLC segments (NS) and beam delivery time (BT) with an estimated image interval of 60 seconds, were used for evaluation of delivery efficiency. Results: Generated plans from the MP and Eclipse TPS demonstrated the similar quality in terms of PTV confomality index, minimum and maximum PTV doses, and doses received by critical structures. Group one: CF ranged from 8.1 to 8.7, NN from 30 to 40, NS from 120 to 155 and BT from 20 to 23 minutes; group two: CF from 4.7 to 8.5, NN from 15 to 19, NS from 82 to 141 and BT from 18 to 24 minutes; and group three: CF from 7.9 to 10, NN from 47 to 49, NS from 110 to 113 and BT from 20 to 22 minutes. Conclusions: Delivery time is longer for the CK M6 than for the Varian linac (7.8 to 13.7 minutes). Further investigation will be necessary to determine if a PTV reduction from the tracking feature will shorten the delivery time without decreasing plan quality.

  10. [Hodgkin's lymphoma and radiotherapy].

    PubMed

    Datsenko, P V; Panshin, G A

    2015-01-01

    After a median observation time of 4,5 years, 440 patients with Hodgkin's lymphoma stage I-IV to the Ann Arbor classification were treated with radiotherapy (2200 lymph areas) and ABVD (n=204) or BEACOPP (n=117) or CEA/ABVD (lomustine, etoposide, adriamycine, bleomycine, vinblastine and dacarbacine; n=119) regimens in 1995-2012. Correct allocation of groups with "CR or PR ≥80%" and "PR: 0-79%", after first-line chemotherapy, is extremely important for following RT planning. Adaptation of patients with Hodgkin's lymphoma can take place only after successful treatment, the probability of relapse and fear of repeated courses strongly interfere with this process, especially in the first years after its closure. Duration of remission period, especially in young people, is no less important than the criteria for overall survival. It is impossible to build recommendations for treatment for Hodgkin's lymphoma, based only on long-term survival rates. Importance of radiotherapy in reducing the number of relapses is undeniable, so the idea that the development of the role of chemotherapy in the treatment of the ray method Hodgkin's lymphoma gradually becomes secondary is in serious doubt. Our findings suggest the importance of both maintaining a high disease-free survival and reducing long-term complications in designing treatments of Hodgkin's lymphoma.

  11. Fertility impairment in radiotherapy

    PubMed Central

    Kuźba-Kryszak, Tamara; Nowikiewicz, Tomasz; Żyromska, Agnieszka

    2016-01-01

    Infertility as a result of antineoplastic therapy is becoming a very important issue due to the growing incidence of neoplastic diseases. Routinely applied antineoplastic treatments and the illness itself lead to fertility disorders. Therapeutic methods used in antineoplastic treatment may cause fertility impairment or sterilization due to permanent damage to reproductive cells. The risk of sterilization depends on the patient's sex, age during therapy, type of neoplasm, radiation dose and treatment area. It is known that chemotherapy and radiotherapy can lead to fertility impairment and the combination of these two gives an additive effect. The aim of this article is to raise the issue of infertility in these patients. It is of growing importance due to the increase in the number of children and young adults who underwent radiotherapy in the past. The progress in antineoplastic therapy improves treatment results, but at the same time requires a deeper look at existential needs of the patient. Reproductive function is an integral element of self-esteem and should be taken into account during therapy planning. PMID:27647982

  12. Imaging in radiotherapy

    NASA Astrophysics Data System (ADS)

    Calandrino, R.; Del Maschio, A.; Cattaneo, G. M.; Castiglioni, I.

    2009-09-01

    The diagnostic methodologies used for the radiotherapy planning have undergone great developments in the last 30 years. Since the 1980s, after the introduction of the CT scanner, the modality for the planning moved beyond the planar 2D assessment to approach a real and more realistic volumetric 3D definition. Consequently the dose distribution, previously obtained by means of an overly simple approximation, became increasingly complex, better tailoring the true shape of the tumour. The final therapeutic improvement has been obtained by a parallel increase in the complexity of the irradiating units: the Linacs for therapy have, in fact, been equipped with a full accessory set capable to modulate the fluence (IMRT) and to check the correct target position continuously during the therapy session (IMRT-IGRT). The multimodal diagnostic approach, which integrates diagnostic information, from images of the patient taken with CT, NMR, PET and US, further improves the data for a biological and topological optimization of the radiotherapy plan and consequently of the dose distribution in the Planning Target Volume. Proteomic and genomic analysis will be the next step in tumour diagnosis. These methods will provide the planners with further information, for a true personalization of the treatment regimen and the assessment of the predictive essays for each tumour and each patient.

  13. [Stereotactic radiosurgery and radiotherapy for brain metastases].

    PubMed

    Tanguy, Ronan; Métellus, Philippe; Mornex, Françoise; Mazeron, Jean-Jacques

    2013-01-01

    Brain metastases management is still controversial even though many trials are trying to define the respective roles of neurosurgery, whole-brain radiotherapy, single-dose stereotactic radiotherapy and fractionated stereotactic radiotherapy. In this article, we review data from trials that examine the role of radiosurgery and fractionated stereotactic radiotherapy in the management of brain metastases.

  14. Intraoperative radiotherapy for breast cancer.

    PubMed

    Vaidya, Jayant S; Tobias, Jeffrey S; Baum, Michael; Keshtgar, Mohammed; Joseph, David; Wenz, Frederik; Houghton, Joan; Saunders, Christobel; Corica, Tammy; D'Souza, Derek; Sainsbury, Richard; Massarut, Samuele; Taylor, Irving; Hilaris, Basil

    2004-03-01

    Postoperative radiotherapy, which forms part of breast-conserving therapy, may not need to encompass the whole breast. Apart from the consumption of huge resources and patients' time, postoperative radiotherapy deters many women from receiving the benefits of breast-conserving surgery, forcing them to choose a mastectomy instead. If radiotherapy could be given in the operating theatre immediately after surgery, many of these disadvantages could be overcome. One striking fact about local recurrence after breast-conserving surgery is that most occurs in the area of breast immediately next to the primary tumour; this is despite the finding that two-thirds of mastectomy samples have microscopic tumours distributed throughout the breast, even when radiotherapy is omitted. Thus, only the area adjacent to the tumour may need treatment with radiotherapy. On the basis of this premise, clinical scientists have used new technology to administer radiotherapy to the area at greatest risk of local recurrence, with the aim of completing the whole local treatment in one sitting. In this review, we have elaborated on the rationale and different methods of delivery of intraoperative radiotherapy. If this approach is validated by the results of current randomised trials, it could save time, money, and breasts.

  15. Pituitary radiotherapy for Cushing's disease.

    PubMed

    Losa, Marco; Picozzi, Piero; Redaelli, Maria Grazia; Laurenzi, Andrea; Mortini, Pietro

    2010-01-01

    The treatment of choice for Cushing's disease is pituitary surgery. Second-line treatments include repeat pituitary surgery, radiation therapy, medical therapy, and bilateral adrenalectomy. The most used modalities to irradiate patients with Cushing's disease include fractionated radiotherapy and single-dose Gamma Knife. We aim to review the efficacy and safety of radiotherapy in patients with persistent or recurring Cushing's disease. Remission of Cushing's disease after radiotherapy ranges from 42 to 83%. There seems to be no clear difference according to the technique of radiation used. Most patients experience remission of disease within 3 years from treatment, with only few cases reaching normal cortisol secretion after a longer follow-up. Control of tumor growth varies from 93 to 100%. Severe side effects of radiotherapy, such as optic neuropathy and radionecrosis, are uncommon. New-onset hypopituitarism is the most frequent side effect of radiation, occurring in 30-50% of patients treated by fractionated radiotherapy while it has been reported in 11-22% of patients after Gamma Knife. Radiotherapy is an effective second-line treatment in patients with Cushing's disease not cured by surgery. Consideration of the advantages and disadvantages of radiotherapy in comparison with other therapeutic options should always be carried out in the single patient before deciding the second-line therapeutic strategy for persisting or recurring Cushing's disease. Copyright © 2010 S. Karger AG, Basel.

  16. [Radiotherapy and targeted therapy/immunotherapy].

    PubMed

    Antoni, D; Bockel, S; Deutsch, E; Mornex, F

    2016-10-01

    Thanks to recent advances achieved in oncologic systemic and local ablative treatment, the treatments become more and more efficient in term of local control and overall survival. Thus, the targeted therapies, immunotherapy or stereotactic radiotherapy have modified the management of patients, especially in case of oligometastatic disease. Many questions are raised by these innovations, particularly the diagnosis and management of new side effects or that of the combination of these different treatments, depending on the type of primary tumor. Fundamental data are available, while clinical data are still limited. Ongoing trials should help to clarify the clinical management protocols. This manuscript is a review of the combination of radiotherapy and targeted therapy/immunotherapy.

  17. Complement is a central mediator of radiotherapy-induced tumor-specific immunity and clinical response.

    PubMed

    Surace, Laura; Lysenko, Veronika; Fontana, Andrea Orlando; Cecconi, Virginia; Janssen, Hans; Bicvic, Antonela; Okoniewski, Michal; Pruschy, Martin; Dummer, Reinhard; Neefjes, Jacques; Knuth, Alexander; Gupta, Anurag; van den Broek, Maries

    2015-04-21

    Radiotherapy induces DNA damage and cell death, but recent data suggest that concomitant immune stimulation is an integral part of the therapeutic action of ionizing radiation. It is poorly understood how radiotherapy supports tumor-specific immunity. Here we report that radiotherapy induced tumor cell death and transiently activated complement both in murine and human tumors. The local production of pro-inflammatory anaphylatoxins C3a and C5a was crucial to the tumor response to radiotherapy and concomitant stimulation of tumor-specific immunity. Dexamethasone, a drug frequently given during radiotherapy, limited complement activation and the anti-tumor effects of the immune system. Overall, our findings indicate that anaphylatoxins are key players in radiotherapy-induced tumor-specific immunity and the ensuing clinical responses.

  18. Monte Carlo role in radiobiological modelling of radiotherapy outcomes

    NASA Astrophysics Data System (ADS)

    El Naqa, Issam; Pater, Piotr; Seuntjens, Jan

    2012-06-01

    Radiobiological models are essential components of modern radiotherapy. They are increasingly applied to optimize and evaluate the quality of different treatment planning modalities. They are frequently used in designing new radiotherapy clinical trials by estimating the expected therapeutic ratio of new protocols. In radiobiology, the therapeutic ratio is estimated from the expected gain in tumour control probability (TCP) to the risk of normal tissue complication probability (NTCP). However, estimates of TCP/NTCP are currently based on the deterministic and simplistic linear-quadratic formalism with limited prediction power when applied prospectively. Given the complex and stochastic nature of the physical, chemical and biological interactions associated with spatial and temporal radiation induced effects in living tissues, it is conjectured that methods based on Monte Carlo (MC) analysis may provide better estimates of TCP/NTCP for radiotherapy treatment planning and trial design. Indeed, over the past few decades, methods based on MC have demonstrated superior performance for accurate simulation of radiation transport, tumour growth and particle track structures; however, successful application of modelling radiobiological response and outcomes in radiotherapy is still hampered with several challenges. In this review, we provide an overview of some of the main techniques used in radiobiological modelling for radiotherapy, with focus on the MC role as a promising computational vehicle. We highlight the current challenges, issues and future potentials of the MC approach towards a comprehensive systems-based framework in radiobiological modelling for radiotherapy.

  19. Image-guided radiotherapy: from current concept to future perspectives.

    PubMed

    Jaffray, David A

    2012-12-01

    Radiotherapy is a highly effective, targeted therapy for the management of cancer. Technological innovations have enabled the direct integration of imaging technology into the radiation treatment device to increase the precision and accuracy of radiation delivery. As well as addressing a clinical need to better control the placement of the dose within the body, image-guided radiotherapy has enabled innovators in the field to accelerate their exploration of a number of different paradigms of radiation delivery, including toxicity reduction, dose escalation, hypofractionation, voxelization, and adaptation. Although these approaches are already innovative trends in radiation oncology, it is anticipated that they will work synergistically with other innovations in cancer management (including biomarker strategies, novel systemic and local therapies) as part of the broader goal of personalized cancer medicine. This Review discusses the rationale for adopting image-guidance approaches in radiotherapy, and the technology for achieving precision and accuracy in the context of different paradigms within the evolving radiation oncology practice. It also examines exciting advances in radiotherapy technology that suggest a convergence of radiotherapy practice in which patient-specific radiotherapy treatment courses are one of the most personalized forms of intervention in cancer medicine.

  20. Radiotherapy in Phyllodes Tumour

    PubMed Central

    Sasidharan, Balukrishna; Manipadam, Marie Therese; Paul, M J; Backianathan, Selvamani

    2017-01-01

    Introduction Phyllodes Tumour (PT) of the breast is a relatively rare breast neoplasm (<1%) with diverse range of pathology and biological behaviour. Aim To describe the clinical course of PT and to define the role of Radiotherapy (RT) in PT of the breast. Materials and Methods Retrospective analysis of hospital data of patients with PT presented from 2005 to 2014 was done. Descriptive statistics was used to analyze the results. Simple description of data was done in this study. Age and duration of symptoms were expressed in median and range. Percentages, tables and general discussions were used to understand the meaning of the data analyzed. Results Out of the 98 patients, 92 were eligible for analysis. The median age of presentation was 43 years. A total of 64/92 patients were premenopausal. There was no side predilection for this tumour but 57/92 patients presented as an upper outer quadrant lump. Fifty percent of the patients presented as giant (10 cm) PT. The median duration of symptoms was 12 months (range: 1-168 months). A 60% of patients had Benign (B), 23% had Borderline (BL) and 17% had malignant (M) tumours. The surgical treatment for benign histology included Lumpectomy (L) for 15%, Wide Local Excision (WLE) for 48%, and Simple Mastectomy (SM) for 37%. All BL and M tumours were treated with WLE or SM. There was no recurrence in B and BL group when the margin was ≥1 cm. All non-metastatic M tumours received adjuvant RT irrespective of their margin status. Total 3/16 patients with M developed local recurrence. Total 6/16 M patients had distant metastases (lung or bone). Our median duration of follow up was 20 months (range: 1-120 months). Conclusion Surgical resection with adequate margins (>1 cm) gave excellent local control in B and BL tumours. For patients with BL PT, local radiotherapy is useful, if margins are close or positive even after the best surgical resection. There is a trend towards improved local control with adjuvant radiotherapy for

  1. Current concepts on imaging in radiotherapy.

    PubMed

    Lecchi, Michela; Fossati, Piero; Elisei, Federica; Orecchia, Roberto; Lucignani, Giovanni

    2008-04-01

    New high-precision radiotherapy (RT) techniques, such as intensity-modulated radiation therapy (IMRT) or hadrontherapy, allow better dose distribution within the target and spare a larger portion of normal tissue than conventional RT. These techniques require accurate tumour volume delineation and intrinsic characterization, as well as verification of target localisation and monitoring of organ motion and response assessment during treatment. These tasks are strongly dependent on imaging technologies. Among these, computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography (US) and positron emission tomography (PET) have been applied in high-precision RT. For tumour volume delineation and characterization, PET has brought an additional dimension to the management of cancer patients by allowing the incorporation of crucial functional and molecular images in RT treatment planning, i.e. direct evaluation of tumour metabolism, cell proliferation, apoptosis, hypoxia and angiogenesis. The combination of PET and CT in a single imaging system (PET/CT) to obtain a fused anatomical and functional dataset is now emerging as a promising tool in radiotherapy departments for delineation of tumour volumes and optimization of treatment plans. Another exciting new area is image-guided radiotherapy (IGRT), which focuses on the potential benefit of advanced imaging and image registration to improve precision, daily target localization and monitoring during treatment, thus reducing morbidity and potentially allowing the safe delivery of higher doses. The variety of IGRT systems is rapidly expanding, including cone beam CT and US. This article examines the increasing role of imaging techniques in the entire process of high-precision radiotherapy.

