Head-and-Neck Target Delineation Among Radiation Oncology Residents After a Teaching Intervention: A Prospective, Blinded Pilot Study

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

Bekelman, Justin E.; Wolden, Suzanne; Lee, Nancy

Purpose: We conducted this study to determine the feasibility of incorporating a teaching intervention on target delineation into the educational curriculum of a radiation oncology residency program and to assess the short-term effects on resident skills. Methods and Materials: The study schema consisted of a baseline evaluation, the teaching intervention, and a follow-up evaluation. At the baseline evaluation, the participants contoured three clinical tumor volumes (CTVs) (70 Gy, 59.4 Gy, and 54 Gy) on six contrast-enhanced axial computed tomography images of a de-identified patient with Stage T2N2bM0 squamous cell carcinoma of the right base of the tongue. The participants attendedmore » a series of head-and-neck oncology and anatomy seminars. The teaching intervention consisted of a didactic lecture and an interactive hands-on practical session designed to improve the knowledge and skills for target delineation in the head and neck. At the follow-up evaluation, the residents again contoured the CTVs. Results: Of the 14 eligible residents, 11 (79%) actually participated in the study. For all participants, but especially for those who had not had previous experience with head-and-neck target delineation, the teaching intervention was associated with improvement in the delineation of the node-negative neck (CTV 54 Gy contour). Regardless of clinical experience, participants had difficulty determining what should be included in the CTV 59.4 Gy contour to ensure adequate coverage of potential microscopic disease. Conclusion: Incorporating a teaching intervention into the education curriculum of a radiation oncology residency program is feasible and was associated with short-term improvements in target delineation skills. Subsequent interventions will require content refinement, additional validation, longer term follow-up, and multi-institutional collaboration.« less

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

Williamson, Casey W.; Green, Garrett; Noticewala, Sonal S.

Purpose: Validated models are needed to justify strategies to define planning target volumes (PTVs) for intact cervical cancer used in clinical practice. Our objective was to independently validate a previously published shape model, using data collected prospectively from clinical trials. Methods and Materials: We analyzed 42 patients with intact cervical cancer treated with daily fractionated pelvic intensity modulated radiation therapy and concurrent chemotherapy in one of 2 prospective clinical trials. We collected online cone beam computed tomography (CBCT) scans before each fraction. Clinical target volume (CTV) structures from the planning computed tomography scan were cast onto each CBCT scan aftermore » rigid registration and manually redrawn to account for organ motion and deformation. We applied the 95% isodose cloud from the planning computed tomography scan to each CBCT scan and computed any CTV outside the 95% isodose cloud. The primary aim was to determine the proportion of CTVs that were encompassed within the 95% isodose volume. A 1-sample t test was used to test the hypothesis that the probability of complete coverage was different from 95%. We used mixed-effects logistic regression to assess effects of time and patient variability. Results: The 95% isodose line completely encompassed 92.3% of all CTVs (95% confidence interval, 88.3%-96.4%), not significantly different from the 95% probability anticipated a priori (P=.19). The overall proportion of missed CTVs was small: the grand mean of covered CTVs was 99.9%, and 95.2% of misses were located in the anterior body of the uterus. Time did not affect coverage probability (P=.71). Conclusions: With the clinical implementation of a previously proposed PTV definition strategy based on a shape model for intact cervical cancer, the probability of CTV coverage was high and the volume of CTV missed was low. This PTV expansion strategy is acceptable for clinical trials and practice; however, we recommend

Consistency in seroma contouring for partial breast radiotherapy: Impact of guidelines

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

Wong, Elaine K.; Truong, Pauline T.; Kader, Hosam A.

2006-10-01

Purpose: Inconsistencies in contouring target structures can undermine the precision of conformal radiation therapy (RT) planning and compromise the validity of clinical trial results. This study evaluated the impact of guidelines on consistency in target volume contouring for partial breast RT planning. Methods and Materials: Guidelines for target volume definition for partial breast radiation therapy (PBRT) planning were developed by members of the steering committee for a pilot trial of PBRT using conformal external beam planning. In phase 1, delineation of the breast seroma in 5 early-stage breast cancer patients was independently performed by a 'trained' cohort of four radiationmore » oncologists who were provided with these guidelines and an 'untrained' cohort of four radiation oncologists who contoured without guidelines. Using automated planning software, the seroma target volume (STV) was expanded into a clinical target volume (CTV) and planning target volume (PTV) for each oncologist. Means and standard deviations were calculated, and two-tailed t tests were used to assess differences between the 'trained' and 'untrained' cohorts. In phase 2, all eight radiation oncologists were provided with the same contouring guidelines, and were asked to delineate the seroma in five new cases. Data were again analyzed to evaluate consistency between the two cohorts. Results: The 'untrained' cohort contoured larger seroma volumes and had larger CTVs and PTVs compared with the 'trained' cohort in three of five cases. When seroma contouring was performed after review of contouring guidelines, the differences in the STVs, CTVs, and PTVs were no longer statistically significant. Conclusion: Guidelines can improve consistency among radiation oncologists performing target volume delineation for PBRT planning.« less

Investigation of interfractional shape variations based on statistical point distribution model for prostate cancer radiation therapy.

PubMed

Shibayama, Yusuke; Arimura, Hidetaka; Hirose, Taka-Aki; Nakamoto, Takahiro; Sasaki, Tomonari; Ohga, Saiji; Matsushita, Norimasa; Umezu, Yoshiyuki; Nakamura, Yasuhiko; Honda, Hiroshi

2017-05-01

The setup errors and organ motion errors pertaining to clinical target volume (CTV) have been considered as two major causes of uncertainties in the determination of the CTV-to-planning target volume (PTV) margins for prostate cancer radiation treatment planning. We based our study on the assumption that interfractional target shape variations are not negligible as another source of uncertainty for the determination of precise CTV-to-PTV margins. Thus, we investigated the interfractional shape variations of CTVs based on a point distribution model (PDM) for prostate cancer radiation therapy. To quantitate the shape variations of CTVs, the PDM was applied for the contours of 4 types of CTV regions (low-risk, intermediate- risk, high-risk CTVs, and prostate plus entire seminal vesicles), which were delineated by considering prostate cancer risk groups on planning computed tomography (CT) and cone beam CT (CBCT) images of 73 fractions of 10 patients. The standard deviations (SDs) of the interfractional random errors for shape variations were obtained from covariance matrices based on the PDMs, which were generated from vertices of triangulated CTV surfaces. The correspondences between CTV surface vertices were determined based on a thin-plate spline robust point matching algorithm. The systematic error for shape variations was defined as the average deviation between surfaces of an average CTV and planning CTVs, and the random error as the average deviation of CTV surface vertices for fractions from an average CTV surface. The means of the SDs of the systematic errors for the four types of CTVs ranged from 1.0 to 2.0 mm along the anterior direction, 1.2 to 2.6 mm along the posterior direction, 1.0 to 2.5 mm along the superior direction, 0.9 to 1.9 mm along the inferior direction, 0.9 to 2.6 mm along the right direction, and 1.0 to 3.0 mm along the left direction. Concerning the random errors, the means of the SDs ranged from 0.9 to 1.2 mm along the anterior direction

SU-F-T-200: Dosimetric Variation of Organs at Risk for Recurrent Nasopharyngeal Carcinoma (rNPC) Patients Treated by Carbon Ion Beams

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

Wang, W; Sheng, Y; Shahnazi, K

2016-06-15

Purpose: Investigate the factors which affect the doses of organs at risk (OARs) for head and neck carbon ion therapy. Methods: Ten locally recurrent nasopharyngeal carcinoma cases with similar prescriptions were selected. All patients’ organs at risk (OARs) as well as CTVs were contoured by an experienced physician. Carbon ion treatment plans were created using a Syngo treatment planning system (Siemens, Germany). The CTVs were expanded to make optimized target volumes (OTVs) by considering treatment uncertainties and OAR protections. All plans were reviewed by this physician to be clinically acceptable. The OTV was expanded an additional 3mm to define themore » volume where beam spots could be put. A volume was also drawn 6 mm around the OTV to approximate the 50 % dose volume. The volumes where the OARs overlapped the OTV + 3 mm and OTV + 6 mm volumes, termed residual volumes, were then calculated. Results: The residual volumes within OTV + 3 mm were directly related to the OAR maximum dose. The percentage of the residual volume within the OTV + 6 mm with respect to the OAR volume was strongly related to the OAR mean doses. OAR mean doses also were affected by the beam setups. For example, if the OARs were in the beam entrance, the superior beams would sharply decrease the mean doses of the OARs hit by the lateral beams while increasing the mean doses of the OARs hit by the superior beam; the mean dose of the OARs which were hit by higher weight beams would be higher than the OARs hit by lower weight beams. Conclusion: Physicians should be cautious when contouring OARs, especially those close to CTVs and sensitive to large doses. Planners should set the OTV and beam parameters properly in order to save the OARs.« less

Volumetric Spectroscopic Imaging of Glioblastoma Multiforme Radiation Treatment Volumes

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

Parra, N. Andres; Maudsley, Andrew A.; Gupta, Rakesh K.

Purpose: Magnetic resonance (MR) imaging and computed tomography (CT) are used almost exclusively in radiation therapy planning of glioblastoma multiforme (GBM), despite their well-recognized limitations. MR spectroscopic imaging (MRSI) can identify biochemical patterns associated with normal brain and tumor, predominantly by observation of choline (Cho) and N-acetylaspartate (NAA) distributions. In this study, volumetric 3-dimensional MRSI was used to map these compounds over a wide region of the brain and to evaluate metabolite-defined treatment targets (metabolic tumor volumes [MTV]). Methods and Materials: Volumetric MRSI with effective voxel size of ∼1.0 mL and standard clinical MR images were obtained from 19 GBM patients.more » Gross tumor volumes and edema were manually outlined, and clinical target volumes (CTVs) receiving 46 and 60 Gy were defined (CTV{sub 46} and CTV{sub 60}, respectively). MTV{sub Cho} and MTV{sub NAA} were constructed based on volumes with high Cho and low NAA relative to values estimated from normal-appearing tissue. Results: The MRSI coverage of the brain was between 70% and 76%. The MTV{sub NAA} were almost entirely contained within the edema, and the correlation between the 2 volumes was significant (r=0.68, P=.001). In contrast, a considerable fraction of MTV{sub Cho} was outside of the edema (median, 33%) and for some patients it was also outside of the CTV{sub 46} and CTV{sub 60}. These untreated volumes were greater than 10% for 7 patients (37%) in the study, and on average more than one-third (34.3%) of the MTV{sub Cho} for these patients were outside of CTV{sub 60}. Conclusions: This study demonstrates the potential usefulness of whole-brain MRSI for radiation therapy planning of GBM and revealed that areas of metabolically active tumor are not covered by standard RT volumes. The described integration of MTV into the RT system will pave the way to future clinical trials investigating outcomes in patients treated based

SU-F-T-224: Importance of Timely Review of Daily Cone-Beam CTs: Dosimetric Evaluation of Rejected CBCTs for Head and Neck Patients

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

Andrews, M; Yu, N; Joshi, N

Purpose: To dosimetrically evaluate the importance of timely reviewing daily CBCTs for patients with head and neck cancer. Methods: After each fraction daily cone-beam CT (CBCT) for head and neck patients are reviewed by physicians prior to next treatment. Physician rejected image registrations of CBCT were identified and analyzed for 17 patients. These CBCT images were rigidly fused with planning CT images and the contours from the planning CT were transferred to CBCTs. Because of limited extension in the superior-inferior dimension contours with partial volumes in CBCTs were discarded. The treatment isocenter was placed by applying the clinically recorded shiftsmore » to the volume isocenter of the CBCT. Dose was recalculated at the shifted isocenter using a homogeneous dose calculation algorithm. Dosimetrically relevant changes defined as greater than 5% deviation from the clinically accepted plans but with homogeneous dose calculation were evaluated for the high dose (HD), intermediate dose (ID), and low dose (LD) CTVs, spinal cord, larynx, oropharynx, parotids, and submandibular glands. Results: Among seventeen rejected CBCTS, HD-CTVs, ID-CTVs, and LD-CTVs were completely included in the CBCTs for 17, 1, and 15 patients, respectively. The prescription doses to the HD-CTV, ID-CTV, and LD-CTV were received by < 95% of the CTV volumes in 5/17, 1/1, and 5/15 patients respectively. For the spinal cord, the maximum doses (D0.03cc) were increased > 5% in 13 of 17 patients. For the oropharynx, larynx, parotid, and submandibular glands, the mean dose of these organs at risk was increased > 5% in 7/17, 8/12, 11/16 and 6/16 patients, respectively. Conclusion: Timely review daily CBCTs for head and neck patients under daily CBCT guidance is important, and uncorrected setup errors can translate to dosimetrically relevant dose increases in organsat- risk and dose decreases in the clinical target volumes.« less

Improving the consistency in cervical esophageal target volume definition by special training.

PubMed

Tai, Patricia; Van Dyk, Jake; Battista, Jerry; Yu, Edward; Stitt, Larry; Tonita, Jon; Agboola, Olusegun; Brierley, James; Dar, Rashid; Leighton, Christopher; Malone, Shawn; Strang, Barbara; Truong, Pauline; Videtic, Gregory; Wong, C Shun; Wong, Rebecca; Youssef, Youssef

2002-07-01

Three-dimensional conformal radiation therapy requires the precise definition of the target volume. Its potential benefits could be offset by the inconsistency in target definition by radiation oncologists. In a previous survey of radiation oncologists, a large degree of variation in target volume definition of cervical esophageal cancer was noted for the boost phase of radiotherapy. The present study evaluated whether special training could improve the consistency in target volume definitions. A pre-training survey was performed to establish baseline values. This was followed by a special one-on-one training session on treatment planning based on the RTOG 94-05 protocol to 12 radiation oncologists. Target volumes were redrawn immediately and at 1-2 months later. Post-training vs. pre-training target volumes were compared. There was less variability in the longitudinal positions of the target volumes post-training compared to pre-training (p < 0.05 in 5 of 6 comparisons). One case had more variability due to the lack of a visible gross tumor on CT scans. Transverse contours of target volumes did not show any significant difference pre- or post-training. For cervical esophageal cancer, this study suggests that special training on protocol guidelines may improve consistency in target volume definition. Explicit protocol directions are required for situations where the gross tumor is not easily visible on CT scans. This may be particularly important for multicenter clinical trials, to reduce the occurrences of protocol violations.

Delineation of the primary tumour Clinical Target Volumes (CTV-P) in laryngeal, hypopharyngeal, oropharyngeal and oral cavity squamous cell carcinoma: AIRO, CACA, DAHANCA, EORTC, GEORCC, GORTEC, HKNPCSG, HNCIG, IAG-KHT, LPRHHT, NCIC CTG, NCRI, NRG Oncology, PHNS, SBRT, SOMERA, SRO, SSHNO, TROG consensus guidelines.

PubMed

Grégoire, Vincent; Evans, Mererid; Le, Quynh-Thu; Bourhis, Jean; Budach, Volker; Chen, Amy; Eisbruch, Abraham; Feng, Mei; Giralt, Jordi; Gupta, Tejpal; Hamoir, Marc; Helito, Juliana K; Hu, Chaosu; Hunter, Keith; Johansen, Jorgen; Kaanders, Johannes; Laskar, Sarbani Ghosh; Lee, Anne; Maingon, Philippe; Mäkitie, Antti; Micciche', Francesco; Nicolai, Piero; O'Sullivan, Brian; Poitevin, Adela; Porceddu, Sandro; Składowski, Krzysztof; Tribius, Silke; Waldron, John; Wee, Joseph; Yao, Min; Yom, Sue S; Zimmermann, Frank; Grau, Cai

2018-01-01

Few studies have reported large inter-observer variations in target volume selection and delineation in patients treated with radiotherapy for head and neck squamous cell carcinoma. Consensus guidelines have been published for the neck nodes (see Grégoire et al., 2003, 2014), but such recommendations are lacking for primary tumour delineation. For the latter, two main schools of thoughts are prevailing, one based on geometric expansion of the Gross Tumour Volume (GTV) as promoted by DAHANCA, and the other one based on anatomical expansion of the GTV using compartmentalization of head and neck anatomy. For each anatomic location within the larynx, hypopharynx, oropharynx and oral cavity, and for each T-stage, the DAHANCA proposal has been comprehensively reviewed and edited to include anatomic knowledge into the geometric Clinical Target Volume (CTV) delineation concept. A first proposal was put forward by the leading authors of this publication (VG and CG) and discussed with opinion leaders in head and neck radiation oncology from Europe, Asia, Australia/New Zealand, North America and South America to reach a worldwide consensus. This consensus proposes two CTVs for the primary tumour, the so called CTV-P1 and CVT-P2, corresponding to a high and lower tumour burden, and which should be associated with a high and a lower dose prescription, respectively. Implementation of these guidelines in the daily practice of radiation oncology should contribute to reduce treatment variations from clinicians to clinicians, facilitate the conduct of multi-institutional clinical trials, and contribute to improved care of patients with head and neck carcinoma. Copyright © 2017 Elsevier B.V. All rights reserved.

WE-DE-201-01: BEST IN PHYSICS (THERAPY): A Fast Multi-Target Inverse Treatment Planning Strategy Optimizing Dosimetric Measures for High-Dose-Rate (HDR) Brachytherapy

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

Guthier, C; University Medical Center Mannheim, Mannheim; Harvard Medical School, Boston, MA

Purpose: Inverse treatment planning (ITP) for interstitial HDR brachytherapy of gynecologic cancers seeks to maximize coverage of the clinical target volumes (tumor and vagina) while respecting dose-volume-histogram related dosimetric measures (DMs) for organs at risk (OARs). Commercially available ITP tools do not support DM-based planning because it is computationally too expensive to solve. In this study we present a novel approach that allows fast ITP for gynecologic cancers based on DMs for the first time. Methods: This novel strategy is an optimization model based on a smooth DM-based objective function. The smooth approximation is achieved by utilizing a logistic functionmore » for the evaluation of DMs. The resulting nonconvex and constrained optimization problem is then optimized with a BFGS algorithm. The model was evaluated using the implant geometry extracted from 20 patient treatment plans under an IRB-approved retrospective study. For each plan, the final DMs were evaluated and compared to the original clinical plans. The CTVs were the contoured tumor volume and the contoured surface of the vagina. Statistical significance was evaluated with a one-sided paired Wilcoxon signed-rank test. Results: As did the clinical plans, all generated plans fulfilled the defined DMs for OARs. The proposed strategy showed a statistically significant improvement (p<0.001) in coverage of the tumor and vagina, with absolute improvements of related DMs of (6.9 +/− 7.9)% and (28.2 +/− 12.0)%, respectively. This was achieved with a statistically significant (p<0.01) decrease of the high-dose-related DM for the tumor. The runtime of the optimization was (2.3 +/− 2.0) seconds. Conclusion: We demonstrated using clinical data that our novel approach allows rapid DM-based optimization with improved coverage of CTVs with fewer hot spots. Being up to three orders of magnitude faster than the current clinical practice, the method dramatically shortens planning time.« less

Investigating different computed tomography techniques for internal target volume definition.

PubMed

Yoganathan, S A; Maria Das, K J; Subramanian, V Siva; Raj, D Gowtham; Agarwal, Arpita; Kumar, Shaleen

2017-01-01

The aim of this work was to evaluate the various computed tomography (CT) techniques such as fast CT, slow CT, breath-hold (BH) CT, full-fan cone beam CT (FF-CBCT), half-fan CBCT (HF-CBCT), and average CT for delineation of internal target volume (ITV). In addition, these ITVs were compared against four-dimensional CT (4DCT) ITVs. Three-dimensional target motion was simulated using dynamic thorax phantom with target insert of diameter 3 cm for ten respiration data. CT images were acquired using a commercially available multislice CT scanner, and the CBCT images were acquired using On-Board-Imager. Average CT was generated by averaging 10 phases of 4DCT. ITVs were delineated for each CT by contouring the volume of the target ball; 4DCT ITVs were generated by merging all 10 phases target volumes. Incase of BH-CT, ITV was derived by boolean of CT phases 0%, 50%, and fast CT target volumes. ITVs determined by all CT and CBCT scans were significantly smaller (P < 0.05) than the 4DCT ITV, whereas there was no significant difference between average CT and 4DCT ITVs (P = 0.17). Fast CT had the maximum deviation (-46.1% ± 20.9%) followed by slow CT (-34.3% ± 11.0%) and FF-CBCT scans (-26.3% ± 8.7%). However, HF-CBCT scans (-12.9% ± 4.4%) and BH-CT scans (-11.1% ± 8.5%) resulted in almost similar deviation. On the contrary, average CT had the least deviation (-4.7% ± 9.8%). When comparing with 4DCT, all the CT techniques underestimated ITV. In the absence of 4DCT, the HF-CBCT target volumes with appropriate margin may be a reasonable approach for defining the ITV.

OPS MCC level B/C formulation requirements: Area targets and space volumes processor

NASA Technical Reports Server (NTRS)

Bishop, M. J., Jr.

1979-01-01

The level B/C mathematical specifications for the area targets and space volumes processor (ATSVP) are described. The processor is designed to compute the acquisition-of-signal (AOS) and loss-of-signal (LOS) times for area targets and space volumes. The characteristics of the area targets and space volumes are given. The mathematical equations necessary to determine whether the spacecraft lies within the area target or space volume are given. These equations provide a detailed model of the target geometry. A semianalytical technique for predicting the AOS and LOS time periods is disucssed. This technique was designed to bound the actual visibility period using a simplified target geometry model and unperturbed orbital motion. Functional overview of the ATSVP is presented and it's detailed logic flow is described.

Methods for Reducing Normal Tissue Complication Probabilities in Oropharyngeal Cancer: Dose Reduction or Planning Target Volume Elimination

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

Samuels, Stuart E.; Eisbruch, Avraham; Vineberg, Karen

Purpose: Strategies to reduce the toxicities of head and neck radiation (ie, dysphagia [difficulty swallowing] and xerostomia [dry mouth]) are currently underway. However, the predicted benefit of dose and planning target volume (PTV) reduction strategies is unknown. The purpose of the present study was to compare the normal tissue complication probabilities (NTCP) for swallowing and salivary structures in standard plans (70 Gy [P70]), dose-reduced plans (60 Gy [P60]), and plans eliminating the PTV margin. Methods and Materials: A total of 38 oropharyngeal cancer (OPC) plans were analyzed. Standard organ-sparing volumetric modulated arc therapy plans (P70) were created and then modified by eliminatingmore » the PTVs and treating the clinical tumor volumes (CTVs) only (C70) or maintaining the PTV but reducing the dose to 60 Gy (P60). NTCP dose models for the pharyngeal constrictors, glottis/supraglottic larynx, parotid glands (PGs), and submandibular glands (SMGs) were analyzed. The minimal clinically important benefit was defined as a mean change in NTCP of >5%. The P70 NTCP thresholds and overlap percentages of the organs at risk with the PTVs (56-59 Gy, vPTV{sub 56}) were evaluated to identify the predictors for NTCP improvement. Results: With the P60 plans, only the ipsilateral PG (iPG) benefited (23.9% vs 16.2%; P<.01). With the C70 plans, only the iPG (23.9% vs 17.5%; P<.01) and contralateral SMG (cSMG) (NTCP 32.1% vs 22.9%; P<.01) benefited. An iPG NTCP threshold of 20% and 30% predicted NTCP benefits for the P60 and C70 plans, respectively (P<.001). A cSMG NTCP threshold of 30% predicted for an NTCP benefit with the C70 plans (P<.001). Furthermore, for the iPG, a vPTV{sub 56} >13% predicted benefit with P60 (P<.001) and C70 (P=.002). For the cSMG, a vPTV{sub 56} >22% predicted benefit with C70 (P<.01). Conclusions: PTV elimination and dose-reduction lowered the NTCP of the iPG, and PTV elimination lowered the NTCP of the cSMG. NTCP thresholds and the

Combined Recipe for Clinical Target Volume and Planning Target Volume Margins

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

Stroom, Joep, E-mail: joep.stroom@fundacaochampalimaud.pt; Gilhuijs, Kenneth; Vieira, Sandra

2014-03-01

Purpose: To develop a combined recipe for clinical target volume (CTV) and planning target volume (PTV) margins. Methods and Materials: A widely accepted PTV margin recipe is M{sub geo} = aΣ{sub geo} + bσ{sub geo}, with Σ{sub geo} and σ{sub geo} standard deviations (SDs) representing systematic and random geometric uncertainties, respectively. On the basis of histopathology data of breast and lung tumors, we suggest describing the distribution of microscopic islets around the gross tumor volume (GTV) by a half-Gaussian with SD Σ{sub micro}, yielding as possible CTV margin recipe: M{sub micro} = ƒ(N{sub i}) × Σ{sub micro}, with N{sub i}more » the average number of microscopic islets per patient. To determine ƒ(N{sub i}), a computer model was developed that simulated radiation therapy of a spherical GTV with isotropic distribution of microscopic disease in a large group of virtual patients. The minimal margin that yielded D{sub min} <95% in maximally 10% of patients was calculated for various Σ{sub micro} and N{sub i}. Because Σ{sub micro} is independent of Σ{sub geo}, we propose they should be added quadratically, yielding for a combined GTV-to-PTV margin recipe: M{sub GTV-PTV} = √([aΣ{sub geo}]{sup 2} + [ƒ(N{sub i})Σ{sub micro}]{sup 2}) + bσ{sub geo}. This was validated by the computer model through numerous simultaneous simulations of microscopic and geometric uncertainties. Results: The margin factor ƒ(N{sub i}) in a relevant range of Σ{sub micro} and N{sub i} can be given by: ƒ(N{sub i}) = 1.4 + 0.8log(N{sub i}). Filling in the other factors found in our simulations (a = 2.1 and b = 0.8) yields for the combined recipe: M{sub GTV-PTV} = √((2.1Σ{sub geo}){sup 2} + ([1.4 + 0.8log(N{sub i})] × Σ{sub micro}){sup 2}) + 0.8σ{sub geo}. The average margin difference between the simultaneous simulations and the above recipe was 0.2 ± 0.8 mm (1 SD). Calculating M{sub geo} and M{sub micro} separately and adding them linearly overestimated PTVs

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

Baumann, Brian C.; Bosch, Walter R.; Bahl, Amit

Purpose: To develop multi-institutional consensus clinical target volumes (CTVs) and organs at risk (OARs) for male and female bladder cancer patients undergoing adjuvant radiation therapy (RT) in clinical trials. Methods and Materials: We convened a multidisciplinary group of bladder cancer specialists from 15 centers and 5 countries. Six radiation oncologists and 7 urologists participated in the development of the initial contours. The group proposed initial language for the CTVs and OARs, and each radiation oncologist contoured them on computed tomography scans of a male and female cystectomy patient with input from ≥1 urologist. On the basis of the initial contouring, themore » group updated its CTV and OAR descriptions. The cystectomy bed, the area of greatest controversy, was contoured by another 6 radiation oncologists, and the cystectomy bed contouring language was again updated. To determine whether the revised language produced consistent contours, CTVs and OARs were redrawn by 6 additional radiation oncologists. We evaluated their contours for level of agreement using the Landis-Koch interpretation of the κ statistic. Results: The group proposed that patients at elevated risk for local-regional failure with negative margins should be treated to the pelvic nodes alone (internal/external iliac, distal common iliac, obturator, and presacral), whereas patients with positive margins should be treated to the pelvic nodes and cystectomy bed. Proposed OARs included the rectum, bowel space, bone marrow, and urinary diversion. Consensus language describing the CTVs and OARs was developed and externally validated. The revised instructions were found to produce consistent contours. Conclusions: Consensus descriptions of CTVs and OARs were successfully developed and can be used in clinical trials of adjuvant radiation therapy for bladder cancer.« less

Highly Conformal Craniospinal Radiotherapy Techniques Can Underdose the Cranial Clinical Target Volume if Leptomeningeal Extension through Skull Base Exit Foramina is not Contoured.

PubMed

Noble, D J; Ajithkumar, T; Lambert, J; Gleeson, I; Williams, M V; Jefferies, S J

2017-07-01

Craniospinal irradiation (CSI) remains a crucial treatment for patients with medulloblastoma. There is uncertainty about how to manage meningeal surfaces and cerebrospinal fluid (CSF) that follows cranial nerves exiting skull base foramina. The purpose of this study was to assess plan quality and dose coverage of posterior cranial fossa foramina with both photon and proton therapy. We analysed the radiotherapy plans of seven patients treated with CSI for medulloblastoma and primitive neuro-ectodermal tumours and three with ependymoma (total n = 10). Four had been treated with a field-based technique and six with TomoTherapy™. The internal acoustic meatus (IAM), jugular foramen (JF) and hypoglossal canal (HC) were contoured and added to the original treatment clinical target volume (Plan_CTV) to create a Test_CTV. This was grown to a test planning target volume (Test_PTV) for comparison with a Plan_PTV. Using Plan_CTV and Plan_PTV, proton plans were generated for all 10 cases. The following dosimetry data were recorded: conformity (dice similarity coefficient) and homogeneity index (D 2  - D 98 /D 50 ) as well as median and maximum dose (D 2% ) to Plan_PTV, V 95% and minimum dose (D 99.9% ) to Plan_CTV and Test_CTV and Plan_PTV and Test_PTV, V 95% and minimum dose (D 98% ) to foramina PTVs. Proton and TomoTherapy™ plans were more conformal (0.87, 0.86) and homogeneous (0.07, 0.04) than field-photon plans (0.79, 0.17). However, field-photon plans covered the IAM, JF and HC PTVs better than proton plans (P = 0.002, 0.004, 0.003, respectively). TomoTherapy™ plans covered the IAM and JF better than proton plans (P = 0.000, 0.002, respectively) but the result for the HC was not significant. Adding foramen CTVs/PTVs made no difference for field plans. The mean D min dropped 3.4% from Plan_PTV to Test_PTV for TomoTherapy™ (not significant) and 14.8% for protons (P = 0.001). Highly conformal CSI techniques may underdose meninges and CSF in the dural

Mapping Patterns of Ipsilateral Supraclavicular Nodal Metastases in Breast Cancer: Rethinking the Clinical Target Volume for High-risk Patients

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

Jing, Hao; Wang, Shu-Lian, E-mail: wsl20040118@yahoo.com; Li, Jing

2015-10-01

Purpose: To map the location of metastatic supraclavicular (SCV) lymph nodes (LNMs) in breast cancer patients with SCV node involvement and determine whether and where the radiation therapy clinical target volume (CTV) of this region could be modified in high-risk subsets. Methods and Materials: Fifty-five patients with metastatic SCV LNMs were eligible for geographic mapping and atlas coverage analysis. All LNMs and their epicenters were registered proportionally by referencing the surrounding landmarks onto simulation computed tomography images of a standard patient. CTVs based on selected SCV atlases, including the one by the Radiation Therapy Oncology Group (RTOG) were contoured. Amore » modified SCV CTV was tried and shown to have better involved-node coverage and thus theoretically improved prophylaxis in this setting. Results: A total of 50 (91%) and 45 (81.8%) patients had LNMs in the medial and lateral SCV subregions, respectively. Also, 36 patients (65.5%) had LNMs located at the junction of the jugular-subclavian veins. All nodes were covered in only 25.5% to 41.8% of patients by different atlases. The RTOG atlas covered all nodes in 25.5% of patients. Stratified by the nodes in all the patients as a whole, 49.2% to 81.3% were covered, and the RTOG atlas covered 62.6%. The lateral and posterior borders were the most overlooked locations. Modification by extending the borders to natural anatomic barriers allowed the new CTV to cover all the nodes in 81.8% of patients and encompass 96.1% of all the nodes. Conclusions: According to the distribution of SCV LNMs, the extent of existing atlases might not be adequate for potential metastatic sites in certain groups of patients. The extension of the lateral and posterior CTV borders in high-risk or recurrent patients might be a reasonable approach for increasing coverage. However, additional data in more homogeneous populations with localized disease are needed before routine application.« less

[Clinical target volume delineation for radiotherapy of the esophagus].

PubMed

Lazarescu, I; Thureau, S; Nkhali, L; Pradier, O; Dubray, B

2013-10-01

The dense lymphatic network of the esophagus facilitates tumour spreading along the cephalo-caudal axis and to locoregional lymph nodes. A better understanding of microscopic invasion by tumour cells, based on histological analysis of surgical specimens and analysis of recurrence sites, has justified a reduction in radiotherapy target volumes. The delineation of the clinical target volume (CTV) depends on tumour characteristics (site, histology) and on its spread as assessed on endoscopic ultrasonography and ((18)F)-fluorodeoxyglucose positron-emission tomography (FDG-PET). We propose that positive and negative predictive values for FDG-PET should be used to adapt the CTV according to the risk of nodal involvement. Copyright © 2013 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Postoperative radiation in esophageal squamous cell carcinoma and target volume delineation

PubMed Central

Zhu, Yingming; Li, Minghuan; Kong, Li; Yu, Jinming

2016-01-01

Esophageal cancer is the sixth leading cause of cancer death worldwide, and patients who are treated with surgery alone, without neoadjuvant therapies, experience frequent relapses. Whether postoperative therapies could reduce the recurrence or improve overall survival is still controversial for these patients. The purpose of our review is to figure out the value of postoperative adjuvant therapy and address the disputes about target volume delineation according to published data. Based on the evidence of increased morbidity and disadvantages on patient survival caused by postoperative chemotherapy or radiotherapy (RT) alone provided by studies in the early 1990s, the use of postoperative adjuvant therapies in cases of esophageal squamous cell carcinoma has diminished substantially and has been replaced gradually by neoadjuvant chemoradiation. With advances in surgery and RT, accumulating evidence has recently rekindled interest in the delivery of postoperative RT or chemoradiotherapy in patients with stage T3/T4 or N1 (lymph node positive) carcinomas after radical surgery. However, due to complications with the standard radiation field, a nonconforming modified field has been adopted in most studies. Therefore, we analyze different field applications and provide suggestions on the optimization of the radiation field based on the major sites of relapse and the surgical non-clearance area. For upper and middle thoracic esophageal carcinomas, the bilateral supraclavicular and superior mediastinal areas remain common sites of recurrence and should be encompassed within the clinical target volume. In contrast, a consensus has yet to be reached regarding lower thoracic esophageal carcinomas; the “standard” clinical target volume is still recommended. Further studies of larger sample sizes should focus on different recurrence patterns, categorized by tumor locations, refined classifications, and differing molecular biology, to provide more information on the

A novel method to quantify and compare anatomical shape: application in cervix cancer radiotherapy

NASA Astrophysics Data System (ADS)

Oh, Seungjong; Jaffray, David; Cho, Young-Bin

2014-06-01

Adaptive radiation therapy (ART) had been proposed to restore dosimetric deficiencies during treatment delivery. In this paper, we developed a technique of Geometric reLocation for analyzing anatomical OBjects' Evolution (GLOBE) for a numerical model of tumor evolution under radiation therapy and characterized geometric changes of the target using GLOBE. A total of 174 clinical target volumes (CTVs) obtained from 32 cervical cancer patients were analyzed. GLOBE consists of three main steps; step (1) deforming a 3D surface object to a sphere by parametric active contour (PAC), step (2) sampling a deformed PAC on 642 nodes of icosahedron geodesic dome for reference frame, and step (3) unfolding 3D data to 2D plane for convenient visualization and analysis. The performance was evaluated with respect to (1) convergence of deformation (iteration number and computation time) and (2) accuracy of deformation (residual deformation). Based on deformation vectors from planning CTV to weekly CTVs, target specific (TS) margins were calculated on each sampled node of GLOBE and the systematic (Σ) and random (σ) variations of the vectors were calculated. Population based anisotropic (PBA) margins were generated using van Herk's margin recipe. GLOBE successfully modeled 152 CTVs from 28 patients. Fast convergence was observed for most cases (137/152) with the iteration number of 65 ± 74 (average ± STD) and the computation time of 13.7 ± 18.6 min. Residual deformation of PAC was 0.9 ± 0.7 mm and more than 97% was less than 3 mm. Margin analysis showed random nature of TS-margin. As a consequence, PBA-margins perform similarly to ISO-margins. For example, PBA-margins for 90% patients' coverage with 95% dose level is close to 13 mm ISO-margins in the aspect of target coverage and OAR sparing. GLOBE demonstrates a systematic analysis of tumor motion and deformation of patients with cervix cancer during radiation therapy and numerical modeling of PBA-margin on 642 locations of CTV

Calculation of Lung Cancer Volume of Target Based on Thorax Computed Tomography Images using Active Contour Segmentation Method for Treatment Planning System

NASA Astrophysics Data System (ADS)

Patra Yosandha, Fiet; Adi, Kusworo; Edi Widodo, Catur

2017-06-01

In this research, calculation process of the lung cancer volume of target based on computed tomography (CT) thorax images was done. Volume of the target calculation was done in purpose to treatment planning system in radiotherapy. The calculation of the target volume consists of gross tumor volume (GTV), clinical target volume (CTV), planning target volume (PTV) and organs at risk (OAR). The calculation of the target volume was done by adding the target area on each slices and then multiply the result with the slice thickness. Calculations of area using of digital image processing techniques with active contour segmentation method. This segmentation for contouring to obtain the target volume. The calculation of volume produced on each of the targets is 577.2 cm3 for GTV, 769.9 cm3 for CTV, 877.8 cm3 for PTV, 618.7 cm3 for OAR 1, 1,162 cm3 for OAR 2 right, and 1,597 cm3 for OAR 2 left. These values indicate that the image processing techniques developed can be implemented to calculate the lung cancer target volume based on CT thorax images. This research expected to help doctors and medical physicists in determining and contouring the target volume quickly and precisely.

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

Góra, Joanna, E-mail: joanna.gora@akhwien.at; EBG MedAustron GmbH, Wiener Neustadt; Stock, Markus

Purpose: To investigate robust margin strategies in intensity modulated proton therapy to account for interfractional organ motion in prostate cancer. Methods and Materials: For 9 patients, one planning computed tomography (CT) scan and daily and weekly cone beam CTs (CBCTs) were acquired and coregistered. The following planning target volume (PTV) approaches were investigated: a clinical target volume (CTV) delineated on the planning CT (CTV{sub ct}) plus 10-mm margin (PTV{sub 10mm}); a reduced PTV (PTV{sub Red}): CTV{sub ct} plus 5 mm in the left-right (LR) and anterior-posterior (AP) directions and 8 mm in the inferior-superior (IS) directions; and a PTV{sub Hull}more » method: the sum of CTV{sub ct} and CTVs from 5 CBCTs from the first week plus 3 mm in the LR and IS directions and 5 mm in the AP direction. For each approach, separate plans were calculated using a spot-scanning technique with 2 lateral fields. Results: Each approach achieved excellent target coverage. Differences were observed in volume receiving 98% of the prescribed dose (V{sub 98%}) where PTV{sub Hull} and PTV{sub Red} results were superior to the PTV{sub 10mm} concept. The PTV{sub Hull} approach was more robust to organ motion. The V{sub 98%} for CTVs was 99.7%, whereas for PTV{sub Red} and PTV{sub 10mm} plans, V{sub 98%} was 98% and 96.1%, respectively. Doses to organs at risk were higher for PTV{sub Hull} and PTV{sub 10mm} plans than for PTV{sub Red}, but only differences between PTV{sub 10mm} and PTV{sub Red} were significant. Conclusions: In terms of organ sparing, the PTV{sub 10mm} method was inferior but not significantly different from the PTV{sub Red} and PTV{sub Hull} approaches. PTV{sub Hull} was most insensitive to target motion.« less

Physiological and biochemical principles underlying volume-targeted therapy--the "Lund concept".

PubMed

Nordström, Carl-Henrik

2005-01-01

The optimal therapy of sustained increase in intracranial pressure (ICP) remains controversial. The volume-targeted therapy ("Lund concept") discussed in this article focuses on the physiological volume regulation of the intracranial compartments. The balance between effective transcapillary hydrostatic and osmotic pressures constitutes the driving force for transcapillary fluid exchange. The low permeability for sodium and chloride combined with the high crystalloid osmotic pressure (approximately 5700 mmHg) on both sides of the blood-brain barrier (BBB) counteracts fluid exchange across the intact BBB. Additionally, variations in systemic blood pressure generally are not transmitted to these capillaries because cerebral intracapillary hydrostatic pressure (and blood flow) is physio-logically tightly autoregulated. Under pathophysiological conditions, the BBB may be partially disrupted. Transcapillary water exchange is then determined by the differences in hydrostatic and colloid osmotic pressure between the intra- and extracapillary compartments. Pressure autoregulation of cerebral blood flow is likely to be impaired in these conditions. A high cerebral perfusion pressure accordingly increases intracapillary hydrostatic pressure and leads to increased intracerebral water content and an increase in ICP. The volume-targeted "Lund concept" has been evaluated in experimental and clinical studies to examine the physiological and biochemical (utilizing intracerebral microdialysis) effects, and the clinical experiences have been favorable.

Analysis of nodal coverage utilizing image guided radiation therapy for primary gynecologic tumor volumes

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

Ahmed, Faisal; Loma Linda University Medical Center, Department of Radiation Oncology, Loma Linda, CA; Sarkar, Vikren

Purpose: To evaluate radiation dose delivered to pelvic lymph nodes, if daily Image Guided Radiation Therapy (IGRT) was implemented with treatment shifts based on the primary site (primary clinical target volume [CTV]). Our secondary goal was to compare dosimetric coverage with patient outcomes. Materials and methods: A total of 10 female patients with gynecologic malignancies were evaluated retrospectively after completion of definitive intensity-modulated radiation therapy (IMRT) to their pelvic lymph nodes and primary tumor site. IGRT consisted of daily kilovoltage computed tomography (CT)-on-rails imaging fused with initial planning scans for position verification. The initial plan was created using Varian's Eclipsemore » treatment planning software. Patients were treated with a median radiation dose of 45 Gy (range: 37.5 to 50 Gy) to the primary volume and 45 Gy (range: 45 to 64.8 Gy) to nodal structures. One IGRT scan per week was randomly selected from each patient's treatment course and re-planned on the Eclipse treatment planning station. CTVs were recreated by fusion on the IGRT image series, and the patient's treatment plan was applied to the new image set to calculate delivered dose. We evaluated the minimum, maximum, and 95% dose coverage for primary and nodal structures. Reconstructed primary tumor volumes were recreated within 4.7% of initial planning volume (0.9% to 8.6%), and reconstructed nodal volumes were recreated to within 2.9% of initial planning volume (0.01% to 5.5%). Results: Dosimetric parameters averaged less than 10% (range: 1% to 9%) of the original planned dose (45 Gy) for primary and nodal volumes on all patients (n = 10). For all patients, ≥99.3% of the primary tumor volume received ≥ 95% the prescribed dose (V95%) and the average minimum dose was 96.1% of the prescribed dose. In evaluating nodal CTV coverage, ≥ 99.8% of the volume received ≥ 95% the prescribed dose and the average minimum dose was 93%. In evaluating

TU-AB-BRB-00: New Methods to Ensure Target Coverage

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

NONE

2015-06-15

The accepted clinical method to accommodate targeting uncertainties inherent in fractionated external beam radiation therapy is to utilize GTV-to-CTV and CTV-to-PTV margins during the planning process to design a PTV-conformal static dose distribution on the planning image set. Ideally, margins are selected to ensure a high (e.g. >95%) target coverage probability (CP) in spite of inherent inter- and intra-fractional positional variations, tissue motions, and initial contouring uncertainties. Robust optimization techniques, also known as probabilistic treatment planning techniques, explicitly incorporate the dosimetric consequences of targeting uncertainties by including CP evaluation into the planning optimization process along with coverage-based planning objectives. Themore » treatment planner no longer needs to use PTV and/or PRV margins; instead robust optimization utilizes probability distributions of the underlying uncertainties in conjunction with CP-evaluation for the underlying CTVs and OARs to design an optimal treated volume. This symposium will describe CP-evaluation methods as well as various robust planning techniques including use of probability-weighted dose distributions, probability-weighted objective functions, and coverage optimized planning. Methods to compute and display the effect of uncertainties on dose distributions will be presented. The use of robust planning to accommodate inter-fractional setup uncertainties, organ deformation, and contouring uncertainties will be examined as will its use to accommodate intra-fractional organ motion. Clinical examples will be used to inter-compare robust and margin-based planning, highlighting advantages of robust-plans in terms of target and normal tissue coverage. Robust-planning limitations as uncertainties approach zero and as the number of treatment fractions becomes small will be presented, as well as the factors limiting clinical implementation of robust planning. Learning Objectives: To

Pre- and postoperative radiotherapy for extremity soft tissue sarcoma: Evaluation of inter-observer target volume contouring variability among French sarcoma group radiation oncologists.

PubMed

Sargos, P; Charleux, T; Haas, R L; Michot, A; Llacer, C; Moureau-Zabotto, L; Vogin, G; Le Péchoux, C; Verry, C; Ducassou, A; Delannes, M; Mervoyer, A; Wiazzane, N; Thariat, J; Sunyach, M P; Benchalal, M; Laredo, J D; Kind, M; Gillon, P; Kantor, G

2018-04-01

The purpose of this study was to evaluate, during a national workshop, the inter-observer variability in target volume delineation for primary extremity soft tissue sarcoma radiation therapy. Six expert sarcoma radiation oncologists (members of French Sarcoma Group) received two extremity soft tissue sarcoma radiation therapy cases 1: one preoperative and one postoperative. They were distributed with instructions for contouring gross tumour volume or reconstructed gross tumour volume, clinical target volume and to propose a planning target volume. The preoperative radiation therapy case was a patient with a grade 1 extraskeletal myxoid chondrosarcoma of the thigh. The postoperative case was a patient with a grade 3 pleomorphic undifferentiated sarcoma of the thigh. Contour agreement analysis was performed using kappa statistics. For the preoperative case, contouring agreement regarding GTV, gross tumour volume GTV, clinical target volume and planning target volume were substantial (kappa between 0.68 and 0.77). In the postoperative case, the agreement was only fair for reconstructed gross tumour volume (kappa: 0.38) but moderate for clinical target volume and planning target volume (kappa: 0.42). During the workshop discussion, consensus was reached on most of the contour divergences especially clinical target volume longitudinal extension. The determination of a limited cutaneous cover was also discussed. Accurate delineation of target volume appears to be a crucial element to ensure multicenter clinical trial quality assessment, reproducibility and homogeneity in delivering RT. radiation therapy RT. Quality assessment process should be proposed in this setting. We have shown in our study that preoperative radiation therapy of extremity soft tissue sarcoma has less inter-observer contouring variability. Copyright © 2018 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Diffusion tensor magnetic resonance imaging driven growth modeling for radiotherapy target definition in glioblastoma.

PubMed

Jensen, Morten B; Guldberg, Trine L; Harbøll, Anja; Lukacova, Slávka; Kallehauge, Jesper F

2017-11-01

The clinical target volume (CTV) in radiotherapy is routinely based on gadolinium contrast enhanced T1 weighted (T1w + Gd) and T2 weighted fluid attenuated inversion recovery (T2w FLAIR) magnetic resonance imaging (MRI) sequences which have been shown to over- or underestimate the microscopic tumor cell spread. Gliomas favor spread along the white matter fiber tracts. Tumor growth models incorporating the MRI diffusion tensors (DTI) allow to account more consistently for the glioma growth. The aim of the study was to investigate the potential of a DTI driven growth model to improve target definition in glioblastoma (GBM). Eleven GBM patients were scanned using T1w, T2w FLAIR, T1w + Gd and DTI. The brain was segmented into white matter, gray matter and cerebrospinal fluid. The Fisher-Kolmogorov growth model was used assuming uniform proliferation and a difference in white and gray matter diffusion of a ratio of 10. The tensor directionality was tested using an anisotropy weighting parameter set to zero (γ0) and twenty (γ20). The volumetric comparison was performed using Hausdorff distance, Dice similarity coefficient (DSC) and surface area. The median of the standard CTV (CTVstandard) was 180 cm 3 . The median surface area of CTVstandard was 211 cm 2 . The median surface area of respective CTV γ0 and CTV γ20 significantly increased to 338 and 376 cm 2 , respectively. The Hausdorff distance was greater than zero and significantly increased for both CTV γ0 and CTV γ20 with respective median of 18.7 and 25.2 mm. The DSC for both CTV γ0 and CTV γ20 were significantly below one with respective median of 0.74 and 0.72, which means that 74 and 72% of CTVstandard were included in CTV γ0 and CTV γ20, respectively. DTI driven growth models result in CTVs with a significantly increased surface area, a significantly increased Hausdorff distance and decreased overlap between the standard and model derived volume.

A novel concept for tumour targeting with radiation: Inverse dose-painting or targeting the "Low Drug Uptake Volume".

PubMed

Yaromina, Ala; Granzier, Marlies; Biemans, Rianne; Lieuwes, Natasja; van Elmpt, Wouter; Shakirin, Georgy; Dubois, Ludwig; Lambin, Philippe

2017-09-01

We tested a novel treatment approach combining (1) targeting radioresistant hypoxic tumour cells with the hypoxia-activated prodrug TH-302 and (2) inverse radiation dose-painting to boost selectively non-hypoxic tumour sub-volumes having no/low drug uptake. 18 F-HX4 hypoxia tracer uptake measured with a clinical PET/CT scanner was used as a surrogate of TH-302 activity in rhabdomyosarcomas growing in immunocompetent rats. Low or high drug uptake volume (LDUV/HDUV) was defined as 40% of the GTV with the lowest or highest 18 F-HX4 uptake, respectively. Two hours post TH-302/saline administration, animals received either single dose radiotherapy (RT) uniformly (15 or 18.5Gy) or a dose-painted non-uniform radiation (15Gy) with 50% higher dose to LDUV or HDUV (18.5Gy). Treatment plans were created using Eclipse treatment planning system and radiation was delivered using VMAT. Tumour response was quantified as time to reach 3 times starting tumour volume. Non-uniform RT boosting tumour sub-volume with low TH-302 uptake (LDUV) was superior to the same dose escalation to HDUV (p<0.0001) and uniform RT with the same mean dose 15Gy (p=0.0077). Noteworthy, dose escalation to LDUV required on average 3.5Gy lower dose to the GTV to achieve similar tumour response as uniform dose escalation. The results support targeted dose escalation to non-hypoxic tumour sub-volume with no/low activity of hypoxia-activated prodrugs. This strategy applies on average a lower radiation dose and is as effective as uniform dose escalation to the entire tumour. It could be applied to other type of drugs provided that their distribution can be imaged. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Target volume motion during anal cancer image guided radiotherapy using cone-beam computed tomography.

PubMed

Brooks, Corrinne J; Bernier, Laurence; Hansen, Vibeke N; Tait, Diana M

2018-05-01

Literature regarding image-guidance and interfractional motion of the anal canal (AC) during anal cancer radiotherapy is sparse. This study investigates interfractional AC motion during anal cancer radiotherapy. Bone matched cone beam CT (CBCT) images were acquired for 20 patients receiving anal cancer radiotherapy allowing population systematic and random error calculations. 12 were selected to investigate interfractional AC motion. Primary anal gross tumour volume and clinical target volume (CTVa) were contoured on each CBCT. CBCT CTVa volumes were compared to planning CTVa. CBCT CTVa volumes were combined into a CBCT-CTVa envelope for each patient. Maximum distortion between each orthogonal border of the planning CTVa and CBCT-CTVa envelope was measured. Frequency, volume and location of CBCT-CTVa envelope beyond the planning target volume (PTVa) was analysed. Population systematic and random errors were 1 and 3 mm respectively. 112 CBCTs were analysed in the interfractional motion study. CTVa varied between each imaging session particularly T location patients of anorectal origin. CTVa border expansions ≥ 1 cm were seen inferiorly, anteriorly, posteriorly and left direction. The CBCT-CTVa envelope fell beyond the PTVa ≥ 50% imaging sessions (n = 5). Of these CBCT CTVa distortions beyond PTVa, 44% and 32% were in the upper and lower thirds of PTVa respectively. The AC is susceptible to volume changes and shape deformations. Care must be taken when calculating or considering reducing the PTV margin to the anus. Advances in knowledge: Within a limited field of research, this study provides further knowledge of how the AC deforms during anal cancer radiotherapy.

Intensity-Modulated Radiotherapy for Craniospinal Irradiation: Target Volume Considerations, Dose Constraints, and Competing Risks

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

Parker, William; Filion, Edith; Roberge, David

2007-09-01

Purpose: To report the results of an analysis of dose received to tissues and organs outside the target volume, in the setting of spinal axis irradiation for the treatment of medulloblastoma, using three treatment techniques. Methods and Materials: Treatment plans (total dose, 23.4 Gy) for a standard two-dimensional (2D) technique, a three-dimensional (3D) technique using a 3D imaging-based target volume, and an intensity-modulated radiotherapy (IMRT) technique, were compared for 3 patients in terms of dose-volume statistics for target coverage, as well as organ at risk (OAR) and overall tissue sparing. Results: Planning target volume coverage and dose homogeneity was superiormore » for the IMRT plans for V{sub 95%} (IMRT, 100%; 3D, 96%; 2D, 98%) and V{sub 107%} (IMRT, 3%; 3D, 38%; 2D, 37%). In terms of OAR sparing, the IMRT plan was better for all organs and whole-body contour when comparing V{sub 10Gy}, V{sub 15Gy}, and V{sub 20Gy}. The 3D plan was superior for V{sub 5Gy} and below. For the heart and liver in particular, the IMRT plans provided considerable sparing in terms of V{sub 10Gy} and above. In terms of the integral dose, the IMRT plans were superior for liver (IMRT, 21.9 J; 3D, 28.6 J; 2D, 38.6 J) and heart (IMRT, 9 J; 3D, 14.1J; 2D, 19.4 J), the 3D plan for the body contour (IMRT, 349 J; 3D, 337 J; 2D, 555 J). Conclusions: Intensity-modulated radiotherapy is a valid treatment option for spinal axis irradiation. We have shown that IMRT results in sparing of organs at risk without a significant increase in integral dose.« less

Water-filled balloon in the postoperative resection cavity improves dose distribution to target volumes in radiotherapy of maxillary sinus carcinoma.

PubMed

Zhang, Qun; Lin, Shi-Rong; He, Fang; Kang, De-Hua; Chen, Guo-Zhang; Luo, Wei

2011-11-01

Postoperative radiotherapy is a major treatment for patients with maxillary sinus carcinoma. However, the irregular resection cavity poses a technical difficulty for this treatment, causing uneven dose distribution to target volumes. In this study, we evaluated the dose distribution to target volumes and normal tissues in postoperative intensity-modulated radiotherapy (IMRT) after placing a water-filled balloon into the resection cavity. Three postoperative patients with advanced maxillary sinus carcinoma were selected in this trial. Water-filled balloons and supporting dental stents were fabricated according to the size of the maxillary resection cavity. Simulation CT scans were performed with or without water-filled balloons, IMRT treatment plans were established, and dose distribution to target volumes and organs at risk were evaluated. Compared to those in the treatment plan without balloons, the dose (D98) delivered to 98% of the gross tumor volume (GTV) increased by 2.1 Gy (P = 0.009), homogeneity index (HI) improved by 2.3% (P = 0.001), and target volume conformity index (TCI) of 68 Gy increased by 18.5% (P = 0.011) in the plan with balloons. Dosimetry endpoints of normal tissues around target regions in both plans were not significantly different (P > 0.05) except for the optic chiasm. In the plan without balloons, 68 Gy high-dose regions did not entirely cover target volumes in the ethmoid sinus, posteromedial wall of the maxillary sinus, or surgical margin of the hard palate. In contrast, 68 Gy high-dose regions entirely covered the GTV in the plan with balloons. These results suggest that placing a water-filled balloon in the resection cavity for postoperative IMRT of maxillary sinus carcinoma can reduce low-dose regions and markedly and simultaneously increase dose homogeneity and conformity of target volumes.

Radiotherapy planning: PET/CT scanner performances in the definition of gross tumour volume and clinical target volume.

PubMed

Brianzoni, Ernesto; Rossi, Gloria; Ancidei, Sergio; Berbellini, Alfonso; Capoccetti, Francesca; Cidda, Carla; D'Avenia, Paola; Fattori, Sara; Montini, Gian Carlo; Valentini, Gianluca; Proietti, Alfredo; Algranati, Carlo

2005-12-01

Positron emission tomography is the most advanced scintigraphic imaging technology and can be employed in the planning of radiation therapy (RT). The aim of this study was to evaluate the possible role of fused images (anatomical CT and functional FDG-PET), acquired with a dedicated PET/CT scanner, in delineating gross tumour volume (GTV) and clinical target volume (CTV) in selected patients and thus in facilitating RT planning. Twenty-eight patients were examined, 24 with lung cancer (17 non-small cell and seven small cell) and four with non-Hodgkin's lymphoma in the head and neck region. All patients underwent a whole-body PET scan after a CT scan. The CT images provided morphological volumetric information, and in a second step, the corresponding PET images were overlaid to define the effective target volume. The images were exported off-line via an internal network to an RT simulator. Three patient were excluded from the study owing to change in the disease stage subsequent to the PET/CT study. Among the remaining 25 patients, PET significantly altered the GTV or CTV in 11 (44%) . In five of these 11 cases there was a reduction in GTV or CTV, while in six there was an increase in GTV or CTV. FDG-PET is a highly sensitive imaging modality that offers better visualisation of local and locoregional tumour extension. This study confirmed that co-registration of CT data and FDG-PET images may lead to significant modifications of RT planning and patient management.

Potential impact of 68Ga-PSMA-11 PET/CT on prostate cancer definitive radiation therapy planning.

PubMed

Calais, Jérémie; Kishan, Amar U; Cao, Minsong; Fendler, Wolfgang P; Eiber, Matthias; Herrmann, Ken; Ceci, Francesco; Reiter, Robert E; Rettig, Matthew B; Hegde, John V; Shaverdian, Narek; King, Christopher R; Steinberg, Michael L; Czernin, Johannes; Nickols, Nicholas G

2018-04-13

Background: Standard-of-care imaging for initial staging of prostate cancer (PCa) underestimates disease burden. Prostate specific membrane antigen (PSMA) positron emission tomography/ computed tomography (PET/CT) detects PCa metastasis with superior accuracy with potential impact definitive radiation therapy (RT) planning for non-metastatic PCa. Objectives: i) To determine how often definitive PCa RT planning based on standard target volumes cover 68 Ga-PSMA-11 PET/CT defined disease, and ii) To assess the potential impact of 68 Ga-PSMA-11 PET/CT on definitive PCa RT planning. Patients and Methods: This is a post-hoc analysis of an intention to treat population of 73 patients with localized PCa without prior local therapy who underwent 68 Ga-PSMA PET/CT for initial staging as part of an Investigational New Drug trial. 11/73 were intermediate-risk (15%), 33/73 were high-risk (45%), 22/73 were very high risk (30%), and 7/73 were N1 (9.5%). Clinical target volumes (CTVs) that included the prostate, seminal vesicles, and pelvic lymph nodes (LNs) using Radiation Therapy Oncology Group (RTOG) consensus guidelines were contoured on the CT portion of the PET/CT by a radiation oncologist blinded to the PET findings. 68 Ga-PSMA-11 PET/CT images were analyzed by a nuclear medicine physician. PSMA-positive lesions not covered by planning volumes based on the CTVs were considered to have a major potential impact on treatment planning. Results: All patients had PSMA-positive primary prostate lesion(s). 25/73 (34%) and 7/73 (9.5%) had PSMA-positive pelvic nodal and distant metastases, respectively. The sites of nodal metastases in decreasing order of frequency were external iliac (20.5%), common iliac (13.5%), internal iliac (12.5%) obturator (12.5%), perirectal (4%), abdominal (4%), upper-diaphragm (4%), and presacral (1.5%). The median size of the nodal lesions was 6 mm (range 4-24 mm). RT planning based on the CTVs covered 69/73 (94.5%) of primary disease and 20/25 (80%) of

Implications of improved diagnostic imaging of small nodal metastases in head and neck cancer: Radiotherapy target volume transformation and dose de-escalation.

PubMed

van den Bosch, Sven; Vogel, Wouter V; Raaijmakers, Cornelis P; Dijkema, Tim; Terhaard, Chris H J; Al-Mamgani, Abrahim; Kaanders, Johannes H A M

2018-05-03

Diagnostic imaging continues to evolve, and now has unprecedented accuracy for detecting small nodal metastasis. This influences the tumor load in elective target volumes and subsequently has consequences for the radiotherapy dose required to control disease in these volumes. Small metastases that used to remain subclinical and were included in elective volumes, will nowadays be detected and included in high-dose volumes. Consequentially, high-dose volumes will more often contain low-volume disease. These target volume transformations lead to changes in the tumor burden in elective and "gross" tumor volumes with implications for the radiotherapy dose prescribed to these volumes. For head and neck tumors, nodal staging has evolved from mere palpation to combinations of high-resolution imaging modalities. A traditional nodal gross tumor volume in the neck typically had a minimum diameter of 10-15 mm, while nowadays much smaller tumor deposits are detected in lymph nodes. However, the current dose levels for elective nodal irradiation were empirically determined in the 1950s, and have not changed since. In this report the radiobiological consequences of target volume transformation caused by modern imaging of the neck are evaluated, and theoretically derived reductions of dose in radiotherapy for head and neck cancer are proposed. The concept of target volume transformation and subsequent strategies for dose adaptation applies to many other tumor types as well. Awareness of this concept may result in new strategies for target definition and selection of dose levels with the aim to provide optimal tumor control with less toxicity. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Analysis of FET-PET imaging for target volume definition in patients with gliomas treated with conformal radiotherapy.

PubMed

Rieken, Stefan; Habermehl, Daniel; Giesel, Frederik L; Hoffmann, Christoph; Burger, Ute; Rief, Harald; Welzel, Thomas; Haberkorn, Uwe; Debus, Jürgen; Combs, Stephanie E

2013-12-01

Modern radiotherapy (RT) techniques such as stereotactic RT, intensity-modulated RT, or particle irradiation allow local dose escalation with simultaneous sparing of critical organs. Several trials are currently investigating their benefit in glioma reirradiation and boost irradiation. Target volume definition is of critical importance especially when steep dose gradient techniques are employed. In this manuscript we investigate the impact of O-(2-(F-18)fluoroethyl)-l-tyrosine-positron emission tomography/computer tomography (FET-PET/CT) on target volume definition in low and high grade glioma patients undergoing either first or re-irradiation with particles. We investigated volumetric size and uniformity of magnetic resonance imaging (MRI)- vs. FET-PET/CT-derived gross tumor volumes (GTVs) and planning target volumes (PTVs) of 41 glioma patients. Clinical cases are presented to demonstrate potential benefits of integrating FET-PET/CT-planning into daily routine. Integrating FET-uptake into the delineation of GTVs yields larger volumes. Combined modality-derived PTVs are significantly enlarged in high grade glioma patients and in case of primary RT. The congruence of MRI and FET signals for the identification of glioma GTVs is poor with mean uniformity indices of 0.39. MRI-based PTVs miss 17% of FET-PET/CT-based GTVs. Non significant alterations were detected in low grade glioma patients and in those undergoing reirradiation. Target volume definition for malignant gliomas during initial RT may yield significantly differing results depending upon the imaging modality, which the contouring process is based upon. The integration of both MRI and FET-PET/CT may help to improve GTV coverage by avoiding larger incongruences between physical and biological imaging techniques. In low grade gliomas and in cases of reirradiation, more studies are needed in order to investigate a potential benefit of FET-PET/CT for planning of RT. Copyright © 2013 Elsevier Ireland Ltd. All

Variations of target volume definition and daily target volume localization in stereotactic body radiotherapy for early-stage non–small cell lung cancer patients under abdominal compression

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

Han, Chunhui, E-mail: chan@coh.org; Sampath, Sagus; Schultheisss, Timothy E.

We aimed to compare gross tumor volumes (GTV) in 3-dimensional computed tomography (3DCT) simulation and daily cone beam CT (CBCT) with the internal target volume (ITV) in 4-dimensional CT (4DCT) simulation in stereotactic body radiotherapy (SBRT) treatment of patients with early-stage non–small cell lung cancer (NSCLC) under abdominal compression. We retrospectively selected 10 patients with NSCLC who received image-guided SBRT treatments under abdominal compression with daily CBCT imaging. GTVs were contoured as visible gross tumor on the planning 3DCT and daily CBCT, and ITVs were contoured using maximum intensity projection (MIP) images of the planning 4DCT. Daily CBCTs were registeredmore » with 3DCT and MIP images by matching of bony landmarks in the thoracic region to evaluate interfractional GTV position variations. Relative to MIP-based ITVs, the average 3DCT-based GTV volume was 66.3 ± 17.1% (range: 37.5% to 92.0%) (p < 0.01 in paired t-test), and the average CBCT-based GTV volume was 90.0 ± 6.7% (daily range: 75.7% to 107.1%) (p = 0.02). Based on bony anatomy matching, the center-of-mass coordinates for CBCT-based GTVs had maximum absolute shift of 2.4 mm (left-right), 7.0 mm (anterior-posterior [AP]), and 5.2 mm (superior-inferior [SI]) relative to the MIP-based ITV. CBCT-based GTVs had average overlapping ratio of 81.3 ± 11.2% (range: 45.1% to 98.9%) with the MIP-based ITV, and 57.7 ± 13.7% (range: 35.1% to 83.2%) with the 3DCT-based GTV. Even with abdominal compression, both 3DCT simulations and daily CBCT scans significantly underestimated the full range of tumor motion. In daily image-guided patient setup corrections, automatic bony anatomy-based image registration could lead to target misalignment. Soft tissue-based image registration should be performed for accurate treatment delivery.« less

SU-F-T-394: Impact of PTV Margins With Taking Into Account Shape Variation On IMRT Plans For Prostate Cancer

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

Hirose, T; Arimura, H; Oga, S

2016-06-15

Purpose: The purpose of this study was to investigate the impact of planning target volume (PTV) margins with taking into consideration clinical target volume (CTV) shape variations on treatment plans of intensity modulated radiation therapy (IMRT) for prostate cancer. Methods: The systematic errors and the random errors for patient setup errors in right-left (RL), anterior-posterior (AP), and superior-inferior (SI) directions were obtained from data of 20 patients, and those for CTV shape variations were calculated from 10 patients, who were weekly scanned using cone beam computed tomography (CBCT). The setup error was defined as the difference in prostate centers betweenmore » planning CT and CBCT images after bone-based registrations. CTV shape variations of high, intermediate and low risk CTVs were calculated for each patient from variances of interfractional shape variations on each vertex of three-dimensional CTV point distributions, which were manually obtained from CTV contours on the CBCT images. PTV margins were calculated using the setup errors with and without CTV shape variations for each risk CTV. Six treatment plans were retrospectively made by using the PTV margins with and without CTV shape variations for the three risk CTVs of 5 test patients. Furthermore, the treatment plans were applied to CBCT images for investigating the impact of shape variations on PTV margins. Results: The percentages of population to cover with the PTV, which satisfies the CTV D98 of 95%, with and without the shape variations were 89.7% and 74.4% for high risk, 89.7% and 76.9% for intermediate risk, 84.6% and 76.9% for low risk, respectively. Conclusion: PTV margins taking into account CTV shape variation provide significant improvement of applicable percentage of population (P < 0.05). This study suggested that CTV shape variation should be taken consideration into determination of the PTV margins.« less

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

Eley, J; Mehta, M; Molitoris, J

Purpose: The purpose of this study was to propose a method to implement arc therapy that is compatible with existing particle therapy systems having gantries and pencil-beam scanning capacities. Furthermore, we sought to demonstrate expected benefits of this method for selected clival chordoma patients. Methods: We propose that a desired particle arc treatment plan can be discretized into a finite number of fixed beams and that only one (or a subset) of these beams be delivered in any single treatment fraction; the target should receive uniform dose during each fraction. For 3 clival-chordoma patients, robust-optimized, scanned proton beams were simulatedmore » to deliver 78 Gy (RBE) to clinical target volumes (CTVs), using either a single-field plan with a posterior-anterior (PA) beam or a discrete-arc plan with 16 beams that were equally spaced throughout a 360-degree axial arc. Dose-volume metrics were compared with emphasis on the brainstem, since risk of radiation necrosis there can often restrict application of tumoricidal doses for chordomas. Results: The mean volume of brainstem receiving a dose of 60 Gy (RBE) or higher (V60Gy) was 10.3±0.9 cm{sup 3} for the single-field plan and 4.7±1.8 cm{sup 3} for the discrete-arc plan, a reduction of 55% in favor of arcs. The mean dose to the brainstem was also reduced using arcs, by 18%, while the maximum dose was nearly identical for both methods. For the whole brain, V60Gy was reduced by 23%, in favor of arcs. Mean dose to the CTVs were nearly identical for both strategies, within 0.3%. Conclusion: Discrete arc treatments can be implemented using existing scanned particle-beam facilities. Aside from the physical advantages, the biological uncertainties of particle therapy, particularly high in the distal edge, can be reduced by arc therapy via rotational smearing, which may be of benefit for tumors near the brainstem.« less

Use of volume-targeted non-invasive bilevel positive airway pressure ventilation in a patient with amyotrophic lateral sclerosis*,**

PubMed Central

Diaz-Abad, Montserrat; Brown, John Edward

2014-01-01

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease in which most patients die of respiratory failure. Although volume-targeted non-invasive bilevel positive airway pressure (BPAP) ventilation has been studied in patients with chronic respiratory failure of various etiologies, its use in ALS has not been reported. We present the case of a 66-year-old woman with ALS and respiratory failure treated with volume-targeted BPAP ventilation for 15 weeks. Weekly data downloads showed that disease progression was associated with increased respiratory muscle weakness, decreased spontaneous breathing, and increased use of non-invasive positive pressure ventilation, whereas tidal volume and minute ventilation remained relatively constant. PMID:25210968

Head and Neck Margin Reduction With Adaptive Radiation Therapy: Robustness of Treatment Plans Against Anatomy Changes

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

Kranen, Simon van; Hamming-Vrieze, Olga; Wolf, Annelisa

Purpose: We set out to investigate loss of target coverage from anatomy changes in head and neck cancer patients as a function of applied safety margins and to verify a cone beam computed tomography (CBCT)–based adaptive strategy with an average patient anatomy to overcome possible target underdosage. Methods and Materials: For 19 oropharyngeal cancer patients, volumetric modulated arc therapy treatment plans (2 arcs; simultaneous integrated boost, 70 and 54.25 Gy; 35 fractions) were automatically optimized with uniform clinical target volume (CTV)–to–planning target volume margins of 5, 3, and 0 mm. We applied b-spline CBCT–to–computed tomography (CT) deformable registration to allow recalculation ofmore » the dose on modified CT scans (planning CT deformed to daily CBCT following online positioning) and dose accumulation in the planning CT scan. Patients with deviations in primary or elective CTV coverage >2 Gy were identified as candidates for adaptive replanning. For these patients, a single adaptive intervention was simulated with an average anatomy from the first 10 fractions. Results: Margin reduction from 5 mm to 3 mm to 0 mm generally led to an organ-at-risk (OAR) mean dose (D{sub mean}) sparing of approximately 1 Gy/mm. CTV shrinkage was mainly seen in the elective volumes (up to 10%), likely related to weight loss. Despite online repositioning, substantial systematic errors were present (>3 mm) in lymph node CTV, the parotid glands, and the larynx. Nevertheless, the average increase in OAR dose was small: maximum of 1.2 Gy (parotid glands, D{sub mean}) for all applied margins. Loss of CTV coverage >2 Gy was found in 1, 3, and 7 of 73 CTVs, respectively. Adaptive intervention in 0-mm plans substantially improved coverage: in 5 of 7 CTVs (in 6 patients) to <2 Gy of initially planned. Conclusions: Volumetric modulated arc therapy head and neck cancer treatment plans with 5-mm margins are robust for anatomy changes and show a modest

Analysis of radiation exposure for naval units of Operation Crossroads. Volume 2. (Appendix A) target ships. Technical report

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

Weitz, R.; Thomas, C.; Klemm, J.

1982-03-03

External radiation doses are reconstructed for crews of support and target ships of Joint Task Force One at Operation CROSSROADS, 1946. Volume I describes the reconstruction methodology, which consists of modeling the radiation environment, to include the radioactivity of lagoon water, target ships, and support ship contamination; retracing ship paths through this environment; and calculating the doses to shipboard personnel. The USS RECLAIMER, a support ship, is selected as a representative ship to demonstrate this methodology. Doses for all other ships are summarized. Volume II (Appendix A) details the results for target ship personnel. Volume III (Appendix B) details themore » results for support ship personnel. Calculated doses for more than 36,000 personnel aboard support ships while at Bikini range from zero to 1.7 rem. Of those, approximately 34,000 are less than 0.5 rem. From the models provided, doses due to target ship reboarding and doses accrued after departure from Bikini can be calculated, based on the individual circumstances of exposure.« less

Clinical and anatomical guidelines in pelvic cancer contouring for radiotherapy treatment planning.

PubMed

Portaluri, Maurizio; Bambace, Santa; Perez, Celeste; Giuliano, Giuseppe; Angone, Grazia; Scialpi, Michele; Pili, Giorgio; Didonna, Vittorio; Alloro, Emira

2004-08-01

Many observations on potential inadequate coverage of tumour volume at risk in advanced cervical cancer (CC) when conventional radiation fields are used, have further substantiated by investigators using MRI, CT or lymphangiographic imaging. This work tries to obtain three dimensional margins by observing enlarged nodes in CT scans in order to improve pelvic nodal chains clinical target volumes (CTVs) drawing, and by looking for corroborative evidence in the literature for a better delineation of tumour CTV. Eleven consecutive patients (seven males, four females, mean age 62 years, range 43-78) with CT diagnosis of nodal involvement caused by pathologically proved carcinoma of the cervix (n = 2), carcinoma of the rectum (n = 2), carcinoma of the prostate (n = 2), non-Hodgkin lymphoma (n = 2), Hodgkin lymphoma (n = 1), carcinoma of the penis (n = 1) and carcinoma of the corpus uteri (n = 1) were retrospectively reviewed. Sixty CT scans with 67 enlarged pelvic nodes were reviewed in order to record the more proximal structures (muscle, bone, vessels, cutis or subcutis and other organs) to each enlarged node or group of nodes according to the four surfaces (anterior, lateral, posterior and medial) in a clockwise direction. A summary of the observations of each nodal chain and the number of occurrences of every marginal structure on axial CT slices is presented. Finally, simple guidelines are proposed. Tumour CTV should be based on individual tumour anatomy-mainly for lateral beams as it results from sagittal T2 weighted MRI images. Boundaries of pelvic nodes CTVs can be derived from observations of enlarged lymph nodes in CT scans.

Variations of target volume definition and daily target volume localization in stereotactic body radiotherapy for early-stage non-small cell lung cancer patients under abdominal compression.

