Medicine and Health Sciences Commons^™

Modeling Of Island Block Scatter For Intensity Modulated Bolus Electron Conformal Therapy, Joseph G. Scotto

LSU Master's Theses

Purpose: Bolus electron conformal therapy (BECT) benefits treatment of the post-mastectomy chest wall, head and neck, paraspinal muscles, and extremities. Patient dose heterogeneities caused by bolus can be reduced through intensity modulation (IM) across the incident electron beam. This requires passive radiotherapy intensity modulation for electrons (PRIME) devices, which utilize tungsten pins (island blocks) imbedded in machinable foam. IM-BECT treatment planning requires accurate dose calculation using the pencil beam redefinition dose algorithm (PBRA). Currently, the PBRA models island blocks as perfect collimators. This work explores models to account for electrons scattering into and out of the sides of island blocks. …

Comparative Effectiveness Of Intensity Modulated Radiation Therapy To 3-Dimensional Conformal Radiation In Locally Advanced Lung Cancer: Pathological And Clinical Outcomes., Sarit Appel, Jair Bar, Alon Ben-Nun, Marina Perelman, Dror Alezra, Damien Urban, Maoz Ben-Ayun, Nir Honig, Efrat Ofek, Tamar Katzman, Amir Onn, Sumit Chatterji, Sergey Dubinski, Lev Tsvang, Shira Felder, Judith Kraitman, Ory Haisraely, Tatiana Rabin Alezra, Sivan Lieberman, Edith M. Marom, Nir Golan, David Simansky, Zvi Symon, Yaacov Richard Lawrence

Department of Radiation Oncology Faculty Papers

OBJECTIVE: Intensity-modulated radiotherapy (IMRT) has better normal-tissue sparing compared with 3-dimensional conformal radiation (3DCRT). We sought to assess the impact of radiation technique on pathological and clinical outcomes in locally advanced non-small cell lung cancer (LANSCLC) treated with a trimodality strategy.

METHODS: Retrospective review of LANSCLC patients treated from August 2012 to August 2018 at Sheba Medical Center, Israel. The trimodality strategy consisted of concomitant chemoradiation to 60 Gray (Gy) followed by completion surgery. The planning target volume (PTV) was defined by co-registered PET/CT. Here we compare the pathological regression, surgical margin status, local control rates (LC), disease free (DFS) …

Nrg Oncology-Radiation Therapy Oncology Group Study 1014: 1-Year Toxicity Report From A Phase 2 Study Of Repeat Breast-Preserving Surgery And 3-Dimensional Conformal Partial-Breast Reirradiation For In-Breast Recurrence., Douglas W. Arthur, Kathryn A. Winter, Henry M. Kuerer, Bruce G. Haffty, Laurie W. Cuttino, Dorin A. Todor, Nicole L. Simone, Shelly B. Hayes, Wendy A. Woodward, Beryl Mccormick, Randi J. Cohen, Walter M. Sahijdak, Daniel J. Canaday, Doris R. Brown, Adam D. Currey, Christine M. Fisher, Reshma Jagsi, Julia White

Department of Radiation Oncology Faculty Papers

PURPOSE: To determine the associated toxicity, tolerance, and safety of partial-breast reirradiation.

METHODS AND MATERIALS: Eligibility criteria included in-breast recurrence occurring >1 year after whole-breast irradiation, <3 >cm, unifocal, and resected with negative margins. Partial-breast reirradiation was targeted to the surgical cavity plus 1.5 cm; a prescription dose of 45 Gy in 1.5 Gy twice daily for 30 treatments was used. The primary objective was to evaluate the rate of grade ≥3 treatment-related skin, fibrosis, and/or breast pain adverse events (AEs), occurring ≤1 year from re-treatment completion. A rate of ≥13% for these AEs in a cohort of 55 patients was …

Adjuvant Radiation Therapy, Androgen Deprivation, And Docetaxel For High-Risk Prostate Cancer Postprostatectomy: Results Of Nrg Oncology/Rtog Study 0621., Mark D. Hurwitz, Jonathan Harris, Oliver Sartor, Ying Xiao, Bobby Shayegan, Paul W. Sperduto, Kasra R. Badiozamani, Colleen A.F. Lawton, Eric M. Horwitz, Jeff M. Michalski, Kevin Roof, David C. Beyer, Qiang Zhang, Howard M. Sandler

Department of Radiation Oncology Faculty Papers

BACKGROUND: Phase 3 trials have demonstrated a benefit from adjuvant radiation therapy (ART) for men who have adverse factors at radical prostatectomy (RP). However, some patients have a high risk of progression despite ART. The role of systemic therapy with ART in this high-risk group remains to be defined.

