This study will use PET scans, which is a type of x-ray test that uses a radiotracer, to see whether these scans may be better able to find places in the body where your prostate cancer may have spread.

Our preliminary studies have shown that whole body FDG-PET imaging identifies areas of abnormal metabolism in a majority of tumor sites in patients with progressive disease and that changes in FDG accumulation parallel changes in PSA after treatment. This suggests that changes in FDG metabolism may provide an early assessment of treatment outcomes. In previous work we established a methodology to examine a radiotracer in patients with progressive disease and abnormal imaging studies, which we have applied to the clinical states of non-castrate and castrate metastatic disease. This design is characterized by:

1) Evaluation of uptake on a site-by-site basis in relation to conventional studies 2) Standardization of uptake values in tumor relative to a normal organ 3) Controlling for progression using standard measures of progression including a rising PSA, new or enlarging lesions on bone or transaxial imaging, and new symptoms of disease. In the present study we are evaluating fluorinated dihydrotestosterone (FDHT) in addition to FDG. FDHT is targeted to the AR and has been shown in preliminary studies to visualize prostate cancers in man. This study will apply our established methods to investigate FDHT imaging in patients with progressive prostate cancer. In the selected cases where tumor is available, we will study associations between FDHT accumulation and AR expression.

Inclusion Criteria:

• Patients with histologically confirmed prostate cancer.
• Progressive disease manifest by either:
• Imaging modalities:
• Bone Imaging: New osseous lesions on bone imaging (bone scintigraphy or NaF PET scan) and/or MRI or CT: An increase in measurable soft tissue disease, or the appearance of new sites of disease. Or
• Biochemical progression: A minimum of three rising PSA values from a baseline that are obtained 1 week or more apart, or 2 measurements 2 or more weeks apart.
• Visible lesions by either CT, bone imaging, or MRI consistent with disease.
• Informed consent.

Exclusion Criteria:

• Previous anaphylactic reaction to either FDHT or FDG
• Hepatic: Bilirubin > 1.5 x upper limit of normal (ULN), AST/ALT >2.5 x ULN, albumin < 2 g/dl, and GGT > 2.5 x ULN IF Alkaline phosphatase > 2.5 x ULN
• Renal: Creatinine >1.5 x ULN or creatinine clearance < 60 mL/min