PubMed

Han, Chunhui; Sampath, Sagus; Schultheisss, Timothy E; Wong, Jeffrey Y C

2017-01-01

We aimed to compare gross tumor volumes (GTV) in 3-dimensional computed tomography (3DCT) simulation and daily cone beam CT (CBCT) with the internal target volume (ITV) in 4-dimensional CT (4DCT) simulation in stereotactic body radiotherapy (SBRT) treatment of patients with early-stage non-small cell lung cancer (NSCLC) under abdominal compression. We retrospectively selected 10 patients with NSCLC who received image-guided SBRT treatments under abdominal compression with daily CBCT imaging. GTVs were contoured as visible gross tumor on the planning 3DCT and daily CBCT, and ITVs were contoured using maximum intensity projection (MIP) images of the planning 4DCT. Daily CBCTs were registered with 3DCT and MIP images by matching of bony landmarks in the thoracic region to evaluate interfractional GTV position variations. Relative to MIP-based ITVs, the average 3DCT-based GTV volume was 66.3 ± 17.1% (range: 37.5% to 92.0%) (p < 0.01 in paired t-test), and the average CBCT-based GTV volume was 90.0 ± 6.7% (daily range: 75.7% to 107.1%) (p = 0.02). Based on bony anatomy matching, the center-of-mass coordinates for CBCT-based GTVs had maximum absolute shift of 2.4 mm (left-right), 7.0 mm (anterior-posterior [AP]), and 5.2 mm (superior-inferior [SI]) relative to the MIP-based ITV. CBCT-based GTVs had average overlapping ratio of 81.3 ± 11.2% (range: 45.1% to 98.9%) with the MIP-based ITV, and 57.7 ± 13.7% (range: 35.1% to 83.2%) with the 3DCT-based GTV. Even with abdominal compression, both 3DCT simulations and daily CBCT scans significantly underestimated the full range of tumor motion. In daily image-guided patient setup corrections, automatic bony anatomy-based image registration could lead to target misalignment. Soft tissue-based image registration should be performed for accurate treatment delivery. Copyright © 2017 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

Impact of Node Negative Target Volume Delineation on Contralateral Parotid Gland Dose Sparing Using IMRT in Head and Neck Cancer.

PubMed

Magnuson, William J; Urban, Erich; Bayliss, R Adam; Harari, Paul M

2015-06-01

There is considerable practice variation in treatment of the node negative (N0) contralateral neck in patients with head and neck cancer. In this study, we examined the impact of N0 neck target delineation volume on radiation dose to the contralateral parotid gland. Following institutional review board approval, 12 patients with head and neck cancer were studied. All had indications for treatment of the N0 neck, such as midline base of tongue or soft palate extension or advanced ipsilateral nodal disease. The N0 neck volumes were created using the Radiation Therapy Oncology Group head and neck contouring atlas. The physician-drawn N0 neck clinical target volume (CTV) was expanded by 25% to 200% to generate volume variation, followed by a 3-mm planning target volume (PTV) expansion. Surrounding organs at risk were contoured and complete intensity-modulated radiation therapy plans were generated for each N0 volume expansion. The median N0 target volume drawn by the radiation oncologist measured 93 cm(3) (range 71-145). Volumetric expansion of the N0 CTV by 25% to 200% increased the resultant mean dose to the contralateral parotid gland by 1.4 to 8.5 Gray (Gy). For example, a 4.1-mm increase in the N0 neck CTV translated to a 2.0-Gy dose increase to the parotid, 7.4 mm to a 4.5 Gy dose increase, and 12.5 mm to an 8.5 Gy dose increase, respectively. The treatment volume designated for the N0 neck has profound impact on resultant dose to the contralateral parotid gland. Variations of up to 15 mm are routine across physicians in target contouring, reflecting individual preference and training expertise. Depending on the availability of immobilization and image guidance techniques, experts commonly recommend 3 to 10 mm margin expansions to generate the PTV. Careful attention to the original volume of the N0 neck CTV, as well as expansion margins, is important in achieving effective contralateral gland sparing to reduce the resultant xerostomia and dysguesia that may ensue

A New Suggestion for the Radiation Target Volume After a Subtotal Gastrectomy in Patients With Stomach Cancer

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

Nam, Heerim; Lim, Do Hoon; Kim, Sung

2008-06-01

Purpose: To compare treatment results between the use of two different radiation fields including and excluding remnant stomach and suggest new target volumes excluding remnant stomach after subtotal gastrectomy (STG) in patients with stomach cancer. Methods and Materials: We retrospectively analyzed 291 patients treated with adjuvant chemoradiotherapy after STG and D2 dissection at the Samsung Medical Center, Seoul, South Korea. Eighty-three patients registered from 1995 to 1997 underwent irradiation according to the INT 0116 protocol that recommended the inclusion of remnant stomach within the target volume (Group A). After this period, we excluded remnant stomach from the target volume formore » 208 patients (Group B). Median follow-up was 67 months. Results: Treatment failure developed in 93 patients (32.0%). Local and regional recurrence rates for Group A vs. Group B were 10.8% vs. 5.3% (p = not significant) and 9.6% vs. 6.3% (p = not significant), and recurrence rates for remnant stomach were 7.2% vs. 1.4% (p = 0.018), respectively. Overall and disease-free survival rates were not different between the two groups. Grade 3 or 4 vomiting and diarrhea developed more frequently in Group A than Group B (4.8% vs. 1.4% and 6.0% vs. 1.9%, respectively; p = 0.012; p < 0.001). Conclusion: Exclusion of remnant stomach from the radiation field had no effect on failure rates or survival, and a low complication rate occurred in patients treated excluding remnant stomach. We suggest that remnant stomach be excluded from the radiation target volume for patients with stomach cancer who undergo STG and D2 dissection.« less

Performance of Leak Compensation in All-Age ICU Ventilators During Volume-Targeted Neonatal Ventilation: A Lung Model Study.

PubMed

Itagaki, Taiga; Bennett, Desmond J; Chenelle, Christopher T; Fisher, Daniel F; Kacmarek, Robert M

2017-01-01

Volume-targeted ventilation is increasingly used in low birthweight infants because of the potential for reducing volutrauma and avoiding hypocapnea. However, it is not known what level of air leak is acceptable during neonatal volume-targeted ventilation when leak compensation is activated concurrently. Four ICU ventilators (Servo-i, PB980, V500, and Avea) were compared in available invasive volume-targeted ventilation modes (pressure control continuous spontaneous ventilation [PC-CSV] and pressure control continuous mandatory ventilation [PC-CMV]). The Servo-i and PB980 were tested with (+) and without (-) their proximal flow sensor. The V500 and Avea were tested with their proximal flow sensor as indicated by their manufacturers. An ASL 5000 lung model was used to simulate 4 neonatal scenarios (body weight 0.5, 1, 2, and 4 kg). The ASL 5000 was ventilated via an endotracheal tube with 3 different leaks. Two minutes of data were collected after each change in leak level, and the asynchrony index was calculated. Tidal volume (V T ) before and after the change in leak was assessed. The differences in delivered V T between before and after the change in leak were within ±5% in all scenarios with the PB980 (-/+) and V500. With the Servo-i (-/+), baseline V T was ≥10% greater than set V T during PC-CSV, and delivered V T markedly changed with leak. The Avea demonstrated persistent high V T in all leak scenarios. Across all ventilators, the median asynchrony index was 1% (interquartile range 0-27%) in PC-CSV and 1.8% (0-45%) in PC-CMV. The median asynchrony index was significantly higher in the Servo-i (-/+) than in the PB980 (-/+) and V500 in 1 and 2 kg scenarios during PC-CSV and PC-CMV. The PB980 and V500 were the only ventilators to acclimate to all leak scenarios and achieve targeted V T . Further clinical investigation is needed to validate the use of leak compensation during neonatal volume-targeted ventilation. Copyright © 2017 by Daedalus Enterprises.

Utilizing 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) to define suspected nonenhancing tumor for radiation therapy planning of glioblastoma.

PubMed

Hayes, Aimee R; Jayamanne, Dasantha; Hsiao, Edward; Schembri, Geoffrey P; Bailey, Dale L; Roach, Paul J; Khasraw, Mustafa; Newey, Allison; Wheeler, Helen R; Back, Michael

2018-01-31

The authors sought to evaluate the impact of 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) on radiation therapy planning for patients diagnosed with glioblastoma (GBM) and the presence of suspected nonenhancing tumors compared with standard magnetic resonance imaging (MRI). Patients with GBM and contrast-enhanced MRI scans showing regions suspicious of nonenhancing tumor underwent postoperative FET-PET before commencing radiation therapy. Two clinical target volumes (CTVs) were created using pre- and postoperative MRI: MRI fluid-attenuated inversion recovery (FLAIR) sequences (CTV FLAIR ) and MRI contrast sequences with an expansion on the surgical cavity (CTV Sx ). FET-PET was used to create biological tumor volumes (BTVs) by encompassing FET-avid regions, forming BTV FLAIR and BTV Sx . Volumetric analyses were conducted between CTVs and respective BTVs using Wilcoxon signed-rank tests. The volume increase with addition of FET was analyzed with respect to BTV FLAIR and BTV Sx . Presence of focal gadolinium contrast enhancement within previously nonenhancing tumor or within the FET-avid region was noted on MRI scans at 1 and 3 months after radiation therapy. Twenty-six patients were identified retrospectively from our database, of whom 24 had demonstrable FET uptake. The median CTV FLAIR , CTV Sx , BTV FLAIR , and BTV Sx were 57.1 mL (range, 1.1-217.4), 83.6 mL (range, 27.2-275.8), 62.8 mL (range, 1.1-307.3), and 94.7 mL (range, 27.2-285.5), respectively. When FET-PET was used, there was a mean increase in volume of 26.8% from CTV FLAIR to BTV FLAIR and 20.6% from CTV Sx to BTV Sx . A statistically significant difference was noted on Wilcoxon signed-rank test when assessing volumetric change between CTV FLAIR and BTV FLAIR (P < .0001) and CTV Sx and BTV Sx (P < .0001). Six of 24 patients (25%) with FET avidity before radiation therapy showed focal gadolinium enhancement within the radiation therapy portal. FET-PET may help improve delineation of

Intravesical markers for delineation of target volume during external focal irradiation of bladder carcinomas.

PubMed

Hulshof, Maarten C C M; van Andel, George; Bel, Arjen; Gangel, Pieter; van de Kamer, Jeroen B

2007-07-01

A clip forceps was developed which can insert markers at the border of a bladder tumour through a rigid cystoscope. This technique proved to be simple and safe and is of help for delineation of the target volume during CT simulation for focal boost irradiation of bladder cancer.

SU-E-T-578: On Definition of Minimum and Maximum Dose for Target Volume

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

Gong, Y; Yu, J; Xiao, Y

Purpose: This study aims to investigate the impact of different minimum and maximum dose definitions in radiotherapy treatment plan quality evaluation criteria by using tumor control probability (TCP) models. Methods: Dosimetric criteria used in RTOG 1308 protocol are used in the investigation. RTOG 1308 is a phase III randomized trial comparing overall survival after photon versus proton chemoradiotherapy for inoperable stage II-IIIB NSCLC. The prescription dose for planning target volume (PTV) is 70Gy. Maximum dose (Dmax) should not exceed 84Gy and minimum dose (Dmin) should not go below 59.5Gy in order for the plan to be “per protocol” (satisfactory).A mathematicalmore » model that simulates the characteristics of PTV dose volume histogram (DVH) curve with normalized volume is built. The Dmax and Dmin are noted as percentage volumes Dη% and D(100-δ)%, with η and d ranging from 0 to 3.5. The model includes three straight line sections and goes through four points: D95%= 70Gy, Dη%= 84Gy, D(100-δ)%= 59.5 Gy, and D100%= 0Gy. For each set of η and δ, the TCP value is calculated using the inhomogeneously irradiated tumor logistic model with D50= 74.5Gy and γ50=3.52. Results: TCP varies within 0.9% with η; and δ values between 0 and 1. With η and η varies between 0 and 2, TCP change was up to 2.4%. With η and δ variations from 0 to 3.5, maximum of 8.3% TCP difference is seen. Conclusion: When defined maximum and minimum volume varied more than 2%, significant TCP variations were seen. It is recommended less than 2% volume used in definition of Dmax or Dmin for target dosimetric evaluation criteria. This project was supported by NIH grants U10CA180868, U10CA180822, U24CA180803, U24CA12014 and PA CURE Grant.« less

P04.02 Analysis of 18F-DOPA PET imaging for target volume definition in patients with recurrent glioblastoma treated with proton therapy

PubMed Central

Amelio, D.; Scartoni, D.; Palucci, A.; Vennarini, S.; Giacomelli, I.; Lemoine, S.; Donner, D.; Farace, P.; Chierichetti, F.; Amichetti, M.

2017-01-01

Abstract Introduction: Target volume definition is of critical relevance when re-irradiation is delivered and steep dose gradient irradiation techniques, such as proton therapy (PT), are employed. Aim of the study is to investigate the impact of 18F-DOPA on target volume contouring in recurrent glioblastoma (rGBM) patients (pts) undergoing re-irradiation with PT. MATERIAL AND METHODS: We investigated the differences in volume and relationship of magnetic resonance imaging (MRI)- vs. DOPA PET-derived gross tumor volumes (GTVs) of 14 rGBM pts re-irradiated with PT between January and November 2016. All pts had been previously treated with photon radiotherapy (60 Gy) with concomitant and adjuvant temozolomide. All the pts received morphological MRI with contrast enhancement medium administration and 18F-DOPA PET-CT study. We used the pathological distribution of 18F-DOPA in brain tissue to identify the so-called Biological Tumor Volume (BTV). Such areas were assessed using a tumor to normal brain ratio > 2. Moreover, any area of contrast enhancement on MRI was used to identify the MRI-based GTV (MRGTV). Definitive GTV included MRGTV plus BTV. Clinical target volume was generated by adding to GTV a 3-mm uniform margin manually corrected in proximity of anatomical barriers. CTV was expanded by 4 mm to create planning target volume. All pts received 36 GyRBE in 18 fractions. Mean values of differently delineated GTVs were compared each other by paired Student’s t-test; p < 0.05 was considered significant. To further compare MRGTV and BTV, the overlapping (MRGTV ^ BTV) and the composite (MRGTV U BTV) volumes were calculated, and a concordance index (CI) was defined as the ratio between the overlap and composite volumes. Results: MRGTV (mean 14.9 ± 14.5 cc) was larger than BTV (mean 10.9 ± 9.8 cc) although this difference was not statistically significant. The composite volume (mean 20.9 ± 14.7 cc) was significantly larger than each single volume (p < 0

Validation of a 4D-PET Maximum Intensity Projection for Delineation of an Internal Target Volume

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

Callahan, Jason, E-mail: jason.callahan@petermac.org; Kron, Tomas; Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne

2013-07-15

Purpose: The delineation of internal target volumes (ITVs) in radiation therapy of lung tumors is currently performed by use of either free-breathing (FB) {sup 18}F-fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET/CT) or 4-dimensional (4D)-CT maximum intensity projection (MIP). In this report we validate the use of 4D-PET-MIP for the delineation of target volumes in both a phantom and in patients. Methods and Materials: A phantom with 3 hollow spheres was prepared surrounded by air then water. The spheres and water background were filled with a mixture of {sup 18}F and radiographic contrast medium. A 4D-PET/CT scan was performed of the phantom whilemore » moving in 4 different breathing patterns using a programmable motion device. Nine patients with an FDG-avid lung tumor who underwent FB and 4D-PET/CT and >5 mm of tumor motion were included for analysis. The 3 spheres and patient lesions were contoured by 2 contouring methods (40% of maximum and PET edge) on the FB-PET, FB-CT, 4D-PET, 4D-PET-MIP, and 4D-CT-MIP. The concordance between the different contoured volumes was calculated using a Dice coefficient (DC). The difference in lung tumor volumes between FB-PET and 4D-PET volumes was also measured. Results: The average DC in the phantom using 40% and PET edge, respectively, was lowest for FB-PET/CT (DCAir = 0.72/0.67, DCBackground 0.63/0.62) and highest for 4D-PET/CT-MIP (DCAir = 0.84/0.83, DCBackground = 0.78/0.73). The average DC in the 9 patients using 40% and PET edge, respectively, was also lowest for FB-PET/CT (DC = 0.45/0.44) and highest for 4D-PET/CT-MIP (DC = 0.72/0.73). In the 9 lesions, the target volumes of the FB-PET using 40% and PET edge, respectively, were on average 40% and 45% smaller than the 4D-PET-MIP. Conclusion: A 4D-PET-MIP produces volumes with the highest concordance with 4D-CT-MIP across multiple breathing patterns and lesion sizes in both a phantom and among patients. Freebreathing PET/CT consistently

Facial Contouring by Targeted Restoration of Facial Fat Compartment Volume: The Midface.

PubMed

Wang, Wenjin; Xie, Yun; Huang, Ru-Lin; Zhou, Jia; Tanja, Herrler; Zhao, Peijuan; Cheng, Chen; Zhou, Sizheng; Pu, Lee L Q; Li, Qingfeng

2017-03-01

Recent anatomical findings have suggested that facial fat distribution is complex and changes with age. Here, the authors developed a grafting technique based on the physiologic distribution and volume changes of facial fat compartments to achieve a youthful and natural-appearing face. Forty cadaveric hemifaces were used for the dissection of fat compartments and neurovascular structures in the midface area. Seventy-eight patients were treated for cheek atrophy using the authors' targeted restoration of midface fat compartment volume. The outcome was evaluated by a two-dimensional assessment, malar lipoatrophy assessment, and a satisfaction survey. The medial and lateral parts of the deep medial cheek fat compartment were separated by a septum arising from the lateral border of the levator anguli oris muscle. The angular vein traveled between the deep medial cheek fat compartment and the buccal fat pad, 12 mm from the maxilla. A total volume of 29.3 ml of fat was grafted per cheek for each patient. A 12-month follow-up revealed an average volume augmentation rate of 27.1 percent. Pleasing and elevated anterior projection of the cheek and ameliorated nasolabial groove were still obvious by 12 months after the procedure. In total, 95.2 percent of the patients were satisfied with their results. The present study provides the anatomical and clinical basis for the concept of compartmentally based fat grafting. It allows for the restoration of facial fat volume close to the physiologic state. With this procedure, a natural and youthful facial contour could be rebuilt with a high satisfaction rate. Therapeutic, IV.

Poster - 36: Effect of Planning Target Volume Coverage on the Dose Delivered in Lung Radiotherapy

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

Dekker, Chris; Wierzbicki, Marcin

2016-08-15

Purpose: In lung radiotherapy, breathing motion may be encompassed by contouring the internal target volume (ITV). Remaining uncertainties are included in a geometrical expansion to the planning target volume (PTV). In IMRT, the treatment is then optimized until a desired PTV fraction is covered by the appropriate dose. The resulting beams often carry high fluence in the PTV margin to overcome low lung density and to generate steep dose gradients. During treatment, the high density tumour can enter the PTV margin, potentially increasing target dose. Thus, planning lung IMRT with a reduced PTV dose may still achieve the desired ITVmore » dose during treatment. Methods: A retrospective analysis was carried out with 25 IMRT plans prescribed to 63 Gy in 30 fractions. The plans were re-normalized to cover various fractions of the PTV by different isodose lines. For each case, the isocentre was moved using 125 shifts derived from all 3D combinations of 0 mm, (PTV margin - 1 mm), and PTV margin. After each shift, the dose was recomputed to approximate the delivered dose. Results and Conclusion: Our plans typically cover 95% of the PTV by 95% of the dose. Reducing the PTV covered to 94% did not significantly reduce the delivered ITV doses for (PTV margin - 1 mm) shifts. Target doses were reduced significantly for all other shifts and planning goals studied. Thus, a reduced planning goal will likely deliver the desired target dose as long as the ITV rarely enters the last mm of the PTV margin.« less

Using injectable hydrogel markers to assess resimulation for boost target volume definition in a patient undergoing whole-breast radiotherapy

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

Patel, Henal; Goyal, Sharad; Kim, Leonard, E-mail: kimlh@rutgers.edu

Several publications have recommended that patients undergoing whole-breast radiotherapy be resimulated for boost planning. The rationale for this is that the seroma may be smaller when compared with the initial simulation. However, the decision remains whether to use the earlier or later images to define an appropriate boost target volume. A patient undergoing whole-breast radiotherapy had new, injectable, temporary hydrogel fiducial markers placed 1 to 3 cm from the seroma at the time of initial simulation. The patient was resimulated 4.5 weeks later for conformal photon boost planning. Computed tomography (CT) scans acquired at the beginning and the end ofmore » whole-breast radiotherapy showed that shrinkage of the lumpectomy cavity was not matched by a corresponding reduction in the surrounding tissue volume, as demarcated by hydrogel markers. This observation called into question the usual interpretation of cavity shrinkage for boost target definition. For this patient, it was decided to define the boost target volume on the initial planning CT instead of the new CT.« less

Evaluation of potential internal target volume of liver tumors using cine-MRI

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

Akino, Yuichi, E-mail: akino@radonc.med.osaka-u.ac.jp; Oh, Ryoong-Jin; Masai, Norihisa

2014-11-01

Purpose: Four-dimensional computed tomography (4DCT) is widely used for evaluating moving tumors, including lung and liver cancers. For patients with unstable respiration, however, the 4DCT may not visualize tumor motion properly. High-speed magnetic resonance imaging (MRI) sequences (cine-MRI) permit direct visualization of respiratory motion of liver tumors without considering radiation dose exposure to patients. Here, the authors demonstrated a technique for evaluating internal target volume (ITV) with consideration of respiratory variation using cine-MRI. Methods: The authors retrospectively evaluated six patients who received stereotactic body radiotherapy (SBRT) to hepatocellular carcinoma. Before acquiring planning CT, sagittal and coronal cine-MRI images were acquiredmore » for 30 s with a frame rate of 2 frames/s. The patient immobilization was conducted under the same condition as SBRT. Planning CT images were then acquired within 15 min from cine-MRI image acquisitions, followed by a 4DCT scan. To calculate tumor motion, the motion vectors between two continuous frames of cine-MRI images were calculated for each frame using the pyramidal Lucas–Kanade method. The target contour was delineated on one frame, and each vertex of the contour was shifted and copied onto the following frame using neighboring motion vectors. 3D trajectory data were generated with the centroid of the contours on sagittal and coronal images. To evaluate the accuracy of the tracking method, the motion of clearly visible blood vessel was analyzed with the motion tracking and manual detection techniques. The target volume delineated on the 50% (end-exhale) phase of 4DCT was translated with the trajectory data, and the distribution of the occupancy probability of target volume was calculated as potential ITV (ITV {sub Potential}). The concordance between ITV {sub Potential} and ITV estimated with 4DCT (ITV {sub 4DCT}) was evaluated using the Dice’s similarity coefficient (DSC

Stereotactic ultrasound for target volume definition in a patient with prostate cancer and bilateral total hip replacement.

PubMed

Boda-Heggemann, Judit; Haneder, Stefan; Ehmann, Michael; Sihono, Dwi Seno Kuncoro; Wertz, Hansjörg; Mai, Sabine; Kegel, Stefan; Heitmann, Sigrun; von Swietochowski, Sandra; Lohr, Frank; Wenz, Frederik

2015-01-01

Target-volume definition for prostate cancer in patients with bilateral metal total hip replacements (THRs) is a challenge because of metal artifacts in the planning computed tomography (CT) scans. Magnetic resonance imaging (MRI) can be used for matching and prostate delineation; however, at a spatial and temporal distance from the planning CT, identical rectal and vesical filling is difficult to achieve. In addition, MRI may also be impaired by metal artifacts, even resulting in spatial image distortion. Here, we present a method to define prostate target volumes based on ultrasound images acquired during CT simulation and online-matched to the CT data set directly at the planning CT. A 78-year-old patient with cT2cNxM0 prostate cancer with bilateral metal THRs was referred to external beam radiation therapy. T2-weighted MRI was performed on the day of the planning CT with preparation according to a protocol for reproducible bladder and rectal filling. The planning CT was obtained with the immediate acquisition of a 3-dimensional ultrasound data set with a dedicated stereotactic ultrasound system for online intermodality image matching referenced to the isocenter by ceiling-mounted infrared cameras. MRI (offline) and ultrasound images (online) were thus both matched to the CT images for planning. Daily image guided radiation therapy (IGRT) was performed with transabdominal ultrasound and compared with cone beam CT. Because of variations in bladder and rectal filling and metal-induced image distortion in MRI, soft-tissue-based matching of the MRI to CT was not sufficient for unequivocal prostate target definition. Ultrasound-based images could be matched, and prostate, seminal vesicles, and target volumes were reliably defined. Daily IGRT could be successfully completed with transabdominal ultrasound with good accordance between cone beam CT and ultrasound. For prostate cancer patients with bilateral THRs causing artifacts in planning CTs, ultrasound referenced to

[Microscopic extensions of head and neck squamous cell carcinomas: impact for clinical target volume definition].

PubMed

Fleury, B; Thariat, J; Barnoud, R; Buiret, G; Lebreton, F; Bancel, B; Poupart, M; Devouassoux-Shisheboran, M

2014-11-01

To assess microscopic extensions of head and neck squamous cell carcinomas aiming at a proposal for target volumes of radiation therapy. Surgical specimens were prospectively analysed macroscopically and microscopically. Tumour borders were identified per macroscopic visual examination and inked on stained slides. Then microscopic implants (perineural or lymphatic involvement, or in situ carcinomas) were looked for with an optic microscope in the macroscopic healthy tissue surrounding the tumour. The maximal length from tumour border was correlated with the maximal length of macroscopically healthy tissues assessable. Twenty-one specimens were analysed and 12 were locally advanced tumours. Mean and median maximal microscopic extensions were 2.9 and 1.0mm (0-15mm), respectively. The 90th and 95th percentiles were 5 and 11mm, respectively. The ratio between healthy tissue length and maximal microscopic tumour extension was 10%. No correlation was found with tumour grade or volume. The presence of microscopic tumour was unlikely after 5mm from macroscopic tumour (≤5% of patients in this series) but should be assessed along with other histoclinical factors and particularities of tumour behaviour by anatomic site. A rigorous terminology should authorize a relevant appreciation of local risk of recurrence, particularly in adjuvant setting or for clinical target volume definition. Larger and more homogenous confirmatory series are needed. Copyright © 2014. Published by Elsevier SAS.

On the interplay effects with proton scanning beams in stage III lung cancer

PubMed Central

Li, Yupeng; Kardar, Laleh; Li, Xiaoqiang; Li, Heng; Cao, Wenhua; Chang, Joe Y.; Liao, Li; Zhu, Ronald X.; Sahoo, Narayan; Gillin, Michael; Liao, Zhongxing; Komaki, Ritsuko; Cox, James D.; Lim, Gino; Zhang, Xiaodong

2014-01-01

Purpose: To assess the dosimetric impact of interplay between spot-scanning proton beam and respiratory motion in intensity-modulated proton therapy (IMPT) for stage III lung cancer. Methods: Eleven patients were sampled from 112 patients with stage III nonsmall cell lung cancer to well represent the distribution of 112 patients in terms of target size and motion. Clinical target volumes (CTVs) and planning target volumes (PTVs) were defined according to the authors' clinical protocol. Uniform and realistic breathing patterns were considered along with regular- and hypofractionation scenarios. The dose contributed by a spot was fully calculated on the computed tomography (CT) images corresponding to the respiratory phase that the spot is delivered, and then accumulated to the reference phase of the 4DCT to generate the dynamic dose that provides an estimation of what might be delivered under the influence of interplay effect. The dynamic dose distributions at different numbers of fractions were compared with the corresponding 4D composite dose which is the equally weighted average of the doses, respectively, computed on respiratory phases of a 4DCT image set. Results: Under regular fractionation, the average and maximum differences in CTV coverage between the 4D composite and dynamic doses after delivery of all 35 fractions were no more than 0.2% and 0.9%, respectively. The maximum differences between the two dose distributions for the maximum dose to the spinal cord, heart V40, esophagus V55, and lung V20 were 1.2 Gy, 0.1%, 0.8%, and 0.4%, respectively. Although relatively large differences in single fraction, correlated with small CTVs relative to motions, were observed, the authors' biological response calculations suggested that this interfractional dose variation may have limited biological impact. Assuming a hypofractionation scenario, the differences between the 4D composite and dynamic doses were well confined even for single fraction. Conclusions: Despite

On the interplay effects with proton scanning beams in stage III lung cancer.

PubMed

Li, Yupeng; Kardar, Laleh; Li, Xiaoqiang; Li, Heng; Cao, Wenhua; Chang, Joe Y; Liao, Li; Zhu, Ronald X; Sahoo, Narayan; Gillin, Michael; Liao, Zhongxing; Komaki, Ritsuko; Cox, James D; Lim, Gino; Zhang, Xiaodong

2014-02-01

To assess the dosimetric impact of interplay between spot-scanning proton beam and respiratory motion in intensity-modulated proton therapy (IMPT) for stage III lung cancer. Eleven patients were sampled from 112 patients with stage III nonsmall cell lung cancer to well represent the distribution of 112 patients in terms of target size and motion. Clinical target volumes (CTVs) and planning target volumes (PTVs) were defined according to the authors' clinical protocol. Uniform and realistic breathing patterns were considered along with regular- and hypofractionation scenarios. The dose contributed by a spot was fully calculated on the computed tomography (CT) images corresponding to the respiratory phase that the spot is delivered, and then accumulated to the reference phase of the 4DCT to generate the dynamic dose that provides an estimation of what might be delivered under the influence of interplay effect. The dynamic dose distributions at different numbers of fractions were compared with the corresponding 4D composite dose which is the equally weighted average of the doses, respectively, computed on respiratory phases of a 4DCT image set. Under regular fractionation, the average and maximum differences in CTV coverage between the 4D composite and dynamic doses after delivery of all 35 fractions were no more than 0.2% and 0.9%, respectively. The maximum differences between the two dose distributions for the maximum dose to the spinal cord, heart V40, esophagus V55, and lung V20 were 1.2 Gy, 0.1%, 0.8%, and 0.4%, respectively. Although relatively large differences in single fraction, correlated with small CTVs relative to motions, were observed, the authors' biological response calculations suggested that this interfractional dose variation may have limited biological impact. Assuming a hypofractionation scenario, the differences between the 4D composite and dynamic doses were well confined even for single fraction. Despite the presence of interplay effect, the

The application of positron emission tomography/computed tomography in radiation treatment planning: effect on gross target volume definition and treatment management.

PubMed

Iğdem, S; Alço, G; Ercan, T; Unalan, B; Kara, B; Geceer, G; Akman, C; Zengin, F O; Atilla, S; Okkan, S

2010-04-01

To analyse the effect of the use of molecular imaging on gross target volume (GTV) definition and treatment management. Fifty patients with various solid tumours who underwent positron emission tomography (PET)/computed tomography (CT) simulation for radiotherapy planning from 2006 to 2008 were enrolled in this study. First, F-18 fluorodeoxyglucose (FDG)-PET and CT scans of the treatment site in the treatment position and then a whole body scan were carried out with a dedicated PET/CT scanner and fused thereafter. FDG-avid primary tumour and lymph nodes were included into the GTV. A multidisciplinary team defined the target volume, and contouring was carried out by a radiation oncologist using visual methods. To compare the PET/CT-based volumes with CT-based volumes, contours were drawn on CT-only data with the help of site-specific radiologists who were blind to the PET/CT results after a median time of 7 months. In general, our PET/CT volumes were larger than our CT-based volumes. This difference was significant in patients with head and neck cancers. Major changes (> or =25%) in GTV delineation were observed in 44% of patients. In 16% of cases, PET/CT detected incidental second primaries and metastatic disease, changing the treatment strategy from curative to palliative. Integrating functional imaging with FDG-PET/CT into the radiotherapy planning process resulted in major changes in a significant proportion of our patients. An interdisciplinary approach between imaging and radiation oncology departments is essential in defining the target volumes. Copyright 2010 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Delineation of Internal Mammary Nodal Target Volumes in Breast Cancer Radiation Therapy

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

Jethwa, Krishan R.; Kahila, Mohamed M.; Hunt, Katie N.

Purpose: The optimal clinical target volume for internal mammary (IM) node irradiation is uncertain in an era of increasingly conformal volume-based treatment planning for breast cancer. We mapped the location of gross internal mammary lymph node (IMN) metastases to identify areas at highest risk of harboring occult disease. Methods and Materials: Patients with axial imaging of IMN disease were identified from a breast cancer registry. The IMN location was transferred onto the corresponding anatomic position on representative axial computed tomography images of a patient in the treatment position and compared with consensus group guidelines of IMN target delineation. Results: Themore » IMN location in 67 patients with 130 IMN metastases was mapped. The location was in the first 3 intercostal spaces in 102 of 130 nodal metastases (78%), whereas 18 of 130 IMNs (14%) were located caudal to the third intercostal space and 10 of 130 IMNs (8%) were located cranial to the first intercostal space. Of the 102 nodal metastases within the first 3 intercostal spaces, 54 (53%) were located within the Radiation Therapy Oncology Group consensus volume. Relative to the IM vessels, 19 nodal metastases (19%) were located medially with a mean distance of 2.2 mm (SD, 2.9 mm) whereas 29 (28%) were located laterally with a mean distance of 3.6 mm (SD, 2.5 mm). Ninety percent of lymph nodes within the first 3 intercostal spaces would have been encompassed within a 4-mm medial and lateral expansion on the IM vessels. Conclusions: In women with indications for elective IMN irradiation, a 4-mm medial and lateral expansion on the IM vessels may be appropriate. In women with known IMN involvement, cranial extension to the confluence of the IM vein with the brachiocephalic vein with or without caudal extension to the fourth or fifth interspace may be considered provided that normal tissue constraints are met.« less

Target location after deep cerebral biopsies using low-volume air injection in 75 patients. Results and technical note.

PubMed

Poca, Maria A; Martínez-Ricarte, Francisco-Ramon; Gándara, Dario F; Coscojuela, Pilar; Martínez-Sáez, Elena; Sahuquillo, Juan

2017-10-01

Stereotactic biopsy is a minimally invasive technique that allows brain tissue samples to be obtained with low risk. Classically, different techniques have been used to identify the biopsy site after surgery. To describe a technique to identify the precise location of the target in the postoperative CT scan using the injection of a low volume of air into the biopsy cannula. Seventy-five biopsies were performed in 65 adults and 10 children (40 males and 35 females, median age 51 years). Frame-based biopsy was performed in 46 patients, while frameless biopsy was performed in the remaining 29 patients. In both systems, after brain specimens had been collected and with the biopsy needle tip in the center of the target, a small volume of air (median 0.7 cm 3 ) was injected into the site. A follow-up CT scan was performed in all patients. Intracranial air in the selected target was present in 69 patients (92%). No air was observed in two patients (air volume administered in these 2 cases was below 0.7 cm 3 ), while in the remaining four patients blood content was observed in the target. The diagnostic yield in this series was 97.3%. No complications were found to be associated with intracranial air injection in any of the 75 patients who underwent this procedure. The air-injection maneuver proposed for use in stereotactic biopsies of intracranial mass lesions is a safe and reliable technique that allows the exact biopsy site to be located without any related complications.

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

Zhang, JY; Hong, DL

Purpose: The purpose of this study is to investigate the patient set-up error and interfraction target coverage in cervical cancer using image-guided adaptive radiotherapy (IGART) with cone-beam computed tomography (CBCT). Methods: Twenty cervical cancer patients undergoing intensity modulated radiotherapy (IMRT) were randomly selected. All patients were matched to the isocenter using laser with the skin markers. Three dimensional CBCT projections were acquired by the Varian Truebeam treatment system. Set-up errors were evaluated by radiation oncologists, after CBCT correction. The clinical target volume (CTV) was delineated on each CBCT, and the planning target volume (PTV) coverage of each CBCT-CTVs was analyzed.more » Results: A total of 152 CBCT scans were acquired from twenty cervical cancer patients, the mean set-up errors in the longitudinal, vertical, and lateral direction were 3.57, 2.74 and 2.5mm respectively, without CBCT corrections. After corrections, these were decreased to 1.83, 1.44 and 0.97mm. For the target coverage, CBCT-CTV coverage without CBCT correction was 94% (143/152), and 98% (149/152) with correction. Conclusion: Use of CBCT verfication to measure patient setup errors could be applied to improve the treatment accuracy. In addition, the set-up error corrections significantly improve the CTV coverage for cervical cancer patients.« less

Effects of online cone-beam computed tomography with active breath control in determining planning target volume during accelerated partial breast irradiation.

PubMed

Li, Y; Zhong, R; Wang, X; Ai, P; Henderson, F; Chen, N; Luo, F

2017-04-01

To test if active breath control during cone-beam computed tomography (CBCT) could improve planning target volume during accelerated partial breast radiotherapy for breast cancer. Patients who were more than 40 years old, underwent breast-conserving dissection and planned for accelerated partial breast irradiation, and with postoperative staging limited to T1-2 N0 M0, or postoperative staging T2 lesion no larger than 3cm with a negative surgical margin greater than 2mm were enrolled. Patients with lobular carcinoma or extensive ductal carcinoma in situ were excluded. CBCT images were obtained pre-correction, post-correction and post-treatment. Set-up errors were recorded at left-right, anterior-posterior and superior-inferior directions. The differences between these CBCT images, as well as calculated radiation doses, were compared between patients with active breath control or free breathing. Forty patients were enrolled, among them 25 had active breath control. A total of 836 CBCT images were obtained for analysis. CBCT significantly reduced planning target volume. However, active breath control did not show significant benefit in decreasing planning target volume margin and the doses of organ-at-risk when compared to free breathing. CBCT, but not active breath control, could reduce planning target volume during accelerated partial breast irradiation. Copyright © 2017 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Synovial tissue volume: a treatment target in knee osteoarthritis (OA).

PubMed

O'Neill, Terence W; Parkes, Matthew J; Maricar, Nasimah; Marjanovic, Elizabeth J; Hodgson, Richard; Gait, Andrew D; Cootes, Timothy F; Hutchinson, Charles E; Felson, David T

2016-01-01

Synovitis occurring frequently in osteoarthritis (OA) may be a targeted outcome. There are no data examining whether synovitis changes following intra-articular intervention. Persons aged 40 years and older with painful knee OA participated in an open label trial of intra-articular steroid therapy. At all time points they completed the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. They had a contrast-enhanced (CE) MRI immediately prior to an intra-articular steroid injection with a repeat scan within 20 days. Response status was assessed using the Osteoarthritis Research Society International (OARSI) response criteria. OARSI responders were followed until their pain relapsed either within 20% of baseline or 6 months, shortly after which a third MRI was performed. Synovial tissue volume (STV) was measured on postcontrast knee images. We looked at changes in the STV and in pain, and their association. 120 subjects with preinjection and postinjection CE MRI were followed. Their mean age was 62.3 years (SD=10.3) and 62 (52%) were women. The median time between injection and follow-up scan was 8 days (IQR 7-14 days). 85/120 (71%) were OARSI responders. Pain decreased (mean change in KOOS=+23.9; 95% CI 20.1 to 27.8, p<0.001) following steroid injection, as did mean STV (mean change=-1071 mm(3); 95% CI -1839 mm(3) to -303 mm(3), p=0.01). Of the 80 who returned for a third MRI, pain relapsed in 57, and in the 48 of those with MRI data, STV increased between follow-up and final visit (+1220 mm(3); 95% CI 25 mm(3) to 2414 mm(3), p=0.05). 23 were persistent responders at 6 months and, in these, STV did not increase (mean change=-202 mm(3); 95% CI -2008 mm(3) to 1604 mm(3), p=0.83). Controlling for variation over time, there was a significant association between synovitis volume and KOOS pain (b coefficient-change in KOOS pain score per 1000 mm(3) change in STV=-1.13; 95% CI -1.87 to -0.39, p=0.003), although STV accounted for only a small proportion of

Potential implications of the bystander effect on TCP and EUD when considering target volume dose heterogeneity.

PubMed

Balderson, Michael J; Kirkby, Charles

2015-01-01

In light of in vitro evidence suggesting that radiation-induced bystander effects may enhance non-local cell killing, there is potential for impact on radiotherapy treatment planning paradigms such as the goal of delivering a uniform dose throughout the clinical target volume (CTV). This work applies a bystander effect model to calculate equivalent uniform dose (EUD) and tumor control probability (TCP) for external beam prostate treatment and compares the results with a more common model where local response is dictated exclusively by local absorbed dose. The broad assumptions applied in the bystander effect model are intended to place an upper limit on the extent of the results in a clinical context. EUD and TCP of a prostate cancer target volume under conditions of increasing dose heterogeneity were calculated using two models: One incorporating bystander effects derived from previously published in vitro bystander data ( McMahon et al. 2012 , 2013a); and one using a common linear-quadratic (LQ) response that relies exclusively on local absorbed dose. Dose through the CTV was modelled as a normal distribution, where the degree of heterogeneity was then dictated by changing the standard deviation (SD). Also, a representative clinical dose distribution was examined as cold (low dose) sub-volumes were systematically introduced. The bystander model suggests a moderate degree of dose heterogeneity throughout a target volume will yield as good or better outcome compared to a uniform dose in terms of EUD and TCP. For a typical intermediate risk prostate prescription of 78 Gy over 39 fractions maxima in EUD and TCP as a function of increasing SD occurred at SD ∼ 5 Gy. The plots only dropped below the uniform dose values for SD ∼ 10 Gy, almost 13% of the prescribed dose. Small, but potentially significant differences in the outcome metrics between the models were identified in the clinically-derived dose distribution as cold sub-volumes were introduced. In terms of

Volume comparison of radiofrequency ablation at 3- and 5-cm target volumes for four different radiofrequency generators: MR volumetry in an open 1-T MRI system versus macroscopic measurement.

PubMed

Rathke, Hendrik; Hamm, Bernd; Guettler, Felix; Lohneis, Philipp; Stroux, Andrea; Suttmeyer, Britta; Jonczyk, Martin; Teichgräber, Ulf; de Bucourt, Maximilian

2015-12-01

In a patient, it is usually not macroscopically possible to estimate the non-viable volume induced by radiofrequency ablation (RFA) after the procedure. The purpose of this study was to use an ex vivo bovine liver model to perform magnetic resonance (MR) volumetry of the visible tissue signal change induced by RFA and to correlate the MR measurement with the actual macroscopic volume measured in the dissected specimens. Sixty-four liver specimens cut from 16 bovine livers were ablated under constant simulated, close physiological conditions with target volumes set to 14.14 ml (3-cm lesion) and 65.45 ml (5-cm lesion). Four commercially available radiofrequency (RF) systems were tested (n=16 for each system; n=8 for 3 cm and n=8 for 5 cm). A T1-weighted turbo spin echo (TSE) sequence with inversion recovery and a proton-density (PD)-weighted TSE sequence were acquired in a 1.0-T open magnetic resonance imaging (MRI) system. After manual dissection, actual macroscopic ablation diameters were measured and volumes calculated. MR volumetry was performed using a semiautomatic software tool. To validate the correctness and feasibility of the volume formula in macroscopic measurements, MR multiplanar reformation diameter measurements with subsequent volume calculation and semiautomatic MR volumes were correlated. Semiautomatic MR volumetry yielded smaller volumes than manual measurement after dissection, irrespective of RF system used, target lesion size, and MR sequence. For the 3-cm lesion, only 43.3% (T1) and 41.5% (PD) of the entire necrosis are detectable. For the 5-cm lesion, only 40.8% (T1) and 37.2% (PD) are visualized in MRI directly after intervention. The correlation between semiautomatic MR volumes and calculated MR volumes was 0.888 for the T1-weighted sequence and 0.875 for the PD sequence. After correlation of semiautomatic MR volumes and calculated MR volumes, it seems reasonable to use the respective volume formula for macroscopic volume calculation

International guideline for the delineation of the clinical target volumes (CTV) for nasopharyngeal carcinoma.

PubMed

Lee, Anne W; Ng, Wai Tong; Pan, Jian Ji; Poh, Sharon S; Ahn, Yong Chan; AlHussain, Hussain; Corry, June; Grau, Cai; Grégoire, Vincent; Harrington, Kevin J; Hu, Chao Su; Kwong, Dora L; Langendijk, Johannes A; Le, Quynh Thu; Lee, Nancy Y; Lin, Jin Ching; Lu, Tai Xiang; Mendenhall, William M; O'Sullivan, Brian; Ozyar, Enis; Peters, Lester J; Rosenthal, David I; Soong, Yoke Lim; Tao, Yungan; Yom, Sue S; Wee, Joseph T

2018-01-01

Target delineation in nasopharyngeal carcinoma (NPC) often proves challenging because of the notoriously narrow therapeutic margin. High doses are needed to achieve optimal levels of tumour control, and dosimetric inadequacy remains one of the most important independent factors affecting treatment outcome. A review of the available literature addressing the natural behaviour of NPC and correlation between clinical and pathological aspects of the disease was conducted. Existing international guidelines as well as published protocols specified by clinical trials on contouring of clinical target volumes (CTV) were compared. This information was then summarized into a preliminary draft guideline which was then circulated to international experts in the field for exchange of opinions and subsequent voting on areas with the greatest controversies. Common areas of uncertainty and variation in practices among experts experienced in radiation therapy for NPC were elucidated. Iterative revisions were made based on extensive discussion and final voting on controversial areas by the expert panel, to formulate the recommendations on contouring of CTV based on optimal geometric expansion and anatomical editing for those structures with substantial risk of microscopic infiltration. Through this comprehensive review of available evidence and best practices at major institutions, as well as interactive exchange of vast experience by international experts, this set of consensus guidelines has been developed to provide a practical reference for appropriate contouring to ensure optimal target coverage. However, the final decision on the treatment volumes should be based on full consideration of individual patients' factors and facilities of an individual centre (including the quality of imaging methods and the precision of treatment delivery). Copyright © 2017 Elsevier B.V. All rights reserved.

FDG-PET-based differential uptake volume histograms: a possible approach towards definition of biological target volumes.

PubMed

Devic, Slobodan; Mohammed, Huriyyah; Tomic, Nada; Aldelaijan, Saad; De Blois, François; Seuntjens, Jan; Lehnert, Shirley; Faria, Sergio

2016-06-01

Integration of fluorine-18 fludeoxyglucose ((18)F-FDG)-positron emission tomography (PET) functional data into conventional anatomically based gross tumour volume delineation may lead to optimization of dose to biological target volumes (BTV) in radiotherapy. We describe a method for defining tumour subvolumes using (18)F-FDG-PET data, based on the decomposition of differential uptake volume histograms (dUVHs). For 27 patients with histopathologically proven non-small-cell lung carcinoma (NSCLC), background uptake values were sampled within the healthy lung contralateral to a tumour in those image slices containing tumour and then scaled by the ratio of mass densities between the healthy lung and tumour. Signal-to-background (S/B) uptake values within volumes of interest encompassing the tumour were used to reconstruct the dUVHs. These were subsequently decomposed into the minimum number of analytical functions (in the form of differential uptake values as a function of S/B) that yielded acceptable net fits, as assessed by χ(2) values. Six subvolumes consistently emerged from the fitted dUVHs over the sampled volume of interest on PET images. Based on the assumption that each function used to decompose the dUVH may correspond to a single subvolume, the intersection between the two adjacent functions could be interpreted as a threshold value that differentiates them. Assuming that the first two subvolumes spread over the tumour boundary, we concentrated on four subvolumes with the highest uptake values, and their S/B thresholds [mean ± standard deviation (SD)] were 2.88 ± 0.98, 4.05 ± 1.55, 5.48 ± 2.06 and 7.34 ± 2.89 for adenocarcinoma, 3.01 ± 0.71, 4.40 ± 0.91, 5.99 ± 1.31 and 8.17 ± 2.42 for large-cell carcinoma and 4.54 ± 2.11, 6.46 ± 2.43, 8.87 ± 5.37 and 12.11 ± 7.28 for squamous cell carcinoma, respectively. (18)F-FDG-based PET data may potentially be used to identify BTV within the tumour in

High-Frequency Jet Ventilation for Complete Target Immobilization and Reduction of Planning Target Volume in Stereotactic High Single-Dose Irradiation of Stage I Non-Small Cell Lung Cancer and Lung Metastases

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

Fritz, Peter, E-mail: p.h.fritz@t-online.d; Kraus, Hans-Joerg; Muehlnickel, Werner

2010-09-01

Purpose: To demonstrate the feasibility of complete target immobilization by means of high-frequency jet ventilation (HFJV); and to show that the saving of planning target volume (PTV) on the stereotactic body radiation therapy (SBRT) under HFJV, compared with SBRT with respiratory motion, can be predicted with reliable accuracy by computed tomography (CT) scans at peak inspiration phase. Methods and Materials: A comparison regarding different methods for defining the PTV was carried out in 22 patients with tumors that clearly moved with respiration. A movement span of the gross tumor volume (GTV) was defined by fusing respiration-correlated CT scans. The PTVmore » enclosed the GTV positions with a safety margin throughout the breathing cycle. To create a PTV from CT scans acquired under HFJV, the same margins were drawn around the immobilized target. In addition, peak inspiration phase CT images (PIP-CTs) were used to approximate a target immobilized by HFJV. Results: The resulting HFJV-PTVs were between 11.6% and 45.4% smaller than the baseline values calculated as respiration-correlated CT-PTVs (median volume reduction, 25.4%). Tentative planning by means of PIP-CT PTVs predicted that in 19 of 22 patients, use of HFJV would lead to a reduction in volume of {>=}20%. Using this threshold yielded a positive predictive value of 0.89, as well as a sensitivity of 0.94 and a specificity of 0.5. Conclusions: In all patients, SBRT under HFJV provided a reliable immobilization of the GTVs and achieved a reduction in PTVs, regardless of patient compliance. Tentative planning facilitated the selection of patients who could better undergo radiation in respiratory standstill, both with greater accuracy and lung protection.« less

Utilization of cone-beam CT for offline evaluation of target volume coverage during prostate image-guided radiotherapy based on bony anatomy alignment.

PubMed

Paluska, Petr; Hanus, Josef; Sefrova, Jana; Rouskova, Lucie; Grepl, Jakub; Jansa, Jan; Kasaova, Linda; Hodek, Miroslav; Zouhar, Milan; Vosmik, Milan; Petera, Jiri

2012-01-01

To assess target volume coverage during prostate image-guided radiotherapy based on bony anatomy alignment and to assess possibility of safety margin reduction. Implementation of IGRT should influence safety margins. Utilization of cone-beam CT provides current 3D anatomic information directly in irradiation position. Such information enables reconstruction of the actual dose distribution. Seventeen prostate patients were treated with daily bony anatomy image-guidance. Cone-beam CT (CBCT) scans were acquired once a week immediately after bony anatomy alignment. After the prostate, seminal vesicles, rectum and bladder were contoured, the delivered dose distribution was reconstructed. Target dose coverage was evaluated by the proportion of the CTV encompassed by the 95% isodose. Original plans employed a 1 cm safety margin. Alternative plans assuming a smaller 7 mm margin between CTV and PTV were evaluated in the same way. Rectal and bladder volumes were compared with the initial ones. Rectal and bladder volumes irradiated with doses higher than 75 Gy, 70 Gy, 60 Gy, 50 Gy and 40 Gy were analyzed. In 12% of reconstructed plans the prostate coverage was not sufficient. The prostate underdosage was observed in 5 patients. Coverage of seminal vesicles was not satisfactory in 3% of plans. Most of the target underdosage corresponded to excessive rectal or bladder filling. Evaluation of alternative plans assuming a smaller 7 mm margin revealed 22% and 11% of plans where prostate and seminal vesicles coverage, respectively, was compromised. These were distributed over 8 and 7 patients, respectively. Sufficient dose coverage of target volumes was not achieved for all patients. Reducing of safety margin is not acceptable. Initial rectal and bladder volumes cannot be considered representative for subsequent treatment.

Long-term Outcomes of Temporal Hollowing Augmentation by Targeted Volume Restoration of Fat Compartments in Chinese Adults.

PubMed

Huang, Ru-Lin; Xie, Yun; Wang, Wenjin; Tan, Pohching; Li, Qingfeng

2018-04-19

Previous anatomical and clinical studies have suggested that targeted restoration of the volume and distribution of fat compartments using appropriate cannula entry sites and injection planes is an excellent fat-grafting technique for facial contouring and hand rejuvenation. To perform subjective and objective evaluations of the safe and effective profile of the targeted fat-grafting technique for temporal hollowing augmentation. In a retrospective cohort study, a total of 96 consecutive patients with temporal hollowing were treated at the Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai, China, with the targeted fat-grafting technique from January 1, 2009, to January 1, 2017. The safety and efficacy profile of this technique was evaluated by the following methods: (1) a quantitative measurement of fat-graft survival and temporal augmentation rates by using 3-dimensional laser scanning, (2) a subjective assessment using a satisfaction survey and the Hollowness Severity Rating Scale (grades range from 0-3, with higher grades representing more hollowness), and (3) the complication rate. Of the 96 study patients, 94 (97.9%) were women and the mean (SD) age was 34.4 (7.4) years. Of the 142 autologous fat-grafting procedures performed, the mean (SD) total follow-up time was 16.3 (3.2) months, with a mean (SD) of 1.5 (0.7) procedures performed. The mean (SD) baseline volume requirement per temple for each patient was 12.8 (4.8) mL, and the total volume of the fat graft per temple was 17.8 (7.5) mL. Quantitative analysis revealed that the mean (SD) total augmentation volume per temple was 11.7 (3.0) mL, the total survival rate of the fat grafts was 65.7% (12.6%), and total augmentation rate of hollowness was 91.4% (23.4%). Subjective analysis revealed that all patients showed an improved appearance after fat grafting, and 142 temples (74.0%) exhibited clinical improvement by more than 2 grades. In all, 88 patients (91.7%) were

Potential dosimetric benefits of adaptive tumor tracking over the internal target volume concept for stereotactic body radiation therapy of pancreatic cancer.

PubMed

Karava, Konstantina; Ehrbar, Stefanie; Riesterer, Oliver; Roesch, Johannes; Glatz, Stefan; Klöck, Stephan; Guckenberger, Matthias; Tanadini-Lang, Stephanie

2017-11-09

Radiotherapy for pancreatic cancer has two major challenges: (I) the tumor is adjacent to several critical organs and, (II) the mobility of both, the tumor and its surrounding organs at risk (OARs). A treatment planning study simulating stereotactic body radiation therapy (SBRT) for pancreatic tumors with both the internal target volume (ITV) concept and the tumor tracking approach was performed. The two respiratory motion-management techniques were compared in terms of doses to the target volume and organs at risk. Two volumetric-modulated arc therapy (VMAT) treatment plans (5 × 5 Gy) were created for each of the 12 previously treated pancreatic cancer patients, one using the ITV concept and one the tumor tracking approach. To better evaluate the overall dose delivered to the moving tumor volume, 4D dose calculations were performed on four-dimensional computed tomography (4DCT) scans. The resulting planning target volume (PTV) size for each technique was analyzed. Target and OAR dose parameters were reported and analyzed for both 3D and 4D dose calculation. Tumor motion ranged from 1.3 to 11.2 mm. Tracking led to a reduction of PTV size (max. 39.2%) accompanied with significant better tumor coverage (p<0.05, paired Wilcoxon signed rank test) both in 3D and 4D dose calculations and improved organ at risk sparing. Especially for duodenum, stomach and liver, the mean dose was significantly reduced (p<0.05) with tracking for 3D and 4D dose calculations. By using an adaptive tumor tracking approach for respiratory-induced pancreatic motion management, a significant reduction in PTV size can be achieved, which subsequently facilitates treatment planning, and improves organ dose sparing. The dosimetric benefit of tumor tracking is organ and patient-specific.

A new functional method to choose the target lobe for lung volume reduction in emphysema - comparison with the conventional densitometric method.

PubMed

Hetzel, Juergen; Boeckeler, Michael; Horger, Marius; Ehab, Ahmed; Kloth, Christopher; Wagner, Robert; Freitag, Lutz; Slebos, Dirk-Jan; Lewis, Richard Alexander; Haentschel, Maik

2017-01-01

Lung volume reduction (LVR) improves breathing mechanics by reducing hyperinflation. Lobar selection usually focuses on choosing the most destroyed emphysematous lobes as seen on an inspiratory CT scan. However, it has never been shown to what extent these densitometric CT parameters predict the least deflation of an individual lobe during expiration. The addition of expiratory CT analysis allows measurement of the extent of lobar air trapping and could therefore provide additional functional information for choice of potential treatment targets. To determine lobar vital capacity/lobar total capacity (LVC/LTC) as a functional parameter for lobar air trapping using on an inspiratory and expiratory CT scan. To compare lobar selection by LVC/LTC with the established morphological CT density parameters. 36 patients referred for endoscopic LVR were studied. LVC/LTC, defined as delta volume over maximum volume of a lobe, was calculated using inspiratory and expiratory CT scans. The CT morphological parameters of mean lung density (MLD), low attenuation volume (LAV), and 15th percentile of Hounsfield units (15%P) were determined on an inspiratory CT scan for each lobe. We compared and correlated LVC/LTC with MLD, LAV, and 15%P. There was a weak correlation between the functional parameter LVC/LTC and all inspiratory densitometric parameters. Target lobe selection using lowest lobar deflation (lowest LVC/LTC) correlated with target lobe selection based on lowest MLD in 18 patients (50.0%), with the highest LAV in 13 patients (36.1%), and with the lowest 15%P in 12 patients (33.3%). CT-based measurement of deflation (LVC/LTC) as a functional parameter correlates weakly with all densitometric CT parameters on a lobar level. Therefore, morphological criteria based on inspiratory CT densitometry partially reflect the deflation of particular lung lobes, and may be of limited value as a sole predictor for target lobe selection in LVR.

SU-E-T-287: Dose Verification On the Variation of Target Volume and Organ at Risk in Preradiation Chemotherapy IMRT for Nasopharyngeal Cancer

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

Zhang, X; Kong, L; Wang, J

2015-06-15

Purpose: To quantify the target volume and organ at risk of nasopharyngeal carcinoma (NPC) patients with preradiation chemotherapy based on CT scanned during intensity-modulated radiotherapy (IMRT), and recalculate the dose distribution. Methods: Seven patients with NPC and preradiation chemotherapy, treated with IMRT (35 to 37 fractions) were reviewed. Repeat CT scanning was required to all of the patients during the radiotherapy, and the number of repeat CTs varies from 2 to 6. The plan CT and repeat CT were generated by different CT scanner. To ensure crespectively on the same IMPT plan. The real dose distribution was calculated by deformablemore » registration and weighted method in Raystation (v 4.5.1). The fraction of each dose is based on radiotherapy record. The volumetric and dose differences among these images were calculated for nascIpharyngeal tumor and retro-pharyngeal lymph nodes (GTV-NX), neck lymph nodes(GTV-ND), and parotid glands. Results: The volume variation in GTV-NX from CT1 to CT2 was 1.15±3.79%, and in GTV-LN −0.23±4.93%. The volume variation in left parotid from CT1 to CT2 was −6.79±11.91%, and in right parotid −3.92±8.80%. In patient 2, the left parotid volume were decreased remarkably, as a Result, the V30 and V40 of it were increased as well. Conclusion: The target volume of patients with NPC varied lightly during IMRT. It shows that preradiation chemotherapy can control the target volume variation and perform a good dose repeatability. Also, the decreasing volume of parotid in some patient might increase the dose of it, which might course potential complications.« less

The potential advantages of (18)FDG PET/CT-based target volume delineation in radiotherapy planning of head and neck cancer.

PubMed

Moule, Russell N; Kayani, Irfan; Moinuddin, Syed A; Meer, Khalda; Lemon, Catherine; Goodchild, Kathleen; Saunders, Michele I

2010-11-01

This study investigated two fixed threshold methods to delineate the target volume using (18)FDG PET/CT before and during a course of radical radiotherapy in locally advanced squamous cell carcinoma of the head and neck. Patients were enrolled into the study between March 2006 and May 2008. (18)FDG PET/CT scans were carried out 72h prior to the start of radiotherapy and then at 10, 44 and 66Gy. Functional volumes were delineated according to the SUV Cut Off (SUVCO) (2.5, 3.0, 3.5, and 4.0bwg/ml) and percentage of the SUVmax (30%, 35%, 40%, 45%, and 50%) thresholds. The background (18)FDG uptake and the SUVmax within the volumes were also assessed. Primary and lymph node volumes for the eight patients significantly reduced with each increase in the delineation threshold (for example 2.5-3.0bwg/ml SUVCO) compared to the baseline threshold at each imaging point. There was a significant reduction in the volume (p⩽0.0001-0.01) after 36Gy compared to the 0Gy by the SUVCO method. There was a negative correlation between the SUVmax within the primary and lymph node volumes and delivered radiation dose (p⩽0.0001-0.011) but no difference in the SUV within the background reference region. The volumes delineated by the PTSUVmax method increased with the increase in the delivered radiation dose after 36Gy because the SUVmax within the region of interest used to define the edge of the volume was equal or less than the background (18)FDG uptake and the software was unable to effectively differentiate between tumour and background uptake. The changes in the target volumes delineated by the SUVCO method were less susceptible to background (18)FDG uptake compared to those delineated by the PTSUVmax and may be more helpful in radiotherapy planning. The best method and threshold have still to be determined within institutions, both nationally and internationally. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Dosimetric Advantages of Midventilation Compared With Internal Target Volume for Radiation Therapy of Pancreatic Cancer

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

Lens, Eelco, E-mail: e.lens@amc.uva.nl; Horst, Astrid van der; Versteijne, Eva

2015-07-01

Purpose: The midventilation (midV) approach can be used to take respiratory-induced pancreatic tumor motion into account during radiation therapy. In this study, the dosimetric consequences for organs at risk and tumor coverage of using a midV approach compared with using an internal target volume (ITV) were investigated. Methods and Materials: For each of the 18 patients, 2 treatment plans (25 × 2.0 Gy) were created, 1 using an ITV and 1 using a midV approach. The midV dose distribution was blurred using the respiratory-induced motion from 4-dimensional computed tomography. The resulting planning target volume (PTV) coverage for this blurred dosemore » distribution was analyzed; PTV coverage was required to be at least V{sub 95%} >98%. In addition, the change in PTV size and the changes in V{sub 10Gy}, V{sub 20Gy}, V{sub 30Gy}, V{sub 40Gy}, D{sub mean} and D{sub 2cc} for the stomach and for the duodenum were analyzed; differences were tested for significance using the Wilcoxon signed-rank test. Results: Using a midV approach resulted in sufficient target coverage. A highly significant PTV size reduction of 13.9% (P<.001) was observed. Also, all dose parameters for the stomach and duodenum, except the D{sub 2cc} of the duodenum, improved significantly (P≤.002). Conclusions: By using the midV approach to account for respiratory-induced tumor motion, a significant PTV reduction and significant dose reductions to the stomach and to the duodenum can be achieved when irradiating pancreatic tumors.« less

A new approach to delineating lymph node target volumes for post-operative radiotherapy in gastric cancer: A phase II trial.

PubMed

Haijun, Yu; Qiuji, Wu; Zhenming, Fu; Yong, Huang; Zhengkai, Liao; Conghua, Xie; Yunfeng, Zhou; Yahua, Zhong

2015-08-01

In the context of gastric cancer, lymph node target volume delineation for post-operative radiotherapy is currently built on the traditional system of dividing the stomach and 2-D treatment methods. Here, we have proposed a new delineation approach with irradiation indications for lymph node stations. Its safety and efficacy were evaluated in a phase II clinical trial. Fifty-four gastric cancer patients with D2 lymph node dissection received 2 cycles of FOLFOX4. They subsequently received concurrent chemoradiotherapy (45 Gy at 1.8 Gy per fraction, 5 fractions per week for 5 weeks) with a 5-fluorouracil/leucovorin regimen, followed by 4 additional FOLFOX4 cycles. The target volume included the remnant stomach, anastomosis site, tumor bed, and regional lymph nodes selected through our new approach by taking gastric arteries as references. The most common grade 3-4 adverse event was neutropenia (14.8%). Neutropenia, anemia, and nausea were common grade 1-2 toxicities. No treatment-related deaths occurred during treatment. The 3-year overall, disease-free, and locoregional recurrence-free survival rates were 81.6%, 70.2%, and 91.1%, respectively. Eight patients developed peritoneal or distant metastases. Using our new approach and irradiation indications, delineation of the target volume of post-operative lymph node stations was feasible and well tolerated after D2 resection in patients with gastric cancer. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Radiotherapy planning for glioblastoma based on a tumor growth model: improving target volume delineation.

PubMed

Unkelbach, Jan; Menze, Bjoern H; Konukoglu, Ender; Dittmann, Florian; Le, Matthieu; Ayache, Nicholas; Shih, Helen A

2014-02-07

Glioblastoma differ from many other tumors in the sense that they grow infiltratively into the brain tissue instead of forming a solid tumor mass with a defined boundary. Only the part of the tumor with high tumor cell density can be localized through imaging directly. In contrast, brain tissue infiltrated by tumor cells at low density appears normal on current imaging modalities. In current clinical practice, a uniform margin, typically two centimeters, is applied to account for microscopic spread of disease that is not directly assessable through imaging. The current treatment planning procedure can potentially be improved by accounting for the anisotropy of tumor growth, which arises from different factors: anatomical barriers such as the falx cerebri represent boundaries for migrating tumor cells. In addition, tumor cells primarily spread in white matter and infiltrate gray matter at lower rate. We investigate the use of a phenomenological tumor growth model for treatment planning. The model is based on the Fisher-Kolmogorov equation, which formalizes these growth characteristics and estimates the spatial distribution of tumor cells in normal appearing regions of the brain. The target volume for radiotherapy planning can be defined as an isoline of the simulated tumor cell density. This paper analyzes the model with respect to implications for target volume definition and identifies its most critical components. A retrospective study involving ten glioblastoma patients treated at our institution has been performed. To illustrate the main findings of the study, a detailed case study is presented for a glioblastoma located close to the falx. In this situation, the falx represents a boundary for migrating tumor cells, whereas the corpus callosum provides a route for the tumor to spread to the contralateral hemisphere. We further discuss the sensitivity of the model with respect to the input parameters. Correct segmentation of the brain appears to be the most

Radiotherapy planning for glioblastoma based on a tumor growth model: improving target volume delineation

NASA Astrophysics Data System (ADS)

Unkelbach, Jan; Menze, Bjoern H.; Konukoglu, Ender; Dittmann, Florian; Le, Matthieu; Ayache, Nicholas; Shih, Helen A.

2014-02-01

Glioblastoma differ from many other tumors in the sense that they grow infiltratively into the brain tissue instead of forming a solid tumor mass with a defined boundary. Only the part of the tumor with high tumor cell density can be localized through imaging directly. In contrast, brain tissue infiltrated by tumor cells at low density appears normal on current imaging modalities. In current clinical practice, a uniform margin, typically two centimeters, is applied to account for microscopic spread of disease that is not directly assessable through imaging. The current treatment planning procedure can potentially be improved by accounting for the anisotropy of tumor growth, which arises from different factors: anatomical barriers such as the falx cerebri represent boundaries for migrating tumor cells. In addition, tumor cells primarily spread in white matter and infiltrate gray matter at lower rate. We investigate the use of a phenomenological tumor growth model for treatment planning. The model is based on the Fisher-Kolmogorov equation, which formalizes these growth characteristics and estimates the spatial distribution of tumor cells in normal appearing regions of the brain. The target volume for radiotherapy planning can be defined as an isoline of the simulated tumor cell density. This paper analyzes the model with respect to implications for target volume definition and identifies its most critical components. A retrospective study involving ten glioblastoma patients treated at our institution has been performed. To illustrate the main findings of the study, a detailed case study is presented for a glioblastoma located close to the falx. In this situation, the falx represents a boundary for migrating tumor cells, whereas the corpus callosum provides a route for the tumor to spread to the contralateral hemisphere. We further discuss the sensitivity of the model with respect to the input parameters. Correct segmentation of the brain appears to be the most

Risk factors for radiation pneumonitis after stereotactic radiation therapy for lung tumours: clinical usefulness of the planning target volume to total lung volume ratio.

PubMed

Ueyama, Tomoko; Arimura, Takeshi; Takumi, Koji; Nakamura, Fumihiko; Higashi, Ryutaro; Ito, Soichiro; Fukukura, Yoshihiko; Umanodan, Tomokazu; Nakajo, Masanori; Koriyama, Chihaya; Yoshiura, Takashi

2018-06-01

To identify risk factors for symptomatic radiation pneumonitis (RP) after stereotactic radiation therapy (SRT) for lung tumours. We retrospectively evaluated 68 lung tumours in 63 patients treated with SRT between 2011 and 2015. RP was graded according to the National Cancer Institute-Common Terminology Criteria for Adverse Events version 4.0. SRT was delivered at 7.0-12.0 Gy per each fraction, once daily, to a total of 48-64 Gy (median, 50 Gy). Univariate analysis was performed to assess patient- and treatment-related factors, including age, sex, smoking index (SI), pulmonary function, tumour location, serum Krebs von den Lungen-6 value (KL-6), dose-volume metrics (V5, V10, V20, V30, V40 and VS5), homogeneity index of the planning target volume (PTV), PTV dose, mean lung dose (MLD), contralateral MLD and V2, PTV volume, lung volume and the PTV/lung volume ratio (PTV/Lung). Performance of PTV/Lung in predicting symptomatic RP was also analysed using receiver operating characteristic (ROC) analysis. The median follow-up period was 21 months. 10 of 63 patients (15.9%) developed symptomatic RP after SRT. On univariate analysis, V10, V20, PTV volume and PTV/Lung were significantly associated with occurrence of RP  ≥Grade 2. ROC curves indicated that symptomatic RP could be predicted using PTV/Lung [area under curve (AUC): 0.88, confidence interval (CI: 0.78-0.95), cut-off value: 1.09, sensitivity: 90.0% and specificity: 72.4%]. PTV/Lung is a good predictor of symptomatic RP after SRT. Advances in knowledge: The cases with high PTV/Lung should be carefully monitored with caution for the occurrence of RP after SRT.

SU-E-T-480: Radiobiological Dose Comparison of Single Fraction SRS, Multi-Fraction SRT and Multi-Stage SRS of Large Target Volumes Using the Linear-Quadratic Formula

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

Ding, C; Hrycushko, B; Jiang, S

2014-06-01

Purpose: To compare the radiobiological effect on large tumors and surrounding normal tissues from single fraction SRS, multi-fractionated SRT, and multi-staged SRS treatment. Methods: An anthropomorphic head phantom with a centrally located large volume target (18.2 cm{sup 3}) was scanned using a 16 slice large bore CT simulator. Scans were imported to the Multiplan treatment planning system where a total prescription dose of 20Gy was used for a single, three staged and three fractionated treatment. Cyber Knife treatment plans were inversely optimized for the target volume to achieve at least 95% coverage of the prescription dose. For the multistage plan,more » the target was segmented into three subtargets having similar volume and shape. Staged plans for individual subtargets were generated based on a planning technique where the beam MUs of the original plan on the total target volume are changed by weighting the MUs based on projected beam lengths within each subtarget. Dose matrices for each plan were export in DICOM format and used to calculate equivalent dose distributions in 2Gy fractions using an alpha beta ratio of 10 for the target and 3 for normal tissue. Results: Singe fraction SRS, multi-stage plan and multi-fractionated SRT plans had an average 2Gy dose equivalent to the target of 62.89Gy, 37.91Gy and 33.68Gy, respectively. The normal tissue within 12Gy physical dose region had an average 2Gy dose equivalent of 29.55Gy, 16.08Gy and 13.93Gy, respectively. Conclusion: The single fraction SRS plan had the largest predicted biological effect for the target and the surrounding normal tissue. The multi-stage treatment provided for a more potent biologically effect on target compared to the multi-fraction SRT treatments with less biological normal tissue than single-fraction SRS treatment.« less

Volume Transmission in Central Dopamine and Noradrenaline Neurons and Its Astroglial Targets.

PubMed

Fuxe, Kjell; Agnati, Luigi F; Marcoli, Manuela; Borroto-Escuela, Dasiel O

2015-12-01

Already in the 1960s the architecture and pharmacology of the brainstem dopamine (DA) and noradrenaline (NA) neurons with formation of vast numbers of DA and NA terminal plexa of the central nervous system (CNS) indicated that they may not only communicate via synaptic transmission. In the 1980s the theory of volume transmission (VT) was introduced as a major communication together with synaptic transmission in the CNS. VT is an extracellular and cerebrospinal fluid transmission of chemical signals like transmitters, modulators etc. moving along energy gradients making diffusion and flow of VT signals possible. VT interacts with synaptic transmission mainly through direct receptor-receptor interactions in synaptic and extrasynaptic heteroreceptor complexes and their signaling cascades. The DA and NA neurons are specialized for extrasynaptic VT at the soma-dendrtitic and terminal level. The catecholamines released target multiple DA and adrenergic subtypes on nerve cells, astroglia and microglia which are the major cell components of the trophic units building up the neural-glial networks of the CNS. DA and NA VT can modulate not only the strength of synaptic transmission but also the VT signaling of the astroglia and microglia of high relevance for neuron-glia interactions. The catecholamine VT targeting astroglia can modulate the fundamental functions of astroglia observed in neuroenergetics, in the Glymphatic system, in the central renin-angiotensin system and in the production of long-distance calcium waves. Also the astrocytic and microglial DA and adrenergic receptor subtypes mediating DA and NA VT can be significant drug targets in neurological and psychiatric disease.

The impact of PET/CT scanning on the size of target volumes, radiation exposure of organs at risk, TCP and NTCP, in the radiotherapy planning of non-small cell lung cancer.

PubMed

Vojtíšek, Radovan; Mužík, Jan; Slampa, Pavel; Budíková, Marie; Hejsek, Jaroslav; Smolák, Petr; Ferda, Jiří; Fínek, Jindřich

2014-05-01

To compare radiotherapy plans made according to CT and PET/CT and to investigate the impact of changes in target volumes on tumour control probability (TCP), normal tissue complication probability (NTCP) and the impact of PET/CT on the staging and treatment strategy. Contemporary studies have proven that PET/CT attains higher sensitivity and specificity in the diagnosis of lung cancer and also leads to higher accuracy than CT alone in the process of target volume delineation in NSCLC. Between October 2009 and March 2012, 31 patients with locally advanced NSCLC, who had been referred to radical radiotherapy were involved in our study. They all underwent planning PET/CT examination. Then we carried out two separate delineations of target volumes and two radiotherapy plans and we compared the following parameters of those plans: staging, treatment purpose, the size of GTV and PTV and the exposure of organs at risk (OAR). TCP and NTCP were also compared. PET/CT information led to a significant decrease in the sizes of target volumes, which had the impact on the radiation exposure of OARs. The reduction of target volume sizes was not reflected in the significant increase of the TCP value. We found that there is a very strong direct linear relationship between all evaluated dosimetric parameters and NTCP values of all evaluated OARs. Our study found that the use of planning PET/CT in the radiotherapy planning of NSCLC has a crucial impact on the precise determination of target volumes, more precise staging of the disease and thus also on possible changes of treatment strategy.

Influence of FDG-PET on primary nodal target volume definition for head and neck carcinomas.

PubMed

van Egmond, Sylvia L; Piscaer, Vera; Janssen, Luuk M; Stegeman, Inge; Hobbelink, Monique G; Grolman, Wilko; Terhaard, Chris H

The role of 2-[ 18 F]-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in routine diagnostic staging remains controversial. In case of discordance between FDG-PET and CT, a compromise has to be made between the risk of false positive FDG-PET and the risk of delaying appropriate salvage intervention. Second, with intensity modulated radiation therapy (IMRT), smaller radiation fields allow tissue sparing, but could also lead to more marginal failures. We retrospectively studied 283 patients with head and neck carcinoma scheduled for radiotherapy between 2002 and 2010. We analyzed the influence of FDG-PET/CT versus CT alone on defining nodal target volume definition and evaluated its long-term clinical results. Second, the location of nodal recurrences was related to the radiation regional dose distribution. In 92 patients, CT and FDG-PET, performed in mold, showed discordant results. In 33%, nodal staging was altered by FDG-PET. In 24%, FDG-PET also led to an alteration in nodal treatment, including a nodal upstage of 18% and downstage of 6%. In eight of these 92 patients, a regional recurrence occurred. Only two patients had a recurrence in the discordant node on FDG-PET and CT and both received a boost (high dose radiation). These results support the complementary value of FDG-PET/CT compared to CT alone in defining nodal target volume definition for radiotherapy of head and neck cancer.

