Verification of Radiation Fluence using Stack Film in HDR Brachytherapy with Heterogeneity Algorithm XC05-XC10
Dr. Mourougan Sinnatamby,
Assistant Professor, Department of Radiation Oncology, Regional Cancer Centre, JIPMER, Puducherry, India.
Introduction: It is essential that Quality Assurance (QA) need to be in line with progresses in HDR brachytherapy treatment planning and delivery to ensure an appropriate level of dosimetric accuracy and quality.
Aim: To verify radiation fluence using stack films in HDR brachytherapy with heterogeneity algorithm.
Materials and Methods: Gafchromic EBT2 films were stacked in different experimental setup and each film acted as dosimeter to validate AcurosTMBV algorithm in HDR brachytherapy. These films were read using Epson expression 10000 XL flatbed scanner, calibrated against the standard value and analysed with Film QA Pro 2015 software. Different criterion were set for gamma analysis which include Dose Difference (DD)/Distance-To-Agreement (DTA); 2%/1 mm, 5%/1 mm, 10%/1 mm.
Results: In order to validate the point doses calculated using model based dose calculation algorithm (AcurosTM BV), a virtual phantom created in the TPS, which agreed with MC based calculation mostly within 2%. The results of each plane were analysed in all the experimental setup. In the gamma pass criteria of 2% and 1 mm, 92% passed, in 5% and 1 mm criteria 96% passed and with 10% and 1 mm criteria, almost 100% passing rate was achieved.
Conclusion: Methods provide a comprehensive verification for commissioning the MBDCA-AcurosTM BV and are recommended to use stack film for QA program in HDR brachytherapy.