How to identify rectal sub-regions likely involved in rectal bleeding in prostate cancer radiotherapy?

摘要

Nowadays, the definition of patient-specific constraints in prostate cancer radiotherapy planning are solely based on dose-volume histogram (DVH) parameters. Nevertheless those DVH models lack of spatial accuracy since they do not use the complete 3D information of the dose distribution. The goal of the study was to propose an automatic workflow to define patient-specific rectal sub-regions (RSR) involved in rectal bleeding (RB) in case of prostate cancer radiotherapy. A multi-atlas database spanning the large rectal shape variability was built from a population of 116 individuals. Non-rigid registration followed by voxel-wise statistical analysis on those templates allowed finding RSR likely correlated with RB (from a learning cohort of 63 patients). To define patient-specific RSR, weighted atlas-based segmentation with a vote was then applied to 30 test patients. Results show the potentiality of the method to be used for patient-specific planning of intensity modulated radiotherapy (IMRT).