  2. Dynamic targeting image-guided radiotherapy

    SciTech Connect

    Huntzinger, Calvin; Munro, Peter; Johnson, Scott; Miettinen, Mika; Zankowski, Corey; Ahlstrom, Greg; Glettig, Reto; Filliberti, Reto; Kaissl, Wolfgang; Kamber, Martin; Amstutz, Martin; Bouchet, Lionel; Klebanov, Dan; Mostafavi, Hassan; Stark, Richard

    2006-07-01

    Volumetric imaging and planning for 3-dimensional (3D) conformal radiotherapy and intensity-modulated radiotherapy (IMRT) have highlighted the need to the oncology community to better understand the geometric uncertainties inherent in the radiotherapy delivery process, including setup error (interfraction) as well as organ motion during treatment (intrafraction). This has ushered in the development of emerging technologies and clinical processes, collectively referred to as image-guided radiotherapy (IGRT). The goal of IGRT is to provide the tools needed to manage both inter- and intrafraction motion to improve the accuracy of treatment delivery. Like IMRT, IGRT is a process involving all steps in the radiotherapy treatment process, including patient immobilization, computed tomogaphy (CT) simulation, treatment planning, plan verification, patient setup verification and correction, delivery, and quality assurance. The technology and capability of the Dynamic Targeting{sup TM} IGRT system developed by Varian Medical Systems is presented. The core of this system is a Clinac (registered) or Trilogy{sup TM} accelerator equipped with a gantry-mounted imaging system known as the On-Board Imager{sup TM} (OBI). This includes a kilovoltage (kV) x-ray source, an amorphous silicon kV digital image detector, and 2 robotic arms that independently position the kV source and imager orthogonal to the treatment beam. A similar robotic arm positions the PortalVision{sup TM} megavoltage (MV) portal digital image detector, allowing both to be used in concert. The system is designed to support a variety of imaging modalities. The following applications and how they fit in the overall clinical process are described: kV and MV planar radiographic imaging for patient repositioning, kV volumetric cone beam CT imaging for patient repositioning, and kV planar fluoroscopic imaging for gating verification. Achieving image-guided motion management throughout the radiation oncology process

  3. [Respiratory synchronization and breast radiotherapy].

    PubMed

    Mège, A; Ziouèche-Mottet, A; Bodez, V; Garcia, R; Arnaud, A; de Rauglaudre, G; Pourel, N; Chauvet, B

    2016-10-01

    Adjuvant radiation therapy following breast cancer surgery continues to improve locoregional control and overall survival. But the success of highly targeted-conformal radiotherapy such as intensity-modulated techniques, can be compromised by respiratory motion. The intrafraction motion can potentially result in significant under- or overdose, and also expose organs at risk. This article summarizes the respiratory motion and its effects on imaging, dose calculation and dose delivery by radiotherapy for breast cancer. We will review the methods of respiratory synchronization available for breast radiotherapy to minimize the respiratory impact and to spare organs such as heart and lung.

  4. [Hepatic tumors and radiotherapy].

    PubMed

    Rio, E; Mornex, F; Peiffert, D; Huertas, A

    2016-09-01

    Recent technological developments led to develop the concept of focused liver radiation therapy. We must distinguish primary and secondary tumors as the indications are restricted and must be discussed as an alternative to surgical or medical treatments. For hepatocellular carcinoma 5 to 10cm (or more), a conformational radiation with or without intensity modulation is performed. Stereotactic body radiotherapy (SBRT) is being evaluated and is increasingly proposed as an alternative to radiofrequency ablative treatment for primary or secondary tumors (typically less than 5cm). Tumor (and liver) movements induced by respiratory motions must be taken into account. Strict dosimetric criteria must be met with particular attention to the dose-volume histograms to liver and the hollow organs, including cases of SBRT.

  5. [Radiotherapy for nasopharyngeal carcinoma].

    PubMed

    Maingon, P; Blanchard, P; Bidault, F; Calmels, L

    2016-09-01

    Nasapharyngeal carcinoma is a rare disease. Oftenly, the diagnostic is made for advanced disease. Localized tumors, T1 or T2 NO observed a good prognosis and are locally controlled in more than 90 % of the cases by radiotherapy alone. The standard treatment of locally advanced disease is combined chemoradiation. A special vigilance of fast decrease of the volume of the pathological lymph nodes, sometimes associated to loss of weight might indicate an adaptive dosimetric revision. The treatment of recurrent disease is of great importance. Surgical indications are limited but should be discussed in multidisciplinary tumor board when possible. Surgical nodal sampling has to be proposed for nodal recurrence as well as reirradiation, which could be indicated according to the technical issues.

  6. Radiotherapy Planning using MRI

    PubMed Central

    Schmidt, Maria A; Payne, Geoffrey S

    2016-01-01

    The use of Magnetic Resonance Imaging (MRI) in Radiotherapy (RT) planning is rapidly expanding. We review the wide range of image contrast mechanisms available to MRI and the way they are exploited for RT planning. However a number of challenges are also considered: the requirements that MR images are acquired in the RT treatment position, that they are geometrically accurate, that effects of patient motion during the scan are minimised, that tissue markers are clearly demonstrated, that an estimate of electron density can be obtained. These issues are discussed in detail, prior to the consideration of a number of specific clinical applications. This is followed by a brief discussion on the development of real-time MRI-guided RT. PMID:26509844

  7. Radiotherapy on hidradenocarcinoma

    PubMed Central

    Lalya, Issam; Hadadi, Khalid; Tazi, El Mehdi; Lalya, Ilham; Bazine, Amine; Andaloussy, Khalid; Elmarjany, Mohamed; Sifat, Hassan; Hassouni, Khalid; Kebdani, Tayeb; Mansouri, Hamid; Benjaafar, Noureddine; Elgueddari, Brahim Khalil

    2011-01-01

    Context: Clear cell Hidradenocarcinoma is a rare carcinoma arising from sweat glands. It is an aggressive tumor that most metastasizes to regional lymph nodes and distant viscera; surgery with safe margins is the mainstay of treatment. Case Report: We report a case of 68-year-old woman who presented with an invasive clear cell hidradenocarcinoma situated in the left parotid area which recurred 5 months after surgery, this recurrence was managed successfully by high-dose irradiation of the tumor bed (66 Gy) and regional lymphatic chains (50 Gy), after a follow-up of more than 15 months, the patient is in good local control without significant toxicity. Conclusion: Post operative radiotherapy allows better local control and should be mandatory when histological features predictive of recurrence are present: positive margins, histology poorly differentiated, perineural invasion, vascular and lymphatic invasion, lymph node involvement, and extracapsular spread. PMID:22540063

  8. Pion radiotherapy at LAMPF

    SciTech Connect

    Bush, S.E.; Smith, A.R.; Zink, S.

    1982-12-01

    Clinical investigations of pi meson radiotherapy were conducted by the Cancer Research and Treatment Center of the University of New Mexico and the Los Alamos National Laboratory from 1974 until 1982. Two hundred and thirty patients have been treated for a variety of locally advanced primary and metastatic neoplasms. One hundred and ninety-six patients have been followed for a minimum of 18 months. Crude survival data range from 11% for unresectable pancreatic carcinoma to 82% for Stages C and D1 adenocarcinoma of the prostate. Acute tolerance of normal tissues is approximately 4500 pion rad in 36 fractions over 7 weeks. Severe chronic reactions have appeared with increasing frequency after doses in excess of 4000 pion rad.

  9. Hepatic arterial infusion chemotherapy using 5-fluorouracil and systemic interferon-α for advanced hepatocellular carcinoma in combination with or without three-dimensional conformal radiotherapy to venous tumor thrombosis in hepatic vein or inferior vena cava.

    PubMed

    Murakami, Eisuke; Aikata, Hiroshi; Miyaki, Daisuke; Nagaoki, Yuko; Katamura, Yoshio; Kawaoka, Tomokazu; Takaki, Shintaro; Hiramatsu, Akira; Waki, Koji; Takahashi, Shoichi; Kimura, Tomoki; Kenjo, Masahiro; Nagata, Yasushi; Ishikawa, Masaki; Kakizawa, Hideaki; Awai, Kazuo; Chayama, Kazuaki

    2012-05-01

      We investigated the efficacy of hepatic arterial infusion chemotherapy (HAIC) using 5-fluorouracil (5-FU) and systemic interferon (IFN)-α (HAIC-5-FU/IFN) for advanced hepatocellular carcinoma (HCC) with venous tumor thrombosis (VTT) in the hepatic vein trunk (Vv2) or inferior vena cava (Vv3).   Thirty-three patients with HCC/Vv2/3 underwent HAIC with 5-FU (500 mg/body weight/day, into hepatic artery on days 1-5 on the first and second weeks) and IFN-α (recombinant IFN-α-2b 3 000 000 U or natural IFN-α 5 000 000 U, intramuscularly on days 1, 3 and 5 of each week). Three-dimensional conformal radiotherapy (3D-CRT) was used in combination with HAIC-5-FU/IFN in 14 of 33 patients to reduce VTT.   The median survival time (MST) was 7.9 months, and 1- and 2-year survival rates were 30% and 20%, respectively. Evaluation of intrahepatic response after two cycles of HAIC-5-FU/IFN showed complete response (CR) in three (9%) and partial response (PR) in seven (21%), with an objective response rate of 30%. Multivariate analysis identified reduction of VTT (P = 0.0006), size of largest tumor (P = 0.013) and intrahepatic response CR/PR (P = 0.030) as determinants of survival. CR/PR correlated significantly with tumor liver occupying rate (P = 0.016) and hepatitis C virus Ab (P = 0.010). Reduction of VTT correlated significantly with radiotherapy (P = 0.021) and platelet count (P = 0.015). Radiotherapy-related reduction in VTT significantly improved survival of 16 patients with Vv3 and non-CR/PR response of HAIC-5-FU/IFN (P = 0.028).   As for advanced HCC with VTT of Vv2/3, HAIC-5-FU/IFN responsive patients could obtain favorable survival. Despite ineffective HAIC-5-FU/IFN, the combination with effective radiotherapy to VTT might improve patients' prognosis. © 2011 The Japan Society of Hepatology.

  10. Fiber optically coupled radioluminescence detectors: A short review of key strengths and weaknesses of BCF-60 and Al2O3:C scintillating-material based systems in radiotherapy dosimetry applications

    NASA Astrophysics Data System (ADS)

    Buranurak, S.; Andersen, C. E.

    2017-06-01

    Radiotherapy technologies have improved for several decades aiming to effectively destroy cancerous tissues without overdosing surrounding healthy tissues. In order to fulfil this requirement, accurate and precise dosimetry systems play an important role. Throughout the years, ionization chambers have been used as a standard detector for basic linear accelerator calibrations and reference dosimetry in hospitals. However, they are not ideal for all treatment modalities: and limitations and difficulties have been reported in case of (i) small treatment fields, (ii) strong magnetic field used in the new hybrid MRI LINAC/cobalt systems, and (iii) in vivo measurements due to safety-issues related to the high operating voltage. Fiber optically coupled luminescence detectors provide a promising supplement to ionization chambers by offering the capability of real-time in vivo dose monitoring with high time resolution. In particular, the all-optical nature of these detectors is an advantage for in vivo measurements due to the absence of high voltage supply or electrical wire that could cause harm to the patient or disturb the treatment. Basically, fiber-coupled luminescence detector systems function by radiation-induced generation of radioluminescence from a sub-mm size organic/inorganic phosphor. A thin optical fiber cable is used for guiding the radioluminescence to a photomultiplier tube or similar sensitive light detection systems. The measured light intensity is proportional to dose rate. Throughout the years, developments and research of the fiber detector systems have undergone in several groups worldwide. In this article, the in-house developed fiber detector systems based on two luminescence phosphors of (i) BCF-60 polystyrene-based organic plastic scintillator and (ii) carbon-doped aluminum oxide crystal (Al2O3:C) are reviewed with comparison to the same material-based systems reported in the literature. The potential use of these detectors for reference

  11. Personalized radiotherapy: concepts, biomarkers and trial design.

    PubMed

    Ree, A H; Redalen, K R

    2015-07-01

    In the past decade, and pointing onwards to the immediate future, clinical radiotherapy has undergone considerable developments, essentially including technological advances to sculpt radiation delivery, the demonstration of the benefit of adding concomitant cytotoxic agents to radiotherapy for a range of tumour types and, intriguingly, the increasing integration of targeted therapeutics for biological optimization of radiation effects. Recent molecular and imaging insights into radiobiology will provide a unique opportunity for rational patient treatment, enabling the parallel design of next-generation trials that formally examine the therapeutic outcome of adding targeted drugs to radiation, together with the critically important assessment of radiation volume and dose-limiting treatment toxicities. In considering the use of systemic agents with presumed radiosensitizing activity, this may also include the identification of molecular, metabolic and imaging markers of treatment response and tolerability, and will need particular attention on patient eligibility. In addition to providing an overview of clinical biomarker studies relevant for personalized radiotherapy, this communication will highlight principles in addressing clinical evaluation of combined-modality-targeted therapeutics and radiation. The increasing number of translational studies that bridge large-scale omics sciences with quality-assured phenomics end points-given the imperative development of open-source data repositories to allow investigators the access to the complex data sets-will enable radiation oncology to continue to position itself with the highest level of evidence within existing clinical practice.

  12. Personalized radiotherapy: concepts, biomarkers and trial design

    PubMed Central

    Redalen, K R

    2015-01-01

    In the past decade, and pointing onwards to the immediate future, clinical radiotherapy has undergone considerable developments, essentially including technological advances to sculpt radiation delivery, the demonstration of the benefit of adding concomitant cytotoxic agents to radiotherapy for a range of tumour types and, intriguingly, the increasing integration of targeted therapeutics for biological optimization of radiation effects. Recent molecular and imaging insights into radiobiology will provide a unique opportunity for rational patient treatment, enabling the parallel design of next-generation trials that formally examine the therapeutic outcome of adding targeted drugs to radiation, together with the critically important assessment of radiation volume and dose-limiting treatment toxicities. In considering the use of systemic agents with presumed radiosensitizing activity, this may also include the identification of molecular, metabolic and imaging markers of treatment response and tolerability, and will need particular attention on patient eligibility. In addition to providing an overview of clinical biomarker studies relevant for personalized radiotherapy, this communication will highlight principles in addressing clinical evaluation of combined-modality-targeted therapeutics and radiation. The increasing number of translational studies that bridge large-scale omics sciences with quality-assured phenomics end points—given the imperative development of open-source data repositories to allow investigators the access to the complex data sets—will enable radiation oncology to continue to position itself with the highest level of evidence within existing clinical practice. PMID:25989697

  13. Big Data Analytics for Prostate Radiotherapy.

    PubMed

    Coates, James; Souhami, Luis; El Naqa, Issam

    2016-01-01

    Radiation therapy is a first-line treatment option for localized prostate cancer and radiation-induced normal tissue damage are often the main limiting factor for modern radiotherapy regimens. Conversely, under-dosing of target volumes in an attempt to spare adjacent healthy tissues limits the likelihood of achieving local, long-term control. Thus, the ability to generate personalized data-driven risk profiles for radiotherapy outcomes would provide valuable prognostic information to help guide both clinicians and patients alike. Big data applied to radiation oncology promises to deliver better understanding of outcomes by harvesting and integrating heterogeneous data types, including patient-specific clinical parameters, treatment-related dose-volume metrics, and biological risk factors. When taken together, such variables make up the basis for a multi-dimensional space (the "RadoncSpace") in which the presented modeling techniques search in order to identify significant predictors. Herein, we review outcome modeling and big data-mining techniques for both tumor control and radiotherapy-induced normal tissue effects. We apply many of the presented modeling approaches onto a cohort of hypofractionated prostate cancer patients taking into account different data types and a large heterogeneous mix of physical and biological parameters. Cross-validation techniques are also reviewed for the refinement of the proposed framework architecture and checking individual model performance. We conclude by considering advanced modeling techniques that borrow concepts from big data analytics, such as machine learning and artificial intelligence, before discussing the potential future impact of systems radiobiology approaches.

