Chemotherapy Response Monitoring With 18F-choline PET/CT in Hormone Refractory Prostate Cancer

Inclusion Criteria: 1. Provision of written informed consent. 2. Men, over 18 years of age, with histologically-confirmed diagnosis of prostate cancer 3. History of treatment by complete androgen blockade for greater than 3 months prior to enrollment 4. Progressive disease evidenced by 2 consecutive rises in PSA measured at least 1 week apart, with the absolute value of the latest PSA \> 5.0 ng/ml. 5. A rise in PSA following anti-androgen drug withdrawal, above the last PSA value before withdrawal. 6. Patient has agreed to treatment for hormone-refractory (ie. castrate-resistant) prostate cancer under supervision of a medical oncologist, urologist, radiation oncologist or nuclear medicine physician. Treatments indicated for HRPC are docetaxel-, cabazitaxel-, or mitoxantrone-based chemotherapy, abiraterone, radium-223, enzalutamide, or sipulecuil-T. Exclusion Criteria: 1. Other co-existing malignancies or malignancies diagnosed within the last 5 years with the exception of basal cell carcinoma or superficial transitional cell carcinoma of the bladder. 2. Serious underlying medical conditions that would otherwise impair the patient's ability to undergo imaging. 3. Patient weighs over 350 lbs (due to scanner weight limit). 4. Clinical life expectancy \< 12 weeks. 5. Participated in other radioactive drug studies where estimated total cumulative dose within 1 year is \> 0.05 Sievert for whole body, active blood-forming organs, eye lens, gonads, or 0.15 Sievert for other organs. 6. Concurrent Therapy. Allowed: Prior or concurrent chemotherapy, but must be \> 12 weeks since last treatment at enrollment; prior or concurrent hormonal therapy; prior surgery; prior or concurrent bisphosphonate; prior or concurrent receptor/biologic agent allowed if given on approved study protocol.