Comparative Study With New Accuracy Metrics for Target Volume Contouring in PET Image Guided Radiation Therapy

PubMed Central

Shepherd, T; Teras, M; Beichel, RR; Boellaard, R; Bruynooghe, M; Dicken, V; Gooding, MJ; Julyan, PJ; Lee, JA; Lefèvre, S; Mix, M; Naranjo, V; Wu, X; Zaidi, H; Zeng, Z; Minn, H

2017-01-01

The impact of positron emission tomography (PET) on radiation therapy is held back by poor methods of defining functional volumes of interest. Many new software tools are being proposed for contouring target volumes but the different approaches are not adequately compared and their accuracy is poorly evaluated due to the ill-definition of ground truth. This paper compares the largest cohort to date of established, emerging and proposed PET contouring methods, in terms of accuracy and variability. We emphasize spatial accuracy and present a new metric that addresses the lack of unique ground truth. Thirty methods are used at 13 different institutions to contour functional volumes of interest in clinical PET/CT and a custom-built PET phantom representing typical problems in image guided radiotherapy. Contouring methods are grouped according to algorithmic type, level of interactivity and how they exploit structural information in hybrid images. Experiments reveal benefits of high levels of user interaction, as well as simultaneous visualization of CT images and PET gradients to guide interactive procedures. Method-wise evaluation identifies the danger of over-automation and the value of prior knowledge built into an algorithm. PMID:22692898

Changes in the planning target volume and liver volume dose based on the selected respiratory phase in respiratory-gated radiation therapy for a hepatocellular carcinoma

NASA Astrophysics Data System (ADS)

Lee, Jae-Seung; Im, In-Chul; Kang, Su-Man; Goo, Eun-Hoe; Baek, Seong-Min

2013-11-01

The aim of this study was to quantitatively analyze the changes in the planning target volume (PTV) and liver volume dose based on the respiratory phase to identify the optimal respiratory phase for respiratory-gated radiation therapy for a hepatocellular carcinoma (HCC). Based on the standardized procedure for respiratory-gated radiation therapy, we performed a 4-dimensional computed tomography simulation for 0 ˜ 90%, 30 ˜ 70%, and 40 ˜ 60% respiratory phases to assess the respiratory stability (S R ) and the defined PTV i for each respiratory phase i. A treatment plan was established, and the changes in the PTV i and dose volume of the liver were quantitatively analyzed. Most patients (91.5%) passed the respiratory stability test (S R = 0.111 ± 0.015). With standardized respiration training exercises, we were able to minimize the overall systematic error caused by irregular respiration. Furthermore, a quantitative analysis to identify the optimal respiratory phase revealed that when a short respiratory phase (40 ˜ 60%) was used, the changes in the PTV were concentrated inside the center line; thus, we were able to obtain both a PTV margin accounting for respiration and a uniform radiation dose within the PTV.

Bar coded retroreflective target

DOEpatents

Vann, Charles S.

2000-01-01

This small, inexpensive, non-contact laser sensor can detect the location of a retroreflective target in a relatively large volume and up to six degrees of position. The tracker's laser beam is formed into a plane of light which is swept across the space of interest. When the beam illuminates the retroreflector, some of the light returns to the tracker. The intensity, angle, and time of the return beam is measured to calculate the three dimensional location of the target. With three retroreflectors on the target, the locations of three points on the target are measured, enabling the calculation of all six degrees of target position. Until now, devices for three-dimensional tracking of objects in a large volume have been heavy, large, and very expensive. Because of the simplicity and unique characteristics of this tracker, it is capable of three-dimensional tracking of one to several objects in a large volume, yet it is compact, light-weight, and relatively inexpensive. Alternatively, a tracker produces a diverging laser beam which is directed towards a fixed position, and senses when a retroreflective target enters the fixed field of view. An optically bar coded target can be read by the tracker to provide information about the target. The target can be formed of a ball lens with a bar code on one end. As the target moves through the field, the ball lens causes the laser beam to scan across the bar code.

A clip-based protocol for breast boost radiotherapy provides clear target visualisation and demonstrates significant volume reduction over time

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

Lewis, Lorraine; Cox, Jennifer; Faculty of Health Sciences, University of Sydney, Sydney, New South Wales

2015-09-15

The clinical target volume (CTV) for early stage breast cancer is difficult to clearly identify on planning computed tomography (CT) scans. Surgical clips inserted around the tumour bed should help to identify the CTV, particularly if the seroma has been reabsorbed, and enable tracking of CTV changes over time. A surgical clip-based CTV delineation protocol was introduced. CTV visibility and its post-operative shrinkage pattern were assessed. The subjects were 27 early stage breast cancer patients receiving post-operative radiotherapy alone and 15 receiving post-operative chemotherapy followed by radiotherapy. The radiotherapy alone (RT/alone) group received a CT scan at median 25 daysmore » post-operatively (CT1rt) and another at 40 Gy, median 68 days (CT2rt). The chemotherapy/RT group (chemo/RT) received a CT scan at median 18 days post-operatively (CT1ch), a planning CT scan at median 126 days (CT2ch), and another at 40 Gy (CT3ch). There was no significant difference (P = 0.08) between the initial mean CTV for each cohort. The RT/alone cohort showed significant CTV volume reduction of 38.4% (P = 0.01) at 40 Gy. The Chemo/RT cohort had significantly reduced volumes between CT1ch: median 54 cm{sup 3} (4–118) and CT2ch: median 16 cm{sup 3}, (2–99), (P = 0.01), but no significant volume reduction thereafter. Surgical clips enable localisation of the post-surgical seroma for radiotherapy targeting. Most seroma shrinkage occurs early, enabling CT treatment planning to take place at 7 weeks, which is within the 9 weeks recommended to limit disease recurrence.« less

Comparison of five segmentation tools for 18F-fluoro-deoxy-glucose-positron emission tomography-based target volume definition in head and neck cancer.

PubMed

Schinagl, Dominic A X; Vogel, Wouter V; Hoffmann, Aswin L; van Dalen, Jorn A; Oyen, Wim J; Kaanders, Johannes H A M

2007-11-15

Target-volume delineation for radiation treatment to the head and neck area traditionally is based on physical examination, computed tomography (CT), and magnetic resonance imaging. Additional molecular imaging with (18)F-fluoro-deoxy-glucose (FDG)-positron emission tomography (PET) may improve definition of the gross tumor volume (GTV). In this study, five methods for tumor delineation on FDG-PET are compared with CT-based delineation. Seventy-eight patients with Stages II-IV squamous cell carcinoma of the head and neck area underwent coregistered CT and FDG-PET. The primary tumor was delineated on CT, and five PET-based GTVs were obtained: visual interpretation, applying an isocontour of a standardized uptake value of 2.5, using a fixed threshold of 40% and 50% of the maximum signal intensity, and applying an adaptive threshold based on the signal-to-background ratio. Absolute GTV volumes were compared, and overlap analyses were performed. The GTV method of applying an isocontour of a standardized uptake value of 2.5 failed to provide successful delineation in 45% of cases. For the other PET delineation methods, volume and shape of the GTV were influenced heavily by the choice of segmentation tool. On average, all threshold-based PET-GTVs were smaller than on CT. Nevertheless, PET frequently detected significant tumor extension outside the GTV delineated on CT (15-34% of PET volume). The choice of segmentation tool for target-volume definition of head and neck cancer based on FDG-PET images is not trivial because it influences both volume and shape of the resulting GTV. With adequate delineation, PET may add significantly to CT- and physical examination-based GTV definition.

Impact of case volume on outcome and performance of targeted temperature management in out-of-hospital cardiac arrest survivors.

PubMed

Lee, Seung Joon; Jeung, Kyung Woon; Lee, Byung Kook; Min, Yong Il; Park, Kyu Nam; Suh, Gil Joon; Kim, Kyung Su; Kang, Gu Hyun

2015-01-01

This study aimed to determine the effect of case volume on targeted temperature management (TTM) performance, incidence of adverse events, and neurologic outcome in comatose out-of-hospital cardiac arrest (OHCA) survivors treated with TTM. We used a Web-based, multicenter registry (Korean Hypothermia Network registry), to which 24 hospitals throughout the Republic of Korea participated to study adult (≥18 years) comatose out-of-hospital cardiac arrest patients treated with TTM between 2007 and 2012. The primary outcome was neurologic outcome at hospital discharge. The secondary outcomes were inhospital mortality, TTM performance, and adverse events. We extracted propensity-matched cohorts to control for bias. Multivariate logistic regression analysis was performed to assess independent risk factors for neurologic outcome. A total of 901 patients were included in this study; 544 (60.4%) survived to hospital discharge, and 248 (27.5%) were discharged with good neurologic outcome. The high-volume hospitals initiated TTM significantly earlier and had lower rates of hyperglycemia, bleeding, hypotension, and rebound hyperthermia. However, neurologic outcome and inhospital mortality were comparable between high-volume (27.7% and 44.6%, respectively) and low-volume hospitals (21.1% and 40.5%) in the propensity-matched cohorts. The adjusted odds ratio for the high-volume hospitals compared with low-volume hospitals was 1.506 (95% confidence interval, 0.875-2.592) for poor neurologic outcome. Higher TTM case volume was significantly associated with early initiation of TTM and lower incidence of adverse events. However, case volume had no association with neurologic outcome and inhospital mortality. Copyright © 2014 Elsevier Inc. All rights reserved.

Dosimetric evaluation of anatomical changes during treatment to identify criteria for adaptive radiotherapy in oesophageal cancer patients.

PubMed

Nyeng, Tine Bisballe; Nordsmark, Marianne; Hoffmann, Lone

2015-01-01

Some oesophageal cancer patients undergoing chemotherapy and concomitant radiotherapy (chemoRT) show large interfractional anatomical changes during treatment. These changes may modify the dose delivered to the target and organs at risk (OARs). The aim of the presenwt study was to investigate the dosimetric consequences of anatomical changes during treatment to obtain criteria for an adaptive RT decision support system. Twenty-nine patients were treated with chemoRT for oesophageal and gastro-oesophageal junction cancer and set up according to daily cone beam computed tomography (CBCTs) scans. All patients had an additional replanning CT scan at median fraction number 10 (9-14), which was deformably registered to the original planning CT. Gross tumour volumes (GTVs), clinical target volumes (CTVs) and OARs were transferred to the additional CT and corrected by an exwperienced physician. Treatment plans were recalculated and dose to targets and OARs was evaluated. Treatment was adapted if the volume receiving 95% of the prescribed dose (V95%) coverage of CTV decreased > 1% or planning target volume (PTV) decreased by > 3%. In total, nine adaptive events were observed: All nine were triggered by PTV V95% decrease > 3% [median 11% (5-41%)] and six of these were additionally triggered by CTV V95% decrease > 1% [median 5% (2-35%)]. The largest discrepancies were caused by interfractional baseline or amplitude shifts in diaphragm position (n = 5). Mediastinal (n = 6), oesophageal (n = 6) and bowel filling changes (n = 2) caused the remainder of the changes. For patients with dosimetric changes exceeding the adaptation limits, the discrepancies were confirmed by inspecting the daily CBCTs. In 31% of all patients, heart V30Gy increased more than 2% (maximum 5%). Only minor changes in lung dose or liver dose were seen. Target coverage throughout the course of chemoRT treatment is compromised in some patients due to interfractional anatomical changes. Dose to the heart may

Planning magnetic resonance imaging for prostate cancer intensity-modulated radiation therapy: Impact on target volumes, radiotherapy dose and androgen deprivation administration.

PubMed

Horsley, Patrick J; Aherne, Noel J; Edwards, Grace V; Benjamin, Linus C; Wilcox, Shea W; McLachlan, Craig S; Assareh, Hassan; Welshman, Richard; McKay, Michael J; Shakespeare, Thomas P

2015-03-01

Magnetic resonance imaging (MRI) scans are increasingly utilized for radiotherapy planning to contour the primary tumors of patients undergoing intensity-modulated radiation therapy (IMRT). These scans may also demonstrate cancer extent and may affect the treatment plan. We assessed the impact of planning MRI detection of extracapsular extension, seminal vesicle invasion, or adjacent organ invasion on the staging, target volume delineation, doses, and hormonal therapy of patients with prostate cancer undergoing IMRT. The records of 509 consecutive patients with planning MRI scans being treated with IMRT for prostate cancer between January 2010 and July 2012 were retrospectively reviewed. Tumor staging and treatment plans before and after MRI were compared. Of the 509 patients, 103 (20%) were upstaged and 44 (9%) were migrated to a higher risk category as a result of findings at MRI. In 94 of 509 patients (18%), the MRI findings altered management. Ninety-four of 509 patients (18%) had a change to their clinical target volume (CTV) or treatment technique, and in 41 of 509 patients (8%) the duration of hormone therapy was changed because of MRI findings. The use of radiotherapy planning MRI altered CTV design, dose and/or duration of androgen deprivation in 18% of patients in this large, single institution series of men planned for dose-escalated prostate IMRT. This has substantial implications for radiotherapy target volumes and doses, as well as duration of androgen deprivation. Further research is required to investigate whether newer MRI techniques can simultaneously fulfill staging and radiotherapy contouring roles. © 2014 Wiley Publishing Asia Pty Ltd.

Target volume and artifact evaluation of a new data-driven 4D CT.

PubMed

Martin, Rachael; Pan, Tinsu

Four-dimensional computed tomography (4D CT) is often used to define the internal gross target volume (IGTV) for radiation therapy of lung cancer. Traditionally, this technique requires the use of an external motion surrogate; however, a new image, data-driven 4D CT, has become available. This study aims to describe this data-driven 4D CT and compare target contours created with it to those created using standard 4D CT. Cine CT data of 35 patients undergoing stereotactic body radiation therapy were collected and sorted into phases using standard and data-driven 4D CT. IGTV contours were drawn using a semiautomated method on maximum intensity projection images of both 4D CT methods. Errors resulting from reproducibility of the method were characterized. A comparison of phase image artifacts was made using a normalized cross-correlation method that assigned a score from +1 (data-driven "better") to -1 (standard "better"). The volume difference between the data-driven and standard IGTVs was not significant (data driven was 2.1 ± 1.0% smaller, P = .08). The Dice similarity coefficient showed good similarity between the contours (0.949 ± 0.006). The mean surface separation was 0.4 ± 0.1 mm and the Hausdorff distance was 3.1 ± 0.4 mm. An average artifact score of +0.37 indicated that the data-driven method had significantly fewer and/or less severe artifacts than the standard method (P = 1.5 × 10 -5 for difference from 0). On average, the difference between IGTVs derived from data-driven and standard 4D CT was not clinically relevant or statistically significant, suggesting data-driven 4D CT can be used in place of standard 4D CT without adjustments to IGTVs. The relatively large differences in some patients were usually attributed to limitations in automatic contouring or differences in artifacts. Artifact reduction and setup simplicity suggest a clinical advantage to data-driven 4D CT. Published by Elsevier Inc.

Technology transfer from NASA to targeted industries, volume 2

NASA Technical Reports Server (NTRS)

Mccain, Wayne; Schroer, Bernard J.; Souder, William E.; Spann, Mary S.; Watters, Harry; Ziemke, M. Carl

1993-01-01

This volume contains the following materials to support Volume 1: (1) Survey of Metal Fabrication Industry in Alabama; (2) Survey of Electronics Manufacturing/Assembly Industry in Alabama; (3) Apparel Modular Manufacturing Simulators; (4) Synopsis of a Stereolithography Project; (5) Transferring Modular Manufacturing Technology to an Apparel Firm; (6) Letters of Support; (7) Fact Sheets; (8) Publications; and (9) One Stop Access to NASA Technology Brochure.

Will weight loss cause significant dosimetric changes of target volumes and organs at risk in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy?

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

Chen, Chuanben; Fei, Zhaodong; Chen, Lisha

This study aimed to quantify dosimetric effects of weight loss for nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). Overall, 25 patients with NPC treated with IMRT were enrolled. We simulated weight loss during IMRT on the computer. Weight loss model was based on the planning computed tomography (CT) images. The original external contour of head and neck was labeled plan 0, and its volume was regarded as pretreatment normal weight. We shrank the external contour with different margins (2, 3, and 5 mm) and generated new external contours of head and neck. The volumes of reconstructed external contoursmore » were regarded as weight during radiotherapy. After recontouring outlines, the initial treatment plan was mapped to the redefined CT scans with the same beam configurations, yielding new plans. The computer model represented a theoretical proportional weight loss of 3.4% to 13.7% during the course of IMRT. The dose delivered to the planning target volume (PTV) of primary gross tumor volume and clinical target volume significantly increased by 1.9% to 2.9% and 1.8% to 2.9% because of weight loss, respectively. The dose to the PTV of gross tumor volume of lymph nodes fluctuated from −2.0% to 1.0%. The dose to the brain stem and the spinal cord was increased (p < 0.001), whereas the dose to the parotid gland was decreased (p < 0.001). Weight loss may lead to significant dosimetric change during IMRT. Repeated scanning and replanning for patients with NPC with an obvious weight loss may be necessary.« less

Delineation of clinical target volume for postoperative radiotherapy in stage IIIA-pN2 non-small-cell lung cancer

PubMed Central

Jing, Xuquan; Meng, Xue; Sun, Xindong; Yu, Jinming

2016-01-01

With the high locoregional relapse rate and the improvement of radiation technology, postoperative radiotherapy (PORT) has been widely used in the treatment of completely resected stage IIIA-pN2 non-small-cell lung cancer (NSCLC). However, there is still no definitive consensus on clinical target volume for the pN2 subgroup. This review will discuss how to delineate the clinical target volume (CTV) for pN2 subgroups of IIIA-N2 NSCLC based on the published literature and to investigate the optimal PORT CTV in this cohort of patients. Besides overall survival (OS), locoregional recurrence (LR), and radiotherapy-related toxicity of this subset of the population in the modern PORT era, selection of proper patients will also be considered in this review. In summary, it is appropriate to include involved lymph node stations and uninvolved stations at high risk in PORT CTV for patients with pN2 disease when PORT is administered. PORT can reduce LR and has the potential to improve OS. In the current era of modern radiation technology, PORT can be administered safely with well-tolerated toxicity. Clinicopathological characteristics may be helpful in selecting proper candidates for PORT. PMID:26929651

Delineation of clinical target volume for postoperative radiotherapy in stage IIIA-pN2 non-small-cell lung cancer.

PubMed

Jing, Xuquan; Meng, Xue; Sun, Xindong; Yu, Jinming

2016-01-01

With the high locoregional relapse rate and the improvement of radiation technology, postoperative radiotherapy (PORT) has been widely used in the treatment of completely resected stage IIIA-pN2 non-small-cell lung cancer (NSCLC). However, there is still no definitive consensus on clinical target volume for the pN2 subgroup. This review will discuss how to delineate the clinical target volume (CTV) for pN2 subgroups of IIIA-N2 NSCLC based on the published literature and to investigate the optimal PORT CTV in this cohort of patients. Besides overall survival (OS), locoregional recurrence (LR), and radiotherapy-related toxicity of this subset of the population in the modern PORT era, selection of proper patients will also be considered in this review. In summary, it is appropriate to include involved lymph node stations and uninvolved stations at high risk in PORT CTV for patients with pN2 disease when PORT is administered. PORT can reduce LR and has the potential to improve OS. In the current era of modern radiation technology, PORT can be administered safely with well-tolerated toxicity. Clinicopathological characteristics may be helpful in selecting proper candidates for PORT.

High volume fabrication of laser targets using MEMS techniques

NASA Astrophysics Data System (ADS)

Spindloe, C.; Arthur, G.; Hall, F.; Tomlinson, S.; Potter, R.; Kar, S.; Green, J.; Higginbotham, A.; Booth, N.; Tolley, M. K.

2016-04-01

The latest techniques for the fabrication of high power laser targets, using processes developed for the manufacture of Micro-Electro-Mechanical System (MEMS) devices are discussed. These laser targets are designed to meet the needs of the increased shot numbers that are available in the latest design of laser facilities. Traditionally laser targets have been fabricated using conventional machining or coarse etching processes and have been produced in quantities of 10s to low 100s. Such targets can be used for high complexity experiments such as Inertial Fusion Energy (IFE) studies and can have many complex components that need assembling and characterisation with high precision. Using the techniques that are common to MEMS devices and integrating these with an existing target fabrication capability we are able to manufacture and deliver targets to these systems. It also enables us to manufacture novel targets that have not been possible using other techniques. In addition, developments in the positioning systems that are required to deliver these targets to the laser focus are also required and a system to deliver the target to a focus of an F2 beam at 0.1Hz is discussed.

Delineation of Supraclavicular Target Volumes in Breast Cancer Radiation Therapy

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

Brown, Lindsay C.; Diehn, Felix E.; Boughey, Judy C.

Purpose: To map the location of gross supraclavicular metastases in patients with breast cancer, in order to determine areas at highest risk of harboring subclinical disease. Methods and Materials: Patients with axial imaging of gross supraclavicular disease were identified from an institutional breast cancer registry. Locations of the metastatic lymph nodes were transferred onto representative axial computed tomography images of the supraclavicular region and compared with the Radiation Therapy Oncology Group (RTOG) breast cancer atlas for radiation therapy planning. Results: Sixty-two patients with 161 supraclavicular nodal metastases were eligible for study inclusion. At the time of diagnosis, 117 nodal metastasesmore » were present in 44 patients. Forty-four nodal metastases in 18 patients were detected at disease recurrence, 4 of whom had received prior radiation to the supraclavicular fossa. Of the 161 nodal metastases, 95 (59%) were within the RTOG consensus volume, 4 nodal metastases (2%) in 3 patients were marginally within the volume, and 62 nodal metastases (39%) in 30 patients were outside the volume. Supraclavicular disease outside the RTOG consensus volume was located in 3 regions: at the level of the cricoid and thyroid cartilage (superior to the RTOG volume), in the posterolateral supraclavicular fossa (posterolateral to the RTOG volume), and in the lateral low supraclavicular fossa (lateral to the RTOG volume). Only women with multiple supraclavicular metastases had nodal disease that extended superiorly to the level of the thyroid cartilage. Conclusions: For women with risk of harboring subclinical supraclavicular disease warranting the addition of supraclavicular radiation, coverage of the posterior triangle and the lateral low supraclavicular region should be considered. For women with known supraclavicular disease, extension of neck coverage superior to the cricoid cartilage may be warranted.« less

Estimation of error in maximal intensity projection-based internal target volume of lung tumors: a simulation and comparison study using dynamic magnetic resonance imaging.

PubMed

Cai, Jing; Read, Paul W; Baisden, Joseph M; Larner, James M; Benedict, Stanley H; Sheng, Ke

2007-11-01

To evaluate the error in four-dimensional computed tomography (4D-CT) maximal intensity projection (MIP)-based lung tumor internal target volume determination using a simulation method based on dynamic magnetic resonance imaging (dMRI). Eight healthy volunteers and six lung tumor patients underwent a 5-min MRI scan in the sagittal plane to acquire dynamic images of lung motion. A MATLAB program was written to generate re-sorted dMRI using 4D-CT acquisition methods (RedCAM) by segmenting and rebinning the MRI scans. The maximal intensity projection images were generated from RedCAM and dMRI, and the errors in the MIP-based internal target area (ITA) from RedCAM (epsilon), compared with those from dMRI, were determined and correlated with the subjects' respiratory variability (nu). Maximal intensity projection-based ITAs from RedCAM were comparatively smaller than those from dMRI in both phantom studies (epsilon = -21.64% +/- 8.23%) and lung tumor patient studies (epsilon = -20.31% +/- 11.36%). The errors in MIP-based ITA from RedCAM correlated linearly (epsilon = -5.13nu - 6.71, r(2) = 0.76) with the subjects' respiratory variability. Because of the low temporal resolution and retrospective re-sorting, 4D-CT might not accurately depict the excursion of a moving tumor. Using a 4D-CT MIP image to define the internal target volume might therefore cause underdosing and an increased risk of subsequent treatment failure. Patient-specific respiratory variability might also be a useful predictor of the 4D-CT-induced error in MIP-based internal target volume determination.

Image-fusion of MR spectroscopic images for treatment planning of gliomas

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

Chang Jenghwa; Thakur, Sunitha; Perera, Gerard

2006-01-15

{sup 1}H magnetic resonance spectroscopic imaging (MRSI) can improve the accuracy of target delineation for gliomas, but it lacks the anatomic resolution needed for image fusion. This paper presents a simple protocol for fusing simulation computer tomography (CT) and MRSI images for glioma intensity-modulated radiotherapy (IMRT), including a retrospective study of 12 patients. Each patient first underwent whole-brain axial fluid-attenuated-inversion-recovery (FLAIR) MRI (3 mm slice thickness, no spacing), followed by three-dimensional (3D) MRSI measurements (TE/TR: 144/1000 ms) of a user-specified volume encompassing the extent of the tumor. The nominal voxel size of MRSI ranged from 8x8x10 mm{sup 3} to 12x12x10more » mm{sup 3}. A system was developed to grade the tumor using the choline-to-creatine (Cho/Cr) ratios from each MRSI voxel. The merged MRSI images were then generated by replacing the Cho/Cr value of each MRSI voxel with intensities according to the Cho/Cr grades, and resampling the poorer-resolution Cho/Cr map into the higher-resolution FLAIR image space. The FUNCTOOL processing software was also used to create the screen-dumped MRSI images in which these data were overlaid with each FLAIR MRI image. The screen-dumped MRSI images were manually translated and fused with the FLAIR MRI images. Since the merged MRSI images were intrinsically fused with the FLAIR MRI images, they were also registered with the screen-dumped MRSI images. The position of the MRSI volume on the merged MRSI images was compared with that of the screen-dumped MRSI images and was shifted until agreement was within a predetermined tolerance. Three clinical target volumes (CTVs) were then contoured on the FLAIR MRI images corresponding to the Cho/Cr grades. Finally, the FLAIR MRI images were fused with the simulation CT images using a mutual-information algorithm, yielding an IMRT plan that simultaneously delivers three different dose levels to the three CTVs. The image

Co-registration of cone beam CT and planning CT in head and neck IMRT dose estimation: a feasible adaptive radiotherapy strategy

PubMed Central

Yip, C; Thomas, C; Michaelidou, A; James, D; Lynn, R; Lei, M

2014-01-01

Objective: To investigate if cone beam CT (CBCT) can be used to estimate the delivered dose in head and neck intensity-modulated radiotherapy (IMRT). Methods: 15 patients (10 without replan and 5 with replan) were identified retrospectively. Weekly CBCT was co-registered with original planning CT. Original high-dose clinical target volume (CTV1), low-dose CTV (CTV2), brainstem, spinal cord, parotids and external body contours were copied to each CBCT and modified to account for anatomical changes. Corresponding planning target volumes (PTVs) and planning organ-at-risk volumes were created. The original plan was applied and calculated using modified per-treatment volumes on the original CT. Percentage volumetric, cumulative (planned dose delivered prior to CBCT + adaptive dose delivered after CBCT) and actual delivered (summation of weekly adaptive doses) dosimetric differences between each per-treatment and original plan were calculated. Results: There was greater volumetric change in the parotids with an average weekly difference of between −4.1% and −27.0% compared with the CTVs/PTVs (−1.8% to −5.0%). The average weekly cumulative dosimetric differences were as follows: CTV/PTV (range, −3.0% to 2.2%), ipsilateral parotid volume receiving ≥26 Gy (V26) (range, 0.5–3.2%) and contralateral V26 (range, 1.9–6.3%). In patients who required replan, the average volumetric reductions were greater: CTV1 (−2.5%), CTV2 (−6.9%), PTV1 (−4.7%), PTV2 (−11.5%), ipsilateral (−10.4%) and contralateral parotids (−12.1%), but did not result in significant dosimetric changes. Conclusion: The dosimetric changes during head and neck simultaneous integrated boost IMRT do not necessitate adaptive radiotherapy in most patients. Advances in knowledge: Our study shows that CBCT could be used for dose estimation during head and neck IMRT. PMID:24288402

Prospective Qualitative and Quantitative Analysis of Real-Time Peer Review Quality Assurance Rounds Incorporating Direct Physical Examination for Head and Neck Cancer Radiation Therapy.

PubMed

Cardenas, Carlos E; Mohamed, Abdallah S R; Tao, Randa; Wong, Andrew J R; Awan, Mussadiq J; Kuruvila, Shirly; Aristophanous, Michalis; Gunn, G Brandon; Phan, Jack; Beadle, Beth M; Frank, Steven J; Garden, Adam S; Morrison, William H; Fuller, Clifton D; Rosenthal, David I

2017-07-01

Our department has a long-established comprehensive quality assurance (QA) planning clinic for patients undergoing radiation therapy (RT) for head and neck cancer. Our aim is to assess the impact of a real-time peer review QA process on the quantitative and qualitative radiation therapy plan changes in the era of intensity modulated RT (IMRT). Prospective data for 85 patients undergoing head and neck IMRT who presented at a biweekly QA clinic after simulation and contouring were collected. A standard data collection form was used to document alterations made during this process. The original pre-QA clinical target volumes (CTVs) approved by the treating-attending physicians were saved before QA and compared with post-QA consensus CTVs. Qualitative assessment was done according to predefined criteria. Dice similarity coefficients (DSC) and other volume overlap metrics were calculated for each CTV level and were used for quantitative comparison. Changes are categorized as major, minor, and trivial according to the degree of overlap. Patterns of failure were analyzed and correlated to plan changes. All 85 patients were examined by at least 1 head and neck subspecialist radiation oncologist who was not the treating-attending physician; 80 (94%) were examined by ≥3 faculty members. New clinical findings on physical examination were found in 12 patients (14%) leading to major plan changes. Quantitative DSC analysis revealed significantly better agreement in CTV1 (0.94 ± 0.10) contours than in CTV2 (0.82 ± 0.25) and CTV3 (0.86 ± 0.2) contours (P=.0002 and P=.03, respectively; matched-pair Wilcoxon test). The experience of the treating-attending radiation oncologist significantly affected DSC values when all CTV levels were considered (P=.012; matched-pair Wilcoxon text). After a median follow-up time of 38 months, only 10 patients (12%) had local recurrence, regional recurrence, or both, mostly in central high-dose areas. Comprehensive peer review planning

Chemoradiation for ductal pancreatic carcinoma: principles of combining chemotherapy with radiation, definition of target volume and radiation dose.

PubMed

Wilkowski, Ralf; Thoma, Martin; Weingandt, Helmut; Dühmke, Eckhart; Heinemann, Volker

2005-05-10

Review of the role of chemoradiotherapy in the treatment of locally advanced pancreatic cancer with a specific focus on the technical feasibility and the integration of chemoradiotherapy into multimodal treatment concepts. Combined chemoradiotherapy of pancreatic cancer is a safe treatment with an acceptable profile of side effects when applied with modern planning and radiation techniques as well as considering tissue tolerance. Conventionally fractionated radiation regimens with total doses of 45-50 Gy and small-volume boost radiation with 5.4 Gy have found the greatest acceptance. Locoregional lymphatic drainage should be included in the planning of target volumes because the risk of tumor involvement and local or loco-regional recurrence is high. Up to now, 5-fluorouracil has been considered the "standard" agent for concurrent chemoradiotherapy. The role of gemcitabine given concurrently with radiation has not yet been defined, since high local efficacy may also be accompanied by enhanced toxicities. In addition, no dose or administration form has been determined to be "standard" up to now. The focus of presently ongoing research is to define an effective and feasible regimen of concurrent chemoradiotherapy. While preliminary results indicate promising results using gemcitabine-based chemoradiotherapy, reliable data derived from mature phase III trials are greatly needed. Intensity-modulated radiotherapy has been developed to improve target-specific radiation and to reduce organ toxicity. Its clinical relevance still needs to be defined.

Consequences of additional use of PET information for target volume delineation and radiotherapy dose distribution for esophageal cancer.

PubMed

Muijs, Christina T; Schreurs, Liesbeth M; Busz, Dianne M; Beukema, Jannet C; van der Borden, Arnout J; Pruim, Jan; Van der Jagt, Eric J; Plukker, John Th; Langendijk, Johannes A

2009-12-01

To determine the consequences of target volume (TV) modifications, based on the additional use of PET information, on radiation planning, assuming PET/CT-imaging represents the true extent of the tumour. For 21 patients with esophageal cancer, two separate TV's were retrospectively defined based on CT (CT-TV) and co-registered PET/CT images (PET/CT-TV). Two 3D-CRT plans (prescribed dose 50.4 Gy) were constructed to cover the corresponding TV's. Subsequently, these plans were compared for target coverage, normal tissue dose-volume histograms and the corresponding normal tissue complication probability (NTCP) values. The addition of PET led to the modification of CT-TV with at least 10% in 12 of 21 patients (57%) (reduction in 9, enlargement in 3). PET/CT-TV was inadequately covered by the CT-based treatment plan in 8 patients (36%). Treatment plan modifications resulted in significant changes (p<0.05) in dose distributions to heart and lungs. Corresponding changes in NTCP values ranged from -3% to +2% for radiation pneumonitis and from -0.2% to +1.2% for cardiac mortality. This study demonstrated that TV's based on CT might exclude PET-avid disease. Consequences are under dosing and thereby possibly ineffective treatment. Moreover, the addition of PET in radiation planning might result in clinical important changes in NTCP.

Estimation of Error in Maximal Intensity Projection-Based Internal Target Volume of Lung Tumors: A Simulation and Comparison Study Using Dynamic Magnetic Resonance Imaging

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

Cai Jing; Read, Paul W.; Baisden, Joseph M.

Purpose: To evaluate the error in four-dimensional computed tomography (4D-CT) maximal intensity projection (MIP)-based lung tumor internal target volume determination using a simulation method based on dynamic magnetic resonance imaging (dMRI). Methods and Materials: Eight healthy volunteers and six lung tumor patients underwent a 5-min MRI scan in the sagittal plane to acquire dynamic images of lung motion. A MATLAB program was written to generate re-sorted dMRI using 4D-CT acquisition methods (RedCAM) by segmenting and rebinning the MRI scans. The maximal intensity projection images were generated from RedCAM and dMRI, and the errors in the MIP-based internal target area (ITA)more » from RedCAM ({epsilon}), compared with those from dMRI, were determined and correlated with the subjects' respiratory variability ({nu}). Results: Maximal intensity projection-based ITAs from RedCAM were comparatively smaller than those from dMRI in both phantom studies ({epsilon} = -21.64% {+-} 8.23%) and lung tumor patient studies ({epsilon} = -20.31% {+-} 11.36%). The errors in MIP-based ITA from RedCAM correlated linearly ({epsilon} = -5.13{nu} - 6.71, r{sup 2} = 0.76) with the subjects' respiratory variability. Conclusions: Because of the low temporal resolution and retrospective re-sorting, 4D-CT might not accurately depict the excursion of a moving tumor. Using a 4D-CT MIP image to define the internal target volume might therefore cause underdosing and an increased risk of subsequent treatment failure. Patient-specific respiratory variability might also be a useful predictor of the 4D-CT-induced error in MIP-based internal target volume determination.« less

Sci—Fri AM: Mountain — 06: Optimizing planning target volume in lung radiotherapy using deformable registration

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

Hoang, P; Wierzbicki, M; Juravinski Cancer Centre, Medical Physics Department, Hamilton, Ontario

A four dimensional computed tomography (4DCT) image is acquired for all radically treated, lung cancer patients to define the internal target volume (ITV), which encompasses tumour motion due to breathing and subclinical disease. Patient set-up error and anatomical motion that is not due to breathing is addressed through an additional 1 cm margin around the ITV to obtain the planning target volume (PTV). The objective of this retrospective study is to find the minimum PTV margin that provides an acceptable probability of delivering the prescribed dose to the ITV. Acquisition of a kV cone beam computed tomography (CBCT) image atmore » each fraction was used to shift the treatment couch to accurately align the spinal cord and carina. Our method utilized deformable image registration to automatically position the planning ITV on each CBCT. We evaluated the percentage of the ITV surface that fell within various PTVs for 79 fractions across 18 patients. Treatment success was defined as a situation where at least 99% of the ITV is covered by the PTV. Overall, this is to be achieved in at least 90% of the treatment fractions. The current approach with a 1cm PTV margin was successful ∼96% of the time. This analysis revealed that the current margin can be reduced to 0.8cm isotropic or 0.6×0.6×1 cm{sup 3} non-isotropic, which were successful 92 and 91 percent of the time respectively. Moreover, we have shown that these margins maintain accuracy, despite intrafractional variation, and maximize CBCT image guidance capabilities.« less

TU-E-BRA-11: Volume of Interest Cone Beam CT with a Low-Z Linear Accelerator Target: Proof-of-Concept.

PubMed

Robar, J; Parsons, D; Berman, A; MacDonald, A

2012-06-01

This study demonstrates feasibility and advantages of volume of interest (VOI) cone beam CT (CBCT) imaging performed with an x-ray beam generated from 2.35 MeV electrons incident on a carbon linear accelerator target. The electron beam energy was reduced to 2.35 MeV in a Varian 21EX linear accelerator containing a 7.6 mm thick carbon x-ray target. Arbitrary imaging volumes were defined in the planning system to produce dynamic MLC sequences capable of tracking off-axis VOIs in phantoms. To reduce truncation artefacts, missing data in projection images were completed using a priori DRR information from the planning CT set. The feasibility of the approach was shown through imaging of an anthropomorphic phantom and the head-and-neck section of a lamb. TLD800 and EBT2 radiochromic film measurements were used to compare the VOI dose distributions with those for full-field techniques. CNR was measured for VOIs ranging from 4 to 15 cm diameter. The 2.35 MV/Carbon beam provides favorable CNR characteristics, although marked boundary and cupping artefacts arise due to truncation of projection data. These artefacts are largely eliminated using the DRR filling technique. Imaging dose was reduced by 5-10% and 75% inside and outside of the VOI, respectively, compared to full-field imaging for a cranial VOI. For the 2.35 MV/Carbon beam, CNR was shown to be approximately invariant with VOI dimension for bone and lung objects. This indicates that the advantage of the VOI approach with the low-Z target beam is substantial imaging dose reduction, not improvement of image quality. VOI CBCT using a 2.35 MV/Carbon beam is a feasible technique whereby a chosen imaging volume can be defined in the planning system and tracked during acquisition. The novel x-ray beam affords good CNR characteristics while imaging dose is localized to the chosen VOI. Funding for this project has been received from Varian Medical, Incorporated. © 2012 American Association of Physicists in Medicine.

Evaluation of dose coverage to target volume and normal tissue sparing in the adjuvant radiotherapy of gastric cancers: 3D-CRT compared with dynamic IMRT.

PubMed

Murthy, Kk; Shukeili, Ka; Kumar, Ss; Davis, Ca; Chandran, Rr; Namrata, S

2010-01-01

To assess the potential advantage of intensity-modulated radiotherapy (IMRT) over 3D-conformal radiotherapy (3D-CRT) planning in postoperative adjuvant radiotherapy for patients with gastric carcinoma. In a retrospective study, for plan comparison, dose distribution was recalculated in 15 patients treated with 3D-CRT on the contoured structures of same CT images using an IMRT technique. 3D-conformal plans with three fields and four-fields were compared with seven-field dynamic IMRT plans. The different plans were compared by analyzing the dose coverage of planning target volume using TV(95), D(mean), uniformity index, conformity index and homogeneity index parameters. To assess critical organ sparing, D(mean), D(max), dose to one-third and two-third volumes of the OARs and percentage of volumes receiving more than their tolerance doses were compared. The average dose coverage values of PTV with 3F-CRT and 4F-CRT plans were comparable, where as IMRT plans achieved better target coverage(p<0.001) with higher conformity index value of 0.81±0.07 compared to both the 3D-CRT plans. The doses to the liver and bowel reduced significantly (p<0.001) with IMRT plans compared to other 3D-CRT plans. For all OARs the percentage of volumes receiving more than their tolerance doses were reduced with the IMRT plans. This study showed that a better target coverage and significant dose reduction to OARs could be achieved with the IMRT plans. The IMRT can be preferred with caution for organ motion. The authors are currently studying organ motion in the upper abdomen to use IMRT for patient treatment.

Comparing masked target transform volume (MTTV) clutter metric to human observer evaluation of visual clutter

NASA Astrophysics Data System (ADS)

Camp, H. A.; Moyer, Steven; Moore, Richard K.

2010-04-01

The Night Vision and Electronic Sensors Directorate's current time-limited search (TLS) model, which makes use of the targeting task performance (TTP) metric to describe image quality, does not explicitly account for the effects of visual clutter on observer performance. The TLS model is currently based on empirical fits to describe human performance for a time of day, spectrum and environment. Incorporating a clutter metric into the TLS model may reduce the number of these empirical fits needed. The masked target transform volume (MTTV) clutter metric has been previously presented and compared to other clutter metrics. Using real infrared imagery of rural images with varying levels of clutter, NVESD is currently evaluating the appropriateness of the MTTV metric. NVESD had twenty subject matter experts (SME) rank the amount of clutter in each scene in a series of pair-wise comparisons. MTTV metric values were calculated and then compared to the SME observers rankings. The MTTV metric ranked the clutter in a similar manner to the SME evaluation, suggesting that the MTTV metric may emulate SME response. This paper is a first step in quantifying clutter and measuring the agreement to subjective human evaluation.

Impact of 4D-(18)FDG-PET/CT imaging on target volume delineation in SBRT patients with central versus peripheral lung tumors. Multi-reader comparative study.

PubMed

Chirindel, Alin; Adebahr, Sonja; Schuster, Daniel; Schimek-Jasch, Tanja; Schanne, Daniel H; Nemer, Ursula; Mix, Michael; Meyer, Philipp; Grosu, Anca-Ligia; Brunner, Thomas; Nestle, Ursula

2015-06-01

Evaluation of the effect of co-registered 4D-(18)FDG-PET/CT for SBRT target delineation in patients with central versus peripheral lung tumors. Analysis of internal target volume (ITV) delineation of central and peripheral lung lesions in 21 SBRT-patients. Manual delineation was performed by 4 observers in 2 contouring phases: on respiratory gated 4DCT with diagnostic 3DPET available aside (CT-ITV) and on co-registered 4DPET/CT (PET/CT-ITV). Comparative analysis of volumes and inter-reader agreement. 11 cases of peripheral and 10 central lesions were evaluated. In peripheral lesions, average CT-ITV was 6.2 cm(3) and PET/CT-ITV 8.6 cm(3), resembling a mean change in hypothetical radius of 2 mm. For both CT-ITVs and PET/CT-ITVs inter reader agreement was good and unchanged (0.733 and 0.716; p=0.58). All PET/CT-ITVs stayed within the PTVs derived from CT-ITVs. In central lesions, average CT-ITVs were 42.1 cm(3), PET/CT-ITVs 44.2 cm(3), without significant overall volume changes. Inter-reader agreement improved significantly (0.665 and 0.750; p<0.05). 2/10 PET/CT-ITVs exceeded the PTVs derived from CT-ITVs by >1 ml in average for all observers. The addition of co-registered 4DPET data to 4DCT based target volume delineation for SBRT of centrally located lung tumors increases the inter-observer agreement and may help to avoid geographic misses. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Bolus-dependent dosimetric effect of positioning errors for tangential scalp radiotherapy with helical tomotherapy

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

Lobb, Eric, E-mail: eclobb2@gmail.com

2014-04-01

The dosimetric effect of errors in patient position is studied on-phantom as a function of simulated bolus thickness to assess the need for bolus utilization in scalp radiotherapy with tomotherapy. A treatment plan is generated on a cylindrical phantom, mimicking a radiotherapy technique for the scalp utilizing primarily tangential beamlets. A planning target volume with embedded scalplike clinical target volumes (CTVs) is planned to a uniform dose of 200 cGy. Translational errors in phantom position are introduced in 1-mm increments and dose is recomputed from the original sinogram. For each error the maximum dose, minimum dose, clinical target dose homogeneitymore » index (HI), and dose-volume histogram (DVH) are presented for simulated bolus thicknesses from 0 to 10 mm. Baseline HI values for all bolus thicknesses were in the 5.5 to 7.0 range, increasing to a maximum of 18.0 to 30.5 for the largest positioning errors when 0 to 2 mm of bolus is used. Utilizing 5 mm of bolus resulted in a maximum HI value of 9.5 for the largest positioning errors. Using 0 to 2 mm of bolus resulted in minimum and maximum dose values of 85% to 94% and 118% to 125% of the prescription dose, respectively. When using 5 mm of bolus these values were 98.5% and 109.5%. DVHs showed minimal changes in CTV dose coverage when using 5 mm of bolus, even for the largest positioning errors. CTV dose homogeneity becomes increasingly sensitive to errors in patient position as bolus thickness decreases when treating the scalp with primarily tangential beamlets. Performing a radial expansion of the scalp CTV into 5 mm of bolus material minimizes dosimetric sensitivity to errors in patient position as large as 5 mm and is therefore recommended.« less

Utilization of PET-CT in target volume delineation for three-dimensional conformal radiotherapy in patients with non-small cell lung cancer and atelectasis.

PubMed

Yin, Li-Jie; Yu, Xiao-Bin; Ren, Yan-Gang; Gu, Guang-Hai; Ding, Tian-Gui; Lu, Zhi

2013-03-18

To investigate the utilization of PET-CT in target volume delineation for three-dimensional conformal radiotherapy in patients with non-small cell lung cancer (NSCLC) and atelectasis. Thirty NSCLC patients who underwent radical radiotherapy from August 2010 to March 2012 were included in this study. All patients were pathologically confirmed to have atelectasis by imaging examination. PET-CT scanning was performed in these patients. According to the PET-CT scan results, the gross tumor volume (GTV) and organs at risk (OARs, including the lungs, heart, esophagus and spinal cord) were delineated separately both on CT and PET-CT images. The clinical target volume (CTV) was defined as the GTV plus a margin of 6-8 mm, and the planning target volume (PTV) as the GTV plus a margin of 10-15mm. An experienced physician was responsible for designing treatment plans PlanCT and PlanPET-CT on CT image sets. 95% of the PTV was encompassed by the 90% isodose curve, and the two treatment plans kept the same beam direction, beam number, gantry angle, and position of the multi-leaf collimator as much as possible. The GTV was compared using a target delineation system, and doses distributions to OARs were compared on the basis of dose-volume histogram (DVH) parameters. The GTVCT and GTVPET-CT had varying degrees of change in all 30 patients, and the changes in the GTVCT and GTVPET-CT exceeded 25% in 12 (40%) patients. The GTVPET-CT decreased in varying degrees compared to the GTVCT in 22 patients. Their median GTVPET-CT and median GTVPET-CT were 111.4 cm3 (range, 37.8 cm3-188.7 cm3) and 155.1 cm3 (range, 76.2 cm3-301.0 cm3), respectively, and the former was 43.7 cm3 (28.2%) less than the latter. The GTVPET-CT increased in varying degrees compared to the GTVCT in 8 patients. Their median GTVPET-CT and median GTVPET-CT were 144.7 cm3 (range, 125.4 cm3-178.7 cm3) and 125.8 cm3 (range, 105.6 cm3-153.5 cm3), respectively, and the former was 18.9 cm3 (15.0%) greater than the latter

Single-Isocenter Multiple-Target Stereotactic Radiosurgery: Risk of Compromised Coverage

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

Roper, Justin, E-mail: justin.roper@emory.edu; Department of Biostatistics and Bioinformatics, Winship Cancer Institute of Emory University, Atlanta, Georgia; Chanyavanich, Vorakarn

2015-11-01

Purpose: To determine the dosimetric effects of rotational errors on target coverage using volumetric modulated arc therapy (VMAT) for multitarget stereotactic radiosurgery (SRS). Methods and Materials: This retrospective study included 50 SRS cases, each with 2 intracranial planning target volumes (PTVs). Both PTVs were planned for simultaneous treatment to 21 Gy using a single-isocenter, noncoplanar VMAT SRS technique. Rotational errors of 0.5°, 1.0°, and 2.0° were simulated about all axes. The dose to 95% of the PTV (D95) and the volume covered by 95% of the prescribed dose (V95) were evaluated using multivariate analysis to determine how PTV coverage was relatedmore » to PTV volume, PTV separation, and rotational error. Results: At 0.5° rotational error, D95 values and V95 coverage rates were ≥95% in all cases. For rotational errors of 1.0°, 7% of targets had D95 and V95 values <95%. Coverage worsened substantially when the rotational error increased to 2.0°: D95 and V95 values were >95% for only 63% of the targets. Multivariate analysis showed that PTV volume and distance to isocenter were strong predictors of target coverage. Conclusions: The effects of rotational errors on target coverage were studied across a broad range of SRS cases. In general, the risk of compromised coverage increased with decreasing target volume, increasing rotational error and increasing distance between targets. Multivariate regression models from this study may be used to quantify the dosimetric effects of rotational errors on target coverage given patient-specific input parameters of PTV volume and distance to isocenter.« less

System and method for radiation dose calculation within sub-volumes of a monte carlo based particle transport grid

DOEpatents

Bergstrom, Paul M.; Daly, Thomas P.; Moses, Edward I.; Patterson, Jr., Ralph W.; Schach von Wittenau, Alexis E.; Garrett, Dewey N.; House, Ronald K.; Hartmann-Siantar, Christine L.; Cox, Lawrence J.; Fujino, Donald H.

2000-01-01

A system and method is disclosed for radiation dose calculation within sub-volumes of a particle transport grid. In a first step of the method voxel volumes enclosing a first portion of the target mass are received. A second step in the method defines dosel volumes which enclose a second portion of the target mass and overlap the first portion. A third step in the method calculates common volumes between the dosel volumes and the voxel volumes. A fourth step in the method identifies locations in the target mass of energy deposits. And, a fifth step in the method calculates radiation doses received by the target mass within the dosel volumes. A common volume calculation module inputs voxel volumes enclosing a first portion of the target mass, inputs voxel mass densities corresponding to a density of the target mass within each of the voxel volumes, defines dosel volumes which enclose a second portion of the target mass and overlap the first portion, and calculates common volumes between the dosel volumes and the voxel volumes. A dosel mass module, multiplies the common volumes by corresponding voxel mass densities to obtain incremental dosel masses, and adds the incremental dosel masses corresponding to the dosel volumes to obtain dosel masses. A radiation transport module identifies locations in the target mass of energy deposits. And, a dose calculation module, coupled to the common volume calculation module and the radiation transport module, for calculating radiation doses received by the target mass within the dosel volumes.

Consensus Contouring Guidelines for Postoperative Stereotactic Body Radiation Therapy for Metastatic Solid Tumor Malignancies to the Spine

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

Redmond, Kristin J., E-mail: kjanson3@jhmi.edu; Robertson, Scott; Lo, Simon S.

Purpose: To develop consensus contouring guidelines for postoperative stereotactic body radiation therapy (SBRT) for spinal metastases. Methods and Materials: Ten spine SBRT specialists representing 10 international centers independently contoured the clinical target volume (CTV), planning target volume (PTV), spinal cord, and spinal cord planning organ at risk volume (PRV) for 10 representative clinical scenarios in postoperative spine SBRT for metastatic solid tumor malignancies. Contours were imported into the Computational Environment for Radiotherapy Research. Agreement between physicians was calculated with an expectation minimization algorithm using simultaneous truth and performance level estimation with κ statistics. Target volume definition guidelines were established by finding optimizedmore » confidence level consensus contours using histogram agreement analyses. Results: Nine expert radiation oncologists and 1 neurosurgeon completed contours for all 10 cases. The mean sensitivity and specificity were 0.79 (range, 0.71-0.89) and 0.94 (range, 0.90-0.99) for the CTV and 0.79 (range, 0.70-0.95) and 0.92 (range, 0.87-0.99) for the PTV), respectively. Mean κ agreement, which demonstrates the probability that contours agree by chance alone, was 0.58 (range, 0.43-0.70) for CTV and 0.58 (range, 0.37-0.76) for PTV (P<.001 for all cases). Optimized consensus contours were established for all patients with 80% confidence interval. Recommendations for CTV include treatment of the entire preoperative extent of bony and epidural disease, plus immediately adjacent bony anatomic compartments at risk of microscopic disease extension. In particular, a “donut-shaped” CTV was consistently applied in cases of preoperative circumferential epidural extension, regardless of extent of residual epidural extension. Otherwise more conformal anatomic-based CTVs were determined and described. Spinal instrumentation was consistently excluded from the CTV. Conclusions: We

Variation in the Gross Tumor Volume and Clinical Target Volume for Preoperative Radiotherapy of Primary Large High-Grade Soft Tissue Sarcoma of the Extremity Among RTOG Sarcoma Radiation Oncologists

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

Wang Dian, E-mail: dwang@mcw.edu; Bosch, Walter; Kirsch, David G.

Purpose: To evaluate variability in the definition of preoperative radiotherapy gross tumor volume (GTV) and clinical target volume (CTV) delineated by sarcoma radiation oncologists. Methods and Materials: Extremity sarcoma planning CT images along with the corresponding diagnostic MRI from two patients were distributed to 10 Radiation Therapy Oncology Group sarcoma radiation oncologists with instructions to define GTV and CTV using standardized guidelines. The CT data with contours were then returned for central analysis. Contours representing statistically corrected 95% (V95) and 100% (V100) agreement were computed for each structure. Results: For the GTV, the minimum, maximum, mean (SD) volumes (mL) weremore » 674, 798, 752 {+-} 35 for the lower extremity case and 383, 543, 447 {+-} 46 for the upper extremity case. The volume (cc) of the union, V95 and V100 were 882, 761, and 752 for the lower, and 587, 461, and 455 for the upper extremity, respectively. The overall GTV agreement was judged to be almost perfect in both lower and upper extremity cases (kappa = 0.9 [p < 0.0001] and kappa = 0.86 [p < 0.0001]). For the CTV, the minimum, maximum, mean (SD) volumes (mL) were 1145, 1911, 1605 {+-} 211 for the lower extremity case and 637, 1246, 1006 {+-} 180 for the upper extremity case. The volume (cc) of the union, V95, and V100 were 2094, 1609, and 1593 for the lower, and 1533, 1020, and 965 for the upper extremity cases, respectively. The overall CTV agreement was judged to be almost perfect in the lower extremity case (kappa = 0.85 [p < 0.0001]) but only substantial in the upper extremity case (kappa = 0.77 [p < 0.0001]). Conclusions: Almost perfect agreement existed in the GTV of these two representative cases. Tshere was no significant disagreement in the CTV of the lower extremity, but variation in the CTV of upper extremity was seen, perhaps related to the positional differences between the planning CT and the diagnostic MRI.« less

Dosimetric accuracy of a treatment planning system for actively scanned proton beams and small target volumes: Monte Carlo and experimental validation

NASA Astrophysics Data System (ADS)

Magro, G.; Molinelli, S.; Mairani, A.; Mirandola, A.; Panizza, D.; Russo, S.; Ferrari, A.; Valvo, F.; Fossati, P.; Ciocca, M.

2015-09-01

This study was performed to evaluate the accuracy of a commercial treatment planning system (TPS), in optimising proton pencil beam dose distributions for small targets of different sizes (5-30 mm side) located at increasing depths in water. The TPS analytical algorithm was benchmarked against experimental data and the FLUKA Monte Carlo (MC) code, previously validated for the selected beam-line. We tested the Siemens syngo® TPS plan optimisation module for water cubes fixing the configurable parameters at clinical standards, with homogeneous target coverage to a 2 Gy (RBE) dose prescription as unique goal. Plans were delivered and the dose at each volume centre was measured in water with a calibrated PTW Advanced Markus® chamber. An EBT3® film was also positioned at the phantom entrance window for the acquisition of 2D dose maps. Discrepancies between TPS calculated and MC simulated values were mainly due to the different lateral spread modeling and resulted in being related to the field-to-spot size ratio. The accuracy of the TPS was proved to be clinically acceptable in all cases but very small and shallow volumes. In this contest, the use of MC to validate TPS results proved to be a reliable procedure for pre-treatment plan verification.

Dosimetric accuracy of a treatment planning system for actively scanned proton beams and small target volumes: Monte Carlo and experimental validation.

PubMed

Magro, G; Molinelli, S; Mairani, A; Mirandola, A; Panizza, D; Russo, S; Ferrari, A; Valvo, F; Fossati, P; Ciocca, M

2015-09-07

This study was performed to evaluate the accuracy of a commercial treatment planning system (TPS), in optimising proton pencil beam dose distributions for small targets of different sizes (5-30 mm side) located at increasing depths in water. The TPS analytical algorithm was benchmarked against experimental data and the FLUKA Monte Carlo (MC) code, previously validated for the selected beam-line. We tested the Siemens syngo(®) TPS plan optimisation module for water cubes fixing the configurable parameters at clinical standards, with homogeneous target coverage to a 2 Gy (RBE) dose prescription as unique goal. Plans were delivered and the dose at each volume centre was measured in water with a calibrated PTW Advanced Markus(®) chamber. An EBT3(®) film was also positioned at the phantom entrance window for the acquisition of 2D dose maps. Discrepancies between TPS calculated and MC simulated values were mainly due to the different lateral spread modeling and resulted in being related to the field-to-spot size ratio. The accuracy of the TPS was proved to be clinically acceptable in all cases but very small and shallow volumes. In this contest, the use of MC to validate TPS results proved to be a reliable procedure for pre-treatment plan verification.

Projection-data based temporal maximum attenuation computed tomography: determination of internal target volume for lung cancer against intra-fraction motion

NASA Astrophysics Data System (ADS)

Mori, Shinichiro; Kanematsu, Nobuyuki; Asakura, Hiroshi; Endo, Masahiro

2007-02-01

The concept of internal target volume (ITV) is highly significant in radiotherapy for the lung, an organ which is hampered by organ motion. To date, different methods to obtain the ITV have been published and are therefore available. To define ITV, we developed a new method by adapting a time filter to the four-dimensional CT scan technique (4DCT) which is projection-data processing (4D projection data maximum attenuation (4DPM)), and compared it with reconstructed image processing (4D image maximum intensity projection (4DIM)) using a phantom and clinical evaluations. 4DIM and 4DPM captured accurate maximum intensity volume (MIV), that is tumour encompassing volume, easily. Although 4DIM increased the CT number 1.8 times higher than 4DPM, 4DPM provided the original tumour CT number for MIV via a reconstruction algorithm. In the patient with lung fibrosis honeycomb, the MIV with 4DIM is 0.7 cm larger than that for cine imaging in the cranio-caudal direction. 4DPM therefore provided an accurate MIV independent of patient characteristics and reconstruction conditions. These findings indicate the usefulness of 4DPM in determining ITV in radiotherapy.

Are there benefits or harm from pressure targeting during lung-protective ventilation?

PubMed

MacIntyre, Neil R; Sessler, Curtis N

2010-02-01

Mechanically, breath design is usually either flow/volume-targeted or pressure-targeted. Both approaches can effectively provide lung-protective ventilation, but they prioritize different ventilation parameters, so their responses to changing respiratory-system mechanics and patient effort are different. These different response behaviors have advantages and disadvantages that can be important in specific circumstances. Flow/volume targeting guarantees a set minute ventilation but sometimes may be difficult to synchronize with patient effort, and it will not limit inspiratory pressure. In contrast, pressure targeting, with its variable flow, may be easier to synchronize and will limit inspiratory pressure, but it provides no control over delivered volume. Skilled clinicians can maximize benefits and minimize problems with either flow/volume targeting or pressure targeting. Indeed, as is often the case in managing complex life-support devices, it is operator expertise rather than the device design features that most impacts patient outcomes.

Reproducibility of lung tumor position and reduction of lung mass within the planning target volume using active breathing control (ABC).

PubMed

Cheung, Patrick C F; Sixel, Katharina E; Tirona, Romeo; Ung, Yee C

2003-12-01

The active breathing control (ABC) device allows for temporary immobilization of respiratory motion by implementing a breath hold at a predefined relative lung volume and air flow direction. The purpose of this study was to quantitatively evaluate the ability of the ABC device to immobilize peripheral lung tumors at a reproducible position, increase total lung volume, and thereby reduce lung mass within the planning target volume (PTV). Ten patients with peripheral non-small-cell lung cancer tumors undergoing radiotherapy had CT scans of their thorax with and without ABC inspiration breath hold during the first 5 days of treatment. Total lung volumes were determined from the CT data sets. Each peripheral lung tumor was contoured by one physician on all CT scans to generate gross tumor volumes (GTVs). The lung density and mass contained within a 1.5-cm PTV margin around each peripheral tumor was calculated using CT numbers. Using the center of the GTV from the Day 1 ABC scan as the reference, the displacement of subsequent GTV centers on Days 2 to 5 for each patient with ABC applied was calculated in three dimensions. With the use of ABC inspiration breath hold, total lung volumes increased by an average of 42%. This resulted in an average decrease in lung mass of 18% within a standard 1.5-cm PTV margin around the GTV. The average (+/- standard deviation) displacement of GTV centers with ABC breath hold applied was 0.3 mm (+/- 1.8 mm), 1.2 mm (+/- 2.3 mm), and 1.1 mm (+/- 3.5 mm) in the lateral direction, anterior-posterior direction, and superior-inferior direction, respectively. Results from this study indicate that there remains some inter-breath hold variability in peripheral lung tumor position with the use of ABC inspiration breath hold, which prevents significant PTV margin reduction. However, lung volumes can significantly increase, thereby decreasing the mass of lung within a standard PTV.

The dosimetric impact of daily setup error on target volumes and surrounding normal tissue in the treatment of prostate cancer with intensity-modulated radiation therapy

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

Algan, Ozer, E-mail: oalgan@ouhsc.edu; Jamgade, Ambarish; Ali, Imad

2012-01-01

The purpose of this study was to evaluate the impact of daily setup error and interfraction organ motion on the overall dosimetric radiation treatment plans. Twelve patients undergoing definitive intensity-modulated radiation therapy (IMRT) treatments for prostate cancer were evaluated in this institutional review board-approved study. Each patient had fiducial markers placed into the prostate gland before treatment planning computed tomography scan. IMRT plans were generated using the Eclipse treatment planning system. Each patient was treated to a dose of 8100 cGy given in 45 fractions. In this study, we retrospectively created a plan for each treatment day that had amore » shift available. To calculate the dose, the patient would have received under this plan, we mathematically 'negated' the shift by moving the isocenter in the exact opposite direction of the shift. The individualized daily plans were combined to generate an overall plan sum. The dose distributions from these plans were compared with the treatment plans that were used to treat the patients. Three-hundred ninety daily shifts were negated and their corresponding plans evaluated. The mean isocenter shift based on the location of the fiducial markers was 3.3 {+-} 6.5 mm to the right, 1.6 {+-} 5.1 mm posteriorly, and 1.0 {+-} 5.0 mm along the caudal direction. The mean D95 doses for the prostate gland when setup error was corrected and uncorrected were 8228 and 7844 cGy (p < 0.002), respectively, and for the planning target volume (PTV8100) was 8089 and 7303 cGy (p < 0.001), respectively. The mean V95 values when patient setup was corrected and uncorrected were 99.9% and 87.3%, respectively, for the PTV8100 volume (p < 0.0001). At an individual patient level, the difference in the D95 value for the prostate volume could be >1200 cGy and for the PTV8100 could approach almost 2000 cGy when comparing corrected against uncorrected plans. There was no statistically significant difference in the D35

Multimodal Hierarchical Imaging of Serial Sections for Finding Specific Cellular Targets within Large Volumes

PubMed Central

Wacker, Irene U.; Veith, Lisa; Spomer, Waldemar; Hofmann, Andreas; Thaler, Marlene; Hillmer, Stefan; Gengenbach, Ulrich; Schröder, Rasmus R.

2018-01-01

Targeting specific cells at ultrastructural resolution within a mixed cell population or a tissue can be achieved by hierarchical imaging using a combination of light and electron microscopy. Samples embedded in resin are sectioned into arrays consisting of ribbons of hundreds of ultrathin sections and deposited on pieces of silicon wafer or conductively coated coverslips. Arrays are imaged at low resolution using a digital consumer like smartphone camera or light microscope (LM) for a rapid large area overview, or a wide field fluorescence microscope (fluorescence light microscopy (FLM)) after labeling with fluorophores. After post-staining with heavy metals, arrays are imaged in a scanning electron microscope (SEM). Selection of targets is possible from 3D reconstructions generated by FLM or from 3D reconstructions made from the SEM image stacks at intermediate resolution if no fluorescent markers are available. For ultrastructural analysis, selected targets are finally recorded in the SEM at high-resolution (a few nanometer image pixels). A ribbon-handling tool that can be retrofitted to any ultramicrotome is demonstrated. It helps with array production and substrate removal from the sectioning knife boat. A software platform that allows automated imaging of arrays in the SEM is discussed. Compared to other methods generating large volume EM data, such as serial block-face SEM (SBF-SEM) or focused ion beam SEM (FIB-SEM), this approach has two major advantages: (1) The resin-embedded sample is conserved, albeit in a sliced-up version. It can be stained in different ways and imaged with different resolutions. (2) As the sections can be post-stained, it is not necessary to use samples strongly block-stained with heavy metals to introduce contrast for SEM imaging or render the tissue blocks conductive. This makes the method applicable to a wide variety of materials and biological questions. Particularly prefixed materials e.g., from biopsy banks and pathology labs

A method to combine target volume data from 3D and 4D planned thoracic radiotherapy patient cohorts for machine learning applications.

PubMed

Johnson, Corinne; Price, Gareth; Khalifa, Jonathan; Faivre-Finn, Corinne; Dekker, Andre; Moore, Christopher; van Herk, Marcel

2018-02-01

The gross tumour volume (GTV) is predictive of clinical outcome and consequently features in many machine-learned models. 4D-planning, however, has prompted substitution of the GTV with the internal gross target volume (iGTV). We present and validate a method to synthesise GTV data from the iGTV, allowing the combination of 3D and 4D planned patient cohorts for modelling. Expert delineations in 40 non-small cell lung cancer patients were used to develop linear fit and erosion methods to synthesise the GTV volume and shape. Quality was assessed using Dice Similarity Coefficients (DSC) and closest point measurements; by calculating dosimetric features; and by assessing the quality of random forest models built on patient populations with and without synthetic GTVs. Volume estimates were within the magnitudes of inter-observer delineation variability. Shape comparisons produced mean DSCs of 0.8817 and 0.8584 for upper and lower lobe cases, respectively. A model trained on combined true and synthetic data performed significantly better than models trained on GTV alone, or combined GTV and iGTV data. Accurate synthesis of GTV size from the iGTV permits the combination of lung cancer patient cohorts, facilitating machine learning applications in thoracic radiotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Target volume definition for 18F-FDG PET-positive lymph nodes in radiotherapy of patients with non-small cell lung cancer.

PubMed

Nestle, Ursula; Schaefer-Schuler, Andrea; Kremp, Stephanie; Groeschel, Andreas; Hellwig, Dirk; Rübe, Christian; Kirsch, Carl-Martin

2007-04-01

FDG PET is increasingly used in radiotherapy planning. Recently, we demonstrated substantial differences in target volumes when applying different methods of FDG-based contouring in primary lung tumours (Nestle et al., J Nucl Med 2005;46:1342-8). This paper focusses on FDG-positive mediastinal lymph nodes (LN(PET)). In our institution, 51 NSCLC patients who were candidates for radiotherapy prospectively underwent staging FDG PET followed by a thoracic PET scan in the treatment position and a planning CT. Eleven of them had 32 distinguishable non-confluent mediastinal or hilar nodal FDG accumulations (LN(PET)). For these, sets of gross tumour volumes (GTVs) were generated at both acquisition times by four different PET-based contouring methods (visual: GTV(vis); 40% SUVmax: GTV40; SUV=2.5: GTV2.5; target/background (T/B) algorithm: GTV(bg)). All differences concerning GTV sizes were within the range of the resolution of the PET system. The detectability and technical delineability of the GTVs were significantly better in the late scans (e.g. p = 0.02 for diagnostic application of SUVmax = 2.5; p = 0.0001 for technical delineability by GTV2.5; p = 0.003 by GTV40), favouring the GTV(bg) method owing to satisfactory overall applicability and independence of GTVs from acquisition time. Compared with CT, the majority of PET-based GTVs were larger, probably owing to resolution effects, with a possible influence of lesion movements. For nodal GTVs, different methods of contouring did not lead to clinically relevant differences in volumes. However, there were significant differences in technical delineability, especially after early acquisition. Overall, our data favour a late acquisition of FDG PET scans for radiotherapy planning, and the use of a T/B algorithm for GTV contouring.

SU-F-T-205: Effectiveness of Robust Treatment Planning to Account for Inter- Fractional Variation in Intensity Modulated Proton Therapy for Head Neck Cancer

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

Li, X; Zhang, J; Qin, A

2016-06-15

Purpose: To evaluate the potential benefits of robust optimization in intensity modulated proton therapy(IMPT) treatment planning to account for inter-fractional variation for Head Neck Cancer(HNC). Methods: One patient with bilateral HNC previous treated at our institution was used in this study. Ten daily CBCTs were selected. The CT numbers of the CBCTs were corrected by mapping the CT numbers from simulation CT via Deformable Image Registration. The planning target volumes(PTVs) were defined by a 3mm expansion from clinical target volumes(CTVs). The prescription was 70Gy, 54Gy to CTV1, CTV2, and PTV1, PTV2 for robust optimized(RO) and conventionally optimized(CO) plans respectively. Bothmore » techniques were generated by RayStation with the same beam angles: two anterior oblique and two posterior oblique angles. The similar dose constraints were used to achieve 99% of CTV1 received 100% prescription dose while kept the hotspots less than 110% of the prescription. In order to evaluate the dosimetric result through the course of treatment, the contours were deformed from simulation CT to daily CBCTs, modified, and approved by a radiation oncologist. The initial plan on the simulation CT was re-replayed on the daily CBCTs followed the bony alignment. The target coverage was evaluated using the daily doses and the cumulative dose. Results: Eight of 10 daily deliveries with using RO plan achieved at least 95% prescription dose to CTV1 and CTV2, while still kept maximum hotspot less than 112% of prescription compared with only one of 10 for the CO plan to achieve the same standards. For the cumulative doses, the target coverage for both RO and CO plans was quite similar, which was due to the compensation of cold and hot spots. Conclusion: Robust optimization can be effectively applied to compensate for target dose deficit caused by inter-fractional target geometric variation in IMPT treatment planning.« less

Functional Requirements of a Target Description System for Vulnerability Analysis

DTIC Science & Technology

1979-11-01

called GIFT .1,2 Together the COMGEOM description model and GIFT codes make up the BRL’s target description system. The significance of a target...and modifying target descriptions are described. 1 Lawrence W. Bain, Jr. and Mathew J. Reisinger, "The GIFT Code User Manual; Volume 1...34The GIFT Code User Manual; Volume II, The Output Options," unpublished draft of BRL report. II. UNDERLYING PHILOSOPHY The BRL has a computer

Determination of internal target volume for radiation treatment planning of esophageal cancer by using 4-dimensional computed tomography (4DCT).

PubMed

Chen, Xiaojian; Lu, Haijun; Tai, An; Johnstone, Candice; Gore, Elizabeth; Li, X Allen

2014-09-01

To determine an efficient strategy for the generation of the internal target volume (ITV) for radiation treatment planning for esophageal cancer using 4-dimensional computed tomography (4DCT). 4DCT sets acquired for 20 patients with esophageal carcinoma were analyzed. Each of the 4DCT sets was binned into 10 respiratory phases. For each patient, the gross tumor volume (GTV) was delineated on the 4DCT set at each phase. Various strategies to derive ITV were explored, including the volume from the maximum intensity projection (MIP; ITV_MIP), unions of the GTVs from selected multiple phases ITV2 (0% and 50% phases), ITV3 (ITV2 plus 80%), and ITV4 (ITV3 plus 60%), as well as the volumes expanded from ITV2 and ITV3 with a uniform margin. These ITVs were compared to ITV10 (the union of the GTVs for all 10 phases) and the differences were measured with the overlap ratio (OR) and relative volume ratio (RVR) relative to ITV10 (ITVx/ITV10). For all patients studied, the average GTV from a single phase was 84.9% of ITV10. The average ORs were 91.2%, 91.3%, 94.5%, and 96.4% for ITV_MIP, ITV2, ITV3, and ITV4, respectively. Low ORs were associated with irregular breathing patterns. ITV3s plus 1 mm uniform margins (ITV3+1) led to an average OR of 98.1% and an average RVR of 106.4%. The ITV generated directly from MIP underestimates the range of the respiration motion for esophageal cancer. The ITV generated from 3 phases (ITV3) may be used for regular breathers, whereas the ITV generated from 4 phases (ITV4) or ITV3 plus a 1-mm uniform margin may be applied for irregular breathers. Copyright © 2014 Elsevier Inc. All rights reserved.

Dosimetric evaluation of planning target volume margin reduction for prostate cancer via image-guided intensity-modulated radiation therapy

NASA Astrophysics Data System (ADS)

Hwang, Taejin; Kang, Sei-Kwon; Cheong, Kwang-Ho; Park, Soah; Yoon, Jai-Woong; Han, Taejin; Kim, Haeyoung; Lee, Meyeon; Kim, Kyoung-Joo; Bae, Hoonsik; Suh, Tae-Suk

2015-07-01

The aim of this study was to quantitatively estimate the dosimetric benefits of the image-guided radiation therapy (IGRT) system for the prostate intensity-modulated radiation therapy (IMRT) delivery. The cases of eleven patients who underwent IMRT for prostate cancer without a prostatectomy at our institution between October 2012 and April 2014 were retrospectively analyzed. For every patient, clinical target volume (CTV) to planning target volume (PTV) margins were uniformly used: 3 mm, 5 mm, 7 mm, 10 mm, 12 mm, and 15 mm. For each margin size, the IMRT plans were independently optimized by one medical physicist using Pinnalce3 (ver. 8.0.d, Philips Medical System, Madison, WI) in order to maintain the plan quality. The maximum geometrical margin (MGM) for every CT image set, defined as the smallest margin encompassing the rectum at least at one slice, was between 13 mm and 26 mm. The percentage rectum overlapping PTV (%V ROV ), the rectal normal tissue complication probability (NTCP) and the mean rectal dose (%RD mean ) increased in proportion to the increase of PTV margin. However the bladder NTCP remained around zero to some extent regardless of the increase of PTV margin while the percentage bladder overlapping PTV (%V BOV ) and the mean bladder dose (%BD mean ) increased in proportion to the increase of PTV margin. Without relatively large rectum or small bladder, the increase observed for rectal NTCP, %RDmean and %BD mean per 1-mm PTV margin size were 1.84%, 2.44% and 2.90%, respectively. Unlike the behavior of the rectum or the bladder, the maximum dose on each femoral head had little effect on PTV margin. This quantitative study of the PTV margin reduction supported that IG-IMRT has enhanced the clinical effects over prostate cancer with the reduction of normal organ complications under the similar level of PTV control.

The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy.

PubMed

Clements, N; Kron, T; Franich, R; Dunn, L; Roxby, P; Aarons, Y; Chesson, B; Siva, S; Duplan, D; Ball, D

2013-02-01

Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of this work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment. A Perspex thorax phantom was used to simulate a patient. Three wooden "lung" inserts with embedded Perspex "lesions" were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours. When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when compared to true ITVs. Breathing patterns with a

The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

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

Clements, N.; Kron, T.; Roxby, P.

2013-02-15

Purpose: Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of thismore » work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment. Methods: A Perspex thorax phantom was used to simulate a patient. Three wooden 'lung' inserts with embedded Perspex 'lesions' were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours. Results: When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when compared to

Impact of PET and MRI threshold-based tumor volume segmentation on patient-specific targeted radionuclide therapy dosimetry using CLR1404.

