Large-scale Retrospective Monte Carlo Dosimetric Study for Permanent Implant Prostate Brachytherapy

TG43sim typically overestimates the target and OAR doses by several percent, on average, compared with MCref. The considerable variation in the relative TG43sim and MCref doses between patients, and the larger dose differences for patients with calcification, suggests that clinical adoption of Monte Carlo dose calculations for permanent implant prostate brachytherapy should be pursued. The substantial sensitivity of the Monte Carlo dose calculations to the patient modelling approach supports the adoption of a consensus modelling scheme, such as MCref described in the present study, to ensure consistency of practice.