  14. Bone Health and Pelvic Radiotherapy.

    PubMed

    Higham, C E; Faithfull, S

    2015-11-01

    Survivors who have received pelvic radiotherapy make up many of the long-term cancer population, with therapies for gynaecological, bowel, bladder and prostate malignancies. Individuals who receive radiotherapy to the pelvis as part of their cancer treatment are at risk of insufficiency fractures. Symptoms of insufficiency fractures include pelvic and back pain and immobility, which can affect substantially quality of life. This constellation of symptoms can occur within 2 months of radiotherapy up to 63 months post-treatment, with a median incidence of 6-20 months. As a condition it is under reported and evidence is poor as to the contributing risk factors, causation and best management to improve the patient's bone health and mobility. As radiotherapy advances, chronic symptoms, such as insufficiency fractures, as a consequence of treatment need to be better understood and reviewed. This overview explores the current evidence for the effect of radiotherapy on bone health and insufficiency fractures and identifies what we know and where gaps in our knowledge lie. The overview concludes with the need to take seriously complaints of pelvic pain from patients after pelvic radiotherapy and to investigate and manage these symptoms more effectively. There is a clear need for definitive research in this field to provide the evidence-based guidance much needed in practice.

  15. Translational Research to Improve the Efficacy of Carbon Ion Radiotherapy: Experience of Gunma University

    PubMed Central

    Oike, Takahiro; Sato, Hiro; Noda, Shin-ei; Nakano, Takashi

    2016-01-01

    Carbon ion radiotherapy holds great promise for cancer therapy. Clinical data show that carbon ion radiotherapy is an effective treatment for tumors that are resistant to X-ray radiotherapy. Since 1994 in Japan, the National Institute of Radiological Sciences has been heading the development of carbon ion radiotherapy using the Heavy Ion Medical Accelerator in Chiba. The Gunma University Heavy Ion Medical Center (GHMC) was established in the year 2006 as a proof-of-principle institute for carbon ion radiotherapy with a view to facilitating the worldwide spread of compact accelerator systems. Along with the management of more than 1900 cancer patients to date, GHMC engages in translational research to improve the treatment efficacy of carbon ion radiotherapy. Research aimed at guiding patient selection is of utmost importance for making the most of carbon ion radiotherapy, which is an extremely limited medical resource. Intratumoral oxygen levels, radiation-induced cellular apoptosis, the capacity to repair DNA double-strand breaks, and the mutational status of tumor protein p53 and epidermal growth factor receptor genes are all associated with X-ray sensitivity. Assays for these factors are useful in the identification of X-ray-resistant tumors for which carbon ion radiotherapy would be beneficial. Research aimed at optimizing treatments based on carbon ion radiotherapy is also important. This includes assessment of dose fractionation, normal tissue toxicity, tumor cell motility, and bystander effects. Furthermore, the efficacy of carbon ion radiotherapy will likely be enhanced by research into combined treatment with other modalities such as chemotherapy. Several clinically available chemotherapeutic drugs (carboplatin, paclitaxel, and etoposide) and drugs at the developmental stage (Wee-1 and heat shock protein 90 inhibitors) show a sensitizing effect on tumor cells treated with carbon ions. Additionally, the efficacy of carbon ion radiotherapy can be improved by

  16. Translational Research to Improve the Efficacy of Carbon Ion Radiotherapy: Experience of Gunma University.

    PubMed

    Oike, Takahiro; Sato, Hiro; Noda, Shin-Ei; Nakano, Takashi

    2016-01-01

    Carbon ion radiotherapy holds great promise for cancer therapy. Clinical data show that carbon ion radiotherapy is an effective treatment for tumors that are resistant to X-ray radiotherapy. Since 1994 in Japan, the National Institute of Radiological Sciences has been heading the development of carbon ion radiotherapy using the Heavy Ion Medical Accelerator in Chiba. The Gunma University Heavy Ion Medical Center (GHMC) was established in the year 2006 as a proof-of-principle institute for carbon ion radiotherapy with a view to facilitating the worldwide spread of compact accelerator systems. Along with the management of more than 1900 cancer patients to date, GHMC engages in translational research to improve the treatment efficacy of carbon ion radiotherapy. Research aimed at guiding patient selection is of utmost importance for making the most of carbon ion radiotherapy, which is an extremely limited medical resource. Intratumoral oxygen levels, radiation-induced cellular apoptosis, the capacity to repair DNA double-strand breaks, and the mutational status of tumor protein p53 and epidermal growth factor receptor genes are all associated with X-ray sensitivity. Assays for these factors are useful in the identification of X-ray-resistant tumors for which carbon ion radiotherapy would be beneficial. Research aimed at optimizing treatments based on carbon ion radiotherapy is also important. This includes assessment of dose fractionation, normal tissue toxicity, tumor cell motility, and bystander effects. Furthermore, the efficacy of carbon ion radiotherapy will likely be enhanced by research into combined treatment with other modalities such as chemotherapy. Several clinically available chemotherapeutic drugs (carboplatin, paclitaxel, and etoposide) and drugs at the developmental stage (Wee-1 and heat shock protein 90 inhibitors) show a sensitizing effect on tumor cells treated with carbon ions. Additionally, the efficacy of carbon ion radiotherapy can be improved by

  17. [Integration of the radiotherapy irradiation planning in the digital workflow].

    PubMed

    Röhner, F; Schmucker, M; Henne, K; Momm, F; Bruggmoser, G; Grosu, A-L; Frommhold, H; Heinemann, F E

    2013-02-01

    At the Clinic of Radiotherapy at the University Hospital Freiburg, all relevant workflow is paperless. After implementing the Operating Schedule System (OSS) as a framework, all processes are being implemented into the departmental system MOSAIQ. Designing a digital workflow for radiotherapy irradiation planning is a large challenge, it requires interdisciplinary expertise and therefore the interfaces between the professions also have to be interdisciplinary. For every single step of radiotherapy irradiation planning, distinct responsibilities have to be defined and documented. All aspects of digital storage, backup and long-term availability of data were considered and have already been realized during the OSS project. After an analysis of the complete workflow and the statutory requirements, a detailed project plan was designed. In an interdisciplinary workgroup, problems were discussed and a detailed flowchart was developed. The new functionalities were implemented in a testing environment by the Clinical and Administrative IT Department (CAI). After extensive tests they were integrated into the new modular department system. The Clinic of Radiotherapy succeeded in realizing a completely digital workflow for radiotherapy irradiation planning. During the testing phase, our digital workflow was examined and afterwards was approved by the responsible authority.

  18. Comparison of the dose distribution obtained from dosimetric systems with intensity modulated radiotherapy planning system in the treatment of prostate cancer

    SciTech Connect

    Gökçe, M. Uslu, D. Koçyiğit; Ertunç, C.; Karalı, T.

    2016-03-25

    The aim of this study is to compare Intensity Modulated Radiation Therapy (IMRT) plan of prostate cancer patients with different dose verification systems in dosimetric aspects and to compare these systems with each other in terms of reliability, applicability and application time. Dosimetric control processes of IMRT plan of three prostate cancer patients were carried out using thermoluminescent dosimeter (TLD), ion chamber (IC) and 2D Array detector systems. The difference between the dose values obtained from the dosimetric systems and treatment planning system (TPS) were found to be about % 5. For the measured (TLD) and calculated (TPS) doses %3 percentage differences were obtained for the points close to center while percentage differences increased at the field edges. It was found that TLD and IC measurements will increase the precision and reliability of the results of 2D Array.

  19. Comparison of the dose distribution obtained from dosimetric systems with intensity modulated radiotherapy planning system in the treatment of prostate cancer

    NASA Astrophysics Data System (ADS)

    Gökçe, M.; Uslu, D. Koçyiǧit; Ertunç, C.; Karalı, T.

    2016-03-01

    The aim of this study is to compare Intensity Modulated Radiation Therapy (IMRT) plan of prostate cancer patients with different dose verification systems in dosimetric aspects and to compare these systems with each other in terms of reliability, applicability and application time. Dosimetric control processes of IMRT plan of three prostate cancer patients were carried out using thermoluminescent dosimeter (TLD), ion chamber (IC) and 2D Array detector systems. The difference between the dose values obtained from the dosimetric systems and treatment planning system (TPS) were found to be about % 5. For the measured (TLD) and calculated (TPS) doses %3 percentage differences were obtained for the points close to center while percentage differences increased at the field edges. It was found that TLD and IC measurements will increase the precision and reliability of the results of 2D Array.

  20. Adapting radiotherapy to hypoxic tumours

    NASA Astrophysics Data System (ADS)

    Malinen, Eirik; Søvik, Åste; Hristov, Dimitre; Bruland, Øyvind S.; Rune Olsen, Dag

    2006-10-01

    In the current work, the concepts of biologically adapted radiotherapy of hypoxic tumours in a framework encompassing functional tumour imaging, tumour control predictions, inverse treatment planning and intensity modulated radiotherapy (IMRT) were presented. Dynamic contrast enhanced magnetic resonance imaging (DCEMRI) of a spontaneous sarcoma in the nasal region of a dog was employed. The tracer concentration in the tumour was assumed related to the oxygen tension and compared to Eppendorf histograph measurements. Based on the pO2-related images derived from the MR analysis, the tumour was divided into four compartments by a segmentation procedure. DICOM structure sets for IMRT planning could be derived thereof. In order to display the possible advantages of non-uniform tumour doses, dose redistribution among the four tumour compartments was introduced. The dose redistribution was constrained by keeping the average dose to the tumour equal to a conventional target dose. The compartmental doses yielding optimum tumour control probability (TCP) were used as input in an inverse planning system, where the planning basis was the pO2-related tumour images from the MR analysis. Uniform (conventional) and non-uniform IMRT plans were scored both physically and biologically. The consequences of random and systematic errors in the compartmental images were evaluated. The normalized frequency distributions of the tracer concentration and the pO2 Eppendorf measurements were not significantly different. 28% of the tumour had, according to the MR analysis, pO2 values of less than 5 mm Hg. The optimum TCP following a non-uniform dose prescription was about four times higher than that following a uniform dose prescription. The non-uniform IMRT dose distribution resulting from the inverse planning gave a three times higher TCP than that of the uniform distribution. The TCP and the dose-based plan quality depended on IMRT parameters defined in the inverse planning procedure (fields

  1. Dose factor entry and display tool for BNCT radiotherapy

    DOEpatents

    Wessol, Daniel E.; Wheeler, Floyd J.; Cook, Jeremy L.

    1999-01-01

    A system for use in Boron Neutron Capture Therapy (BNCT) radiotherapy planning where a biological distribution is calculated using a combination of conversion factors and a previously calculated physical distribution. Conversion factors are presented in a graphical spreadsheet so that a planner can easily view and modify the conversion factors. For radiotherapy in multi-component modalities, such as Fast-Neutron and BNCT, it is necessary to combine each conversion factor component to form an effective dose which is used in radiotherapy planning and evaluation. The Dose Factor Entry and Display System is designed to facilitate planner entry of appropriate conversion factors in a straightforward manner for each component. The effective isodose is then immediately computed and displayed over the appropriate background (e.g. digitized image).

  2. [Adaptative radiotherapy: The case for MRI-guided radiotherapy].

    PubMed

    Maingon, P

    2016-10-01

    The concept of image-guided radiotherapy benefits from the development of magnetic resonance imaging (MRI) associated with different capacities of tissue analyses such as spectroscopy or diffusion analysis. The production of devices allowing the repositioning of patients through MRI represents a strong added value without delivering any additional dose to the patient while the optimization of the adaptative strategies are facilitated by a better contrast of the soft tissues compared to the scanner. The advantages of MRI are well demonstrated for brain tumours, head and neck carcinomas, pelvic tumors, mediastinal malignancies, gastrointestinal tract diseases. Adaptative radiotherapy inaugurates a new area of radiotherapy with different modalities. Several technological solutions are provided or discussed allowing the patients to benefit from thses new technologies as soon as possible.

  3. Development of Advanced Multi-Modality Radiation Treatment Planning Software for Neutron Radiotherapy and Beyond

    SciTech Connect

    Nigg, D; Wessol, D; Wemple, C; Harkin, G; Hartmann-Siantar, C

    2002-08-20

    The Idaho National Engineering and Environmental Laboratory (INEEL) has long been active in development of advanced Monte-Carlo based computational dosimetry and treatment planning methods and software for advanced radiotherapy, with a particular focus on Neutron Capture Therapy (NCT) and, to a somewhat lesser extent, Fast-Neutron Therapy. The most recent INEEL software system of this type is known as SERA, Simulation Environment for Radiotherapy Applications. As a logical next step in the development of modern radiotherapy planning tools to support the most advanced research, INEEL and Lawrence Livermore National Laboratory (LLNL), the developers of the PEREGRTNE computational engine for radiotherapy treatment planning applications, have recently launched a new project to collaborate in the development of a ''next-generation'' multi-modality treatment planning software system that will be useful for all modern forms of radiotherapy.

  4. [Postoperative radiotherapy of prostate cancer].

    PubMed

    Guérif, S; Latorzeff, I; Lagrange, J-L; Hennequin, C; Supiot, S; Garcia, A; François, P; Soulié, M; Richaud, P; Salomon, L

    2014-10-01

    Between 10 and 40% of patients who have undergone a radical prostatectomy may have a biologic recurrence. Local or distant failure represents the possible patterns of relapse. Patients at high-risk for local relapse have extraprostatic disease, positive surgical margins or seminal vesicles infiltration or high Gleason score at pathology. Three phase-III randomized clinical trials have shown that, for these patients, adjuvant irradiation reduces the risk of tumoral progression without higher toxicity. Salvage radiotherapy for late relapse allows a disease control in 60-70% of the cases. Several research in order to improve the therapeutic ratio of the radiotherapy after prostatectomy are evaluate in the French Groupe d'Étude des Tumeurs Urogénitales (Gétug) and of the French association of urology (Afu). The Gétug-Afu 17 trial will provide answers to the question of the optimal moment for postoperative radiotherapy for pT3-4 R1 pN0 Nx patients, with the objective of comparing an immediate treatment to a differed early treatment initiated at biological recurrence. The Gétug-Afu 22 questions the place of a short hormonetherapy combined with image-guided, intensity-modulated radiotherapy (IMRT) in adjuvant situation for a detectable prostate specific antigen (PSA). The implementation of a multicenter quality control within the Gétug-Afu in order to harmonize a modern postoperative radiotherapy will allow the development of a dose escalation IMRT after surgery.

  5. EGF-coated gold nanoparticles provide an efficient nano-scale delivery system for the molecular radiotherapy of EGFR-positive cancer

    PubMed Central

    Song, Lei; Falzone, Nadia; Vallis, Katherine A.

    2016-01-01

    Abstract Purpose Radiolabeled antibodies and peptides hold promise for molecular radiotherapy but are often limited by a low payload resulting in inadequate delivery of radioactivity to tumour tissue and, therefore, modest therapeutic effect. We developed a facile synthetic method of radiolabeling indium-111 (111In) to epidermal growth factor (EGF)-gold nanoparticles (111In-EGF-Au NP) with a high payload. Materials and methods EGF-Au NP were prepared via an interaction between gold and the disulphide bonds of EGF and radiolabeled using 111InCl3. Targeting efficiency was investigated by quantitating internalized radioactivity and by confocal imaging following exposure of MDA-MB-468 (1.3 × 106 EGFR/cell) and MCF-7 (104 EGFR/cell) cells to Cy3-EGF-Au NP. Cytotoxicity was evaluated in clonogenic assays. Results The proportion of total administered radioactivity that was internalized by MDA-MB-468 and MCF-7 cells was 15% and 1.3%, respectively (mixing ratio of EGF:Au of 160). This differential uptake in the two cell lines was confirmed using confocal microscopy. 111In-EGF-Au NP were significantly more radiotoxic to MDA-MB-468 than MCF-7 cells with a surviving fraction of 17.1 ± 4.4% versus 89.8 ± 1.4% (p < 0.001) after exposure for 4 h. Conclusions An 111In-labeled EGF-Au nanosystem was developed. It enabled targeted delivery of a high 111In payload specifically to EGFR-positive cancer cells leading to radiotoxicity that can be exploited for molecularly targeted radiotherapy. PMID:26999580

  6. Technical Note: Partial body irradiation of mice using a customized PMMA apparatus and a clinical 3D planning/LINAC radiotherapy system

    SciTech Connect

    Karagounis, Ilias V.; Koukourakis, Michael I. E-mail: mkoukour@med.duth.gr; Abatzoglou, Ioannis M.