PubMed

Besemer, Abigail E; Titz, Benjamin; Grudzinski, Joseph J; Weichert, Jamey P; Kuo, John S; Robins, H Ian; Hall, Lance T; Bednarz, Bryan P

2017-07-06

Variations in tumor volume segmentation methods in targeted radionuclide therapy (TRT) may lead to dosimetric uncertainties. This work investigates the impact of PET and MRI threshold-based tumor segmentation on TRT dosimetry in patients with primary and metastatic brain tumors. In this study, PET/CT images of five brain cancer patients were acquired at 6, 24, and 48 h post-injection of 124 I-CLR1404. The tumor volume was segmented using two standardized uptake value (SUV) threshold levels, two tumor-to-background ratio (TBR) threshold levels, and a T1 Gadolinium-enhanced MRI threshold. The dice similarity coefficient (DSC), jaccard similarity coefficient (JSC), and overlap volume (OV) metrics were calculated to compare differences in the MRI and PET contours. The therapeutic 131 I-CLR1404 voxel-level dose distribution was calculated from the 124 I-CLR1404 activity distribution using RAPID, a Geant4 Monte Carlo internal dosimetry platform. The TBR, SUV, and MRI tumor volumes ranged from 2.3-63.9 cc, 0.1-34.7 cc, and 0.4-11.8 cc, respectively. The average  ±  standard deviation (range) was 0.19  ±  0.13 (0.01-0.51), 0.30  ±  0.17 (0.03-0.67), and 0.75  ±  0.29 (0.05-1.00) for the JSC, DSC, and OV, respectively. The DSC and JSC values were small and the OV values were large for both the MRI-SUV and MRI-TBR combinations because the regions of PET uptake were generally larger than the MRI enhancement. Notable differences in the tumor dose volume histograms were observed for each patient. The mean (standard deviation) 131 I-CLR1404 tumor doses ranged from 0.28-1.75 Gy GBq -1 (0.07-0.37 Gy GBq -1 ). The ratio of maximum-to-minimum mean doses for each patient ranged from 1.4-2.0. The tumor volume and the interpretation of the tumor dose is highly sensitive to the imaging modality, PET enhancement metric, and threshold level used for tumor volume segmentation. The large variations in tumor doses clearly demonstrate the need for

Impact of PET and MRI threshold-based tumor volume segmentation on patient-specific targeted radionuclide therapy dosimetry using CLR1404

NASA Astrophysics Data System (ADS)

Besemer, Abigail E.; Titz, Benjamin; Grudzinski, Joseph J.; Weichert, Jamey P.; Kuo, John S.; Robins, H. Ian; Hall, Lance T.; Bednarz, Bryan P.

2017-08-01

Variations in tumor volume segmentation methods in targeted radionuclide therapy (TRT) may lead to dosimetric uncertainties. This work investigates the impact of PET and MRI threshold-based tumor segmentation on TRT dosimetry in patients with primary and metastatic brain tumors. In this study, PET/CT images of five brain cancer patients were acquired at 6, 24, and 48 h post-injection of 124I-CLR1404. The tumor volume was segmented using two standardized uptake value (SUV) threshold levels, two tumor-to-background ratio (TBR) threshold levels, and a T1 Gadolinium-enhanced MRI threshold. The dice similarity coefficient (DSC), jaccard similarity coefficient (JSC), and overlap volume (OV) metrics were calculated to compare differences in the MRI and PET contours. The therapeutic 131I-CLR1404 voxel-level dose distribution was calculated from the 124I-CLR1404 activity distribution using RAPID, a Geant4 Monte Carlo internal dosimetry platform. The TBR, SUV, and MRI tumor volumes ranged from 2.3-63.9 cc, 0.1-34.7 cc, and 0.4-11.8 cc, respectively. The average  ±  standard deviation (range) was 0.19  ±  0.13 (0.01-0.51), 0.30  ±  0.17 (0.03-0.67), and 0.75  ±  0.29 (0.05-1.00) for the JSC, DSC, and OV, respectively. The DSC and JSC values were small and the OV values were large for both the MRI-SUV and MRI-TBR combinations because the regions of PET uptake were generally larger than the MRI enhancement. Notable differences in the tumor dose volume histograms were observed for each patient. The mean (standard deviation) 131I-CLR1404 tumor doses ranged from 0.28-1.75 Gy GBq-1 (0.07-0.37 Gy GBq-1). The ratio of maximum-to-minimum mean doses for each patient ranged from 1.4-2.0. The tumor volume and the interpretation of the tumor dose is highly sensitive to the imaging modality, PET enhancement metric, and threshold level used for tumor volume segmentation. The large variations in tumor doses clearly demonstrate the need for standard

Maxillary sinus volume in patients with impacted canines.

PubMed

Oz, Aslihan Zeynep; Oz, Abdullah Alper; El, Hakan; Palomo, Juan Martin

2017-01-01

To evaluate the maxillary sinus volumes in unilaterally impacted canine patients and to compare the volumetric changes that occur after the eruption of canines to the dental arch using cone beam computed tomography (CBCT). Pre- (T0) and posttreatment (T1) CBCT records of 30 patients were used to calculate maxillary sinus volumes between the impacted and erupted canine sides. The InVivoDental 5.0 program was used to measure the volume of the maxillary sinuses. The distance from impacted canine cusp tip to the target point on the palatal plane was also measured. Right maxillary sinus volume was statistically significantly smaller compared to that of the left maxillary sinus when the canine was impacted on the right side at T0. According to the T1 measurements there was no significant difference between the mean volumes of the impaction side and the contralateral side. The distance from the canine tip to its target point on the palatal plane were 17.17 mm, and the distance from the tip to the target point was 15.14 mm for the left- and right-side impacted canines, respectively, and there was a significant difference between the mean amount of change of both sides of maxillary sinuses after treatment of impacted canines. Orthodontic treatment of impacted canines created a significant increase in maxillary sinus volume when the impacted canines were closer with respect to the maxillary sinus.

Nuclear reactor target assemblies, nuclear reactor configurations, and methods for producing isotopes, modifying materials within target material, and/or characterizing material within a target material

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

Toth, James J.; Wall, Donald; Wittman, Richard S.

Target assemblies are provided that can include a uranium-comprising annulus. The assemblies can include target material consisting essentially of non-uranium material within the volume of the annulus. Reactors are disclosed that can include one or more discrete zones configured to receive target material. At least one uranium-comprising annulus can be within one or more of the zones. Methods for producing isotopes within target material are also disclosed, with the methods including providing neutrons to target material within a uranium-comprising annulus. Methods for modifying materials within target material are disclosed as well as are methods for characterizing material within a targetmore » material.« less

Setup Variations in Radiotherapy of Anal Cancer: Advantages of Target Volume Reduction Using Image-Guided Radiation Treatment

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

Chen Yijen, E-mail: yichen@coh.org; Suh, Steve; Nelson, Rebecca A.

2012-09-01

Purpose: To define setup variations in the radiation treatment (RT) of anal cancer and to report the advantages of image-guided RT (IGRT) in terms of reduction of target volume and treatment-related side effects. Methods and Materials: Twelve consecutive patients with anal cancer treated by combined chemoradiation by use of helical tomotherapy from March 2007 to November 2008 were selected. With patients immobilized and positioned in place, megavoltage computed tomography (MVCT) scans were performed before each treatment and were automatically registered to planning CT scans. Patients were shifted per the registration data and treated. A total of 365 MVCT scans weremore » analyzed. The primary site received a median dose of 55 Gy. To evaluate the potential dosimetric advantage(s) of IGRT, cases were replanned according to Radiation Therapy Oncology Group 0529, with and without adding recommended setup variations from the current study. Results: Significant setup variations were observed throughout the course of RT. The standard deviations for systematic setup correction in the anterior-posterior (AP), lateral, and superior-inferior (SI) directions and roll rotation were 1.1, 3.6, and 3.2 mm, and 0.3 Degree-Sign , respectively. The average random setup variations were 3.8, 5.5, and 2.9 mm, and 0.5 Degree-Sign , respectively. Without daily IGRT, margins of 4.9, 11.1, and 8.5 mm in the AP, lateral, and SI directions would have been needed to ensure that the planning target volume (PTV) received {>=}95% of the prescribed dose. Conversely, daily IGRT required no extra margins on PTV and resulted in a significant reduction of V15 and V45 of intestine and V10 of pelvic bone marrow. Favorable toxicities were observed, except for acute hematologic toxicity. Conclusions: Daily MVCT scans before each treatment can effectively detect setup variations and thereby reduce PTV margins in the treatment of anal cancer. The use of concurrent chemotherapy and IGRT provided favorable

Distance-to-Agreement Investigation of Tomotherapy's Bony Anatomy-Based Autoregistration and Planning Target Volume Contour-Based Optimization

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

Suh, Steve, E-mail: ssuh@coh.org; Schultheiss, Timothy E.

Purpose: To compare Tomotherapy's megavoltage computed tomography bony anatomy autoregistration with the best achievable registration, assuming no deformation and perfect knowledge of planning target volume (PTV) location. Methods and Materials: Distance-to-agreement (DTA) of the PTV was determined by applying a rigid-body shift to the PTV region of interest of the prostate from its reference position, assuming no deformations. Planning target volume region of interest of the prostate was extracted from the patient archives. The reference position was set by the 6 degrees of freedom (dof)—x, y, z, roll, pitch, and yaw—optimization results from the previous study at this institution. Themore » DTA and the compensating parameters were calculated by the shift of the PTV from the reference 6-dof to the 4-dof—x, y, z, and roll—optimization. In this study, the effectiveness of Tomotherapy's 4-dof bony anatomy–based autoregistration was compared with the idealized 4-dof PTV contour-based optimization. Results: The maximum DTA (maxDTA) of the bony anatomy-based autoregistration was 3.2 ± 1.9 mm, with the maximum value of 8.0 mm. The maxDTA of the contour-based optimization was 1.8 ± 1.3 mm, with the maximum value of 5.7 mm. Comparison of Pearson correlation of the compensating parameters between the 2 4-dof optimization algorithms shows that there is a small but statistically significant correlation in y and z (0.236 and 0.300, respectively), whereas there is very weak correlation in x and roll (0.062 and 0.025, respectively). Conclusions: We find that there is an average improvement of approximately 1 mm in terms of maxDTA on the PTV going from 4-dof bony anatomy-based autoregistration to the 4-dof contour-based optimization. Pearson correlation analysis of the 2 4-dof optimizations suggests that uncertainties due to deformation and inadequate resolution account for much of the compensating parameters, but pitch variation also makes a statistically

Are We Ready for Positron Emission Tomography/Computed Tomography-based Target Volume Definition in Lymphoma Radiation Therapy?

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

Yeoh, Kheng-Wei; Mikhaeel, N. George, E-mail: George.Mikhaeel@gstt.nhs.uk

2013-01-01

Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has become indispensable for the clinical management of lymphomas. With consistent evidence that it is more accurate than anatomic imaging in the staging and response assessment of many lymphoma subtypes, its utility continues to increase. There have therefore been efforts to incorporate PET/CT data into radiation therapy decision making and in the planning process. Further, there have also been studies investigating target volume definition for radiation therapy using PET/CT data. This article will critically review the literature and ongoing studies on the above topics, examining the value and methods of adding PET/CTmore » data to the radiation therapy treatment algorithm. We will also discuss the various challenges and the areas where more evidence is required.« less

Planned Subtotal Resection of Vestibular Schwannoma Differs from the Ideal Radiosurgical Target Defined by Adaptive Hybrid Surgery.

PubMed

Sheppard, John P; Lagman, Carlito; Prashant, Giyarpuram N; Alkhalid, Yasmine; Nguyen, Thien; Duong, Courtney; Udawatta, Methma; Gaonkar, Bilwaj; Tenn, Stephen E; Bloch, Orin; Yang, Isaac

2018-06-01

To retrospectively compare ideal radiosurgical target volumes defined by a manual method (surgeon) to those determined by Adaptive Hybrid Surgery (AHS) operative planning software in 7 patients with vestibular schwannoma (VS). Four attending surgeons (3 neurosurgeons and 1 ear, nose, and throat surgeon) manually contoured planned residual tumors volumes for 7 consecutive patients with VS. Next, the AHS software determined the ideal radiosurgical target volumes based on a specified radiotherapy plan. Our primary measure was the difference between the average planned residual tumor volumes and the ideal radiosurgical target volumes defined by AHS (dRV AHS-planned ). We included 7 consecutive patients with VS in this study. The planned residual tumor volumes were smaller than the ideal radiosurgical target volumes defined by AHS (1.6 vs. 4.5 cm 3 , P = 0.004). On average, the actual post-operative residual tumor volumes were smaller than the ideal radiosurgical target volumes defined by AHS (2.2 cm 3 vs. 4.5 cm 3 ; P = 0.02). The average difference between the ideal radiosurgical target volume defined by AHS and the planned residual tumor volume (dRV AHS-planned ) was 2.9 ± 1.7 cm 3 , and we observed a trend toward larger dRV AHS-planned in patients who lost serviceable facial nerve function compared with patients who maintained serviceable facial nerve function (4.7 cm 3 vs. 1.9 cm 3 ; P = 0.06). Planned subtotal resection of VS diverges from the ideal radiosurgical target defined by AHS, but whether that influences clinical outcomes is unclear. Copyright © 2018 Elsevier Inc. All rights reserved.

Atlas-based segmentation technique incorporating inter-observer delineation uncertainty for whole breast

NASA Astrophysics Data System (ADS)

Bell, L. R.; Dowling, J. A.; Pogson, E. M.; Metcalfe, P.; Holloway, L.

2017-01-01

Accurate, efficient auto-segmentation methods are essential for the clinical efficacy of adaptive radiotherapy delivered with highly conformal techniques. Current atlas based auto-segmentation techniques are adequate in this respect, however fail to account for inter-observer variation. An atlas-based segmentation method that incorporates inter-observer variation is proposed. This method is validated for a whole breast radiotherapy cohort containing 28 CT datasets with CTVs delineated by eight observers. To optimise atlas accuracy, the cohort was divided into categories by mean body mass index and laterality, with atlas’ generated for each in a leave-one-out approach. Observer CTVs were merged and thresholded to generate an auto-segmentation model representing both inter-observer and inter-patient differences. For each category, the atlas was registered to the left-out dataset to enable propagation of the auto-segmentation from atlas space. Auto-segmentation time was recorded. The segmentation was compared to the gold-standard contour using the dice similarity coefficient (DSC) and mean absolute surface distance (MASD). Comparison with the smallest and largest CTV was also made. This atlas-based auto-segmentation method incorporating inter-observer variation was shown to be efficient (<4min) and accurate for whole breast radiotherapy, with good agreement (DSC>0.7, MASD <9.3mm) between the auto-segmented contours and CTV volumes.

Intra-tumour 18F-FDG uptake heterogeneity decreases the reliability on target volume definition with positron emission tomography/computed tomography imaging.

PubMed

Dong, Xinzhe; Wu, Peipei; Sun, Xiaorong; Li, Wenwu; Wan, Honglin; Yu, Jinming; Xing, Ligang

2015-06-01

This study aims to explore whether the intra-tumour (18) F-fluorodeoxyglucose (FDG) uptake heterogeneity affects the reliability of target volume definition with FDG positron emission tomography/computed tomography (PET/CT) imaging for nonsmall cell lung cancer (NSCLC) and squamous cell oesophageal cancer (SCEC). Patients with NSCLC (n = 50) or SCEC (n = 50) who received (18)F-FDG PET/CT scanning before treatments were included in this retrospective study. Intra-tumour FDG uptake heterogeneity was assessed by visual scoring, the coefficient of variation (COV) of the standardised uptake value (SUV) and the image texture feature (entropy). Tumour volumes (gross tumour volume (GTV)) were delineated on the CT images (GTV(CT)), the fused PET/CT images (GTV(PET-CT)) and the PET images, using a threshold at 40% SUV(max) (GTV(PET40%)) or the SUV cut-off value of 2.5 (GTV(PET2.5)). The correlation between the FDG uptake heterogeneity parameters and the differences in tumour volumes among GTV(CT), GTV(PET-CT), GTV(PET40%) and GTV(PET2.5) was analysed. For both NSCLC and SCEC, obvious correlations were found between uptake heterogeneity, SUV or tumour volumes. Three types of heterogeneity parameters were consistent and closely related to each other. Substantial differences between the four methods of GTV definition were found. The differences between the GTV correlated significantly with PET heterogeneity defined with the visual score, the COV or the textural feature-entropy for NSCLC and SCEC. In tumours with a high FDG uptake heterogeneity, a larger GTV delineation difference was found. Advance image segmentation algorithms dealing with tracer uptake heterogeneity should be incorporated into the treatment planning system. © 2015 The Royal Australian and New Zealand College of Radiologists.

Determination of Internal Target Volume for Radiation Treatment Planning of Esophageal Cancer by Using 4-Dimensional Computed Tomography (4DCT)

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

Chen, Xiaojian; Lu, Haijun; Radiation Oncology Center, Affiliated Hospital of Medical College, Qingdao University, Qingdao

2014-09-01

Purpose: To determine an efficient strategy for the generation of the internal target volume (ITV) for radiation treatment planning for esophageal cancer using 4-dimensional computed tomography (4DCT). Methods and Materials: 4DCT sets acquired for 20 patients with esophageal carcinoma were analyzed. Each of the 4DCT sets was binned into 10 respiratory phases. For each patient, the gross tumor volume (GTV) was delineated on the 4DCT set at each phase. Various strategies to derive ITV were explored, including the volume from the maximum intensity projection (MIP; ITV{sub M}IP), unions of the GTVs from selected multiple phases ITV2 (0% and 50% phases), ITV3 (ITV2more » plus 80%), and ITV4 (ITV3 plus 60%), as well as the volumes expanded from ITV2 and ITV3 with a uniform margin. These ITVs were compared to ITV10 (the union of the GTVs for all 10 phases) and the differences were measured with the overlap ratio (OR) and relative volume ratio (RVR) relative to ITV10 (ITVx/ITV10). Results: For all patients studied, the average GTV from a single phase was 84.9% of ITV10. The average ORs were 91.2%, 91.3%, 94.5%, and 96.4% for ITV{sub M}IP, ITV2, ITV3, and ITV4, respectively. Low ORs were associated with irregular breathing patterns. ITV3s plus 1 mm uniform margins (ITV3+1) led to an average OR of 98.1% and an average RVR of 106.4%. Conclusions: The ITV generated directly from MIP underestimates the range of the respiration motion for esophageal cancer. The ITV generated from 3 phases (ITV3) may be used for regular breathers, whereas the ITV generated from 4 phases (ITV4) or ITV3 plus a 1-mm uniform margin may be applied for irregular breathers.« less

Intensity modulated radiation therapy (IMRT): differences in target volumes and improvement in clinically relevant doses to small bowel in rectal carcinoma.

PubMed

Mok, Henry; Crane, Christopher H; Palmer, Matthew B; Briere, Tina M; Beddar, Sam; Delclos, Marc E; Krishnan, Sunil; Das, Prajnan

2011-06-08

, without incurring penalty with respect to adjacent organs-at-risk. For rectal carcinoma, IMRT, compared to 3DCRT, yielded plans superior with respect to target coverage, homogeneity, and conformality, while lowering dose to adjacent organs-at-risk. This is achieved despite treating larger volumes, raising the possibility of a clinically-relevant improvement in the therapeutic ratio through the use of IMRT with a belly-board apparatus.

VOLUMNECT: measuring volumes with Kinect

NASA Astrophysics Data System (ADS)

Quintino Ferreira, Beatriz; Griné, Miguel; Gameiro, Duarte; Costeira, João. Paulo; Sousa Santos, Beatriz

2014-03-01

This article presents a solution to volume measurement object packing using 3D cameras (such as the Microsoft KinectTM). We target application scenarios, such as warehouses or distribution and logistics companies, where it is important to promptly compute package volumes, yet high accuracy is not pivotal. Our application auto- matically detects cuboid objects using the depth camera data and computes their volume and sorting it allowing space optimization. The proposed methodology applies to a point cloud simple computer vision and image processing methods, as connected components, morphological operations and Harris corner detector, producing encouraging results, namely an accuracy in volume measurement of 8mm. Aspects that can be further improved are identified; nevertheless, the current solution is already promising turning out to be cost effective for the envisaged scenarios.

Transorbital target localization in the porcine model

NASA Astrophysics Data System (ADS)

DeLisi, Michael P.; Mawn, Louise A.; Galloway, Robert L.

2013-03-01

Current pharmacological therapies for the treatment of chronic optic neuropathies such as glaucoma are often inadequate due to their inability to directly affect the optic nerve and prevent neuron death. While drugs that target the neurons have been developed, existing methods of administration are not capable of delivering an effective dose of medication along the entire length of the nerve. We have developed an image-guided system that utilizes a magnetically tracked flexible endoscope to navigate to the back of the eye and administer therapy directly to the optic nerve. We demonstrate the capabilities of this system with a series of targeted surgical interventions in the orbits of live pigs. Target objects consisted of NMR microspherical bulbs with a volume of 18 μL filled with either water or diluted gadolinium-based contrast, and prepared with either the presence or absence of a visible coloring agent. A total of 6 pigs were placed under general anesthesia and two microspheres of differing color and contrast content were blindly implanted in the fat tissue of each orbit. The pigs were scanned with T1-weighted MRI, image volumes were registered, and the microsphere containing gadolinium contrast was designated as the target. The surgeon was required to navigate the flexible endoscope to the target and identify it by color. For the last three pigs, a 2D/3D registration was performed such that the target's coordinates in the image volume was noted and its location on the video stream was displayed with a crosshair to aid in navigation. The surgeon was able to correctly identify the target by color, with an average intervention time of 20 minutes for the first three pigs and 3 minutes for the last three.

Defining the Optimal Planning Target Volume in Image-Guided Stereotactic Radiosurgery of Brain Metastases: Results of a Randomized Trial

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

Kirkpatrick, John P., E-mail: john.kirkpatrick@dm.duke.edu; Department of Surgery, Duke University, Durham, North Carolina; Wang, Zhiheng

2015-01-01

Purpose: To identify an optimal margin about the gross target volume (GTV) for stereotactic radiosurgery (SRS) of brain metastases, minimizing toxicity and local recurrence. Methods and Materials: Adult patients with 1 to 3 brain metastases less than 4 cm in greatest dimension, no previous brain radiation therapy, and Karnofsky performance status (KPS) above 70 were eligible for this institutional review board–approved trial. Individual lesions were randomized to 1- or 3- mm uniform expansion of the GTV defined on contrast-enhanced magnetic resonance imaging (MRI). The resulting planning target volume (PTV) was treated to 24, 18, or 15 Gy marginal dose for maximum PTV diametersmore » less than 2, 2 to 2.9, and 3 to 3.9 cm, respectively, using a linear accelerator–based image-guided system. The primary endpoint was local recurrence (LR). Secondary endpoints included neurocognition Mini-Mental State Examination, Trail Making Test Parts A and B, quality of life (Functional Assessment of Cancer Therapy-Brain), radionecrosis (RN), need for salvage radiation therapy, distant failure (DF) in the brain, and overall survival (OS). Results: Between February 2010 and November 2012, 49 patients with 80 brain metastases were treated. The median age was 61 years, the median KPS was 90, and the predominant histologies were non–small cell lung cancer (25 patients) and melanoma (8). Fifty-five, 19, and 6 lesions were treated to 24, 18, and 15 Gy, respectively. The PTV/GTV ratio, volume receiving 12 Gy or more, and minimum dose to PTV were significantly higher in the 3-mm group (all P<.01), and GTV was similar (P=.76). At a median follow-up time of 32.2 months, 11 patients were alive, with median OS 10.6 months. LR was observed in only 3 lesions (2 in the 1 mm group, P=.51), with 6.7% LR 12 months after SRS. Biopsy-proven RN alone was observed in 6 lesions (5 in the 3-mm group, P=.10). The 12-month DF rate was 45.7%. Three months after SRS, no significant change

Defining the optimal planning target volume in image-guided stereotactic radiosurgery of brain metastases: results of a randomized trial.

PubMed

Kirkpatrick, John P; Wang, Zhiheng; Sampson, John H; McSherry, Frances; Herndon, James E; Allen, Karen J; Duffy, Eileen; Hoang, Jenny K; Chang, Zheng; Yoo, David S; Kelsey, Chris R; Yin, Fang-Fang

2015-01-01

To identify an optimal margin about the gross target volume (GTV) for stereotactic radiosurgery (SRS) of brain metastases, minimizing toxicity and local recurrence. Adult patients with 1 to 3 brain metastases less than 4 cm in greatest dimension, no previous brain radiation therapy, and Karnofsky performance status (KPS) above 70 were eligible for this institutional review board-approved trial. Individual lesions were randomized to 1- or 3- mm uniform expansion of the GTV defined on contrast-enhanced magnetic resonance imaging (MRI). The resulting planning target volume (PTV) was treated to 24, 18, or 15 Gy marginal dose for maximum PTV diameters less than 2, 2 to 2.9, and 3 to 3.9 cm, respectively, using a linear accelerator-based image-guided system. The primary endpoint was local recurrence (LR). Secondary endpoints included neurocognition Mini-Mental State Examination, Trail Making Test Parts A and B, quality of life (Functional Assessment of Cancer Therapy-Brain), radionecrosis (RN), need for salvage radiation therapy, distant failure (DF) in the brain, and overall survival (OS). Between February 2010 and November 2012, 49 patients with 80 brain metastases were treated. The median age was 61 years, the median KPS was 90, and the predominant histologies were non-small cell lung cancer (25 patients) and melanoma (8). Fifty-five, 19, and 6 lesions were treated to 24, 18, and 15 Gy, respectively. The PTV/GTV ratio, volume receiving 12 Gy or more, and minimum dose to PTV were significantly higher in the 3-mm group (all P<.01), and GTV was similar (P=.76). At a median follow-up time of 32.2 months, 11 patients were alive, with median OS 10.6 months. LR was observed in only 3 lesions (2 in the 1 mm group, P=.51), with 6.7% LR 12 months after SRS. Biopsy-proven RN alone was observed in 6 lesions (5 in the 3-mm group, P=.10). The 12-month DF rate was 45.7%. Three months after SRS, no significant change in neurocognition or quality of life was observed. SRS was well

Impact of the introduction of weekly radiotherapy quality assurance meetings at one UK cancer centre.

PubMed

Brammer, C V; Pettit, L; Allerton, R; Churn, M; Joseph, M; Koh, P; Sayers, I; King, M

2014-11-01

The complexity of radiotherapy planning is increasing rapidly. Delivery and planning is subject to detailed quality assurance (QA) checks. The weakest link is often the oncologists' delineation of the clinical target volume (CTV). Weekly departmental meetings for radiotherapy QA (RTQA) were introduced into the Royal Wolverhampton Hospital, Wolverhampton, UK, in October 2011. This article describes the impact of this on patient care. CTVs for megavoltage photon radiotherapy courses for all radical, adjuvant and palliative treatments longer than five fractions (with the exception of two field tangential breast treatments not enrolled into clinical trials) were reviewed in the RTQA meeting. Audits were carried out in January 2012 (baseline) and September 2013, each over a 4-week period. Adherence to departmental contouring protocols was assessed and the number of major and minor alterations following peer review were determined. There was no statistically significant difference for major alterations between the two study groups; 8 alterations in 80 patients (10%) for the baseline audit vs 3 alterations from 72 patients (4.2%) in the second audit (p = 0.17). A trend towards a reduction in alterations following peer review was observed. There has, however, been a change in practice resulting in a reduction in variation in CTV definition within our centre and greater adherence to protocols. There is increasing confidence in the quality and constancy of care delivered. Introduction of a weekly QA meeting for target volume definition has facilitated consensus and adoption of departmental clinical guidelines within the unit. The weakest areas in radiotherapy are patient selection and definition of the CTV. Engagement in high-quality RTQA is paramount. This article describes the impact of this in one UK cancer centre.

Geometric convex cone volume analysis

NASA Astrophysics Data System (ADS)

Li, Hsiao-Chi; Chang, Chein-I.

2016-05-01

Convexity is a major concept used to design and develop endmember finding algorithms (EFAs). For abundance unconstrained techniques, Pixel Purity Index (PPI) and Automatic Target Generation Process (ATGP) which use Orthogonal Projection (OP) as a criterion, are commonly used method. For abundance partially constrained techniques, Convex Cone Analysis is generally preferred which makes use of convex cones to impose Abundance Non-negativity Constraint (ANC). For abundance fully constrained N-FINDR and Simplex Growing Algorithm (SGA) are most popular methods which use simplex volume as a criterion to impose ANC and Abundance Sum-to-one Constraint (ASC). This paper analyze an issue encountered in volume calculation with a hyperplane introduced to illustrate an idea of bounded convex cone. Geometric Convex Cone Volume Analysis (GCCVA) projects the boundary vectors of a convex cone orthogonally on a hyperplane to reduce the effect of background signatures and a geometric volume approach is applied to address the issue arose from calculating volume and further improve the performance of convex cone-based EFAs.

Sphaeropsidin A shows promising activity against drug-resistant cancer cells by targeting regulatory volume increase.

PubMed

Mathieu, Véronique; Chantôme, Aurélie; Lefranc, Florence; Cimmino, Alessio; Miklos, Walter; Paulitschke, Verena; Mohr, Thomas; Maddau, Lucia; Kornienko, Alexander; Berger, Walter; Vandier, Christophe; Evidente, Antonio; Delpire, Eric; Kiss, Robert

2015-10-01

Despite the recent advances in the treatment of tumors with intrinsic chemotherapy resistance, such as melanoma and renal cancers, their prognosis remains poor and new chemical agents with promising activity against these cancers are urgently needed. Sphaeropsidin A, a fungal metabolite whose anticancer potential had previously received little attention, was isolated from Diplodia cupressi and found to display specific anticancer activity in vitro against melanoma and kidney cancer subpanels in the National Cancer Institute (NCI) 60-cell line screen. The NCI data revealed a mean LC50 of ca. 10 µM and a cellular sensitivity profile that did not match that of any other agent in the 765,000 compound database. Subsequent mechanistic studies in melanoma and other multidrug-resistant in vitro cancer models showed that sphaeropsidin A can overcome apoptosis as well as multidrug resistance by inducing a marked and rapid cellular shrinkage related to the loss of intracellular Cl(-) and the decreased HCO3 (-) concentration in the culture supernatant. These changes in ion homeostasis and the absence of effects on the plasma membrane potential were attributed to the sphaeropsidin A-induced impairment of regulatory volume increase (RVI). Preliminary results also indicate that depending on the type of cancer, the sphaeropsidin A effects on RVI could be related to Na-K-2Cl electroneutral cotransporter or Cl(-)/HCO3 (-) anion exchanger(s) targeting. This study underscores the modulation of ion-transporter activity as a promising therapeutic strategy to combat drug-resistant cancers and identifies the fungal metabolite, sphaeropsidin A, as a lead to develop anticancer agents targeting RVI in cancer cells.

Automated linking of suspicious findings between automated 3D breast ultrasound volumes

NASA Astrophysics Data System (ADS)

Gubern-Mérida, Albert; Tan, Tao; van Zelst, Jan; Mann, Ritse M.; Karssemeijer, Nico

2016-03-01

Automated breast ultrasound (ABUS) is a 3D imaging technique which is rapidly emerging as a safe and relatively inexpensive modality for screening of women with dense breasts. However, reading ABUS examinations is very time consuming task since radiologists need to manually identify suspicious findings in all the different ABUS volumes available for each patient. Image analysis techniques to automatically link findings across volumes are required to speed up clinical workflow and make ABUS screening more efficient. In this study, we propose an automated system to, given the location in the ABUS volume being inspected (source), find the corresponding location in a target volume. The target volume can be a different view of the same study or the same view from a prior examination. The algorithm was evaluated using 118 linkages between suspicious abnormalities annotated in a dataset of ABUS images of 27 patients participating in a high risk screening program. The distance between the predicted location and the center of the annotated lesion in the target volume was computed for evaluation. The mean ± stdev and median distance error achieved by the presented algorithm for linkages between volumes of the same study was 7.75±6.71 mm and 5.16 mm, respectively. The performance was 9.54±7.87 and 8.00 mm (mean ± stdev and median) for linkages between volumes from current and prior examinations. The proposed approach has the potential to minimize user interaction for finding correspondences among ABUS volumes.

Atlas-based automatic segmentation of head and neck organs at risk and nodal target volumes: a clinical validation.

PubMed

Daisne, Jean-François; Blumhofer, Andreas

2013-06-26

Intensity modulated radiotherapy for head and neck cancer necessitates accurate definition of organs at risk (OAR) and clinical target volumes (CTV). This crucial step is time consuming and prone to inter- and intra-observer variations. Automatic segmentation by atlas deformable registration may help to reduce time and variations. We aim to test a new commercial atlas algorithm for automatic segmentation of OAR and CTV in both ideal and clinical conditions. The updated Brainlab automatic head and neck atlas segmentation was tested on 20 patients: 10 cN0-stages (ideal population) and 10 unselected N-stages (clinical population). Following manual delineation of OAR and CTV, automatic segmentation of the same set of structures was performed and afterwards manually corrected. Dice Similarity Coefficient (DSC), Average Surface Distance (ASD) and Maximal Surface Distance (MSD) were calculated for "manual to automatic" and "manual to corrected" volumes comparisons. In both groups, automatic segmentation saved about 40% of the corresponding manual segmentation time. This effect was more pronounced for OAR than for CTV. The edition of the automatically obtained contours significantly improved DSC, ASD and MSD. Large distortions of normal anatomy or lack of iodine contrast were the limiting factors. The updated Brainlab atlas-based automatic segmentation tool for head and neck Cancer patients is timesaving but still necessitates review and corrections by an expert.

[Definition of nodal volumes in breast cancer treatment and segmentation guidelines].

PubMed

Kirova, Y M; Castro Pena, P; Dendale, R; Campana, F; Bollet, M A; Fournier-Bidoz, N; Fourquet, A

2009-06-01

To assist in the determination of breast and nodal volumes in the setting of radiotherapy for breast cancer and establish segmentation guidelines. Materials and methods. Contrast metarial enhanced CT examinations were obtained in the treatment position in 25 patients to clearly define the target volumes. The clinical target volume (CTV) including the breast, internal mammary nodes, supraclavicular and subclavicular regions and axxilary region were segmented along with the brachial plexus and interpectoral nodes. The following critical organs were also segmented: heart, lungs, contralateral breast, thyroid, esophagus and humeral head. A correlation between clinical and imaging findings and meeting between radiation oncologists and breast specialists resulted in a better definition of irradiation volumes for breast and nodes with establishement of segmentation guidelines and creation of an anatomical atlas. A practical approach, based on anatomical criteria, is proposed to assist in the segmentation of breast and node volumes in the setting of breast cancer treatment along with a definition of irradiation volumes.

Fast patient-specific Monte Carlo brachytherapy dose calculations via the correlated sampling variance reduction technique

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

Sampson, Andrew; Le Yi; Williamson, Jeffrey F.

2012-02-15

Purpose: To demonstrate potential of correlated sampling Monte Carlo (CMC) simulation to improve the calculation efficiency for permanent seed brachytherapy (PSB) implants without loss of accuracy. Methods: CMC was implemented within an in-house MC code family (PTRAN) and used to compute 3D dose distributions for two patient cases: a clinical PSB postimplant prostate CT imaging study and a simulated post lumpectomy breast PSB implant planned on a screening dedicated breast cone-beam CT patient exam. CMC tallies the dose difference, {Delta}D, between highly correlated histories in homogeneous and heterogeneous geometries. The heterogeneous geometry histories were derived from photon collisions sampled inmore » a geometrically identical but purely homogeneous medium geometry, by altering their particle weights to correct for bias. The prostate case consisted of 78 Model-6711 {sup 125}I seeds. The breast case consisted of 87 Model-200 {sup 103}Pd seeds embedded around a simulated lumpectomy cavity. Systematic and random errors in CMC were unfolded using low-uncertainty uncorrelated MC (UMC) as the benchmark. CMC efficiency gains, relative to UMC, were computed for all voxels, and the mean was classified in regions that received minimum doses greater than 20%, 50%, and 90% of D{sub 90}, as well as for various anatomical regions. Results: Systematic errors in CMC relative to UMC were less than 0.6% for 99% of the voxels and 0.04% for 100% of the voxels for the prostate and breast cases, respectively. For a 1 x 1 x 1 mm{sup 3} dose grid, efficiency gains were realized in all structures with 38.1- and 59.8-fold average gains within the prostate and breast clinical target volumes (CTVs), respectively. Greater than 99% of the voxels within the prostate and breast CTVs experienced an efficiency gain. Additionally, it was shown that efficiency losses were confined to low dose regions while the largest gains were located where little difference exists between the homogeneous

[Target volume segmentation of PET images by an iterative method based on threshold value].

PubMed

Castro, P; Huerga, C; Glaría, L A; Plaza, R; Rodado, S; Marín, M D; Mañas, A; Serrada, A; Núñez, L

2014-01-01

An automatic segmentation method is presented for PET images based on an iterative approximation by threshold value that includes the influence of both lesion size and background present during the acquisition. Optimal threshold values that represent a correct segmentation of volumes were determined based on a PET phantom study that contained different sizes spheres and different known radiation environments. These optimal values were normalized to background and adjusted by regression techniques to a two-variable function: lesion volume and signal-to-background ratio (SBR). This adjustment function was used to build an iterative segmentation method and then, based in this mention, a procedure of automatic delineation was proposed. This procedure was validated on phantom images and its viability was confirmed by retrospectively applying it on two oncology patients. The resulting adjustment function obtained had a linear dependence with the SBR and was inversely proportional and negative with the volume. During the validation of the proposed method, it was found that the volume deviations respect to its real value and CT volume were below 10% and 9%, respectively, except for lesions with a volume below 0.6 ml. The automatic segmentation method proposed can be applied in clinical practice to tumor radiotherapy treatment planning in a simple and reliable way with a precision close to the resolution of PET images. Copyright © 2013 Elsevier España, S.L.U. and SEMNIM. All rights reserved.

Volumetric-modulated arc therapy for the treatment of a large planning target volume in thoracic esophageal cancer.

PubMed

Abbas, Ahmar S; Moseley, Douglas; Kassam, Zahra; Kim, Sun Mo; Cho, Charles

2013-05-06

Recently, volumetric-modulated arc therapy (VMAT) has demonstrated the ability to deliver radiation dose precisely and accurately with a shorter delivery time compared to conventional intensity-modulated fixed-field treatment (IMRT). We applied the hypothesis of VMAT technique for the treatment of thoracic esophageal carcinoma to determine superior or equivalent conformal dose coverage for a large thoracic esophageal planning target volume (PTV) with superior or equivalent sparing of organs-at-risk (OARs) doses, and reduce delivery time and monitor units (MUs), in comparison with conventional fixed-field IMRT plans. We also analyzed and compared some other important metrics of treatment planning and treatment delivery for both IMRT and VMAT techniques. These metrics include: 1) the integral dose and the volume receiving intermediate dose levels between IMRT and VMATI plans; 2) the use of 4D CT to determine the internal motion margin; and 3) evaluating the dosimetry of every plan through patient-specific QA. These factors may impact the overall treatment plan quality and outcomes from the individual planning technique used. In this study, we also examined the significance of using two arcs vs. a single-arc VMAT technique for PTV coverage, OARs doses, monitor units and delivery time. Thirteen patients, stage T2-T3 N0-N1 (TNM AJCC 7th edn.), PTV volume median 395 cc (range 281-601 cc), median age 69 years (range 53 to 85), were treated from July 2010 to June 2011 with a four-field (n = 4) or five-field (n = 9) step-and-shoot IMRT technique using a 6 MV beam to a prescribed dose of 50 Gy in 20 to 25 F. These patients were retrospectively replanned using single arc (VMATI, 91 control points) and two arcs (VMATII, 182 control points). All treatment plans of the 13 study cases were evaluated using various dose-volume metrics. These included PTV D99, PTV D95, PTV V9547.5Gy(95%), PTV mean dose, Dmax, PTV dose conformity (Van't Riet conformation number (CN)), mean lung dose

Volumetric‐modulated arc therapy for the treatment of a large planning target volume in thoracic esophageal cancer

PubMed Central

Moseley, Douglas; Kassam, Zahra; Kim, Sun Mo; Cho, Charles

2013-01-01

Recently, volumetric‐modulated arc therapy (VMAT) has demonstrated the ability to deliver radiation dose precisely and accurately with a shorter delivery time compared to conventional intensity‐modulated fixed‐field treatment (IMRT). We applied the hypothesis of VMAT technique for the treatment of thoracic esophageal carcinoma to determine superior or equivalent conformal dose coverage for a large thoracic esophageal planning target volume (PTV) with superior or equivalent sparing of organs‐at‐risk (OARs) doses, and reduce delivery time and monitor units (MUs), in comparison with conventional fixed‐field IMRT plans. We also analyzed and compared some other important metrics of treatment planning and treatment delivery for both IMRT and VMAT techniques. These metrics include: 1) the integral dose and the volume receiving intermediate dose levels between IMRT and VMATI plans; 2) the use of 4D CT to determine the internal motion margin; and 3) evaluating the dosimetry of every plan through patient‐specific QA. These factors may impact the overall treatment plan quality and outcomes from the individual planning technique used. In this study, we also examined the significance of using two arcs vs. a single‐arc VMAT technique for PTV coverage, OARs doses, monitor units and delivery time. Thirteen patients, stage T2‐T3 N0‐N1 (TNM AJCC 7th edn.), PTV volume median 395 cc (range 281–601 cc), median age 69 years (range 53 to 85), were treated from July 2010 to June 2011 with a four‐field (n=4) or five‐field (n=9) step‐and‐shoot IMRT technique using a 6 MV beam to a prescribed dose of 50 Gy in 20 to 25 F. These patients were retrospectively replanned using single arc (VMATI, 91 control points) and two arcs (VMATII, 182 control points). All treatment plans of the 13 study cases were evaluated using various dose‐volume metrics. These included PTV D99, PTV D95, PTV V9547.5Gy(95%), PTV mean dose, Dmax, PTV dose conformity (Van't Riet conformation

Voluntary Deep Inspiration Breath-hold Reduces the Heart Dose Without Compromising the Target Volume Coverage During Radiotherapy for Left-sided Breast Cancer.

PubMed

Al-Hammadi, Noora; Caparrotti, Palmira; Naim, Carole; Hayes, Jillian; Rebecca Benson, Katherine; Vasic, Ana; Al-Abdulla, Hissa; Hammoud, Rabih; Divakar, Saju; Petric, Primoz

2018-03-01

During radiotherapy of left-sided breast cancer, parts of the heart are irradiated, which may lead to late toxicity. We report on the experience of single institution with cardiac-sparing radiotherapy using voluntary deep inspiration breath hold (V-DIBH) and compare its dosimetric outcome with free breathing (FB) technique. Left-sided breast cancer patients, treated at our department with postoperative radiotherapy of breast/chest wall +/- regional lymph nodes between May 2015 and January 2017, were considered for inclusion. FB-computed tomography (CT) was obtained and dose-planning performed. Cases with cardiac V25Gy ≥ 5% or risk factors for heart disease were coached for V-DIBH. Compliant patients were included. They underwent additional CT in V-DIBH for planning, followed by V-DIBH radiotherapy. Dose volume histogram parameters for heart, lung and optimized planning target volume (OPTV) were compared between FB and BH. Treatment setup shifts and systematic and random errors for V-DIBH technique were compared with FB historic control. Sixty-three patients were considered for V-DIBH. Nine (14.3%) were non-compliant at coaching, leaving 54 cases for analysis. When compared with FB, V-DIBH resulted in a significant reduction of mean cardiac dose from 6.1 +/- 2.5 to 3.2 +/- 1.4 Gy (p < 0.001), maximum cardiac dose from 51.1 +/- 1.4 to 48.5 +/- 6.8 Gy (p = 0.005) and cardiac V25Gy from 8.5 +/- 4.2 to 3.2 +/- 2.5% (p < 0.001). Heart volumes receiving low (10-20 Gy) and high (30-50 Gy) doses were also significantly reduced. Mean dose to the left anterior coronary artery was 23.0 (+/- 6.7) Gy and 14.8 (+/- 7.6) Gy on FB and V-DIBH, respectively (p < 0.001). Differences between FB- and V-DIBH-derived mean lung dose (11.3 +/- 3.2 vs. 10.6 +/- 2.6 Gy), lung V20Gy (20.5 +/- 7 vs. 19.5 +/- 5.1 Gy) and V95% for the OPTV (95.6 +/- 4.1 vs. 95.2 +/- 6.3%) were non-significant. V-DIBH-derived mean shifts for initial patient setup were ≤ 2.7 mm. Random and systematic errors

Sphere of equivalence--a novel target volume concept for intraoperative radiotherapy using low-energy X rays.

PubMed

Herskind, Carsten; Griebel, Jürgen; Kraus-Tiefenbacher, Uta; Wenz, Frederik

2008-12-01

Accelerated partial breast radiotherapy with low-energy photons from a miniature X-ray machine is undergoing a randomized clinical trial (Targeted Intra-operative Radiation Therapy [TARGIT]) in a selected subgroup of patients treated with breast-conserving surgery. The steep radial dose gradient implies reduced tumor cell control with increasing depth in the tumor bed. The purpose was to compare the expected risk of local recurrence in this nonuniform radiation field with that after conventional external beam radiotherapy. The relative biologic effectiveness of low-energy photons was modeled using the linear-quadratic formalism including repair of sublethal lesions during protracted irradiation. Doses of 50-kV X-rays (Intrabeam) were converted to equivalent fractionated doses, EQD2, as function of depth in the tumor bed. The probability of local control was estimated using a logistic dose-response relationship fitted to clinical data from fractionated radiotherapy. The model calculations show that, for a cohort of patients, the increase in local control in the high-dose region near the applicator partly compensates the reduction of local control at greater distances. Thus a "sphere of equivalence" exists within which the risk of recurrence is equal to that after external fractionated radiotherapy. The spatial distribution of recurrences inside this sphere will be different from that after conventional radiotherapy. A novel target volume concept is presented here. The incidence of recurrences arising in the tumor bed around the excised tumor will test the validity of this concept and the efficacy of the treatment. Recurrences elsewhere will have implications for the rationale of TARGIT.

Use of biotin targeted methotrexate–human serum albumin conjugated nanoparticles to enhance methotrexate antitumor efficacy

PubMed Central

Taheri, Azade; Dinarvand, Rassoul; Nouri, Faranak Salman; Khorramizadeh, Mohammad Reza; Borougeni, Atefeh Taheri; Mansoori, Pooria; Atyabi, Fatemeh

2011-01-01

Biotin molecules could be used as suitable targeting moieties in targeted drug delivery systems against tumors. To develop a biotin targeted drug delivery system, we employed human serum albumin (HSA) as a carrier. Methotrexate (MTX) molecules were conjugated to HSA. MTX-HSA nanoparticles (MTX-HSA NPs) were prepared from these conjugates by cross-linking the HSA molecules. Biotin molecules were then conjugated on the surface of MTX-HSA NPs. The anticancer efficacy of biotin targeted MTX-HSA NPs was evaluated in mice bearing 4T1 breast carcinoma. A single dose of biotin targeted MTX-HSA NPs showed stronger in vivo antitumor activity than non-targeted MTX-HSA NPs and free MTX. By 7 days after treatment, average tumor volume in the biotin targeted MTX-HSA NPs-treated group decreased to 17.6% of the initial tumor volume when the number of attached biotin molecules on MTX-HSA-NPs was the highest. Average tumor volume in non-targeted MTX-HSA NPs-treated mice grew rapidly and reached 250.7% of the initial tumor volume. Biotin targeted MTX-HSA NPs increased the survival of tumor-bearing mice to 47.5 ± 0.71 days and increased their life span up to 216.7%. Mice treated with biotin targeted MTX-HSA NPs showed slight body weight loss (8%) 21 days after treatment, whereas non-targeted MTX-HSA NPs treatment at the same dose caused a body weight loss of 27.05% ± 3.1%. PMID:21931482

Glioma targeting and blood-brain barrier penetration by dual-targeting doxorubincin liposomes.

PubMed

Gao, Jian-Qing; Lv, Qing; Li, Li-Ming; Tang, Xin-Jiang; Li, Fan-Zhu; Hu, Yu-Lan; Han, Min

2013-07-01

Effective chemotherapy for glioblastoma requires a carrier that can penetrate the blood-brain barrier (BBB) and subsequently target the glioma cells. Dual-targeting doxorubincin (Dox) liposomes were produced by conjugating liposomes with both folate (F) and transferrin (Tf), which were proven effective in penetrating the BBB and targeting tumors, respectively. The liposome was characterized by particle size, Dox entrapment efficiency, and in vitro release profile. Drug accumulation in cells, P-glycoprotein (P-gp) expression, and drug transport across the BBB in the dual-targeting liposome group were examined by using bEnd3 BBB models. In vivo studies demonstrated that the dual-targeting Dox liposomes could transport across the BBB and mainly distribute in the brain glioma. The anti-tumor effect of the dual-targeting liposome was also demonstrated by the increased survival time, decreased tumor volume, and results of both hematoxylin-eosin staining and terminal deoxynucleotidyl transferase dUTP nick end labeling analysis. The dual-targeting Dox liposome could improve the therapeutic efficacy of brain glioma and were less toxic than the Dox solution, showing a dual-targeting effect. These results indicate that this dual-targeting liposome can be used as a potential carrier for glioma chemotherapy. Copyright © 2013 Elsevier Ltd. All rights reserved.

The influence of RBE variations in a clinical proton treatment plan for a hypopharynx cancer

NASA Astrophysics Data System (ADS)

Tilly, N.; Johansson, J.; Isacsson, U.; Medin, J.; Blomquist, E.; Grusell, E.; Glimelius, B.

2005-06-01

Currently, most clinical range-modulated proton beams are assumed to have a fixed overall relative biological effectiveness (RBE) of 1.1. However, it is well known that the RBE increases with depth in the spread-out Bragg peak (SOBP) and becomes about 10% higher than mid-SOBP RBE at 2 mm from the distal edge (Paganetti 2003 Technol. Cancer Res. Treat. 2 413-26) and can reach values of 1.3-1.4 in vitro at the distal edge (Robertson et al 1975 Cancer 35 1664-77, Courdi et al 1994 Br. J. Radiol. 67 800-4). We present a fast method for applying a variable RBE correction with linear energy transfer (LET) dependent tissue-specific parameters based on the αref/βref ratios suitable for implementation in a treatment planning system. The influence of applying this variable RBE correction on a clinical multiple beam proton dose plan is presented here. The treatment plan is evaluated by RBE weighted dose volume histograms (DVHs) and the calculation of tumour control probability (TCP) and normal tissue complication probability (NTCP) values. The variable RBE correction yields DVHs for the clinical target volumes (CTVs), a primary advanced hypopharynx cancer and subclinical disease in the lymph nodes, that are slightly higher than those achieved by multiplying the absorbed dose with RBE = 1.1. Although, more importantly, the RBE weighted DVH for an organ at risk, the spinal cord is considerably increased for the variable RBE. As the spinal cord in this particular case is located 8 mm behind the planning target volume (PTV) and hence receives only low total doses, the NTCP values are zero in spite of the significant increase in the RBE weighted DVHs for the variable RBE. However, high NTCP values for the non-target normal tissue were obtained when applying the variable RBE correction. As RBE variations tend to be smaller for in vivo systems, this study—based on in vitro data since human tissue RBE values are scarce and have large uncertainties—can be interpreted as showing

Elasticity-based three dimensional ultrasound real-time volume rendering

NASA Astrophysics Data System (ADS)

Boctor, Emad M.; Matinfar, Mohammad; Ahmad, Omar; Rivaz, Hassan; Choti, Michael; Taylor, Russell H.

2009-02-01

Volumetric ultrasound imaging has not gained wide recognition, despite the availability of real-time 3D ultrasound scanners and the anticipated potential of 3D ultrasound imaging in diagnostic and interventional radiology. Their use, however, has been hindered by the lack of real-time visualization methods that are capable of producing high quality 3D rendering of the target/surface of interest. Volume rendering is a known visualization method, which can display clear surfaces out of the acquired volumetric data, and has an increasing number of applications utilizing CT and MRI data. The key element of any volume rendering pipeline is the ability to classify the target/surface of interest by setting an appropriate opacity function. Practical and successful real-time 3D ultrasound volume rendering can be achieved in Obstetrics and Angio applications where setting these opacity functions can be done rapidly, and reliably. Unfortunately, 3D ultrasound volume rendering of soft tissues is a challenging task due to the presence of significant amount of noise and speckle. Recently, several research groups have shown the feasibility of producing 3D elasticity volume from two consecutive 3D ultrasound scans. This report describes a novel volume rendering pipeline utilizing elasticity information. The basic idea is to compute B-mode voxel opacity from the rapidly calculated strain values, which can also be mixed with conventional gradient based opacity function. We have implemented the volume renderer using GPU unit, which gives an update rate of 40 volume/sec.

Target volume definition for post prostatectomy radiotherapy: Do the consensus guidelines correctly define the inferior border of the CTV?

PubMed

Manji, Mo; Crook, Juanita; Schmid, Matt; Rajapakshe, Rasika

2016-01-01

We compare urethrogram delineation of the caudal aspect of the anastomosis to the recommended guidelines of post prostatectomy radiotherapy. Level one evidence has established the indications for, and importance of, adjuvant radiotherapy following radical prostatectomy. Several guidelines have recently addressed delineation of the prostate bed target volume including identification of the vesico-urethral anastomosis, taken as the first CT slice caudal to visible urine in the bladder neck. The inferior border of clinical target volume is then variably defined 5-12 mm below this anastomosis or 15 mm cranial to the penile bulb. Thirty-three patients who received adjuvant radiotherapy following radical prostatectomy were reviewed. All underwent planning CT with urethrogram. The authors (MM, JC) independently identified the CT slice caudal to the last slice showing urine in the bladder neck (called the CT Reference Slice), and measured the distance between this and the tip of the urethrogram cone. Five patients also had a diagnostic MRI at the time of CT planning to better visualize the anatomy. Sixty-six readings were obtained. The mean distance between the Bladder CT Reference Slice and the most cranial urethrogram contrast slice was 16.1 mm (MM 16.4 mm, JC 15.8 mm), range: 6.8-34.2 mm. The mean distance between the urethrogram tip and the ischial tuberosities was 19.9 mm (range 12.5-29.8 mm). The mean distance between the CT Reference Slice and the ischial tuberosities was 36.9 mm (range 28.3-52.4 mm). Guidelines for prostate bed radiation post prostatectomy have been developed after publication of the trials proving benefit of such treatment, and are thus untested. The anastomosis is a frequent site of local relapse but is variably defined by the existing guidelines, none of which take into account anatomic patient variation and all of which are at variance with urethrogram data. We recommend the use of planning urethrogram to better delineate the vesico

The role of PET in target localization for radiotherapy treatment planning.

PubMed

Rembielak, Agata; Price, Pat

2008-02-01

Positron emission tomography (PET) is currently accepted as an important tool in oncology, mostly for diagnosis, staging and restaging purposes. It provides a new type of information in radiotherapy, functional rather than anatomical. PET imaging can also be used for target volume definition in radiotherapy treatment planning. The need for very precise target volume delineation has arisen with the increasing use of sophisticated three-dimensional conformal radiotherapy techniques and intensity modulated radiation therapy. It is expected that better delineation of the target volume may lead to a significant reduction in the irradiated volume, thus lowering the risk of treatment complications (smaller safety margins). Better tumour visualisation also allows a higher dose of radiation to be applied to the tumour, which may lead to better tumour control. The aim of this article is to review the possible use of PET imaging in the radiotherapy of various cancers. We focus mainly on non-small cell lung cancer, lymphoma and oesophageal cancer, but also include current opinion on the use of PET-based planning in other tumours including brain, uterine cervix, rectum and prostate.

Therapeutic analysis of high-dose-rate {sup 192}Ir vaginal cuff brachytherapy for endometrial cancer using a cylindrical target volume model and varied cancer cell distributions

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

Zhang, Hualin, E-mail: hualin.zhang@northwestern.edu; Donnelly, Eric D.; Strauss, Jonathan B.

Purpose: To evaluate high-dose-rate (HDR) vaginal cuff brachytherapy (VCBT) in the treatment of endometrial cancer in a cylindrical target volume with either a varied or a constant cancer cell distributions using the linear quadratic (LQ) model. Methods: A Monte Carlo (MC) technique was used to calculate the 3D dose distribution of HDR VCBT over a variety of cylinder diameters and treatment lengths. A treatment planning system (TPS) was used to make plans for the various cylinder diameters, treatment lengths, and prescriptions using the clinical protocol. The dwell times obtained from the TPS were fed into MC. The LQ model wasmore » used to evaluate the therapeutic outcome of two brachytherapy regimens prescribed either at 0.5 cm depth (5.5 Gy × 4 fractions) or at the vaginal mucosal surface (8.8 Gy × 4 fractions) for the treatment of endometrial cancer. An experimentally determined endometrial cancer cell distribution, which showed a varied and resembled a half-Gaussian distribution, was used in radiobiology modeling. The equivalent uniform dose (EUD) to cancer cells was calculated for each treatment scenario. The therapeutic ratio (TR) was defined by comparing VCBT with a uniform dose radiotherapy plan in term of normal cell survival at the same level of cancer cell killing. Calculations of clinical impact were run twice assuming two different types of cancer cell density distributions in the cylindrical target volume: (1) a half-Gaussian or (2) a uniform distribution. Results: EUDs were weakly dependent on cylinder size, treatment length, and the prescription depth, but strongly dependent on the cancer cell distribution. TRs were strongly dependent on the cylinder size, treatment length, types of the cancer cell distributions, and the sensitivity of normal tissue. With a half-Gaussian distribution of cancer cells which populated at the vaginal mucosa the most, the EUDs were between 6.9 Gy × 4 and 7.8 Gy × 4, the TRs were in the range from (5.0){sup 4} to

Generation of Parametric Equivalent-Area Targets for Design of Low-Boom Supersonic Concepts

NASA Technical Reports Server (NTRS)

Li, Wu; Shields, Elwood

2011-01-01

A tool with an Excel visual interface is developed to generate equivalent-area (A(sub e)) targets that satisfy the volume constraints for a low-boom supersonic configuration. The new parametric Ae target explorer allows users to interactively study the tradeoffs between the aircraft volume constraints and the low-boom characteristics (e.g., loudness) of the ground signature. Moreover, numerical optimization can be used to generate the optimal A(sub e) target for given A(sub e) volume constraints. A case study is used to demonstrate how a generated low-boom Ae target can be matched by a supersonic configuration that includes a fuselage, wing, nacelle, pylon, aft pod, horizontal tail, and vertical tail. The low-boom configuration is verified by sonic-boom analysis with an off-body pressure distribution at three body lengths below the configuration

LLE Review Quarterly Report (October - December 2007). Volume 113

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

Zuegel, Jonathan D.

2007-12-01

This volume of the LLE Review, covering October–December 2007, features “High-Intensity Laser–Plasma Interactions in the Refluxing Limit,” by P. M. Nilson, W. Theobald, J. Myatt, C. Stoeckl, M. Storm, O. V. Gotchev, J. D. Zuegel, R. Betti, D. D. Meyerhofer, and T. C. Sangster. In this article (p. 1), the authors report on target experiments using the Multi-Terawatt (MTW) Laser Facility to study isochoric heating of solid-density targets by fast electrons produced from intense, short-pulse laser irradiation. Electron refluxing occurs due to target-sheath field effects and contains most of the fast electrons within the target volume. This efficiently heats themore » solid-density plasma through collisions. X-ray spectroscopic measurements of absolute K α (x-radiation) photon yields and variations of the K β/K α b emission ratio both indicate that laser energy couples to fast electrons with a conversion efficiency of approximately 20%. Bulk electron temperatures of at least 200 eV are inferred for the smallest mass targets.« less

Patterns-of-failure guided biological target volume definition for head and neck cancer patients: FDG-PET and dosimetric analysis of dose escalation candidate subregions.

PubMed

Mohamed, Abdallah S R; Cardenas, Carlos E; Garden, Adam S; Awan, Musaddiq J; Rock, Crosby D; Westergaard, Sarah A; Brandon Gunn, G; Belal, Abdelaziz M; El-Gowily, Ahmed G; Lai, Stephen Y; Rosenthal, David I; Fuller, Clifton D; Aristophanous, Michalis

2017-08-01

To identify the radio-resistant subvolumes in pretreatment FDG-PET by mapping the spatial location of the origin of tumor recurrence after IMRT for head-and-neck squamous cell cancer to the pretreatment FDG-PET/CT. Patients with local/regional recurrence after IMRT with available FDG-PET/CT and post-failure CT were included. For each patient, both pre-therapy PET/CT and recurrence CT were co-registered with the planning CT (pCT). A 4-mm radius was added to the centroid of mapped recurrence growth target volumes (rGTV's) to create recurrence nidus-volumes (NVs). The overlap between boost-tumor-volumes (BTV) representing different SUV thresholds/margins combinations and NVs was measured. Forty-seven patients were eligible. Forty-two (89.4%) had type A central high dose failure. Twenty-six (48%) of type A rGTVs were at the primary site and 28 (52%) were at the nodal site. The mean dose of type A rGTVs was 71Gy. BTV consisting of 50% of the maximum SUV plus 10mm margin was the best subvolume for dose boosting due to high coverage of primary site NVs (92.3%), low average relative volume to CTV1 (41%), and least average percent voxels outside CTV1 (19%). The majority of loco-regional recurrences originate in the regions of central-high-dose. When correlated with pretreatment FDG-PET, the majority of recurrences originated in an area that would be covered by additional 10mm margin on the volume of 50% of the maximum FDG uptake. Copyright © 2017 Elsevier B.V. All rights reserved.

Pragmatics & Language Learning. Volume 12

ERIC Educational Resources Information Center

Kasper, Gabriele, Ed.; Nguyen, Hanh thi, Ed.; Yoshimi, Dina Rudolph, Ed.; Yoshioka, Jim K., Ed.

2010-01-01

This volume examines the organization of second language and multilingual speakers' talk and pragmatic knowledge across a range of naturalistic and experimental activities. Based on data collected on Danish, English, Hawai'i Creole, Indonesian, and Japanese as target languages, the contributions explore the nexus of pragmatic knowledge,…

Is a Clinical Target Volume (CTV) Necessary in the Treatment of Lung Cancer in the Modern Era Combining 4-D Imaging and Image-guided Radiotherapy (IGRT)?

PubMed

Kilburn, Jeremy M; Lucas, John T; Soike, Michael H; Ayala-Peacock, Diandra N; Blackstock, Arthur W; Hinson, William H; Munley, Michael T; Petty, William J; Urbanic, James J

2016-01-23

We hypothesized that omission of clinical target volumes (CTV) in lung cancer radiotherapy would not compromise control by determining retrospectively if the addition of a CTV would encompass the site of failure. Stage II-III patients were treated from 2009-2012 with daily cone-beam imaging and a 5 mm planning target volume (PTV) without a CTV. PTVs were expanded 1 cm and termed CTVretro. Recurrences were scored as 1) within the PTV, 2) within CTVretro, or 3) outside the PTV. Locoregional control (LRC), distant control (DC), progression-free survival (PFS), and overall survival (OS) were estimated. Among 110 patients, Stage IIIA 57%, IIIB 32%, IIA 4%, and IIB 7%. Eighty-six percent of Stage III patients received chemotherapy. Median dose was 70 Gy (45-74 Gy) and fraction size ranged from 1.5-2.7 Gy. Median follow-up was 12 months, median OS was 22 months (95% CI 19-30 months), and LRC at two years was 69%. Fourteen local and eight regional events were scored with two CTVretro failures equating to a two-year CTV failure-free survival of 98%. Omission of a 1 cm CTV expansion appears feasible based on only two events among 110 patients and should be considered in radiation planning.

Definition of the key target volume in radiosurgical management of arteriovenous malformations: a new dynamic concept based on angiographic circulation time.

PubMed

Valle, Ramiro Del; Zenteno, Marco; Jaramillo, José; Lee, Angel; De Anda, Salvador

2008-12-01

The cumulative experience worldwide indicates complete radiosurgical obliteration rates of brain arteriovenous malformations (AVMs) ranging from 35 to 90%. The purpose of this study was to propose a strategy to increase the obliteration rate for AVMs through the dynamic definition of the key target volume (KTV). A prospective series of patients harboring an AVM was assessed using digital subtraction angiography in which a digital counter was used to measure the several stages of the frame-by-frame circulation time. All the patients were analyzed using dynamic measurement planning to define the KTV, corresponding to the volume of the shunt with the least vascular resistance and the earliest venous drainage. All patients underwent catheter-based angiography, a subgroup was additionally assessed by means of a superselective catheterization, and among these a further subgroup received embolization. The shunts were also categorized according to their angioarchitectural type: fistulous, plexiform, or mixed. The authors applied the radiosurgery-based grading system (RBGS) as well to find a correlation with the obliteration rate. This series includes 44 patients treated by radiosurgery; global angiography was performed for all patients, including dynamic measurement planning. Eighty-four percent of them underwent superselective catheterization, and 50% of the total population underwent embolization. In the embolized arm of the study, the pretreatment volume was up to 120 ml. In patients with a single treatment, the mean volume was 8.5 ml, and the median volume was 6.95 +/- 4.56 ml (mean +/- standard deviation), with a KTV of up to 15 ml. For prospectively staged radiosurgery, the mean KTV was 28 ml. The marginal radiation dose was 18-22 Gy, with a mean of dose 20 Gy. The mean RBGS score was 1.70. The overall obliteration rate was 91%, including the repeated radiosurgery group (4 patients), in which 100% showed complete obliteration. The overall permanent deficit was 2 of

Target volume geometric change and/or deviation from the cranium during fractionated stereotactic radiotherapy for brain metastases: potential pitfalls in image guidance based on bony anatomy alignment.

PubMed

Ohtakara, Kazuhiro; Hoshi, Hiroaki

2014-12-01

This study sought to evaluate the potential geometrical change and/or displacement of the target relative to the cranium during fractionated stereotactic radiotherapy (FSRT) for treating newly developed brain metastases. For 16 patients with 21 lesions treated with image-guided frameless FSRT in 5 or 10 fractions using a 6-degree-of-freedom image guidance system-integrated platform, the unenhanced computed tomography or T2-weighted magnetic resonance images acquired until the completion of FSRT were fused to the planning image datasets for comparison. Significant change was defined as ≥3-mm change in the tumour diameter or displacement of the tumour centroid. FSRT was started 1 day after planning image acquisition. Tumour shrinkage, deviation and both were observed in 2, 1 and 1 of the 21 lesions, respectively, over a period of 7-13 days. Tumour shrinkage or deviation resulted in an increase or decrease in the marginal dose to the tumour, respectively, and a substantial increase in the irradiated volume for the surrounding tissue irrespective of the pattern of alteration. No obvious differences in the clinical and treatment characteristics were noted among the populations with or without significant changes in tumour volume or position. Target deformity and/or deviation can unexpectedly occur even during relatively short-course FSRT, inevitably leading to a gradual discrepancy between the planned and actually delivered doses to the tumour and surrounding tissue. To appropriately weigh the treatment outcome against the planned dose distribution, target deformity and/or deviation should also be considered in addition to the immobilisation accuracy, as image guidance with bony anatomy alignment does not necessarily guarantee accurate target localisation until completion of FSRT. © 2014 The Royal Australian and New Zealand College of Radiologists.

Target coverage in image-guided stereotactic body radiotherapy of liver tumors.

PubMed

Wunderink, Wouter; Méndez Romero, Alejandra; Vásquez Osorio, Eliana M; de Boer, Hans C J; Brandwijk, René P; Levendag, Peter C; Heijmen, Ben J M

2007-05-01

To determine the effect of image-guided procedures (with computed tomography [CT] and electronic portal images before each treatment fraction) on target coverage in stereotactic body radiotherapy for liver patients using a stereotactic body frame (SBF) and abdominal compression. CT guidance was used to correct for day-to-day variations in the tumor's mean position in the SBF. By retrospectively evaluating 57 treatment sessions, tumor coverage, as obtained with the clinically applied CT-guided protocol, was compared with that of alternative procedures. The internal target volume-plus (ITV(+)) was introduced to explicitly include uncertainties in tumor delineations resulting from CT-imaging artifacts caused by residual respiratory motion. Tumor coverage was defined as the volume overlap of the ITV(+), derived from a tumor delineated in a treatment CT scan, and the planning target volume. Patient stability in the SBF, after acquisition of the treatment CT scan, was evaluated by measuring the displacement of the bony anatomy in the electronic portal images relative to CT. Application of our clinical protocol (with setup corrections following from manual measurements of the distances between the contours of the planning target volume and the daily clinical target volume in three orthogonal planes, multiple two-dimensional) increased the frequency of nearly full (> or = 99%) ITV(+) coverage to 77% compared with 63% without setup correction. An automated three-dimensional method further improved the frequency to 96%. Patient displacements in the SBF were generally small (< or = 2 mm, 1 standard deviation), but large craniocaudal displacements (maximal 7.2 mm) were occasionally observed. Daily, CT-assisted patient setup may substantially improve tumor coverage, especially with the automated three-dimensional procedure. In the present treatment design, patient stability in the SBF should be verified with portal imaging.

SECOND TARGET STATION MODERATOR PERFORMANCE WITH A ROTATING TARGET

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

Remec, Igor; Gallmeier, Franz X; Rennich, Mark J

2016-01-01

Oak Ridge National Laboratory manages and operates the Spallation Neutron Source and the High Flux Isotope Reactor, two of the world's most advanced neutron scattering facilities. Both facilities are funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Science, and are available to researchers from all over the world. Delivering cutting edge science requires continuous improvements and development of the facilities and instruments. The SNS was designed from the outset to accommodate an additional target station, or Second Target Station (STS), and an upgraded accelerator feeding proton beams to STS and the existing First Targetmore » Station (FTS). Upgrade of the accelerator and the design and construction of STS are being proposed. The presently considered STS configuration is driven with short (<1 s) proton pulses at 10 Hz repetition rate and 467 kW proton beam power, and is optimized for high intensity and high resolution long wavelength neutron applications. STS will allow installation of 22 beamlines and will expand and complement the current national neutron scattering capabilities. In 2015 the STS studies were performed for a compact tungsten target; first a stationary tungsten plate target was analyzed to considerable details and then dropped in favor of a rotating target. For both target options the proton beam footprint as small as acceptable from mechanical and heat removal aspects is required to arrive at a compact-volume neutron production zone in the target, which is essential for tight coupling of target and moderators and for achieving high-intensity peak neutron fluxes. This paper will present recent STS work with the emphasis on neutronics and moderator performance.« less

Method and apparatus for producing cryogenic targets

DOEpatents

Murphy, James T.; Miller, John R.

1984-01-01

An improved method and apparatus are given for producing cryogenic inertially driven fusion targets in the fast isothermal freezing (FIF) method. Improved coupling efficiency and greater availability of volume near the target for diagnostic purposes and for fusion driver beam propagation result. Other embodiments include a new electrical switch and a new explosive detonator, all embodiments making use of a purposeful heating by means of optical fibers.

Set-up uncertainties: online correction with X-ray volume imaging.

PubMed

Kataria, Tejinder; Abhishek, Ashu; Chadha, Pranav; Nandigam, Janardhan

2011-01-01

To determine interfractional three-dimensional set-up errors using X-ray volumetric imaging (XVI). Between December 2007 and August 2009, 125 patients were taken up for image-guided radiotherapy using online XVI. After matching of reference and acquired volume view images, set-up errors in three translation directions were recorded and corrected online before treatment each day. Mean displacements, population systematic (Σ), and random (σ) errors were calculated and analyzed using SPSS (v16) software. Optimum clinical target volume (CTV) to planning target volume (PTV) margin was calculated using Van Herk's (2.5Σ + 0.7 σ) and Stroom's (2Σ + 0.7 σ) formula. Patients were grouped in 4 cohorts, namely brain, head and neck, thorax, and abdomen-pelvis. The mean vector displacement recorded were 0.18 cm, 0.15 cm, 0.36 cm, and 0.35 cm for brain, head and neck, thorax, and abdomen-pelvis, respectively. Analysis of individual mean set-up errors revealed good agreement with the proposed 0.3 cm isotropic margins for brain and 0.5 cm isotropic margins for head-neck. Similarly, 0.5 cm circumferential and 1 cm craniocaudal proposed margins were in agreement with thorax and abdomen-pelvic cases. The calculated mean displacements were well within CTV-PTV margin estimates of Van Herk (90% population coverage to minimum 95% prescribed dose) and Stroom (99% target volume coverage by 95% prescribed dose). Employing these individualized margins in a particular cohort ensure comparable target coverage as described in literature, which is further improved if XVI-aided set-up error detection and correction is used before treatment.

Draft Site Treatment Plan (DSTP), Volumes I and II

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

D`Amelio, J.

1994-08-30

Site Treatment Plans (STP) are required for facilities at which the DOE generates or stores mixed waste. This Draft Site Treatment Plan (DSTP) the second step in a three-phase process, identifies the currently preferred options for treating mixed waste at the Savannah River Site (SRS) or for developing treatment technologies where technologies do not exist or need modification. The DSTP reflects site-specific preferred options, developed with the state`s input and based on existing available information. To the extent possible, the DSTP identifies specific treatment facilities for treating the mixed waste and proposes schedules. Where the selection of specific treatment facilitiesmore » is not possible, schedules for alternative activities such as waste characterization and technology assessment are provided. All schedule and cost information presented is preliminary and is subject to change. The DSTP is comprised of two volumes: this Compliance Plan Volume and the Background Volume. This Compliance Plan Volume proposes overall schedules with target dates for achieving compliance with the land disposal restrictions (LDR) of RCRA and procedures for converting the target dates into milestones to be enforced under the Order. The more detailed discussion of the options contained in the Background Volume is provided for informational purposes only.« less

Impact of the introduction of weekly radiotherapy quality assurance meetings at one UK cancer centre

PubMed Central

Brammer, C V; Allerton, R; Churn, M; Joseph, M; Koh, P; Sayers, I; King, M

2014-01-01

Objective: The complexity of radiotherapy planning is increasing rapidly. Delivery and planning is subject to detailed quality assurance (QA) checks. The weakest link is often the oncologists' delineation of the clinical target volume (CTV). Weekly departmental meetings for radiotherapy QA (RTQA) were introduced into the Royal Wolverhampton Hospital, Wolverhampton, UK, in October 2011. This article describes the impact of this on patient care. Methods: CTVs for megavoltage photon radiotherapy courses for all radical, adjuvant and palliative treatments longer than five fractions (with the exception of two field tangential breast treatments not enrolled into clinical trials) were reviewed in the RTQA meeting. Audits were carried out in January 2012 (baseline) and September 2013, each over a 4-week period. Adherence to departmental contouring protocols was assessed and the number of major and minor alterations following peer review were determined. Results: There was no statistically significant difference for major alterations between the two study groups; 8 alterations in 80 patients (10%) for the baseline audit vs 3 alterations from 72 patients (4.2%) in the second audit (p = 0.17). A trend towards a reduction in alterations following peer review was observed. There has, however, been a change in practice resulting in a reduction in variation in CTV definition within our centre and greater adherence to protocols. There is increasing confidence in the quality and constancy of care delivered. Conclusion: Introduction of a weekly QA meeting for target volume definition has facilitated consensus and adoption of departmental clinical guidelines within the unit. Advances in knowledge: The weakest areas in radiotherapy are patient selection and definition of the CTV. Engagement in high-quality RTQA is paramount. This article describes the impact of this in one UK cancer centre. PMID:25251520

SU-E-T-170: Characterization of the Location, Extent, and Proximity to Critical Structures of Target Volumes Provides Detail for Improved Outcome Predictions Among Pancreatic Cancer Patients

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

Cheng, Z; Moore, J; Rosati, L

Purpose: In radiotherapy, size, location and proximity of the target to critical structures influence treatment decisions. It has been shown that proximity of the target predicts dosimetric sparing of critical structures. In addition to dosimetry, precise location of disease has further implications such as tumor invasion, or proximity to major arteries that inhibit surgery. Knowledge of which patients can be converted to surgical candidates by radiation may have high impact on future treat/no-treat decisions. We propose a method to improve our characterization of the location of pancreatic cancer and treatment volume extent with respect to nearby arteries with the goalmore » of developing features to improve clinical predictions and decisions. Methods: Oncospace is a local learning health system that systematically captures clinical outcomes and all aspects of radiotherapy treatment plans, including overlap volume histograms (OVH) – a measure of spatial relationships between two structures. Minimum and maximum distances of PTV and OARs based on OVH, PTV volume, anatomic location by ICD-9 code, and surgical outcome were queried. Normalized distance to center from the left and right kidney was calculated to indicate tumor location and laterality. Distance to critical arteries (celiac, superior mesenteric, common hepatic) is validated by surgical status (borderline resectable, locally advanced converted to resectable). Results: There were 205 pancreas stereotactic body radiotherapy patients treated from 2009–2015 queried. Location/laterality of tumor based on kidney OVH show strong trends between location by OVH and by ICD-9. Compared to the locally advanced group, the borderline resectable group showed larger geometrical distance from critical arteries (p=0.03). Conclusion: Our platform enabled analysis of shape/size-location relationships. These data suggest that PTV volume and attention to distance between PTVs and surrounding OARs and major arteries may be

Radiotherapy treatment planning: benefits of CT-MR image registration and fusion in tumor volume delineation.

