Prospective development of an individualised predictive model for treatment coverage using offline cone beam computed tomography surrogate measures in post-prostatectomy radiotherapy

Abstract

The aim of this study is to prospectively evaluate and model surrogate explanatory variables (SEVs) of target coverage and rectal dose pertaining to soft tissue anatomy visualised on cone beam computed tomography (CBCT) for incorporation into post-prostatectomy treatment coverage verification protocols. Twenty post-prostatectomy patients treated with conformal prostate bed radiotherapy (64-74 Gy) underwent CBCT daily at fractions 1 to 5, and then weekly. Treatment coverage was defined on each CBCT using 'PTV95', percentage of the CBCT PTV covered by original treatment fields, and 'RECTD50', dose delivered to 50% of CBCT rectal volume by original treatment fields. Three candidate SEVs for tre..