    2016-05-15

    Purpose: In vivo radiobiology experiments involving partial body irradiation (PBI) of mice are of major importance because they allow for the evaluation of individual organ tolerance; overcoming current limitations of experiments using lower dose, whole body irradiation. In the current study, the authors characterize and validate an effective and efficient apparatus for multiple animal PBI, directed to the head, thorax, or abdomen of mice. Methods: The apparatus is made of polymethylmethacrylate and consists of a rectangular parallelepiped prism (40 cm × 16 cm × 8 cm), in which five holes were drilled to accomodate standard 60 ml syringes, each housing an unanesthetized, fully immobilized mouse. Following CT-scanning and radiotherapy treatment planning, radiation fields were designed to irradiate the head, thorax, or abdomen of the animal. Thermoluminescent dosimeters (TLDs) were used to confirm the treatment planning dosimetry for primary beam and scattered radiation. Results: Mice are efficiently placed into 60 ml syringes and immobilized, without the use of anesthetics. Although partial rotational movement around the longitudinal axis and a minor 2 mm forward/backward movement are permitted, this does not compromise the irradiation of the chosen body area. TLDs confirmed the dose values predicted by the treatment planning dosimetry, both for primary beam and scattered radiation. Conclusions: The customized PMMA apparatus described and validated is cost-effective, convenient to use, and efficient in performing PBI without the use of anesthesia. The developed apparatus permits the isolated irradiation of the mouse head, thorax, and abdomen. Importantly, the apparatus allows the delivery of PBI to five mice, simultaneously, representing an efficient way to effectively expose a large number of animals to PBI through multiple daily fractions, simulating clinical radiotherapy treatment schedules.

  7. EGF-coated gold nanoparticles provide an efficient nano-scale delivery system for the molecular radiotherapy of EGFR-positive cancer.

    PubMed

    Song, Lei; Falzone, Nadia; Vallis, Katherine A

    2016-11-01

    Purpose Radiolabeled antibodies and peptides hold promise for molecular radiotherapy but are often limited by a low payload resulting in inadequate delivery of radioactivity to tumour tissue and, therefore, modest therapeutic effect. We developed a facile synthetic method of radiolabeling indium-111 ((111)In) to epidermal growth factor (EGF)-gold nanoparticles ((111)In-EGF-Au NP) with a high payload. Materials and methods EGF-Au NP were prepared via an interaction between gold and the disulphide bonds of EGF and radiolabeled using (111)InCl3. Targeting efficiency was investigated by quantitating internalized radioactivity and by confocal imaging following exposure of MDA-MB-468 (1.3 × 10(6) EGFR/cell) and MCF-7 (10(4) EGFR/cell) cells to Cy3-EGF-Au NP. Cytotoxicity was evaluated in clonogenic assays. Results The proportion of total administered radioactivity that was internalized by MDA-MB-468 and MCF-7 cells was 15% and 1.3%, respectively (mixing ratio of EGF:Au of 160). This differential uptake in the two cell lines was confirmed using confocal microscopy. (111)In-EGF-Au NP were significantly more radiotoxic to MDA-MB-468 than MCF-7 cells with a surviving fraction of 17.1 ± 4.4% versus 89.8 ± 1.4% (p < 0.001) after exposure for 4 h. Conclusions An (111)In-labeled EGF-Au nanosystem was developed. It enabled targeted delivery of a high (111)In payload specifically to EGFR-positive cancer cells leading to radiotoxicity that can be exploited for molecularly targeted radiotherapy.

  8. 3D Radiotherapy Can Be Safely Combined With Sandwich Systemic Gemcitabine Chemotherapy in the Management of Pancreatic Cancer: Factors Influencing Outcome

    SciTech Connect

    Spry, Nigel Harvey, Jennifer; MacLeod, Craig; Borg, Martin; Ngan, Samuel Y.; Millar, Jeremy L.; Graham, Peter; Zissiadis, Yvonne; Kneebone, Andrew; Carroll, Susan; Davies, Terri; Reece, William H.H.; Iacopetta, Barry; Goldstein, David

    2008-04-01

    Purpose: The aim of this Phase II study was to examine whether concurrent continuous infusion 5-fluorouracil (CI 5FU) plus three-dimensional conformal planning radiotherapy sandwiched between gemcitabine chemotherapy is effective, tolerable, and safe in the management of pancreatic cancer. Methods and Materials: Patients were enrolled in two strata: (1) resected pancreatic cancer at high risk of local relapse (postsurgery arm, n = 22) or (2) inoperable pancreatic cancer in head or body without metastases (locally advanced arm, n = 41). Gemcitabine was given at 1,000 mg/m{sup 2} weekly for 3 weeks followed by 1 week rest then 5-6 weeks of radiotherapy and concurrent CI 5FU (200 mg/m{sup 2}/day). After 4 weeks' rest, gemcitabine treatment was reinitiated for 12 weeks. Results: For the two arms combined, treatment-related Grade 3 and 4 toxicities were reported by 25 (39.7%) and 7 (11.1%) patients, respectively. No significant late renal or hepatic toxicity was observed. In the postsurgery arm (R1 54.5%), median time to progressive disease from surgery was 11.0 months, median time to failure of local control was 32.9 months, and median survival time was 15.6 months. The 1- and 2-year survival rates were 63.6% and 31.8%. No significant associations between outcome and mutations in K-ras or TP53 or microsatellite instability were identified. Post hoc investigation of cancer antigen 19-9 levels found baseline levels and increases postbaseline were associated with shorter survival (p = 0.0061 and p < 0.0001, respectively). Conclusions: This three-dimensional chemoradiotherapy regimen is safe and promising, with encouraging local control for a substantial proportion of patients, and merits testing in a randomized trial.

  9. Development and Validation of a Small Animal Immobilizer and Positioning System for the Study of Delivery of Intracranial and Extracranial Radiotherapy Using the Gamma Knife System.

    PubMed

    Awan, Musaddiq J; Dorth, Jennifer; Mani, Arvind; Kim, Haksoo; Zheng, Yiran; Mislmani, Mazen; Welford, Scott; Yuan, Jiankui; Wessels, Barry W; Lo, Simon S; Letterio, John; Machtay, Mitchell; Sloan, Andrew; Sohn, Jason W

    2017-04-01

    The purpose of this research is to establish a process of irradiating mice using the Gamma Knife as a versatile system for small animal irradiation and to validate accurate intracranial and extracranial dose delivery using this system. A stereotactic immobilization device was developed for small animals for the Gamma Knife head frame allowing for isocentric dose delivery. Intercranial positional reproducibility of a reference point from a primary reference animal was verified on an additional mouse. Extracranial positional reproducibility of the mouse aorta was verified using 3 mice. Accurate dose delivery was validated using film and thermoluminescent dosimeter measurements with a solid water phantom. Gamma Knife plans were developed to irradiate intracranial and extracranial targets. Mice were irradiated validating successful targeted radiation dose delivery. Intramouse positional variability of the right mandible reference point across 10 micro-computed tomography scans was 0.65 ± 0.48 mm. Intermouse positional reproducibility across 2 mice at the same reference point was 0.76 ± 0.46 mm. The accuracy of dose delivery was 0.67 ± 0.29 mm and 1.01 ± 0.43 mm in the coronal and sagittal planes, respectively. The planned dose delivered to a mouse phantom was 2 Gy at the 50% isodose with a measured thermoluminescent dosimeter dose of 2.9 ± 0.3 Gy. The phosphorylated form of member X of histone family H2A (γH2AX) staining of irradiated mouse brain and mouse aorta demonstrated adjacent tissue sparing. In conclusion, our system for preclinical studies of small animal irradiation using the Gamma Knife is able to accurately deliver intracranial and extracranial targeted focal radiation allowing for preclinical experiments studying focal radiation.

  10. [Location of radiotherapy centers: an exploratory geographic analysis for Belgium].

    PubMed

    Cotteels, C; Peeters, D; Coucke, P A; Thomas, I

    2012-10-01

    The distance between the patient's home and a radiotherapy department may represent a hurdle for the patient and influence treatment choice. Therefore, it is necessary to check whether the geographical distribution of radiotherapy centers is in accordance with cancer incidence, taking also into account the cost of travelling to the radiotherapy department. The objective of this study is double; first, to map the current locations of radiotherapy centers across the country and second, to evaluate the observed spatial disparities with appropriate tools. A model of operational research (P-median) is used to suggest the optimal locations and allocations and to compare them with the current situation. This is an exploratory study with simple inputs. It helps to better understand the current geographical distribution of radiotherapy centers in Belgium as well as its possible limitations. RESULTS-CONCLUSION: It appears that the current situation is on the average acceptable in terms of accessibility to the service and that the method presents huge potentialities for decision making so as to yield a spatial system that is both efficient and equitable. Copyright © 2012 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  11. Improved outcome of nasopharyngeal carcinoma treated with conventional radiotherapy

    SciTech Connect

    Palazzi, Mauro . E-mail: mauro.palazzi@istitutotumori.mi.it; Guzzo, Marco; Tomatis, Stefano Ph.D.; Cerrotta, Annamaria; Potepan, Paolo; Quattrone, Pasquale; Cantu, Giulio

    2004-12-01

    Purpose: To describe the outcome of patients with nonmetastatic nasopharyngeal carcinoma (NPC) treated with conventional radiotherapy at a single institution. Methods and materials: From 1990 to 1999, 171 consecutive patients with NPC were treated with conventional (two-dimensional) radiotherapy. Tumor histology was undifferentiated in 82% of cases. Tumor-node-metastasis Stage (American Joint Committee on Cancer/International Union Against Cancer 1997 system) was I in 6%, II in 36%, III in 22%, and IV in 36% of patients. Mean total radiation dose was 68.4 Gy. Chemotherapy was given to 62% of the patients. The median follow-up for surviving patients was 6.3 years (range, 3.1-13.1 years). Results: The 5-year overall survival, disease-specific survival, and disease-free survival rates were 72%, 74%, and 62%, respectively. The 5-year local, regional, and distant control rates were 84%, 80%, and 83% respectively. Late effects of radiotherapy were prospectively recorded in 100 patients surviving without relapse; 44% of these patients had Grade 3 xerostomia, 33% had Grade 3 dental damage, and 11% had Grade 3 hearing loss. Conclusions: This analysis shows an improved outcome for patients treated from 1990 to 1999 compared with earlier retrospective series, despite the use of two-dimensional radiotherapy. Late toxicity, however, was substantial with conventional radiotherapy.

  12. Low-dose prophylactic craniospinal radiotherapy for intracranial germinoma

    SciTech Connect

    Schoenfeld, Gordon O.; Amdur, Robert J. . E-mail: amdurrj@ufl.edu; Schmalfuss, Ilona M.; Morris, Christopher G.; Keole, Sameer R.; Mendenhall, William M.; Marcus, Robert B.

    2006-06-01

    Purpose: To report outcomes of patients with localized intracranial germinoma treated with low-dose craniospinal irradiation (CSI) followed by a boost to the ventricular system and primary site. Methods and Materials: Thirty-one patients had pathologically confirmed intracranial germinoma and no spine metastases. Low-dose CSI was administered in 29 patients: usually 21 Gy of CSI, 9.0 Gy of ventricular boost, and a 19.5-Gy tumor boost, all at 1.5 Gy per fraction. Our neuroradiologist recorded three-dimensional tumor size on magnetic resonance images before, during, and after radiotherapy. Results: With a median follow-up of 7.0 years, 29 of 31 patients (94%) are disease free. One failure had nongerminomatous histology; the initial diagnosis was a sampling error. Of 3 patients who did not receive CSI, 1 died. No patient developed myelopathy, visual deficits, dementia, or skeletal growth problems. In locally controlled patients, tumor response according to magnetic resonance scan was nearly complete within 6 months after radiotherapy. Conclusions: Radiotherapy alone with low-dose prophylactic CSI cures almost all patients with localized intracranial germinoma. Complications are rare when the daily dose of radiotherapy is limited to 1.5 Gy and the total CSI dose to 21 Gy. Patients without a near-complete response to radiotherapy should undergo resection to rule out a nongerminomatous element.

  13. Breast Molecular Profiling and Radiotherapy Considerations.

    PubMed

    Mahmoud, Omar; Haffty, Bruce G

    2016-01-01

    The last decade has seen major changes in the management of breast cancer. Heterogeneity regarding histology, therapeutic response, dissemination patterns, and patient outcome is evident. Molecular profiling provides an accurate tool to predict treatment outcome compared with classical clinicopathologic features. The genomic profiling unveiled the heterogeneity of breast cancer and identified distinct biologic subtypes. These advanced techniques were integrated into the clinical management; predicting systemic therapy benefit and overall survival. Utilizing genotyping to guide locoregional management decisions needs further characterization. In this chapter we will review available data on molecular classification of breast cancer, their association with locoregional outcome, their radiobiological properties and radiotherapy considerations.

  14. Particle radiotherapy with carbon ion beams

    PubMed Central

    2013-01-01

    Carbon ion radiotherapy offers superior dose conformity in the treatment of deep-seated malignant tumours compared with conventional X-ray therapy. In addition, carbon ion beams have a higher relative biological effectiveness compared with protons or X-ray beams. The algorithm of treatment planning and beam delivery system is tailored to the individual parameters of the patient. The present article reviews the available literatures for various disease sites including the head and neck, skull base, lung, liver, prostate, bone and soft tissues and pelvic recurrence of rectal cancer as well as physical and biological properties. PMID:23497542

  15. Expanding global access to radiotherapy.

    PubMed

    Atun, Rifat; Jaffray, David A; Barton, Michael B; Bray, Freddie; Baumann, Michael; Vikram, Bhadrasain; Hanna, Timothy P; Knaul, Felicia M; Lievens, Yolande; Lui, Tracey Y M; Milosevic, Michael; O'Sullivan, Brian; Rodin, Danielle L; Rosenblatt, Eduardo; Van Dyk, Jacob; Yap, Mei Ling; Zubizarreta, Eduardo; Gospodarowicz, Mary

    2015-09-01

    Radiotherapy is a critical and inseparable component of comprehensive cancer treatment and care. For many of the most common cancers in low-income and middle-income countries, radiotherapy is essential for effective treatment. In high-income countries, radiotherapy is used in more than half of all cases of cancer to cure localised disease, palliate symptoms, and control disease in incurable cancers. Yet, in planning and building treatment capacity for cancer, radiotherapy is frequently the last resource to be considered. Consequently, worldwide access to radiotherapy is unacceptably low. We present a new body of evidence that quantifies the worldwide coverage of radiotherapy services by country. We show the shortfall in access to radiotherapy by country and globally for 2015-35 based on current and projected need, and show substantial health and economic benefits to investing in radiotherapy. The cost of scaling up radiotherapy in the nominal model in 2015-35 is US$26·6 billion in low-income countries, $62·6 billion in lower-middle-income countries, and $94·8 billion in upper-middle-income countries, which amounts to $184·0 billion across all low-income and middle-income countries. In the efficiency model the costs were lower: $14·1 billion in low-income, $33·3 billion in lower-middle-income, and $49·4 billion in upper-middle-income countries-a total of $96·8 billion. Scale-up of radiotherapy capacity in 2015-35 from current levels could lead to saving of 26·9 million life-years in low-income and middle-income countries over the lifetime of the patients who received treatment. The economic benefits of investment in radiotherapy are very substantial. Using the nominal cost model could produce a net benefit of $278·1 billion in 2015-35 ($265·2 million in low-income countries, $38·5 billion in lower-middle-income countries, and $239·3 billion in upper-middle-income countries). Investment in the efficiency model would produce in the same period an even

  16. Introduction to suspension levels: radiotherapy.

    PubMed

    Horton, P; Lillicrap, S; Lamm, I-L; Lehmann, W

    2013-02-01

    In 2007, the European Commission (EC) commissioned a group of experts to undertake the revision of Report Radiation Protection (RP 91) 'Criteria for acceptability of radiological (including radiotherapy) and nuclear medicine installations' written in 1997. The revised draft report was submitted to the EC in 2010, who issued it for public consultation. The EC has commissioned the same group of experts to consider the comments of the public consultation for further improvement of the revised report. The EC intends to publish the final report under its Radiation Report Series as RP 162. This paper describes the background to the selection of the key performance parameters for radiotherapy equipment and sets out the sources of their criteria of acceptability including suspension levels for a wide range of radiotherapy equipment.

