Sodium Fluoride (NaF) Positron Emission Tomography/Computed Tomography (PET/CT) in Patients With Metastatic Castrate-resistant Prostate Cancer (CRPC) With Microtubule Directed Chemo or AR-directed Therapy

Subjects who will be enrolled will be those who will be starting treatment (as part of standard of care or as part of another trial) with either a microtubule directed chemotherapy regimen (cohort A), or AR-directed therapy (cohort B). All subjects will have a baseline NaF PET/CT scan (baseline #1), performed within days prior to starting either chemotherapy or AR-directed therapy. A subset of subjects (up to 20 subjects per site, 60 total) will undergo a second NaF PET/CT scan (baseline #2) within 1-8 days of the initial scan to determine repeatability of NaF PET/CT scanning. Subjects in cohort A will undergo another NaF PET/CT scan at week 8 (+/- 1 week). Subjects in cohort B will undergo two additional NaF PET/CT scans at weeks 6 and 12 (+/- 1 week).