Deformable Dose Accumulation with Image Guided Radiotherapy for Final Dose Evaluation in Pelvic Cases

Abstract

This study aims at a method that employs deformable dose accumulation for the evaluation of the results of intensity-modulated radiation therapy (IMRT) in pelvic cases. Each fraction dose was derived from the planning dose through rigid transformation accounting for setup corrections. Daily cone-beam CT (CBCT) images were used to deform the daily fraction dose to a reference geometry, which in our study was the first fraction geometry. A commercial software system, MIMvista, was used to perform deformable image registration, dose deformation, and dose accumulation. The differences in distributions of accumulated dose and planned dose were observed. The application of deformable dose accumulation is particularly useful in final accumulated dose evaluation throughout radiotherapy treatment, especially for the cases where there are significant deformations of planning target volume (PTV) and organs at risk (OARs).