Forced diuresis may improve readability of 2-(3-(1-carboxy-5-[(6-[F]fluoro-pyridine-3-carbonyl)-amino]-pentyl)-ureido)-pentanedioic acid (F-DCFPyL) PET/computed tomography (CT) by reducing focal ureteral activity. A total of 40 patients received furosemide simultaneously with F-DCFPyL (cohort 1) and 40 patients received furosemide 85 min after F-DCFPyL administration (cohort 2). The frequency of occurrence of activity depositions in ureters and halo artefacts near the kidneys and bladder was measured, as well as intensity of F-DCFPyL uptake in kidneys and bladder. At 120 min after injection of F-DCFPyL, a significantly lower number of F-DCFPyL depositions in ureters was found in cohort 2. Moreover, F-DCFPyL uptake in kidneys and bladder was significantly lower in this cohort; however, the occurrence of halo artefacts was similar in both groups. Administration of furosemide may improve interpretation of F-DCFPyL PET/CT as it results in less activity depositions in ureters. However, the effect depends on the timing of furosemide administration in relation to F-DCFPyL administration and PET/CT acquisition time. Acquisition of PET-images 120 min after F-DCFPyL administration benefits from late furosemide administration (85 min after injection).