METHODS: Patients who had either a post-RP prostate-specific antigen (PSA) nadir > 0.2 ng/mL and a Gleason score ≥7 or a PSA nadir ≤0.2 ng/mL, a Gleason score ≥8, and a pathologic tumor (pT) classification ≥ pT3 received 6 months of androgen-deprivation therapy (ADT) plus radiotherapy and 6 cycles of docetaxel. The …

Flattening Filter-Free Accelerators: A Report From The Aapm Therapy Emerging Technology Assessment Work Group., Ying Xiao, Stephen F Kry, Richard Popple, Ellen Yorke, Niko Papanikolaou, Sotirios Stathakis, Ping Xia, Saiful Huq, John Bayouth, James Galvin Phd, Fang-Fang Yin

Department of Medicine Faculty Papers

This report describes the current state of flattening filter-free (FFF) radiotherapy beams implemented on conventional linear accelerators, and is aimed primarily at practicing medical physicists. The Therapy Emerging Technology Assessment Work Group of the American Association of Physicists in Medicine (AAPM) formed a writing group to assess FFF technology. The published literature on FFF technology was reviewed, along with technical specifications provided by vendors. Based on this information, supplemented by the clinical experience of the group members, consensus guidelines and recommendations for implementation of FFF technology were developed. Areas in need of further investigation were identified. Removing the flattening filter …

Prediction Of Radiation Pneumonitis By Dose-Volume Histogram Parameters In Lung Cancer--A Systematic Review, George Rodrigues, Michael Lock, David D'Souza, Edward Yu, Jake Van Dyk

Michael Lock

BACKGROUND AND PURPOSE: To perform a systematic review of the predictive ability of various dose-volume histogram (DVH) parameters (V(dose), mean lung dose (MLD), and normal tissue complication probability (NTCP)) in the incidence of radiation pneumonitis (RP) caused by external-beam radiation therapy.

METHODS AND MATERIALS: Studies assessing the relationship between CT-based DVH reduction parameters and RP rate in radically treated lung cancer were eligible for the review. Synonyms for RP, lung cancer, DVH and its associated parameters (NTCP, V(20), V(30), MLD) were combined in a search strategy involving electronic databases, secondary reference searching, and consultation with experts. Individual or group data …

Dosimetric Evaluation Of Heterogeneity Corrections For Rtog 0236: Stereotactic Body Radiotherapy Of Inoperable Stage I-Ii Non-Small-Cell Lung Cancer., Ying Xiao, Lech Papiez, Rebecca Paulus, Robert Timmerman, William L. Straube, Walter R. Bosch, Jeff Michalski, James M. Galvin

Department of Radiation Oncology Faculty Papers

PURPOSE: Using a retrospective analysis of treatment plans submitted from multiple institutions accruing patients to the Radiation Therapy Oncology Group (RTOG) 0236 non-small-cell stereotactic body radiotherapy protocol, the present study determined the dose prescription and critical structure constraints for future stereotactic body radiotherapy lung protocols that mandate density-corrected dose calculations.

METHOD AND MATERIALS: A subset of 20 patients from four institutions participating in the RTOG 0236 protocol and using superposition/convolution algorithms were compared. The RTOG 0236 protocol required a prescription dose of 60 Gy delivered in three fractions to cover 95% of the planning target volume. Additional requirements were specified …

Adaptive Radiation Therapy For Localized Mesothelioma With Mediastinal Metastasis Using Helical Tomotherapy., James Renaud, Slav Yartsev, A Rashid Dar, Jacob Van Dyk

Oncology Publications

The purpose of this study was to compare 2 adaptive radiotherapy strategies with helical tomotherapy. A patient having mesothelioma with mediastinal nodes was treated using helical tomotherapy with pretreatment megavoltage CT (MVCT) imaging. Gross tumor volumes (GTVs) were outlined on every MVCT study. Two alternatives for adapting the treatment were investigated: (1) keeping the prescribed dose to the targets while reducing the dose to the OARs and (2) escalating the target dose while maintaining the original level of healthy tissue sparing. Intensity modulated radiotherapy (step-and-shoot IMRT) and 3D conformal radiotherapy (3DCRT) plans for the patient were generated and compared. The …

Comparative Planning Evaluation Of Intensity-Modulated Radiotherapy Techniques For Complex Lung Cancer Cases, Slav Yartsev, Jeff Chen, Edward Yu, Tomas Kron, George Rodrigues, Terry Coad, Kristina Trenka, Eugene Wong, Glenn Bauman, Jake Van Dyk

