Lawal Ismaheel O, Mushtaq Aliza, Jani Ashesh B, Rupji Manali, Dhere Vishal R, Patel Sagar A, Bilen Mehmet A, Patel Pretesh R, Sebastian Nikhil T, Switchenko Jeffrey M, Schuster David M, Marcus Charles
Department of Radiology and Imaging Sciences, Emory University, Atlanta, Georgia;
Department of Nuclear Medicine, University of Pretoria, Pretoria, South Africa.
J Nucl Med. 2025 Feb 3;66(2):230-237. doi: 10.2967/jnumed.124.268574.
Radiopharmaceuticals targeting prostate-specific membrane antigen (PSMA) have emerged as a sensitive tool for PET imaging of prostate cancer (PCa) recurrence. Yet urinary bladder activity may obscure the visualization of prostate bed recurrence. Among the Food and Drug Administration-approved PSMA radiopharmaceuticals, F-flotufolastat (rhPSMA-7.3) has the lowest urinary excreted activity. We investigated the impact of diuresis with intravenous furosemide and oral hydration on bladder activity and PCa recurrence detection in patients with PCa after prostatectomy with biochemical recurrence. This phase II study (NCT05779943) prospectively recruited men with PCa after prostatectomy with a rising prostate-specific antigen (PSA) level of at least 0.1 ng/mL. All patients had 2 F-flotufolastat PET/CT scans, one with 20 mg of furosemide administered intravenously with the radiotracer and the other without. SUV, SUV, and bladder volume were compared between the with- and without-furosemide PET/CT studies. PCa lesion detection was compared between the 2 sets of scans. Twenty men with a median PSA of 0.61 ng/mL (interquartile range, 0.18-1.15) completed both sets of scans. Bladder activity was significantly lower for the with- than the without-furosemide studies, at a median SUV of 4.20 (range, 1.70-19.80) versus 13.35 (range, 3.90-165.4), respectively ( = 0.014), and a median SUV of 2.95 (range, 0.80-17.60) versus 10.00 (range, 1.90-140.00), respectively ( = 0.017). Multivariable analysis demonstrated that both furosemide administration and bladder distention were independent covariates for reduced bladder activity. At the prostate bed region level, the recurrence detection rates were 17 of 20 (85%) and 12 of 20 (60%) for the with- and without-furosemide studies, respectively ( = 0.025). No difference in detection rates was present at the per-patient, pelvic, or extrapelvic regions between the 2 sets of studies. Three of 20 without-furosemide studies had a mild noninterfering peribladder halo artifact, but none had an artifact with furosemide. In men with biochemical recurrence and a PSA level of at least 0.1 ng/mL after prostatectomy for PCa, a strategy with F-flotufolastat PET/CT and concordant low-dose furosemide further reduces urinary bladder intensity and increases local recurrence detection. Even without the use of a diuretic, relative bladder distension alone also reduces bladder activity, though not to the same degree as with a diuretic.
靶向前列腺特异性膜抗原（PSMA）的放射性药物已成为前列腺癌（PCa）复发PET成像的一种敏感工具。然而，膀胱内的放射性可能会掩盖前列腺床复发灶的显影。在食品药品监督管理局批准的PSMA放射性药物中，F-氟托弗司他（rhPSMA-7.3）的尿液排泄放射性最低。我们研究了静脉注射速尿和口服补液利尿对前列腺切除术后生化复发的PCa患者膀胱内放射性及PCa复发检测的影响。这项II期研究（NCT05779943）前瞻性招募了前列腺切除术后前列腺特异性抗原（PSA）水平至少升高0.1 ng/mL的PCa男性患者。所有患者均接受2次F-氟托弗司他PET/CT扫描，一次在注射放射性示踪剂时静脉注射20 mg速尿，另一次不注射。比较了使用和未使用速尿的PET/CT研究之间的SUV、SUV以及膀胱体积。比较了两组扫描之间PCa病灶的检测情况。20名PSA中位数为0.61 ng/mL（四分位间距，0.18 - 1.15）的男性完成了两组扫描。使用速尿组的膀胱内放射性显著低于未使用速尿组，SUV中位数分别为4.20（范围，1.70 - 19.80）和13.35（范围，3.90 - 165.4）（P = 0.014），SUV中位数分别为2.95（范围，0.80 - 17.60）和10.00（范围，1.90 - 140.00）（P = 0.017）。多变量分析表明，速尿给药和膀胱扩张都是降低膀胱内放射性的独立协变量。在前列腺床区域水平，使用速尿组和未使用速尿组的复发检出率分别为20例中的17例（85%）和20例中的12例（60%）（P = 0.025）。两组研究在每位患者、盆腔或盆腔外区域的检出率没有差异。20例未使用速尿的研究中有3例出现轻度不干扰的膀胱周围晕状伪影，但使用速尿的研究中均未出现伪影。对于PCa前列腺切除术后生化复发且PSA水平至少为0.1 ng/mL男性患者而言，F-氟托弗司他PET/CT联合低剂量速尿的策略可进一步降低膀胱放射性强度并提高局部复发的检出率。即使不使用利尿剂，仅相对膀胱扩张也会降低膀胱内放射性，尽管程度不如使用利尿剂时。