PubMed

Djan, Igor; Petrović, Borislava; Erak, Marko; Nikolić, Ivan; Lucić, Silvija

2013-08-01

Development of imaging techniques, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET), made great impact on radiotherapy treatment planning by improving the localization of target volumes. Improved localization allows better local control of tumor volumes, but also minimizes geographical misses. Mutual information is obtained by registration and fusion of images achieved manually or automatically. The aim of this study was to validate the CT-MRI image fusion method and compare delineation obtained by CT versus CT-MRI image fusion. The image fusion software (XIO CMS 4.50.0) was applied to delineate 16 patients. The patients were scanned on CT and MRI in the treatment position within an immobilization device before the initial treatment. The gross tumor volume (GTV) and clinical target volume (CTV) were delineated on CT alone and on CT+MRI images consecutively and image fusion was obtained. Image fusion showed that CTV delineated on a CT image study set is mainly inadequate for treatment planning, in comparison with CTV delineated on CT-MRI fused image study set. Fusion of different modalities enables the most accurate target volume delineation. This study shows that registration and image fusion allows precise target localization in terms of GTV and CTV and local disease control.

Assessment of three-dimensional setup errors in image-guided pelvic radiotherapy for uterine and cervical cancer using kilovoltage cone-beam computed tomography and its effect on planning target volume margins.

PubMed

Patni, Nidhi; Burela, Nagarjuna; Pasricha, Rajesh; Goyal, Jaishree; Soni, Tej Prakash; Kumar, T Senthil; Natarajan, T

2017-01-01

To achieve the best possible therapeutic ratio using high-precision techniques (image-guided radiation therapy/volumetric modulated arc therapy [IGRT/VMAT]) of external beam radiation therapy in cases of carcinoma cervix using kilovoltage cone-beam computed tomography (kV-CBCT). One hundred and five patients of gynecological malignancies who were treated with IGRT (IGRT/VMAT) were included in the study. CBCT was done once a week for intensity-modulated radiation therapy and daily in IGRT/VMAT. These images were registered with the planning CT scan images and translational errors were applied and recorded. In all, 2078 CBCT images were studied. The margins of planning target volume were calculated from the variations in the setup. The setup variation was 5.8, 10.3, and 5.6 mm in anteroposterior, superoinferior, and mediolateral direction. This allowed adequate dose delivery to the clinical target volume and the sparing of organ at risks. Daily kV-CBCT is a satisfactory method of accurate patient positioning in treating gynecological cancers with high-precision techniques. This resulted in avoiding geographic miss.

Agreement Among RTOG Sarcoma Radiation Oncologists in Contouring Suspicious Peritumoral Edema for Preoperative Radiation Therapy of Soft Tissue Sarcoma of the Extremity

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

Bahig, Houda; Roberge, David, E-mail: david.roberge.chum@ssss.gouv.qc.ca; Bosch, Walter

Purpose: Peritumoral edema may harbor sarcoma cells. The extent of suspicious edema (SE) included in the treatment volume is subject to clinical judgment, balancing the risk of missing tumor cells with excess toxicity. Our goal was to determine variability in SE delineation by sarcoma radiation oncologists (RO). Methods and Materials: Twelve expert ROs were provided with T1 gadolinium and T2-weighted MR images of 10 patients with high-grade extremity soft-tissue sarcoma. Gross tumor volume, clinical target volume (CTV)3cm (3 cm longitudinal and 1.5 cm radial margin), and CTV2cm (2 cm longitudinal and 1 cm radial margin) were contoured by a singlemore » observer. Suspicious peritumoral edema, defined as abnormal signal on T2 images, was independently delineated by all 12 ROs. Contouring agreement was analyzed using the simultaneous truth and performance level estimation (STAPLE) algorithm and kappa statistics. Results: The mean volumes of GTV, CTV2cm, and CTV3cm were, respectively, 130 cm{sup 3} (7-413 cm{sup 3}), 280 cm{sup 3} and 360 cm{sup 3}. The mean consensus volume computed using the STAPLE algorithm at 95% confidence interval was 188 cm{sup 3} (24-565 cm{sup 3}) with a substantial overall agreement corrected for chance (mean kappa = 0.71; range: 0.32-0.87). The minimum, maximum, and mean volume of SE (excluding the GTV) were 4, 182, and 58 cm{sup 3} (representing a median of 29% of the GTV volume). The median volume of SE not included in the CTV2cm and in the CTV3cm was 5 and 0.3 cm{sup 3}, respectively. There were 3 large tumors with >30 cm{sup 3} of SE not included in the CTV3cm volume. Conclusion: Despite the fact that SE would empirically seem to be a more subjective volume, a substantial or near-perfect interobserver agreement was observed in SE delineation in most cases with high-grade soft-tissue sarcomas of the extremity. A median of 97% of the consensus SE is within the CTV2cm (99.8% within the CTV3cm). In a minority of cases, however, significant

Agreement among RTOG sarcoma radiation oncologists in contouring suspicious peritumoral edema for preoperative radiation therapy of soft tissue sarcoma of the extremity.

PubMed

Bahig, Houda; Roberge, David; Bosch, Walter; Levin, William; Petersen, Ivy; Haddock, Michael; Freeman, Carolyn; Delaney, Thomas F; Abrams, Ross A; Indelicato, Danny J; Baldini, Elizabeth H; Hitchcock, Ying; Kirsch, David G; Kozak, Kevin R; Wolfson, Aaron; Wang, Dian

2013-06-01

Peritumoral edema may harbor sarcoma cells. The extent of suspicious edema (SE) included in the treatment volume is subject to clinical judgment, balancing the risk of missing tumor cells with excess toxicity. Our goal was to determine variability in SE delineation by sarcoma radiation oncologists (RO). Twelve expert ROs were provided with T1 gadolinium and T2-weighted MR images of 10 patients with high-grade extremity soft-tissue sarcoma. Gross tumor volume, clinical target volume (CTV)3cm (3 cm longitudinal and 1.5 cm radial margin), and CTV2cm (2 cm longitudinal and 1 cm radial margin) were contoured by a single observer. Suspicious peritumoral edema, defined as abnormal signal on T2 images, was independently delineated by all 12 ROs. Contouring agreement was analyzed using the simultaneous truth and performance level estimation (STAPLE) algorithm and kappa statistics. The mean volumes of GTV, CTV2cm, and CTV3cm were, respectively, 130 cm(3) (7-413 cm(3)), 280 cm(3) and 360 cm(3). The mean consensus volume computed using the STAPLE algorithm at 95% confidence interval was 188 cm(3) (24-565 cm(3)) with a substantial overall agreement corrected for chance (mean kappa = 0.71; range: 0.32-0.87). The minimum, maximum, and mean volume of SE (excluding the GTV) were 4, 182, and 58 cm(3) (representing a median of 29% of the GTV volume). The median volume of SE not included in the CTV2cm and in the CTV3cm was 5 and 0.3 cm(3), respectively. There were 3 large tumors with >30 cm(3) of SE not included in the CTV3cm volume. Despite the fact that SE would empirically seem to be a more subjective volume, a substantial or near-perfect interobserver agreement was observed in SE delineation in most cases with high-grade soft-tissue sarcomas of the extremity. A median of 97% of the consensus SE is within the CTV2cm (99.8% within the CTV3cm). In a minority of cases, however, significant expansion of the CTVs is required to cover SE. Copyright © 2013 Elsevier Inc. All rights

Sci-Thur PM – Brachytherapy 03: Identifying the impact of seroma visualization on permanent breast seed implant brachytherapy

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

Morton, Daniel; Batchelar, Deidre; Hilts, Michelle

Purpose: Uncertainties in target identification can reduce treatment accuracy in permanent breast seed implant (PBSI) brachytherapy. This study evaluates the relationship between seroma visualization and seed placement accuracy. Methods: Spatially co-registered CT and 3D ultrasound (US) images were acquired for 10 patients receiving PBSI. Seromas were retrospectively contoured independently by 3 radiation oncologists on both CT and US and respective consensus volumes were defined, CTV{sub CT} and CTV{sub US}. The seroma clarity and inter-user conformity index (CI), as well as inter-modality CI, volume, and positional differences were evaluated. Correlations with seed placement accuracy were then assessed. CTVs were expanded bymore » 1.25cm to create PTV{sub CT} and PTV{sub US} and evaluate the conformity with PTV{sub Clinical} (CTV{sub Clinical}+1.25cm) used in treatment planning. The change in PTV coincidence by expanding PTV{sub Clinical} by 0.25cm was determined. Results: CTV{sub US} were a mean 68 ± 12% smaller than CTV{sub CT} and generally had improved clarity and inter-user conformity. No correlations between seed displacement and CTV{sub US}-CTV{sub CT} positional difference or CI were observed. Greater seed displacements were associated with larger CTV{sub US}-CTV{sub CT} volume differences (r=−0.65) and inter-user CT CI (r=−0.74). A median (range) 88% (71–99%) of PTV{sub CT} and 83% (69–100%) of PTV{sub US} were contained within PTV{sub Clinical}. Expanding treatment margins to 1.5cm increased coincidence to 98% (86–100%) and 94% (82–100%), respectively. Conclusions: Differences in seroma visualization impacts seed displacement in PBSI. Reducing dependence on CT by incorporating 3DUS into target identification, or expanding CT-based treatment margins to 1.5cm may reduce or mitigate uncertainties related to seroma visualization.« less

SU-E-J-192: Verification of 4D-MRI Internal Target Volume Using Cine MRI

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

Lafata, K; Czito, B; Palta, M

Purpose: To investigate the accuracy of 4D-MRI in determining the Internal Target Volume (ITV) used in radiation oncology treatment planning of liver cancers. Cine MRI is used as the standard baseline in establishing the feasibility and accuracy of 4D-MRI tumor motion within the liver. Methods: IRB approval was obtained for this retrospective study. Analysis was performed on MR images from four patients receiving external beam radiation therapy for liver cancer at our institution. Eligible patients received both Cine and 4D-MRI scans before treatment. Cine images were acquired sagittally in real time at a slice bisecting the tumor, while 4D imagesmore » were acquired volumetrically. Cine MR DICOM headers were manipulated such that each respiratory frame was assigned a unique slice location. This approach permitted the treatment planning system (Eclipse, Varian Medical Systems) to recognize a complete respiratory cycle as a “volume”, where the gross tumor was contoured temporally. Software was developed to calculate the union of all frame contours in the structure set, resulting in the corresponding plane of the ITV projecting through the middle of the tumor, defined as the Internal Target Area (ITA). This was repeated for 4D-MRI, at the corresponding slice location, allowing a direct comparison of ITAs obtained from each modality. Results: Four patients have been analyzed. ITAs contoured from 4D-MRI correlate with contours from Cine MRI. The mean error of 4D values relative to Cine values is 7.67 +/− 2.55 %. No single ITA contoured from 4D-MRI demonstrated more than 10.5 % error compared to its Cine MRI counterpart. Conclusion: Motion management is a significant aspect of treatment planning within dynamic environments such as the liver, where diaphragmatic and cardiac activity influence plan accuracy. This small pilot study suggests that 4D-MRI based ITA measurements agree with Cine MRI based measurements, an important step towards clinical implementation

Method and apparatus for producing cryogenic targets

DOEpatents

Murphy, J.T.; Miller, J.R.

1984-08-07

An improved method and apparatus are given for producing cryogenic inertially driven fusion targets in the fast isothermal freezing (FIF) method. Improved coupling efficiency and greater availability of volume near the target for diagnostic purposes and for fusion driver beam propagation result. Other embodiments include a new electrical switch and a new explosive detonator, all embodiments making use of a purposeful heating by means of optical fibers. 6 figs.

Thinkers on Education. Volume 2.

ERIC Educational Resources Information Center

Morsy, Zaghloul, Ed.

This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the second volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

Thinkers on Education. Volume 1.

ERIC Educational Resources Information Center

Morsy, Zaghloul, Ed.

This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the first volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

Thinkers on Education. Volume 4.

ERIC Educational Resources Information Center

Morsy, Zaghloul, Ed.

This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the fourth volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

What Is the Optimal Target Convective Volume in On-Line Hemodiafiltration Therapy?

PubMed

Canaud, Bernard; Koehler, Katrin; Bowry, Sudhir; Stuard, Stefano

2017-01-01

Conventional diffusion-based dialysis modalities including high-flux hemodialysis are limited in their capacity to effectively remove large uremic toxins and to improve outcomes for end-stage chronic kidney disease (ESKD) patients. By increasing convective solute transport, hemodiafiltration (HDF) enhances solute removal capacity over a broad range of middle- and large-size uremic toxins implicated in the pathophysiology of chronic kidney disease. Furthermore, by offering flexible convection volume, on-line HDF permits customizing the treatment dose to the patient's needs. In addition, convective-based modalities have been shown to improve hemodynamic stability and to reduce patients' inflammation profile - both of which are implicated in CKD morbidity and mortality. Growing clinical evidence indicates that HDF-based modalities provide ESKD patients with a number of clinical and biological benefits, including improved outcomes. Interestingly, it has recently emerged that the clinical benefits associated with HDF are positively associated with the total ultrafiltered volume per session (and per week), namely convective dose. In this chapter, we revisit the concept of convective dose and discuss the threshold value above which an improvement in ESKD patient outcome can be expected. This particular point will be addressed by stratifying the level of efficacy of convective volumes, schematically defined as minimal, optimal, personalized, and maximal. In addition, factors and best clinical practices implicated in the achievement of an optimal convective dose are reviewed. To conclude, we show how HDF differs from standard hemodialysis and why HDF offers a paradigm shift in renal replacement therapy. © 2017 S. Karger AG, Basel.

High-Grade Glioma Radiation Therapy Target Volumes and Patterns of Failure Obtained From Magnetic Resonance Imaging and {sup 18}F-FDOPA Positron Emission Tomography Delineations From Multiple Observers

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

Kosztyla, Robert, E-mail: rkosztyla@bccancer.bc.ca; Chan, Elisa K.; Hsu, Fred

Purpose: The objective of this study was to compare recurrent tumor locations after radiation therapy with pretreatment delineations of high-grade gliomas from magnetic resonance imaging (MRI) and 3,4-dihydroxy-6-[{sup 18}F]fluoro-L-phenylalanine ({sup 18}F-FDOPA) positron emission tomography (PET) using contours delineated by multiple observers. Methods and Materials: Nineteen patients with newly diagnosed high-grade gliomas underwent computed tomography (CT), gadolinium contrast-enhanced MRI, and {sup 18}F-FDOPA PET/CT. The image sets (CT, MRI, and PET/CT) were registered, and 5 observers contoured gross tumor volumes (GTVs) using MRI and PET. Consensus contours were obtained by simultaneous truth and performance level estimation (STAPLE). Interobserver variability was quantified bymore » the percentage of volume overlap. Recurrent tumor locations after radiation therapy were contoured by each observer using CT or MRI. Consensus recurrence contours were obtained with STAPLE. Results: The mean interobserver volume overlap for PET GTVs (42% ± 22%) and MRI GTVs (41% ± 22%) was not significantly different (P=.67). The mean consensus volume was significantly larger for PET GTVs (58.6 ± 52.4 cm{sup 3}) than for MRI GTVs (30.8 ± 26.0 cm{sup 3}, P=.003). More than 95% of the consensus recurrence volume was within the 95% isodose surface for 11 of 12 (92%) cases with recurrent tumor imaging. Ten (91%) of these cases extended beyond the PET GTV, and 9 (82%) were contained within a 2-cm margin on the MRI GTV. One recurrence (8%) was located outside the 95% isodose surface. Conclusions: High-grade glioma contours obtained with {sup 18}F-FDOPA PET had similar interobserver agreement to volumes obtained with MRI. Although PET-based consensus target volumes were larger than MRI-based volumes, treatment planning using PET-based volumes may not have yielded better treatment outcomes, given that all but 1 recurrence extended beyond the PET GTV and most were contained by a 2

Quantitative targeting maps based on experimental investigations for a branched tube model in magnetic drug targeting

NASA Astrophysics Data System (ADS)

Gitter, K.; Odenbach, S.

2011-12-01

Magnetic drug targeting (MDT), because of its high targeting efficiency, is a promising approach for tumour treatment. Unwanted side effects are considerably reduced, since the nanoparticles are concentrated within the target region due to the influence of a magnetic field. Nevertheless, understanding the transport phenomena of nanoparticles in an artery system is still challenging. This work presents experimental results for a branched tube model. Quantitative results describe, for example, the net amount of nanoparticles that are targeted towards the chosen region due to the influence of a magnetic field. As a result of measurements, novel drug targeting maps, combining, e.g. the magnetic volume force, the position of the magnet and the net amount of targeted nanoparticles, are presented. The targeting maps are valuable for evaluation and comparison of setups and are also helpful for the design and the optimisation of a magnet system with an appropriate strength and distribution of the field gradient. The maps indicate the danger of accretion within the tube and also show the promising result of magnetic drug targeting that up to 97% of the nanoparticles were successfully targeted.

Impact of 4D image quality on the accuracy of target definition.

PubMed

Nielsen, Tine Bjørn; Hansen, Christian Rønn; Westberg, Jonas; Hansen, Olfred; Brink, Carsten

2016-03-01

Delineation accuracy of target shape and position depends on the image quality. This study investigates whether the image quality on standard 4D systems has an influence comparable to the overall delineation uncertainty. A moving lung target was imaged using a dynamic thorax phantom on three different 4D computed tomography (CT) systems and a 4D cone beam CT (CBCT) system using pre-defined clinical scanning protocols. Peak-to-peak motion and target volume were registered using rigid registration and automatic delineation, respectively. A spatial distribution of the imaging uncertainty was calculated as the distance deviation between the imaged target and the true target shape. The measured motions were smaller than actual motions. There were volume differences of the imaged target between respiration phases. Imaging uncertainties of >0.4 cm were measured in the motion direction which showed that there was a large distortion of the imaged target shape. Imaging uncertainties of standard 4D systems are of similar size as typical GTV-CTV expansions (0.5-1 cm) and contribute considerably to the target definition uncertainty. Optimising and validating 4D systems is recommended in order to obtain the most optimal imaged target shape.

Technology transfer from NASA to targeted industries, volume 1

NASA Technical Reports Server (NTRS)

Mccain, Wayne; Schroer, Bernard J.; Souder, William E.; Spann, Mary S.; Watters, Harry; Ziemke, M. Carl

1993-01-01

This report summarizes the University of Alabama in Huntsville (UAH) technology transfer to three target industries with focus on the apparel manufacturing industry in Alabama. Also included in this report are an analysis of the 1992 problem statements submitted by Alabama firms, the results of the survey of 1987-88 NASA Tech Brief requests, the results of the followup to Alabama submitted problem statements, and the development of the model describing the MSFC technology transfer process.

Factors influencing the difference between forecasted and actual drug sales volumes under the price-volume agreement in South Korea.

PubMed

Park, Sun-Young; Han, Euna; Kim, Jini; Lee, Eui-Kyung

2016-08-01

This study analyzed factors contributing to increases in the actual sales volumes relative to forecasted volumes of drugs under price-volume agreement (PVA) policy in South Korea. Sales volumes of newly listed drugs on the national formulary are monitored under PVA policy. When actual sales volume exceeds the pre-agreed forecasted volume by 30% or more, the drug is subject to price-reduction. Logistic regression assessed the factors related to whether drugs were the PVA price-reduction drugs. A generalized linear model with gamma distribution and log-link assessed the factors influencing the increase in actual volumes compared to forecasted volume in the PVA price-reduction drugs. Of 186 PVA monitored drugs, 34.9% were price-reduction drugs. Drugs marketed by pharmaceutical companies with previous-occupation in the therapeutic markets were more likely to be PVA price-reduction drugs than drugs marketed by firms with no previous-occupation. Drugs of multinational pharmaceutical companies were more likely to be PVA price-reduction drugs than those of domestic companies. Having more alternative existing drugs was significantly associated with higher odds of being PVA price-reduction drugs. Among the PVA price-reduction drugs, the increasing rate of actual volume compared to forecasted volume was significantly higher in drugs with clinical usefulness. By focusing the negotiation efforts on those target drugs, PVA policy can be administered more efficiently with the improved predictability of the drug sales volumes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Proposed definition of the vaginal cuff and paracolpium clinical target volume in postoperative uterine cervical cancer.

PubMed

Murakami, Naoya; Norihisa, Yoshiki; Isohashi, Fumiaki; Murofushi, Keiko; Ariga, Takuro; Kato, Tomoyasu; Inaba, Koji; Okamoto, Hiroyuki; Ito, Yoshinori; Toita, Takafumi; Itami, Jun

2016-01-01

The aim of this study was to develop an appropriate definition for vaginal cuff and paracolpium clinical target volume (CTV) for postoperative intensity modulated radiation therapy in patients with uterine cervical cancer. A working subgroup was organized within the Radiation Therapy Study Group of the Japan Clinical Oncology Group to develop a definition for the postoperative vaginal cuff and paracolpium CTV in December 2013. The group consisted of 5 radiation oncologists who specialized in gynecologic oncology and a gynecologic oncologist. A comprehensive literature review that included anatomy, surgery, and imaging fields was performed and was followed by multiple discreet face-to-face discussions and e-mail messages before a final consensus was reached. Definitions for the landmark structures in all directions that demarcate the vaginal cuff and paracolpium CTV were decided by consensus agreement of the working group. A table was created that showed boundary structures of the vaginal cuff and paracolpium CTV in each direction. A definition of the postoperative cervical cancer vaginal cuff and paracolpium CTV was developed. It is expected that this definition guideline will serve as a template for future radiation therapy clinical trial protocols, especially protocols involving intensity modulated radiation therapy. Copyright © 2016 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

Limitations of the planning organ at risk volume (PRV) concept.

PubMed

Stroom, Joep C; Heijmen, Ben J M

2006-09-01

Previously, we determined a planning target volume (PTV) margin recipe for geometrical errors in radiotherapy equal to M(T) = 2 Sigma + 0.7 sigma, with Sigma and sigma standard deviations describing systematic and random errors, respectively. In this paper, we investigated margins for organs at risk (OAR), yielding the so-called planning organ at risk volume (PRV). For critical organs with a maximum dose (D(max)) constraint, we calculated margins such that D(max) in the PRV is equal to the motion averaged D(max) in the (moving) clinical target volume (CTV). We studied margins for the spinal cord in 10 head-and-neck cases and 10 lung cases, each with two different clinical plans. For critical organs with a dose-volume constraint, we also investigated whether a margin recipe was feasible. For the 20 spinal cords considered, the average margin recipe found was: M(R) = 1.6 Sigma + 0.2 sigma with variations for systematic and random errors of 1.2 Sigma to 1.8 Sigma and -0.2 sigma to 0.6 sigma, respectively. The variations were due to differences in shape and position of the dose distributions with respect to the cords. The recipe also depended significantly on the volume definition of D(max). For critical organs with a dose-volume constraint, the PRV concept appears even less useful because a margin around, e.g., the rectum changes the volume in such a manner that dose-volume constraints stop making sense. The concept of PRV for planning of radiotherapy is of limited use. Therefore, alternative ways should be developed to include geometric uncertainties of OARs in radiotherapy planning.

Youth Attitude Tracking Study. Volume 1. Spring 1980.

DTIC Science & Technology

1980-08-01

JobICharacteristics 11 Active Duty Positive Propensity Respondents Target Market Profile 13 Advertising Awareness 14 ’LIAttitudes Toward Enlistment Incentives...service advertising awareness. The fact that target market men value job characteristics that pertain to improving oneself suggests that this change in copy...W,0-R143 ii4 YOUTH ATTITUDE TRACKING STUDY VOLUME i SPRING i988(U) 1/3 MARKET FACTS INC CHICAGO IL PUBLIC SECTOR RESEARCH CORP J T HEISLER AUG 80

Atlas-Based Segmentation Improves Consistency and Decreases Time Required for Contouring Postoperative Endometrial Cancer Nodal Volumes

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

Young, Amy V.; Department of Radiation Oncology, St. Luke's-Roosevelt Hospital, New York, NY; Wortham, Angela

2011-03-01

Purpose: Accurate target delineation of the nodal volumes is essential for three-dimensional conformal and intensity-modulated radiotherapy planning for endometrial cancer adjuvant therapy. We hypothesized that atlas-based segmentation ('autocontouring') would lead to time savings and more consistent contours among physicians. Methods and Materials: A reference anatomy atlas was constructed using the data from 15 postoperative endometrial cancer patients by contouring the pelvic nodal clinical target volume on the simulation computed tomography scan according to the Radiation Therapy Oncology Group 0418 trial using commercially available software. On the simulation computed tomography scans from 10 additional endometrial cancer patients, the nodal clinical targetmore » volume autocontours were generated. Three radiation oncologists corrected the autocontours and delineated the manual nodal contours under timed conditions while unaware of the other contours. The time difference was determined, and the overlap of the contours was calculated using Dice's coefficient. Results: For all physicians, manual contouring of the pelvic nodal target volumes and editing the autocontours required a mean {+-} standard deviation of 32 {+-} 9 vs. 23 {+-} 7 minutes, respectively (p = .000001), a 26% time savings. For each physician, the time required to delineate the manual contours vs. correcting the autocontours was 30 {+-} 3 vs. 21 {+-} 5 min (p = .003), 39 {+-} 12 vs. 30 {+-} 5 min (p = .055), and 29 {+-} 5 vs. 20 {+-} 5 min (p = .0002). The mean overlap increased from manual contouring (0.77) to correcting the autocontours (0.79; p = .038). Conclusion: The results of our study have shown that autocontouring leads to increased consistency and time savings when contouring the nodal target volumes for adjuvant treatment of endometrial cancer, although the autocontours still required careful editing to ensure that the lymph nodes at risk of recurrence are properly included in the

Defining the "Hostile Pelvis" for Intensity Modulated Radiation Therapy: The Impact of Anatomic Variations in Pelvic Dimensions on Dose Delivered to Target Volumes and Organs at Risk in Patients With High-Risk Prostate Cancer Treated With Whole Pelvic Radiation Therapy.

PubMed

Yirmibeşoğlu Erkal, Eda; Karabey, Sinan; Karabey, Ayşegül; Hayran, Mutlu; Erkal, Haldun Şükrü

2015-07-15

The aim of this study was to evaluate the impact of variations in pelvic dimensions on the dose delivered to the target volumes and the organs at risk (OARs) in patients with high-risk prostate cancer (PCa) to be treated with whole pelvic radiation therapy (WPRT) in an attempt to define the hostile pelvis in terms of intensity modulated radiation therapy (IMRT). In 45 men with high-risk PCa to be treated with WPRT, the target volumes and the OARs were delineated, the dose constraints for the OARs were defined, and treatment plans were generated according to the Radiation Therapy Oncology Group 0924 protocol. Six dimensions to reflect the depth, width, and height of the bony pelvis were measured, and 2 indexes were calculated from the planning computed tomographic scans. The minimum dose (Dmin), maximum dose (Dmax), and mean dose (Dmean) for the target volumes and OARs and the partial volumes of each of these structures receiving a specified dose (VD) were calculated from the dose-volume histograms (DVHs). The data from the DVHs were correlated with the pelvic dimensions and indexes. According to an overall hostility score (OHS) calculation, 25 patients were grouped as having a hospitable pelvis and 20 as having a hostile pelvis. Regarding the OHS grouping, the DVHs for the bladder, bowel bag, left femoral head, and right femoral head differed in favor of the hospitable pelvis group, and the DVHs for the rectum differed for a range of lower doses in favor of the hospitable pelvis group. Pelvimetry might be used as a guide to define the challenging anatomy or the hostile pelvis in terms of treatment planning for IMRT in patients with high-risk PCa to be treated with WPRT. Copyright © 2015 Elsevier Inc. All rights reserved.

Defining the “Hostile Pelvis” for Intensity Modulated Radiation Therapy: The Impact of Anatomic Variations in Pelvic Dimensions on Dose Delivered to Target Volumes and Organs at Risk in Patients With High-Risk Prostate Cancer Treated With Whole Pelvic Radiation Therapy

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

Yirmibeşoğlu Erkal, Eda, E-mail: eyirmibesoglu@yahoo.com; Karabey, Sinan; Karabey, Ayşegül

2015-07-15

Purpose: The aim of this study was to evaluate the impact of variations in pelvic dimensions on the dose delivered to the target volumes and the organs at risk (OARs) in patients with high-risk prostate cancer (PCa) to be treated with whole pelvic radiation therapy (WPRT) in an attempt to define the hostile pelvis in terms of intensity modulated radiation therapy (IMRT). Methods and Materials: In 45 men with high-risk PCa to be treated with WPRT, the target volumes and the OARs were delineated, the dose constraints for the OARs were defined, and treatment plans were generated according to themore » Radiation Therapy Oncology Group 0924 protocol. Six dimensions to reflect the depth, width, and height of the bony pelvis were measured, and 2 indexes were calculated from the planning computed tomographic scans. The minimum dose (D{sub min}), maximum dose (D{sub max}), and mean dose (D{sub mean}) for the target volumes and OARs and the partial volumes of each of these structures receiving a specified dose (V{sub D}) were calculated from the dose-volume histograms (DVHs). The data from the DVHs were correlated with the pelvic dimensions and indexes. Results: According to an overall hostility score (OHS) calculation, 25 patients were grouped as having a hospitable pelvis and 20 as having a hostile pelvis. Regarding the OHS grouping, the DVHs for the bladder, bowel bag, left femoral head, and right femoral head differed in favor of the hospitable pelvis group, and the DVHs for the rectum differed for a range of lower doses in favor of the hospitable pelvis group. Conclusions: Pelvimetry might be used as a guide to define the challenging anatomy or the hostile pelvis in terms of treatment planning for IMRT in patients with high-risk PCa to be treated with WPRT.« less

Laser Irradiated Foam Targets: Absorption and Radiative Properties

NASA Astrophysics Data System (ADS)

Salvadori, Martina; Luigi Andreoli, Pier; Cipriani, Mattia; Consoli, Fabrizio; Cristofari, Giuseppe; De Angelis, Riccardo; di Giorgio, Giorgio; Giulietti, Danilo; Ingenito, Francesco; Gus'kov, Sergey Yu.; Rupasov, Alexander A.

2018-01-01

An experimental campaign to characterize the laser radiation absorption of foam targets and the subsequent emission of radiation from the produced plasma was carried out in the ABC facility of the ENEA Research Center in Frascati (Rome). Different targets have been used: plastic in solid or foam state and aluminum targets. The activated different diagnostics allowed to evaluate the plasma temperature, the density distribution, the fast particle spectrum and the yield of the X-Ray radiation emitted by the plasma for the different targets. These results confirm the foam homogenization action on laser-plasma interaction, mainly attributable to the volume absorption of the laser radiation propagating in such structured materials. These results were compared with simulation absorption models of the laser propagating into a foam target.

Target motion tracking in MRI-guided transrectal robotic prostate biopsy.

PubMed

Tadayyon, Hadi; Lasso, Andras; Kaushal, Aradhana; Guion, Peter; Fichtinger, Gabor

2011-11-01

MRI-guided prostate needle biopsy requires compensation for organ motion between target planning and needle placement. Two questions are studied and answered in this paper: 1) is rigid registration sufficient in tracking the targets with an error smaller than the clinically significant size of prostate cancer and 2) what is the effect of the number of intraoperative slices on registration accuracy and speed? we propose multislice-to-volume registration algorithms for tracking the biopsy targets within the prostate. Three orthogonal plus additional transverse intraoperative slices are acquired in the approximate center of the prostate and registered with a high-resolution target planning volume. Both rigid and deformable scenarios were implemented. Both simulated and clinical MRI-guided robotic prostate biopsy data were used to assess tracking accuracy. average registration errors in clinical patient data were 2.6 mm for the rigid algorithm and 2.1 mm for the deformable algorithm. rigid tracking appears to be promising. Three tracking slices yield significantly high registration speed with an affordable error.

A comparative study of the target volume definition in radiotherapy with «Slow CT Scan» vs. 4D PET/CT Scan in early stages non-small cell lung cancer.

PubMed

Molla, M; Anducas, N; Simó, M; Seoane, A; Ramos, M; Cuberas-Borros, G; Beltran, M; Castell, J; Giralt, J

To evaluate the use of 4D PET/CT to quantify tumor respiratory motion compared to the «Slow»-CT (CTs) in the radiotherapy planning process. A total of 25 patients with inoperable early stage non small cell lung cancer (NSCLC) were included in the study. Each patient was imaged with a CTs (4s/slice) and 4D PET/CT. The adequacy of each technique for respiratory motion capture was evaluated using the volume definition for each of the following: Internal target volume (ITV) 4D and ITVslow in relation with the volume defined by the encompassing volume of 4D PET/CT and CTs (ITVtotal). The maximum distance between the edges of the volume defined by each technique to that of the total volume was measured in orthogonal beam's eye view. The ITV4D showed less differences in relation with the ITVtotal in both the cranio-caudal and the antero-posterior axis compared to the ITVslow. The maximum differences were 0.36mm in 4D PET/CTand 0.57mm in CTs in the antero-posterior axis. 4D PET/CT resulted in the definition of more accurate (ITV4D/ITVtotal 0.78 vs. ITVs/ITVtotal 0.63), and larger ITVs (19.9 cc vs. 16.3 cc) than those obtained with CTs. Planning with 4D PET/CT in comparison with CTs, allows incorporating tumor respiratory motion and improving planning radiotherapy of patients in early stages of lung cancer. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

A scaling relationship for impact-induced melt volume

NASA Astrophysics Data System (ADS)

Nakajima, M.; Rubie, D. C.; Melosh, H., IV; Jacobson, S. A.; Golabek, G.; Nimmo, F.; Morbidelli, A.

2016-12-01

During the late stages of planetary accretion, protoplanets experience a number of giant impacts and extensive mantle melting. The impactor's core sinks through the molten part of the target mantle (magma ocean) and experiences metal-silicate partitioning (e.g., Stevenson, 1990). For understanding the chemical evolution of the planetary mantle and core, we need to determine the impact-induced melt volume because the partitioning strongly depends on the ranges of the pressures and temperatures within the magma ocean. Previous studies have investigated the effects of small impacts (i.e. impact cratering) on melt volume, but those for giant impacts are not well understood yet. Here, we perform giant impact simulations to derive a scaling law for melt volume as a function of impact velocity, impact angle, and impactor-to-target mass ratio. We use two different numerical codes, namely smoothed particle hydrodynamics we developed (SPH, a particle method) and the code iSALE (a grid-based method) to compare their outcomes. Our simulations show that these two codes generally agree as long as the same equation of state is used. We also find that some of the previous studies developed for small impacts (e.g., Abramov et al., 2012) overestimate giant impact melt volume by orders of magnitudes partly because these models do not consider self-gravity of the impacting bodies. Therefore, these models may not be extrapolated to large impacts. Our simulations also show that melt volume can be scaled by the total mass of the system. In this presentation, we further discuss geochemical implications for giant impacts on planets, including Earth and Mars.

The ADVANCE project : formal evaluation of the targeted deployment. Volume 2

DOT National Transportation Integrated Search

1997-01-01

This document reports on the formal evaluation of the targeted (limited but highly focused) deployment of the Advanced Driver and Vehicle Advisory Navigation ConcEpt (ADVANCE), an in-vehicle advanced traveler information system designed to provide sh...

A new brain positron emission tomography scanner with semiconductor detectors for target volume delineation and radiotherapy treatment planning in patients with nasopharyngeal carcinoma.

PubMed

Katoh, Norio; Yasuda, Koichi; Shiga, Tohru; Hasegawa, Masakazu; Onimaru, Rikiya; Shimizu, Shinichi; Bengua, Gerard; Ishikawa, Masayori; Tamaki, Nagara; Shirato, Hiroki

2012-03-15

We compared two treatment planning methods for stereotactic boost for treating nasopharyngeal carcinoma (NPC): the use of conventional whole-body bismuth germanate (BGO) scintillator positron emission tomography (PET(CONV)WB) versus the new brain (BR) PET system using semiconductor detectors (PET(NEW)BR). Twelve patients with NPC were enrolled in this study. [(18)F]Fluorodeoxyglucose-PET images were acquired using both the PET(NEW)BR and the PET(CONV)WB system on the same day. Computed tomography (CT) and two PET data sets were transferred to a treatment planning system, and the PET(CONV)WB and PET(NEW)BR images were coregistered with the same set of CT images. Window width and level values for all PET images were fixed at 3000 and 300, respectively. The gross tumor volume (GTV) was visually delineated on PET images by using either PET(CONV)WB (GTV(CONV)) images or PET(NEW)BR (GTV(NEW)) images. Assuming a stereotactic radiotherapy boost of 7 ports, the prescribed dose delivered to 95% of the planning target volume (PTV) was set to 2000 cGy in 4 fractions. The average absolute volume (±standard deviation [SD]) of GTV(NEW) was 15.7 ml (±9.9) ml, and that of GTV(CONV) was 34.0 (±20.5) ml. The average GTV(NEW) was significantly smaller than that of GTV(CONV) (p = 0.0006). There was no statistically significant difference between the maximum dose (p = 0.0585) and the mean dose (p = 0.2748) of PTV. The radiotherapy treatment plan based on the new gross tumor volume (PLAN(NEW)) significantly reduced maximum doses to the cerebrum and cerebellum (p = 0.0418) and to brain stem (p = 0.0041). Results of the present study suggest that the new brain PET system using semiconductor detectors can provide more accurate tumor delineation than the conventional whole-body BGO PET system and may be an important tool for functional and molecular radiotherapy treatment planning. Copyright © 2012 Elsevier Inc. All rights reserved.

Impact of FDG-PET on radiation therapy volume delineation in non-small-cell lung cancer.

PubMed

Bradley, Jeffrey; Thorstad, Wade L; Mutic, Sasa; Miller, Tom R; Dehdashti, Farrokh; Siegel, Barry A; Bosch, Walter; Bertrand, Rudi J

2004-05-01

Locoregional failure remains a significant problem for patients receiving definitive radiation therapy alone or combined with chemotherapy for non-small-cell lung cancer (NSCLC). Positron emission tomography (PET) with [(18)F]fluoro-2-deoxy-d-glucose (FDG) has proven to be a valuable diagnostic and staging tool for NSCLC. This prospective study was performed to determine the impact of treatment simulation with FDG-PET and CT on radiation therapy target volume definition and toxicity profiles by comparison to simulation with computed tomography (CT) scanning alone. Twenty-six patients with Stages I-III NSCLC were studied. Each patient underwent sequential CT and FDG-PET simulation on the same day. Immobilization devices used for both simulations included an alpha cradle, a flat tabletop, 6 external fiducial markers, and a laser positioning system. A radiation therapist participated in both simulations to reproduce the treatment setup. Both the CT and fused PET/CT image data sets were transferred to the radiation treatment planning workstation for contouring. Each FDG-PET study was reviewed with the interpreting nuclear radiologist before tumor volumes were contoured. The fused PET/CT images were used to develop the three-dimensional conformal radiation therapy (3DCRT) plan. A second physician, blinded to the results of PET, contoured the gross tumor volumes (GTV) and planning target volumes (PTV) from the CT data sets, and these volumes were used to generate mock 3DCRT plans. The PTV was defined by a 10-mm margin around the GTV. The two 3DCRT plans for each patient were compared with respect to the GTV, PTV, mean lung dose, volume of normal lung receiving > or =20 Gy (V20), and mean esophageal dose. The FDG-PET findings altered the AJCC TNM stage in 8 of 26 (31%) patients; 2 patients were diagnosed with metastatic disease based on FDG-PET and received palliative radiation therapy. Of the 24 patients who were planned with 3DCRT, PET clearly altered the radiation

Time to achieve target mean arterial pressure during resuscitation from experimental anaphylactic shock in an animal model. A comparison of adrenaline alone or in combination with different volume expanders.

PubMed

Tajima, K; Zheng, F; Collange, O; Barthel, G; Thornton, S N; Longrois, D; Levy, B; Audibert, G; Malinovsky, J M; Mertes, P M

2013-11-01

Anaphylactic shock is a rare, but potentially lethal complication, combining life-threatening circulatory failure and massive fluid shifts. Treatment guidelines rely on adrenaline and volume expansion by intravenous fluids, but there is no solid evidence for the choice of one specific type of fluid over another. Our purpose was to compare the time to achieve target mean arterial pressure upon resuscitation using adrenaline alone versus adrenaline with different resuscitation fluids in an animal model and to compare the tissue oxygen pressures (PtiO2) with the various strategies. Twenty-five ovalbumin-sensitised Brown Norway rats were allocated to five groups after anaphylactic shock induction: vehicle (CON), adrenaline alone (AD), or adrenaline with isotonic saline (AD+IS), hydroxyethyl starch (AD+HES) or hypertonic saline (AD+HS). Time to reach a target mean arterial pressure value of 75 mmHg, cardiac output, skeletal muscle PtiO2, lactate/pyruvate ratio and cumulative doses of adrenaline were recorded. Non-treated rats died within 15 minutes. The target mean arterial pressure value was reached faster with AD+HES (median: 10 minutes, range: 7.5 to 12.5 minutes) and AD+IS (median: 17.5 minutes, range: 5 to 25 minutes) versus adrenaline alone (median: 25 minutes, range: 20-30 minutes). There were also reduced adrenaline requirements in these groups. The skeletal muscle PtiO2 was restored only in the AD+HES group. Although direct extrapolation to humans should be made with caution, our results support the combined use of adrenaline and volume expansion for resuscitation from anaphylactic shock. When used with adrenaline the most effective fluid was hydroxyethyl starch, whereas hypertonic saline was the least effective.

Dynamic magnetic resonance imaging assessment of vascular targeting agent effects in rat intracerebral tumor models

PubMed Central

Muldoon, Leslie L.; Gahramanov, Seymur; Li, Xin; Marshall, Deborah J.; Kraemer, Dale F.; Neuwelt, Edward A.

2011-01-01

We used dynamic MRI to evaluate the effects of monoclonal antibodies targeting brain tumor vasculature. Female athymic rats with intracerebral human tumor xenografts were untreated or treated with intetumumab, targeting αV-integrins, or bevacizumab, targeting vascular endothelial growth factor (n = 4–6 per group). Prior to treatment and at 1, 3, and 7 days after treatment, we performed standard MRI to assess tumor volume, dynamic susceptibility-contrast MRI with the blood-pool iron oxide nanoparticle ferumoxytol to evaluate relative cerebral blood volume (rCBV), and dynamic contrast-enhanced MRI to assess tumor vascular permeability. Tumor rCBV increased by 27 ± 13% over 7 days in untreated rats; intetumumab increased tumor rCBV by 65 ± 10%, whereas bevacizumab reduced tumor rCBV by 31 ± 10% at 7 days (P < .001 for group and day). Similarly, intetumumab increased brain tumor vascular permeability compared with controls at 3 and 7 days after treatment, whereas bevacizumab decreased tumor permeability within 24 hours (P = .0004 for group, P = .0081 for day). All tumors grew over the 7-day assessment period, but bevacizumab slowed the increase in tumor volume on MRI. We conclude that the vascular targeting agents intetumumab and bevacizumab had diametrically opposite effects on dynamic MRI of tumor vasculature in rat brain tumor models. Targeting αV-integrins increased tumor vascular permeability and blood volume, whereas bevacizumab decreased both measures. These findings have implications for chemotherapy delivery and antitumor efficacy. PMID:21123368

Predicting Nonauditory Adverse Radiation Effects Following Radiosurgery for Vestibular Schwannoma: A Volume and Dosimetric Analysis

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

Hayhurst, Caroline; Monsalves, Eric; Bernstein, Mark

2012-04-01

Purpose: To define clinical and dosimetric predictors of nonauditory adverse radiation effects after radiosurgery for vestibular schwannoma treated with a 12 Gy prescription dose. Methods: We retrospectively reviewed our experience of vestibular schwannoma patients treated between September 2005 and December 2009. Two hundred patients were treated at a 12 Gy prescription dose; 80 had complete clinical and radiological follow-up for at least 24 months (median, 28.5 months). All treatment plans were reviewed for target volume and dosimetry characteristics; gradient index; homogeneity index, defined as the maximum dose in the treatment volume divided by the prescription dose; conformity index; brainstem; andmore » trigeminal nerve dose. All adverse radiation effects (ARE) were recorded. Because the intent of our study was to focus on the nonauditory adverse effects, hearing outcome was not evaluated in this study. Results: Twenty-seven (33.8%) patients developed ARE, 5 (6%) developed hydrocephalus, 10 (12.5%) reported new ataxia, 17 (21%) developed trigeminal dysfunction, 3 (3.75%) had facial weakness, and 1 patient developed hemifacial spasm. The development of edema within the pons was significantly associated with ARE (p = 0.001). On multivariate analysis, only target volume is a significant predictor of ARE (p = 0.001). There is a target volume threshold of 5 cm3, above which ARE are more likely. The treatment plan dosimetric characteristics are not associated with ARE, although the maximum dose to the 5th nerve is a significant predictor of trigeminal dysfunction, with a threshold of 9 Gy. The overall 2-year tumor control rate was 96%. Conclusions: Target volume is the most important predictor of adverse radiation effects, and we identified the significant treatment volume threshold to be 5 cm3. We also established through our series that the maximum tolerable dose to the 5th nerve is 9 Gy.« less

Focusing analytes from 50 μL into 500 pL: On-chip focusing from large sample volumes using isotachophoresis.

PubMed

van Kooten, Xander F; Truman-Rosentsvit, Marianna; Kaigala, Govind V; Bercovici, Moran

2017-09-05

The use of on-chip isotachophoresis assays for diagnostic applications is often limited by the small volumes of standard microfluidic channels. Overcoming this limitation is particularly important for detection of 'discrete' biological targets (such as bacteria) at low concentrations, where the volume of processed liquid in a standard microchannel might not contain any targets. We present a novel microfluidic chip that enables ITP focusing of target analytes from initial sample volumes of 50 μL into a concentrated zone with a volume of 500 pL, corresponding to a 100,000-fold increase in mean concentration, and a 300,000-fold increase in peak concentration. We present design considerations for limiting sample dispersion in such large-volume focusing (LVF) chips and discuss the trade-off between assay time and Joule heating, which ultimately governs the scalability of LVF designs. Finally, we demonstrate a 100-fold improvement of ITP focusing performance in the LVF chip as compared to conventional microchannels, and apply this enhancement to achieve highly sensitive detection of both molecular targets (DNA, down to 10 fM) and whole bacteria (down to 100 cfu/mL).

Proposed Site Treatment Plan (PSTP). Volumes 1 and 2 and Reference Document

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

Helmich, E.; Noller, D.K.; Wierzbicki, K.S.

1994-12-22

The Compliance Plan Volume provides overall schedules with target dates for achieving compliance with the land disposal restrictions (LDR) and contains procedures to establish milestones to be enforced under the Order. Information regarding the technical evaluation of treatment options for SRS mixed wastes is contained in the Background Volume and is provided for informational purposes only.

A pilot prospective feasibility study of organ-at-risk definition using Target Contour Testing/Instructional Computer Software (TaCTICS), a training and evaluation platform for radiotherapy target delineation.

PubMed

Kalpathy-Cramer, Jayashree; Bedrick, Steven D; Boccia, Kelly; Fuller, Clifton D

2011-01-01

Target volume delineation is a critical, but time-consuming step in the creation of radiation therapy plans used in the treatment of many types of cancer. However, variability in target volume definitions can introduce substantial differences in resulting doses to tumors and critical structures. We developed TaCTICS, a web-based educational training software application targeted towards non-expert users. We report on a small, prospective study to evaluate the utility of this online tool in improving conformance of regions-of-interest (ROIs) with a reference set. Eight residents contoured a set of structures for a head-and-neck cancer case. Subsequently, they were provided access to TaCTICS as well as contouring atlases to allow evaluation of their contours in reference to other users as well as reference ROIs. The residents then contoured a second case using these resources. Volume overlap metrics between the users showed a substantial improvement following the intervention. Additionally, 66% of users reported that they found TaCTICS to be a useful educational tool and all participants reported they would like to use TaCTICS to track their contouring skills over the course of their residency.

More Accurate Definition of Clinical Target Volume Based on the Measurement of Microscopic Extensions of the Primary Tumor Toward the Uterus Body in International Federation of Gynecology and Obstetrics Ib-IIa Squamous Cell Carcinoma of the Cervix

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

Xie, Wen-Jia; Wu, Xiao; Xue, Ren-Liang

Purpose: To more accurately define clinical target volume for cervical cancer radiation treatment planning by evaluating tumor microscopic extension toward the uterus body (METU) in International Federation of Gynecology and Obstetrics stage Ib-IIa squamous cell carcinoma of the cervix (SCCC). Patients and Methods: In this multicenter study, surgical resection specimens from 318 cases of stage Ib-IIa SCCC that underwent radical hysterectomy were included. Patients who had undergone preoperative chemotherapy, radiation, or both were excluded from this study. Microscopic extension of primary tumor toward the uterus body was measured. The association between other pathologic factors and METU was analyzed. Results: Microscopicmore » extension toward the uterus body was not common, with only 12.3% of patients (39 of 318) demonstrating METU. The mean (±SD) distance of METU was 0.32 ± 1.079 mm (range, 0-10 mm). Lymphovascular space invasion was associated with METU distance and occurrence rate. A margin of 5 mm added to gross tumor would adequately cover 99.4% and 99% of the METU in the whole group and in patients with lymphovascular space invasion, respectively. Conclusion: According to our analysis of 318 SCCC specimens for METU, using a 5-mm gross tumor volume to clinical target volume margin in the direction of the uterus should be adequate for International Federation of Gynecology and Obstetrics stage Ib-IIa SCCC. Considering the discrepancy between imaging and pathologic methods in determining gross tumor volume extent, we recommend a safer 10-mm margin in the uterine direction as the standard for clinical practice when using MRI for contouring tumor volume.« less

Raytracing and Direct-Drive Targets

NASA Astrophysics Data System (ADS)

Schmitt, Andrew J.; Bates, Jason; Fyfe, David; Eimerl, David

2013-10-01

Accurate simulation of the effects of laser imprinting and drive asymmetries in directly driven targets requires the ability to distinguish between raytrace noise and the intensity structure produced by the spatial and temporal incoherence of optical smoothing. We have developed and implemented a smoother raytrace algorithm for our mpi-parallel radiation hydrodynamics code, FAST3D. The underlying approach is to connect the rays into either sheets (in 2D) or volume-enclosing chunks (in 3D) so that the absorbed energy distribution continuously covers the propagation area illuminated by the laser. We will describe the status and show the different scalings encountered in 2D and 3D problems as the computational size, parallelization strategy, and number of rays is varied. Finally, we show results using the method in current NIKE experimental target simulations and in proposed symmetric and polar direct-drive target designs. Supported by US DoE/NNSA.

Online compensation for target motion with scanned particle beams: simulation environment.

PubMed

Li, Qiang; Groezinger, Sven Oliver; Haberer, Thomas; Rietzel, Eike; Kraft, Gerhard

2004-07-21

Target motion is one of the major limitations of each high precision radiation therapy. Using advanced active beam delivery techniques, such as the magnetic raster scanning system for particle irradiation, the interplay between time-dependent beam and target position heavily distorts the applied dose distribution. This paper presents a simulation environment in which the time-dependent effect of target motion on heavy-ion irradiation can be calculated with dynamically scanned ion beams. In an extension of the existing treatment planning software for ion irradiation of static targets (TRiP) at GSI, the expected dose distribution is calculated as the sum of several sub-distributions for single target motion states. To investigate active compensation for target motion by adapting the position of the therapeutic beam during irradiation, the planned beam positions can be altered during the calculation. Applying realistic parameters to the planned motion-compensation methods at GSI, the effect of target motion on the expected dose uniformity can be simulated for different target configurations and motion conditions. For the dynamic dose calculation, experimentally measured profiles of the beam extraction in time were used. Initial simulations show the feasibility and consistency of an active motion compensation with the magnetic scanning system and reveal some strategies to improve the dose homogeneity inside the moving target. The simulation environment presented here provides an effective means for evaluating the dose distribution for a moving target volume with and without motion compensation. It contributes a substantial basis for the experimental research on the irradiation of moving target volumes with scanned ion beams at GSI which will be presented in upcoming papers.

[Effect of image fusion technology of radioactive particles implantation before and after the planning target and dosimetry].

PubMed

Jiang, Y L; Yu, J P; Sun, H T; Guo, F X; Ji, Z; Fan, J H; Zhang, L J; Li, X; Wang, J J

2017-08-01

Objective: To compare the post-implant target volumes and dosimetric evaluation with pre-plan, the gross tumor volume(GTV) by CT image fusion-based and the manual delineation of target volume in CT guided radioactive seeds implantation. Methods: A total of 10 patients treated under CT-guidance (125)I seed implantation during March 2016 to April 2016 were analyzed in Peking University Third Hospital.All patients underwent pre-operative CT simulation, pre-operative planning, implantation seeds, CT scanning after seed implantation and dosimetric evaluation of GTV.In every patient, post-implant target volumes were delineated by both two methods, and were divided into two groups. Group 1: image fusion pre-implantation simulation and post-operative CT image, then the contours of GTV were automatically performed by brachytherapy treatment planning system; Group 2: the contouring of the GTV on post-operative CT image were performed manually by three senior radiation oncologists independently. The average of three data was sets. Statistical analyses were performed using SPSS software, version 3.2.0. The paired t -test was used to compare the target volumes and D(90) parameters in two modality. Results: In Group 1, average volume of GTV in post-operation group was 12-167(73±56) cm(3). D(90) was 101-153 (142±19)Gy. In Group 2, they were 14-186(80±58)cm(3) and 96-146(122±16) Gy respectively. In both target volumes and D(90), there was no statistical difference between pre-operation and post-operation in Group 1.The D(90) was slightly lower than that of pre-plan group, but there was no statistical difference ( P =0.142); in Group 2, between pre-operation and post-operation group, there was a significant statistical difference in the GTV ( P =0.002). The difference of D(90) was similarly ( P <0.01). Conclusion: The method of delineation of post-implant GTV through fusion pre-implantation simulation and post-operative CT scan images, the contours of GTV are automatically

Temperature Controller System for Gas Gun Targets

NASA Astrophysics Data System (ADS)

Bucholtz, Scott; Sheffield, Stephen

2005-07-01

A temperature controller system capable of heating and cooling gas gun targets over the range -75 C to +200 C was designed and tested. The system uses cold nitrogen gas from a liquid nitrogen Dewar for cooling and compressed air for heating. Two gas flow heaters control the gas temperature for both heating and cooling. One heater controls the temperature of the target mounting plate and the other the temperature of a copper tubing coil surrounding the target. Each heater is separately adjustable, so the target material will achieve a uniform temperature throughout its volume. A magnetic gauge with integrated thermocouples was developed to measure the internal temperature of the target. Using this system shock experiments, including equation-of-state measurements and shock initiation of high explosives, can be performed over a range of initial temperatures. Successful tests were completed on Teflon samples. This work was supported by the NNSA Enhanced Surveillance Campaign through contract DE-ACO4-01AL66850.

Temperature Controller System for Gas Gun Targets

NASA Astrophysics Data System (ADS)

Bucholtz, S. M.; Gehr, R. J.; Rupp, T. D.; Sheffield, S. A.; Robbins, D. L.

2006-07-01

A temperature controller system capable of heating and cooling gas gun targets over the range -75°C to +120°C was designed and tested. The system uses cold nitrogen gas from a liquid nitrogen Dewar for cooling and compressed air for heating. Two gas flow heaters control the gas temperature for both heating and cooling. One heater controls the temperature of the target mounting plate and the other the temperature of a copper tubing coil surrounding the target. Each heater is separately adjustable, so the target material will achieve a uniform temperature throughout its volume. A magnetic gauge membrane with integrated thermocouples was developed to measure the internal temperature of the target. Using this system, multiple magnetic gauge shock experiments, including equation-of-state measurements and shock initiation of high explosives, can be performed over a range of initial temperatures. Successful heating and cooling tests were completed on Teflon samples.

High-Target Versus Low-Target Blood Pressure Management During Cardiopulmonary Bypass to Prevent Cerebral Injury in Cardiac Surgery Patients: A Randomized Controlled Trial.

PubMed

Vedel, Anne G; Holmgaard, Frederik; Rasmussen, Lars S; Langkilde, Annika; Paulson, Olaf B; Lange, Theis; Thomsen, Carsten; Olsen, Peter Skov; Ravn, Hanne Berg; Nilsson, Jens C

2018-04-24

Cerebral injury is an important complication after cardiac surgery with the use of cardiopulmonary bypass. The rate of overt stroke after cardiac surgery is 1% to 2%, whereas silent strokes, detected by diffusion-weighted magnetic resonance imaging, are found in up to 50% of patients. It is unclear whether a higher versus a lower blood pressure during cardiopulmonary bypass reduces cerebral infarction in these patients. In a patient- and assessor-blinded randomized trial, we allocated patients to a higher (70-80 mm Hg) or lower (40-50 mm Hg) target for mean arterial pressure by the titration of norepinephrine during cardiopulmonary bypass. Pump flow was fixed at 2.4 L·min -1 ·m -2 . The primary outcome was the total volume of new ischemic cerebral lesions (summed in millimeters cubed), expressed as the difference between diffusion-weighted imaging conducted preoperatively and again postoperatively between days 3 and 6. Secondary outcomes included diffusion-weighted imaging-evaluated total number of new ischemic lesions. Among the 197 enrolled patients, mean (SD) age was 65.0 (10.7) years in the low-target group (n=99) and 69.4 (8.9) years in the high-target group (n=98). Procedural risk scores were comparable between groups. Overall, diffusion-weighted imaging revealed new cerebral lesions in 52.8% of patients in the low-target group versus 55.7% in the high-target group ( P =0.76). The primary outcome of volume of new cerebral lesions was comparable between groups, 25 mm 3 (interquartile range, 0-118 mm 3 ; range, 0-25 261 mm 3 ) in the low-target group versus 29 mm 3 (interquartile range, 0-143 mm 3 ; range, 0-22 116 mm 3 ) in the high-target group (median difference estimate, 0; 95% confidence interval, -25 to 0.028; P =0.99), as was the secondary outcome of number of new lesions (1 [interquartile range, 0-2; range, 0-24] versus 1 [interquartile range, 0-2; range, 0-29] respectively; median difference estimate, 0; 95% confidence interval, 0-0; P =0

Locoregional control after intensity-modulated radiotherapy for nasopharyngeal carcinoma with an anatomy-based target definition.

PubMed

Kawashima, Mitsuhiko; Ariji, Takaki; Kameoka, Satoru; Ueda, Takashi; Kohno, Ryosuke; Nishio, Teiji; Arahira, Satoko; Motegi, Atsushi; Zenda, Sadamoto; Akimoto, Tetsuo; Tahara, Makoto; Hayashi, Ryuichi

2013-12-01

The objective of the study was to evaluate locoregional control after intensity-modulated radiotherapy for nasopharyngeal cancer using a target definition along with anatomical boundaries. Forty patients with biopsy-proven squamous cell or non-keratinizing carcinoma of the nasopharynx who underwent intensity-modulated radiotherapy between April 2006 and November 2009 were reviewed. There were 10 females and 30 males with a median age of 48 years (range, 17-74 years). More than half of the patients had T3/4 (n = 21) and/or N2/3 (n = 24) disease. Intensity-modulated radiotherapy was administered as 70 Gy/33 fractions with or without concomitant chemotherapy. The clinical target volume was contoured along with muscular fascia or periosteum, and the prescribed radiotherapy dose was determined for each anatomical compartment and lymph node level in the head and neck. One local recurrence was observed at Meckel's cave on the periphery of the high-risk clinical target volume receiving a total dose of <63 Gy. Otherwise, six locoregional failures were observed within irradiated volume receiving 70 Gy. Local and nodal control rates at 3 years were 91 and 89%, respectively. Adverse events were acceptable, and 25 (81%) of 31 patients who were alive without recurrence at 2 years had xerostomia of ≤Grade 1. The overall survival rate at 3 years was 87%. Target definition along with anatomically defined boundaries was feasible without compromise of the therapeutic ratio. It is worth testing this method further to minimize the unnecessary irradiated volume and to standardize the target definition in intensity-modulated radiotherapy for nasopharyngeal cancer.

Moderator's view: High-volume plasma exchange: pro, con and consensus.

PubMed

Kaplan, Andre A

2017-09-01

I have been asked to comment on the pro and con opinions regarding high-volume plasma exchange. The authors of both positions have provided cogent arguments and a reasonable approach to choosing the exchange volume for any given therapeutic plasma exchange. The major issue of relevance in this discussion is the nature of the toxins targeted for removal. These parameters include molecular weight, the apparent volume of distribution, the degree of protein binding, the biologic and chemical half-life, and the severity and rapidity of its toxicity. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Prospective feasibility trial of radiotherapy target definition for head and neck cancer using 3-dimensional PET and CT imaging.

PubMed

Scarfone, Christopher; Lavely, William C; Cmelak, Anthony J; Delbeke, Dominique; Martin, William H; Billheimer, Dean; Hallahan, Dennis E

2004-04-01

The aim of this investigation was to evaluate the influence and accuracy of (18)F-FDG PET in target volume definition as a complementary modality to CT for patients with head and neck cancer (HNC) using dedicated PET and CT scanners. Six HNC patients were custom fitted with head and neck and upper body immobilization devices, and conventional radiotherapy CT simulation was performed together with (18)F-FDG PET imaging. Gross target volume (GTV) and pathologic nodal volumes were first defined in the conventional manner based on CT. A segmentation and surface-rendering registration technique was then used to coregister the (18)F-FDG PET and CT planning image datasets. (18)F-FDG PET GTVs were determined and displayed simultaneously with the CT contours. CT GTVs were then modified based on the PET data to form final PET/CT treatment volumes. Five-field intensity-modulated radiation therapy (IMRT) was then used to demonstrate dose targeting to the CT GTV or the PET/CT GTV. One patient was PET-negative after induction chemotherapy. The CT GTV was modified in all remaining patients based on (18)F-FDG PET data. The resulting PET/CT GTV was larger than the original CT volume by an average of 15%. In 5 cases, (18)F-FDG PET identified active lymph nodes that corresponded to lymph nodes contoured on CT. The pathologically enlarged CT lymph nodes were modified to create final lymph node volumes in 3 of 5 cases. In 1 of 6 patients, (18)F-FDG-avid lymph nodes were not identified as pathologic on CT. In 2 of 6 patients, registration of the independently acquired PET and CT data using segmentation and surface rendering resulted in a suboptimal alignment and, therefore, had to be repeated. Radiotherapy planning using IMRT demonstrated the capability of this technique to target anatomic or anatomic/physiologic target volumes. In this manner, metabolically active sites can be intensified to greater daily doses. Inclusion of (18)F-FDG PET data resulted in modified target volumes in

SINGLE INSTITUTION VARIABILITY IN INTENSITY MODULATED RADIATION TARGET DELINEATION FOR CANINE NASAL NEOPLASIA.

PubMed

Christensen, Neil I; Forrest, Lisa J; White, Pamela J; Henzler, Margaret; Turek, Michelle M

2016-11-01

Contouring variability is a significant barrier to the accurate delivery and reporting of radiation therapy. The aim of this descriptive study was to determine the variation in contouring radiation targets and organs at risk by participants within our institution. Further, we also aimed to determine if all individuals contoured the same normal tissues. Two canine nasal tumor datasets were selected and contoured by two ACVR-certified radiation oncologists and two radiation oncology residents from the same institution. Eight structures were consistently contoured including the right and left eye, the right and left lens, brain, the gross tumor volume (GTV), clinical target volume (CTV), and planning target volume (PTV). Spinal cord, hard and soft palate, and bulla were contoured on 50% of datasets. Variation in contouring occurred in both targets and normal tissues at risk and was particularly significant for the GTV, CTV, and PTV. The mean metric score and dice similarity coefficient were below the threshold criteria in 37.5-50% and 12.5-50% of structures, respectively, quantitatively indicating contouring variation. This study refutes our hypothesis that minimal variation in target and normal tissue delineation occurs. The variation in contouring may contribute to different tumor response and toxicity for any given patient. Our results also highlight the difficulty associated with replication of published radiation protocols or treatments, as even with replete contouring description the outcome of treatment is still fundamentally influenced by the individual contouring the patient. © 2016 American College of Veterinary Radiology.

SU-F-J-115: Target Volume and Artifact Evaluation of a New Device-Less 4D CT Algorithm

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

Martin, R; Pan, T

2016-06-15

Purpose: 4DCT is often used in radiation therapy treatment planning to define the extent of motion of the visible tumor (IGTV). Recent available software allows 4DCT images to be created without the use of an external motion surrogate. This study aims to compare this device-less algorithm to a standard device-driven technique (RPM) in regards to artifacts and the creation of treatment volumes. Methods: 34 lung cancer patients who had previously received a cine 4DCT scan on a GE scanner with an RPM determined respiratory signal were selected. Cine images were sorted into 10 phases based on both the RPM signalmore » and the device-less algorithm. Contours were created on standard and device-less maximum intensity projection (MIP) images using a region growing algorithm and manual adjustment to remove other structures. Variations in measurements due to intra-observer differences in contouring were assessed by repeating a subset of 6 patients 2 additional times. Artifacts in each phase image were assessed using normalized cross correlation at each bed position transition. A score between +1 (artifacts “better” in all phases for device-less) and −1 (RPM similarly better) was assigned for each patient based on these results. Results: Device-less IGTV contours were 2.1 ± 1.0% smaller than standard IGTV contours (not significant, p = 0.15). The Dice similarity coefficient (DSC) was 0.950 ± 0.006 indicating good similarity between the contours. Intra-observer variation resulted in standard deviations of 1.2 percentage points in percent volume difference and 0.005 in DSC measurements. Only two patients had improved artifacts with RPM, and the average artifact score (0.40) was significantly greater than zero. Conclusion: Device-less 4DCT can be used in place of the standard method for target definition due to no observed difference between standard and device-less IGTVs. Phase image artifacts were significantly reduced with the device-less method.« less

Component extraction on CT volumes of assembled products using geometric template matching

NASA Astrophysics Data System (ADS)

Muramatsu, Katsutoshi; Ohtake, Yutaka; Suzuki, Hiromasa; Nagai, Yukie

2017-03-01

As a method of non-destructive internal inspection, X-ray computed tomography (CT) is used not only in medical applications but also for product inspection. Some assembled products can be divided into separate components based on density, which is known to be approximately proportional to CT values. However, components whose densities are similar cannot be distinguished using the CT value driven approach. In this study, we proposed a new component extraction algorithm from the CT volume, using a set of voxels with an assigned CT value with the surface mesh as the template rather than the density. The method has two main stages: rough matching and fine matching. At the rough matching stage, the position of candidate targets is identified roughly from the CT volume, using the template of the target component. At the fine matching stage, these candidates are precisely matched with the templates, allowing the correct position of the components to be detected from the CT volume. The results of two computational experiments showed that the proposed algorithm is able to extract components with similar density within the assembled products on CT volumes.

Significant Reduction of Late Toxicities in Patients With Extremity Sarcoma Treated With Image-Guided Radiation Therapy to a Reduced Target Volume: Results of Radiation Therapy Oncology Group RTOG-0630 Trial.

PubMed

Wang, Dian; Zhang, Qiang; Eisenberg, Burton L; Kane, John M; Li, X Allen; Lucas, David; Petersen, Ivy A; DeLaney, Thomas F; Freeman, Carolyn R; Finkelstein, Steven E; Hitchcock, Ying J; Bedi, Manpreet; Singh, Anurag K; Dundas, George; Kirsch, David G

2015-07-10

We performed a multi-institutional prospective phase II trial to assess late toxicities in patients with extremity soft tissue sarcoma (STS) treated with preoperative image-guided radiation therapy (IGRT) to a reduced target volume. Patients with extremity STS received IGRT with (cohort A) or without (cohort B) chemotherapy followed by limb-sparing resection. Daily pretreatment images were coregistered with digitally reconstructed radiographs so that the patient position could be adjusted before each treatment. All patients received IGRT to reduced tumor volumes according to strict protocol guidelines. Late toxicities were assessed at 2 years. In all, 98 patients were accrued (cohort A, 12; cohort B, 86). Cohort A was closed prematurely because of poor accrual and is not reported. Seventy-nine eligible patients from cohort B form the basis of this report. At a median follow-up of 3.6 years, five patients did not have surgery because of disease progression. There were five local treatment failures, all of which were in field. Of the 57 patients assessed for late toxicities at 2 years, 10.5% experienced at least one grade ≥ 2 toxicity as compared with 37% of patients in the National Cancer Institute of Canada SR2 (CAN-NCIC-SR2: Phase III Randomized Study of Pre- vs Postoperative Radiotherapy in Curable Extremity Soft Tissue Sarcoma) trial receiving preoperative radiation therapy without IGRT (P < .001). The significant reduction of late toxicities in patients with extremity STS who were treated with preoperative IGRT and absence of marginal-field recurrences suggest that the target volumes used in the Radiation Therapy Oncology Group RTOG-0630 (A Phase II Trial of Image-Guided Preoperative Radiotherapy for Primary Soft Tissue Sarcomas of the Extremity) study are appropriate for preoperative IGRT for extremity STS. © 2015 by American Society of Clinical Oncology.

Hierarchical imaging: a new concept for targeted imaging of large volumes from cells to tissues.

PubMed

Wacker, Irene; Spomer, Waldemar; Hofmann, Andreas; Thaler, Marlene; Hillmer, Stefan; Gengenbach, Ulrich; Schröder, Rasmus R

2016-12-12

Imaging large volumes such as entire cells or small model organisms at nanoscale resolution seemed an unrealistic, rather tedious task so far. Now, technical advances have lead to several electron microscopy (EM) large volume imaging techniques. One is array tomography, where ribbons of ultrathin serial sections are deposited on solid substrates like silicon wafers or glass coverslips. To ensure reliable retrieval of multiple ribbons from the boat of a diamond knife we introduce a substrate holder with 7 axes of translation or rotation specifically designed for that purpose. With this device we are able to deposit hundreds of sections in an ordered way in an area of 22 × 22 mm, the size of a coverslip. Imaging such arrays in a standard wide field fluorescence microscope produces reconstructions with 200 nm lateral resolution and 100 nm (the section thickness) resolution in z. By hierarchical imaging cascades in the scanning electron microscope (SEM), using a new software platform, we can address volumes from single cells to complete organs. In our first example, a cell population isolated from zebrafish spleen, we characterize different cell types according to their organelle inventory by segmenting 3D reconstructions of complete cells imaged with nanoscale resolution. In addition, by screening large numbers of cells at decreased resolution we can define the percentage at which different cell types are present in our preparation. With the second example, the root tip of cress, we illustrate how combining information from intermediate resolution data with high resolution data from selected regions of interest can drastically reduce the amount of data that has to be recorded. By imaging only the interesting parts of a sample considerably less data need to be stored, handled and eventually analysed. Our custom-designed substrate holder allows reproducible generation of section libraries, which can then be imaged in a hierarchical way. We demonstrate, that EM

Evolution of egg target size: an analysis of selection on correlated characters.

PubMed

Podolsky, R D

2001-12-01

In broadcast-spawning marine organisms, chronic sperm limitation should select for traits that improve chances of sperm-egg contact. One mechanism may involve increasing the size of the physical or chemical target for sperm. However, models of fertilization kinetics predict that increasing egg size can reduce net zygote production due to an associated decline in fecundity. An alternate method for increasing physical target size is through addition of energetically inexpensive external structures, such as the jelly coats typical of eggs in species from several phyla. In selection experiments on eggs of the echinoid Dendraster excentricus, in which sperm was used as the agent of selection, eggs with larger overall targets were favored in fertilization. Actual shifts in target size following selection matched quantitative predictions of a model that assumed fertilization was proportional to target size. Jelly volume and ovum volume, two characters that contribute to target size, were correlated both within and among females. A cross-sectional analysis of selection partitioned the independent effects of these characters on fertilization success and showed that they experience similar direct selection pressures. Coupled with data on relative organic costs of the two materials, these results suggest that, under conditions where fertilization is limited by egg target size, selection should favor investment in low-cost accessory structures and may have a relatively weak effect on the evolution of ovum size.