  17. Inflammatory Skin Conditions Associated With Radiotherapy.

    PubMed

    Hernández Aragüés, I; Pulido Pérez, A; Suárez Fernández, R

    2017-04-01

    Radiotherapy for cancer is used increasingly. Because skin cells undergo rapid turnover, the ionizing radiation of radiotherapy has collateral effects that are often expressed in inflammatory reactions. Some of these reactions-radiodermatitis and recall phenomenon, for example-are very familiar to dermatologists. Other, less common radiotherapy-associated skin conditions are often underdiagnosed but must also be recognized.

  18. Stereotactic linear accelerator radiotherapy for pituitary tumors.

    PubMed

    Ajithkumar, Thankama; Brada, Michael

    2004-01-01

    Last decade has seen important advances in radiotherapy technology which combine precise tumor localization with accurate targeted delivery of radiation. This technique of high precision conformal radiotherapy, described as stereotactic radiotherapy or radiosurgery, uses modern linear accelerators available in most radiation oncology departments. The article describes the new technique as applied to the treatment of pituitary adenoma and reviews published clinical results.

  19. Radiotherapy supports protective tumor-specific immunity

    PubMed Central

    Gupta, Anurag; Sharma, Anu; von Boehmer, Lotta; Surace, Laura; Knuth, Alexander; van den Broek, Maries

    2012-01-01

    Radiotherapy is an important therapeutic option for the treatment of cancer. Growing evidence indicates that, besides inducing an irreversible DNA damage, radiotherapy promotes tumor-specific immune response, which significantly contribute to therapeutic efficacy. We postulate that radiotherapy activates tumor-associated dendritic cells, thus changing the tolerogenic tumor environment into an immunogenic one. PMID:23264910

  20. Could Radiotherapy Effectiveness Be Enhanced by Electromagnetic Field Treatment?

    PubMed Central

    Francisco, Artacho-Cordón; del Mar, Salinas-Asensio María; Irene, Calvente; Sandra, Ríos-Arrabal; Josefa, León; Elisa, Román-Marinetto; Nicolás, Olea; Isabel, Núñez María

    2013-01-01

    One of the main goals in radiobiology research is to enhance radiotherapy effectiveness without provoking any increase in toxicity. In this context, it has been proposed that electromagnetic fields (EMFs), known to be modulators of proliferation rate, enhancers of apoptosis and inductors of genotoxicity, might control tumor recruitment and, thus, provide therapeutic benefits. Scientific evidence shows that the effects of ionizing radiation on cellular compartments and functions are strengthened by EMF. Although little is known about the potential role of EMFs in radiotherapy (RT), the radiosensitizing effect of EMFs described in the literature could support their use to improve radiation effectiveness. Thus, we hypothesized that EMF exposure might enhance the ionizing radiation effect on tumor cells, improving the effects of RT. The aim of this paper is to review reports of the effects of EMFs in biological systems and their potential therapeutic benefits in radiotherapy. PMID:23867611

  1. The use of antioxidants in radiotherapy-induced skin toxicity.

    PubMed

    Amber, Kyle T; Shiman, Michael I; Badiavas, Evangelos V

    2014-01-01

    Radiation-induced skin damage is one of the most common complications of radiotherapy. In order to combat these side effects, patients often turn to alternative therapies, which often include antioxidants. Antioxidants such as those in the polyphenol chemical class, xanthine derivatives, tocepherol, sucralfate, and ascorbate have been studied for their use in either preventing or treating radiotherapy-induced skin damage. Apart from their known role as free radical scavengers, some of these antioxidants appear to alter cytokine release affecting cutaneous and systemic changes. We review the role of antioxidants in treating and preventing radiation-induced skin damage as well as the possible complications of using such therapy.

  2. A new fixation aid for the radiotherapy of eye tumors.

    PubMed

    Buchgeister, Markus; Grisanti, Salvatore; Süsskind, Daniela; Bamberg, Michael; Paulsen, Frank

    2007-12-01

    A modified swim goggle holding a light spot as an optical guide for actively aligning the eye in a reproducible orientation has been constructed to perform radiotherapy of ocular tumors. This device is compatible with computed tomography (CT) and magnetic resonance imaging systems. Image fusion of these data sets yielded clinically acceptable results. The reproducibility of the eye's positioning is tested by repeated CT. The eye's alignment during radiotherapy is monitored by an infrared TV camera with individual markings of the eye's position on the TV-monitor screen. From 2003-2006, 50 patients were treated with this fixation aid by radiosurgery with good patient compliance.

  3. Radia2: A new tool for radiotherapy verification

    NASA Astrophysics Data System (ADS)

    Ovejero, M. C.; Vega-Leal, A. Pérez; Cortés-Giraldo, M. A.; Abou-Haidar, Z.; Bocci, A.; Gallardo, M. I.; Espino, J. M.; Álvarez, M. A. G.; Quesada, J. M.; Arráns, R.

    2013-06-01

    Radiotherapy is nowadays a proven technique in cancer treatments. Within the evolution of radiotherapy treatments towards more complex techniques, the need of new dosimetric methods for treatment verifications has appeared. In order to reach an improved dosimetric method, a collaboration was started to transfer knowledge from nuclear reaction instrumentation to medical applications, involving several departments from the University of Seville, Centro Nacional de Aceleradores (CNA), the Hospital Universitario Virgen Macarena and the company Inabensa. The first prototype, patent pending [2], gave very promising results. Currently, a critical review is being carried out to create an improved system.

  4. A new fixation aid for the radiotherapy of eye tumors

    SciTech Connect

    Buchgeister, Markus; Grisanti, Salvatore; Suesskind, Daniela; Bamberg, Michael; Paulsen, Frank

    2007-12-15

    A modified swim goggle holding a light spot as an optical guide for actively aligning the eye in a reproducible orientation has been constructed to perform radiotherapy of ocular tumors. This device is compatible with computed tomography (CT) and magnetic resonance imaging systems. Image fusion of these data sets yielded clinically acceptable results. The reproducibility of the eye's positioning is tested by repeated CT. The eye's alignment during radiotherapy is monitored by an infrared TV camera with individual markings of the eye's position on the TV-monitor screen. From 2003-2006, 50 patients were treated with this fixation aid by radiosurgery with good patient compliance.

  5. Second Malignant Neoplasms Following Radiotherapy

    PubMed Central

    Kumar, Sanath

    2012-01-01

    More than half of all cancer patients receive radiotherapy as a part of their treatment. With the increasing number of long-term cancer survivors, there is a growing concern about the risk of radiation induced second malignant neoplasm [SMN]. This risk appears to be highest for survivors of childhood cancers. The exact mechanism and dose-response relationship for radiation induced malignancy is not well understood, however, there have been growing efforts to develop strategies for the prevention and mitigation of radiation induced cancers. This review article focuses on the incidence, etiology, and risk factors for SMN in various organs after radiotherapy. PMID:23249860

  6. Metrological Issues in Molecular Radiotherapy

    NASA Astrophysics Data System (ADS)

    D'Arienzo, Marco; Capogni, Marco; Smyth, Vere; Cox, Maurice; Johansson, Lena; Solc, Jaroslav; Bobin, Christophe; Rabus, Hans; Joulaeizadeh, Leila

    2014-08-01

    The therapeutic effect from molecular radiation therapy (MRT), on both tumour and normal tissue, is determined by the radiation absorbed dose. Recent research indicates that as a consequence of biological variation across patients the absorbed dose can vary, for the same administered activity, by as much as two orders of magnitude. The international collaborative EURAMET-EMRP project "Metrology for molecular radiotherapy (MetroMRT)" is addressing this problem. The overall aim of the project is to develop methods of calibrating and verifying clinical dosimetry in MRT. In the present paper an overview of the metrological issues in molecular radiotherapy is provided.

  7. External beam radiotherapy for unresectable hepatocellular carcinoma.

    PubMed

    Abdel-Rahman, Omar; Elsayed, Zeinab

    2017-03-07

    Hepatocellular carcinoma is the most common liver neoplasm, the sixth most common cancer worldwide, and the third most common cause of cancer mortality. Moreover, its incidence has increased dramatically in the past decade. While surgical resection and liver transplantation are the main curative treatments, only around 20% of people with early hepatocellular carcinoma may benefit from these therapies. Current treatment options for unresectable hepatocellular carcinoma include various ablative and transarterial therapies in addition to the drug sorafenib. To assess the benefits and harms of external beam radiotherapy in the management of localised unresectable hepatocellular carcinoma. We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE (OvidSP), Embase (OvidSP), Science Citation Index Expanded (Web of Science), and clinicaltrials.gov registry. We also checked reference lists of primary original studies and review articles manually for further related articles (cross-references) up to October 6, 2016. Eligible studies included all randomised clinical trials comparing external beam radiotherapy either as a monotherapy or in combination with other systemic or locoregional therapies versus placebo, no treatment, or other systemic or locoregional therapies for people with unresectable hepatocellular carcinoma. We used standard methodological procedures expected by Cochrane. We used a random-effects model as well as a fixed-effect model meta-analysis but in case of discrepancy between the two models (e.g. one giving a significant intervention effect, the other no significant intervention effect), we reported both results; otherwise, we reported only the results from the fixed-effect model meta-analysis. We assessed risk of bias of the included trials using predefined risk of bias domains; assessed risks of random errors with Trial Sequential Analysis; and

  8. Patterns of care of radiotherapy in México

    PubMed Central

    Poitevin-Chacón, Adela; Hinojosa-Gómez, José

    2012-01-01

    Aim This survey is performed to learn about the structure of radiotherapy in México. Background Radiation oncology practice is increasing because of the higher incidence of cancer. There is no published data about radiotherapy in México. Materials and methods A questionnaire was sent to the 83 registered centers in the database of the Mexican regulatory agency. One out of the 32 states has no radiotherapy. 27 centers from 14 states provided their answers. Results 829 patients are treated annually with any radiotherapy modality in each center. Two centers have one cobalt machine, 7 have a cobalt and a linac and 10 have more than one linac. Five centers use 2D planning systems, 22 use 3D; 9, conventional simulators; 22, CT based simulation, and 1 center has no simulation. Most of the centers verify beams with films, electronic portal image devices and cone beam CTs are also used. Intensity modulated and image guided radiotherapy are performed in 5 states. Breast, prostate, cervix, lung, rectum and head and neck cancer are the six most common locations. There are 45 public and 38 private centers, 2 dedicated to children. Two gamma knife units, 5 Novalis systems, 1 tomotherapy and 2 cyberknife machines are working. All centers have at least one radiation oncologist, one physicist and one radiotherapist. Conclusions Definitive conclusions cannot be drawn from this limited feedback due to a low participation of centers. This survey about radiotherapy in Mexico shows the heterogeneity of equipment as well as medical and technical staff in the whole country. PMID:24416531

  9. [Which rules apply to hypofractionated radiotherapy?].

    PubMed

    Supiot, S; Clément-Colmou, K; Paris, F; Corre, I; Chiavassa, S; Delpon, G

    2015-10-01

    Hypofractionated radiotherapy is now more widely prescribed due to improved targeting techniques (intensity modulated radiotherapy, image-guided radiotherapy and stereotactic radiotherapy). Low dose hypofractionated radiotherapy is routinely administered mostly for palliative purposes. High or very high dose hypofractionated irradiation must be delivered according to very strict procedures since every minor deviation can lead to major changes in dose delivery to the tumor volume and organs at risk. Thus, each stage of the processing must be carefully monitored starting from the limitations and the choice of the hypofractionation technique, tumour contouring and dose constraints prescription, planning and finally dose calculation and patient positioning verification.

  10. Excellent Local Control With Stereotactic Radiotherapy Boost After External Beam Radiotherapy in Patients With Nasopharyngeal Carcinoma

    SciTech Connect

    Hara, Wendy; Loo, Billy W.; Goffinet, Don R.; Chang, Steven D.; Adler, John R.; Pinto, Harlan A.; Fee, Willard E.; Kaplan, Michael J.; Fischbein, Nancy J.; Le, Quynh-Thu

    2008-06-01

    Purpose: To determine long-term outcomes in patients receiving stereotactic radiotherapy (SRT) as a boost after external beam radiotherapy (EBRT) for locally advanced nasopharyngeal carcinoma (NPC). Methods and Materials: Eight-two patients received an SRT boost after EBRT between September 1992 and July 2006. Nine patients had T1, 30 had T2, 12 had T3, and 31 had T4 tumors. Sixteen patients had Stage II, 19 had Stage III, and 47 had Stage IV disease. Patients received 66 Gy of EBRT followed by a single-fraction SRT boost of 7-15 Gy, delivered 2-6 weeks after EBRT. Seventy patients also received cisplatin-based chemotherapy delivered concurrently with and adjuvant to radiotherapy. Results: At a median follow-up of 40.7 months (range, 6.5-144.2 months) for living patients, there was only 1 local failure in a patient with a T4 tumor. At 5 years, the freedom from local relapse rate was 98%, freedom from nodal relapse 83%, freedom from distant metastasis 68%, freedom from any relapse 67%, and overall survival 69%. Late toxicity included radiation-related retinopathy in 3, carotid aneurysm in 1, and radiographic temporal lobe necrosis in 10 patients, of whom 2 patients were symptomatic with seizures. Of 10 patients with temporal lobe necrosis, 9 had T4 tumors. Conclusion: Stereotactic radiotherapy boost after EBRT provides excellent local control for patients with NPC. Improved target delineation and dose homogeneity of radiation delivery for both EBRT and SRT is important to avoid long-term complications. Better systemic therapies for distant control are needed.

  11. Radiotherapy for Esthesioneuroblastoma: Is Elective Nodal Irradiation Warranted in the Multimodality Treatment Approach?

    SciTech Connect

    Noh, O Kyu; Lee, Sang-wook; Yoon, Sang Min; Kim, Sung Bae; Kim, Sang Yoon; Kim, Chang Jin; Jo, Kyung Ja; Choi, Eun Kyung; Song, Si Yeol; Kim, Jong Hoon; Ahn, Seung Do

    2011-02-01

    Purpose: The role of elective nodal irradiation (ENI) in radiotherapy for esthesioneuroblastoma (ENB) has not been clearly defined. We analyzed treatment outcomes of patients with ENB and the frequency of cervical nodal failure in the absence of ENI. Methods and Materials: Between August 1996 and December 2007, we consulted with 19 patients with ENB regarding radiotherapy. Initial treatment consisted of surgery alone in 2 patients; surgery and postoperative radiotherapy in 4; surgery and adjuvant chemotherapy in 1; surgery, postoperative radiotherapy, and chemotherapy in 3; and chemotherapy followed by radiotherapy or concurrent chemoradiotherapy in 5. Five patients did not receive planned radiotherapy because of disease progression. Including 2 patients who received salvage radiotherapy, 14 patients were treated with radiotherapy. Elective nodal irradiation was performed in 4 patients with high-risk factors, including 3 with cervical lymph node metastasis at presentation. Results: Fourteen patients were analyzable, with a median follow-up of 27 months (range, 7-64 months). The overall 3-year survival rate was 73.4%. Local failure occurred in 3 patients (21.4%), regional cervical failure in 3 (21.4%), and distant failure in 2 (14.3%). No cervical nodal failure occurred in patients treated with combined systemic chemotherapy regardless of ENI. Three cervical failures occurred in the 4 patients treated with ENI or neck dissection (75%), none of whom received systemic chemotherapy. Conclusions: ENI during radiotherapy for ENB seems to play a limited role in preventing cervical nodal failure. Omitting ENI may be an option if patients are treated with a combination of radiotherapy and chemotherapy.

