{"id":{"repo_id":"buffalo","oai_identifier":"oai:ubir.buffalo.edu:10477/86719"},"canonical_url":"https://search.dev.ndltd.org/etd/buffalo/oai:ubir.buffalo.edu:10477/86719","repository":{"repo_id":"buffalo","name":"Buffalo","base_url":"https://ubir.buffalo.edu/oai/request"},"display":{"title":"VMAT Collimator Angle Optimization","abstract":"Ph.D.","abstract_html":"Ph.D.","abstract_has_math":false,"creators":["Kilian-Meneghin, Joshua"],"institution":"State University of New York at Buffalo","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Kumaraswamy, Lalith","Radiology"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-02-21T21:36:49Z","date_published":"2025-02-21T21:36:49Z","updated_at":"2026-07-27T19:05:34Z","subjects":["nuclear physics and radiation"],"languages":["eng"],"rights":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10477/86719","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Kumaraswamy, Lalith","Radiology"]},{"key":"dc:creator","label":"Author","values":["Kilian-Meneghin, Joshua"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-02-21T21:36:49Z","2020"]},{"key":"dc:publisher","label":"Institution","values":["State University of New York at Buffalo"]},{"key":"dc:type","label":"Dc Type","values":["Text","Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["nuclear physics and radiation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/10477/86719"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Ph.D.","Purpose: To quantify the benefits of collimator angle optimization and implement a clinically feasible method to utilize those benefits. Methods: A dosimetric study was planned with first the geometric shapes from TG 119 followed by a patient sample. The final patient sample included five GBM and five esophageal patients. A Matlab algorithm and application was developed to simulate conformal fitting of the MLC to the target structure, which was extracted from the patient CT using CERR. From this fit, a conformally optimal collimator angle can be determined for each VMAT control point. Eclipse was used as the treatment planning system and results were validated with professional dosimetrist plans. Results: Generating an optimized collimator angle solution within Eclipse is too time consuming to be clinically applicable (8 hours). Equivalent results with a calculation time on the order of half an hour are possible with the in-house conformal collimator angle optimization application. 5/6 patients evaluated with the Roswell score saw an averaged relative improvement of 8% as compared to the standard clinical plan while other patients received no benefit. Geometric analysis would indicate that the individual anatomic differences likely account for the observed discrepancy. Conclusion: Collimator angle optimization is feasible with current equipment. OAR dose reductions are possible in half the tested population. An application to assist dosimetrists in planning with collimator angles optimized for the specific patient was developed to utilize these results. Fully dynamic collimator rotation is not yet clinically feasible with Varian systems but shows promise.","**To request an accessible version of the file(s) associated with this item, contact library@buffalo.edu. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.**"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["VMAT Collimator Angle Optimization"]}]}],"canonical_facts":{"dc:contributor":["Kumaraswamy, Lalith","Radiology"],"dc:creator":["Kilian-Meneghin, Joshua"],"dc:date":["2025-02-21T21:36:49Z","2020"],"dc:description":["Ph.D.","Purpose: To quantify the benefits of collimator angle optimization and implement a clinically feasible method to utilize those benefits. Methods: A dosimetric study was planned with first the geometric shapes from TG 119 followed by a patient sample. The final patient sample included five GBM and five esophageal patients. A Matlab algorithm and application was developed to simulate conformal fitting of the MLC to the target structure, which was extracted from the patient CT using CERR. From this fit, a conformally optimal collimator angle can be determined for each VMAT control point. Eclipse was used as the treatment planning system and results were validated with professional dosimetrist plans. Results: Generating an optimized collimator angle solution within Eclipse is too time consuming to be clinically applicable (8 hours). Equivalent results with a calculation time on the order of half an hour are possible with the in-house conformal collimator angle optimization application. 5/6 patients evaluated with the Roswell score saw an averaged relative improvement of 8% as compared to the standard clinical plan while other patients received no benefit. Geometric analysis would indicate that the individual anatomic differences likely account for the observed discrepancy. Conclusion: Collimator angle optimization is feasible with current equipment. OAR dose reductions are possible in half the tested population. An application to assist dosimetrists in planning with collimator angles optimized for the specific patient was developed to utilize these results. Fully dynamic collimator rotation is not yet clinically feasible with Varian systems but shows promise.","**To request an accessible version of the file(s) associated with this item, contact library@buffalo.edu. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.**"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/10477/86719"],"dc:language":["eng"],"dc:publisher":["State University of New York at Buffalo"],"dc:rights":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."],"dc:subject":["nuclear physics and radiation"],"dc:title":["VMAT Collimator Angle Optimization"],"dc:type":["Text","Dissertation"]},"updated_at":"2026-07-27T19:05:34Z"}