SU-F-J-95: Impact of Shape Complexity On the Accuracy of Gradient-Based PET Volume Delineation

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

Dance, M; Wu, G; Gao, Y

2016-06-15

Purpose: Explore correlation of tumor complexity shape with PET target volume accuracy when delineated with gradient-based segmentation tool. Methods: A total of 24 clinically realistic digital PET Monte Carlo (MC) phantoms of NSCLC were used in the study. The phantom simulated 29 thoracic lesions (lung primary and mediastinal lymph nodes) of varying size, shape, location, and {sup 18}F-FDG activity. A program was developed to calculate a curvature vector along the outline and the standard deviation of this vector was used as a metric to quantify a shape’s “complexity score”. This complexity score was calculated for standard geometric shapes and MC-generatedmore » target volumes in PET phantom images. All lesions were contoured using a commercially available gradient-based segmentation tool and the differences in volume from the MC-generated volumes were calculated as the measure of the accuracy of segmentation. Results: The average absolute percent difference in volumes between the MC-volumes and gradient-based volumes was 11% (0.4%–48.4%). The complexity score showed strong correlation with standard geometric shapes. However, no relationship was found between the complexity score and the accuracy of segmentation by gradient-based tool on MC simulated tumors (R{sup 2} = 0.156). When the lesions were grouped into primary lung lesions and mediastinal/mediastinal adjacent lesions, the average absolute percent difference in volumes were 6% and 29%, respectively. The former group is more isolated and the latter is more surround by tissues with relatively high SUV background. Conclusion: The complexity shape of NSCLC lesions has little effect on the accuracy of the gradient-based segmentation method and thus is not a good predictor of uncertainty in target volume delineation. Location of lesion within a relatively high SUV background may play a more significant role in the accuracy of gradient-based segmentation.« less

SU-E-T-513: Investigating Dose of Internal Target Volume After Correcting for Tissue Heterogeneity in SBRT Lung Plans with Homogeneity Calculation

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

Qi, P; Zhuang, T; Magnelli, A

2015-06-15

Purpose It was recommended to use the prescription of 54 Gy/3 with heterogeneity corrections for previously established dose scheme of 60 Gy/3 with homogeneity calculation. This study is to investigate dose coverage for the internal target volume (ITV) with and without heterogeneity correction. Methods Thirty patients who received stereotactic body radiotherapy (SBRT) to a dose of 60 Gy in 3 fractions with homogeneous planning for early stage non-small-cell lung cancer (NSCLC) were selected. ITV was created either from 4DCT scans or a fusion of multi-phase respiratory scans. Planning target volume (PTV) was a 5 mm expansion of the ITV. Formore » this study, we recalculated homogeneous clinical plans using heterogeneity corrections with monitor units set as clinically delivered. All plans were calculated with 3 mm dose grids and collapsed cone convolution algorithm. To account for uncertainties from tumor delineation and image-guided radiotherapy, a structure ITV2mm was created by expanding ITV with 2 mm margins. Dose coverage to the PTV, ITV and ITV2mm were compared with a student paired t-test. Results With heterogeneity corrections, the PTV V60Gy decreased by 10.1% ± 18.4% (p<0.01) while the maximum dose to the PTV increased by 3.7 ± 4.3% (p<0.01). With and without corrections, D99% was 65.8 ± 4.0 Gy and 66.7 ± 4.8 Gy (p=0.15) for the ITV, and 63.9 ± 3.4 Gy and 62.9 ± 4.6 Gy for the ITV2mm (p=0.22), respectively. The mean dose to the ITV and ITV2mm increased 3.6% ± 4.7% (p<0.01) and 2.3% ± 5.2% (p=0.01) with heterogeneity corrections. Conclusion After heterogeneity correction, the peripheral coverage of the PTV decreased to approximately 54 Gy, but D99% of the ITV and ITV2mm was unchanged and the mean dose to the ITV and ITV2mm was increased. Clinical implication of these results requires more investigation.« less

Small-Volume Injections: Evaluation of Volume Administration Deviation From Intended Injection Volumes.

PubMed

Muffly, Matthew K; Chen, Michael I; Claure, Rebecca E; Drover, David R; Efron, Bradley; Fitch, William L; Hammer, Gregory B

2017-10-01

In the perioperative period, anesthesiologists and postanesthesia care unit (PACU) nurses routinely prepare and administer small-volume IV injections, yet the accuracy of delivered medication volumes in this setting has not been described. In this ex vivo study, we sought to characterize the degree to which small-volume injections (≤0.5 mL) deviated from the intended injection volumes among a group of pediatric anesthesiologists and pediatric postanesthesia care unit (PACU) nurses. We hypothesized that as the intended injection volumes decreased, the deviation from those intended injection volumes would increase. Ten attending pediatric anesthesiologists and 10 pediatric PACU nurses each performed a series of 10 injections into a simulated patient IV setup. Practitioners used separate 1-mL tuberculin syringes with removable 18-gauge needles (Becton-Dickinson & Company, Franklin Lakes, NJ) to aspirate 5 different volumes (0.025, 0.05, 0.1, 0.25, and 0.5 mL) of 0.25 mM Lucifer Yellow (LY) fluorescent dye constituted in saline (Sigma Aldrich, St. Louis, MO) from a rubber-stoppered vial. Each participant then injected the specified volume of LY fluorescent dye via a 3-way stopcock into IV tubing with free-flowing 0.9% sodium chloride (10 mL/min). The injected volume of LY fluorescent dye and 0.9% sodium chloride then drained into a collection vial for laboratory analysis. Microplate fluorescence wavelength detection (Infinite M1000; Tecan, Mannedorf, Switzerland) was used to measure the fluorescence of the collected fluid. Administered injection volumes were calculated based on the fluorescence of the collected fluid using a calibration curve of known LY volumes and associated fluorescence.To determine whether deviation of the administered volumes from the intended injection volumes increased at lower injection volumes, we compared the proportional injection volume error (loge [administered volume/intended volume]) for each of the 5 injection volumes using a linear

Evaluation of target coverage and margins adequacy during CyberKnife Lung Optimized Treatment.

PubMed

Ricotti, Rosalinda; Seregni, Matteo; Ciardo, Delia; Vigorito, Sabrina; Rondi, Elena; Piperno, Gaia; Ferrari, Annamaria; Zerella, Maria Alessia; Arculeo, Simona; Francia, Claudia Maria; Sibio, Daniela; Cattani, Federica; De Marinis, Filippo; Spaggiari, Lorenzo; Orecchia, Roberto; Riboldi, Marco; Baroni, Guido; Jereczek-Fossa, Barbara Alicja

2018-04-01

Evaluation of target coverage and verification of safety margins, in motion management strategies implemented by Lung Optimized Treatment (LOT) module in CyberKnife system. Three fiducial-less motion management strategies provided by LOT can be selected according to tumor visibility in the X ray images acquired during treatment. In 2-view modality the tumor is visible in both X ray images and full motion tracking is performed. In 1-view modality the tumor is visible in a single X ray image, therefore, motion tracking is combined with an internal target volume (ITV)-based margin expansion. In 0-view modality the lesion is not visible, consequently the treatment relies entirely on an ITV-based approach. Data from 30 patients treated in 2-view modality were selected providing information on the three-dimensional tumor motion in correspondence to each X ray image. Treatments in 1-view and 0-view modalities were simulated by processing log files and planning volumes. Planning target volume (PTV) margins were defined according to the tracking modality: end-exhale clinical target volume (CTV) + 3 mm in 2-view and ITV + 5 mm in 0-view. In the 1-view scenario, the ITV encompasses only tumor motion along the non-visible direction. Then, non-uniform ITV to PTV margins were applied: 3 mm and 5 mm in the visible and non-visible direction, respectively. We defined the coverage of each voxel of the CTV as the percentage of X ray images where such voxel was included in the PTV. In 2-view modality coverage was calculated as the intersection between the CTV centred on the imaged target position and the PTV centred on the predicted target position, as recorded in log files. In 1-view modality, coverage was calculated as the intersection between the CTV centred on the imaged target position and the PTV centred on the projected predictor data. In 0-view modality coverage was calculated as the intersection between the CTV centred on the imaged target position and the non

Consequences of anorectal cancer atlas implementation in the cooperative group setting: radiobiologic analysis of a prospective randomized in silico target delineation study.

PubMed

Mavroidis, Panayiotis; Giantsoudis, Drosoula; Awan, Musaddiq J; Nijkamp, Jasper; Rasch, Coen R N; Duppen, Joop C; Thomas, Charles R; Okunieff, Paul; Jones, William E; Kachnic, Lisa A; Papanikolaou, Niko; Fuller, Clifton D

2014-09-01

The aim of this study is to ascertain the subsequent radiobiological impact of using a consensus guideline target volume delineation atlas. Using a representative case and target volume delineation instructions derived from a proposed IMRT rectal cancer clinical trial, gross tumor volume (GTV) and clinical/planning target volumes (CTV/PTV) were contoured by 13 physician observers (Phase 1). The observers were then randomly assigned to follow (atlas) or not-follow (control) a consensus guideline/atlas for anorectal cancers, and instructed to re-contour the same case (Phase 2). The atlas group was found to have increased tumor control probability (TCP) after the atlas intervention for both the CTV (p<0.0001) and PTV1 (p=0.0011) with decreasing normal tissue complication probability (NTCP) for small intestine, while the control group did not. Additionally, the atlas group had reduced variance in TCP for all target volumes and reduced variance in NTCP for the bowel. In Phase 2, the atlas group had increased TCP relative to the control for CTV (p=0.03). Visual atlas and consensus treatment guideline usage in the development of rectal cancer IMRT treatment plans reduced the inter-observer radiobiological variation, with clinically relevant TCP alteration for CTV and PTV volumes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

MO-F-CAMPUS-T-02: Optimizing Orientations of Hundreds of Intensity-Modulated Beams to Treat Multiple Brain Targets

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

Ma, L; Dong, P; Larson, D

Purpose: To investigate a new modulated beam orientation optimization (MBOO) approach maximizing treatment planning quality for the state-of-the-art flattening filter free (FFF) beam that has enabled rapid treatments of multiple brain targets. Methods: MBOO selects and optimizes a large number of intensity-modulated beams (400 or more) from all accessible beam angles surrounding a patient’s skull. The optimization algorithm was implemented on a standalone system that interfaced with the 3D Dicom images and structure sets. A standard published data set that consisted of 1 to 12 metastatic brain tumor combinations was selected for MBOO planning. The planning results from various coplanarmore » and non-coplanar configurations via MBOO were then compared with the results obtained from a clinical volume modulated arc therapy (VMAT) delivery system (Truebeam RapidArc, Varian Oncology). Results: When planning a few number of targets (n<4), MBOO produced results equivalent to non-coplanar multi-arc VMAT planning in terms of target volume coverage and normal tissue sparing. For example, the 12-Gy and 4-Gy normal brain volumes for the 3-target plans differed by less than 1 mL ( 3.0 mLvs 3.8 mL; and 35.2 mL vs 36.3 mL, respectively) for MBOO versus VMAT. However, when planning a larger number of targets (n≥4), MBOO significantly reduced the dose to the normal brain as compared to VMAT, though the target volume coverage was equivalent. For example, the 12-Gy and 4-Gy normal brain volumes for the 12-target plans were 10.8 mL vs. 18.0 mL and 217.9 mL vs. 390.0 mL, respectively for the non-coplanar MBOO versus the non-coplanar VMAT treatment plans, yielding a reduction in volume of more than 60% for the case. Conclusion: MBOO is a unique approach for maximizing normal tissue sparing when treating a large number (n≥4) of brain tumors with FFF linear accelerators. Dr Ma and Dr Sahgal are currently on the board of international society of stereotactic radiosurgery. Dr Sahgal

Dose-volume histogram prediction using density estimation.

PubMed

Skarpman Munter, Johanna; Sjölund, Jens

2015-09-07

Knowledge of what dose-volume histograms can be expected for a previously unseen patient could increase consistency and quality in radiotherapy treatment planning. We propose a machine learning method that uses previous treatment plans to predict such dose-volume histograms. The key to the approach is the framing of dose-volume histograms in a probabilistic setting.The training consists of estimating, from the patients in the training set, the joint probability distribution of some predictive features and the dose. The joint distribution immediately provides an estimate of the conditional probability of the dose given the values of the predictive features. The prediction consists of estimating, from the new patient, the distribution of the predictive features and marginalizing the conditional probability from the training over this. Integrating the resulting probability distribution for the dose yields an estimate of the dose-volume histogram.To illustrate how the proposed method relates to previously proposed methods, we use the signed distance to the target boundary as a single predictive feature. As a proof-of-concept, we predicted dose-volume histograms for the brainstems of 22 acoustic schwannoma patients treated with stereotactic radiosurgery, and for the lungs of 9 lung cancer patients treated with stereotactic body radiation therapy. Comparing with two previous attempts at dose-volume histogram prediction we find that, given the same input data, the predictions are similar.In summary, we propose a method for dose-volume histogram prediction that exploits the intrinsic probabilistic properties of dose-volume histograms. We argue that the proposed method makes up for some deficiencies in previously proposed methods, thereby potentially increasing ease of use, flexibility and ability to perform well with small amounts of training data.

Radiation Dose-Volume Effects and the Penile Bulb

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

Roach, Mack, E-mail: mroach@radonc.ucsf.ed; Nam, Jiho; Gagliardi, Giovanna

2010-03-01

The dose, volume, and clinical outcome data for penile bulb are reviewed for patients treated with external-beam radiotherapy. Most, but not all, studies find an association between impotence and dosimetric parameters (e.g., threshold doses) and clinical factors (e.g., age, comorbid diseases). According to the data available, it is prudent to keep the mean dose to 95% of the penile bulb volume to <50 Gy. It may also be prudent to limit the D70 and D90 to 70 Gy and 50 Gy, respectively, but coverage of the planning target volume should not be compromised. It is acknowledged that the penile bulbmore » may not be the critical component of the erectile apparatus, but it seems to be a surrogate for yet to be determined structure(s) critical for erectile function for at least some techniques.« less

Heating of solid targets with laser pulses

NASA Technical Reports Server (NTRS)

Bechtel, J. H.

1975-01-01

Analytical and numerical solutions to the heat-conduction equation are obtained for the heating of absorbing media with pulsed lasers. The spatial and temporal form of the temperature is determined using several different models of the laser irradiance. Both surface and volume generation of heat are discussed. It is found that if the depth of thermal diffusion for the laser-pulse duration is large compared to the optical-attenuation depth, the surface- and volume-generation models give nearly identical results. However, if the thermal-diffusion depth for the laser-pulse duration is comparable to or less than the optical-attenuation depth, the surface-generation model can give significantly different results compared to the volume-generation model. Specific numerical results are given for a tungsten target irradiated by pulses of different temporal durations and the implications of the results are discussed with respect to the heating of metals by picosecond laser pulses.

SU-F-J-148: A Collapsed Cone Algorithm Can Be Used for Quality Assurance for Monaco Treatment Plans for the MR-Linac

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

Hackett, S; Asselen, B van; Wolthaus, J

2016-06-15

Purpose: Treatment plans for the MR-linac, calculated in Monaco v5.19, include direct simulation of the effects of the 1.5T B{sub 0}-field. We tested the feasibility of using a collapsed-cone (CC) algorithm in Oncentra, which does not account for effects of the B{sub 0}-field, as a fast online, independent 3D check of dose calculations. Methods: Treatment plans for six patients were generated in Monaco with a 6 MV FFF beam and the B{sub 0}-field. All plans were recalculated with a CC model of the same beam. Plans for the same patients were also generated in Monaco without the B{sub 0}-field. Themore » mean dose (Dmean) and doses to 10% (D10%) and 90% (D90%) of the volume were determined, as percentages of the prescribed dose, for target volumes and OARs in each calculated dose distribution. Student’s t-tests between paired parameters from Monaco plans and corresponding CC calculations were performed. Results: Figure 1 shows an example of the difference between dose distributions calculated in Monaco, with the B{sub 0}-field, and the CC algorithm. Figure 2 shows distributions of (absolute) difference between parameters for Monaco plans, with the B{sub 0}-field, and CC calculations. The Dmean and D90% values for the CTVs and PTVs were significantly different, but differences in dose distributions arose predominantly at the edges of the target volumes. Inclusion of the B{sub 0}-field had little effect on agreement of the Dmean values, as illustrated by Figure 3, nor on agreement of the D10% and D90% values. Conclusion: Dose distributions recalculated with a CC algorithm show good agreement with those calculated with Monaco, for plans both with and without the B{sub 0}-field, indicating that the CC algorithm could be used to check online treatment planning for the MRlinac. Agreement for a wider range of treatment sites, and the feasibility of using the γ-test as a simple pass/fail criterion, will be investigated.« less

Adjuvant radiation therapy for bladder cancer: A dosimetric comparison of techniques

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

Baumann, Brian C.; Noa, Kate; Wileyto, E. Paul

Trials of adjuvant radiation after cystectomy are under development. There are no studies comparing radiation techniques to inform trial design. This study assesses the effect on bowel and rectal dose of 3 different modalities treating 2 proposed alternative clinical target volumes (CTVs). Contours of the bowel, rectum, CTV-pelvic sidewall (common/internal/external iliac and obturator nodes), and CTV-comprehensive (CTV-pelvic sidewall plus cystectomy bed and presacral regions) were drawn on simulation images of 7 post-cystectomy patients. We optimized 3-dimensional conformal radiation (3-D), intensity-modulated radiation (IMRT), and single-field uniform dose (SFUD) scanning proton plans for each CTV. Mixed models regression was used to comparemore » plans for bowel and rectal volumes exposed to 35% (V{sub 35%}), 65% (V{sub 65%}), and 95% (V{sub 95%}) of the prescribed dose. For any given treatment modality, treating the larger CTV-comprehensive volume compared with treating only the CTV-pelvic sidewall nodes significantly increased rectal dose (V{sub 35%} {sub rectum}, V{sub 65%} {sub rectum}, and V{sub 95%} {sub rectum}; p < 0.001 for all comparisons), but it did not produce significant differences in bowel dose (V{sub 95%} {sub bowel}, V{sub 65%} {sub bowel}, or V{sub 35%} {sub bowel}). The 3-D plans, compared with both the IMRT and the SFUD plans, had a significantly greater V{sub 65%} {sub bowel} and V{sub 95%} {sub bowel} for each proposed CTV (p < 0.001 for all comparisons). The effect of treatment modality on rectal dosimetry differed by CTV, but it generally favored the IMRT and the SFUD plans over the 3-D plans. Comparison of the IMRT plan vs the SFUD plan yielded mixed results with no consistent advantage for the SFUD plan over the IMRT plan. Targeting a CTV that spares the cystectomy bed and presacral region may marginally improve rectal toxicity but would not be expected to improve the bowel toxicity associated with any given modality of adjuvant

Glucosamine-anchored doxorubicin-loaded targeted nano-niosomes: pharmacokinetic, toxicity and pharmacodynamic evaluation.

PubMed

Pawar, Smita; Shevalkar, Ganesh; Vavia, Pradeep

2016-09-01

Efficacy of anticancer drug is limited due to non-selectivity and toxicities allied with the drug; therefore the heart of the present work is to formulate drug delivery systems targeted selectively towards cancer cells with minimal toxicity to normal cells. Targeted drug delivery system of doxorubicin (DOX)-loaded niosomes using synthesized N-lauryl glucosamine (NLG) as a targeting ligand. NLG-anchored DOX niosomes were developed using ethanol injection method. Developed niosomes had particle size <150 nm and high entrapment efficiency ∼90%. In vivo pharmacokinetics exhibited long circulating nature of targeted niosomes with improved bioavailability, which significantly reduced CL and Vd than DOX solution and non-targeted niosomes (35 fold and 2.5 fold, respectively). Tissue-distribution study and enzymatic assays revealed higher concentration of DOX solution in heart while no toxicity to major organs with developed targeted niosomes was observed. Solid skin melanoma tumor model in mice manifested the commendable targeting potential of targeted niosomes with significant reduction in tumor volume and high % survival rate without drop in body weight in comparison with DOX solution and non-targeted niosomes of DOX. The glucosamine-anchored DOX-loaded targeted niosomes showed its potential in cancer targeted drug therapy with reduced toxicity. Abbreviations ALT alanine transaminase CL clearance CPK creatinine phosphokinase DOX doxorubicin EDC.HCL ethyl carbidimide hydrochloride GLUT glucose transporter GSH glutathione S-transferase LDH lactate dehydrogenase LHRH luteinizing hormone-releasing hormone MDA malonaldehyde NHS N-hydroxy succinimide NLG N-lauryl glucosamine NTAR DoxNio non-targeted doxorubicin niosomes PBS phosphate buffer saline RGD argynyl glycyl aspartic acid SGOT serum glutamate oxaloacetate transaminase SGPT serum glutamate pyruvate transaminase SOD superoxide dismutase TAR DoxNio targeted doxorubicin niosomes Vd volume of distribution.

A novel, volumizing cosmetic formulation significantly improves the appearance of target Glabellar lines, nasolabial folds, and crow's feet in a double-blind, vehicle-controlled clinical trial.

PubMed

Farris, Patricia K; Edison, Brenda L; Weinkauf, Ronni L; Green, Barbara A

2014-01-01

Facial lines and wrinkles are caused by many factors including constant exposure to external elements, such as UV rays, as well as the dynamic nature of facial expression. Many cosmetic products and procedures provide global improvement to aging skin, whereas injectable therapies are frequently utilized to diminish specific, target wrinkles. Despite their broad availability, some patients are unwilling to undergo injectables and would benefit from an effective topical option. A noninvasive option to volumize target wrinkle areas could also extend benefits of commonly used cosmetic anti-aging products. To this end, a two-step formulation containing the novel, cosmetic anti-aging ingredient, N-acetyl tyrosinamide, was developed for use on targeted wrinkle areas. The tolerability and efficacy of the serum plus cream were tested for 16 weeks in women with moderate facial photodamage on predetermined wrinkle areas (glabellar lines, nasolabial folds, under eye lines, and lateral canthal (crow's feet) wrinkles) in a single-center, randomized, double-blind, vehicle-controlled, clinical trial. Seventy women (47 Active group, 23 Vehicle group) completed the study. Digital photography, clinical grading, ultrasound and self-assessment scores confirmed improvement to wrinkle areas. The topical cosmetic formulation was statistically superior (P<0.05) to its vehicle in visually improving nasolabial folds, glabellar lines, crow's feet, and under eye wrinkles and in reducing pinch recoil time. Both the test formulation and its vehicle were tolerated well. The novel, two-step cosmetic formulation reduced the appearance of wrinkles and increased skin elasticity thus providing an effective anti-aging option for target wrinkle areas. This study suggests that in addition to its use as monotherapy for reducing targeted lines and wrinkles this cosmetic formulation may be also serve as an adjuvant to injectable therapies.

[Radiotherapy volume delineation based on (18F)-fluorodeoxyglucose positron emission tomography for locally advanced or inoperable oesophageal cancer].

PubMed

Encaoua, J; Abgral, R; Leleu, C; El Kabbaj, O; Caradec, P; Bourhis, D; Pradier, O; Schick, U

2017-06-01

To study the impact on radiotherapy planning of an automatically segmented target volume delineation based on ( 18 F)-fluorodeoxy-D-glucose (FDG)-hybrid positron emission tomography-computed tomography (PET-CT) compared to a manually delineation based on computed tomography (CT) in oesophageal carcinoma patients. Fifty-eight patients diagnosed with oesophageal cancer between September 2009 and November 2014 were included. The majority had squamous cell carcinoma (84.5 %), and advanced stage (37.9 % were stade IIIA) and 44.8 % had middle oesophageal lesion. Gross tumour volumes were retrospectively defined based either manually on CT or automatically on coregistered PET/CT images using three different threshold methods: standard-uptake value (SUV) of 2.5, 40 % of maximum intensity and signal-to-background ratio. Target volumes were compared in length, volume and using the index of conformality. Radiotherapy plans to the dose of 50Gy and 66Gy using intensity-modulated radiotherapy were generated and compared for both data sets. Planification target volume coverage and doses delivered to organs at risk (heart, lung and spinal cord) were compared. The gross tumour volume based manually on CT was significantly longer than that automatically based on signal-to-background ratio (6.4cm versus 5.3cm; P<0.008). Doses to the lungs (V20, D mean ), heart (V40), and spinal cord (D max ) were significantly lower on plans using the PTV SBR . The PTV SBR coverage was statistically better than the PTV CT coverage on both plans. (50Gy: P<0.0004 and 66Gy: P<0.0006). The automatic PET segmentation algorithm based on the signal-to-background ratio method for the delineation of oesophageal tumours is interesting, and results in better target volume coverage and decreased dose to organs at risk. This may allow dose escalation up to 66Gy to the gross tumour volume. Copyright © 2017 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights

SU-E-J-226: Efficient Use of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) for Cervical-Cancer Brachytherapy

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

Damato, A; Bhagwat, M; Buzurovic, I

Purpose: To investigate image modality selection in an environment with limited access to interventional MRI for image-guided high-dose-rate cervical-cancer brachytherapy. Methods: Records of all cervical-cancer patients treated with brachytherapy between 1/2013 and 8/2014 were analyzed. Insertions were performed under CT guidance (CT group) or with >1 fraction under 3T MR guidance (MRI group; subMRI includes only patients who also had a CT-guided insertion). Differences between groups in clinical target volume (CTV), disease stage (I/II or III/IV), number of patients with or without interstitial needles, and CTV D90 were investigated. Statistical significance was evaluated with the Student T test and Fishermore » test (p <0.05). Results: 46 cervical-cancer patients were included (16 MRI [3 subMRI], 30 CT). CTV: overall, 55±53 cm3; MRI, 81±61 cm3; CT, 42±44 cm3 (p = 0.017). Stage: overall, 24 I/II and 22 III/IV; MRI, 3 I/II and 13 III/IV; CT, 21 I/II and 9 III/IV (p = 0.002). Use of needles: overall, 26 without and 20 with; MRI, 5 without and 11 with; CT, 21 without and 9 with (p = 0.015). CTV D90: overall, 82±5 Gy; MRI, 81±6 Gy; CT, 82±5 Gy (p = 0.78). SubMRI: CTV and D90 (as % of nominal fraction dose) were 23±6 cm3 and 124±3% for MRI-guided insertions and 21±5 cm3 (p = 0.83) and 106±12% (p = 0.15) for CT-guided insertions. Conclusion: Statistically significant differences in patient population indicate preferential use of MRI for patients with high-stage disease and large residual CTVs requiring the use of interstitial needles. CTV D90 was similar between groups, despite the difference in patient selection. For patients who underwent both CT and MRI insertions, a larger MR CTV D90 and similar CTVs between insertions were observed. While MRI is generally preferable to CT, MRI selection can be optimized in environments without a dedicated MRI brachytherapy suite. This work was partially funded by the NIH R21 CA167800 (PI: Viswanathan; aviswanathan@partners.org)« less

Diffusion and perfusion weighted magnetic resonance imaging for tumor volume definition in radiotherapy of brain tumors.

PubMed

Guo, Lu; Wang, Gang; Feng, Yuanming; Yu, Tonggang; Guo, Yu; Bai, Xu; Ye, Zhaoxiang

2016-09-21

Accurate target volume delineation is crucial for the radiotherapy of tumors. Diffusion and perfusion magnetic resonance imaging (MRI) can provide functional information about brain tumors, and they are able to detect tumor volume and physiological changes beyond the lesions shown on conventional MRI. This review examines recent studies that utilized diffusion and perfusion MRI for tumor volume definition in radiotherapy of brain tumors, and it presents the opportunities and challenges in the integration of multimodal functional MRI into clinical practice. The results indicate that specialized and robust post-processing algorithms and tools are needed for the precise alignment of targets on the images, and comprehensive validations with more clinical data are important for the improvement of the correlation between histopathologic results and MRI parameter images.

Residual tumor after neoadjuvant chemoradiation outside the radiation therapy target volume: a new prognostic factor for survival in esophageal cancer.

PubMed

Muijs, Christina; Smit, Justin; Karrenbeld, Arend; Beukema, Jannet; Mul, Veronique; van Dam, Go; Hospers, Geke; Kluin, Phillip; Langendijk, Johannes; Plukker, John

2014-03-15

The aim of this study was to analyze the accuracy of gross tumor volume (GTV) delineation and clinical target volume (CTV) margins for neoadjuvant chemoradiation therapy (neo-CRT) in esophageal carcinoma at pathologic examination and to determine the impact on survival. The study population consisted of 63 esophageal cancer patients treated with neo-CRT. GTV and CTV borders were demarcated in situ during surgery on the esophagus, using anatomical reference points to provide accurate information regarding tumor location at pathologic evaluation. To identify prognostic factors for disease-free survival (DFS) and overall survival (OS), a Cox regression analysis was performed. After resection, macroscopic residual tumor was found outside the GTV in 7 patients (11%). Microscopic residual tumor was located outside the CTV in 9 patients (14%). The median follow-up was 15.6 months. With multivariate analysis, only microscopic tumor outside the CTV (hazard ratio [HR], 4.96; 95% confidence interval [CI], 1.03-15.36), and perineural growth (HR, 5.77; 95% CI, 1.27-26.13) were identified as independent prognostic factors for OS. The 1-year OS was 20% for patients with tumor outside the CTV and 86% for those without (P<.01). For DFS, microscopic tumor outside the CTV (HR, 5.92; 95% CI, 1.89-18.54) and ypN+ (HR, 3.36; 95% CI, 1.33-8.48) were identified as independent adverse prognostic factors. The 1-year DFS was 23% versus 77% for patients with or without tumor outside the CTV (P<.01). Microscopic tumor outside the CTV is associated with markedly worse OS after neo-CRT. This may either stress the importance of accurate tumor delineation or reflect aggressive tumor behavior requiring new adjuvant treatment modalities. Copyright © 2014 Elsevier Inc. All rights reserved.

Analysis of radiation exposure for naval units of Operation Crossroads. Volume 3. (Appendix B) support ships. Technical report

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

Weitz, R.; Thomas, C.; Klemm, J.

1982-03-03

External radiation doses are reconstructed for crews of support and target ships of Joint Task Force One at Operation CROSSROADS, 1946. Volume I describes the reconstruction methodology, which consists of modeling the radiation environment, to include the radioactivity of lagoon water, target ships, and support ship contamination; retracing ship paths through this environment; and calculating the doses to shipboard personnel. The USS RECLAIMER, a support ship, is selected as a representative ship to demonstrate this methodology. Doses for all other ships are summarized. Volume II (Appendix A) details the results for target ship personnel. Volume III (Appendix B) details themore » results for support ship personnel. Calculated doses for more than 36,000 personnel aboard support ships while at Bikini range from zero to 1.7 rem. Of those approximately 34,000 are less than 0.5 rem. From the models provided, doses due to target ship reboarding and doses accrued after departure from Bikini can be calculated, based on the individual circumstances of exposure.« less

[4D-CT-based plan target volume (PTV) definition compared with conventional PTV definition using general margin in radiotherapy for lung cancer].

PubMed

Ju, Xiao; Li, Minghui; Zhou, Zongmei; Zhang, Ke; Han, Wei; Fu, Guishan; Cao, Ying; Wang, Lyuhua

2014-01-01

To investigate the dosimetric benefit of 4D-CT in the planning target volume (PTV) definition process compared with conventional PTV definition using general margin in radiotherapy of lung cancer. A set of 4D-CT images and multiphase helical CT scans were obtained in 10 patients with lung cancer. The radiotherapeutic plans based on PTV determined by 4D-CT and in addition of general margin were performed, respectively. The 3D motion of the centroid of GTV and the 3D spatial motion vectors were calculated. The differences of the two kinds of PTVs, mean lung dose (MLD), V5,V10,V15,V20 of total lung, mean heart dose (MHD), V30 and V40 of heart, D99 and D95 were compared, and the correlation between them and the 3D spatial motion vector was analyzed. The PTV4D in eight patients were smaller than PTVconv, with a mean reduction of (13.0 ± 8.0)% (P = 0.018). In other two patients, whose respiration motion was great, PTV4D was larger than PTVconv. The mean 3D spatial motion vector of GTV centroid was (0.78 ± 0.72)cm. By using 4D-CT, the mean reduction of MLD was (8.6 ± 9.9)% (P = 0.037). V5, V10, V15, V20 of total lung were decreased averagely by (7.2 ± 10.5)%, (5.5 ± 8.9)%, (6.5 ± 8.4)% and (5.7 ± 7.4)%, respectively (P < 0.05 for all). There was a significant positive correlation between PTV4D/PTVconv and the 3D spatial motion vector of the GTV centroid (P = 0.008). A significant inverse correlation was found between D994D/D99conv and the 3D spatial motion vector of the GTV centroid (P = 0.002). D994D/D99conv, (MLDconv-MLD4D) /MLDconv, total lung (V5conv-V54D)/V5conv, total lung (V10conv-V104D)/V10conv, (MHDconv-MHD4D)/MHDconv, heart (V30conv-V304D)/V30conv were inversely correlated with PTV4D/PTVconv (P < 0.05 for all). 4D-CT can be used to evaluate the respiration motion of lung tumor accurately. The 4D-CT-based PTV definition and radiotherapeutic planing can reduce the volume of PTV in patients with small respiration motion, increase the intra-target dose, and

Cone-Beam Computed Tomography–Guided Positioning of Laryngeal Cancer Patients with Large Interfraction Time Trends in Setup and Nonrigid Anatomy Variations

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

Gangsaas, Anne, E-mail: a.gangsaas@erasmusmc.nl; Astreinidou, Eleftheria; Quint, Sandra

2013-10-01

Purpose: To investigate interfraction setup variations of the primary tumor, elective nodes, and vertebrae in laryngeal cancer patients and to validate protocols for cone beam computed tomography (CBCT)-guided correction. Methods and Materials: For 30 patients, CBCT-measured displacements in fractionated treatments were used to investigate population setup errors and to simulate residual setup errors for the no action level (NAL) offline protocol, the extended NAL (eNAL) protocol, and daily CBCT acquisition with online analysis and repositioning. Results: Without corrections, 12 of 26 patients treated with radical radiation therapy would have experienced a gradual change (time trend) in primary tumor setup ≥4more » mm in the craniocaudal (CC) direction during the fractionated treatment (11/12 in caudal direction, maximum 11 mm). Due to these trends, correction of primary tumor displacements with NAL resulted in large residual CC errors (required margin 6.7 mm). With the weekly correction vector adjustments in eNAL, the trends could be largely compensated (CC margin 3.5 mm). Correlation between movements of the primary and nodal clinical target volumes (CTVs) in the CC direction was poor (r{sup 2}=0.15). Therefore, even with online setup corrections of the primary CTV, the required CC margin for the nodal CTV was as large as 6.8 mm. Also for the vertebrae, large time trends were observed for some patients. Because of poor CC correlation (r{sup 2}=0.19) between displacements of the primary CTV and the vertebrae, even with daily online repositioning of the vertebrae, the required CC margin around the primary CTV was 6.9 mm. Conclusions: Laryngeal cancer patients showed substantial interfraction setup variations, including large time trends, and poor CC correlation between primary tumor displacements and motion of the nodes and vertebrae (internal tumor motion). These trends and nonrigid anatomy variations have to be considered in the choice of setup verification

Comparing proton treatment plans of pediatric brain tumors in two pencil beam scanning nozzles with different spot sizes

PubMed Central

Kralik, John C.; Xi, Liwen; Solberg, Timothy D.; Simone, Charles B.

2015-01-01

Target coverage and organ‐at‐risk sparing were compared for 22 pediatric patients with primary brain tumors treated using two distinct nozzles in pencil beam scanning (PBS) proton therapy. Consecutive patients treated at our institution using a PBS‐dedicated nozzle (DN) were replanned using a universal nozzle (UN) beam model and the original DN plan objectives. Various cranial sites were treated among the patients to prescription doses ranging from 45 to 54 Gy. Organs at risk (OARs) evaluated were patient‐dependent; 15 unique OARs were analyzed, all of which were assessed in at least 10 patients. Clinical target volume (CTV) coverage and organ sparing were compared for the two nozzles using dose‐volume histogram data. Statistical analysis using a confidence‐interval approach demonstrates that CTV coverage is equivalent for UN and DN plans within ±5% equivalence bounds. In contrast, average mean and maximum doses are significantly higher for nearly all 15 OARs in the UN plans. The average median increase over all OARs and patients is approximately 1.7 Gy, with an increase in the 25%–75% of 1.0–2.3 Gy; the median increase to the pituitary gland, temporal lobes, eyes and cochleas are 1.8, 1.7, 0.7, and 2.7 Gy, respectively. The CTV dose distributions fall off slower for UN than for the DN plans; hence, normal tissue structures in close proximity to CTVs receive higher doses in UN plans than in DN plans. The higher OAR doses in the UN plans are likely due to the larger spot profile in plans created with UN beams. In light of the high rates of toxicities in pediatric patients receiving cranial irradiation and in light of selected brain tumor types having high cure rates, this study suggests the smaller DN beam profile is preferable for the advantage of reducing dose to OARs. PACS number: 87.55.D‐ PMID:26699553

[State of the art in fluid and volume therapy : A user-friendly staged concept].

PubMed

Rehm, M; Hulde, N; Kammerer, T; Meidert, A S; Hofmann-Kiefer, K

2017-03-01

Adequate fluid therapy is highly important for the perioperative outcome of our patients. Both, hypovolemia and hypervolemia can lead to an increase in perioperative complications and can impair the outcome. Therefore, perioperative infusion therapy should be target-oriented. The main target is to maintain the patient's preoperative normovolemia by using a sophisticated, rational infusion strategy.Perioperative fluid losses should be discriminated from volume losses (surgical blood loss or interstitial volume losses containing protein). Fluid losses as urine or perspiratio insensibilis (0.5-1.0 ml/kg/h) should be replaced by balanced crystalloids in a ratio of 1:1. Volume therapy step 1: Blood loss up to a maximum value of 20% of the patient's blood volume should be replaced by balanced crystalloids in a ratio of 4(-5):1. Volume therapy step 2: Higher blood losses should be treated by using iso-oncotic, preferential balanced colloids in a ratio of 1:1. For this purpose hydroxyethyl starch can also be used perioperatively if there is no respective contraindication, such as sepsis, burn injuries, critically ill patients, renal impairment or renal replacement therapy, and severe coagulopathy. Volume therapy step 3: If there is an indication for red cell concentrates or coagulation factors, a differentiated application of blood and blood products should be performed.

Anterior Insula Volume and Guilt

PubMed Central

Belden, Andy C.; Barch, Deanna M.; Oakberg, Timothy J.; April, Laura M.; Harms, Michael P.; Botteron, Kelly N.; Luby, Joan L.

2016-01-01

IMPORTANCE This is the first study to date to examine volumetric alterations in the anterior insula (AI) as a potential biomarker for the course of childhood major depressive disorder (MDD). OBJECTIVES To examine whether children with a history of preschool-onset (PO) MDD show reduced AI volume, whether a specific symptom of PO MDD (pathological guilt) is related to AI volume reduction (given the known relationship between AI and guilt processing), and whether AI volumes predict subsequent likelihood of having an episode of MDD. DESIGN, SETTING, AND PARTICIPANTS In a prospective longitudinal study, 306 children (age range, 3.00–5.11 years) and caregivers completed DSM diagnostic assessments at 6 annual time points during 10 years as part of the Preschool Depression Study. Magnetic resonance imaging was completed on a subset of 145 school-age children (age range, 6.11–12.11 years). MAIN OUTCOMES AND MEASURES Whole-brain–adjusted AI volume measured using magnetic resonance imaging at school age and children’s diagnosis of MDD any time after their imaging. RESULTS Compared with children without a history of PO MDD, school-age children previously diagnosed as having PO MDD had smaller left and right AI volumes (Wilks Λ = 0.94, F2,124 = 3.37, P = .04, Cohen d = 0.23). However, the effect of PO MDD on reduced AI volumes was better explained by children’s experience of pathological guilt during preschool (Λ = 0.91, F2,120 = 6.17, P = .003, d = .30). When covarying for children’s lifetime history of MDD episodes, their experience of pathological guilt during preschool, as well as their sex and age at the time of imaging, schoolchildren’s right-side AI volume was a significant predictor of being diagnosed as having an MDD episode after imaging (odds ratio, 0.96; 95% CI, 0.01–0.75; P = .03). CONCLUSIONS AND RELEVANCE These results provide evidence that structural abnormalities in AI volume are related to the neurobiology of depressive disorders starting in

Beam-specific planning volumes for scattered-proton lung radiotherapy

NASA Astrophysics Data System (ADS)

Flampouri, S.; Hoppe, B. S.; Slopsema, R. L.; Li, Z.

2014-08-01

This work describes the clinical implementation of a beam-specific planning treatment volume (bsPTV) calculation for lung cancer proton therapy and its integration into the treatment planning process. Uncertainties incorporated in the calculation of the bsPTV included setup errors, machine delivery variability, breathing effects, inherent proton range uncertainties and combinations of the above. Margins were added for translational and rotational setup errors and breathing motion variability during the course of treatment as well as for their effect on proton range of each treatment field. The effect of breathing motion and deformation on the proton range was calculated from 4D computed tomography data. Range uncertainties were considered taking into account the individual voxel HU uncertainty along each proton beamlet. Beam-specific treatment volumes generated for 12 patients were used: a) as planning targets, b) for routine plan evaluation, c) to aid beam angle selection and d) to create beam-specific margins for organs at risk to insure sparing. The alternative planning technique based on the bsPTVs produced similar target coverage as the conventional proton plans while better sparing the surrounding tissues. Conventional proton plans were evaluated by comparing the dose distributions per beam with the corresponding bsPTV. The bsPTV volume as a function of beam angle revealed some unexpected sources of uncertainty and could help the planner choose more robust beams. Beam-specific planning volume for the spinal cord was used for dose distribution shaping to ensure organ sparing laterally and distally to the beam.

Mapping of nodal disease in locally advanced prostate cancer: Rethinking the clinical target volume for pelvic nodal irradiation based on vascular rather than bony anatomy

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

Shih, Helen A.; Harisinghani, Mukesh; Zietman, Anthony L.

2005-11-15

Purpose: Toxicity from pelvic irradiation could be reduced if fields were limited to likely areas of nodal involvement rather than using the standard 'four-field box.' We employed a novel magnetic resonance lymphangiographic technique to highlight the likely sites of occult nodal metastasis from prostate cancer. Methods and Materials: Eighteen prostate cancer patients with pathologically confirmed node-positive disease had a total of 69 pathologic nodes identifiable by lymphotropic nanoparticle-enhanced MRI and semiquantitative nodal analysis. Fourteen of these nodes were in the para-aortic region, and 55 were in the pelvis. The position of each of these malignant nodes was mapped to amore » common template based on its relation to skeletal or vascular anatomy. Results: Relative to skeletal anatomy, nodes covered a diffuse volume from the mid lumbar spine to the superior pubic ramus and along the sacrum and pelvic side walls. In contrast, the nodal metastases mapped much more tightly relative to the large pelvic vessels. A proposed pelvic clinical target volume to encompass the region at greatest risk of containing occult nodal metastases would include a 2.0-cm radial expansion volume around the distal common iliac and proximal external and internal iliac vessels that would encompass 94.5% of the pelvic nodes at risk as defined by our node-positive prostate cancer patient cohort. Conclusions: Nodal metastases from prostate cancer are largely localized along the major pelvic vasculature. Defining nodal radiation treatment portals based on vascular rather than bony anatomy may allow for a significant decrease in normal pelvic tissue irradiation and its associated toxicities.« less

Validation of a reaction volume reduction protocol for analysis of Y chromosome haplotypes targeting DNA databases.

PubMed

Souza, C A; Oliveira, T C; Crovella, S; Santos, S M; Rabêlo, K C N; Soriano, E P; Carvalho, M V D; Junior, A F Caldas; Porto, G G; Campello, R I C; Antunes, A A; Queiroz, R A; Souza, S M

2017-04-28

The use of Y chromosome haplotypes, important for the detection of sexual crimes in forensics, has gained prominence with the use of databases that incorporate these genetic profiles in their system. Here, we optimized and validated an amplification protocol for Y chromosome profile retrieval in reference samples using lesser materials than those in commercial kits. FTA ® cards (Flinders Technology Associates) were used to support the oral cells of male individuals, which were amplified directly using the SwabSolution reagent (Promega). First, we optimized and validated the process to define the volume and cycling conditions. Three reference samples and nineteen 1.2 mm-diameter perforated discs were used per sample. Amplification of one or two discs (samples) with the PowerPlex ® Y23 kit (Promega) was performed using 25, 26, and 27 thermal cycles. Twenty percent, 32%, and 100% reagent volumes, one disc, and 26 cycles were used for the control per sample. Thereafter, all samples (N = 270) were amplified using 27 cycles, one disc, and 32% reagents (optimized conditions). Data was analyzed using a study of equilibrium values between fluorophore colors. In the samples analyzed with 20% volume, an imbalance was observed in peak heights, both inside and in-between each dye. In samples amplified with 32% reagents, the values obtained for the intra-color and inter-color standard balance calculations for verification of the quality of the analyzed peaks were similar to those of samples amplified with 100% of the recommended volume. The quality of the profiles obtained with 32% reagents was suitable for insertion into databases.

Planning Target Volume D95 and Mean Dose Should Be Considered for Optimal Local Control for Stereotactic Ablative Radiation Therapy

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

Zhao, Lina; Zhou, Shouhao; Balter, Peter

Purpose: To identify the optimal dose parameters predictive for local/lobar control after stereotactic ablative radiation therapy (SABR) in early-stage non-small cell lung cancer (NSCLC). Methods and Materials: This study encompassed a total of 1092 patients (1200 lesions) with NSCLC of clinical stage T1-T2 N0M0 who were treated with SABR of 50 Gy in 4 fractions or 70 Gy in 10 fractions, depending on tumor location/size, using computed tomography-based heterogeneity corrections and a convolution superposition calculation algorithm. Patients were monitored by chest CT or positron emission tomography/CT and/or biopsy after SABR. Factors predicting local/lobar recurrence (LR) were determined by competing risk multivariate analysis.more » Continuous variables were divided into 2 subgroups at cutoff values identified by receiver operating characteristic curves. Results: At a median follow-up time of 31.7 months (interquartile range, 14.8-51.3 months), the 5-year time to local recurrence within the same lobe and overall survival rates were 93.8% and 44.8%, respectively. Total cumulative number of patients experiencing LR was 40 (3.7%), occurring at a median time of 14.4 months (range, 4.8-46 months). Using multivariate competing risk analysis, independent predictive factors for LR after SABR were minimum biologically effective dose (BED{sub 10}) to 95% of planning target volume (PTVD95 BED{sub 10}) ≤86 Gy (corresponding to PTV D95 physics dose of 42 Gy in 4 fractions or 55 Gy in 10 fractions) and gross tumor volume ≥8.3 cm{sup 3}. The PTVmean BED{sub 10} was highly correlated with PTVD95 BED{sub 10.} In univariate analysis, a cutoff of 130 Gy for PTVmean BED{sub 10} (corresponding to PTVmean physics dose of 55 Gy in 4 fractions or 75 Gy in 10 fractions) was also significantly associated with LR. Conclusions: In addition to gross tumor volume, higher radiation dose delivered to the PTV predicts for better local/lobar control. We recommend that both PTVD

Portal imaging based definition of the planning target volume during pelvic irradiation for gynecological malignancies.

PubMed

Mock, U; Dieckmann, K; Wolff, U; Knocke, T H; Pötter, R

1999-08-01

Geometrical accuracy in patient positioning can vary substantially during external radiotherapy. This study estimated the set-up accuracy during pelvic irradiation for gynecological malignancies for determination of safety margins (planning target volume, PTV). Based on electronic portal imaging devices (EPID), 25 patients undergoing 4-field pelvic irradiation for gynecological malignancies were analyzed with regard to set-up accuracy during the treatment course. Regularly performed EPID images were used in order to systematically assess the systematic and random component of set-up displacements. Anatomical matching of verification and simulation images was followed by measuring corresponding distances between the central axis and anatomical features. Data analysis of set-up errors referred to the x-, y-,and z-axes. Additionally, cumulative frequencies were evaluated. A total of 50 simulation films and 313 verification images were analyzed. For the anterior-posterior (AP) beam direction mean deviations along the x- and z-axes were 1.5 mm and -1.9 mm, respectively. Moreover, random errors of 4.8 mm (x-axis) and 3.0 mm (z-axis) were determined. Concerning the latero-lateral treatment fields, the systematic errors along the two axes were calculated to 2.9 mm (y-axis) and -2.0 mm (z-axis) and random errors of 3.8 mm and 3.5 mm were found, respectively. The cumulative frequency of misalignments < or =5 mm showed values of 75% (AP fields) and 72% (latero-lateral fields). With regard to cumulative frequencies < or =10 mm quantification revealed values of 97% for both beam directions. During external pelvic irradiation therapy for gynecological malignancies, EPID images on a regular basis revealed acceptable set-up inaccuracies. Safety margins (PTV) of 1 cm appear to be sufficient, accounting for more than 95% of all deviations.

Effect of lung and target density on small-field dose coverage and PTV definition

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

Higgins, Patrick D., E-mail: higgi010@umn.edu; Ehler, Eric D.; Cho, Lawrence C.

We have studied the effect of target and lung density on block margin for small stereotactic body radiotherapy (SBRT) targets. A phantom (50 × 50 × 50 cm{sup 3}) was created in the Pinnacle (V9.2) planning system with a 23-cm diameter lung region of interest insert. Diameter targets of 1.6, 2.0, 3.0, and 4.0 cm were placed in the lung region of interest and centered at a physical depth of 15 cm. Target densities evaluated were 0.1 to 1.0 g/cm{sup 3}, whereas the surrounding lung density was varied between 0.05 and 0.6 g/cm{sup 3}. A dose of 100 cGy wasmore » delivered to the isocenter via a single 6-MV field, and the ratio of the average dose to points defining the lateral edges of the target to the isocenter dose was recorded for each combination. Field margins were varied from none to 1.5 cm in 0.25-cm steps. Data obtained in the phantom study were used to predict planning treatment volume (PTV) margins that would match the clinical PTV and isodose prescription for a clinical set of 39 SBRT cases. The average internal target volume (ITV) density was 0.73 ± 0.17, average local lung density was 0.33 ± 0.16, and average ITV diameter was 2.16 ± 0.8 cm. The phantom results initially underpredicted PTV margins by 0.35 cm. With this offset included in the model, the ratio of predicted-to-clinical PTVs was 1.05 ± 0.32. For a given target and lung density, it was found that treatment margin was insensitive to target diameter, except for the smallest (1.6-cm diameter) target, for which the treatment margin was more sensitive to density changes than the larger targets. We have developed a graphical relationship for block margin as a function of target and lung density, which should save time in the planning phase by shortening the design of PTV margins that can satisfy Radiation Therapy Oncology Group mandated treatment volume ratios.« less

Specific storage volumes: A useful tool for CO2 storage capacity assessment

USGS Publications Warehouse

Brennan, S.T.; Burruss, R.C.

2006-01-01

Subsurface geologic strata have the potential to store billions of tons of anthropogenic CO2; therefore, geologic carbon sequestration can be an effective mitigation tool used to slow the rate at which levels of atmospheric CO2 are increasing. Oil and gas reservoirs, coal beds, and saline reservoirs can be used for CO2 storage; however, it is difficult to assess and compare the relative storage capacities of these different settings. Typically, CO2 emissions are reported in units of mass, which are not directly applicable to comparing the CO2 storage capacities of the various storage targets. However, if the emission values are recalculated to volumes per unit mass (specific volume) then the volumes of geologic reservoirs necessary to store CO2 emissions from large point sources can be estimated. The factors necessary to convert the mass of CO2 emissions to geologic storage volume (referred to here as Specific Storage Volume or 'SSV') can be reported in units of cubic meters, cubic feet, and petroleum barrels. The SSVs can be used to estimate the reservoir volume needed to store CO2 produced over the lifetime of an individual point source, and to identify CO2 storage targets of sufficient size to meet the demand from that given point source. These storage volumes also can then be projected onto the land surface to outline a representative "footprint," which marks the areal extent of storage. This footprint can be compared with the terrestrial carbon sequestration capacity of the same land area. The overall utility of this application is that the total storage capacity of any given parcel of land (from surface to basement) can be determined, and may assist in making land management decisions. ?? Springer Science+Business Media, LLC 2006.

Disease Control After Reduced Volume Conformal and Intensity Modulated Radiation Therapy for Childhood Craniopharyngioma

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

Merchant, Thomas E., E-mail: thomas.merchant@stjude.org; Kun, Larry E.; Hua, Chia-Ho

2013-03-15

Purpose: To estimate the rate of disease control after conformal radiation therapy using reduced clinical target volume (CTV) margins and to determine factors that predict for tumor progression. Methods and Materials: Eighty-eight children (median age, 8.5 years; range, 3.2-17.6 years) received conformal or intensity modulated radiation therapy between 1998 and 2009. The study group included those prospectively treated from 1998 to 2003, using a 10-mm CTV, defined as the margin surrounding the solid and cystic tumor targeted to receive the prescription dose of 54 Gy. The CTV margin was subsequently reduced after 2003, yielding 2 groups of patients: those treatedmore » with a CTV margin greater than 5 mm (n=26) and those treated with a CTV margin less than or equal to 5 mm (n=62). Disease progression was estimated on the basis of additional variables including sex, race, extent of resection, tumor interventions, target volume margins, and frequency of weekly surveillance magnetic resonance (MR) imaging during radiation therapy. Median follow-up was 5 years. Results: There was no difference between progression-free survival rates based on CTV margins (>5 mm vs ≤5 mm) at 5 years (88.1% ± 6.3% vs 96.2% ± 4.4% [P=.6386]). There were no differences based on planning target volume (PTV) margins (or combined CTV plus PTV margins). The PTV was systematically reduced from 5 to 3 mm during the time period of the study. Factors predictive of superior progression-free survival included Caucasian race (P=.0175), no requirement for cerebrospinal fluid shunting (P=.0066), and number of surveillance imaging studies during treatment (P=.0216). Patients whose treatment protocol included a higher number of weekly surveillance MR imaging evaluations had a lower rate of tumor progression. Conclusions: These results suggest that targeted volume reductions for radiation therapy using smaller margins are feasible and safe but require careful monitoring. We are currently

Gated CT imaging using a free-breathing respiration signal from flow-volume spirometry

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

D'Souza, Warren D.; Kwok, Young; Deyoung, Chad

2005-12-15

Respiration-induced tumor motion is known to cause artifacts on free-breathing spiral CT images used in treatment planning. This leads to inaccurate delineation of target volumes on planning CT images. Flow-volume spirometry has been used previously for breath-holds during CT scans and radiation treatments using the active breathing control (ABC) system. We have developed a prototype by extending the flow-volume spirometer device to obtain gated CT scans using a PQ 5000 single-slice CT scanner. To test our prototype, we designed motion phantoms to compare image quality obtained with and without gated CT scan acquisition. Spiral and axial (nongated and gated) CTmore » scans were obtained of phantoms with motion periods of 3-5 s and amplitudes of 0.5-2 cm. Errors observed in the volume estimate of these structures were as much as 30% with moving phantoms during CT simulation. Application of motion-gated CT with active breathing control reduced these errors to within 5%. Motion-gated CT was then implemented in patients and the results are presented for two clinical cases: lung and abdomen. In each case, gated scans were acquired at end-inhalation, end-exhalation in addition to a conventional free-breathing (nongated) scan. The gated CT scans revealed reduced artifacts compared with the conventional free-breathing scan. Differences of up to 20% in the volume of the structures were observed between gated and free-breathing scans. A comparison of the overlap of structures between the gated and free-breathing scans revealed misalignment of the structures. These results demonstrate the ability of flow-volume spirometry to reduce errors in target volumes via gating during CT imaging.« less

SU-E-J-123: Assessing Segmentation Accuracy of Internal Volumes and Sub-Volumes in 4D PET/CT of Lung Tumors Using a Novel 3D Printed Phantom

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

Soultan, D; Murphy, J; James, C

2015-06-15

Purpose: To assess the accuracy of internal target volume (ITV) segmentation of lung tumors for treatment planning of simultaneous integrated boost (SIB) radiotherapy as seen in 4D PET/CT images, using a novel 3D-printed phantom. Methods: The insert mimics high PET tracer uptake in the core and 50% uptake in the periphery, by using a porous design at the periphery. A lung phantom with the insert was placed on a programmable moving platform. Seven breathing waveforms of ideal and patient-specific respiratory motion patterns were fed to the platform, and 4D PET/CT scans were acquired of each of them. CT images weremore » binned into 10 phases, and PET images were binned into 5 phases following the clinical protocol. Two scenarios were investigated for segmentation: a gate 30–70 window, and no gating. The radiation oncologist contoured the outer ITV of the porous insert with on CT images, while the internal void volume with 100% uptake was contoured on PET images for being indistinguishable from the outer volume in CT images. Segmented ITVs were compared to the expected volumes based on known target size and motion. Results: 3 ideal breathing patterns, 2 regular-breathing patient waveforms, and 2 irregular-breathing patient waveforms were used for this study. 18F-FDG was used as the PET tracer. The segmented ITVs from CT closely matched the expected motion for both no gating and gate 30–70 window, with disagreement of contoured ITV with respect to the expected volume not exceeding 13%. PET contours were seen to overestimate volumes in all the cases, up to more than 40%. Conclusion: 4DPET images of a novel 3D printed phantom designed to mimic different uptake values were obtained. 4DPET contours overestimated ITV volumes in all cases, while 4DCT contours matched expected ITV volume values. Investigation of the cause and effects of the discrepancies is undergoing.« less

SU-C-BRA-02: Gradient Based Method of Target Delineation On PET/MR Image of Head and Neck Cancer Patients

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

Dance, M; Chera, B; Falchook, A

2015-06-15

Purpose: Validate the consistency of a gradient-based segmentation tool to facilitate accurate delineation of PET/CT-based GTVs in head and neck cancers by comparing against hybrid PET/MR-derived GTV contours. Materials and Methods: A total of 18 head and neck target volumes (10 primary and 8 nodal) were retrospectively contoured using a gradient-based segmentation tool by two observers. Each observer independently contoured each target five times. Inter-observer variability was evaluated via absolute percent differences. Intra-observer variability was examined by percentage uncertainty. All target volumes were also contoured using the SUV percent threshold method. The thresholds were explored case by case so itsmore » derived volume matched with the gradient-based volume. Dice similarity coefficients (DSC) were calculated to determine overlap of PET/CT GTVs and PET/MR GTVs. Results: The Levene’s test showed there was no statistically significant difference of the variances between the observer’s gradient-derived contours. However, the absolute difference between the observer’s volumes was 10.83%, with a range from 0.39% up to 42.89%. PET-avid regions with qualitatively non-uniform shapes and intensity levels had a higher absolute percent difference near 25%, while regions with uniform shapes and intensity levels had an absolute percent difference of 2% between observers. The average percentage uncertainty between observers was 4.83% and 7%. As the volume of the gradient-derived contours increased, the SUV threshold percent needed to match the volume decreased. Dice coefficients showed good agreement of the PET/CT and PET/MR GTVs with an average DSC value across all volumes at 0.69. Conclusion: Gradient-based segmentation of PET volume showed good consistency in general but can vary considerably for non-uniform target shapes and intensity levels. PET/CT-derived GTV contours stemming from the gradient-based tool show good agreement with the anatomically and

Ambient temperature and volume of perihematomal edema in acute intracerebral haemorrhage: the INTERACT1 study.

PubMed

Zheng, Danni; Arima, Hisatomi; Heeley, Emma; Karpin, Anne; Yang, Jie; Chalmers, John; Anderson, Craig S

2015-01-01

As no human data exist, we aimed to determine the relation between ambient temperature and volume of perihematomal 'cerebral' edema in acute spontaneous intracerebral haemorrhage (ICH) among Chinese participants of the pilot phase, Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT1). INTERACT1 was a multicenter, open, blind outcome assessed, randomized controlled trial of intensive (systolic target <140 mmHg) vs. guideline-recommended (systolic target <180 mmHg) blood pressure (BP) lowering in 404 patients with acute ICH. Data on ambient temperature (mean, minimum, maximum, and range) on the day of each participant's ICH obtained from China Meteorological Data Sharing Service System were linked to other data including edema volumes. Multivariable regression analyses were performed to evaluate association between ambient temperature and edema volumes. A generalized linear regression model with a generalized estimating equations approach (GEE) was used to assess any association of ambient temperature and change in edema volume over 72 h. A total of 250 of all 384 Chinese participants had complete data that showed positive associations between ambient temperature (mean and minimum temperatures) and edema volumes at each time point over 72 h after hospital admission (all P < 0·05). All temperature parameters except diurnal temperature range were positively associated with edema volume after adjustment for confounding variables (all P < 0·02). An apparent positive association exists between ambient temperature and perihematomal edema volume in acute spontaneous ICH. © 2014 World Stroke Organization.

Rain Volume Estimation over Areas Using Satellite and Radar Data

NASA Technical Reports Server (NTRS)

Doneaud, A. A.; Miller, J. R., Jr.; Johnson, L. R.; Vonderhaar, T. H.; Laybe, P.

1984-01-01

The application of satellite data to a recently developed radar technique used to estimate convective rain volumes over areas on a dry environment (the northern Great Plains) is discussed. The area time integral technique (ATI) provides a means of estimating total rain volumes over fixed and floating target areas of the order of 1,000 to 100,000 km(2) for clusters lasting 40 min. The basis of the method is the existence of a strong correlation between the area coverage integrated over the lifetime of the storm (ATI) and the rain volume. One key element in this technique is that it does not require the consideration of the structure of the radar intensities inside the area coverage to generate rain volumes, but only considers the rain event per se. This fact might reduce or eliminate some sources of error in applying the technique to satellite data. The second key element is that the ATI once determined can be converted to total rain volume by using a constant factor (average rain rate) for a given locale.

An Analysis of Scalable GPU-Based Ray-Guided Volume Rendering

PubMed Central

Fogal, Thomas; Schiewe, Alexander; Krüger, Jens

2014-01-01

Volume rendering continues to be a critical method for analyzing large-scale scalar fields, in disciplines as diverse as biomedical engineering and computational fluid dynamics. Commodity desktop hardware has struggled to keep pace with data size increases, challenging modern visualization software to deliver responsive interactions for O(N3) algorithms such as volume rendering. We target the data type common in these domains: regularly-structured data. In this work, we demonstrate that the major limitation of most volume rendering approaches is their inability to switch the data sampling rate (and thus data size) quickly. Using a volume renderer inspired by recent work, we demonstrate that the actual amount of visualizable data for a scene is typically bound considerably lower than the memory available on a commodity GPU. Our instrumented renderer is used to investigate design decisions typically swept under the rug in volume rendering literature. The renderer is freely available, with binaries for all major platforms as well as full source code, to encourage reproduction and comparison with future research. PMID:25506079

18F-fluorodeoxyglucose positron emission tomography/computed tomography-based radiotherapy target volume definition in non-small-cell lung cancer: delineation by radiation oncologists vs. joint outlining with a PET radiologist?

PubMed

Hanna, Gerard G; Carson, Kathryn J; Lynch, Tom; McAleese, Jonathan; Cosgrove, Vivian P; Eakin, Ruth L; Stewart, David P; Zatari, Ashraf; O'Sullivan, Joe M; Hounsell, Alan R

2010-11-15

(18)F-Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) has benefits in target volume (TV) definition in radiotherapy treatment planning (RTP) for non-small-cell lung cancer (NSCLC); however, an optimal protocol for TV delineation has not been determined. We investigate volumetric and positional variation in gross tumor volume (GTV) delineation using a planning PET/CT among three radiation oncologists and a PET radiologist. RTP PET/CT scans were performed on 28 NSCLC patients (Stage IA-IIIB) of which 14 patients received prior induction chemotherapy. Three radiation oncologists and one PET radiologist working with a fourth radiation oncologist independently delineated the GTV on CT alone (GTV(CT)) and on fused PET/CT images (GTV(PETCT)). The mean percentage volume change (PVC) between GTV(CT) and GTV(PETCT) for the radiation oncologists and the PVC between GTV(CT) and GTV(PETCT) for the PET radiologist were compared using the Wilcoxon signed-rank test. Concordance index (CI) was used to assess both positional and volume change between GTV(CT) and GTV(PETCT) in a single measurement. For all patients, a significant difference in PVC from GTV(CT) to GTV(PETCT) exists between the radiation oncologist (median, 5.9%), and the PET radiologist (median, -0.4%, p = 0.001). However, no significant difference in median concordance index (comparing GTV(CT) and GTV(FUSED) for individual cases) was observed (PET radiologist = 0.73; radiation oncologists = 0.66; p = 0.088). Percentage volume changes from GTV(CT) to GTV(PETCT) were lower for the PET radiologist than for the radiation oncologists, suggesting a lower impact of PET/CT in TV delineation for the PET radiologist than for the oncologists. Guidelines are needed to standardize the use of PET/CT for TV delineation in RTP. Copyright © 2010 Elsevier Inc. All rights reserved.

Target Volume Delineation in Oropharyngeal Cancer: Impact of PET, MRI, and Physical Examination

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

Thiagarajan, Anuradha, E-mail: anu_thiagarajan@hotmail.com; Caria, Nicola; Schoeder, Heiko

2012-05-01

Introduction: Sole utilization of computed tomography (CT) scans in gross tumor volume (GTV) delineation for head-and-neck cancers is subject to inaccuracies. This study aims to evaluate contributions of magnetic resonance imaging (MRI), positron emission tomography (PET), and physical examination (PE) to GTV delineation in oropharyngeal cancer (OPC). Methods: Forty-one patients with OPC were studied. All underwent contrast-enhanced CT simulation scans (CECTs) that were registered with pretreatment PETs and MRIs. For each patient, three sets of primary and nodal GTV were contoured. First, reference GTVs (GTVref) were contoured by the treating radiation oncologist (RO) using CT, MRI, PET, and PE findings.more » Additional GTVs were created using fused CT/PET scans (GTVctpet) and CT/MRI scans (GTVctmr) by two other ROs blinded to GTVref. To compare GTVs, concordance indices (CI) were calculated by dividing the respective overlap volumes by overall volumes. To evaluate the contribution of PE, composite GTVs derived from CT, MRI, and PET (GTVctpetmr) were compared with GTVref. Results: For primary tumors, GTVref was significantly larger than GTVctpet and GTVctmr (p < 0.001). Although no significant difference in size was noted between GTVctpet and GTVctmr (p = 0.39), there was poor concordance between them (CI = 0.62). In addition, although CI (ctpetmr vs. ref) was low, it was significantly higher than CI (ctpet vs. ref) and CI (ctmr vs. ref) (p < 0.001), suggesting that neither modality should be used alone. Qualitative analyses to explain the low CI (ctpetmr vs. ref) revealed underestimation of mucosal disease when GTV was contoured without knowledge of PE findings. Similar trends were observed for nodal GTVs. However, CI (ctpet vs. ref), CI (ctmr vs. ref), and CI (ctpetmr vs. ref) were high (>0.75), indicating that although the modalities were complementary, the added benefit was small in the context of CECTs. In addition, PE did not aid greatly in nodal GTV

Microfluidic devices for the controlled manipulation of small volumes

DOEpatents

Ramsey, Michael J; Jacobson, Stephen C

2012-09-18

A method for conducting a broad range of biochemical analyses or manipulations on a series of nano- to subnanoliter reaction volumes and an apparatus for carrying out the same are disclosed. The invention is implemented on a fluidic microchip to provide high serial throughput. In particular, the disclosed device is a microfabricated channel device that can manipulate nanoliter or subnanoliter reaction volumes in a controlled manner to produce results at rates of 1 to 10 Hz per channel. The reaction volumes are manipulated in serial fashion analogous to a digital shift register. The invention has application to such problems as screening molecular or cellular targets using single beads from split-synthesis combinatorial libraries, screening single cells for RNA or protein expression, genetic diagnostic screening at the single cell level, or performing single cell signal transduction studies.

Microfluidic devices for the controlled manipulation of small volumes

DOEpatents

Ramsey, J Michael [Knoxville, TN; Jacobson, Stephen C [Knoxville, TN

2007-07-03

A method for conducting a broad range of biochemical analyses or manipulations on a series of nano- to subnanoliter reaction volumes and an apparatus for carrying out the same are disclosed. The invention is implemented on a fluidic microchip to provide high serial throughput. In particular, the disclosed device is a microfabricated channel device that can manipulate nanoliter or subnanoliter reaction volumes in a controlled manner to produce results at rates of 1 to 10 Hz per channel. The reaction volumes are manipulated in serial fashion analogous to a digital shift register. The invention has application to such problems as screening molecular or cellular targets using single beads from split-synthesis combinatorial libraries, screening single cells for RNA or protein expression, genetic diagnostic screening at the single cell level, or performing single cell signal transduction studies.

Regional Disparities in Online Map User Access Volume and Determining Factors

NASA Astrophysics Data System (ADS)

Li, R.; Yang, N.; Li, R.; Huang, W.; Wu, H.

2017-09-01

The regional disparities of online map user access volume (use `user access volume' in this paper to indicate briefly) is a topic of growing interest with the increment of popularity in public users, which helps to target the construction of geographic information services for different areas. At first place we statistically analysed the online map user access logs and quantified these regional access disparities on different scales. The results show that the volume of user access is decreasing from east to the west in China as a whole, while East China produces the most access volume; these cities are also the crucial economic and transport centres. Then Principal Component Regression (PCR) is applied to explore the regional disparities of user access volume. A determining model for Online Map access volume is proposed afterwards, which indicates that area scale is the primary determining factor for regional disparities, followed by public transport development level and public service development level. Other factors like user quality index and financial index have very limited influence on the user access volume. According to the study of regional disparities in user access volume, map providers can reasonably dispatch and allocate the data resources and service resources in each area and improve the operational efficiency of the Online Map server cluster.

MRI to delineate the gross tumor volume of nasopharyngeal cancers: which sequences and planes should be used?

PubMed

Popovtzer, Aron; Ibrahim, Mohannad; Tatro, Daniel; Feng, Felix Y; Ten Haken, Randall K; Eisbruch, Avraham

2014-09-01

Magnetic resonance imaging (MRI) has been found to be better than computed tomography for defining the extent of primary gross tumor volume (GTV) in advanced nasopharyngeal cancer. It is routinely applied for target delineation in planning radiotherapy. However, the specific MRI sequences/planes that should be used are unknown. Twelve patients with nasopharyngeal cancer underwent primary GTV evaluation with gadolinium-enhanced axial T1 weighted image (T1) and T2 weighted image (T2), coronal T1, and sagittal T1 sequences. Each sequence was registered with the planning computed tomography scans. Planning target volumes (PTVs) were derived by uniform expansions of the GTVs. The volumes encompassed by the various sequences/planes, and the volumes common to all sequences/planes, were compared quantitatively and anatomically to the volume delineated by the commonly used axial T1-based dataset. Addition of the axial T2 sequence increased the axial T1-based GTV by 12% on average (p = 0.004), and composite evaluations that included the coronal T1 and sagittal T1 planes increased the axial T1-based GTVs by 30% on average (p = 0.003). The axial T1-based PTVs were increased by 20% by the additional sequences (p = 0.04). Each sequence/plane added unique volume extensions. The GTVs common to all the T1 planes accounted for 38% of the total volumes of all the T1 planes. Anatomically, addition of the coronal and sagittal-based GTVs extended the axial T1-based GTV caudally and cranially, notably to the base of the skull. Adding MRI planes and sequences to the traditional axial T1 sequence yields significant quantitative and anatomically important extensions of the GTVs and PTVs. For accurate target delineation in nasopharyngeal cancer, we recommend that GTVs be outlined in all MRI sequences/planes and registered with the planning computed tomography scans.

SU-G-JeP3-09: Tumor Location Prediction Using Natural Respiratory Volume for Respiratory Gated Radiation Therapy (RGRT): System Verification Study

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

Kim, M; Jung, J; Yoon, D

Purpose: Respiratory gated radiation therapy (RGRT) gives accurate results when a patient’s breathing is stable and regular. Thus, the patient should be fully aware during respiratory pattern training before undergoing the RGRT treatment. In order to bypass the process of respiratory pattern training, we propose a target location prediction system for RGRT that uses only natural respiratory volume, and confirm its application. Methods: In order to verify the proposed target location prediction system, an in-house phantom set was used. This set involves a chest phantom including target, external markers, and motion generator. Natural respiratory volume signals were generated using themore » random function in MATLAB code. In the chest phantom, the target takes a linear motion based on the respiratory signal. After a four-dimensional computed tomography (4DCT) scan of the in-house phantom, the motion trajectory was derived as a linear equation. The accuracy of the linear equation was compared with that of the motion algorithm used by the operating motion generator. In addition, we attempted target location prediction using random respiratory volume values. Results: The correspondence rate of the linear equation derived from the 4DCT images with the motion algorithm of the motion generator was 99.41%. In addition, the average error rate of target location prediction was 1.23% for 26 cases. Conclusion: We confirmed the applicability of our proposed target location prediction system for RGRT using natural respiratory volume. If additional clinical studies can be conducted, a more accurate prediction system can be realized without requiring respiratory pattern training.« less

Perioperative patient safety indicators and hospital surgical volumes.

PubMed

Kitazawa, Takefumi; Matsumoto, Kunichika; Fujita, Shigeru; Yoshida, Ai; Iida, Shuhei; Nishizawa, Hirotoshi; Hasegawa, Tomonori

2014-02-28

Since the late 1990s, patient safety has been an important policy issue in developed countries. To evaluate the effectiveness of the activities of patient safety, it is necessary to quantitatively assess the incidence of adverse events by types of failure mode using tangible data. The purpose of this study is to calculate patient safety indicators (PSIs) using the Japanese Diagnosis Procedure Combination/per-diem payment system (DPC/PDPS) reimbursement data and to elucidate the relationship between perioperative PSIs and hospital surgical volume. DPC/PDPS data of the Medi-Target project managed by the All Japan Hospital Association were used. An observational study was conducted where PSIs were calculated using an algorithm proposed by the US Agency for Healthcare Research and Quality. We analyzed data of 1,383,872 patients from 188 hospitals who were discharged from January 2008 to December 2010. Among 20 provider level PSIs, four PSIs (three perioperative PSIs and decubitus ulcer) and mortality rates of postoperative patients were related to surgical volume. Low-volume hospitals (less than 33rd percentiles surgical volume per month) had higher mortality rates (5.7%, 95% confidence interval (CI), 3.9% to 7.4%) than mid- (2.9%, 95% CI, 2.6% to 3.3%) or high-volume hospitals (2.7%, 95% CI, 2.5% to 2.9%). Low-volume hospitals had more deaths among surgical inpatients with serious treatable complications (38.5%, 95% CI, 33.7% to 43.2%) than high-volume hospitals (21.4%, 95% CI, 19.0% to 23.9%). Also Low-volume hospitals had lower proportion of difficult surgeries (54.9%, 95% CI, 50.1% to 59.8%) compared with high-volume hospitals (63.4%, 95% CI, 62.3% to 64.6%). In low-volume hospitals, limited experience may have led to insufficient care for postoperative complications. We demonstrated that PSIs can be calculated using DPC/PDPS data and perioperative PSIs were related to hospital surgical volume. Further investigations focusing on identifying risk factors for poor

Radiotherapy Dose-Volume Effects on Salivary Gland Function

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

Deasy, Joseph O., E-mail: jdeasy@radonc.wustl.ed; Moiseenko, Vitali; Marks, Lawrence

2010-03-01

Publications relating parotid dose-volume characteristics to radiotherapy-induced salivary toxicity were reviewed. Late salivary dysfunction has been correlated to the mean parotid gland dose, with recovery occurring with time. Severe xerostomia (defined as long-term salivary function of <25% of baseline) is usually avoided if at least one parotid gland is spared to a mean dose of less than {approx}20 Gy or if both glands are spared to less than {approx}25 Gy (mean dose). For complex, partial-volume RT patterns (e.g., intensity-modulated radiotherapy), each parotid mean dose should be kept as low as possible, consistent with the desired clinical target volume coverage. Amore » lower parotid mean dose usually results in better function. Submandibular gland sparing also significantly decreases the risk of xerostomia. The currently available predictive models are imprecise, and additional study is required to identify more accurate models of xerostomia risk.« less

Automatic detection of sweep-meshable volumes

DOEpatents

Tautges,; Timothy J. , White; David, R [Pittsburgh, PA

2006-05-23

A method of and software for automatically determining whether a mesh can be generated by sweeping for a representation of a geometric solid comprising: classifying surface mesh schemes for surfaces of the representation locally using surface vertex types; grouping mappable and submappable surfaces of the representation into chains; computing volume edge types for the representation; recursively traversing surfaces of the representation and grouping the surfaces into source, target, and linking surface lists; and checking traversal direction when traversing onto linking surfaces.

