The purpose of this study is to determine whether imaging with 18F-choline PET/CT can provide information that may help guide subsequent investigational or clinical treatments for patients with advanced (hormone-refractory) metastatic prostate cancer.

Patients who meet eligibility criteria and are enrolled will undergo whole-body imaging with 18F-choline PET/CT at 3 time points during the course of treatment that is indicated for castrate resistant prostate cancer. The 1st PET/CT scan is performed at baseline before treatment initiation. The 2nd and 3rd scans are performed at two other treatment-releated timepoints or at approximately 1 month and 3 months after treatment initiation. Change in lesion 18F-choline uptake from baseline measured at each time point will be determined. Cancer 18F-choline uptake will be evaluated as a marker of therapeutic response in comparison to PSA response and symptom scores. Treatment-related changes in tumor 18F-choline uptake occur will be studied after the second and third PET scans to determine the acuity by which changes in tumor 18F-choline uptake can be expected following specific treatments for castrate-resistant prostate cancer. The study evaluates a diagnostic intervention and the treatments themselves are not considered part of the investigation. All treatment decisions will be made independent of the study and must be deemed clinically-warranted by a treating physician.

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.