  12. Clinical Applications of 3-D Conformal Radiotherapy

    NASA Astrophysics Data System (ADS)

    Miralbell, Raymond

    Although a significant improvement in cancer cure (i.e. 20% increment) has been obtained in the last 2-3 decades, 30-40% of patients still fail locally after curative radiotherapy. In order to improve local tumor control rates with radiotherapy high doses to the tumor volume are frequently necessary. Three-dimensional conformal radiation therapy (3-D CRT) is used to denote a spectrum of radiation planning and delivery techniques that rely on three-dimensional imaging to define the target (tumor) and to distinguish it from normal tissues. Modern, high-precision radiotherapy (RT) techniques are needed in order to implement the goal of optimal tumor destruction delivering minimal dose to the non-target normal tissues. A better target definition is nowadays possible with contemporary imaging (computerized tomography, magnetic resonance imaging, and positron emission tomography) and image registration technology. A highly precise dose distributions can be obtained with optimal 3-D CRT treatment delivery techniques such as stereotactic RT, intensity modulated RT (IMRT), or protontherapy (the latter allowing for in-depth conformation). Patient daily set-up repositioning and internal organ immobilization systems are necessary before considering to undertake any of the above mentioned high-precision treatment approaches. Prostate cancer, brain tumors, and base of skull malignancies are among the sites most benefitting of dose escalation approaches. Nevertheless, a significant dose reduction to the normal tissues in the vicinity of the irradiated tumor also achievable with optimal 3-D CRT may also be a major issue in the treatment of pediatric tumors in order to preserve growth, normal development, and to reduce the risk of developing radiation induced diseases such as cancer or endocrinologic disorders.

  13. Big Data Analytics for Prostate Radiotherapy

    PubMed Central

    Coates, James; Souhami, Luis; El Naqa, Issam

    2016-01-01

    Radiation therapy is a first-line treatment option for localized prostate cancer and radiation-induced normal tissue damage are often the main limiting factor for modern radiotherapy regimens. Conversely, under-dosing of target volumes in an attempt to spare adjacent healthy tissues limits the likelihood of achieving local, long-term control. Thus, the ability to generate personalized data-driven risk profiles for radiotherapy outcomes would provide valuable prognostic information to help guide both clinicians and patients alike. Big data applied to radiation oncology promises to deliver better understanding of outcomes by harvesting and integrating heterogeneous data types, including patient-specific clinical parameters, treatment-related dose–volume metrics, and biological risk factors. When taken together, such variables make up the basis for a multi-dimensional space (the “RadoncSpace”) in which the presented modeling techniques search in order to identify significant predictors. Herein, we review outcome modeling and big data-mining techniques for both tumor control and radiotherapy-induced normal tissue effects. We apply many of the presented modeling approaches onto a cohort of hypofractionated prostate cancer patients taking into account different data types and a large heterogeneous mix of physical and biological parameters. Cross-validation techniques are also reviewed for the refinement of the proposed framework architecture and checking individual model performance. We conclude by considering advanced modeling techniques that borrow concepts from big data analytics, such as machine learning and artificial intelligence, before discussing the potential future impact of systems radiobiology approaches. PMID:27379211

  14. External radiotherapy in thyroid cancers

    SciTech Connect

    Tubiana, M.; Haddad, E.; Schlumberger, M.; Hill, C.; Rougier, P.; Sarrazin, D.

    1985-05-01

    Surgery is the most effective treatment for thyroid cancer; however, in some subsets of patients, the role of radiotherapy (RT) is important. The main indication for external-beam RT is incomplete surgery. When neoplastic tissue is left behind at surgery, RT must be considered, but only if an experienced surgeon feels that everything that can be done has been done. Generally, in those patients, the neoplastic tissue involves the larynx, trachea, esophagus, blood vessels or mediastinum. Of 539 patients with differentiated thyroid cancer treated at Villejuif, France, until 1976, 97 were treated by external radiotherapy after an incomplete surgical excision. Fifteen years after irradiation, the survival rate is 57% and is approximately 40% at 25 years. The relapse-free survival is lower (39% at 15 years). In patients irradiated with an adequate dose (greater than or equal to 50 Gy) to residual neoplastic tissue after incomplete surgery, the incidence of local recurrence is low (actuarial probability of local recurrence 11% at 15 years versus 23% for patients treated by surgery alone, although the irradiated patients had larger and more extensive tumors). This demonstrates the efficacy of external-beam radiotherapy. The effects of radiotherapy on a residual tumor can be monitored by a serum thyroglobulin assay. With regard to local control of tumors, the effectiveness of radioiodine administration is clearly lower. However, since radioiodine facilitates early detection of distant metastases, a combination of external RT and radioiodine is indicated and is well-tolerated.

  15. Radiotherapy T1 glottic carcinoma

    SciTech Connect

    Zablow, A.I.; Erba, P.S.; Sanfillippo, L.J.

    1989-11-01

    From 1970 to 1985, curative radiotherapy was administered to 63 patients with stage I carcinoma of the true vocal cords. Precision radiotherapeutic technique yields cure rates comparable to surgical results. Good voice quality was preserved in a high percentage of patients.

  16. LINAC based radiosurgery and radiotherapy for neurosurgical diseases: what have we learnt so far.

    PubMed

    Zamzuri, I; Badrisyah, I; Rahman, G I; Pal, H K; Muzaimi, M; Jafri, A M; War, M; Shafie, A M; Ruzman, N I Nik; Biswal, B M; Ahmad, Z

    2011-10-01

    Stereotactic radiosurgery uses a single fraction high dose radiation while stereotactic radiotherapy uses multifractionated lower dose focused radiation. Radiosurgery used rigid CRW head frame while stereotactic radiotherapy utilized GTC or HNL relocatable frames. Stereotactic planning and radiation involved Radionics X-plan and LINAC system. Since December 2001, we have treated 83 lesions from 77 patients using either radiosurgery or fractionated stereotactic radiotherapy. Eighty six percent (86%) of our treated lesions showed favourable outcomes with median follow-up of 32 months (0-7 years). Our lessons from LINAC precision radiation therapy uphold its value as a promising and effective tool in treating a range of nervous system pathologies.

  17. Oral cancer: Current role of radiotherapy and chemotherapy.

    PubMed

    Huang, Shao-Hui; O'Sullivan, Brian

    2013-03-01

    The term oral cavity cancer (OSCC) constitutes cancers of the mucosal surfaces of the lips, floor of mouth, oral tongue, buccal mucosa, lower and upper gingiva, hard palate and retromolar trigone. Treatment approaches for OSCC include single management with surgery, radiotherapy [external beam radiotherapy (EBRT) and/or brachytherapy], as well as adjuvant systemic therapy (chemotherapy and/or target agents); various combinations of these modalities may also be used depending on the disease presentation and pathological findings. The selection of sole or combined modality is based on various considerations that include disease control probability, the anticipated functional and cosmetic outcomes, tumor resectability, patient general condition, and availability of resources and expertise. For resectable OSCC, the mainstay of treatment is surgery, though same practitioners may advocate for the use of radiotherapy alone in selected "early" disease presentations or combined with chemotherapy in more locally advanced stage disease. In general, the latter is more commonly reserved for cases where surgery may be problematic. Thus, primary radiotherapy ± chemotherapy is usually reserved for patients unable to tolerate or who are otherwise unsuited for surgery. On the other hand, brachytherapy may be considered as a sole modality for early small primary tumor. It also has a role as an adjuvant to surgery in the setting of inadequate pathologically assessed resection margins, as does postoperative external beam radiotherapy ± chemotherapy, which is usually reserved for those with unfavorable pathological features. Brachytherapy can also be especially useful in the re-irradiation setting for persistent or recurrent disease or for a second primary arising within a previous radiation field. Biological agents targeting the epithelial growth factor receptor (EGFR) have emerged as a potential modality in combination with radiotherapy or chemoradiotherapy and are currently under

  18. Adjuvant radiotherapy for locally advanced upper tract urothelial carcinoma

    PubMed Central

    Huang, Yun-Ching; Chang, Ying-Hsu; Chiu, Kuo-Hsiung; Shindel, Alan W.; Lai, Chia-Hsuan

    2016-01-01

    There is relatively little literature on adjuvant radiotherapy after radical nephroureterectomy with bladder cuff excision (RNU) for patients with upper tract urothelial carcinoma (UTUC). This study was designed to determine the efficacy of adjuvant radiotherapy for patients with pT3N0M0 UTUC. We retrospectively reviewed 198 patients treated with RNU between December 2001 and January 2015. Postoperative radiotherapy was administered in 40 (20.2%) of patients. Patients who received radiotherapy were younger than those that did not (65.2 vs. 70.5 years, p = 0.023). With median follow up of 29.1 months, Kaplan-Meier analysis with the log-rank test demonstrated no significant differences between those omitting vs receiving adjuvant radiotherapy in regards to 2-year rates of overall survival (72.0% vs. 73.4%, p = 0.979), cancer-specific survival (73.2% vs. 75.3%, p = 0.844), and recurrence-free survival (61.2% vs. 66.3%, p = 0.742). However, in multivariable analysis with Cox regression, young age, absence of chronic kidney disease, negative lymphovascular invasion, negative surgical margin, and adjuvant chemotherapy were also associated with better cancer-specific survival. In conclusion, adjuvant radiotherapy did not offer any significant benefit in terms of overall, cancer-specific, and recurrence-free survivals in patients with pT3N0M0 UTUC after RNU. More effective systemic adjuvant chemotherapy is necessary to improve the outcome of these patients. PMID:27910890

  19. In vivo dosimetry in external beam radiotherapy.

    PubMed

    Mijnheer, Ben; Beddar, Sam; Izewska, Joanna; Reft, Chester

    2013-07-01

    In vivo dosimetry (IVD) is in use in external beam radiotherapy (EBRT) to detect major errors, to assess clinically relevant differences between planned and delivered dose, to record dose received by individual patients, and to fulfill legal requirements. After discussing briefly the main characteristics of the most commonly applied IVD systems, the clinical experience of IVD during EBRT will be summarized. Advancement of the traditional aspects of in vivo dosimetry as well as the development of currently available and newly emerging noninterventional technologies are required for large-scale implementation of IVD in EBRT. These new technologies include the development of electronic portal imaging devices for 2D and 3D patient dosimetry during advanced treatment techniques, such as IMRT and VMAT, and the use of IVD in proton and ion radiotherapy by measuring the decay of radiation-induced radionuclides. In the final analysis, we will show in this Vision 20∕20 paper that in addition to regulatory compliance and reimbursement issues, the rationale for in vivo measurements is to provide an accurate and independent verification of the overall treatment procedure. It will enable the identification of potential errors in dose calculation, data transfer, dose delivery, patient setup, and changes in patient anatomy. It is the authors' opinion that all treatments with curative intent should be verified through in vivo dose measurements in combination with pretreatment checks.

  20. Dose masking feature for BNCT radiotherapy planning

    DOEpatents

    Cook, Jeremy L.; Wessol, Daniel E.; Wheeler, Floyd J.

    2000-01-01

    A system for displaying an accurate model of isodoses to be used in radiotherapy so that appropriate planning can be performed prior to actual treatment on a patient. The nature of the simulation of the radiotherapy planning for BNCT and Fast Neutron Therapy, etc., requires that the doses be computed in the entire volume. The "entire volume" includes the patient and beam geometries as well as the air spaces in between. Isodoses derived from the computed doses will therefore extend into the air regions between the patient and beam geometries and thus depict the unrealistic possibility that radiation deposition occurs in regions containing no physical media. This problem is solved by computing the doses for the entire geometry and then masking the physical and air regions along with the isodose contours superimposed over the patient image at the corresponding plane. The user is thus able to mask out (remove) the contour lines from the unwanted areas of the image by selecting the appropriate contour masking region from the raster image.

  1. In vivo dosimetry in external beam radiotherapy

    SciTech Connect

    Mijnheer, Ben; Beddar, Sam; Izewska, Joanna; Reft, Chester

    2013-07-15

    In vivo dosimetry (IVD) is in use in external beam radiotherapy (EBRT) to detect major errors, to assess clinically relevant differences between planned and delivered dose, to record dose received by individual patients, and to fulfill legal requirements. After discussing briefly the main characteristics of the most commonly applied IVD systems, the clinical experience of IVD during EBRT will be summarized. Advancement of the traditional aspects of in vivo dosimetry as well as the development of currently available and newly emerging noninterventional technologies are required for large-scale implementation of IVD in EBRT. These new technologies include the development of electronic portal imaging devices for 2D and 3D patient dosimetry during advanced treatment techniques, such as IMRT and VMAT, and the use of IVD in proton and ion radiotherapy by measuring the decay of radiation-induced radionuclides. In the final analysis, we will show in this Vision 20/20 paper that in addition to regulatory compliance and reimbursement issues, the rationale for in vivo measurements is to provide an accurate and independent verification of the overall treatment procedure. It will enable the identification of potential errors in dose calculation, data transfer, dose delivery, patient setup, and changes in patient anatomy. It is the authors' opinion that all treatments with curative intent should be verified through in vivo dose measurements in combination with pretreatment checks.

  2. Monte Carlo dose calculations in advanced radiotherapy

    NASA Astrophysics Data System (ADS)

    Bush, Karl Kenneth

    The remarkable accuracy of Monte Carlo (MC) dose calculation algorithms has led to the widely accepted view that these methods should and will play a central role in the radiotherapy treatment verification and planning of the future. The advantages of using MC clinically are particularly evident for radiation fields passing through inhomogeneities, such as lung and air cavities, and for small fields, including those used in today's advanced intensity modulated radiotherapy techniques. Many investigators have reported significant dosimetric differences between MC and conventional dose calculations in such complex situations, and have demonstrated experimentally the unmatched ability of MC calculations in modeling charged particle disequilibrium. The advantages of using MC dose calculations do come at a cost. The nature of MC dose calculations require a highly detailed, in-depth representation of the physical system (accelerator head geometry/composition, anatomical patient geometry/composition and particle interaction physics) to allow accurate modeling of external beam radiation therapy treatments. To perform such simulations is computationally demanding and has only recently become feasible within mainstream radiotherapy practices. In addition, the output of the accelerator head simulation can be highly sensitive to inaccuracies within a model that may not be known with sufficient detail. The goal of this dissertation is to both improve and advance the implementation of MC dose calculations in modern external beam radiotherapy. To begin, a novel method is proposed to fine-tune the output of an accelerator model to better represent the measured output. In this method an intensity distribution of the electron beam incident on the model is inferred by employing a simulated annealing algorithm. The method allows an investigation of arbitrary electron beam intensity distributions and is not restricted to the commonly assumed Gaussian intensity. In a second component of

  3. Enhancing radiotherapy for lung cancer using immunoadjuvants delivered in situ from new design radiotherapy biomaterials: a preclinical study

    NASA Astrophysics Data System (ADS)

    Hao, Yao; Yasmin-Karim, Sayeda; Moreau, Michele; Sinha, Neeharika; Sajo, Erno; Ngwa, Wilfred

    2016-12-01

    Stereotactic Body Radiotherapy schedules. Overall, the preliminary results support ongoing work in developing multifunctional radiotherapy biomaterials for in situ delivery of immunoadjuvants such as anti-CD40 to leverage the abscopal effect, while minimizing systemic toxicities. The potential of extending such an approach to other cancer types is discussed.

