Early Changes In Multiparametric MRI In Prostate Cancer

If the participant chooses to take part in this research study, the participant will have 3 follow up prostate MRIs during a 6 month time period, while the participant is having their ADT/EBRT treatment. These follow-up prostate MRIs will use a standard imaging protocol without the use of an endorectal coil. The participant will also have a total of 4 blood samples to measure serum PSA. 1-2 mls (just less than ½ teaspoon) will be taken for each sample. Research Study Plan * Baseline Visit (routine standard of care screening visit): PSA blood test and prostate MRI * Visit 1 (8 weeks after starting ADT): PSA blood test and prostate MRI * Visit 2 (6 weeks after starting EBRT): PSA blood test and prostate MRI * Visit 3 (on last day of EBRT): PSA blood test * Visit 4 (6 months after starting ADT): PSA blood test and prostate MRI Planned Follow-up: The investigator would like to keep track of the participant's prostate cancer status while they continue to see their doctor at DFCI. The investigators would like to do this by collecting the following data from the participant's medical records, to look at long-term outcome of their ADT/EBRT treatment. * PSA values * Clinical results of your treatment. The investigator will not contact the participant to obtain this information.