Pilot of 18F-DCFPyL-PSMA PET in mCRPC Patients Receiving 117Lu-Vipivotide Tetraxetan

This study is using a new type of specialized PET scan (called 18F-DCFPyL PSMA PET) to better understand how prostate cancer responds to a radioactive treatment called Lutetium-177 (Lu-177 PSMA therapy). Researchers want to see if this improved scan gives more accurate information about where the cancer is compared to the standard scan. **You may be eligible if...** - You are a man aged 18 or older with confirmed prostate cancer - You are already scheduled to receive standard-of-care Lu-177 PSMA therapy (a targeted radioactive treatment) - A prior PSMA scan within the last 120 days showed at least one cancer lesion - You are willing and able to follow study procedures **You may NOT be eligible if...** - You have uncontrolled serious illness (infections, heart failure, or irregular heart rhythms) - You are severely claustrophobic and cannot tolerate a PET/CT scan - You have had allergic reactions to similar imaging agents Talk to your doctor to see if this trial is right for you.