  4. Leaf sequencing and dosimetric verification in intensity-modulated radiotherapy

    NASA Astrophysics Data System (ADS)

    Agazaryan, Nzhde

    Although sophisticated means to calculate and deliver intensity modulated radiotherapy (IMRT) have been developed by many groups, methods to verify the delivery, as well as definitions of acceptability of a treatment in terms of these measurements are the most problematic at this stage of advancement of IMRT. Present intensity modulated radiotherapy systems fail to account for many dosimetric characteristics of the delivery system. In this dissertation, a dosimetrically based leaf sequencing algorithm is developed and implemented for multileaf collimated intensity modulated radiotherapy. The dosimetric considerations are investigated and are shown to significantly improve the outcome in terms of an agreement between desired and delivered radiation dose distributions. Subsequently, a system for determining the desirability of a produced intensity modulated radiotherapy plan in terms of deliverability of calculated profiles with the use of a multileaf collimator is developed. Three deliverability scoring indices are defined to evaluate the deliverability of the profiles. Gradient Index (GI) is a measure of the complexity of the profile in terms of gradients. Baseline Index (BI) is the fraction of the profile that is planned to get lower than the minimum level of transmission radiation. Cumulative Monitor Unit Index (CMUI) is the ratio of the cumulative monitor units (CMU) required for obtaining the desired profile to an average dose level in the profile. The dosimetric investigations of the deliverability scoring indices are presented, showing a clear correlation between scoring indices and dosimetric accuracy. Finally, materials and methods are developed for verification of intensity modulated radiotherapy. Dosimetric verification starts from investigations of the developed leaf sequencing algorithm, then extends to dosimetric verification in terms of deliverability, and lastly, dosimetric verification of complete clinical IMRT plans is performed.

  5. Radiotherapy capacity in European countries: an analysis of the Directory of Radiotherapy Centres (DIRAC) database.

    PubMed

    Rosenblatt, Eduardo; Izewska, Joanna; Anacak, Yavuz; Pynda, Yaroslav; Scalliet, Pierre; Boniol, Mathieu; Autier, Philippe

    2013-02-01

    Radiotherapy is used for cure or palliation in around half of patients with cancer. We analysed data on radiotherapy equipment in 33 European countries registered in the Directory of Radiotherapy Centres (DIRAC) database, managed by the International Atomic Energy Agency. As of July, 2012, Europe had 1286 active radiotherapy centres. The average number of teletherapy machines per radiotherapy centre ranged from 1·2 to 7·0 in different countries. Nordic countries, the UK, the Netherlands, and Slovenia all have large centres with four to ten teletherapy machines. Most western and southern European countries have several small centres with one or two machines, with few larger centres. The fragmentation in radiotherapy services that prevails in many European countries might affect the economic burden of radiotherapy and its quality. Eastern and southeastern European countries need to expand and modernise their radiotherapy equipment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Application of EPR dosimetry in bone for ex vivo measurements of doses in radiotherapy patients.

    PubMed

    Krefft, K; Drogoszewska, B; Kaminska, J; Juniewicz, M; Wołąkiewicz, G; Jakacka, I; Ciesielski, B

    2014-11-01

    In the present study, bone samples from three patients treated in radiotherapy facilities in Poland were used for the determination of doses absorbed during radiotherapy. The samples were obtained during surgical treatments of patients performed due to medical indications. For the purpose of retrospective dosimetry, sensitivity of the radiation-induced EPR signal was individually calibrated in the samples by re-irradiation of the samples with known doses. The doses reconstructed in bones extracted within 6 months after irradiation were consistent with those calculated by treatment planning systems. The dose reconstructed in the bone removed 6 y after radiotherapy was ∼14% lower than the calculated one.

  7. [Quality radiotherapy in rectal cancer].

    PubMed

    Capirci, C; Amichetti, M; De Renzis, C

    2001-01-01

    The quality of radiotherapy significantly impacts on the results of treatment, in patients with rectal carcinoma, especially in terms of acute and late toxicity. Based on this assumption, the Italian Association of Radiation Oncology (AIRO) formulated a document aimed to define the standards of radiation treatment for rectal carcinomas. Two different levels of standard were described: a first level, considered as "minimal requirement", and a second level, considered as "optimal treatment". A retrospective evaluation, based on a questionnaire, revealed that in 1996, in most Italian Centers, patients affected by rectal carcinoma received radiation treatment within the first level of proposed standards. A subsequent analysis concerned the evaluation of the level of treatments applied in 2000. In this paper the radiotherapy standards proposed by the AIRO are described in the different phases of the radiation treatment.

  8. Intraoperative radiotherapy for breast cancer

    PubMed Central

    Williams, Norman R.; Pigott, Katharine H.; Brew-Graves, Chris

    2014-01-01

    Intra-operative radiotherapy (IORT) as a treatment for breast cancer is a relatively new technique that is designed to be a replacement for whole breast external beam radiotherapy (EBRT) in selected women suitable for breast-conserving therapy. This article reviews twelve reasons for the use of the technique, with a particular emphasis on targeted intra-operative radiotherapy (TARGIT) which uses X-rays generated from a portable device within the operating theatre immediately after the breast tumour (and surrounding margin of healthy tissue) has been removed. The delivery of a single fraction of radiotherapy directly to the tumour bed at the time of surgery, with the capability of adding EBRT at a later date if required (risk-adaptive technique) is discussed in light of recent results from a large multinational randomised controlled trial comparing TARGIT with EBRT. The technique avoids irradiation of normal tissues such as skin, heart, lungs, ribs and spine, and has been shown to improve cosmetic outcome when compared with EBRT. Beneficial aspects to both institutional and societal economics are discussed, together with evidence demonstrating excellent patient satisfaction and quality of life. There is a discussion of the published evidence regarding the use of IORT twice in the same breast (for new primary cancers) and in patients who would never be considered for EBRT because of their special circumstances (such as the frail, the elderly, or those with collagen vascular disease). Finally, there is a discussion of the role of the TARGIT Academy in developing and sustaining high standards in the use of the technique. PMID:25083504

  9. [Stereotactic radiotherapy for pelvic tumors].

    PubMed

    Mazeron, R; Fumagalli, I

    2014-01-01

    Extracranial stereotactic radiotherapy is booming. The development and spread of dedicated accelerators coupled with efficient methods of repositioning can now allow treatments of mobile lesions with moderate size, with high doses per fraction. Intuitively, except for the prostate, pelvic tumours, often requiring irradiation of regional lymph node drainage, lend little to this type of treatment. However, in some difficult circumstances, such as boost or re-radiation, stereotactic irradiation condition is promising and clinical experiences have already been reported.

  10. A fuzzy convolution model for radiobiologically optimized radiotherapy margins.

    PubMed

    Mzenda, Bongile; Hosseini-Ashrafi, Mir; Gegov, Alex; Brown, David J

    2010-06-07

    In this study we investigate the use of a new knowledge-based fuzzy logic technique to derive radiotherapy margins based on radiotherapy uncertainties and their radiobiological effects. The main radiotherapy uncertainties considered and used to build the model were delineation, set-up and organ motion-induced errors. The radiobiological effects of these combined errors, in terms of prostate tumour control probability and rectal normal tissue complication probability, were used to formulate the rule base and membership functions for a Sugeno type fuzzy system linking the error effect to the treatment margin. The defuzzified output was optimized by convolving it with a Gaussian convolution kernel to give a uniformly varying transfer function which was used to calculate the required treatment margins. The margin derived using the fuzzy technique showed good agreement compared to current prostate margins based on the commonly used margin formulation proposed by van Herk et al (2000 Int. J. Radiat. Oncol. Biol. Phys. 47 1121-35), and has nonlinear variation above combined errors of 5 mm standard deviation. The derived margin is on average 0.5 mm bigger than currently used margins in the region of small treatment uncertainties where margin reduction would be applicable. The new margin was applied in an intensity modulated radiotherapy prostate treatment planning example where margin reduction and a dose escalation regime were implemented, and by inducing equivalent treatment uncertainties, the resulting target and organs at risk doses were found to compare well to results obtained using currently recommended margins.

  11. A new plan quality index for dose painting radiotherapy.

    PubMed

    Park, Yang-Kyun; Park, Soyeon; Wu, Hong-Gyun; Kim, Siyong

    2014-07-08

    Dose painting radiotherapy is considered a promising radiotherapy technology that enables more targeted dose delivery to tumor rich regions while saving critical normal tissues. Obviously, dose painting planning would be more complicated and hard to be evaluated with current plan quality index systems that were developed under the paradigm of uniform dose prescription. In this study, we introduce a new plan quality index, named "index of achievement (IOA)" that assesses how close the planned dose distribution is to the prescribed one in a dose painting radiotherapy plan. By using voxel-based comparison between planned and prescribed dose distributions in its formulation, the index allows for a single-value evaluation regardless of the number of prescribed dose levels, which cannot be achieved with the conventional indices such as conventional homogeneity index. Benchmark calculations using patient data demonstrated feasibility of the index not only for contour-based dose painting plans, but also for dose painting by numbers plans. Also, it was shown that there is strong correlation between the new index and conventional indices, which indicates a potential of the new index as an alternative to conventional ones in general radiotherapy plan evaluation.

  12. Bayesian network models for error detection in radiotherapy plans

    NASA Astrophysics Data System (ADS)

    Kalet, Alan M.; Gennari, John H.; Ford, Eric C.; Phillips, Mark H.

    2015-04-01

    The purpose of this study is to design and develop a probabilistic network for detecting errors in radiotherapy plans for use at the time of initial plan verification. Our group has initiated a multi-pronged approach to reduce these errors. We report on our development of Bayesian models of radiotherapy plans. Bayesian networks consist of joint probability distributions that define the probability of one event, given some set of other known information. Using the networks, we find the probability of obtaining certain radiotherapy parameters, given a set of initial clinical information. A low probability in a propagated network then corresponds to potential errors to be flagged for investigation. To build our networks we first interviewed medical physicists and other domain experts to identify the relevant radiotherapy concepts and their associated interdependencies and to construct a network topology. Next, to populate the network’s conditional probability tables, we used the Hugin Expert software to learn parameter distributions from a subset of de-identified data derived from a radiation oncology based clinical information database system. These data represent 4990 unique prescription cases over a 5 year period. Under test case scenarios with approximately 1.5% introduced error rates, network performance produced areas under the ROC curve of 0.88, 0.98, and 0.89 for the lung, brain and female breast cancer error detection networks, respectively. Comparison of the brain network to human experts performance (AUC of 0.90 ± 0.01) shows the Bayes network model performs better than domain experts under the same test conditions. Our results demonstrate the feasibility and effectiveness of comprehensive probabilistic models as part of decision support systems for improved detection of errors in initial radiotherapy plan verification procedures.

  13. Bayesian network models for error detection in radiotherapy plans.

    PubMed

    Kalet, Alan M; Gennari, John H; Ford, Eric C; Phillips, Mark H

    2015-04-07

    The purpose of this study is to design and develop a probabilistic network for detecting errors in radiotherapy plans for use at the time of initial plan verification. Our group has initiated a multi-pronged approach to reduce these errors. We report on our development of Bayesian models of radiotherapy plans. Bayesian networks consist of joint probability distributions that define the probability of one event, given some set of other known information. Using the networks, we find the probability of obtaining certain radiotherapy parameters, given a set of initial clinical information. A low probability in a propagated network then corresponds to potential errors to be flagged for investigation. To build our networks we first interviewed medical physicists and other domain experts to identify the relevant radiotherapy concepts and their associated interdependencies and to construct a network topology. Next, to populate the network's conditional probability tables, we used the Hugin Expert software to learn parameter distributions from a subset of de-identified data derived from a radiation oncology based clinical information database system. These data represent 4990 unique prescription cases over a 5 year period. Under test case scenarios with approximately 1.5% introduced error rates, network performance produced areas under the ROC curve of 0.88, 0.98, and 0.89 for the lung, brain and female breast cancer error detection networks, respectively. Comparison of the brain network to human experts performance (AUC of 0.90 ± 0.01) shows the Bayes network model performs better than domain experts under the same test conditions. Our results demonstrate the feasibility and effectiveness of comprehensive probabilistic models as part of decision support systems for improved detection of errors in initial radiotherapy plan verification procedures.

  14. The effect of travel distance on radiotherapy utilization in NSW and ACT.

    PubMed

    Gabriel, Gabriel; Barton, Michael; Delaney, Geoff P

    2015-11-01

    It has been estimated that half of all cancer patients should receive radiotherapy during the course of the disease. Actual Radiotherapy Utilization (RTU) rates are usually lower than the optimal rates. Data were collected from all radiotherapy departments (RTD) in New South Wales (NSW) and the Australian Capital Territory (ACT) for the period 2004-06 and were linked to Central Cancer Registries. Geographic Information System (GIS) software was used to calculate road distance between patient residence and the closest RTD. Patients were excluded from the study if their nearest RTD was outside NSW. The overall RTU rate was 26%. The RTU rates decreased with increasing travel distance from patient residence to the nearest RTD (p<0.0001). Multivariate logistic regression shows that male gender, younger age and shorter travel distance were significantly associated with receiving radiotherapy. Patients were 10% less likely to receive radiotherapy for each additional 100 km distance from the nearest RTD (p<0.001). There was a statistically significant reduction in radiotherapy access with longer road distance between patient residence and radiotherapy department. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Uses of megavoltage digital tomosynthesis in radiotherapy

    NASA Astrophysics Data System (ADS)

    Sarkar, Vikren

    , the software was extended to investigate if the digital tomosynthesis dataset could be used in an adaptive radiotherapy regimen through the use of the Pinnacle treatment planning software to recalculate dose delivered. The feasibility study showed that the megavoltage CBDT visually agreed with corresponding megavoltage computed tomography images. The comparative study showed that the best compromise between imaging quality and imaging dose is obtained when 11 projection images, acquired over an imaging angle of 40°, are used with the filtered back-projection algorithm. DART was successfully used to register reference and daily image sets to within 1 mm in-plane and 2.5 mm out of plane. The DART platform was also effectively used to generate updated files that the Pinnacle treatment planning system used to calculate updated dose in a rigidly shifted patient. These doses were then used to calculate a cumulative dose distribution that could be used by a physician as reference to decide when the treatment plan should be updated. In conclusion, this study showed that a software solution is possible to extend existing electronic portal imaging devices to function as cone-beam digital tomosynthesis devices and achieve daily requirement for image guided intensity modulated radiotherapy treatments. The DART platform also has the potential to be used as a part of adaptive radiotherapy solution.

  16. Adjuvant and Definitive Radiotherapy for Adrenocortical Carcinoma

    SciTech Connect

    Sabolch, Aaron; Feng, Mary; Griffith, Kent; Hammer, Gary; Doherty, Gerard; Ben-Josef, Edgar

    2011-08-01

    Purpose: To evaluate the impact of both adjuvant and definitive radiotherapy on local control of adrenocortical carcinoma. Methods and Materials: Outcomes were analyzed from 58 patients with 64 instances of treatment for adrenocortical carcinoma at the University of Michigan's Multidisciplinary Adrenal Cancer Clinic. Thirty-seven of these instances were for primary disease, whereas the remaining 27 were for recurrent disease. Thirty-eight of the treatment regimens involved surgery alone, 10 surgery plus adjuvant radiotherapy, and 16 definitive radiotherapy for unresectable disease. The effects of patient, tumor, and treatment factors were modeled simultaneously using multiple variable Cox proportional hazards regression for associations with local recurrence, distant recurrence, and overall survival. Results: Local failure occurred in 16 of the 38 instances that involved surgery alone, in 2 of the 10 that consisted of surgery plus adjuvant radiotherapy, and in 1 instance of definitive radiotherapy. Lack of radiotherapy use was associated with 4.7 times the risk of local failure compared with treatment regimens that involved radiotherapy (95% confidence interval, 1.2-19.0; p = 0.030). Conclusions: Radiotherapy seems to significantly lower the risk of local recurrence/progression in patients with adrenocortical carcinoma. Adjuvant radiotherapy should be strongly considered after surgical resection.

