Magnetic Resonance (MR) Imaging With Hyperpolarized 13C-Pyruvate +/- 13C,15N-Urea in Patients With Prostate Cancer

This study is testing a new type of MRI scan using a special contrast agent made from carbon — called hyperpolarized 13C-pyruvate — to better visualize prostate cancer and how it responds to radiation treatment. It may help doctors understand whether radiation is working. **You may be eligible if...** - You are 18 or older - You have been diagnosed with prostate cancer (confirmed by biopsy) - You are scheduled for or considering external beam radiation therapy (EBRT) - You are in good general health (ECOG performance status 0 or 1) **You may NOT be eligible if...** - You cannot consent to or comply with study procedures - You do not meet the specific requirements for your assigned study group (e.g., specific PSA levels or cancer stage criteria) Talk to your doctor to see if this trial is right for you.