Imaging Biomarkers to Validate Response in Enzalutamide-Treated mCRPC

NaF is a tracer (dye) that will show changes to the cancer in bones. By using this tracer with PET/CT imaging, our ability to evaluate and measure changes in bone lesions could be greatly improved. Participants will have a NaF PET/CT scan within 14 days prior to starting enzalutamide. All subjects will undergo a second NaF PET/CT scan after taking enzalutamide for 12 weeks. The NaF PET/CT obtained at week 12 will be compared to the first NaF PET/CT to identify a bone tumor that is responding (shrinking) and a bone tumor that is not responding (not shrinking).