Additional Study Information: The purpose of this study is to see if 18FDCFPyL (PyL) PET/CT scans are able to find prostate cancer tumors. PyL is a radioactive drug (tracer) that targets prostate specific membrane antigen (PSMA). Because PSMA is a protein found mostly on the surface of prostate cancer cells, we are testing to see if PyL will be able to correctly identify prostate cancer. We will also see if we can detect prostate cancer tumor DNA (ctDNA) and cell particles (exosomes) in the blood. We hope that this may one day lead to better tests to evaluate patients with prostate cancer.