Yang Dae-Myoung, Li Fiona, Bauman Glenn, Chin Joseph, Pautler Stephen, Moussa Madeleine, Rachinsky Irina, Valliant John, Lee Ting-Yim
Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada.
Robarts Research Institute, University of Western Ontario, 1151 Richmond St, London, ON, N6A 5B7, Canada.
EJNMMI Res. 2021 Jan 4;11(1):2. doi: 10.1186/s13550-020-00735-w.
Identification of the dominant intraprostatic lesion(s) (DILs) can facilitate diagnosis and treatment by targeting biologically significant intra-prostatic foci. A PSMA ligand, [F]DCFPyL (2-(3-{1-carboxy-5-[(6-[F]fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid), is better than choline-based [F]FCH (fluorocholine) in detecting and localizing DIL because of higher tumour contrast, particularly when imaging is delayed to 1 h post-injection. The goal of this study was to investigate whether the different imaging performance of [F]FCH and [F]DCFPyL can be explained by their kinetic behaviour in prostate cancer (PCa) and to evaluate whether DIL can be accurately detected and localized using a short duration dynamic positron emission tomography (PET).
19 and 23 PCa patients were evaluated with dynamic [F]DCFPyL and [F]FCH PET, respectively. The dynamic imaging protocol with each tracer had a total imaging time of 22 min and consisted of multiple frames with acquisition times from 10 to 180 s. Tumour and benign tissue regions identified by sextant biopsy were compared using standardized uptake value (SUV) and tracer kinetic parameters from kinetic analysis of time-activity curves.
For [F]DCFPyL, logistic regression identified K and k as the optimal model to discriminate tumour from benign tissue (84.2% sensitivity and 94.7% specificity), while only SUV was predictive for [F]FCH (82.6% sensitivity and 87.0% specificity). The higher k (binding) of [F]FCH than [F]DCFPyL explains why [F]FCH SUV can differentiate tumour from benign tissue within minutes of injection. Superior [F]DCFPyL tumour contrast was due to the higher k/k (more rapid washout) in benign tissue compared to tumour tissue.
DIL was detected with good sensitivity and specificity using 22-min dynamic [F]DCFPyL PET and avoids the need for delayed post-injection imaging timepoints. The dissimilar in vivo kinetic behaviour of [F]DCFPyL and [F]FCH could explain their different SUV images. Clinical Trial Registration NCT04009174 (ClinicalTrials.gov).
识别前列腺内主要病变（DILs）有助于通过靶向前列腺内具有生物学意义的病灶来促进诊断和治疗。一种前列腺特异性膜抗原（PSMA）配体，[F]DCFPyL（2-(3-{1-羧基-5-[(6-[F]氟吡啶-3-羰基)-氨基]-戊基}-脲基)-戊二酸），在检测和定位DIL方面优于基于胆碱的[F]FCH（氟胆碱），因为其肿瘤对比度更高，尤其是在注射后延迟至1小时进行成像时。本研究的目的是探讨[F]FCH和[F]DCFPyL不同的成像性能是否可以通过它们在前列腺癌（PCa）中的动力学行为来解释，并评估使用短时间动态正电子发射断层扫描（PET）是否能够准确检测和定位DIL。
分别对19例和23例PCa患者进行了动态[F]DCFPyL和[F]FCH PET评估。每种示踪剂的动态成像方案总成像时间为22分钟，由多个采集时间从10秒到180秒的帧组成。使用标准化摄取值（SUV）和从时间-活性曲线动力学分析中获得的示踪剂动力学参数，对经六分区活检确定的肿瘤和良性组织区域进行比较。
对于[F]DCFPyL，逻辑回归确定K和k为区分肿瘤与良性组织的最佳模型（灵敏度84.2%，特异性94.7%），而对于[F]FCH，只有SUV具有预测性（灵敏度82.6%，特异性87.0%）。[F]FCH比[F]DCFPyL更高的k（结合）解释了为什么[F]FCH SUV在注射后几分钟内就能区分肿瘤与良性组织。[F]DCFPyL更好的肿瘤对比度是由于与肿瘤组织相比，良性组织中更高的k/k（更快的洗脱）。
使用22分钟动态[F]DCFPyL PET能够以良好的灵敏度和特异性检测到DIL，并且无需延迟注射后的成像时间点。[F]DCFPyL和[F]FCH在体内不同的动力学行为可以解释它们不同的SUV图像。临床试验注册号NCT04009174（ClinicalTrials.gov）。
