A Study of 68Ga-PSMA-11 PET Scans in People With Brain Tumors

Inclusion Criteria: * Ability to understand and the willingness to sign (or their legally acceptable representative (LAR) must sign) a written informed consent document * Adults ≥ 18 years old * Suspicion for or histologically or cytologically confirmed and previously treated HGG or brain metastases from a primary extracranial malignancy * Lesion size ≥ 1 cm (for the lesion to be biopsied) * ECOG performance status ≤ 2 (Karnofsky ≥ 60%) * Planned to undergo biopsy/resection of brain lesion Exclusion Criteria: * Inability to undergo a PET scan (e.g., claustrophobia or noncompatible implant in case PET/MR is performed) * Pregnant or nursing female. All women of childbearing potential must have a documented negative serum or urine pregnancy test \<1 week before study. * Uncontrolled, intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiacarrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. * Patients with severe allergy to both iodinated and gadolinium contrast.