Normally, some patients with prostate cancer undergo imaging tests to determine the extent (spread) of their disease. These imaging tests often give good information, but not in all patients and not every time. This study deals with a new imaging test known as F-DCFPyL-Prostate-specific Membrane Antigen (PSMA) Positron Emission Tomography (PET), or F-DCFPyL-PSMA PET. The objective of this study is to evaluate safety and usefulness of using F-DCFPyL in detecting recurrent/metastatic prostate cancer. The F-DCFPyL PET imaging technique is used in some parts of the world but is not currently standard imaging care. Better understanding how this new imaging test performs in identifying recurrent/metastatic prostate cancer may lead to better management of prostate cancer patients in the future.