RecruitingPhase 1Drug trialA Study of 68Gallium PSMA-PET/CT Scans in People With Bladder Cancer or Skin CancerThe purpose of this study is to see whether 68Gallium PSMA-PET/CT scans are an effective way to detect sites of cancer in people with metastatic bladder cancer or skin cancer. The study researchers want to learn if a 68Gallium PSMA PET/CT scan will work better, the same, or not as well as the PET/CT scans doctors usually use for imaging bladder cancer or skin cancer (FDG-PET/CT scan).