title: Suitability of radiochromic films for dosimetry of very-low energy X-rays.
abstract: This study examined the response characteristics of three commercially available radiochromic films when exposed to low energy (50 kVp) X-rays. The aim was to evaluate the films for potential use in 2D dosimetry for a low-kV intraoperative radiotherapy (IORT) device known as the 'Intrabeam'. Dose-response relationships were obtained for Gafchromic EBT, XR-RV2, and XR-QA film in water at several distances from the Intrabeam device. It was found that the dose rates from the source were excessive for use of the XR-QA film, and that all three film types showed significant energy dependence within the limits of measurement uncertainty. Basic modeling of primary X-ray spectra indicated large changes in the lower energy components with distance from the source, and it is hypothesized that the changes in film response are a result of changes in film energy response. This is in contrast to previous studies indicating less or negligible energy response. All films showed non-linearity in response over the ranges examined. These results imply significant limitations for the use of these films for low-kV dosimetry.
authors.affiliation: Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, 6009.|School of Physics, University of Western Australia, Crawley, Western Australia, 6009.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Ebert
authors.affiliation: Department of Imaging and Applied Physics, Curtin University of Technology, Bentley, Western Australia, 6102.
authors.forename: Ali H
authors.initials: AH
authors.lastname: Asad
authors.affiliation: Department of Imaging and Applied Physics, Curtin University of Technology, Bentley, Western Australia, 6102.
authors.forename: Salim A
authors.initials: SA
authors.lastname: Siddiqui
mesh_terms: D002138:Calibration; D004307:Dose-Response Relationship, Radiation; D005373:Film Dosimetry / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D007430:Intraoperative Care; D011880:Radiotherapy Planning, Computer-Assisted; D014962:X-Ray Film