Background: Prostate cancer is the second leading cause of cancer-related death in American men. The disease recurs in up to 50,000 men each year after their early-stage disease was treated; however, at this stage, imaging scans are often unable to find the disease in the body. In this natural history study, researchers want to find out if a new radiotracer (18F-DCFPyL) injected before positron emission tomography (PET) imaging can help identify sites in the body with cancer.

Objective: To learn more about how 18F-DCFPyL PET/CT scans detect change over time in men with recurrent prostate cancer.

Eligibility: Men aged 18 and older with prostate cancer that returned after treatment.

Design: Participants will be screened with blood tests. They will also have a bone scan and a computed tomography (CT) scans of the chest, abdomen, and pelvis. Participants will have an initial study visit. They will have a physical exam and blood tests. They will have a PET/CT scan with 18F-DCFPyL. The radiotracer will be injected into a vein; this will take about 20 seconds. The PET/CT scan will be done 1 to 2 hours later. Participants will lie still on a scanner table while a machine captures images of their body. The scan will take 45 minutes. Participants will return for blood tests every 3 months. Participants will return for additional scans with 18F-DCFPyL on this schedule: Once a year if their previous scan was negative for prostate cancer. Every 6 months if their previous scan was positive for prostate cancer. Participants may be in the study up to 5 years.