Geometric and dosimetric impact of anatomical changes for MR-only radiation therapy for the prostate.

Purpose: With the move towards magnetic resonance imaging (MRI) as a primary treatment planning modality option for men with prostate cancer, it becomes critical to quantify the potential uncertainties introduced for MR-only planning. This work characterized geometric and dosimetric intra-fractional changes between the prostate, seminal vesicles (SVs), and organs at risk (OARs) in response to bladder filling conditions.

Materials And Methods: T2-weighted and mDixon sequences (3-4 time points/subject, at 1, 1.