99mTc-PSMA-I&S Biodistribution in Patients With Prostate Cancer

This exploratory study conducted under the RDRC program studies the biodistribution of 99mTc-PSMA-I\&S in patients with prostate cancer who undergo pelvic lymph node dissection. Prostate specific membrane antigen (PSMA)-targeted radio-guided surgery uses the preoperative intravenous administration of a PSMA-ligand called PSMA-imaging and surgery (I\&S) labeled with the gamma-emitter radioisotope Technetium-99m (99mTc). Giving 99mTc-PSMA-I\&S may detect PSMA-expressing lymph nodes during surgery using a gamma probe and may help guide doctors to detect prostate cancer that has spread to the lymph nodes.

PRIMARY OBJECTIVE: I. To define the biodistribution of 99mTc-based PSMA imaging and surgery agent (99mTc-PSMA-I\&S) in normal and malignant tissues of patients with prostate cancer (PCa) with histopathology validation, when available. SECONDARY OBJECTIVES: I. To correlate the 99mTc-PSMA-I\&S accumulation within tumor lesions observed by in-vivo single-photon emission computed tomography (SPECT), ex-vivo gamma measurements and level of prostate-specific membrane antigen (PSMA) expression quantified by histopathology, when available. II. To define the best time-point for radio-guided surgery (RGS) with the highest tumor-to-background ratio following 99mTc-PSMA-I\&S administration. OUTLINE: The first 5 patients receive an initial dose of 99mTc-PSMA-I\&S intravenously (IV) followed by 5 SPECT/CT scans at 3-5, 5-20, 17-21, 25-29, and 40-46 hours later. These 5 patients then receive a second dose of 99mTc-PSMA-I\&S IV and then undergo standard of care surgery. All subsequent patients receive one dose of 99mTc-PSMA-I\&S IV before surgery.