Gallium Ga 68 DOTA-NeoBOMB1 and Gallium Ga 68 PSMA-R2 PET/MRI in Diagnosing Participants With Recurrent Prostate Cancer

PRIMARY OBJECTIVES: I. To evaluate gallium Ga 68 DOTA-NeoBOMB1 (68Ga-NeoBOMB1) and gallium Ga 68 PSMA-R2 (68Ga-PSMA R2) PET/MRI for detection of recurrent prostate cancer after initial therapy in patients meeting the criterion of biochemical recurrence. OUTLINE: Participants are randomized to 1 of 2 arms. ARM I: Participants receive gallium Ga 68 DOTA-NeoBOMB1 intravenously (IV) and 45 minutes later, undergo PET/MRI. Within 2 weeks, participants receive gallium Ga 68 PSMA-R2 IV then undergo PET/MRI 45-60 minutes later. ARM II: Participants receive gallium Ga 68 PSMA-R2 IV and 45-60 minutes later undergo PET/MRI. Within 2 weeks, participants receive gallium Ga 68 DOTA-NeoBOMB1 IV then undergo PET/MRI 45 minutes later. After completion of study, participants are followed up at 12 months.