PRIMARY OBJECTIVE:~I. To determine if administering 20 mg furosemide intravenously (IV) at the time of radiotracer injection significantly reduces bladder activity compared with the same patient scanned without furosemide as internal control.~SECONDARY OBJECTIVES:~I. To compare detection rates of recurrent disease in blinded interpretations between the furosemide and non-furosemide 18FrhPSMA-7.3 PET/CT scans, with patients serving as their own internal controls.~II. To compare reader confidence in identifying prostate bed and other recurrent lesions on a 18F-rhPSMA-7.3 PET/CT with furosemide compared with 18F-rhPSMA-7.3 PET/CT without furosemide.~OUTLINE:~Patients receive 18F-rhPSMA 7.3 tracer IV and then undergo PET-CT scans with and without furosemide IV on study.
This phase II trial evaluates Fluorine-18 radiohybrid prostate-specific membrane antigen (18F- rhPSMA)-7.3 positron emission tomography (PET)/computed tomography (CT) scans with and without furosemide for the reduction of bladder activity in patients with prostate cancer that has come back (recurrent) based on elevated levels of prostate-specific antigen (PSA) in the blood (biochemical) after prostate surgery (prostatectomy). Furosemide is a diuretic substance that increases the urine flow into the bladder, thereby decreasing the level of radioactivity within the bladder, which may help to see any abnormal areas that could be masked by the radioactivity within the bladder. PET is an established imaging technique that utilizes small amounts of radioactivity attached to very minimal amounts of tracer, in the case of this research, rhPSMA ligand. CT utilizes x-rays that traverse body from the outside. CT images provide an exact outline of organs and potential inflammatory tissue where it occurs in patient's body. Adding furosemide to 18F-rhPSMA 7.3 PET/CT scans may help to better detect and treat patients with biochemically recurrent prostate cancer.