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 3 lesions 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.