A Study of 68Gallium PSMA-PET/CT Scans in People With Bladder Cancer or Skin Cancer

Inclusion criteria

• for Urothelial Carcinoma Cohort:
• Patients with histologically confirmed metastatic urothelial carcinoma with extrapelvic nodal and/or visceral sites of disease (including lung, liver, bone, or soft tissue)
• At least 1 lesion assessable by FDG PET/CT according to RECIST and PERCIST guidelines where applicable, that are determined suspicious for metastasis by an MSKCC attending radiologist or nuclear medicine physician.
• Karnofsky performance status ≥50% (or ECOG/WHO ≤2)
• Participant is ≥18 years of age
• Patient must be able to understand and is willing to sign a written informed consent document
• Inclusion Criteria for Melanoma Cohort:
• Patients with histologically confirmed metastatic melanoma
• At least 1 metastatic lesion assessable by CT or FDG PET/CT according to RECIST that is determined to be suspicious for metastasis by an MSKCC attending radiologist or nuclear medicine physician
• ECOG \<= 2
• Participant is \>= 18 years of age
• Patient must be able to understand and is willing to sign a written informed consent document

Exclusion criteria

• for Urothelial Carcinoma Cohort:
• Patients with pelvic node-only metastatic disease. If the patient has lymph node only disease, at least one PET-assessable node must be located outside of the pelvis
• Patients with bone only disease
• Unable to lie flat, still, or to tolerate a PET scan
• Patient undergoing active treatment for non-urothelial malignancy, other than skin basal cell or cutaneous superficial squamous cell carcinoma that has not metastasized.
• Patients on a therapeutic clinical trial where PSMA imaging would interfere with the conduct of the trial
• Patients undergoing active surveillance with a known history of non-urothelial malignancies
• Women who are pregnant. All women of childbearing potential must have a documented negative pregnancy test.
• Exclusion Criteria for Melanoma Cohort:
• Unable to lie flat, still, or tolerate PET scan.
• Patient is on another therapeutic trial where PSMA imaging would interfere with the conduct of the trial.
• Women who are pregnant. All women of childbearing potential must have a documented negative pregnancy test.