Feasibility and Initial Dosimetric Findings for a Randomized Trial Using Dose-Painted Multiparametric Magnetic Resonance Imaging–Defined Targets in Prostate Cancer

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

Bossart, Elizabeth L., E-mail: EBossart@med.miami.edu; Stoyanova, Radka; Sandler, Kiri

2016-06-01

Purpose: To compare dosimetric characteristics with multiparametric magnetic resonance imaging–identified imaging tumor volume (gross tumor volume, GTV), prostate clinical target volume and planning target volume, and organs at risk (OARs) for 2 treatment techniques representing 2 arms of an institutional phase 3 randomized trial of hypofractionated external beam image guided highly targeted radiation therapy. Methods and Materials: Group 1 (n=20) patients were treated before the trial inception with the standard dose prescription. Each patient had an additional treatment plan generated per the experimental arm. A total of 40 treatment plans were compared (20 plans for each technique). Group 2 (n=15)more » consists of patients currently accrued to the hypofractionated external beam image guided highly targeted radiation therapy trial. Plans were created as per the treatment arm, with additional plans for 5 of the group 2 experimental arm with a 3-mm expansion in the imaging GTV. Results: For all plans in both patient groups, planning target volume coverage ranged from 95% to 100%; GTV coverage of 89.3 Gy for the experimental treatment plans ranged from 95.2% to 99.8%. For both groups 1 and 2, the percent volumes of rectum/anus and bladder receiving 40 Gy, 65 Gy, and 80 Gy were smaller in the experimental plans than in the standard plans. The percent volume at 1 Gy per fraction and 1.625 Gy per fraction were compared between the standard and the experimental arms, and these were found to be equivalent. Conclusions: The dose per fraction to the OARs can be made equal even when giving a large simultaneous integrated boost to the GTV. The data suggest that a GTV margin may be added without significant dose effects on the OARs.« less

Effects of breathing variation on gating window internal target volume in respiratory gated radiation therapy

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

Cai Jing; McLawhorn, Robert; Read, Paul W.

Purpose: To investigate the effects of breathing variation on gating window internal target volume (ITV{sub GW}) in respiratory gated radiation therapy. Method and Materials: Two-dimensional dynamic MRI (dMRI) of lung motion was acquired in ten volunteers and eight lung cancer patients. Resorted dMRI using 4DCT acquisition method (RedCAM) was generated for selected subjects by simulating the image rebinning process. A dynamic software generated phantom (dSGP) was created by moving a solid circle (to mimic the ''tumor'') with dMRI-determined motion trajectories. The gating window internal target area (ITA{sub GW}, 2D counterpart of ITV{sub GW}) was determined from both RedCAM and dSGP/dMRI.more » Its area (A), major axis (L1), minor axis (L2), and similarity (S) were calculated and compared. Results: In the phantom study of 3 cm tumor, measurements of the ITA{sub GW} from dSGP (A=10.0{+-}1.3 cm{sup 2}, L1=3.8{+-}0.4 cm, and L2=3.3{+-}0.1 cm) are significantly (p<0.001) greater than those from RedCAM (A=8.5{+-}0.7 cm{sup 2}, L1=3.5{+-}0.2 cm, and L2=3.1{+-}0.1 cm). Similarly, the differences are significantly greater (p<0.001) for the 1 cm tumor (A=1.9{+-}0.5 cm{sup 2}, L1=1.9{+-}0.4 cm, and L2=1.3{+-}0.1 cm in dSGP; A=1.3{+-}0.1 cm{sup 2}, L1=1.5{+-}0.2 cm, and L2=1.1{+-}0.1 cm in RedCAM). In patient studies, measurements of the ITA{sub GW} from dMRI (A=15.5{+-}8.2 cm{sup 2}, L1=5.0{+-}1.1 cm, and L2=3.8{+-}1.2 cm) are also significantly greater (p<0.05) than those from RedCAM (A=13.2{+-}8.5 cm{sup 2}, L1=4.3{+-}1.4 cm, and L2=3.7{+-}1.2 cm). Similarities were 0.9{+-}0.1, 0.8{+-}0.1, and 0.8{+-}0.1 in the 3 cm tumor phantom, 1 cm tumor phantom, and patient studies, respectively. Conclusion: ITV{sub GW} can be underestimated by 4DCT due to breathing variations. An additional margin may be needed to account for this potential error in generating a PTV{sub GW}. Cautions need to be taken when generating ITV{sub GW} from 4DCT in respiratory gated radiation therapy

Hypervelocity Impact (HVI). Volume 1; General Introduction

NASA Technical Reports Server (NTRS)

Gorman, Michael R.; Ziola, Steven M.

2007-01-01

During 2003 and 2004, the Johnson Space Center's White Sands Testing Facility in Las Cruces, New Mexico conducted hypervelocity impact tests on the space shuttle wing leading edge. Hypervelocity impact tests were conducted to determine if Micro-Meteoroid/Orbital Debris impacts could be reliably detected and located using simple passive ultrasonic methods. This volume contains an executive summary, overview of the method, brief descriptions of all targets, and highlights of results and conclusions.

Combining 3d Volume and Mesh Models for Representing Complicated Heritage Buildings

NASA Astrophysics Data System (ADS)

Tsai, F.; Chang, H.; Lin, Y.-W.

2017-08-01

This study developed a simple but effective strategy to combine 3D volume and mesh models for representing complicated heritage buildings and structures. The idea is to seamlessly integrate 3D parametric or polyhedral models and mesh-based digital surfaces to generate a hybrid 3D model that can take advantages of both modeling methods. The proposed hybrid model generation framework is separated into three phases. Firstly, after acquiring or generating 3D point clouds of the target, these 3D points are partitioned into different groups. Secondly, a parametric or polyhedral model of each group is generated based on plane and surface fitting algorithms to represent the basic structure of that region. A "bare-bones" model of the target can subsequently be constructed by connecting all 3D volume element models. In the third phase, the constructed bare-bones model is used as a mask to remove points enclosed by the bare-bones model from the original point clouds. The remaining points are then connected to form 3D surface mesh patches. The boundary points of each surface patch are identified and these boundary points are projected onto the surfaces of the bare-bones model. Finally, new meshes are created to connect the projected points and original mesh boundaries to integrate the mesh surfaces with the 3D volume model. The proposed method was applied to an open-source point cloud data set and point clouds of a local historical structure. Preliminary results indicated that the reconstructed hybrid models using the proposed method can retain both fundamental 3D volume characteristics and accurate geometric appearance with fine details. The reconstructed hybrid models can also be used to represent targets in different levels of detail according to user and system requirements in different applications.

A novel method for the evaluation of uncertainty in dose-volume histogram computation.

PubMed

Henríquez, Francisco Cutanda; Castrillón, Silvia Vargas

2008-03-15

Dose-volume histograms (DVHs) are a useful tool in state-of-the-art radiotherapy treatment planning, and it is essential to recognize their limitations. Even after a specific dose-calculation model is optimized, dose distributions computed by using treatment-planning systems are affected by several sources of uncertainty, such as algorithm limitations, measurement uncertainty in the data used to model the beam, and residual differences between measured and computed dose. This report presents a novel method to take them into account. To take into account the effect of associated uncertainties, a probabilistic approach using a new kind of histogram, a dose-expected volume histogram, is introduced. The expected value of the volume in the region of interest receiving an absorbed dose equal to or greater than a certain value is found by using the probability distribution of the dose at each point. A rectangular probability distribution is assumed for this point dose, and a formulation that accounts for uncertainties associated with point dose is presented for practical computations. This method is applied to a set of DVHs for different regions of interest, including 6 brain patients, 8 lung patients, 8 pelvis patients, and 6 prostate patients planned for intensity-modulated radiation therapy. Results show a greater effect on planning target volume coverage than in organs at risk. In cases of steep DVH gradients, such as planning target volumes, this new method shows the largest differences with the corresponding DVH; thus, the effect of the uncertainty is larger.

Chloride channels as drug targets

PubMed Central

Verkman, Alan S.; Galietta, Luis J. V.

2013-01-01

Chloride channels represent a relatively under-explored target class for drug discovery as elucidation of their identity and physiological roles has lagged behind that of many other drug targets. Chloride channels are involved in a wide range of biological functions, including epithelial fluid secretion, cell-volume regulation, neuroexcitation, smooth-muscle contraction and acidification of intracellular organelles. Mutations in several chloride channels cause human diseases, including cystic fibrosis, macular degeneration, myotonia, kidney stones, renal salt wasting and hyperekplexia. Chloride-channel modulators have potential applications in the treatment of some of these disorders, as well as in secretory diarrhoeas, polycystic kidney disease, osteoporosis and hypertension. Modulators of GABAA (γ-aminobutyric acid A) receptor chloride channels are in clinical use and several small-molecule chloride-channel modulators are in preclinical development and clinical trials. Here, we discuss the broad opportunities that remain in chloride-channel-based drug discovery. PMID:19153558

Maximum static inspiratory and expiratory pressures with different lung volumes

PubMed Central

Lausted, Christopher G; Johnson, Arthur T; Scott, William H; Johnson, Monique M; Coyne, Karen M; Coursey, Derya C

2006-01-01

Background Maximum pressures developed by the respiratory muscles can indicate the health of the respiratory system, help to determine maximum respiratory flow rates, and contribute to respiratory power development. Past measurements of maximum pressures have been found to be inadequate for inclusion in some exercise models involving respiration. Methods Maximum inspiratory and expiratory airway pressures were measured over a range of lung volumes in 29 female and 19 male adults. A commercial bell spirometry system was programmed to occlude airflow at nine target lung volumes ranging from 10% to 90% of vital capacity. Results In women, maximum expiratory pressure increased with volume from 39 to 61 cmH2O and maximum inspiratory pressure decreased with volume from 66 to 28 cmH2O. In men, maximum expiratory pressure increased with volume from 63 to 97 cmH2O and maximum inspiratory pressure decreased with volume from 97 to 39 cmH2O. Equations describing pressures for both sexes are: Pe/Pmax = 0.1426 Ln( %VC) + 0.3402 R2 = 0.95 Pi/Pmax = 0.234 Ln(100 - %VC) - 0.0828 R2 = 0.96 Conclusion These results were found to be consistent with values and trends obtained by other authors. Regression equations may be suitable for respiratory mechanics models. PMID:16677384

Communications strategies on alcohol and highway safety. Volume 2, High school youth

DOT National Transportation Integrated Search

1975-02-01

The study is in two volumes, the first dealing with adults aged 18-55, the second with high school youth. Both identify target populations and communications strategies for encouraging personal action steps to prevent drunk driving. One fourth of hig...

Communications strategies on alcohol and highway safety. Volume 1, Adults 18-55

DOT National Transportation Integrated Search

1975-02-01

The study is in two volumes, the first dealing with adults aged 18-55, the second with high school youth. Both identify target populations and communications strategies for encouraging personal action steps to prevent drunk driving. Fully 54% of adul...

A method for deriving a 4D-interpolated balanced planning target for mobile tumor radiotherapy.

PubMed

Roland, Teboh; Hales, Russell; McNutt, Todd; Wong, John; Simari, Patricio; Tryggestad, Erik

2012-01-01

Tumor control and normal tissue toxicity are strongly correlated to the tumor and normal tissue volumes receiving high prescribed dose levels in the course of radiotherapy. Planning target definition is, therefore, crucial to ensure favorable clinical outcomes. This is especially important for stereotactic body radiation therapy of lung cancers, characterized by high fractional doses and steep dose gradients. The shift in recent years from population-based to patient-specific treatment margins, as facilitated by the emergence of 4D medical imaging capabilities, is a major improvement. The commonly used motion-encompassing, or internal-target volume (ITV), target definition approach provides a high likelihood of coverage for the mobile tumor but inevitably exposes healthy tissue to high prescribed dose levels. The goal of this work was to generate an interpolated balanced planning target that takes into account both tumor coverage and normal tissue sparing from high prescribed dose levels, thereby improving on the ITV approach. For each 4DCT dataset, 4D deformable image registration was used to derive two bounding targets, namely, a 4D-intersection and a 4D-composite target which minimized normal tissue exposure to high prescribed dose levels and maximized tumor coverage, respectively. Through definition of an "effective overlap volume histogram" the authors derived an "interpolated balanced planning target" intended to balance normal tissue sparing from prescribed doses with tumor coverage. To demonstrate the dosimetric efficacy of the interpolated balanced planning target, the authors performed 4D treatment planning based on deformable image registration of 4D-CT data for five previously treated lung cancer patients. Two 4D plans were generated per patient, one based on the interpolated balanced planning target and the other based on the conventional ITV target. Plans were compared for tumor coverage and the degree of normal tissue sparing resulting from the new

Optoacoustic imaging of gold nanoparticles targeted to breast cancer cells

NASA Astrophysics Data System (ADS)

Eghtedari, Mohammad; Motamedi, Massoud; Popov, Vsevolod L.; Kotov, Nicholas A.; Oraevsky, Alexander A.

2004-07-01

Optoacoustic Tomography (OAT) is a rapidly growing technology that enables noninvasive deep imaging of biological tissues based on their light absorption. In OAT, the interaction of a pulsed laser with tissue increases the temperature of the absorbing components in a confined volume of tissue. Rapid perturbation of the temperature (<1°C) deep within tissue produces weak acoustic waves that easily travel to the surface of the tissue with minor attenuation. Abnormal angiogenesis in a malignant tumor, that increases its blood content, makes a native contrast for optoacoustic imaging; however, the application of OAT for early detection of malignant tumors requires the enhancement of optoacoustic signals originated from tumor by using an exogenous contrast agent. Due to their strong absorption, we have used gold nanoparticles (NP) as a contrast agent. 40nm spherical gold nanoparticles were attached to monoclonal antibody to target cell surface of breast cancer cells. The targeted cancer cells were implanted at depth of 5-6cm within a gelatinous object that optically resembles human breast. Experimental sensitivity measurements along with theoretical analysis showed that our optoacoustic imaging system is capable of detecting a phantom breast tumor with the volume of 0.15ml, which is composed of 25 million NP-targeted cancer cells, at a depth of 5 centimeters in vitro.

Polarimetric LIDAR with FRI sampling for target characterization

NASA Astrophysics Data System (ADS)

Wijerathna, Erandi; Creusere, Charles D.; Voelz, David; Castorena, Juan

2017-09-01

Polarimetric LIDAR is a significant tool for current remote sensing applications. In addition, measurement of the full waveform of the LIDAR echo provides improved ranging and target discrimination, although, data storage volume in this approach can be problematic. In the work presented here, we investigated the practical issues related to the implementation of a full waveform LIDAR system to identify polarization characteristics of multiple targets within the footprint of the illumination beam. This work was carried out on a laboratory LIDAR testbed that features a flexible arrangement of targets and the ability to change the target polarization characteristics. Targets with different retardance characteristics were illuminated with a linearly polarized laser beam and the return pulse intensities were analyzed by rotating a linear analyzer polarizer in front of a high-speed detector. Additionally, we explored the applicability and the limitations of applying a sparse sampling approach based on Finite Rate of Innovations (FRI) to compress and recover the characteristic parameters of the pulses reflected from the targets. The pulse parameter values extracted by the FRI analysis were accurate and we successfully distinguished the polarimetric characteristics and the range of multiple targets at different depths within the same beam footprint. We also demonstrated the recovery of an unknown target retardance value from the echoes by applying a Mueller matrix system model.

A dimensionless dynamic contrast enhanced MRI parameter for intra-prostatic tumour target volume delineation: initial comparison with histology

NASA Astrophysics Data System (ADS)

Hrinivich, W. Thomas; Gibson, Eli; Gaed, Mena; Gomez, Jose A.; Moussa, Madeleine; McKenzie, Charles A.; Bauman, Glenn S.; Ward, Aaron D.; Fenster, Aaron; Wong, Eugene

2014-03-01

Purpose: T2 weighted and diffusion weighted magnetic resonance imaging (MRI) show promise in isolating prostate tumours. Dynamic contrast enhanced (DCE)-MRI has also been employed as a component in multi-parametric tumour detection schemes. Model-based parameters such as Ktrans are conventionally used to characterize DCE images and require arterial contrast agent (CR) concentration. A robust parameter map that does not depend on arterial input may be more useful for target volume delineation. We present a dimensionless parameter (Wio) that characterizes CR wash-in and washout rates without requiring arterial CR concentration. Wio is compared to Ktrans in terms of ability to discriminate cancer in the prostate, as demonstrated via comparison with histology. Methods: Three subjects underwent DCE-MRI using gadolinium contrast and 7 s imaging temporal resolution. A pathologist identified cancer on whole-mount histology specimens, and slides were deformably registered to MR images. The ability of Wio maps to discriminate cancer was determined through receiver operating characteristic curve (ROC) analysis. Results: There is a trend that Wio shows greater area under the ROC curve (AUC) than Ktrans with median AUC values of 0.74 and 0.69 respectively, but the difference was not statistically significant based on a Wilcoxon signed-rank test (p = 0.13). Conclusions: Preliminary results indicate that Wio shows potential as a tool for Ktrans QA, showing similar ability to discriminate cancer in the prostate as Ktrans without requiring arterial CR concentration.

Calculation of the Frequency Distribution of the Energy Deposition in DNA Volumes by Heavy Ions

NASA Technical Reports Server (NTRS)

Plante, Ianik; Cicinotta, Francis A.

2012-01-01

Radiation quality effects are largely determined by energy deposition in small volumes of characteristic sizes less than 10 nm representative of short-segments of DNA, the DNA nucleosome, or molecules initiating oxidative stress in the nucleus, mitochondria, or extra-cellular matrix. On this scale, qualitatively distinct types of molecular damage are possible for high linear energy transfer (LET) radiation such as heavy ions compared to low LET radiation. Unique types of DNA lesions or oxidative damages are the likely outcome of the energy deposition. The frequency distribution for energy imparted to 1-20 nm targets per unit dose or particle fluence is a useful descriptor and can be evaluated as a function of impact parameter from an ions track. In this work, the simulation of 1-Gy irradiation of a cubic volume of 5 micron by: 1) 450 (1)H(+) ions, 300 MeV; 2) 10 (12)C(6+) ions, 290 MeV/amu and 3) (56)Fe(26+) ions, 1000 MeV/amu was done with the Monte-Carlo simulation code RITRACKS. Cylindrical targets are generated in the irradiated volume, with random orientation. The frequency distribution curves of the energy deposited in the targets is obtained. For small targets (i.e. <25 nm size), the probability of an ion to hit a target is very small; therefore a large number of tracks and targets as well as a large number of histories are necessary to obtain statistically significant results. This simulation is very time-consuming and is difficult to perform by using the original version of RITRACKS. Consequently, the code RITRACKS was adapted to use multiple CPU on a workstation or on a computer cluster. To validate the simulation results, similar calculations were performed using targets with fixed position and orientation, for which experimental data are available [5]. Since the probability of single- and double-strand breaks in DNA as function of energy deposited is well know, the results that were obtained can be used to estimate the yield of DSB, and can be extended

Bronchoscopic Thermal Vapor Ablation: Best Practice Recommendations from an Expert Panel on Endoscopic Lung Volume Reduction.

PubMed

Gompelmann, Daniela; Shah, Pallav L; Valipour, Arschang; Herth, Felix J F

2018-06-12

Bronchoscopic thermal vapor ablation (BTVA) represents one of the endoscopic lung volume reduction (ELVR) techniques that aims at hyperinflation reduction in patients with advanced emphysema to improve respiratory mechanics. By targeted segmental vapor ablation, an inflammatory response leads to tissue and volume reduction of the most diseased emphysematous segments. So far, BTVA has been demonstrated in several single-arm trials and 1 multinational randomized controlled trial to improve lung function, exercise capacity, and quality of life in patients with upper lobe-predominant emphysema irrespective of the collateral ventilation. In this review, we emphasize the practical aspects of this ELVR method. Patients with upper lobe-predominant emphysema, forced expiratory volume in 1 second (FEV1) between 20 and 45% of predicted, residual volume (RV) > 175% of predicted, and carbon monoxide diffusing capacity (DLCO) ≥20% of predicted can be considered for BTVA treatment. Prior to the procedure, a special software assists in identifying the target segments with the highest emphysema index, volume and the highest heterogeneity index to the untreated ipsilateral lung lobes. The procedure may be performed under deep sedation or preferably under general anesthesia. After positioning of the BTVA catheter and occlusion of the target segment by the occlusion balloon, heated water vapor is delivered in a predetermined specified time according to the vapor dose. After the procedure, patients should be strictly monitored to proactively detect symptoms of localized inflammatory reaction that may temporarily worsen the clinical status of the patient and to detect complications. As the data are still very limited, BTVA should be performed within clinical trials or comprehensive registries where the product is commercially available. © 2018 S. Karger AG, Basel.

SU-E-J-35: Using CBCT as the Alternative Method of Assessing ITV Volume

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

Liao, Y; Turian, J; Templeton, A

2015-06-15

Purpose To study the accuracy of Internal Target Volumes (ITVs) created on cone beam CT (CBCT) by comparing the visible target volume on CBCT to volumes (GTV, ITV, and PTV) outlined on free breathing (FB) CT and 4DCT. Methods A Quasar Cylindrical Motion Phantom with a 3cm diameter ball (14.14 cc) embedded within a cork insert was set up to simulate respiratory motion with a period of 4 seconds and amplitude of 2cm superioinferiorly and 1cm anterioposteriorly. FBCT and 4DCT images were acquired. A PTV-4D was created on the 4DCT by applying a uniform margin of 5mm to the ITV-CT.more » PTV-FB was created by applying a margin of the motion range plus 5mm, i.e. total of 1.5cm laterally and 2.5cm superioinferiorly to the GTV outlined on the FBCT. A dynamic conformal arc was planned to treat the PTV-FB with 1mm margin. A CBCT was acquired before the treatment, on which the target was delineated. During the treatment, the position of the target was monitored using the EPID in cine mode. Results ITV-CBCT and ITV-CT were measured to be 56.6 and 62.7cc, respectively, with a Dice Coefficient (DC) of 0.94 and disagreement in center of mass (COM) of 0.59 mm. On the other hand, GTV-FB was 11.47cc, 19% less than the known volume of the ball. PTV-FB and PTV-4D were 149 and 116 cc, with a DC of 0.71. Part of the ITV-CT was not enclosed by the PTV-FB despite the large margin. The cine EPID images have confirmed geometrical misses of the target. Similar under-coverage was observed in one clinical case and captured by the CBCT, where the implanted fiducials moved outside PTV-FB. Conclusion ITV-CBCT is in good agreement with ITV-CT. When 4DCT was not available, CBCT can be an effective alternative in determining and verifying the PTV margin.« less

The performance of the progressive resolution optimizer (PRO) for RapidArc planning in targets with low-density media.

PubMed

Kan, Monica W K; Leung, Lucullus H T; Yu, Peter K N

2013-11-04

A new version of progressive resolution optimizer (PRO) with an option of air cavity correction has been implemented for RapidArc volumetric-modulated arc therapy (RA). The purpose of this study was to compare the performance of this new PRO with the use of air cavity correction option (PRO10_air) against the one without the use of the air cavity correction option (PRO10_no-air) for RapidArc planning in targets with low-density media of different sizes and complexities. The performance of PRO10_no-air and PRO10_air was initially compared using single-arc plans created for four different simple heterogeneous phantoms with virtual targets and organs at risk. Multiple-arc planning of 12 real patients having nasopharyngeal carcinomas (NPC) and ten patients having non-small cell lung cancer (NSCLC) were then performed using the above two options for further comparison. Dose calculations were performed using both the Acuros XB (AXB) algorithm with the dose to medium option and the analytical anisotropic algorithm (AAA). The effect of using intermediate dose option after the first optimization cycle in PRO10_air and PRO10_no-air was also investigated and compared. Plans were evaluated and compared using target dose coverage, critical organ sparing, conformity index, and dose homogeneity index. For NSCLC cases or cases for which large volumes of low-density media were present in or adjacent to the target volume, the use of the air cavity correction option in PRO10 was shown to be beneficial. For NPC cases or cases for which small volumes of both low- and high-density media existed in the target volume, the use of air cavity correction in PRO10 did not improve the plan quality. Based on the AXB dose calculation results, the use of PRO10_air could produce up to 18% less coverage to the bony structures of the planning target volumes for NPC cases. When the intermediate dose option in PRO10 was used, there was negligible difference observed in plan quality between

The performance of the progressive resolution optimizer (PRO) for RapidArc planning in targets with low‐density media

PubMed Central

Leung, Lucullus H.T.; Yu, Peter K.N.

2013-01-01

A new version of progressive resolution optimizer (PRO) with an option of air cavity correction has been implemented for RapidArc volumetric‐modulated arc therapy (RA). The purpose of this study was to compare the performance of this new PRO with the use of air cavity correction option (PRO10_air) against the one without the use of the air cavity correction option (PRO10_no‐air) for RapidArc planning in targets with low‐density media of different sizes and complexities. The performance of PRO10_no‐air and PRO10_air was initially compared using single‐arc plans created for four different simple heterogeneous phantoms with virtual targets and organs at risk. Multiple‐arc planning of 12 real patients having nasopharyngeal carcinomas (NPC) and ten patients having non‐small cell lung cancer (NSCLC) were then performed using the above two options for further comparison. Dose calculations were performed using both the Acuros XB (AXB) algorithm with the dose to medium option and the analytical anisotropic algorithm (AAA). The effect of using intermediate dose option after the first optimization cycle in PRO10_air and PRO10_no‐air was also investigated and compared. Plans were evaluated and compared using target dose coverage, critical organ sparing, conformity index, and dose homogeneity index. For NSCLC cases or cases for which large volumes of low‐density media were present in or adjacent to the target volume, the use of the air cavity correction option in PROIO was shown to be beneficial. For NPC cases or cases for which small volumes of both low‐ and high‐density media existed in the target volume, the use of air cavity correction in PRO10 did not improve the plan quality. Based on the AXB dose calculation results, the use of PRO10_air could produce up to 18% less coverage to the bony structures of the planning target volumes for NPC cases. When the intermediate dose option in PRO10 was used, there was negligible difference observed in plan

Short Communication: Conformal Therapy for Peri-Ventricular Brain Tumors: Is Target Volume Deformation an Issue?

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

Bauman, Glenn; Woodford, Curtis; Yartsev, Slav

2008-04-01

Physiologic variations in ventricular volumes could have important implications for treating patients with peri-ventricular brain tumors, yet no data exist in the literature addressing this issue. Daily megavoltage computed tomography (CT) scans in a patient with neurocytoma receiving fractionated radiation revealed minimal changes, suggesting that margins accounting for ventricular deformation are not necessary.

Method to Reduce Target Motion Through Needle-Tissue Interactions.

PubMed

Oldfield, Matthew J; Leibinger, Alexander; Seah, Tian En Timothy; Rodriguez Y Baena, Ferdinando

2015-11-01

During minimally invasive surgical procedures, it is often important to deliver needles to particular tissue volumes. Needles, when interacting with a substrate, cause deformation and target motion. To reduce reliance on compensatory intra-operative imaging, a needle design and novel delivery mechanism is proposed. Three-dimensional finite element simulations of a multi-segment needle inserted into a pre-existing crack are presented. The motion profiles of the needle segments are varied to identify methods that reduce target motion. Experiments are then performed by inserting a needle into a gelatine tissue phantom and measuring the internal target motion using digital image correlation. Simulations indicate that target motion is reduced when needle segments are stroked cyclically and utilise a small amount of retraction instead of being held stationary. Results are confirmed experimentally by statistically significant target motion reductions of more than 8% during cyclic strokes and 29% when also incorporating retraction, with the same net insertion speed. By using a multi-segment needle and taking advantage of frictional interactions on the needle surface, it is demonstrated that target motion ahead of an advancing needle can be substantially reduced.

Wyoming Low-Volume Roads Traffic Volume Estimation

DOT National Transportation Integrated Search

2015-10-01

Low-volume roads are excluded from regular traffic counts except on a need to know basis. But needs for traffic volume data on low-volume roads in road infrastructure management, safety, and air quality analysis have necessitated regular traffic volu...

Upper Extremity Muscle Volumes and Functional Strength After Resistance Training in Older Adults

PubMed Central

Daly, Melissa; Vidt, Meghan E.; Eggebeen, Joel D.; Simpson, W. Greg; Miller, Michael E.; Marsh, Anthony P.; Saul, Katherine R.

2014-01-01

Aging leads to a decline in strength and an associated loss of independence. The authors examined changes in muscle volume, maximum isometric joint moment, functional strength, and 1-repetition maximum (1RM) after resistance training (RT) in the upper extremity of older adults. They evaluated isometric joint moment and muscle volume as predictors of functional strength. Sixteen healthy older adults (average age 75 ± 4.3 yr) were randomized to a 6-wk upper extremity RT program or control group. The RT group increased 1RM significantly (p < .01 for all exercises). Compared with controls, randomization to RT led to greater functional pulling strength (p = .003), isometric shoulder-adduction moment (p = .041), elbow-flexor volume (p = .017), and shoulder-adductor volume (p = .009). Shoulder-muscle volumes and isometric moments were good predictors of functional strength. The authors conclude that shoulder strength is an important factor for performing functional reaching and pulling tasks and a key target for upper extremity RT interventions. PMID:22952203

Computer-aided target tracking in motion analysis studies

NASA Astrophysics Data System (ADS)

Burdick, Dominic C.; Marcuse, M. L.; Mislan, J. D.

1990-08-01

Motion analysis studies require the precise tracking of reference objects in sequential scenes. In a typical situation, events of interest are captured at high frame rates using special cameras, and selected objects or targets are tracked on a frame by frame basis to provide necessary data for motion reconstruction. Tracking is usually done using manual methods which are slow and prone to error. A computer based image analysis system has been developed that performs tracking automatically. The objective of this work was to eliminate the bottleneck due to manual methods in high volume tracking applications such as the analysis of crash test films for the automotive industry. The system has proven to be successful in tracking standard fiducial targets and other objects in crash test scenes. Over 95 percent of target positions which could be located using manual methods can be tracked by the system, with a significant improvement in throughput over manual methods. Future work will focus on the tracking of clusters of targets and on tracking deformable objects such as airbags.

Infusion volume control and calculation using metronome and drop counter based intravenous infusion therapy helper.

PubMed

Park, Kyungnam; Lee, Jangyoung; Kim, Soo-Young; Kim, Jinwoo; Kim, Insoo; Choi, Seung Pill; Jeong, Sikyung; Hong, Sungyoup

2013-06-01

This study assessed the method of fluid infusion control using an IntraVenous Infusion Controller (IVIC). Four methods of infusion control (dial flow controller, IV set without correction, IV set with correction and IVIC correction) were used to measure the volume of each technique at two infusion rates. The infused fluid volume with a dial flow controller was significantly larger than other methods. The infused fluid volume was significantly smaller with an IV set without correction over time. Regarding the concordance correlation coefficient (CCC) of infused fluid volume in relation to a target volume, IVIC correction was shown to have the highest level of agreement. The flow rate measured in check mode showed a good agreement with the volume of collected fluid after passing through the IV system. Thus, an IVIC could assist in providing an accurate infusion control. © 2013 Wiley Publishing Asia Pty Ltd.

Measuring pedestrian volumes and conflicts. Volume 1, Pedestrian volume sampling

DOT National Transportation Integrated Search

1987-12-01

This final report presents the findings, conclusions, and recommendations of the study conducted to develop a model to predict pedestrian volumes using small sampling schemes. This research produced four pedestrian volume prediction models (i.e., 1-,...

Time-Adjusted Internal Target Volume: A Novel Approach Focusing on Heterogeneity of Tumor Motion Based on 4-Dimensional Computed Tomography Imaging for Radiation Therapy Planning of Lung Cancer

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

Nishibuchi, Ikuno; Department of Radiation Oncology, Hiroshima Prefectural Hospital, Hiroshima; Kimura, Tomoki, E-mail: tkkimura@hiroshima-u.ac.jp

2014-08-01

Purpose: To consider nonuniform tumor motion within the internal target volume (ITV) by defining time-adjusted ITV (TTV), a volume designed to include heterogeneity of tumor existence on the basis of 4-dimensional computed tomography (4D-CT). Methods and Materials: We evaluated 30 lung cancer patients. Breath-hold CT (BH-CT) and free-breathing 4D-CT scans were acquired for each patient. The tumors were manually delineated using a lung CT window setting (window, 1600 HU; level, −300 HU). Tumor in BH-CT images was defined as gross tumor volume (GTV), and the sum of tumors in 4D-CT images was defined as ITV-4D. The TTV images were generatedmore » from the 4D-CT datasets, and the tumor existence probability within ITV-4D was calculated. We calculated the TTV{sub 80} value, which is the percentage of the volume with a tumor existence probability that exceeded 80% on ITV-4D. Several factors that affected the TTV{sub 80} value, such as the ITV-4D/GTV ratio or tumor centroid deviation, were evaluated. Results: Time-adjusted ITV images were acquired for all patients, and tumor respiratory motion heterogeneity was visualized. The median (range) ITV-4D/GTV ratio and median tumor centroid deviation were 1.6 (1.0-4.1) and 6.3 mm (0.1-30.3 mm), respectively. The median TTV{sub 80} value was 43.3% (2.9-98.7%). Strong correlations were observed between the TTV{sub 80} value and the ITV-4D/GTV ratio (R=−0.71) and tumor centroid deviation (R=−0.72). The TTV images revealed the tumor motion pattern features within ITV. Conclusions: The TTV images reflected nonuniform tumor motion, and they revealed the tumor motion pattern features, suggesting that the TTV concept may facilitate various aspects of radiation therapy planning of lung cancer while incorporating respiratory motion in the future.« less

Influence of gestational age on dead space and alveolar ventilation in preterm infants ventilated with volume guarantee.

PubMed

Neumann, Roland P; Pillow, Jane J; Thamrin, Cindy; Larcombe, Alexander N; Hall, Graham L; Schulzke, Sven M

2015-01-01

Ventilated preterm infant lungs are vulnerable to overdistension and underinflation. The optimal ventilator-delivered tidal volume (VT) in these infants is unknown and may depend on the extent of alveolarisation at birth. We aimed to calculate respiratory dead space (VD) from the molar mass (MM) signal of an ultrasonic flowmeter (VD,MM) in very preterm infants on volume-targeted ventilation (VT target, 4-5 ml/kg) and to study the association between gestational age (GA) and VD,MM-to-VT ratio (VD,MM/VT), alveolar tidal volume (VA) and alveolar minute volume (AMV). This was a single-centre, prospective, observational, cohort study in a neonatal intensive care unit. Tidal breathing analysis was performed in ventilated very preterm infants (GA range 23-32 weeks) on day 1 of life. Valid measurements were obtained in 43/51 (87%) infants. Tidal breathing variables were analysed using multivariable linear regression. VD,MM/VT was negatively associated with GA after adjusting for birth weight Z score (p < 0.001, R(2) = 0.26). This association was primarily influenced by the appliance dead space. Despite similar VT/kg and VA/kg across all studied infants, respiratory rate and AMV/kg increased with GA. VD,app rather than anatomical VD is the major factor influencing increased VD,MM/VT at a younger GA. A volume guarantee setting of 4-5 ml/kg in the Dräger Babylog® 8000 plus ventilator may be inappropriate as a universal target across the GA range of 23-32 weeks. Differences between measured and set VT and the dependence of this difference on GA require further investigation. © 2014 S. Karger AG, Basel.

Methods and computer executable instructions for rapidly calculating simulated particle transport through geometrically modeled treatment volumes having uniform volume elements for use in radiotherapy

DOEpatents

Frandsen, Michael W.; Wessol, Daniel E.; Wheeler, Floyd J.

2001-01-16

Methods and computer executable instructions are disclosed for ultimately developing a dosimetry plan for a treatment volume targeted for irradiation during cancer therapy. The dosimetry plan is available in "real-time" which especially enhances clinical use for in vivo applications. The real-time is achieved because of the novel geometric model constructed for the planned treatment volume which, in turn, allows for rapid calculations to be performed for simulated movements of particles along particle tracks there through. The particles are exemplary representations of neutrons emanating from a neutron source during BNCT. In a preferred embodiment, a medical image having a plurality of pixels of information representative of a treatment volume is obtained. The pixels are: (i) converted into a plurality of substantially uniform volume elements having substantially the same shape and volume of the pixels; and (ii) arranged into a geometric model of the treatment volume. An anatomical material associated with each uniform volume element is defined and stored. Thereafter, a movement of a particle along a particle track is defined through the geometric model along a primary direction of movement that begins in a starting element of the uniform volume elements and traverses to a next element of the uniform volume elements. The particle movement along the particle track is effectuated in integer based increments along the primary direction of movement until a position of intersection occurs that represents a condition where the anatomical material of the next element is substantially different from the anatomical material of the starting element. This position of intersection is then useful for indicating whether a neutron has been captured, scattered or exited from the geometric model. From this intersection, a distribution of radiation doses can be computed for use in the cancer therapy. The foregoing represents an advance in computational times by multiple factors of

Autoradiography imaging in targeted alpha therapy with Timepix detector.

PubMed

A L Darwish, Ruqaya; Staudacher, Alexander Hugo; Bezak, Eva; Brown, Michael Paul

2015-01-01

There is a lack of data related to activity uptake and particle track distribution in targeted alpha therapy. These data are required to estimate the absorbed dose on a cellular level as alpha particles have a limited range and traverse only a few cells. Tracking of individual alpha particles is possible using the Timepix semiconductor radiation detector. We investigated the feasibility of imaging alpha particle emissions in tumour sections from mice treated with Thorium-227 (using APOMAB), with and without prior chemotherapy and Timepix detector. Additionally, the sensitivity of the Timepix detector to monitor variations in tumour uptake based on the necrotic tissue volume was also studied. Compartmental analysis model was used, based on the obtained imaging data, to assess the Th-227 uptake. Results show that alpha particle, photon, electron, and muon tracks were detected and resolved by Timepix detector. The current study demonstrated that individual alpha particle emissions, resulting from targeted alpha therapy, can be visualised and quantified using Timepix detector. Furthermore, the variations in the uptake based on the tumour necrotic volume have been observed with four times higher uptake for tumours pretreated with chemotherapy than for those without chemotherapy.

Autoradiography Imaging in Targeted Alpha Therapy with Timepix Detector

PubMed Central

AL Darwish, Ruqaya; Staudacher, Alexander Hugo; Bezak, Eva; Brown, Michael Paul

2015-01-01

There is a lack of data related to activity uptake and particle track distribution in targeted alpha therapy. These data are required to estimate the absorbed dose on a cellular level as alpha particles have a limited range and traverse only a few cells. Tracking of individual alpha particles is possible using the Timepix semiconductor radiation detector. We investigated the feasibility of imaging alpha particle emissions in tumour sections from mice treated with Thorium-227 (using APOMAB), with and without prior chemotherapy and Timepix detector. Additionally, the sensitivity of the Timepix detector to monitor variations in tumour uptake based on the necrotic tissue volume was also studied. Compartmental analysis model was used, based on the obtained imaging data, to assess the Th-227 uptake. Results show that alpha particle, photon, electron, and muon tracks were detected and resolved by Timepix detector. The current study demonstrated that individual alpha particle emissions, resulting from targeted alpha therapy, can be visualised and quantified using Timepix detector. Furthermore, the variations in the uptake based on the tumour necrotic volume have been observed with four times higher uptake for tumours pretreated with chemotherapy than for those without chemotherapy. PMID:25688285

Ultrafast laser ablation for targeted atherosclerotic plaque removal

NASA Astrophysics Data System (ADS)

Lanvin, Thomas; Conkey, Donald B.; Descloux, Laurent; Frobert, Aurelien; Valentin, Jeremy; Goy, Jean-Jacques; Cook, Stéphane; Giraud, Marie-Noelle; Psaltis, Demetri

2015-07-01

Coronary artery disease, the main cause of heart disease, develops as immune cells and lipids accumulate into plaques within the coronary arterial wall. As a plaque grows, the tissue layer (fibrous cap) separating it from the blood flow becomes thinner and increasingly susceptible to rupturing and causing a potentially lethal thrombosis. The stabilization and/or treatment of atherosclerotic plaque is required to prevent rupturing and remains an unsolved medical problem. Here we show for the first time targeted, subsurface ablation of atherosclerotic plaque using ultrafast laser pulses. Excised atherosclerotic mouse aortas were ablated with ultrafast near-infrared (NIR) laser pulses. The physical damage was characterized with histological sections of the ablated atherosclerotic arteries from six different mice. The ultrafast ablation system was integrated with optical coherence tomography (OCT) imaging for plaque-specific targeting and monitoring of the resulting ablation volume. We find that ultrafast ablation of plaque just below the surface is possible without causing damage to the fibrous cap, which indicates the potential use of ultrafast ablation for subsurface atherosclerotic plaque removal. We further demonstrate ex vivo subsurface ablation of a plaque volume through a catheter device with the high-energy ultrafast pulse delivered via hollow-core photonic crystal fiber.

When high-volume PCI operators in high-volume hospitals move to lower volume hospitals-Do they still maintain high volume and quality of outcomes?

PubMed

Lu, Tsung-Hsueh; Li, Sheng-Tun; Liang, Fu-Wen; Lee, Jo-Chi; Yin, Wei-Hsian

2017-10-31

The aim of this quasi-experimental study was to examine whether high-volume percutaneous coronary intervention (PCI) operators still maintain high volume and quality of outcomes when they moved to lower volume hospitals. Systematic reviews have indicated that high-volume PCI operators and hospitals have higher quality outcomes. However, little is known on whether high PCI volume and high quality outcomes are mainly due to operator characteristics (i.e., skill and experience) and is portable across organizations or whether it is due to hospital characteristics (i.e., equipment, team, and management system) and is less portable. We used Taiwan National Health Insurance claims data 2000-2012 to identify 98 high-volume PCI operators, 10 of whom moved from one hospital to another during the study period. We compared the PCI volume, risk-adjusted mortality ratio, and major adverse cardiovascular event (MACE) ratio before and after moving. Of the 10 high-volume operators who moved, 6 moved from high- to moderate- or low-volume hospitals, with median annual PCI volumes (interquartile range) of 130 (117-165) in prior hospitals and 54 (46-84) in subsequent hospitals (the hospital the operator moved to), and the remaining 4 moved from high to high-volume hospitals, with median annual PCI volumes (interquartile range) of 151 (133-162) in prior hospitals and 193 (178-239) in subsequent hospitals. No significant differences were observed in the risk-adjusted mortality ratios and MACE ratios between high-volume operators and matched controls before and after moving. High-volume operators cannot maintain high volume when they moved from high to moderate or low-volume hospitals; however, the quality of care is maintained. High PCI volume and high-quality outcomes are less portable and more hospital bound. © 2017 Wiley Periodicals, Inc.

Dosimetric feasibility of an “off-target isocenter” technique for cranial intensity-modulated radiosurgery

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

Calvo-Ortega, Juan Francisco, E-mail: jfcdrr@yahoo.es; Moragues, Sandra; Pozo, Miquel

2015-01-01

To evaluate the dosimetric effect of placing the isocenter away from the planning target volume (PTV) on intensity-modulated radiosurgery (IMRS) plans to treat brain lesions. A total of 15 patients who received cranial IMRS at our institution were randomly selected. Each patient was treated with an IMRS plan designed with the isocenter located at the target center (plan A). A second off-target isocenter plan (plan B) was generated for each case. In all the plans,100% of the prescription dose covered 99% of the target volume. The plans A and B were compared for the target dosage (conformity index [CI] andmore » homogeneity index) and organs-at-risk (OAR) dose sparing. Peripheral dose falloff was compared by using the metrics volume of normal brain receiving more than 12-Gy dose (V12) and CI at the level of the 50% of the prescription dose (CI 50%). The values found for each metric (plan B vs plan A) were (mean ± standard deviation [SD]) as follows—CI: 1.28 ± 0.15 vs 1.28 ± 0.15, p = 0.978; homogeneity index (HI): 1.29 ± 0.14 vs 1.34 ± 0.17, p = 0.079; maximum dose to the brainstem: 2.95 ± 2.11 vs 2.89 ± 1.88 Gy, p = 0.813; maximum dose to the optical pathway: 2.65 ± 4.18 vs 2.44 ± 4.03 Gy, p = 0.195; and maximum dose to the eye lens: 0.33 ± 0.73 vs 0.33 ± 0.53 Gy, p = 0.970. The values of the peripheral dose falloff were (plan B vs plan A) as follows—V12: 5.98 ± 4.95 vs 6.06 ± 4.92 cm{sup 3}, p = 0.622, and CI 50%: 6.08 ± 2.77 vs 6.28 ± 3.01, p = 0.119. The off-target isocenter solution resulted in dosimetrically comparable plans as the center-target isocenter technique, by avoiding the risk of gantry-couch collision during the cone beam computed tomography (CBCT) acquisition.« less

Dosimetric comparison between conventional and conformal radiotherapy for carcinoma cervix: Are we treating the right volumes?

PubMed Central

Goswami, Jyotirup; Patra, Niladri B.; Sarkar, Biplab; Basu, Ayan; Pal, Santanu

2013-01-01

Background and Purpose: Conventional portals, based on bony anatomy, for external beam radiotherapy for cervical cancer have been repeatedly demonstrated as inadequate. Conversely, with image-based conformal radiotherapy, better target coverage may be offset by the greater toxicities and poorer compliance associated with treating larger volumes. This study was meant to dosimetrically compare conformal and conventional radiotherapy. Materials and Methods: Five patients of carcinoma cervix underwent planning CT scan with IV contrast and targets, and organs at risk (OAR) were contoured. Two sets of plans-conventional and conformal were generated for each patient. Field sizes were recorded, and dose volume histograms of both sets of plans were generated and compared on the basis of target coverage and OAR sparing. Results: Target coverage was significantly improved with conformal plans though field sizes required were significantly larger. On the other hand, dose homogeneity was not significantly improved. Doses to the OARs (rectum, urinary bladder, and small bowel) were not significantly different across the 2 arms. Conclusion: Three-dimensional conformal radiotherapy gives significantly better target coverage, which may translate into better local control and survival. On the other hand, it also requires significantly larger field sizes though doses to the OARs are not significantly increased. PMID:24455584

Gamma Knife irradiation method based on dosimetric controls to target small areas in rat brains

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

Constanzo, Julie; Paquette, Benoit; Charest, Gabriel

2015-05-15

Purpose: Targeted and whole-brain irradiation in humans can result in significant side effects causing decreased patient quality of life. To adequately investigate structural and functional alterations after stereotactic radiosurgery, preclinical studies are needed. The purpose of this work is to establish a robust standardized method of targeted irradiation on small regions of the rat brain. Methods: Euthanized male Fischer rats were imaged in a stereotactic bed, by computed tomography (CT), to estimate positioning variations relative to the bregma skull reference point. Using a rat brain atlas and the stereotactic bregma coordinates obtained from CT images, different regions of the brainmore » were delimited and a treatment plan was generated. A single isocenter treatment plan delivering ≥100 Gy in 100% of the target volume was produced by Leksell GammaPlan using the 4 mm diameter collimator of sectors 4, 5, 7, and 8 of the Gamma Knife unit. Impact of positioning deviations of the rat brain on dose deposition was simulated by GammaPlan and validated with dosimetric measurements. Results: The authors’ results showed that 90% of the target volume received 100 ± 8 Gy and the maximum of deposited dose was 125 ± 0.7 Gy, which corresponds to an excellent relative standard deviation of 0.6%. This dose deposition calculated with GammaPlan was validated with dosimetric films resulting in a dose-profile agreement within 5%, both in X- and Z-axes. Conclusions: The authors’ results demonstrate the feasibility of standardizing the irradiation procedure of a small volume in the rat brain using a Gamma Knife.« less

The New York Head—A precise standardized volume conductor model for EEG source localization and tES targeting

PubMed Central

Huang, Yu; Parra, Lucas C.; Haufe, Stefan

2018-01-01

In source localization of electroencephalograpic (EEG) signals, as well as in targeted transcranial electric current stimulation (tES), a volume conductor model is required to describe the flow of electric currents in the head. Boundary element models (BEM) can be readily computed to represent major tissue compartments, but cannot encode detailed anatomical information within compartments. Finite element models (FEM) can capture more tissue types and intricate anatomical structures, but with the higher precision also comes the need for semiautomated segmentation, and a higher computational cost. In either case, adjusting to the individual human anatomy requires costly magnetic resonance imaging (MRI), and thus head modeling is often based on the anatomy of an ‘arbitrary’ individual (e.g. Colin27). Additionally, existing reference models for the human head often do not include the cerebrospinal fluid (CSF), and their field of view excludes portions of the head and neck—two factors that demonstrably affect current-flow patterns. Here we present a highly detailed FEM, which we call ICBM-NY, or “New York Head”. It is based on the ICBM152 anatomical template (a non-linear average of the MRI of 152 adult human brains) defined in MNI coordinates, for which we extended the field of view to the neck and performed a detailed segmentation of six tissue types (scalp, skull, CSF, gray matter, white matter, air cavities) at 0.5 mm 3 resolution. The model was solved for 231 electrode locations. To evaluate its performance, additional FEMs and BEMs were constructed for four individual subjects. Each of the four individual FEMs (regarded as the ‘ground truth’) is compared to its BEM counterpart, the ICBM-NY, a BEM of the ICBM anatomy, an ‘individualized’ BEM of the ICBM anatomy warped to the individual head surface, and FEMs of the other individuals. Performance is measured in terms of EEG source localization and tES targeting errors. Results show that the ICBM

The New York Head-A precise standardized volume conductor model for EEG source localization and tES targeting.

PubMed

Huang, Yu; Parra, Lucas C; Haufe, Stefan

2016-10-15

In source localization of electroencephalograpic (EEG) signals, as well as in targeted transcranial electric current stimulation (tES), a volume conductor model is required to describe the flow of electric currents in the head. Boundary element models (BEM) can be readily computed to represent major tissue compartments, but cannot encode detailed anatomical information within compartments. Finite element models (FEM) can capture more tissue types and intricate anatomical structures, but with the higher precision also comes the need for semi-automated segmentation, and a higher computational cost. In either case, adjusting to the individual human anatomy requires costly magnetic resonance imaging (MRI), and thus head modeling is often based on the anatomy of an 'arbitrary' individual (e.g. Colin27). Additionally, existing reference models for the human head often do not include the cerebro-spinal fluid (CSF), and their field of view excludes portions of the head and neck-two factors that demonstrably affect current-flow patterns. Here we present a highly detailed FEM, which we call ICBM-NY, or "New York Head". It is based on the ICBM152 anatomical template (a non-linear average of the MRI of 152 adult human brains) defined in MNI coordinates, for which we extended the field of view to the neck and performed a detailed segmentation of six tissue types (scalp, skull, CSF, gray matter, white matter, air cavities) at 0.5mm(3) resolution. The model was solved for 231 electrode locations. To evaluate its performance, additional FEMs and BEMs were constructed for four individual subjects. Each of the four individual FEMs (regarded as the 'ground truth') is compared to its BEM counterpart, the ICBM-NY, a BEM of the ICBM anatomy, an 'individualized' BEM of the ICBM anatomy warped to the individual head surface, and FEMs of the other individuals. Performance is measured in terms of EEG source localization and tES targeting errors. Results show that the ICBM-NY outperforms

Laser-induced extreme magnetic field in nanorod targets

NASA Astrophysics Data System (ADS)

Lécz, Zsolt; Andreev, Alexander

2018-03-01

The application of nano-structured target surfaces in laser-solid interaction has attracted significant attention in the last few years. Their ability to absorb significantly more laser energy promises a possible route for advancing the currently established laser ion acceleration concepts. However, it is crucial to have a better understanding of field evolution and electron dynamics during laser-matter interactions before the employment of such exotic targets. This paper focuses on the magnetic field generation in nano-forest targets consisting of parallel nanorods grown on plane surfaces. A general scaling law for the self-generated quasi-static magnetic field amplitude is given and it is shown that amplitudes up to 1 MT field are achievable with current technology. Analytical results are supported by three-dimensional particle-in-cell simulations. Non-parallel arrangements of nanorods has also been considered which result in the generation of donut-shaped azimuthal magnetic fields in a larger volume.

Relationships between residue Voronoi volume and sequence conservation in proteins.

PubMed

Liu, Jen-Wei; Cheng, Chih-Wen; Lin, Yu-Feng; Chen, Shao-Yu; Hwang, Jenn-Kang; Yen, Shih-Chung

2018-02-01

Functional and biophysical constraints can cause different levels of sequence conservation in proteins. Previously, structural properties, e.g., relative solvent accessibility (RSA) and packing density of the weighted contact number (WCN), have been found to be related to protein sequence conservation (CS). The Voronoi volume has recently been recognized as a new structural property of the local protein structural environment reflecting CS. However, for surface residues, it is sensitive to water molecules surrounding the protein structure. Herein, we present a simple structural determinant termed the relative space of Voronoi volume (RSV); it uses the Voronoi volume and the van der Waals volume of particular residues to quantify the local structural environment. RSV (range, 0-1) is defined as (Voronoi volume-van der Waals volume)/Voronoi volume of the target residue. The concept of RSV describes the extent of available space for every protein residue. RSV and Voronoi profiles with and without water molecules (RSVw, RSV, VOw, and VO) were compared for 554 non-homologous proteins. RSV (without water) showed better Pearson's correlations with CS than did RSVw, VO, or VOw values. The mean correlation coefficient between RSV and CS was 0.51, which is comparable to the correlation between RSA and CS (0.49) and that between WCN and CS (0.56). RSV is a robust structural descriptor with and without water molecules and can quantitatively reflect evolutionary information in a single protein structure. Therefore, it may represent a practical structural determinant to study protein sequence, structure, and function relationships. Copyright © 2017 Elsevier B.V. All rights reserved.

TU-AB-BRB-01: Coverage Evaluation and Probabilistic Treatment Planning as a Margin Alternative

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

Siebers, J.

The accepted clinical method to accommodate targeting uncertainties inherent in fractionated external beam radiation therapy is to utilize GTV-to-CTV and CTV-to-PTV margins during the planning process to design a PTV-conformal static dose distribution on the planning image set. Ideally, margins are selected to ensure a high (e.g. >95%) target coverage probability (CP) in spite of inherent inter- and intra-fractional positional variations, tissue motions, and initial contouring uncertainties. Robust optimization techniques, also known as probabilistic treatment planning techniques, explicitly incorporate the dosimetric consequences of targeting uncertainties by including CP evaluation into the planning optimization process along with coverage-based planning objectives. Themore » treatment planner no longer needs to use PTV and/or PRV margins; instead robust optimization utilizes probability distributions of the underlying uncertainties in conjunction with CP-evaluation for the underlying CTVs and OARs to design an optimal treated volume. This symposium will describe CP-evaluation methods as well as various robust planning techniques including use of probability-weighted dose distributions, probability-weighted objective functions, and coverage optimized planning. Methods to compute and display the effect of uncertainties on dose distributions will be presented. The use of robust planning to accommodate inter-fractional setup uncertainties, organ deformation, and contouring uncertainties will be examined as will its use to accommodate intra-fractional organ motion. Clinical examples will be used to inter-compare robust and margin-based planning, highlighting advantages of robust-plans in terms of target and normal tissue coverage. Robust-planning limitations as uncertainties approach zero and as the number of treatment fractions becomes small will be presented, as well as the factors limiting clinical implementation of robust planning. Learning Objectives: To

TU-AB-BRB-03: Coverage-Based Treatment Planning to Accommodate Organ Deformable Motions and Contouring Uncertainties for Prostate Treatment

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

Xu, H.

The accepted clinical method to accommodate targeting uncertainties inherent in fractionated external beam radiation therapy is to utilize GTV-to-CTV and CTV-to-PTV margins during the planning process to design a PTV-conformal static dose distribution on the planning image set. Ideally, margins are selected to ensure a high (e.g. >95%) target coverage probability (CP) in spite of inherent inter- and intra-fractional positional variations, tissue motions, and initial contouring uncertainties. Robust optimization techniques, also known as probabilistic treatment planning techniques, explicitly incorporate the dosimetric consequences of targeting uncertainties by including CP evaluation into the planning optimization process along with coverage-based planning objectives. Themore » treatment planner no longer needs to use PTV and/or PRV margins; instead robust optimization utilizes probability distributions of the underlying uncertainties in conjunction with CP-evaluation for the underlying CTVs and OARs to design an optimal treated volume. This symposium will describe CP-evaluation methods as well as various robust planning techniques including use of probability-weighted dose distributions, probability-weighted objective functions, and coverage optimized planning. Methods to compute and display the effect of uncertainties on dose distributions will be presented. The use of robust planning to accommodate inter-fractional setup uncertainties, organ deformation, and contouring uncertainties will be examined as will its use to accommodate intra-fractional organ motion. Clinical examples will be used to inter-compare robust and margin-based planning, highlighting advantages of robust-plans in terms of target and normal tissue coverage. Robust-planning limitations as uncertainties approach zero and as the number of treatment fractions becomes small will be presented, as well as the factors limiting clinical implementation of robust planning. Learning Objectives: To

TU-AB-BRB-02: Stochastic Programming Methods for Handling Uncertainty and Motion in IMRT Planning

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

Unkelbach, J.

The accepted clinical method to accommodate targeting uncertainties inherent in fractionated external beam radiation therapy is to utilize GTV-to-CTV and CTV-to-PTV margins during the planning process to design a PTV-conformal static dose distribution on the planning image set. Ideally, margins are selected to ensure a high (e.g. >95%) target coverage probability (CP) in spite of inherent inter- and intra-fractional positional variations, tissue motions, and initial contouring uncertainties. Robust optimization techniques, also known as probabilistic treatment planning techniques, explicitly incorporate the dosimetric consequences of targeting uncertainties by including CP evaluation into the planning optimization process along with coverage-based planning objectives. Themore » treatment planner no longer needs to use PTV and/or PRV margins; instead robust optimization utilizes probability distributions of the underlying uncertainties in conjunction with CP-evaluation for the underlying CTVs and OARs to design an optimal treated volume. This symposium will describe CP-evaluation methods as well as various robust planning techniques including use of probability-weighted dose distributions, probability-weighted objective functions, and coverage optimized planning. Methods to compute and display the effect of uncertainties on dose distributions will be presented. The use of robust planning to accommodate inter-fractional setup uncertainties, organ deformation, and contouring uncertainties will be examined as will its use to accommodate intra-fractional organ motion. Clinical examples will be used to inter-compare robust and margin-based planning, highlighting advantages of robust-plans in terms of target and normal tissue coverage. Robust-planning limitations as uncertainties approach zero and as the number of treatment fractions becomes small will be presented, as well as the factors limiting clinical implementation of robust planning. Learning Objectives: To

An estimation of vehicle kilometer traveled and on-road emissions using the traffic volume and travel speed on road links in Incheon City.

PubMed

Jung, Sungwoon; Kim, Jounghwa; Kim, Jeongsoo; Hong, Dahee; Park, Dongjoo

2017-04-01

The objective of this study is to estimate the vehicle kilometer traveled (VKT) and on-road emissions using the traffic volume in urban. We estimated two VKT; one is based on registered vehicles and the other is based on traffic volumes. VKT for registered vehicles was 2.11 times greater than that of the applied traffic volumes because each VKT estimation method is different. Therefore, we had to define the inner VKT is moved VKT inner in urban to compare two values. Also, we focused on freight modes because these are discharged much air pollutant emissions. From analysis results, we found middle and large trucks registered in other regions traveled to target city in order to carry freight, target city has included many industrial and logistics areas. Freight is transferred through the harbors, large logistics centers, or via locations before being moved to the final destination. During this process, most freight is moved by middle and large trucks, and trailers rather than small trucks for freight import and export. Therefore, these trucks from other areas are inflow more than registered vehicles. Most emissions from diesel trucks had been overestimated in comparison to VKT from applied traffic volumes in target city. From these findings, VKT is essential based on traffic volume and travel speed on road links in order to estimate accurately the emissions of diesel trucks in target city. Our findings support the estimation of the effect of on-road emissions on urban air quality in Korea. Copyright © 2016. Published by Elsevier B.V.

Effects of voxelization on dose volume histogram accuracy

NASA Astrophysics Data System (ADS)

Sunderland, Kyle; Pinter, Csaba; Lasso, Andras; Fichtinger, Gabor

2016-03-01

PURPOSE: In radiotherapy treatment planning systems, structures of interest such as targets and organs at risk are stored as 2D contours on evenly spaced planes. In order to be used in various algorithms, contours must be converted into binary labelmap volumes using voxelization. The voxelization process results in lost information, which has little effect on the volume of large structures, but has significant impact on small structures, which contain few voxels. Volume differences for segmented structures affects metrics such as dose volume histograms (DVH), which are used for treatment planning. Our goal is to evaluate the impact of voxelization on segmented structures, as well as how factors like voxel size affects metrics, such as DVH. METHODS: We create a series of implicit functions, which represent simulated structures. These structures are sampled at varying resolutions, and compared to labelmaps with high sub-millimeter resolutions. We generate DVH and evaluate voxelization error for the same structures at different resolutions by calculating the agreement acceptance percentage between the DVH. RESULTS: We implemented tools for analysis as modules in the SlicerRT toolkit based on the 3D Slicer platform. We found that there were large DVH variation from the baseline for small structures or for structures located in regions with a high dose gradient, potentially leading to the creation of suboptimal treatment plans. CONCLUSION: This work demonstrates that labelmap and dose volume voxel size is an important factor in DVH accuracy, which must be accounted for in order to ensure the development of accurate treatment plans.

800-MeV proton irradiation of thorium and depleted uranium targets

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

Russell, G.J.; Brun, T.O.; Pitcher, E.J.

As part of the Los Alamos Fertile-to-Fissile-Conversion (FERFICON) program in the late 1980`s, thick targets of the fertile materials thorium and depleted uranium were bombarded by 800-MeV protons to produce the fissile materials {sup 233}U and {sup 239}Pu, respectively. The amount of {sup 233}U made was determined by measuring the {sup 233}Pa activity, and the yield of {sup 239}Pu was deduced by measuring the activity of {sup 239}Np. For the thorium target, 4 spallation products and 34 fission products were also measured. For the depleted uranium target, 3 spallation products and 16 fission products were also measured. The number ofmore » fissions in each target was deduced from fission product mass-yield curves. In actuality, axial distributions of the products were measured, and the distributions were then integrated over the target volume to obtain the total number of products for each reaction.« less

Targeted left ventricular lead placement to guide cardiac resynchronization therapy: the TARGET study: a randomized, controlled trial.

PubMed

Khan, Fakhar Z; Virdee, Mumohan S; Palmer, Christopher R; Pugh, Peter J; O'Halloran, Denis; Elsik, Maros; Read, Philip A; Begley, David; Fynn, Simon P; Dutka, David P

2012-04-24

This study sought to assess the impact of targeted left ventricular (LV) lead placement on outcomes of cardiac resynchronization therapy (CRT). Placement of the LV lead to the latest sites of contraction and away from the scar confers the best response to CRT. We conducted a randomized, controlled trial to compare a targeted approach to LV lead placement with usual care. A total of 220 patients scheduled for CRT underwent baseline echocardiographic speckle-tracking 2-dimensional radial strain imaging and were then randomized 1:1 into 2 groups. In group 1 (TARGET [Targeted Left Ventricular Lead Placement to Guide Cardiac Resynchronization Therapy]), the LV lead was positioned at the latest site of peak contraction with an amplitude of >10% to signify freedom from scar. In group 2 (control) patients underwent standard unguided CRT. Patients were classified by the relationship of the LV lead to the optimal site as concordant (at optimal site), adjacent (within 1 segment), or remote (≥2 segments away). The primary endpoint was a ≥15% reduction in LV end-systolic volume at 6 months. Secondary endpoints were clinical response (≥1 improvement in New York Heart Association functional class), all-cause mortality, and combined all-cause mortality and heart failure-related hospitalization. The groups were balanced at randomization. In the TARGET group, there was a greater proportion of responders at 6 months (70% vs. 55%, p = 0.031), giving an absolute difference in the primary endpoint of 15% (95% confidence interval: 2% to 28%). Compared with controls, TARGET patients had a higher clinical response (83% vs. 65%, p = 0.003) and lower rates of the combined endpoint (log-rank test, p = 0.031). Compared with standard CRT treatment, the use of speckle-tracking echocardiography to the target LV lead placement yields significantly improved response and clinical status and lower rates of combined death and heart failure-related hospitalization. (Targeted Left Ventricular Lead

Stereotactic body radiotherapy for primary lung cancer at a dose of 50 Gy total in five fractions to the periphery of the planning target volume calculated using a superposition algorithm.

PubMed

Takeda, Atsuya; Sanuki, Naoko; Kunieda, Etsuo; Ohashi, Toshio; Oku, Yohei; Takeda, Toshiaki; Shigematsu, Naoyuki; Kubo, Atsushi

2009-02-01

To retrospectively analyze the clinical outcomes of stereotactic body radiotherapy (SBRT) for patients with Stages 1A and 1B non-small-cell lung cancer. We reviewed the records of patients with non-small-cell lung cancer treated with curative intent between Dec 2001 and May 2007. All patients had histopathologically or cytologically confirmed disease, increased levels of tumor markers, and/or positive findings on fluorodeoxyglucose positron emission tomography. Staging studies identified their disease as Stage 1A or 1B. Performance status was 2 or less according to World Health Organization guidelines in all cases. The prescribed dose of 50 Gy total in five fractions, calculated by using a superposition algorithm, was defined for the periphery of the planning target volume. One hundred twenty-one patients underwent SBRT during the study period, and 63 were eligible for this analysis. Thirty-eight patients had Stage 1A (T1N0M0) and 25 had Stage 1B (T2N0M0). Forty-nine patients were not appropriate candidates for surgery because of chronic pulmonary disease. Median follow-up of these 49 patients was 31 months (range, 10-72 months). The 3-year local control, disease-free, and overall survival rates in patients with Stages 1A and 1B were 93% and 96% (p = 0.86), 76% and 77% (p = 0.83), and 90% and 63% (p = 0.09), respectively. No acute toxicity was observed. Grade 2 or higher radiation pneumonitis was experienced by 3 patients, and 1 of them had fatal bacterial pneumonia. The SBRT at 50 Gy total in five fractions to the periphery of the planning target volume calculated by using a superposition algorithm is feasible. High local control rates were achieved for both T2 and T1 tumors.

Measurement of limb volume: laser scanning versus volume displacement.

PubMed

McKinnon, John Gregory; Wong, Vanessa; Temple, Walley J; Galbraith, Callum; Ferry, Paul; Clynch, George S; Clynch, Colin

2007-10-01

Determining the prevalence and treatment success of surgical lymphedema requires accurate and reproducible measurement. A new method of measurement of limb volume is described. A series of inanimate objects of known and unknown volume was measured using digital laser scanning and water displacement. A similar comparison was made with 10 human volunteers. Digital scanning was evaluated by comparison to the established method of water displacement, then to itself to determine reproducibility of measurement. (1) Objects of known volume: Laser scanning accurately measured the calculated volume but water displacement became less accurate as the size of the object increased. (2) Objects of unknown volume: As average volume increased, there was an increasing bias of underestimation of volume by the water displacement method. The coefficient of reproducibility of water displacement was 83.44 ml. In contrast, the reproducibility of the digital scanning method was 19.0 ml. (3) Human data: The mean difference between water displacement volume and laser scanning volume was 151.7 ml (SD +/- 189.5). The coefficient of reproducibility of water displacement was 450.8 ml whereas for laser scanning it was 174 ml. Laser scanning is an innovative method of measuring tissue volume that combines precision and reproducibility and may have clinical utility for measuring lymphedema. 2007 Wiley-Liss, Inc

Inter- and intra-observer variation in soft-tissue sarcoma target definition.

PubMed

Roberge, D; Skamene, T; Turcotte, R E; Powell, T; Saran, N; Freeman, C

2011-08-01

To evaluate inter- and intra-observer variability in gross tumor volume definition for adult limb/trunk soft tissue sarcomas. Imaging studies of 15 patients previously treated with preoperative radiation were used in this study. Five physicians (radiation oncologists, orthopedic surgeons and a musculoskeletal radiologist) were asked to contour each of the 15 tumors on T1-weighted, gadolinium-enhanced magnetic resonance images. These contours were drawn twice by each physician. The volume and center of mass coordinates for each gross tumor volume were extracted and a Boolean analysis was performed to measure the degree of volume overlap. The median standard deviation in gross tumor volumes across observers was 6.1% of the average volume (range: 1.8%-24.9%). There was remarkably little variation in the 3D position of the gross tumor volume center of mass. For the 15 patients, the standard deviation of the 3D distance between centers of mass ranged from 0.06 mm to 1.7 mm (median 0.1mm). Boolean analysis demonstrated that 53% to 90% of the gross tumor volume was common to all observers (median overlap: 79%). The standard deviation in gross tumor volumes on repeat contouring was 4.8% (range: 0.1-14.4%) with a standard deviation change in the position of the center of mass of 0.4mm (range: 0mm-2.6mm) and a median overlap of 93% (range: 73%-98%). Although significant inter-observer differences were seen in gross tumor volume definition of adult soft-tissue sarcoma, the center of mass of these volumes was remarkably consistent. Variations in volume definition did not correlate with tumor size. Radiation oncologists should not hesitate to review their contours with a colleague (surgeon, radiologist or fellow radiation oncologist) to ensure that they are not outliers in sarcoma gross tumor volume definition. Protocols should take into account variations in volume definition when considering tighter clinical target volumes. Copyright © 2011 Société française de radioth

FDG-PET/CT imaging for tumor staging and definition of tumor volumes in radiation treatment planning in non-small cell lung cancer.

PubMed

Zheng, Yuanda; Sun, Xiaojiang; Wang, Jian; Zhang, Lingnan; DI, Xiaoyun; Xu, Yaping

2014-04-01

18 F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has the potential to improve the staging and radiation treatment (RT) planning of various tumor sites. However, from a clinical standpoint, questions remain with regard to what extent PET/CT changes the target volume and whether PET/CT reduces interobserver variability in target volume delineation. The present study analyzed the use of FDG-PET/CT images for staging and evaluated the impact of FDG-PET/CT on the radiotherapy volume delineation compared with CT in patients with non-small cell lung cancer (NSCLC) who were candidates for radiotherapy. Intraobserver variation in delineating tumor volumes was also observed. In total, 23 patients with stage I-III NSCLC were enrolled and treated with fractionated RT-based therapy with or without chemotherapy. FDG-PET/CT scans were acquired within two weeks prior to RT. PET and CT data sets were sent to the treatment planning system, Pinnacle, through compact discs. The CT and PET images were subsequently fused by means of a dedicated RT planning system. Gross tumor volume (GTV) was contoured by four radiation oncologists on CT (GTV-CT) and PET/CT images (GTV-PET/CT). The resulting volumes were analyzed and compared. For the first phase, two radiation oncologists outlined the contours together, achieving a final consensus. Based on PET/CT, changes in tumor-node-metastasis categories occurred in 8/23 cases (35%). Radiation targeting with fused FDG-PET and CT images resulted in alterations in radiation therapy planning in 12/20 patients (60%) in comparison with CT targeting. The most prominent changes in GTV were observed in cases with atelectasis. For the second phase, the variation in delineating tumor volumes was assessed by four observers. The mean ratio of largest to smallest CT-based GTV was 2.31 (range, 1.01-5.96). The addition of the PET results reduced the mean ratio to 1.46 (range, 1.02-2.27). PET/CT fusion images may have a

Assessment of Prospectively Assigned Likert Scores for Targeted Magnetic Resonance Imaging-Transrectal Ultrasound Fusion Biopsies in Patients with Suspected Prostate Cancer.

PubMed

Costa, Daniel N; Lotan, Yair; Rofsky, Neil M; Roehrborn, Claus; Liu, Alexander; Hornberger, Brad; Xi, Yin; Francis, Franto; Pedrosa, Ivan

2016-01-01

We assess the performance of prospectively assigned magnetic resonance imaging based Likert scale scores for the detection of clinically significant prostate cancer, and analyze the pre-biopsy imaging variables associated with increased cancer detection using targeted magnetic resonance imaging-transrectal ultrasound fusion biopsy. In this retrospective review of prospectively generated data including men with abnormal multiparametric prostate magnetic resonance imaging (at least 1 Likert score 3 or greater lesion) who underwent subsequent targeted magnetic resonance imaging-transrectal ultrasound fusion biopsy, we determined the association between different imaging variables (Likert score, lesion size, lesion location, prostate volume, radiologist experience) and targeted biopsy positivity rate. We also compared the detection of clinically significant cancer according to Likert scale scores. Tumors with high volume (50% or more of any core) Gleason score 3+4 or any tumor with greater Gleason score were considered clinically significant. Each lesion served as the elementary unit for analysis. We used logistic regression for univariate and multivariate (stepwise selection) analysis to assess for an association between targeted biopsy positivity rate and each tested variable. The relationship between Likert scale and Gleason score was evaluated using the Spearman correlation coefficient. A total of 161 men with 244 lesions met the study eligibility criteria. Targeted biopsies diagnosed cancer in 41% (66 of 161) of the men and 41% (99 of 244) of the lesions. The Likert score was the strongest predictor of targeted biopsy positivity (OR 3.7, p <0.0001). Other imaging findings associated with a higher targeted biopsy positivity rate included smaller prostate volume (OR 0.7, p <0.01), larger lesion size (OR 2.2, p <0.001) and anterior location (OR 2.0, p=0.01). On multiple logistic regression analysis Likert score, lesion size and prostate volume were significant

Microfluidic devices for the controlled manipulation of small volumes

DOEpatents

Ramsey, J Michael [Knoxville, TN; Jacobson, Stephen C [Knoxville, TN

2003-02-25

A method for conducting a broad range of biochemical analyses or manipulations on a series of nano- to subnanoliter reaction volumes and an apparatus for carrying out the same are disclosed. The method and apparatus are implemented on a fluidic microchip to provide high serial throughput. The method and device of the invention also lend themselves to multiple parallel analyses and manipulation to provide greater throughput for the generation of biochemical information. In particular, the disclosed device is a microfabricated channel device that can manipulate nanoliter or subnanoliter biochemical reaction volumes in a controlled manner to produce results at rates of 1 to 10 Hz per channel. The individual reaction volumes are manipulated in serial fashion analogous to a digital shift register. The method and apparatus according to this invention have application to such problems as screening molecular or cellular targets using single beads from split-synthesis combinatorial libraries, screening single cells for RNA or protein expression, genetic diagnostic screening at the single cell level, or performing single cell signal transduction studies.

Patterns of local-regional recurrence following parotid-sparing conformal and segmental intensity-modulated radiotherapy for head and neck cancer.

PubMed

Dawson, L A; Anzai, Y; Marsh, L; Martel, M K; Paulino, A; Ship, J A; Eisbruch, A

2000-03-15

To analyze the patterns of local-regional recurrence in patients with head and neck cancer treated with parotid-sparing conformal and segmental intensity-modulated radiotherapy (IMRT). Fifty-eight patients with head and neck cancer were treated with bilateral neck radiation (RT) using conformal or segmental IMRT techniques, while sparing a substantial portion of one parotid gland. The targets for CT-based RT planning included the gross tumor volume (GTV) (primary tumor and lymph node metastases) and the clinical target volume (CTV) (postoperative tumor bed, expansions of the GTVs and lymph node groups at risk of subclinical disease). Lymph node targets at risk of subclinical disease included the bilateral jugulodigastric and lower jugular lymph nodes, bilateral retropharyngeal lymph nodes at risk, and high jugular nodes at the base of skull in the side of the neck at highest risk (containing clinical neck metastases and/or ipsilateral to the primary tumor). The CTVs were expanded by 5 mm to yield planning target volumes (PTVs). Planning goals included coverage of all PTVs (with a minimum of 95% of the prescribed dose) and sparing of a substantial portion of the parotid gland in the side of the neck at less risk. The median RT doses to the gross tumor, the operative bed, and the subclinical disease PTVs were 70.4 Gy, 61.2 Gy, and 50.4 Gy respectively. All recurrences were defined on CT scans obtained at the time of recurrence, transferred to the pretreatment CT dataset used for RT planning, and analyzed using dose-volume histograms. The recurrences were classified as 1) "in-field," in which 95% or more of the recurrence volume (V(recur)) was within the 95% isodose; 2) "marginal," in which 20% to 95% of V(recur) was within the 95% isodose; or 3) "outside," in which less than 20% of V(recur) was within the 95% isodose. With a median follow-up of 27 months (range 6 to 60 months), 10 regional recurrences, 5 local recurrences (including one noninvasive recurrence) and 1

Liquid crystal films as on-demand, variable thickness (50–5000 nm) targets for intense lasers

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

Poole, P. L., E-mail: poole.134@osu.edu; Andereck, C. D.; Schumacher, D. W.

