{"id":{"repo_id":"ohiolink","oai_identifier":"oai:etd.ohiolink.edu:mco1364343813"},"canonical_url":"https://search.dev.ndltd.org/etd/ohiolink/oai:etd.ohiolink.edu:mco1364343813","repository":{"repo_id":"ohiolink","name":"OhioLINK","base_url":"https://etd.ohiolink.edu/acprod/odb_etd/ws/oai/oai"},"display":{"title":"Development of a Comprehensive Linac-based Quality Assurance Program for a Retrofitted Micro-MLC SRS System","abstract":"In Stereotactic Radiosurgery, one of the most import factors that must be measured is the accuracy of the localization system, whether it be lasers or camera system; and the coincidence of the localized isocenter to the radiation isocenter. According to TG-142 the minimum deviation between the isocenter determined by the localization device and the radiation isocenter of the machine must be no more that 1 mm. In addition, the minimum deviation, also recommended by TG-142, between the radiation isocenter and the mechanical isocenter of the machine must be no more that 1mm.The purpose of this research was to develop a method that both of these parameters could be measured and add these tests to our patient specific QA, monthly QA, and annual QA procedures. A plastic phantom was constructed with holes drilled in each of the sides to meet at a common point in the middle of the phantom. This common intersection was then set as the isocenter for the treatment beams, and the coordinates of the point were sent to the camera system. Measurements were than taken with both the EPID and GafChromic film with the use of rigid tungsten rods in each hole to mark the position of the holes on the film and EPID. The films were then scanned and the field edges and isocenter positions were determined by taking the coordinates of a point that was halfway between the minimum and maximum points in all cases.","abstract_html":"In Stereotactic Radiosurgery, one of the most import factors that must be measured is the accuracy of the localization system, whether it be lasers or camera system; and the coincidence of the localized isocenter to the radiation isocenter. According to TG-142 the minimum deviation between the isocenter determined by the localization device and the radiation isocenter of the machine must be no more that 1 mm. In addition, the minimum deviation, also recommended by TG-142, between the radiation isocenter and the mechanical isocenter of the machine must be no more that 1mm.The purpose of this research was to develop a method that both of these parameters could be measured and add these tests to our patient specific QA, monthly QA, and annual QA procedures. A plastic phantom was constructed with holes drilled in each of the sides to meet at a common point in the middle of the phantom. This common intersection was then set as the isocenter for the treatment beams, and the coordinates of the point were sent to the camera system. Measurements were than taken with both the EPID and GafChromic film with the use of rigid tungsten rods in each hole to mark the position of the holes on the film and EPID. The films were then scanned and the field edges and isocenter positions were determined by taking the coordinates of a point that was halfway between the minimum and maximum points in all cases.","abstract_has_math":false,"creators":["Hancock, George H."],"institution":"University of Toledo Health Science Campus","degree_name":"Master of Science in Biomedical Sciences (MSBS)","degree_level":"masters","degree_discipline":"College of Medicine","degree_department":null,"school":null,"contributors":["Pearson, David"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-05-20","date_published":"2013-05-20","updated_at":"2026-07-24T03:37:01Z","subjects":["Physics","Radiation"],"languages":["English"],"rights":["unrestricted","This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. 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In addition, the minimum deviation, also recommended by TG-142, between the radiation isocenter and the mechanical isocenter of the machine must be no more that 1mm.The purpose of this research was to develop a method that both of these parameters could be measured and add these tests to our patient specific QA, monthly QA, and annual QA procedures. A plastic phantom was constructed with holes drilled in each of the sides to meet at a common point in the middle of the phantom. This common intersection was then set as the isocenter for the treatment beams, and the coordinates of the point were sent to the camera system. Measurements were than taken with both the EPID and GafChromic film with the use of rigid tungsten rods in each hole to mark the position of the holes on the film and EPID. The films were then scanned and the field edges and isocenter positions were determined by taking the coordinates of a point that was halfway between the minimum and maximum points in all cases."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf","p.60","5.02 MB"]},{"key":"dc:title","label":"Title","values":["Development of a Comprehensive Linac-based Quality Assurance Program for a Retrofitted Micro-MLC SRS System"]}]}],"canonical_facts":{"dc:contributor":["Pearson, David"],"dc:creator":["Hancock, George H."],"dc:date":["2013-05-20"],"dc:description":["In Stereotactic Radiosurgery, one of the most import factors that must be measured is the accuracy of the localization system, whether it be lasers or camera system; and the coincidence of the localized isocenter to the radiation isocenter. According to TG-142 the minimum deviation between the isocenter determined by the localization device and the radiation isocenter of the machine must be no more that 1 mm. In addition, the minimum deviation, also recommended by TG-142, between the radiation isocenter and the mechanical isocenter of the machine must be no more that 1mm.The purpose of this research was to develop a method that both of these parameters could be measured and add these tests to our patient specific QA, monthly QA, and annual QA procedures. A plastic phantom was constructed with holes drilled in each of the sides to meet at a common point in the middle of the phantom. This common intersection was then set as the isocenter for the treatment beams, and the coordinates of the point were sent to the camera system. Measurements were than taken with both the EPID and GafChromic film with the use of rigid tungsten rods in each hole to mark the position of the holes on the film and EPID. The films were then scanned and the field edges and isocenter positions were determined by taking the coordinates of a point that was halfway between the minimum and maximum points in all cases."],"dc:format":["application/pdf","p.60","5.02 MB"],"dc:identifier":["http://rave.ohiolink.edu/etdc/view?acc_num=mco1364343813"],"dc:language":["English"],"dc:publisher":["University of Toledo Health Science Campus / OhioLINK"],"dc:rights":["unrestricted","This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. Specific terms and permissions are available from this document's record in the OhioLINK ETD Center."],"dc:subject":["Physics","Radiation"],"dc:title":["Development of a Comprehensive Linac-based Quality Assurance Program for a Retrofitted Micro-MLC SRS System"],"dc:type":["Electronic Thesis or Dissertation"],"thesis:degree_discipline":["College of Medicine"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science in Biomedical Sciences (MSBS)"],"thesis:institution_name":["University of Toledo Health Science Campus"]},"updated_at":"2026-07-24T03:37:01Z"}