Haupt Fabian, Dijkstra Lotte, Alberts Ian, Sachpekidis Christos, Fech Viktor, Boxler Silvan, Gross Tobias, Holland-Letz Tim, Zacho Helle D, Haberkorn Uwe, Rahbar Kambiz, Rominger Axel, Afshar-Oromieh Ali
Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Department of Radiology, Bern University Hospital, Bern, Switzerland.
Eur J Nucl Med Mol Imaging. 2020 Mar;47(3):624-631. doi: 10.1007/s00259-019-04548-5. Epub 2019 Nov 1.
Ga-PSMA-11 PET/CT is commonly performed at 1 h post injection (p.i.). However, various publications have demonstrated that most prostate cancer (PC) lesions exhibit higher contrast at later imaging. The aim of this study was to compare the "common" protocol of Ga-PSMA-11 PET/CT with a modified protocol.
In 2017, we used the following scanning protocol for Ga-PSMA-11 PET/CT in patients with recurrent PC: acquisition at 1 h p.i. without further preparations. From 2018, all scans were conducted at 1.5 h p.i. In addition, patients were orally hydrated with 1 L of water 0.5 h p.i. and were injected with 20 mg of furosemide 1 h p.i. Both protocols including 112 patients (2017) and 156 (modified protocol in 2018) were retrospectively compared. Rates of pathologic scans, maximum standardized uptake values (SUVmax), and tumor contrast (ratio lesion-SUVmax/background-SUVmean) as well as average standardized uptake values (SUVmean) of urinary bladder were analyzed.
Both tumor contrast and tracer uptake were significantly (p < 0.001) higher in the novel protocol. Although statistically not significant, the rates of pathologic scans were also higher in the modified protocol: 76.3% vs. 68.8% for all PSA values including 38.9% vs. 25.0% for PSA < 0.5 ng/ml and 60.0% vs. 56.7% for PSA > 0.5-≤ 2.0 ng/ml. Average SUVmean of the urinary bladder was significantly (p < 0.001) lower with the modified protocol.
The modified protocol, which includes a combination of delayed image acquisition at 1.5 h p.i., hydration, and furosemide resulted in higher tumor contrast and seems to have the potential to increase the rates of pathological scans, especially at low PSA levels.
镓-PSMA-11 PET/CT通常在注射后1小时进行。然而，各种出版物表明，大多数前列腺癌（PC）病变在延迟成像时显示出更高的对比度。本研究的目的是比较镓-PSMA-11 PET/CT的“常规”方案与改良方案。
2017年，我们对复发性PC患者使用以下镓-PSMA-11 PET/CT扫描方案：注射后1小时采集，无需进一步准备。从2018年起，所有扫描均在注射后1.5小时进行。此外，患者在注射后0.5小时口服1升水进行水化，并在注射后1小时注射20毫克速尿。回顾性比较了包括112例患者（2017年）和156例患者（2018年改良方案）的两种方案。分析了病理扫描率、最大标准化摄取值（SUVmax）、肿瘤对比度（病变-SUVmax/背景-SUVmean比值）以及膀胱的平均标准化摄取值（SUVmean）。
新方案中的肿瘤对比度和示踪剂摄取均显著更高（p < 0.001）。虽然在统计学上不显著，但改良方案中的病理扫描率也更高：所有PSA值的病理扫描率分别为76.3%和68.8%，其中PSA < 0.5 ng/ml时分别为38.9%和25.0%，PSA > 0.5-≤ 2.0 ng/ml时分别为60.0%和56.7%。改良方案下膀胱的平均SUVmean显著更低（p < 0.001）。
改良方案包括在注射后1.5小时延迟图像采集、水化和速尿联合应用，可提高肿瘤对比度，似乎有可能提高病理扫描率，尤其是在低PSA水平时。