2014-06-15

We have developed a new type of target for intense laser-matter experiments that offers significant advantages over those currently in use. The targets consist of a liquid crystal film freely suspended within a metal frame. They can be formed rapidly on-demand with thicknesses ranging from nanometers to micrometers, where the particular value is determined by the liquid crystal temperature and initial volume as well as by the frame geometry. The liquid crystal used for this work, 8CB (4′-octyl-4-cyanobiphenyl), has a vapor pressure below 10{sup −6} Torr, so films made at atmospheric pressure maintain their initial thickness after pumping to high vacuum.more » Additionally, the volume per film is such that each target costs significantly less than one cent to produce. The mechanism of film formation and relevant physics of liquid crystals are described, as well as ion acceleration data from the first shots on liquid crystal film targets at the Ohio State University Scarlet laser facility.« less

LLE Review Quarterly Report (October-December 2001). Volume 89

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

Donaldson, William R.

2001-12-01

This volume of the LLE Review, covering October-December 2001, features “Time-Integrated Light Images of OMEGA Implosions” by P. Morley and W. Seka (p. 1). E. Kowaluk initiated this project for aesthetic rather than scientific reasons when he began taking visible light photographs of imploding OMEGA targets. These beautiful images are used to communicate LLE’s mission to the general public. A closer examination of the images revealed a one-to-one correspondence between the bright spots in the image and each of the 60 laser beams. The intensity of the bright spots has been related to refraction and absorption in the plasma surroundingmore » the imploding target. These photographs are now proving to be the basis of a new laser-plasma interaction diagnostic. Other articles in this volume are titled the following: Analytical Model of Nonlinear, Single-Mode, Classical Rayleigh-Taylor Instability at Arbitrary Atwood Numbers; A High-Pass Phase Plate Design for OMEGA and the NIF; Advanced Tritium Recovery System; Establishing Links Between Single Gold Nanoparticles Buried Inside SiO 2 Thin Film and 351-nm Pulsed-Laser-Damage Morphology; Resistive Switching Dynamics in Current-Biased Y-Ba-Cu-O Microbridges Excited by Nanosecond Electrical Pulses; and, Properties of Amorphous Carbon Films.« less

Prediction of resource volumes at untested locations using simple local prediction models

USGS Publications Warehouse

Attanasi, E.D.; Coburn, T.C.; Freeman, P.A.

2006-01-01

This paper shows how local spatial nonparametric prediction models can be applied to estimate volumes of recoverable gas resources at individual undrilled sites, at multiple sites on a regional scale, and to compute confidence bounds for regional volumes based on the distribution of those estimates. An approach that combines cross-validation, the jackknife, and bootstrap procedures is used to accomplish this task. Simulation experiments show that cross-validation can be applied beneficially to select an appropriate prediction model. The cross-validation procedure worked well for a wide range of different states of nature and levels of information. Jackknife procedures are used to compute individual prediction estimation errors at undrilled locations. The jackknife replicates also are used with a bootstrap resampling procedure to compute confidence bounds for the total volume. The method was applied to data (partitioned into a training set and target set) from the Devonian Antrim Shale continuous-type gas play in the Michigan Basin in Otsego County, Michigan. The analysis showed that the model estimate of total recoverable volumes at prediction sites is within 4 percent of the total observed volume. The model predictions also provide frequency distributions of the cell volumes at the production unit scale. Such distributions are the basis for subsequent economic analyses. ?? Springer Science+Business Media, LLC 2007.

SU-E-J-44: A Novel Approach to Quantify Patient Setup and Target Motion for Real-Time Image-Guided Radiotherapy (IGRT)

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

Li, S; Charpentier, P; Sayler, E

2015-06-15

Purpose Isocenter shifts and rotations to correct patient setup errors and organ motion cannot remedy some shape changes of large targets. We are investigating new methods in quantification of target deformation for realtime IGRT of breast and chest wall cancer. Methods Ninety-five patients of breast or chest wall cancer were accrued in an IRB-approved clinical trial of IGRT using 3D surface images acquired at daily setup and beam-on time via an in-room camera. Shifts and rotations relating to the planned reference surface were determined using iterative-closest-point alignment. Local surface displacements and target deformation are measured via a ray-surface intersection andmore » principal component analysis (PCA) of external surface, respectively. Isocenter shift, upper-abdominal displacement, and vectors of the surface projected onto the two principal components, PC1 and PC2, were evaluated for sensitivity and accuracy in detection of target deformation. Setup errors for some deformed targets were estimated by superlatively registering target volume, inner surface, or external surface in weekly CBCT or these outlines on weekly EPI. Results Setup difference according to the inner-surface, external surface, or target volume could be 1.5 cm. Video surface-guided setup agreed with EPI results to within < 0.5 cm while CBCT results were sometimes (∼20%) different from that of EPI (>0.5 cm) due to target deformation for some large breasts and some chest walls undergoing deep-breath-hold irradiation. Square root of PC1 and PC2 is very sensitive to external surface deformation and irregular breathing. Conclusion PCA of external surfaces is quick and simple way to detect target deformation in IGRT of breast and chest wall cancer. Setup corrections based on the target volume, inner surface, and external surface could be significant different. Thus, checking of target shape changes is essential for accurate image-guided patient setup and motion tracking of large

Target-classification approach applied to active UXO sites

NASA Astrophysics Data System (ADS)

Shubitidze, F.; Fernández, J. P.; Shamatava, Irma; Barrowes, B. E.; O'Neill, K.

2013-06-01

This study is designed to illustrate the discrimination performance at two UXO active sites (Oklahoma's Fort Sill and the Massachusetts Military Reservation) of a set of advanced electromagnetic induction (EMI) inversion/discrimination models which include the orthonormalized volume magnetic source (ONVMS), joint diagonalization (JD), and differential evolution (DE) approaches and whose power and flexibility greatly exceed those of the simple dipole model. The Fort Sill site is highly contaminated by a mix of the following types of munitions: 37-mm target practice tracers, 60-mm illumination mortars, 75-mm and 4.5'' projectiles, 3.5'', 2.36'', and LAAW rockets, antitank mine fuzes with and without hex nuts, practice MK2 and M67 grenades, 2.5'' ballistic windshields, M2A1-mines with/without bases, M19-14 time fuzes, and 40-mm practice grenades with/without cartridges. The site at the MMR site contains targets of yet different sizes. In this work we apply our models to EMI data collected using the MetalMapper (MM) and 2 × 2 TEMTADS sensors. The data for each anomaly are inverted to extract estimates of the extrinsic and intrinsic parameters associated with each buried target. (The latter include the total volume magnetic source or NVMS, which relates to size, shape, and material properties; the former includes location, depth, and orientation). The estimated intrinsic parameters are then used for classification performed via library matching and the use of statistical classification algorithms; this process yielded prioritized dig-lists that were submitted to the Institute for Defense Analyses (IDA) for independent scoring. The models' classification performance is illustrated and assessed based on these independent evaluations.

Targeted Antiangiogenesis Gene Therapy Using Targeted Cationic Microbubbles Conjugated with CD105 Antibody Compared with Untargeted Cationic and Neutral Microbubbles

PubMed Central

Zhou, Yu; Gu, Haitao; Xu, Yan; Li, Fan; Kuang, Shaojing; Wang, Zhigang; Zhou, Xiyuan; Ma, Huafeng; Li, Pan; Zheng, Yuanyi; Ran, Haitao; Jian, Jia; Zhao, Yajing; Song, Weixiang; Wang, Qiushi; Wang, Dong

2015-01-01

Objective This study aimed to develop targeted cationic microbubbles conjugated with a CD105 antibody (CMB105) for use in targeted vascular endothelial cell gene therapy and ultrasound imaging. We compared the results with untargeted cationic microbubbles (CMB) and neutral microbubbles (NMB). Methods CMB105 were prepared and compared with untargeted CMB and NMB. First, the microbubbles were characterized in terms of size, zeta-potential, antibody binding ability and plasmid DNA loading capacity. A tumor model of subcutaneous breast cancer in nude mice was used for our experiments. The ability of different types of microbubbles to target HUVECs in vitro and tumor neovascularization in vivo was measured. The endostatin gene was selected for its outstanding antiangiogenesis effect. For in vitro experiments, the transfection efficiency and cell cycle were analyzed using flow cytometry, and the transcription and expression of endostatin were measured by qPCR and Western blotting, respectively. Vascular tube cavity formation and tumor cell invasion were used to evaluate the antiangiogenesis gene therapy efficiency in vitro. Tumors were exposed to ultrasound irradiation with different types of microbubbles, and the gene therapy effects were investigated by detecting apoptosis induction and changes in tumor volume. Results CMB105 and CMB differed significantly from NMB in terms of zeta-potential, and the DNA loading capacities were 16.76±1.75 μg, 18.21±1.22 μg, and 0.48±0.04 μg per 5×108 microbubbles, respectively. The charge coupling of plasmid DNA to CMB105 was not affected by the presence of the CD105 antibody. Both CMB105 and CMB could target to HUVECs in vitro, whereas only CMB105 could target to tumor neovascularization in vivo. In in vitro experiments, the transfection efficiency of CMB105 was 24.7-fold higher than the transfection efficiency of NMB and 1.47-fold higher than the transfection efficiency of CMB (P<0.05). With ultrasound-targeted microbubble

Targeted antiangiogenesis gene therapy using targeted cationic microbubbles conjugated with CD105 antibody compared with untargeted cationic and neutral microbubbles.

PubMed

Zhou, Yu; Gu, Haitao; Xu, Yan; Li, Fan; Kuang, Shaojing; Wang, Zhigang; Zhou, Xiyuan; Ma, Huafeng; Li, Pan; Zheng, Yuanyi; Ran, Haitao; Jian, Jia; Zhao, Yajing; Song, Weixiang; Wang, Qiushi; Wang, Dong

2015-01-01

This study aimed to develop targeted cationic microbubbles conjugated with a CD105 antibody (CMB105) for use in targeted vascular endothelial cell gene therapy and ultrasound imaging. We compared the results with untargeted cationic microbubbles (CMB) and neutral microbubbles (NMB). CMB105 were prepared and compared with untargeted CMB and NMB. First, the microbubbles were characterized in terms of size, zeta-potential, antibody binding ability and plasmid DNA loading capacity. A tumor model of subcutaneous breast cancer in nude mice was used for our experiments. The ability of different types of microbubbles to target HUVECs in vitro and tumor neovascularization in vivo was measured. The endostatin gene was selected for its outstanding antiangiogenesis effect. For in vitro experiments, the transfection efficiency and cell cycle were analyzed using flow cytometry, and the transcription and expression of endostatin were measured by qPCR and Western blotting, respectively. Vascular tube cavity formation and tumor cell invasion were used to evaluate the antiangiogenesis gene therapy efficiency in vitro. Tumors were exposed to ultrasound irradiation with different types of microbubbles, and the gene therapy effects were investigated by detecting apoptosis induction and changes in tumor volume. CMB105 and CMB differed significantly from NMB in terms of zeta-potential, and the DNA loading capacities were 16.76±1.75 μg, 18.21±1.22 μg, and 0.48±0.04 μg per 5×10(8) microbubbles, respectively. The charge coupling of plasmid DNA to CMB105 was not affected by the presence of the CD105 antibody. Both CMB105 and CMB could target to HUVECs in vitro, whereas only CMB105 could target to tumor neovascularization in vivo. In in vitro experiments, the transfection efficiency of CMB105 was 24.7-fold higher than the transfection efficiency of NMB and 1.47-fold higher than the transfection efficiency of CMB (P<0.05). With ultrasound-targeted microbubble destruction (UTMD

Speed-up of the volumetric method of moments for the approximate RCS of large arbitrary-shaped dielectric targets

NASA Astrophysics Data System (ADS)

Moreno, Javier; Somolinos, Álvaro; Romero, Gustavo; González, Iván; Cátedra, Felipe

2017-08-01

A method for the rigorous computation of the electromagnetic scattering of large dielectric volumes is presented. One goal is to simplify the analysis of large dielectric targets with translational symmetries taken advantage of their Toeplitz symmetry. Then, the matrix-fill stage of the Method of Moments is efficiently obtained because the number of coupling terms to compute is reduced. The Multilevel Fast Multipole Method is applied to solve the problem. Structured meshes are obtained efficiently to approximate the dielectric volumes. The regular mesh grid is achieved by using parallelepipeds whose centres have been identified as internal to the target. The ray casting algorithm is used to classify the parallelepiped centres. It may become a bottleneck when too many points are evaluated in volumes defined by parametric surfaces, so a hierarchical algorithm is proposed to minimize the number of evaluations. Measurements and analytical results are included for validation purposes.

[Target and non-target screening of volatile organic compounds in industrial exhaust gas using thermal desorption-gas chromatography-mass spectrometry].

PubMed

Ma, Huilian; Jin, Jing; Li, Yun; Chen, Jiping

2017-10-08

A method of comprehensive screening of the target and non-target volatile organic compounds (VOCs) in industrial exhaust gas using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) has been developed. In this paper, two types of solid phase adsorption column were compared, and the Tenex SS TD Tube was selected. The analytes were enriched into the adsorption tube by constant flow sampling, and detected by TD-GC-MS in full scan mode. Target compounds were quantified by internal standard method, and the quantities of non-target compounds were calculated by response coefficient of toluene. The method detection limits (MDLs) for the 24 VOCs were 1.06 to 5.44 ng, and MDLs could also be expressed as 0.004 to 0.018 mg/m 3 assuming that the sampling volume was 300 mL. The average recoveries were in the range of 78.4% to 89.4% with the relative standard deviations (RSDs) of 3.9% to 14.4% ( n =7). The established analytical method was applied for the comprehensive screening of VOCs in a waste incineration power plant in Dalian city. Twenty-nine VOCs were identified. In these compounds, only five VOCs were the target compounds set in advance, which accounted for 26.7% of the total VOCs identified. Therefore, this study further proved the importance of screening non-target compounds in the analysis of VOCs in industrial exhaust gas, and has certain reference significance for the complete determination of VOCs distribution.

Are tidal volume measurements in neonatal pressure-controlled ventilation accurate?

PubMed

Chow, Lily C; Vanderhal, Andre; Raber, Jorge; Sola, Augusto

2002-09-01

Bedside pulmonary mechanics monitors (PMM) have become useful in ventilatory management in neonates. These monitors are used more frequently due to recent improvements in data-processing capabilities. PMM devices are often part of the ventilator or are separate units. The accuracy and reliability of these systems have not been carefully evaluated. We compared a single ventilatory parameter, tidal volume (V(t)), as measured by several systems. We looked at two freestanding PMMs: the Ventrak Respiratory Monitoring System (Novametrix, Wallingford, CT) and the Bicore CP-100 Neonatal Pulmonary Monitor (Allied Health Care Products, Riverside, CA), and three ventilators with built-in PMM: the VIP Bird Ventilator (Bird Products Corp., Palm Springs, CA), Siemens Servo 300A (Siemens-Elema AB, Solna, Sweden), and Drager Babylog 8000 (Drager, Inc., Chantilly, VA). A calibrated syringe (Hans Rudolph, Inc., Kansas City, MO) was used to deliver tidal volumes of 4, 10, and 20 mL to each ventilator system coupled with a freestanding PMM. After achieving steady state, six consecutive V(t) readings were taken simultaneously from the freestanding PMM and each ventilator. In a second portion of the bench study, we used pressure-control ventilation and measured exhaled tidal volume (V(te)) while ventilating a Bear Test Lung with the same three ventilators. We adjusted peak inspiratory pressure (PIP) under controlled conditions to achieve the three different targeted tidal volumes on the paired freestanding PMM. Again, six V(te) measurements were recorded for each tidal volume. Means and standard deviations were calculated.The percentage difference in measurement of V(t) delivered by calibrated syringe varied greatly, with the greatest discrepancy seen in the smallest tidal volumes, by up to 28%. In pressure control mode, V(te) as measured by the Siemens was significantly overestimated by 20-95%, with the biggest discrepancy at the smallest V(te), particularly when paired with the Bicore

Sparse PDF Volumes for Consistent Multi-Resolution Volume Rendering.

PubMed

Sicat, Ronell; Krüger, Jens; Möller, Torsten; Hadwiger, Markus

2014-12-01

This paper presents a new multi-resolution volume representation called sparse pdf volumes, which enables consistent multi-resolution volume rendering based on probability density functions (pdfs) of voxel neighborhoods. These pdfs are defined in the 4D domain jointly comprising the 3D volume and its 1D intensity range. Crucially, the computation of sparse pdf volumes exploits data coherence in 4D, resulting in a sparse representation with surprisingly low storage requirements. At run time, we dynamically apply transfer functions to the pdfs using simple and fast convolutions. Whereas standard low-pass filtering and down-sampling incur visible differences between resolution levels, the use of pdfs facilitates consistent results independent of the resolution level used. We describe the efficient out-of-core computation of large-scale sparse pdf volumes, using a novel iterative simplification procedure of a mixture of 4D Gaussians. Finally, our data structure is optimized to facilitate interactive multi-resolution volume rendering on GPUs.

Sparse PDF Volumes for Consistent Multi-Resolution Volume Rendering

PubMed Central

Sicat, Ronell; Krüger, Jens; Möller, Torsten; Hadwiger, Markus

2015-01-01

This paper presents a new multi-resolution volume representation called sparse pdf volumes, which enables consistent multi-resolution volume rendering based on probability density functions (pdfs) of voxel neighborhoods. These pdfs are defined in the 4D domain jointly comprising the 3D volume and its 1D intensity range. Crucially, the computation of sparse pdf volumes exploits data coherence in 4D, resulting in a sparse representation with surprisingly low storage requirements. At run time, we dynamically apply transfer functions to the pdfs using simple and fast convolutions. Whereas standard low-pass filtering and down-sampling incur visible differences between resolution levels, the use of pdfs facilitates consistent results independent of the resolution level used. We describe the efficient out-of-core computation of large-scale sparse pdf volumes, using a novel iterative simplification procedure of a mixture of 4D Gaussians. Finally, our data structure is optimized to facilitate interactive multi-resolution volume rendering on GPUs. PMID:26146475

Volume hologram with random encoded reference beam for secure data encryption

NASA Astrophysics Data System (ADS)

Markov, Vladimir B.; Weber, David C.; Trolinger, James D.

2000-04-01

A method is presented to store biometric and/or other important information on an ID card in the form of a Card Hologram that cannot be read or duplicated without the use of a special Key Hologram that is secured inside of an automated reader. The Key Hologram produces the unique wavefront required to release the information contained in a complex, 3D diffraction pattern recorded in a volume hologram attached to the card. Experimental results are presented in which the image of an Air Force resolution target are recorded and reconstructed in a volume material using a random speckle wavefront and that cannot be viewed using a simple wavefront such as a collimated or diverging laser beam.

VARIATION OF LUNG DEPOSITION OF MICRON SIZE PARTICLES WITH LUNG VOLUME AND BREATHING PATTERN

EPA Science Inventory

Lung volume and breathing pattern are the source of inter-and intra-subject variability of lung deposition of inhaled particles. Controlling these factors may help optimize delivery of aerosol medicine to the target site within the lung. In the present study we measured total lu...

The effect of perfluorocarbon vapour on the measurement of respiratory tidal volume during partial liquid ventilation.

PubMed

Davies, M W; Dunster, K R

2000-08-01

During partial liquid ventilation perfluorocarbon vapour is present in the exhaled gases. The volumes of these gases are measured by pneumotachometers. Error in measuring tidal volumes will give erroneous measurement of lung compliance during partial liquid ventilation. We aim to compare measured tidal volumes with and without perfluorocarbon vapour using tidal volumes suitable for use in neonates. Tidal volumes were produced with a 100 ml calibration syringe from 20 to 100 ml and with a calibrated Harvard rodent ventilator from 2.5 to 20 ml. Control tidal volumes were drawn from a humidifier chamber containing water vapour and the PFC tidal volumes were drawn from a humidifier chamber containing water and perfluorocarbon (FC-77) vapour. Tidal volumes were measured by a fixed orifice, target, differential pressure flowmeter (VenTrak) or a hot-wire anenometer (Bear Cub) placed between the calibration syringe or ventilator and the humidifier chamber. All tidal volumes measured with perfluorocarbon vapour were increased compared with control (ANOVA p < 0.001 and post t-test p < 0.0001). Measured tidal volume increased from 7 to 16% with the fixed orifice type flow-meter, and from 35 to 41% with the hot-wire type. In conclusion, perfluorocarbon vapour flowing through pneumotachometers gives falsely high tidal volume measurements. Calculation of lung compliance must take into account the effect of perfluorocarbon vapour on the measurement of tidal volume.

Endocervical ultrasound applicator for integrated hyperthermia and HDR brachytherapy in the treatment of locally advanced cervical carcinoma.

PubMed

Wootton, Jeffery H; Hsu, I-Chow Joe; Diederich, Chris J

2011-02-01

The clinical success of hyperthermia adjunct to radiotherapy depends on adequate temperature elevation in the tumor with minimal temperature rise in organs at risk. Existing technologies for thermal treatment of the cervix have limited spatial control or rapid energy falloff. The objective of this work is to develop an endocervical applicator using a linear array of multisectored tubular ultrasound transducers to provide 3-D conformal, locally targeted hyperthermia concomitant to radiotherapy in the uterine cervix. The catheter-based device is integrated within a HDR brachytherapy applicator to facilitate sequential and potentially simultaneous heat and radiation delivery. Treatment planning images from 35 patients who underwent HDR brachytherapy for locally advanced cervical cancer were inspected to assess the dimensions of radiation clinical target volumes (CTVs) and gross tumor volumes (GTVs) surrounding the cervix and the proximity of organs at risk. Biothermal simulation was used to identify applicator and catheter material parameters to adequately heat the cervix with minimal thermal dose accumulation in nontargeted structures. A family of ultrasound applicators was fabricated with two to three tubular transducers operating at 6.6-7.4 MHz that are unsectored (360 degrees), bisectored (2 x 180 degrees), or trisectored (3 x 120 degrees) for control of energy deposition in angle and along the device length in order to satisfy anatomical constraints. The device is housed in a 6 mm diameter PET catheter with cooling water flow for endocervical implantation. Devices were characterized by measuring acoustic efficiencies, rotational acoustic intensity distributions, and rotational temperature distributions in phantom. The CTV in HDR brachytherapy plans extends 20.5 +/- 5.0 mm from the endocervical tandem with the rectum and bladder typically <8 mm from the target boundary. The GTV extends 19.4 +/- 7.3 mm from the tandem. Simulations indicate that for 60 min

Envisaging bacteria as phage targets

PubMed Central

Abedon, Stephen T.

2011-01-01

It can be difficult to appreciate just how small bacteria and phages are or how large, in comparison, the volumes that they occupy. A single milliliter, for example, can represent to a phage what would be, with proper scaling, an “ocean” to you and me. Here I illustrate, using more easily visualized macroscopic examples, the difficulties that a phage, as a randomly diffusing particle, can have in locating bacteria to infect. I conclude by restating the truism that the rate of phage adsorption to a given target bacterium is a function of phage density, that is, titer, in combination with the degree of bacterial susceptibility to adsorption by an encountering phage. PMID:23616932

How Actuated Particles Effectively Capture Biomolecular Targets

PubMed Central

2017-01-01

Because of their high surface-to-volume ratio and adaptable surface functionalization, particles are widely used in bioanalytical methods to capture molecular targets. In this article, a comprehensive study is reported of the effectiveness of protein capture by actuated magnetic particles. Association rate constants are quantified in experiments as well as in Brownian dynamics simulations for different particle actuation configurations. The data reveal how the association rate depends on the particle velocity, particle density, and particle assembly characteristics. Interestingly, single particles appear to exhibit target depletion zones near their surface, caused by the high density of capture molecules. The depletion effects are even more limiting in cases with high particle densities. The depletion effects are overcome and protein capture rates are enhanced by applying dynamic particle actuation, resulting in an increase in the association rate constants by up to 2 orders of magnitude. PMID:28192952

Target-locking acquisition with real-time confocal (TARC) microscopy.

PubMed

Lu, Peter J; Sims, Peter A; Oki, Hidekazu; Macarthur, James B; Weitz, David A

2007-07-09

We present a real-time target-locking confocal microscope that follows an object moving along an arbitrary path, even as it simultaneously changes its shape, size and orientation. This Target-locking Acquisition with Realtime Confocal (TARC) microscopy system integrates fast image processing and rapid image acquisition using a Nipkow spinning-disk confocal microscope. The system acquires a 3D stack of images, performs a full structural analysis to locate a feature of interest, moves the sample in response, and then collects the next 3D image stack. In this way, data collection is dynamically adjusted to keep a moving object centered in the field of view. We demonstrate the system's capabilities by target-locking freely-diffusing clusters of attractive colloidal particles, and activelytransported quantum dots (QDs) endocytosed into live cells free to move in three dimensions, for several hours. During this time, both the colloidal clusters and live cells move distances several times the length of the imaging volume.

Genetically targeted 3D visualisation of Drosophila neurons under Electron Microscopy and X-Ray Microscopy using miniSOG

PubMed Central

Ng, Julian; Browning, Alyssa; Lechner, Lorenz; Terada, Masako; Howard, Gillian; Jefferis, Gregory S. X. E.

2016-01-01

Large dimension, high-resolution imaging is important for neural circuit visualisation as neurons have both long- and short-range patterns: from axons and dendrites to the numerous synapses at terminal endings. Electron Microscopy (EM) is the favoured approach for synaptic resolution imaging but how such structures can be segmented from high-density images within large volume datasets remains challenging. Fluorescent probes are widely used to localise synapses, identify cell-types and in tracing studies. The equivalent EM approach would benefit visualising such labelled structures from within sub-cellular, cellular, tissue and neuroanatomical contexts. Here we developed genetically-encoded, electron-dense markers using miniSOG. We demonstrate their ability in 1) labelling cellular sub-compartments of genetically-targeted neurons, 2) generating contrast under different EM modalities, and 3) segmenting labelled structures from EM volumes using computer-assisted strategies. We also tested non-destructive X-ray imaging on whole Drosophila brains to evaluate contrast staining. This enabled us to target specific regions for EM volume acquisition. PMID:27958322

Is the Ellipsoid Formula the New Standard for 3-Tesla MRI Prostate Volume Calculation without Endorectal Coil?

PubMed

Haas, Matthias; Günzel, Karsten; Miller, Kurt; Hamm, Bernd; Cash, Hannes; Asbach, Patrick

2017-01-01

Prostate volume in multiparametric MRI (mpMRI) is of clinical importance. For 3-Tesla mpMRI without endorectal coil, there is no distinctive standard for volume calculation. We tested the accuracy of the ellipsoid formula with planimetric volume measurements as reference and investigated the correlation of gland volume and cancer detection rate on MRI/ultrasound (MRI/US) fusion-guided biopsy. One hundred forty-three patients with findings on 3-Tesla mpMRI suspicious of cancer and subsequent MRI/US fusion-guided targeted biopsy and additional systematic biopsy were analyzed. T2-weighted images were used for measuring the prostate diameters and for planimetric volume measurement by a segmentation software. Planimetric and calculated prostate volumes were compared with clinical data. The median prostate volume was 48.1 ml (interquartile range (IQR) 36.9-62.1 ml). Volume calculated by the ellipsoid formula showed a strong concordance with planimetric volume, with a tendency to underestimate prostate volume (median volume 43.1 ml (IQR 31.2-58.8 ml); r = 0.903, p < 0.001). There was a moderate, significant inverse correlation of prostate volume to a positive biopsy result (r = -0.24, p = 0.004). The ellipsoid formula gives sufficient approximation of prostate volume on 3-Tesla mpMRI without endorectal coil. It allows a fast, valid volume calculation in prostate MRI datasets. © 2016 S. Karger AG, Basel.

Novel GABA receptor pesticide targets.

PubMed

Casida, John E; Durkin, Kathleen A

2015-06-01

The γ-aminobutyric acid (GABA) receptor has four distinct but overlapping and coupled targets of pesticide action importantly associated with little or no cross-resistance. The target sites are differentiated by binding assays with specific radioligands, resistant strains, site-directed mutagenesis and molecular modeling. Three of the targets are for non-competitive antagonists (NCAs) or channel blockers of widely varied chemotypes. The target of the first generation (20th century) NCAs differs between the larger or elongated compounds (NCA-IA) including many important insecticides of the past (cyclodienes and polychlorocycloalkanes) or present (fiproles) and the smaller or compact compounds (NCA-IB) highly toxic to mammals and known as cage convulsants, rodenticides or chemical threat agents. The target of greatest current interest is designated NCA-II for the second generation (21st century) of NCAs consisting for now of isoxazolines and meta-diamides. This new and uniquely different NCA-II site apparently differs enough between insects and mammals to confer selective toxicity. The fourth target is the avermectin site (AVE) for allosteric modulators of the chloride channel. NCA pesticides vary in molecular surface area and solvent accessible volume relative to avermectin with NCA-IBs at 20-22%, NCA-IAs at 40-45% and NCA-IIs at 57-60%. The same type of relationship relative to ligand-docked length is 27-43% for NCA-IBs, 63-71% for NCA-IAs and 85-105% for NCA-IIs. The four targets are compared by molecular modeling for the Drosophila melanogaster GABA-R. The principal sites of interaction are proposed to be: pore V1' and A2' for NCA-IB compounds; pore A2', L6' and T9' for NCA-IA compounds; pore T9' to S15' in proximity to M1/M3 subunit interface (or alternatively an interstitial site) for NCA-II compounds; and M1/M3, M2 interfaces for AVE. Understanding the relationships of these four binding sites is important in resistance management and in the discovery and use

Feasibility of Pathology-Correlated Lung Imaging for Accurate Target Definition of Lung Tumors

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

Stroom, Joep; Blaauwgeers, Hans; Baardwijk, Angela van

2007-09-01

Purpose: To accurately define the gross tumor volume (GTV) and clinical target volume (GTV plus microscopic disease spread) for radiotherapy, the pretreatment imaging findings should be correlated with the histopathologic findings. In this pilot study, we investigated the feasibility of pathology-correlated imaging for lung tumors, taking into account lung deformations after surgery. Methods and Materials: High-resolution multislice computed tomography (CT) and positron emission tomography (PET) scans were obtained for 5 patients who had non-small-cell lung cancer (NSCLC) before lobectomy. At the pathologic examination, the involved lung lobes were inflated with formalin, sectioned in parallel slices, and photographed, and microscopic sectionsmore » were obtained. The GTVs were delineated for CT and autocontoured at the 42% PET level, and both were compared with the histopathologic volumes. The CT data were subsequently reformatted in the direction of the macroscopic sections, and the corresponding fiducial points in both images were compared. Hence, the lung deformations were determined to correct the distances of microscopic spread. Results: In 4 of 5 patients, the GTV{sub CT} was, on average, 4 cm{sup 3} ({approx}53%) too large. In contrast, for 1 patient (with lymphangitis carcinomatosa), the GTV{sub CT} was 16 cm{sup 3} ({approx}40%) too small. The GTV{sub PET} was too small for the same patient. Regarding deformations, the volume of the well-inflated lung lobes on pathologic examination was still, on average, only 50% of the lobe volume on CT. Consequently, the observed average maximal distance of microscopic spread (5 mm) might, in vivo, be as large as 9 mm. Conclusions: Our results have shown that pathology-correlated lung imaging is feasible and can be used to improve target definition. Ignoring deformations of the lung might result in underestimation of the microscopic spread.« less

Comparison of pencil beam–based homogeneous vs inhomogeneous target dose planning for stereotactic body radiotherapy of peripheral lung tumors through Monte Carlo–based recalculation

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

Ohtakara, Kazuhiro, E-mail: ohtakara@murakami.asahi-u.ac.jp; Hoshi, Hiroaki

2015-10-01

This study was conducted to ascertain whether homogeneous target dose planning is suitable for stereotactic body radiotherapy (SBRT) of peripheral lung cancer under appropriate breath-holding. For 20 peripheral lung tumors, paired dynamic conformal arc plans were generated by only adjusting the leaf margin to the planning target volume (PTV) edge for fulfilling the conditions such that the prescription isodose surface (IDS) encompassing exactly 95% of the PTV (PTV D{sub 95}) corresponds to 95% and 80% IDS, normalized to 100% at the PTV isocenter under a pencil beam (PB) algorithm with radiologic path length correction. These plans were recalculated using themore » x-ray voxel Monte Carlo (XVMC) algorithm under otherwise identical conditions, and then compared. Lesions abutting the parietal pleura or not were defined as edge or island tumors, respectively, and the influences of the target volume and its location relative to the chest wall on the target dose were examined. The median (range) leaf margin required for the 95% and 80% plans was 3.9 mm (1.3 to 5.0) and −1.2 mm (−1.8 to 0.1), respectively. Notably, the latter was significantly correlated negatively with PTV. In the 80% plans, the PTV D{sub 95} was slightly higher under XVMC, whereas the PTV D{sub 98} was significantly lower, irrespective of the dose calculation algorithm used. Other PTV and all gross tumor volume doses were significantly higher, while the lung doses outside the PTV were slightly lower. The target doses increased as a function of PTV and were significantly lower for island tumors than for edge tumors. In conclusion, inhomogeneous target dose planning using smaller leaf margin for a larger tumor volume was deemed suitable in ensuring more sufficient target dose while slightly reducing lung dose. In addition, more inhomogeneous target dose planning using <80% IDS (e.g., 70%) for PTV covering would be preferable for island tumors.« less

Pressure control of a proton beam-irradiated water target through an internal flow channel-induced thermosyphon.

PubMed

Hong, Bong Hwan; Jung, In Su

2017-07-01

A water target was designed to enhance cooling efficiency using a thermosyphon, which is a system that uses natural convection to induce heat exchange. Two water targets were fabricated: a square target without any flow channel and a target with a flow channel design to induce a thermosyphon mechanism. These two targets had the same internal volume of 8 ml. First, visualization experiments were performed to observe the internal flow by natural convection. Subsequently, an experiment was conducted to compare the cooling performance of both water targets by measuring the temperature and pressure. A 30-MeV proton beam with a beam current of 20 μA was used to irradiate both targets. Consequently, the target with an internal flow channel had a lower mean temperature and a 50% pressure drop compared to the target without a flow channel during proton beam irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pertinent anatomy and analysis for midface volumizing procedures.

PubMed

Surek, Christopher C; Beut, Javier; Stephens, Robert; Jelks, Glenn; Lamb, Jerome

2015-05-01

The study was conducted to construct an anatomically inspired midfacial analysis facilitating safe, accurate, and dynamic nonsurgical rejuvenation. Emphasis is placed on determining injection target areas and adverse event zones. Twelve hemifacial fresh cadavers were dissected in a layered fashion. Dimensional measurements between the midfacial fat compartments, prezygomatic space, mimetic muscles, and neurovascular bundles were used to develop a topographic analysis for clinical injections. A longitudinal line from the base of the alar crease to the medial edge of the levator anguli oris muscle (1.9 cm), lateral edge of the levator anguli oris muscle (2.6 cm), and zygomaticus major muscle (4.6 cm) partitions the cheek into two aesthetic regions. A six-step facial analysis outlines three target zones and two adverse event zones and triangulates the point of maximum cheek projection. The lower adverse event zone yields an anatomical explanation to inadvertent jowling during anterior cheek injection. The upper adverse event zone localizes the palpebral branch of the infraorbital artery. The medial malar target area isolates quadrants for anterior cheek projection and tear trough effacement. The middle malar target area addresses lid-cheek blending and superficial compartment turgor. The lateral malar target area highlights lateral cheek projection and locates the prezygomatic space. This stepwise analysis illustrates target areas and adverse event zones to achieve midfacial support, contour, and profile in the repose position and simultaneous molding of a natural shape during animation. This reproducible method can be used both procedurally and in record-keeping for midface volumizing procedures.

[Clinical evaluation of heavy-particle radiotherapy using dose volume histogram (DVH)].

PubMed

Terahara, A; Nakano, T; Tsujii, H

1998-01-01

Radiotherapy with heavy particles such as proton and heavy-charged particles is a promising modality for treatment of localized malignant tumors because of the good dose distribution. A dose calculation and radiotherapy planning system which is essential for this kind of treatment has been developed in recent years. It has the capability to compute the dose volume histogram (DVH) which contains dose-volume information for the target volume and other interesting volumes. Recently, DVH is commonly used to evaluate and compare dose distributions in radiotherapy with both photon and heavy particles, and it shows that a superior dose distribution is obtained in heavy particle radiotherapy. DVH is also utilized for the evaluation of dose distribution related to clinical outcomes. Besides models such as normal tissue complication probability (NTCP) and tumor control probability (TCP), which can be calculated from DVH are proposed by several authors, they are applied to evaluate dose distributions themselves and to evaluate them in relation to clinical results. DVH is now a useful and important tool, but further studies are needed to use DVH and these models practically for clinical evaluation of heavy-particle radiotherapy.

Preliminary investigations on the use of uranium silicide targets for fission Mo-99 production

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

Cols, H.; Cristini, P.; Marques, R.

1997-08-01

The National Atomic Energy Commission (CNEA) of Argentine Republic owns and operates an installation for production of molybdenum-99 from fission products since 1985, and, since 1991, covers the whole national demand of this nuclide, carrying out a program of weekly productions, achieving an average activity of 13 terabecquerel per week. At present they are finishing an enlargement of the production plant that will allow an increase in the volume of production to about one hundred of terabecquerel. Irradiation targets are uranium/aluminium alloy with 90% enriched uranium with aluminium cladding. In view of international trends held at present for replacing highmore » enrichment uranium (HEU) for enrichment values lower than 20 % (LEU), since 1990 the authors are in contact with the RERTR program, beginning with tests to adapt their separation process to new irradiation target conditions. Uranium silicide (U{sub 3}Si{sub 2}) was chosen as the testing material, because it has an uranium mass per volume unit, so that it allows to reduce enrichment to a value of 20%. CNEA has the technology for manufacturing miniplates of uranium silicide for their purposes. In this way, equivalent amounts of Molybdenum-99 could be obtained with no substantial changes in target parameters and irradiation conditions established for the current process with Al/U alloy. This paper shows results achieved on the use of this new target.« less

The National Spallation Neutron Source Target Station.

NASA Astrophysics Data System (ADS)

Gabriel, T. A.

1997-05-01

The technologies that are being utilized to design and build a state-of-the-art high powered (>= 1 MW), short pulsed (<= 1 μsec), and reliable spallation neutron source target station are discussed. The protons which directly and indirectly produce the neutrons will be obtained from a 1 GeV proton accelerator composed of an ion gun, rfq, linac, and storage ring. Many scientific and technical disciplines are required to produce a successful target station. These disciplines include engineering, remote handling, neutronics, materials, thermal hydraulics, shock analysis, etc. In the areas of engineering and remote handling special emphasis is being given to rapid and efficient assembly and disassembly of critical parts of the target station. In the neutronics area, emphasis is being given to neutron yield and pulse optimization from the moderators, and heating and activation rates throughout the station. Development of structural materials to withstand aggressive radiation environments and that are compatible with other materials is also an important area. Thermal hydraulics and shock analysis are being closely studied since large amounts of energy are being deposited in small volumes in relatively short time periods (< 1 μsec). These areas will be expanded upon in the paper.

Reading, writing, and reserve: Literacy activities are linked to hippocampal volume and memory in multiple sclerosis.

PubMed

Sumowski, James F; Rocca, Maria A; Leavitt, Victoria M; Riccitelli, Gianna; Meani, Alessandro; Comi, Giancarlo; Filippi, Massimo

2016-10-01

Engagement in cognitive leisure activities during early adulthood has been linked to preserved memory and larger hippocampal volume in persons with multiple sclerosis (MS). To investigate which specific types of cognitive leisure activities contribute to hippocampal volume and memory. We investigated links between three types of cognitive activities (Reading-Writing, Art-Music, Games-Hobbies) and (a) hippocampal volume within independent samples of Italian (n=187) and American (n=55) MS patients and (b) memory in subsamples of Italian (n=97) and American (n=53) patients. Reading-Writing was the only predictor of hippocampal volume (rp=.204, p=.002), and the best predictor of memory (rp=.288, p=.001). Findings inform the development of targeted evidence-based enrichment programs aiming to bolster reserve against memory decline. © The Author(s), 2016.

Predicting uncertainty in future marine ice sheet volume using Bayesian statistical methods

NASA Astrophysics Data System (ADS)

Davis, A. D.

2015-12-01

The marine ice instability can trigger rapid retreat of marine ice streams. Recent observations suggest that marine ice systems in West Antarctica have begun retreating. However, unknown ice dynamics, computationally intensive mathematical models, and uncertain parameters in these models make predicting retreat rate and ice volume difficult. In this work, we fuse current observational data with ice stream/shelf models to develop probabilistic predictions of future grounded ice sheet volume. Given observational data (e.g., thickness, surface elevation, and velocity) and a forward model that relates uncertain parameters (e.g., basal friction and basal topography) to these observations, we use a Bayesian framework to define a posterior distribution over the parameters. A stochastic predictive model then propagates uncertainties in these parameters to uncertainty in a particular quantity of interest (QoI)---here, the volume of grounded ice at a specified future time. While the Bayesian approach can in principle characterize the posterior predictive distribution of the QoI, the computational cost of both the forward and predictive models makes this effort prohibitively expensive. To tackle this challenge, we introduce a new Markov chain Monte Carlo method that constructs convergent approximations of the QoI target density in an online fashion, yielding accurate characterizations of future ice sheet volume at significantly reduced computational cost.Our second goal is to attribute uncertainty in these Bayesian predictions to uncertainties in particular parameters. Doing so can help target data collection, for the purpose of constraining the parameters that contribute most strongly to uncertainty in the future volume of grounded ice. For instance, smaller uncertainties in parameters to which the QoI is highly sensitive may account for more variability in the prediction than larger uncertainties in parameters to which the QoI is less sensitive. We use global sensitivity

Radioiodine therapy in Graves' disease based on tissue-absorbed dose calculations: effect of pre-treatment thyroid volume on clinical outcome.

PubMed

Reinhardt, Michael J; Brink, Ingo; Joe, Alexius Y; Von Mallek, Dirk; Ezziddin, Samer; Palmedo, Holger; Krause, Thomas M

2002-09-01

This study was performed with three aims. The first was to analyse the effectiveness of radioiodine therapy in Graves' disease patients with and without goitres under conditions of mild iodine deficiency using several tissue-absorbed doses. The second aim was to detect further parameters which might be predictive for treatment outcome. Finally, we wished to determine the deviation of the therapeutically achieved dose from that intended. Activities of 185-2,220 MBq radioiodine were calculated by means of Marinelli's formula to deliver doses of 150, 200 or 300 Gy to the thyroids of 224 patients with Graves' disease and goitres up to 130 ml in volume. Control of hyperthyroidism, change in thyroid volume and thyrotropin-receptor antibodies were evaluated 15+/-9 months after treatment for each dose. The results were further evaluated with respect to pre-treatment parameters which might be predictive for therapy outcome. Thyroidal radioiodine uptake was measured every day during therapy to determine the therapeutically achieved target dose and its coefficient of variation. There was a significant dose dependency in therapeutic outcome: frequency of hypothyroidism increased from 27.4% after 150 Gy to 67.7% after 300 Gy, while the frequency of persistent hyperthyroidism decreased from 27.4% after 150 Gy to 8.1% after 300 Gy. Patients who became hypothyroid had a maximum thyroid volume of 42 ml and received a target dose of 256+/-80 Gy. The coefficient of variation for the achieved target dose ranged between 27.7% for 150 Gy and 17.8% for 300 Gy. When analysing further factors which might influence therapeutic outcome, only pre-treatment thyroid volume showed a significant relationship to the result of treatment. It is concluded that a target dose of 250 Gy is essential to achieve hypothyroidism within 1 year after radioiodine therapy in Graves' disease patients with goitres up to 40 ml in volume. Patients with larger goitres might need higher doses.

Imaging Ca2+ nanosparks in heart with a new targeted biosensor.

PubMed

Shang, Wei; Lu, Fujian; Sun, Tao; Xu, Jiejia; Li, Lin-Lin; Wang, Yanru; Wang, Gang; Chen, Liangyi; Wang, Xianhua; Cannell, Mark B; Wang, Shi-Qiang; Cheng, Heping

2014-01-31

In cardiac dyads, junctional Ca2+ directly controls the gating of the ryanodine receptors (RyRs), and is itself dominated by RyR-mediated Ca2+ release from the sarcoplasmic reticulum. Existing probes do not report such local Ca2+ signals because of probe diffusion, so a junction-targeted Ca2+ sensor should reveal new information on cardiac excitation-contraction coupling and its modification in disease states. To investigate Ca2+ signaling in the nanoscopic space of cardiac dyads by targeting a new sensitive Ca2+ biosensor (GCaMP6f) to the junctional space. By fusing GCaMP6f to the N terminus of triadin 1 or junctin, GCaMP6f-triadin 1/junctin was targeted to dyadic junctions, where it colocalized with t-tubules and RyRs after adenovirus-mediated gene transfer. This membrane protein-tagged biosensor displayed ≈4× faster kinetics than native GCaMP6f. Confocal imaging revealed junctional Ca2+ transients (Ca2+ nanosparks) that were ≈50× smaller in volume than conventional Ca2+ sparks (measured with diffusible indicators). The presence of the biosensor did not disrupt normal Ca2+ signaling. Because no indicator diffusion occurred, the amplitude and timing of release measurements were improved, despite the small recording volume. We could also visualize coactivation of subclusters of RyRs within a single junctional region, as well as quarky Ca2+ release events. This new, targeted biosensor allows selective visualization and measurement of nanodomain Ca2+ dynamics in intact cells and can be used to give mechanistic insights into dyad RyR operation in health and in disease states such as when RyRs become orphaned.

Impact of Volume Management on Volume Overload and Rehospitalization in CAPD Patients.

PubMed

Xu, Yi; Yang, Shen-Min; Wang, Xiao-Hua; Wang, Hai-Fang; Niu, Mei-E; Yang, Yi-Qun; Lu, Guo-Yuan; Pang, Jian-Hong; Wang, Fei; Li, Lin

2018-05-01

Heart failure due to volume overload is a major reason for rehospitalization in continuous ambulatory peritoneal dialysis patients. Strict volume control provides better cardiac functions and blood pressure in this population. Volume management, which is a volume control strategy, may decrease volume overload and related complications. Using a quasi-experimental design, 66 continuous ambulatory peritoneal dialysis patients were randomly assigned to the intervention group ( n = 34) and control group ( n = 32). The patients were followed up for 6 months with scheduled clinic and/or telephone visits; the intervention group adopted volume management strategy, while the control group adopted conventional care. Volume overload and cardiac function were compared between the two groups at the baseline and at 6 months. At Month 6, the intervention group resulted in significant improvement in volume overloaded status, cardiac function, and volume-overload-related rehospitalization. Volume management strategy allows for better control of volume overload and is associated with fewer volume-related readmissions.

The Voronoi volume and molecular representation of molar volume: equilibrium simple fluids.

PubMed

Hunjan, Jagtar Singh; Eu, Byung Chan

2010-04-07

The Voronoi volume of simple fluids was previously made use of in connection with volume transport phenomena in nonequilibrium simple fluids. To investigate volume transport phenomena, it is important to develop a method to compute the Voronoi volume of fluids in nonequilibrium. In this work, as a first step to this goal, we investigate the equilibrium limit of the nonequilibrium Voronoi volume together with its attendant related molar (molal) and specific volumes. It is proved that the equilibrium Voronoi volume is equivalent to the molar (molal) volume. The latter, in turn, is proved equivalent to the specific volume. This chain of equivalences provides an alternative procedure of computing the equilibrium Voronoi volume from the molar volume/specific volume. We also show approximate methods of computing the Voronoi and molar volumes from the information on the pair correlation function. These methods may be employed for their quick estimation, but also provide some aspects of the fluid structure and its relation to the Voronoi volume. The Voronoi volume obtained from computer simulations is fitted to a function of temperature and pressure in the region above the triple point but below the critical point. Since the fitting function is given in terms of reduced variables for the Lennard-Jones (LJ) model and the kindred volumes (i.e., specific and molar volumes) are in essence equivalent to the equation of state, the formula obtained is a reduced equation state for simple fluids obeying the LJ model potential in the range of temperature and pressure examined and hence can be used for other simple fluids.

Conformal and intensity modulated irradiation of head and neck cancer: the potential for improved target irradiation, salivary gland function, and quality of life.

PubMed

Eisbruch, A; Dawson, L A; Kim, H M; Bradford, C R; Terrell, J E; Chepeha, D B; Teknos, T N; Anzai, Y; Marsh, L H; Martel, M K; Ten Haken, R K; Wolf, G T; Ship, J A

1999-01-01

To develop techniques which facilitate sparing of the major salivary glands while adequately treating the targets in patients requiring comprehensive bilateral neck irradiation (RT). Conformal and static, multisegmental intensity modulated (IMRT) techniques have been developed. The salivary flow rates before and periodically after RT have been measured selectively from each major salivary gland and the residual flows correlated with glands' dose volume histograms. Subjective xerostomia questionnaires have been developed and validated. The pattern of local-regional recurrences has been examined using CT scans at the time of recurrence, transferring the recurrence volumes to the planning CT scans and regenerating the dose distributions at the recurrence sites. Target coverage and dose homogeneity in IMRT treatment plans were found to be significantly better than standard RT plans. Significant parotid gland sparing was achieved. The relationships among dose, irradiated volume and saliva flow rates from the parotid glands were characterized by dose and volume thresholds. A mean dose of 26 Gy was found to be the threshold for stimulated saliva. Subjective xerostomia was significantly reduced in patients irradiated with parotid sparing techniques, compared to patients with similar tumors treated with standard RT. The large majority of recurrences occurred inside high-risk targets. Tangible gains in salivary gland sparing and target coverage are being achieved and an improvement in some measures of quality of life is suggested by our findings. A mean parotid gland dose of < or = 26 Gy should be a planning objective if significant parotid function preservation is desired. The pattern of recurrence suggests that careful escalation of the dose to targets judged to be at highest risk may improve tumor control.

Optimal volume of injectate for fluoroscopy-guided cervical interlaminar epidural injection in patients with neck and upper extremity pain

PubMed Central

Park, Jun Young; Kim, Doo Hwan; Lee, Kunhee; Choi, Seong-Soo; Leem, Jeong-Gil

2016-01-01

Abstract There is no study of optimal volume of contrast medium to use in cervical interlaminar epidural injections (CIEIs) for appropriate spread to target lesions. To determine optimal volume of contrast medium to use in CIEIs. We analyzed the records of 80 patients who had undergone CIEIs. Patients were divided into 3 groups according to the amount of contrast: 3, 4.5, and 6 mL. The spread of medium to the target level was analyzed. Numerical rating scale data were also analyzed. The dye had spread to a point above the target level in 15 (78.9%), 22 (84.6%), and 32 (91.4%) patients in groups 1 to 3, respectively. The dye reached both sides in 14 (73.7%), 18 (69.2%), and 23 (65.7%) patients, and reached the ventral epidural space in 15 (78.9%), 22 (84.6%), and 30 (85.7%) patients, respectively. There were no significant differences of contrast spread among the groups. There were no significant differences in the numerical rating scale scores among the groups during the 3 months. When performing CIEIs, 3 mL medication is sufficient volume for the treatment of neck and upper-extremity pain induced by lower cervical degenerative disease. PMID:27787378

Optimal volume of injectate for fluoroscopy-guided cervical interlaminar epidural injection in patients with neck and upper extremity pain.

PubMed

Park, Jun Young; Kim, Doo Hwan; Lee, Kunhee; Choi, Seong-Soo; Leem, Jeong-Gil

2016-10-01

There is no study of optimal volume of contrast medium to use in cervical interlaminar epidural injections (CIEIs) for appropriate spread to target lesions. To determine optimal volume of contrast medium to use in CIEIs. We analyzed the records of 80 patients who had undergone CIEIs. Patients were divided into 3 groups according to the amount of contrast: 3, 4.5, and 6 mL. The spread of medium to the target level was analyzed. Numerical rating scale data were also analyzed. The dye had spread to a point above the target level in 15 (78.9%), 22 (84.6%), and 32 (91.4%) patients in groups 1 to 3, respectively. The dye reached both sides in 14 (73.7%), 18 (69.2%), and 23 (65.7%) patients, and reached the ventral epidural space in 15 (78.9%), 22 (84.6%), and 30 (85.7%) patients, respectively. There were no significant differences of contrast spread among the groups. There were no significant differences in the numerical rating scale scores among the groups during the 3 months. When performing CIEIs, 3 mL medication is sufficient volume for the treatment of neck and upper-extremity pain induced by lower cervical degenerative disease.

Effects of breathing pattern and inspired air conditions on breath condensate volume, pH, nitrite, and protein concentrations.

PubMed

McCafferty, J B; Bradshaw, T A; Tate, S; Greening, A P; Innes, J A

2004-08-01

The effects of breathing pattern and inspired air conditions on the volume and content of exhaled breath condensate (EBC) were investigated. Total exhaled water (TEW), EBC volume, pH, nitrite and protein concentrations were measured in three groups of 10 healthy subjects breathing into a condenser at different target minute ventilations (Vm), tidal volumes (Vt), and inspired air conditions. The volumes of both TEW and EBC increased significantly with Vm. For Vm 7.5, 15 and 22.5 l/min, mean (SD) EBC was 627 (258) microl, 1019 (313) microl, and 1358 (364) microl, respectively (p<0.001) and TEW was 1879 (378) microl, 2986 (496) microl, and 4679 (700) microl, respectively (p<0.001). TEW was significantly higher than EBC, reflecting a condenser efficiency of 40% at a target Vm of 7.5 l/min which reduced to 29% at Vm 22.5 l/min. Lower Vt gave less TEW than higher Vt (26.6 v 30.7 microl/l, mean difference 4.1 (95% CI 2.6 to 5.6), p<0.001) and a smaller EBC volume (4.3 v 7.6 microl/l, mean difference 3.4 (95% CI 2.3 to 4.5), p<0.001). Cooler and drier inspired air yielded less water vapour and less breath condensate than standard conditions (p<0.05). Changes in the breathing pattern had no effect on EBC protein and nitrite concentrations and pH. These results show that condensate volume can be increased by using high Vt and increased Vm without compromising the dilution of the sample.

Total target volume is a better predictor of whole brain dose from gamma stereotactic radiosurgery than the number, shape, or location of the lesions

PubMed Central

Narayanasamy, Ganesh; Smith, Adam; Van Meter, Emily; McGarry, Ronald; Molloy, Janelle A.

2013-01-01

Purpose: To assess the hypothesis that the volume of whole brain that receives a certain dose level is primarily dependent on the treated volume rather than on the number, shape, or location of the lesions. This would help a physician validate the suitability of GammaKnife® based stereotactic radiosurgery (GKSR) prior to treatment. Methods: Simulation studies were performed to establish the hypothesis for both oblong and spherical shaped lesions of various numbers and sizes. Forty patients who underwent GKSR [mean age of 54 years (range 7–80), mean number of lesions of 2.5 (range 1–6), and mean lesion volume of 4.4 cm3 (range 0.02–22.2 cm3)] were also studied retrospectively. Following recommendations of QUANTEC, the volume of brain irradiated by the 12 Gy (VB12) isodose line was measured and a power-law based relation is proposed here for estimating VB12 from the known tumor volume and the prescription dose. Results: In the simulation study on oblong, spherical, and multiple lesions, the volume of brain irradiated by 50%, 10%, and 1% of maximum dose was found to have linear, linear, and exponentially increasing dependence on the volume of the treated region, respectively. In the retrospective study on 40 GKSR patients, a similar relationship was found to predict the brain dose with a Spearman correlation coefficient >0.9. In both the studies, the volume of brain irradiated by a certain dose level does not have a statistically significant relationship (p ≥ 0.05) with the number, shape, or position of the lesions. The measured VB12 agrees with calculation to within 1.7%. Conclusions: The results from the simulation and the retrospective clinical studies indicate that the volume of whole brain that receives a certain percentage of the maximum dose is primarily dependent on the treated volume and less on the number, shape, and location of the lesions. PMID:24007147

Development of automatic visceral fat volume calculation software for CT volume data.

PubMed

Nemoto, Mitsutaka; Yeernuer, Tusufuhan; Masutani, Yoshitaka; Nomura, Yukihiro; Hanaoka, Shouhei; Miki, Soichiro; Yoshikawa, Takeharu; Hayashi, Naoto; Ohtomo, Kuni

2014-01-01

To develop automatic visceral fat volume calculation software for computed tomography (CT) volume data and to evaluate its feasibility. A total of 24 sets of whole-body CT volume data and anthropometric measurements were obtained, with three sets for each of four BMI categories (under 20, 20 to 25, 25 to 30, and over 30) in both sexes. True visceral fat volumes were defined on the basis of manual segmentation of the whole-body CT volume data by an experienced radiologist. Software to automatically calculate visceral fat volumes was developed using a region segmentation technique based on morphological analysis with CT value threshold. Automatically calculated visceral fat volumes were evaluated in terms of the correlation coefficient with the true volumes and the error relative to the true volume. Automatic visceral fat volume calculation results of all 24 data sets were obtained successfully and the average calculation time was 252.7 seconds/case. The correlation coefficients between the true visceral fat volume and the automatically calculated visceral fat volume were over 0.999. The newly developed software is feasible for calculating visceral fat volumes in a reasonable time and was proved to have high accuracy.

Modeling the target dose fall-off in IMRT and VMAT planning techniques for cervical SBRT.

PubMed

Brito Delgado, A; Cohen, D; Eng, T Y; Stanley, D N; Shi, Z; Charlton, M; Gutiérrez, A N

2018-01-01

There has been growing interest in the use of stereotactic body radiotherapy (SBRT) technique for the treatment of cervical cancer. The purpose of this study was to characterize dose distributions as well as model the target dose fall-off for intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) delivery techniques using 6 and 10 MV photon beam energies. Fifteen (n = 15) patients with non-bulky cervical tumors were planned in Pinnacle 3 with a Varian Novalis Tx (HD120 MLC) using 6 and 10 MV photons with the following techniques: (1) IMRT with 10 non-coplanar beams (2) dual, coplanar 358° VMAT arcs (4° spacing), and (3) triple, non-coplanar VMAT arcs. Treatment volumes and dose prescriptions were segmented according to University of Texas Southwestern (UTSW) Phase II study. All plans were normalized such that 98% of the planning target volume (PTV) received 28 Gy (4 fractions). For the PTV, the following metrics were evaluated: homogeneity index, conformity index, D 2cc , D mean , D max , and dose fall-off parameters. For the organs at risk (OARs), D 2cc , D 15cc , D 0.01cc , V 20 , V 40 , V 50 , V 60 , and V 80 were evaluated for the bladder, bowel, femoral heads, rectum, and sigmoid. Statistical differences were evaluated using a Friedman test with a significance level of 0.05. To model dose fall-off, expanding 2-mm-thick concentric rings were created around the PTV, and doses were recorded. Statistically significant differences (p < 0.05) were noted in the dose fall-off when using 10 MV and VMAT 3-arc , as compared with IMRT. VMAT 3-arc improved the bladder V 40 , V 50 , and V 60 , and the bowel V 20 and V 50 . All fitted regressions had an R 2  ≥ 0.98. For cervical SBRT plans, a VMAT 3-arc approach offers a steeper dose fall-off outside of the target volume. Faster dose fall-off was observed in smaller targets as opposed to medium and large targets, denoting that OAR sparing is dependent on target size. These

Manipulating biological agents and cells in micro-scale volumes for applications in medicine

PubMed Central

Tasoglu, Savas; Gurkan, Umut Atakan; Wang, ShuQi

2013-01-01

Recent technological advances provide new tools to manipulate cells and biological agents in micro/nano-liter volumes. With precise control over small volumes, the cell microenvironment and other biological agents can be bioengineered; interactions between cells and external stimuli can be monitored; and the fundamental mechanisms such as cancer metastasis and stem cell differentiation can be elucidated. Technological advances based on the principles of electrical, magnetic, chemical, optical, acoustic, and mechanical forces lead to novel applications in point-of-care diagnostics, regenerative medicine, in vitro drug testing, cryopreservation, and cell isolation/purification. In this review, we first focus on the underlying mechanisms of emerging examples for cell manipulation in small volumes targeting applications such as tissue engineering. Then, we illustrate how these mechanisms impact the aforementioned biomedical applications, discuss the associated challenges, and provide perspectives for further development. PMID:23575660

Preconcentrator with high volume chiller for high vapor pressure particle detection

DOEpatents

Linker, Kevin L

2013-10-22

Apparatus and method for collecting particles of both high and low vapor pressure target materials entrained in a large volume sample gas stream. Large volume active cooling provides a cold air supply which is mixed with the sample gas stream to reduce the vapor pressure of the particles. In embodiments, a chiller cools air from ambient conditions to 0-15.degree. C. with the volumetric flow rate of the cold air supply being at least equal to the volumetric flow rate of the sample gas stream. In further embodiments an adsorption media is heated in at least two stages, a first of which is below a threshold temperature at which decomposition products of the high vapor pressure particle are generated.

Feasibility study of stereotactic body radiotherapy for peripheral lung tumors with a maximum dose of 100 Gy in five fractions and a heterogeneous dose distribution in the planning target volume.

PubMed

Takeda, Atsuya; Oku, Yohei; Sanuki, Naoko; Eriguchi, Takahisa; Aoki, Yousuke; Enomoto, Tatsuji; Kaneko, Takeshi; Nishimura, Shuichi; Kunieda, Etsuo

2014-09-01

We evaluated toxicity and outcomes for patients with peripheral lung tumors treated with stereotactic body radiation therapy (SBRT) in a dose-escalation and dose-convergence study. A total of 15 patients were enrolled. SBRT was performed with 60 Gy in 5 fractions (fr.) prescribed to the 60% isodose line of maximum dose, which was 100 Gy in 5 fr., covering the planning target volume (PTV) surface (60 Gy/5 fr. - (60%-isodose)) using dynamic conformal multiple arc therapy (DCMAT). The primary endpoint was radiation pneumonitis (RP) ≥ Grade 2 within 6 months. Toxicities were graded according to the Common Terminology Criteria for Adverse Events, version 4.0. Using dose-volumetric analysis, the trial regimen of 60 Gy/5 fr. - (60%-isodose) was compared with our institutional conventional regimen of 50 Gy/5 fr. - (80%-isodose). The enrolled consecutive patients had either a solitary peripheral tumor or two ipsilateral tumors. The median follow-up duration was 22.0 (12.0-27.0) months. After 6 months post-SBRT, the respective number of RP Grade 0, 1 and 2 cases was 5, 9 and 1. In the Grade 2 RP patient, the image showed an organizing pneumonia pattern at 6.0 months post-SBRT. No other toxicity was found. At last follow-up, there was no evidence of recurrence of the treated tumors. The target volumes of 60 Gy/ 5 fr. - (60%-isodose) were irradiated with a significantly higher dose than those of 50 Gy/5 fr. - (80%-isodose), while the former dosimetric parameters of normal lung were almost equivalent to the latter. SBRT with 60 Gy/5 fr. - (60%-isodose) using DCMAT allowed the delivery of very high and convergent doses to peripheral lung tumors with feasibility in the acute and subacute phases. Further follow-up is required to assess for late toxicity. © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Targets of perioperative fluid therapy and their effects on postoperative outcome: a systematic review and meta-analysis.

PubMed

Berger, M M; Gradwohl-Matis, I; Brunauer, A; Ulmer, H; Dünser, M W

2015-07-01

Perioperative fluid management plays a fundamental role in maintaining organ perfusion, and is considered to affect morbidity and mortality. Targets according to which fluid therapy should be administered are poorly defined. This systematic review aimed to identify specific targets for perioperative fluid therapy. The PubMed database (January 1993-December 2013) and reference lists were searched to identify clinical trials which evaluated specific targets of perioperative fluid therapy and reported clinically relevant perioperative endpoints in adult patients. Only studies in which targeted fluid therapy was the sole intervention were included into the main data analysis. A pooled data analysis was used to compare mortality between goal-directed fluid therapy and control interventions. Thirty-six clinical studies were selected. Sixteen studies including 1224 patients specifically evaluated targeted fluid therapy and were included into the main data analysis. Three specific targets for perioperative fluid therapy were identified: a systolic or pulse pressure variation <10-12%, an increase in stroke volume <10%, and a corrected flow time of 0.35-0.4 s in combination with an increase in stroke volume <10%. Targeting any one of these goals resulted in less postoperative complications (pooled data analysis: OR 0.53; CI95, 0.34-0.83; P=0.005) and a shorter length of intensive care unit/hospital stay, but no difference in postoperative mortality (pooled data analysis: OR 0.61; CI95, 0.33-1.11; P=0.12). This systematic review identified three goals for perioperative fluid administration, targeting of which appeared to be associated with less postoperative complications and shorter intensive care unit/hospital lengths of stay. Perioperative mortality remained unaffected.

Target-oriented imaging of hydraulic fractures by applying the staining algorithm for downhole microseismic migration

NASA Astrophysics Data System (ADS)

Lin, Ye; Zhang, Haijiang; Jia, Xiaofeng

2018-03-01

For microseismic monitoring of hydraulic fracturing, microseismic migration can be used to image the fracture network with scattered microseismic waves. Compared with conventional microseismic location-based fracture characterization methods, microseismic migration can better constrain the stimulated reservoir volume regardless of the completeness of detected and located microseismic sources. However, the imaging results from microseismic migration may suffer from the contamination of other structures and thus the target fracture zones may not be illuminated properly. To solve this issue, in this study we propose a target-oriented staining algorithm for microseismic reverse-time migration. In the staining algorithm, the target area is first stained by constructing an imaginary velocity field and then a synchronized source wavefield only concerning the target structure is produced. As a result, a synchronized image from imaging with the synchronized source wavefield mainly contains the target structures. Synthetic tests based on a downhole microseismic monitoring system show that the target-oriented microseismic reverse-time migration method improves the illumination of target areas.

Dose escalation to high-risk sub-volumes based on non-invasive imaging of hypoxia and glycolytic activity in canine solid tumors: a feasibility study

PubMed Central

2013-01-01

Introduction Glycolytic activity and hypoxia are associated with poor prognosis and radiation resistance. Including both the tumor uptake of 2-deoxy-2-[18 F]-fluorodeoxyglucose (FDG) and the proposed hypoxia tracer copper(II)diacetyl-bis(N4)-methylsemithio-carbazone (Cu-ATSM) in targeted therapy planning may therefore lead to improved tumor control. In this study we analyzed the overlap between sub-volumes of FDG and hypoxia assessed by the uptake of 64Cu-ATSM in canine solid tumors, and evaluated the possibilities for dose redistribution within the gross tumor volume (GTV). Materials and methods Positron emission tomography/computed tomography (PET/CT) scans of five spontaneous canine solid tumors were included. FDG-PET/CT was obtained at day 1, 64Cu-ATSM at day 2 and 3 (3 and 24 h pi.). GTV was delineated and CT images were co-registered. Sub-volumes for 3 h and 24 h 64Cu-ATSM (Cu3 and Cu24) were defined by a threshold based method. FDG sub-volumes were delineated at 40% (FDG40) and 50% (FDG50) of SUVmax. The size of sub-volumes, intersection and biological target volume (BTV) were measured in a treatment planning software. By varying the average dose prescription to the tumor from 66 to 85 Gy, the possible dose boost (D B ) was calculated for the three scenarios that the optimal target for the boost was one, the union or the intersection of the FDG and 64Cu-ATSM sub-volumes. Results The potential boost volumes represented a fairly large fraction of the total GTV: Cu3 49.8% (26.8-72.5%), Cu24 28.1% (2.4-54.3%), FDG40 45.2% (10.1-75.2%), and FDG50 32.5% (2.6-68.1%). A BTV including the union (∪) of Cu3 and FDG would involve boosting to a larger fraction of the GTV, in the case of Cu3∪FDG40 63.5% (51.8-83.8) and Cu3∪FDG50 48.1% (43.7-80.8). The union allowed only a very limited D B whereas the intersection allowed a substantial dose escalation. Conclusions FDG and 64Cu-ATSM sub-volumes were only partly overlapping, suggesting that the tracers offer

Communications Strategies on Alcohol and Highway Safety. Volume II. High School Youth. Final Report.

ERIC Educational Resources Information Center

Grey Advertising, Inc., New York, NY.

The second part of a two-part, two volume study deals with high school youth and identifies target populations and communications strategies for encouraging personal action steps to prevent drunk driving. Data, collected from interviews and questionnaires, are summarized and presented in tabular form. One fourth of high schoolers in a…

A numerically optimized active shield for improved TMS targeting

PubMed Central

Hernandez-Garcia, Luis; Hall, Timothy; Gomez, Luis; Michielssen, Eric

2010-01-01

Transcranial magnetic stimulation (TMS) devices suffer of poor targeting and penetration depth. A new approach to designing TMS coils is introduced in order to improve the focus of the stimulation region through the use of actively shielded probes. Iterative optimization techniques were used to design different active shielding coils for TMS probes. The new approach aims to increase the amount of energy deposited in a thin cylindrical region below the probe relative to the energy deposited elsewhere in the region (“sharpness”), while simultaneously increase the induced electric field deep in the target region relative to the surface (“penetration”). After convergence, the resulting designs showed that there is a clear tradeoff between sharpness and penetration that can be controlled by the choice of a tuning parameter. The resulting designs were tested on a realistic human head conductivity model, taking the contribution from surface charges into account. The design of choice reduced penetration depths by 16.7%. The activated surface area was reduced by 24.1 % and the volume of the activation was reduced from 42.6% by the shield. Restoring the lost penetration could be achieved by increasing the total power to the coil by 16.3%, but in that case, the stimulated volume reduction was only 13.1% and there was a slight increase in the stimulated surface area (2.9 %) PMID:20965451

3D prostate MR-TRUS non-rigid registration using dual optimization with volume-preserving constraint

NASA Astrophysics Data System (ADS)

Qiu, Wu; Yuan, Jing; Fenster, Aaron

2016-03-01

We introduce an efficient and novel convex optimization-based approach to the challenging non-rigid registration of 3D prostate magnetic resonance (MR) and transrectal ultrasound (TRUS) images, which incorporates a new volume preserving constraint to essentially improve the accuracy of targeting suspicious regions during the 3D TRUS guided prostate biopsy. Especially, we propose a fast sequential convex optimization scheme to efficiently minimize the employed highly nonlinear image fidelity function using the robust multi-channel modality independent neighborhood descriptor (MIND) across the two modalities of MR and TRUS. The registration accuracy was evaluated using 10 patient images by calculating the target registration error (TRE) using manually identified corresponding intrinsic fiducials in the whole prostate gland. We also compared the MR and TRUS manually segmented prostate surfaces in the registered images in terms of the Dice similarity coefficient (DSC), mean absolute surface distance (MAD), and maximum absolute surface distance (MAXD). Experimental results showed that the proposed method with the introduced volume-preserving prior significantly improves the registration accuracy comparing to the method without the volume-preserving constraint, by yielding an overall mean TRE of 2:0+/-0:7 mm, and an average DSC of 86:5+/-3:5%, MAD of 1:4+/-0:6 mm and MAXD of 6:5+/-3:5 mm.

Defining the optimal method for reporting prostate cancer grade and tumor extent on magnetic resonance/ultrasound fusion-targeted biopsies.

PubMed

Gordetsky, Jennifer B; Schultz, Luciana; Porter, Kristin K; Nix, Jeffrey W; Thomas, John V; Del Carmen Rodriguez Pena, Maria; Rais-Bahrami, Soroush

2018-06-01

Magnetic resonance (MR)/ultrasound fusion-targeted biopsy (TB) routinely samples multiple cores from each MR lesion of interest. Pathologists can evaluate the extent of cancer involvement and grade using an individual core (IC) or aggregate (AG) method, which could potentially lead to differences in reporting. We reviewed patients who underwent TB followed by radical prostatectomy (RP). TB cores were evaluated for grade and tumor extent by 2 methods. In the IC method, the grade for each TB lesion was based on the core with the highest Gleason score. Tumor extent for each TB was based on the core with the highest percent of tumor involvement. In the AG method, the tumor from all cores within each TB lesion was aggregated to determine the final composite grade and percentage of tumor involvement. Each method was compared with MR lesional volume, MR lesional density (lesion volume/prostate volume), and RP. Fifty-five patients underwent TB followed by RP. Extent of tumor by the AG method showed a better correlation with target lesion volume (r= 0.27,P= .022) and lesional density (r = 0.32, P = .008) than did the IC method (r= 0.19 [P = .103] andr= 0.22 [P = .062]), respectively. Extent of tumor on TB was associated with extraprostatic extension on RP by the AG method (P= .04), but not by the IC method. This association was significantly higher in patients with a grade group (GG) of 3 or higher (P= .03). A change in cancer grade occurred in 3 patients when comparing methods (2 downgraded GG3 to GG2, 1 downgraded GG4 to GG3 by the AG method). For multiple cores obtained via TB, the AG method better correlates with target lesion volume, lesional density, and extraprostatic extension. Copyright © 2018 Elsevier Inc. All rights reserved.

High-power liquid-lithium jet target for neutron production

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

Halfon, S.; Feinberg, G.; Racah Institute of Physics, Hebrew University, Jerusalem 91904

2013-12-15

A compact liquid-lithium target (LiLiT) was built and tested with a high-power electron gun at the Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the {sup 7}Li(p,n){sup 7}Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy. The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm{sup 3}) with fast transport. The target was designed based onmore » a thermal model, accompanied by a detailed calculation of the {sup 7}Li(p,n) neutron yield, energy distribution, and angular distribution. Liquid lithium is circulated through the target loop at ∼200 °C and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power areal densities of >4 kW/cm{sup 2} and volume power density of ∼2 MW/cm{sup 3} at a lithium flow of ∼4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91–2.5 MeV, 1–2 mA) at SARAF.« less

The area-time-integral technique to estimate convective rain volumes over areas applied to satellite data - A preliminary investigation

NASA Technical Reports Server (NTRS)

Doneaud, Andre A.; Miller, James R., Jr.; Johnson, L. Ronald; Vonder Haar, Thomas H.; Laybe, Patrick

1987-01-01

The use of the area-time-integral (ATI) technique, based only on satellite data, to estimate convective rain volume over a moving target is examined. The technique is based on the correlation between the radar echo area coverage integrated over the lifetime of the storm and the radar estimated rain volume. The processing of the GOES and radar data collected in 1981 is described. The radar and satellite parameters for six convective clusters from storm events occurring on June 12 and July 2, 1981 are analyzed and compared in terms of time steps and cluster lifetimes. Rain volume is calculated by first using the regression analysis to generate the regression equation used to obtain the ATI; the ATI versus rain volume relation is then employed to compute rain volume. The data reveal that the ATI technique using satellite data is applicable to the calculation of rain volume.