Advanced Imaging for Radiotherapy Treatment Planning and Guidance for Low-Intermediate Risk Prostate Cancer (Margin)

The integration of magnetic resonance imaging (MRI) in the treatment planning process for prostate cancer will reduce uncertainties in delineation of the prostate gland, and will enable delineation of the urethra, penile bulb, and internal pudendal artery. The integration of daily cone-beam computed tomography (CBCT) will markedly reduce set-up uncertainties, thereby reducing the minimum planning target volume (PTV) margin. By combining MRI simulation and daily CBCT, and by adapting radiation delivery accordingly, the investigators will reduce dose delivered to the rectum, bladder, urethra, and erectile structures. In this study, the investigators seek to determine whether this dose reduction translates to improved patient outcomes. In a prospective, 2-stage design, up to 190 patients will be enrolled. In the first stage, advanced imaging will be integrated without altering dose planning techniques. Stage 2 will reduce dose delivered to normal tissues, and will collect toxicity outcome measures. This clinical trial will be conducted over 3 years.

Inclusion Criteria: Low or intermediate risk localized prostate cancer: * Gleason score ≤ 7 * PSA \