F-18 Sodium Fluoride in Prostate Cancer

Background: \- Sodium fluoride (NaF) is a common compound that is found in various foods and can be used to increase bone strength. When this compound is added to a small dose of radiation (F-18), it collects in the bones, with higher amounts in areas where the bone is rapidly changing, such as the site of a healing fracture or a tumor. By giving F-18 NaF before a combined positron emission tomography/ computed tomography (PET/CT) scan, researchers hope to be able to better measure the changes in the bone that may indicate that a certain type of cancer (such as prostate cancer) has spread to the bones. Objectives: * To evaluate the effectiveness of F-18 NaF in imaging studies to measure bone tumors and their change over time and compare with clinical course, in individuals with prostate cancer. * To determine the smallest amount of change in the bone tumors that F-18 NaF can accurately measure. Eligibility: \- Men at least 18 years of age who have been diagnosed with prostate cancer and have had imaging studies to determine whether the cancer has spread to their bones. Both patients with and without known bone involvement will be enrolled. Design: * Participants will be screened with a physical examination, medical history, and imaging studies, and will provide baseline blood samples to evaluate kidney function. * For the study, participants will have two F-18 NaF PET/CT scans on separate days for baseline. These repeat scans will be used to determine the amount of change that is due to the imaging process alone (i.e. not due to the disease getting better or worse. Participants will receive a dose of F-18 NaF intravenously, and will have PET/CT scanning over the body (mid ear to upper thighs) over 1 hour, the body followed by a complete whole-body PET/CT scan at approximately 2 hours after F-18 NaF injection. Participants will be watched closely for side effects from the F-18 NaF until the scans are done, and will be asked to drink plenty of water to void the F-18 NaF from the body after the scans. * As a followup study, participants will have two more F-18 NaF PET/CT scans, one 4 to 8 months after the first scans and then one 10 to 14 months after the first scans. Participants will provide additional blood samples before the followup scans.