MR Imaging Based Treatment Planning for Radiotherapy of Prostate Cancer; Final addendum 1 Feb 2007-31 Jan 2008

摘要

The purpose of this investigation is to develop an integrated system based on MRI simulation to improve target delineation, target localization and target motion correction for 3-dimensional conformal radiation therapy (3DCRT) and intensity-modulated radiation therapy (IMRT) of prostate cancer. We have performed studies on the effect of intra-fraction prostate motion using MR cine images and we also have been evaluating the accuracy of a stereotactic body frame for patient immobilization using MRI. We have confirmed that treatment planning dose calculations using MRI-derived homogenous geometry are adequate for patient sizes within 38 cm using the gradient distortion correction (GDC) software (Chen et al 2004a 2004b). We have quantified the residual distortions and developed computer software to reduce them using point-by point corrections for large patients (lateral dimension up to 42 cm, (Chen et al 2006)). We have verified dosimetric accuracy and consistency for MR based IMRT treatment planning for prostate cancer using the Monte Carlo method (Chen et al 2007). We have developed a technique to create MR-based digitally reconstructed radiographs (DRR) for patient initial setup for clinical applications of MR- based treatment planning for prostate IMRT (Chen et al 2007).