  17. Software for quantitative analysis of radiotherapy: overview, requirement analysis and design solutions.

    PubMed

    Zhang, Lanlan; Hub, Martina; Mang, Sarah; Thieke, Christian; Nix, Oliver; Karger, Christian P; Floca, Ralf O

    2013-06-01

    Radiotherapy is a fast-developing discipline which plays a major role in cancer care. Quantitative analysis of radiotherapy data can improve the success of the treatment and support the prediction of outcome. In this paper, we first identify functional, conceptional and general requirements on a software system for quantitative analysis of radiotherapy. Further we present an overview of existing radiotherapy analysis software tools and check them against the stated requirements. As none of them could meet all of the demands presented herein, we analyzed possible conceptional problems and present software design solutions and recommendations to meet the stated requirements (e.g. algorithmic decoupling via dose iterator pattern; analysis database design). As a proof of concept we developed a software library "RTToolbox" following the presented design principles. The RTToolbox is available as open source library and has already been tested in a larger-scale software system for different use cases. These examples demonstrate the benefit of the presented design principles.

  18. Technical aspects of internet-based knowledge presentation in radiotherapy.

    PubMed

    Lütttgau, A; Bendl, R

    2001-01-01

    Three-dimensional radiotherapy planning is a complex and time-consuming optimization process which requires much experience. To simplify and to speed up the process of treatment planning as well as to exchange experience and therapeutic knowledge, the department of Medical Physics at the German Cancer Research Centre (DKFZ) in Heidelberg is developing an Internet-based 3D Radiotherapy planning and Information System (IRIS). IRIS designed internet-based client-server application, implemented using Java, CORBA and PVM. The concept of IRIS combines the functionality of an interactive tutorial with a discussion forum, teleconferencing tool and an atlas of dose distributions. Furthermore an integral knowledge-based system provides automatically generated, preoptimized treatment plans. This paper explains the technical design of the system and gives an overview of experiences gained by the technical realization of a first prototype using currently available internet technology. The prototype is currently running for testing in the intranet of DKFZ.

  19. Isolated limb perfusion and external beam radiotherapy for soft tissue sarcomas of the extremity: long-term effects on normal tissue according to the LENT-SOMA scoring system.

    PubMed

    Hoven-Gondrie, Miriam L; Thijssens, Katja M J; Geertzen, Jan H B; Pras, Elisabeth; van Ginkel, Robert J; Hoekstra, Harald J

    2008-05-01

    With the combined treatment procedure of isolated limb perfusion (ILP), delayed surgical resection and external beam radiotherapy (EBRT) for locally advanced soft tissue sarcomas (STS) of the extremities, limb salvage rates of more than 80% can be achieved. However, long-term damage to the healthy surrounding tissue cannot be prevented. We studied the late effects on the normal tissue using the LENT-SOMA scoring system. A total of 32 patients-median age 47 (range 14-71) years-were treated for a locally advanced STS with ILP, surgical resection and often adjuvant 60-70 Gy EBRT. After a median follow-up of 88 (range 17-159) months, the patients were scored, using the LENT-SOMA scales, for the following late tissue damage: muscle/soft tissue, peripheral nerves, skin/subcutaneous tissue and vessels. According to the individual SOM parameters of the LENT-SOMA scales, 20 patients (63%) scored grade-3 toxicity on one or more separate items, reflecting severe symptoms with a negative impact on daily activities. Of these patients, 3 (9%) even scored grade-4 toxicity on some of the parameters, denoting irreversible functional damage necessitating major therapeutic intervention. In evaluating long-term morbidity after a combined treatment procedure for STS of the extremity, using modified LENT-SOMA scores, two-thirds of patients were found to have experienced serious late toxic effects.

  20. A prospective study: current problems in radiotherapy for nasopharyngeal carcinoma in yogyakarta, indonesia.

    PubMed

    Stoker, Sharon D; Wildeman, Maarten A; Fles, Renske; Indrasari, Sagung R; Herdini, Camelia; Wildeman, Pieter L; van Diessen, Judi N A; Tjokronagoro, Maesadji; Tan, I Bing

    2014-01-01

    Nasopharyngeal carcinoma (NPC) has a high incidence in Indonesia. Previous study in Yogyakarta revealed a complete response of 29% and a median overall survival of less than 2 years. These poor treatment outcome are influenced by the long diagnose-to-treatment interval to radiotherapy (DTI) and the extended overall treatment time of radiotherapy (OTT). This study reveals insight why the OTT and DTI are prolonged. All patients treated with curative intent radiotherapy for NPC between July 2011 until October 2012 were included. During radiotherapy a daily diary was kept, containing information on DTI, missed radiotherapy days, the reason for missing and length of OTT. Sixty-eight patients were included. The median DTI was 106 days (95% CI: 98-170). Fifty-nine patients (87%) finished the treatment. The median OTT for radiotherapy was 57 days (95% CI: 57-65). The main reason for missing days was an inoperative radiotherapy machine (36%). Other reasons were patient's poor condition (21%), public holidays (14%), adjustment of the radiation field (7%), power blackout (3%), inoperative treatment planning system (2%) and patient related reasons (9%). Patient's insurance type was correlated to DTI in disadvantage for poor people. Yogyakarta has a lack of sufficient radiotherapy units which causes a delay of 3-4 months, besides the OTT is extended by 10-12 days. This influences treatment outcome to a great extend. The best solution would be creating sufficient radiotherapy units and better management in health care for poor patients. The growing economy in Indonesia will expectantly in time enable these solutions, but in the meantime solutions are needed. Solutions can consist of radiation outside office hours, better maintenance of the facilities and more effort from patient, doctor and nurse to finish treatment in time. These results are valuable when improving cancer care in low and middle income countries.

  1. A Prospective Study: Current Problems in Radiotherapy for Nasopharyngeal Carcinoma in Yogyakarta, Indonesia

    PubMed Central

    Stoker, Sharon D.; Wildeman, Maarten A.; Fles, Renske; Indrasari, Sagung R.; Herdini, Camelia; Wildeman, Pieter L.; van Diessen, Judi N. A.; Tjokronagoro, Maesadji; Tan, I. Bing

    2014-01-01

    Introduction Nasopharyngeal carcinoma (NPC) has a high incidence in Indonesia. Previous study in Yogyakarta revealed a complete response of 29% and a median overall survival of less than 2 years. These poor treatment outcome are influenced by the long diagnose-to-treatment interval to radiotherapy (DTI) and the extended overall treatment time of radiotherapy (OTT). This study reveals insight why the OTT and DTI are prolonged. Method All patients treated with curative intent radiotherapy for NPC between July 2011 until October 2012 were included. During radiotherapy a daily diary was kept, containing information on DTI, missed radiotherapy days, the reason for missing and length of OTT. Results Sixty-eight patients were included. The median DTI was 106 days (95% CI: 98−170). Fifty-nine patients (87%) finished the treatment. The median OTT for radiotherapy was 57 days (95% CI: 57–65). The main reason for missing days was an inoperative radiotherapy machine (36%). Other reasons were patient’s poor condition (21%), public holidays (14%), adjustment of the radiation field (7%), power blackout (3%), inoperative treatment planning system (2%) and patient related reasons (9%). Patient’s insurance type was correlated to DTI in disadvantage for poor people. Conclusion Yogyakarta has a lack of sufficient radiotherapy units which causes a delay of 3–4 months, besides the OTT is extended by 10–12 days. This influences treatment outcome to a great extend. The best solution would be creating sufficient radiotherapy units and better management in health care for poor patients. The growing economy in Indonesia will expectantly in time enable these solutions, but in the meantime solutions are needed. Solutions can consist of radiation outside office hours, better maintenance of the facilities and more effort from patient, doctor and nurse to finish treatment in time. These results are valuable when improving cancer care in low and middle income countries. PMID:24465811

  2. Nanoscale radiotherapy with hafnium oxide nanoparticles.

    PubMed

    Maggiorella, Laurence; Barouch, Gilles; Devaux, Corinne; Pottier, Agnès; Deutsch, Eric; Bourhis, Jean; Borghi, Elsa; Levy, Laurent

    2012-09-01

    There is considerable interest in approaches that could improve the therapeutic window of radiotherapy. In this study, hafnium oxide nanoparticles were designed that concentrate in tumor cells to achieve intracellular high-energy dose deposit. Conventional methods were used, implemented in different ways, to explore interactions of these high-atomic-number nanoparticles and ionizing radiation with biological systems. Using the Monte Carlo simulation, these nanoparticles, when exposed to high-energy photons, were shown to demonstrate an approximately ninefold radiation dose enhancement compared with water. Importantly, the nanoparticles show satisfactory dispersion and persistence within the tumor and they form clusters in the cytoplasm of cancer cells. Marked antitumor activity is demonstrated in human cancer models. Safety is similar in treated and control animals as demonstrated by a broad program of toxicology evaluation. These findings, supported by good tolerance, provide the basis for developing this new type of nanoparticle as a promising anticancer approach in human patients.

  3. Compact Electronic Gamma Source For Radiotherapy

    SciTech Connect

    Chen, A. X.; Antolak, A. J.; Raber, T. N.; Morse, D. H.; Leung, K.-N.

    2011-06-01

    A compact mono-energetic gamma source is being developed to replace the radiological sources used in radiotherapy and other medical instruments. The electronic gamma source utilizes low-energy nuclear reactions to generate gammas in the 0.5 to 1.0 MeV energy range. Independent control of the ion current and energy is achieved by decoupling the RF-driven ion source and pyroelectric crystal-based acceleration systems The ions are accelerated to voltages above 100 keV and bombard a reaction target to produce gammas. Thermal management of the pyroelectric crystal-based accelerator is achieved by convective dielectric fluid flow around the crystal. This approach provides better temperature uniformity in the crystal and higher dielectric strength for suppressing voltage breakdown and enabling faster thermal cycling rates.

  4. An in vitro evaluation of effect of ionizing radiotherapy on push-out strength of fiber posts under cyclic loading.

    PubMed

    Aggarwal, Vivek

    2009-05-01

    Ionizing radiotherapy has a deleterious effect on all vital cells and thus might affect the collagen fibril network of dentin and formation of hybrid layer of composite resins. The present study evaluated the effect of ionizing x-ray radiotherapy on push-out bond strength of fiber posts. Sixty mandibular premolar roots were divided into 4 groups: group I, control group with no irradiation, restored with a quartz fiber post system with cyclic loading; group II, samples were exposed to 60 Gy radiation dosage and than restored; group III, samples were restored and then irradiated; and group IV, samples were restored during irradiation. A push-out bond strength test was done. Radiotherapy significantly reduced the push-out bond strength of fiber posts. Patients undergoing ionizing radiotherapy might have a less than ideal prognosis of fiber posts luted with dual cure resin cement with total etch bonding system, if restorations are done after radiotherapy.

  5. Radiotherapy and local control in rectal cancer.

    PubMed

    Valentini, V; Rosetto, M E; Fares, C; Mantini, G; Salvi, G; Turriziani, A

    1998-01-01

    Recurrence is a stage in the natural history of rectal cancer. Preoperative radiotherapy or postoperative radiochemotherapy lower the rate of recurrence, improving local control. From 1980 to 1997, at the "Divisione di Radioterapia" of the "Università Cattolica del S. Cuore" of Rome 380 patients with rectal cancer of early clinical stage T2-3, candidates for surgery for cure, underwent radiation therapy. 119 patients underwent postoperative radiotherapy (45-50 Gy); 45 patients underwent "sandwich" radiotherapy (45 Gy:27 Gy before and 28 Gy after surgery), of whom 7 were treated with preoperative radiotherapy alone; 145 patients underwent preoperative concomitant radiochemotherapy according to 3 different protocols, radiotherapy (38 Gy) combined with mitomycin C and 5-FU; radiotherapy (50.4 Gy) combined with cisplatin and 5-FU; radiotherapy (45 Gy) combined with 5-FU and folinic acid. 71 patients were treated with preoperative radiotherapy (38 Gy) combined with IORT (10 Gy). Median follow-up was 6 years. Overall local control was 85% at 3 years, 83% at 5 years, 81% at 10 years. The rate of local control at 5 years was: 76% for postoperative radiotherapy, 83% for "sandwich" radiotherapy, 84% for preoperative radiochemotherapy and 93% for preoperative radiotherapy combined with IORT. Local control was shown to be significantly better with preoperative treatment as compared to postoperative treatment (p = 0.02). The incidence of metastases was 35% in the patients with local recurrence and 16% in those with local control. The difference in survival was highly significant in patients with local control as compared to those with local recurrence: at 5 years 87% and 32% respectively. Patients with local control showed a lower incidence of metastasis and a better survival.

  6. Impact of radiotherapy for pediatric CNS atypical teratoid/rhabdoid tumor (single institute experience)

    SciTech Connect

    Chen, Y.-W.; Wong, T.-T.; Ho, Donald Ming-Tak; Huang, P.-I.; Chang, K.-P.; Shiau, C.-Y.; Yen, S.-H. . E-mail: shyen@vghtpe.gov.tw

    2006-03-15

    Purpose: To assess outcomes and prognostic factors in radiotherapy of pediatric central nervous system atypical teratoid/rhabdoid tumor (AT/RT). Methods and Materials: Seventeen patients with central nervous system AT/RT were retrospectively reviewed after curative radiotherapy as primary or adjuvant therapy between January 1990 and December 2003. Overall and failure-free survival rates were calculated using the Kaplan-Meier method. The log-rank method was used to compare the effects of dosage (>50 Gy or {<=}50 Gy) and treatment duration (>45 days or {<=}45 days). Multivariate analysis was performed for prognostic factors. Results: Median overall survival and failure-free survival were 17 and 11 months, respectively. The 3 longest-surviving patients were older, underwent gross tumor removal, and completed both craniospinal and focal boost irradiation. Multivariate analysis revealed a significant relationship between the following: overall survival and performance status (p = 0.019), failure-free survival and total irradiation dose (p = 0.037), time interval between surgery and radiotherapy initiation (p = 0.031), and time interval between surgery and radiotherapy end point (p = 0.047). Conclusion: Radiotherapy is crucial in the treatment of AT/RT. We recommend initiating radiotherapy immediately postoperatively and before systemic chemotherapy in pediatric patients {>=}3 years of age.

  7. [MRI-based radiotherapy planning].

    PubMed

    Largent, A; Nunes, J-C; Lafond, C; Périchon, N; Castelli, J; Rolland, Y; Acosta, O; de Crevoisier, R

    2017-07-06

    MRI-based radiotherapy planning is a topical subject due to the introduction of a new generation of treatment machines combining a linear accelerator and a MRI. One of the issues for introducing MRI in this task is the lack of information to provide tissue density information required for dose calculation. To cope with this issue, two strategies may be distinguished from the literature. Either a synthetic CT scan is generated from the MRI to plan the dose, or a dose is generated from the MRI based on physical underpinnings. Within the first group, three approaches appear: bulk density mapping assign a homogeneous density to different volumes of interest manually defined on a patient MRI; machine learning-based approaches model local relationship between CT and MRI image intensities from multiple data, then applying the model to a new MRI; atlas-based approaches use a co-registered training data set (CT-MRI) which are registered to a new MRI to create a pseudo CT from spatial correspondences in a final fusion step. Within the second group, physics-based approaches aim at computing the dose directly from the hydrogen contained within the tissues, quantified by MRI. Excepting the physics approach, all these methods generate a synthetic CT called "pseudo CT", on which radiotherapy planning will be finally realized. This literature review shows that atlas- and machine learning-based approaches appear more accurate dosimetrically. Bulk density approaches are not appropriate for bone localization. The fastest methods are machine learning and the slowest are atlas-based approaches. The less automatized are bulk density assignation methods. The physical approaches appear very promising methods. Finally, the validation of these methods is crucial for a clinical practice, in particular in the perspective of adaptive radiotherapy delivered by a linear accelerator combined with an MRI scanner. Copyright © 2017. Published by Elsevier SAS.