Edward Yu

Background and purpose: Lung cancer treatment can be one of the most challenging fields in radiotherapy. The aim of the present study was to compare different modalities of radiation delivery based on a balanced scoring scheme for target coverage and normal tissue avoidance. Patients and methods: Treatment plans were developed for 15 patients with stage III inoperable non-small cell lung cancer using 3D conformal technique and intensity-modulated radiotherapy (IMRT). Elective nodal irradiation was included for all cases to create the most challenging scenarios with large target volumes. A 2 cm margin was used around the gross tumour volume (GTV) to …

Planning Evaluation Of Radiotherapy For Complex Lung Cancer Cases Using Helical Tomotherapy, Tomas Kron, Grigor Grigorov, Edward Yu, Slav Yartsev, Jeff Chen, Eugene Wong, George Rodrigues, Kris Trenka, Terry Coad, Glenn Bauman, Jake Van Dyk

Edward Yu

Lung cancer treatment is one of the most challenging fields in radiotherapy. The aim of the present study was to investigate what role helical tomotherapy (HT), a novel approach to the delivery of highly conformal dose distributions using intensity-modulated radiation fan beams, can play in difficult cases with large target volumes typical for many of these patients. Tomotherapy plans were developed for 15 patients with stage III inoperable non-small-cell lung cancer. While not necessarily clinically indicated, elective nodal irradiation was included for all cases to create the most challenging scenarios with large target volumes. A 2 cm margin was used …

Prediction Of Radiation Pneumonitis By Dose-Volume Histogram Parameters In Lung Cancer--A Systematic Review, George Rodrigues, Michael Lock, David D'Souza, Edward Yu, Jake Van Dyk

Edward Yu

BACKGROUND AND PURPOSE: To perform a systematic review of the predictive ability of various dose-volume histogram (DVH) parameters (V(dose), mean lung dose (MLD), and normal tissue complication probability (NTCP)) in the incidence of radiation pneumonitis (RP) caused by external-beam radiation therapy. METHODS AND MATERIALS: Studies assessing the relationship between CT-based DVH reduction parameters and RP rate in radically treated lung cancer were eligible for the review. Synonyms for RP, lung cancer, DVH and its associated parameters (NTCP, V(20), V(30), MLD) were combined in a search strategy involving electronic databases, secondary reference searching, and consultation with experts. Individual or group data …

Radiation Treatment Of Lung Cancer--Patterns Of Practice In Canada, Patricia Tai, Edward Yu, Jerry Battista, Jake Van Dyk

Edward Yu

BACKGROUND AND PURPOSE: To assess the patterns of practice among Canadian radiation oncologists who treat lung cancers. PATIENTS AND METHODS: A questionnaire detailing different aspects of radiation treatment of lung cancer was mailed to all radiation oncologists treating lung cancer in Canada. Seventy-two percent (74/103) of radiation oncologists who treat lung cancer from all 34 Canadian cancer centres replied to the questionnaire. RESULTS: (a) Radiotherapy regimens in Canadian cancer centres are in accordance with several major randomised studies. There is still some variation in treatment practice that may be due to unresolved controversies or limited resources. The most frequently used …

Improving The Consistency In Cervical Esophageal Target Volume Definition By Special Training, Patricia Tai, Jake Van Dyk, Jerry Battista, Edward Yu, Larry Stitt, Jon Tonita, Olusegun Agboola, James Brierley, Rashid Dar, Christopher Leighton, Shawn Malone, Barbara Strang, Pauline Truong, Gregory Videtic, C. Wong, Rebecca Wong, Youssef Youssef

Edward Yu

PURPOSE: 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. METHODS AND MATERIALS: 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 …

Variability Of Target Volume Delineation In Cervical Esophageal Cancer, Patricia Tai, Jake Van Dyk, Edward Yu, Jerry Battista, Larry Stitt, Terry Coad

Edward Yu

PURPOSE: Three-dimensional (3D) conformal radiation therapy (CRT) assumes and requires the precise delineation of the target volume. To assess the consistency of target volume delineation by radiation oncologists, who treat esophageal cancers, we have performed a transCanada survey. MATERIALS AND METHODS: One of three case presentations, including CT scan images, of different stages of cervical esophageal cancer was randomly chosen and sent by mail. Respondents were asked to fill in questionnaires regarding treatment techniques and to outline boost target volumes for the primary tumor on CT scans, using ICRU-50 definitions. RESULTS: Of 58 radiation oncologists who agreed to participate, 48 …