Patient description: The patient is a 63-year-old man presenting to the Emergency Department with a history of acute urinary retention in the past 2 days. Abdominopelvic CT scan revealed a large prostate and a bladder filled with urine. He is a candidate for urethral catheterization and TURP. Further evaluation revealed: Post-void residual: 71 mL Prostate volume (TRUS): 63 mL Prostate-specific antigen (PSA) level: 3.5 ng/mL His recent blood chemistry (3 days ago) was normal: Hgb: 13.6 g/dl WBC: 133000 /mm3 Plt: 370000 /ml PT: 12 second PTT: 34 second INR: 0.9 Creatinine: 0.5 mg/dl BUN: 10 mg/dl U/A: Color: yellow Appearance: cloudy PH: 5.3 Specific gravity: 1.010 Glc: 100 Nitrite: negative Ketone: none Leukocyte esterase: negative RBC: negative WBC: 2 WBCs/hpf U/C: negative

Clinical trial eligibility criteria: eligible ages (years): 19.0-99.0,  Prostatic Neoplasm Prostatic Cancer Eastern Cooperative Oncology Group performance status of 2 or less Subjects with high risk prostate cancer (CAPRA score 6 or higher) being considered for curative-intent surgery or radiation therapy (including brachytherapy) Subjects with biopsy confirmed prostate cancer being considered for curative-intent surgery or radiation therapy (including brachytherapy), who have unconfirmed suspicious findings on conventional medical imaging staging examinations Subjects with biochemical recurrence or persistence of prostate cancer following initial curative treatment by radical prostatectomy, with two consecutive PSA values >0.2 ng/ml measured more than 6 weeks after radical prostatectomy. If subjects received subsequent systemic therapy, the most recent PSA measurement prior to PET/CT imaging must be greater than 0.2 ng/mL Subjects with biochemical recurrence or persistence of prostate cancer following initial curative treatment by radical prostatectomy and subsequently treated by salvage radiotherapy or pelvic node dissection, with two consecutive PSA values >0.2 ng/ml. If subjects received subsequent systemic therapy, the most recent PSA measurement prior to PET/CT imaging must be greater than 0.2 ng/mL Subjects with biochemical recurrence of prostate cancer after initial curative therapy with radiation therapy (including brachytherapy), or non-standard local ablative therapy (such as high frequency ultrasound, cryoablation, focal laser ablation, etc.), with a PSA level >2 ng/mL above the nadir after radiation therapy Subjects with advanced castration sensitive or castration resistant prostate cancer being considered for localized treatment (surgery, brachytherapy, radiotherapy) of recurrent or oligometastatic prostate cancer. Castration resistance is defined as a PSA level > 1.0 ng/mL, with 2 consecutive rises above the nadir, in the presence of castrate levels of testosterone (< 1.7 nmol/L) Subjects with metastatic or castration resistant prostate cancer being evaluated for systemic therapy administered in therapeutic clinical trials. The PSA level must be > 1.0 ng/mL, with 2 consecutive rises above the nadir, in the presence of castrate levels of testosterone (< 1.7 nmol/L)  Medically unstable (e.g. acute illness, unstable vital signs) Unable to lie supine for the duration of imaging Unable to provide written consent Exceeds safe weight limit of the PET/CT bed (204.5 kg) or unable to fit through the PET/CT bore (diameter 70 cm) for the use of furosemide Subjects can still participate in the research study and undergo the [68Ga]Ga-PSMA-11 scan if they are unable or unwilling to receive a furosemide injection Subjects with end stage renal disease Subjects with documented history of severe progressive chronic kidney disease (glomerular filtration rate less than 30 mL/min/1.73 m2) Subjects with hypersensitivity to furosemide (Lasix) While cross-reactivity between sulfonamide antibiotics and non-antibiotics has been disproven, subjects who have a history of sulfonamide antibiotics or sulfonylureas may be at a higher risk of allergic reaction to furosemide due to a higher general predisposition to allergic reactions. In those instances, the administration of furosemide is left at the discretion of the local site investigator after discussion with the study subject Subjects with severe hypokalemia, hyponatremia, hypovolemia, dehydration or hypotension