Background: The maximum standardised uptake value (SUVmax) can potentially be affected by the uptake period during PSMA PET imaging. The optimal image acquisition period for 2-(3-{1-carboxy-5-[(6-18F-fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (18F-DCFPyL)PSMA PET/CT is yet to be established. This study aims to evaluate the effect of the uptake period on the SUVmaxin diagnosing localised, clinically significant prostate cancer using18F-DCFPyL-PSMA PET/CT. Methods: Sixty biopsy-naive men with one or more PI-RADS 4 or 5 lesions of at least 10 mm on multiparametric MRI (mpMRI) were enrolled to undergo18F-DCFPyL-PSMA PET/CT. SUVmaxwas prospectively measured following an uptake period of 60, 90 and 120 min post injection of18F-DCFPyL-PSMA radiotracer. Concordance with biopsy results or final histopathology was recorded. Results: Mean absolute differences in SUVmaxat 60 vs. 90, 60 vs. 120, and 90 vs. 120 min uptake periods were 3.23 (SD 4.76), 4.53 (SD 7.33), and 3.24 (SD 4.56), respectively. This represents a statistically significant systematic increase in SUVmax(p-value < 0.001) with increasing uptake period. The interval between the uptake period of 60 vs. 120 min represented the largest SUVmaxchange of 29.98%. Conclusions: The SUVmaxis a dynamic variable significantly affected by uptake period. Our study supports image acquisition at 120 min following injection of18F-DCFPyL radiotracer. Further studies are needed to determine if this acquisition period can be applied to other Fluorine-18 based PSMA radiotracers.
背景：PSMA PET成像中，最大标准化摄取值（SUVmax）可能受摄取时间影响。2-(3-{1-羧基-5-[(6-18F-氟代吡啶-3-羰基)-氨基]-戊基}-脲基)-戊二酸（18F-DCFPyL）PSMA PET/CT的最佳图像采集时间尚未明确。本研究旨在评估使用18F-DCFPyL-PSMA PET/CT诊断局限性临床显著前列腺癌时，摄取时间对SUVmax的影响。方法：纳入60例经多参数MRI（mpMRI）检测发现至少一处直径≥10 mm的PI-RADS 4或5级病灶且未接受过活检的男性患者，行18F-DCFPyL-PSMA PET/CT检查。在注射18F-DCFPyL-PSMA放射性示踪剂后60、90和120分钟分别前瞻性测量SUVmax，并记录与活检结果或最终组织病理学的一致性。结果：60分钟与90分钟、60分钟与120分钟、90分钟与120分钟摄取时间段的SUVmax平均绝对差值分别为3.23（标准差4.76）、4.53（标准差7.33）和3.24（标准差4.56）。统计分析显示SUVmax随摄取时间延长呈系统性显著增加（p值<0.001），其中60分钟与120分钟摄取时间间隔的SUVmax变化幅度最大，达29.98%。结论：SUVmax是受摄取时间显著影响的动态变量。本研究支持在注射18F-DCFPyL示踪剂后120分钟进行图像采集。未来需进一步研究该采集时间是否适用于其他基于氟-18的PSMA放射性示踪剂。
Impact of Uptake Period on18F-DCFPyL-PSMA PET/CT Maximum Standardised Uptake Value
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