Commissioning of portal dosimetry using a novel method for flattening filter-free photon beam in a nontrue beam linear accelerator

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dc.contributor.authorGandhi, Arunen_US
dc.contributor.authorVellaiyan, Subramanien_US
dc.contributor.authorSubramanian, VSen_US
dc.contributor.authorShanmugam, Thirumalaiswamyen_US
dc.contributor.authorMurugesan, Kathirvelen_US
dc.contributor.authorSubramanian, Kalaen_US
dc.date.accessioned2020-11-18T10:07:35Z
dc.date.available2020-11-18T10:07:35Z
dc.date.issued2019-01
dc.description.abstractAim: The aim of this study is to commission and validate the portal dosimetry (PD) system using an indirect method for flattening filter free (FFF) photon beam of the upgraded c-series linear accelerator. Background: Varian Medical System clinacs with amorphous-silicon portal imager panel (aSi-1000) do not have PD for FFF beams. Recently, our c-series linear accelerator was upgraded to deliver 6MV FFF (6MVFFF) photon beam with the highest dose rate of 1400 monitor unit (MU)/min. The study, therefore, focuses on the commissioning and validation of PD for the 6MVFFF beam. Materials and Methods: An indirect method was implemented to predict the portal dose for FFF beam in Eclipse as the treatment planning system does not have direct prediction algorithm for FFF beam (version. 11). Dosimetrical characteristics of aSi-electronic portal imaging device (EPID) were evaluated for 6MVFFF beam and validation of PD for 6MVFFF beam was performed for open fields along with pretreatment quality assurance of intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT), and stereotactic radiosurgery (SRS) techniques for 30 patients planned with 6MVFFF beam. Results: ASi-EPID saturates between 100 and 130 cm source to detector distance (SDD) for 6MVFFF beam and resolved at more than 140 cm SDD. The squared correlation coefficient (R2) for MU linearity was found to be 1 (R2 = 1), and instantaneous dose response linearity at different SDD's was found to be 0.999 (R2 = 0.999) for the 6MVFFF beam. Maximum gamma area index (GAI) for 3% dose difference and 3 mm distance-to-agreement criteria for IMRT, VMAT, and SRS/stereotactic radiotherapy plans was 97.9% ± 0.3%, 96.3% ± 0.5%, and 98.2% ± 0.2%, respectively. Conclusion: The results reveal that this novel method can be used to commission portal dosimetry for 6MVFFF beam as it is a convenient, faster, and accurate methoden_US
dc.identifier.affiliationsDepartment of Radiation Oncology, Yashoda Hospitals, Hyderabad, Telangana; Research and Development Centre, Bharathiar University, Coimbatore, Tamil Nadu, Indiaen_US
dc.identifier.affiliationsResearch and Development Centre, Bharathiar University, Coimbatore, Tamil Nadu; Department of Radiotherapy, All India Institute of Medical Sciences, New Delhi, Indiaen_US
dc.identifier.affiliationsDepartment of Radiation Oncology, Yashoda Hospitals, Hyderabad, Telangana; Research and Development Centre, Bharathiar University, Coimbatore, Tamil Nadu, Indiaen_US
dc.identifier.affiliationsDepartment of Radiation Oncology, Yashoda Hospitals, Hyderabad, Telangana, Indiaen_US
dc.identifier.affiliationsDepartment of Radiation Oncology, Yashoda Hospitals, Hyderabad, Telangana; Research and Development Centre, Bharathiar University, Coimbatore, Tamil Nadu, Indiaen_US
dc.identifier.affiliationsDepartment of Radiation Oncology, Yashoda Hospitals, Hyderabad, Telangana, Indiaen_US
dc.identifier.citationGandhi Arun, Vellaiyan Subramani, Subramanian VS, Shanmugam Thirumalaiswamy, Murugesan Kathirvel, Subramanian Kala. Commissioning of portal dosimetry using a novel method for flattening filter-free photon beam in a nontrue beam linear accelerator. Journal of Cancer Research and Therapeutics. 2019 Jan; 15(1): 223-230en_US
dc.identifier.issn0973-1482
dc.identifier.placeIndiaen_US
dc.identifier.urihttps://imsear.searo.who.int/handle/123456789/213595
dc.languageenen_US
dc.publisherWolters Kluwer India Pvt. Ltd.en_US
dc.relation.issuenumber1en_US
dc.relation.volume15en_US
dc.source.urihttps://dx.doi.org//10.4103/jcrt.JCRT_1181_16en_US
dc.subjectASi-electronic portal imaging deviceen_US
dc.subjectflattening filter free beamen_US
dc.subjectportal dosimetryen_US
dc.subjectvolumetric-modulated arc therapyen_US
dc.titleCommissioning of portal dosimetry using a novel method for flattening filter-free photon beam in a nontrue beam linear acceleratoren_US
dc.typeJournal Articleen_US
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