Masking Enhances Accuracy of Bladder Deformation in Multifraction Adaptive Brachytherapy as a First Step toward Composite Dose Estimation

Abstract

GEC-ESTRO guidelines for cervix HDR brachytherapy advocate measurement of the 2cc dose received by organs at risk (OAR) and its summation across multiple treatment fractions to give a worst-case-scenario total cumulative dose estimate. If the OAR from different fractions could be accurately co-registered using deformation, then a more accurate composite dose could be obtained. As a first step toward composite dose estimation, we sought to assess and improve the quality of bladder deformation using a technique called masking, which involves resetting the pixel values within a contour.