The Characteristics and Implementation of XR-RV3 GafchromicFilm for Radiotherapy Dosimetry

Abstract

The purpose of this study is to compare the dosimetry characterization of XR-RV3 to EBT2 gafchromic film and also to implement both films in order to verify the dose of radiotherapy on IMRT and VMAT. The film response of each energies (foton 6 MV, 10 MV and Cobalt-60) was measured over the dose levels from 50 cGy to 10 Gy. Each film piece was scanned using EPSON Perfection V700 flatbed scanner, 48-bit color, 75 dpi spatial resolution. The data were analyzed using FilmQA Pro for each images with ROI size 3 x 3 cm² . Furthermore, the evaluation of targeted dose is determined by putting films of Gafchromic XR-RV3 and EBT2 on Rando Alderson slab fantom to simulate prostate cancer. The experiment was performed with Varian Clinac Trilogy, Inc. Two cases of IMRT and VMAT plans were made using Eclipse TPS ver. 10. Exposed Gafchromic films was scanned using Epson Perfection V700 into (.TIF) format in 720dpi and RGB 48 bit was analyzed by using in-house algorithm and FilmQA pro. The comparison between EBT2 and XRRV3 Gafchromic films were used to obtain average dose in the form of histogram curve. From this study, the result revealed that there was no significant difference in characteristics response between XR-RV3 and EBT2 film with standard deviation of ±3%. The energy dependence of XR-RV3 and EBT2 film was found to be relatively small within measurement uncertainties ±1%. The dependence of XR-RV3 film side orientation is negligibly small with the standard deviation of 0.2. On the other hand, the percentage of errors in the case of verification of prostate cancer toward the planned dose were -4.85% in EBT2 Gafchromic films and - 1.94% in the XR-RV3 Gafchromic films on IMRT technique, whereas for VMAT were -4.48% on EBT2 Gafchromic films and - 7.47% on XR-RV3 Gafchromic films.