Detecting Metastases by PyL PET/CT in Subjects Starting Enzalutamide for Untreated Castration Resistant Prostate Cancer.

Inclusion Criteria: * Histologically confirmed adenocarcinoma of the prostate per original diagnosis, with undergoing androgen deprivation therapy such as prior bilateral orchiectomy or surgical castration or LHRH-agonists/LHRH-antagonists. * Suspected recurrence of prostate cancer based on rising PSA under androgen deprivation therapy. Recurrent castration resistant prostate cancer patients are defined by a rising PSA \>1 ng/mL under ADT or surgical castration and with testosterone castration levels \< 1.7 nM (PCWG3 criteria). * Negative, equivocal findings or oligometastatic disease (\< 5) for prostate cancer on conventional imaging bone scan AND 2) abdomen-pelvis CT/MRI and chest CT or FDG-PET/CT or 18F-NaF PET/CT performed as standard of care workup within 90 days of signing the ICF. * The subject is candidate for second line androgen axis targeted inhibitors such as enzalutamide and planned to receive it. * Life expectancy ≥6 months as determined by the investigator * Able and willing to provide signed informed consent and comply with protocol requirement * PSA doubling time less or equal to 10 months * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at screening. * Able to swallow the study drug and comply with study requirements. Exclusion Criteria: * Subjects administered any high energy (\>300 KeV) gamma-emitting radioisotope within 5 physical half-lives prior to study drug injection. * Receipt of investigational drug therapy for prostate ca…