[18F]-Fluoro-2-Deoxy-D-Glucose and -[18F] Dihydro-Testosterone Pet Imaging in Patients With Progressive Prostate or Salivary Gland Cancer

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 Salivary Gland Cancers Inclusion Criteria: * Histologically proven diagnosis of salivary cancer with AR expression detected by immunohistochemistry * Measurable disease as defined by RECIST v1.1 criteria * Locally advanced/unresectable (as determined by local surgeon) OR metastatic disease. * Age ≥ 18 years * ECOG performance status 0 or 1 * AST/ALT \< 3xULN * No prior AR-targeted therapy (Exception: AR-targeted therapy administered in the adjuvant setting and with disease recurrence more than 6 months since treatment completion) Exclusion Criteria: * Uncontrolled or untreated brain metastases * Class 3 or 4 congestive heart failure * Uncontrolled hypertension (systolic BP \>170 mmHg or diastolic BP \>105 mmHg at screening) * Vascular or ischemic event within 6 months of study registration.