Advances in medical imaging, and their integration in the treatment planning and daily guidance of radiotherapy, stand to improve the therapeutic ratio. Improved imaging can reduce uncertainties by 1) improving the accuracy and reproducibility of organ or tumor delineation, and 2) guiding and adapting delivery to account for organ motion. This paradigm has been widely accepted in the radiotherapy community, and much research has addressed the technical and dosimetric aspects for a sound clinical implementation. However, direct evidence of a clinical translation to improved patient outcomes is limited. In this study, we hypothesize that the integration of advanced imaging for treatment planning and guidance will safely enable a reduction of dose delivered to normal tissues, and will improve toxicity and quality of life (QOL) outcomes in patients receiving external beam radiotherapy for low or intermediate risk prostate cancer.