Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Rotop Pharmaka GmbH, Dresden, Germany.
Mol Imaging Biol. 2018 Aug;20(4):650-658. doi: 10.1007/s11307-018-1160-8.
[Ga]Trishydroxypyridinone (THP)-prostate-specific membrane antigen (PSMA) is a novel tracer that can be labeled in one step by cold reconstitution of a kit with unprocessed generator eluate, targeting PSMA via the lysine-urea-glutamate (KuE) motif. The aim of this study was to evaluate the human imaging characteristics of [Ga]THP-PSMA.
[Ga]THP-PSMA positron emission tomography (PET)/x-ray computed tomography (CT) was performed in 25 patients with biochemical recurrence after radical prostatectomy for prostate cancer. Urinary and biliary excretion and tumor lesion uptake were quantified using standardized uptake values (SUVs). Imaging characteristics were assessed in terms of non-target organ uptake, background activity, target-to-background ratios (TBRs) of tumor lesions, and frequency of bladder halo artifacts. Findings were compared to a matched cohort of 25 patients undergoing PET/CT with the established agent [Ga]PSMA I&T.
Physiologic uptake of [Ga]THP-PSMA was significantly lower in salivary glands (P < 0.0001), liver (P < 0.0001), spleen (P < 0.0001), and kidneys (P < 0.0001) than with [Ga]PSMA I&T. While biliary tracer excretion of [Ga]THP-PSMA was negligible, urinary tracer excretion of [Ga]THP-PSMA was fast, and significantly higher than for [Ga]PSMA I&T, contributing to a higher frequency of bladder artifacts. Malignant lesion uptake of [Ga]THP-PSMA assessed as either SUV or TBR was significantly lower than with [Ga]PSMA I&T.
[Ga]THP-PSMA yields suitable in vivo uptake characteristics. The simplified synthesis method for [Ga]THP-PSMA may facilitate wider application and higher patient throughput with PSMA imaging. However, direct intraindividual comparison studies are needed to assess the relative performance of [Ga]THP-PSMA vs other PSMA ligands in terms of clinical detection rate and image quality.
[Ga]三羟吡啶酮（THP）-前列腺特异性膜抗原（PSMA）是一种新型示踪剂，可通过冷再组装试剂盒，使用未加工的发生器洗脱液一步标记，通过赖氨酸-脲-谷氨酸（KuE）基序靶向 PSMA。本研究旨在评估[Ga]THP-PSMA 的人体成像特征。
对 25 例前列腺癌根治术后生化复发的患者进行[Ga]THP-PSMA 正电子发射断层扫描（PET）/X 射线计算机断层扫描（CT）检查。使用标准化摄取值（SUV）定量测定尿和胆汁排泄及肿瘤病变摄取。根据非靶器官摄取、背景活性、肿瘤病变的靶/背景比（TBR）以及膀胱晕环伪影的频率来评估成像特征。将这些发现与 25 例接受经证实的[Ga]PSMA I&T 药物的 PET/CT 检查的匹配队列进行比较。
与[Ga]PSMA I&T 相比，[Ga]THP-PSMA 在唾液腺（P<0.0001）、肝脏（P<0.0001）、脾脏（P<0.0001）和肾脏（P<0.0001）中的生理性摄取显著降低。[Ga]THP-PSMA 的胆汁示踪剂排泄可以忽略不计，而[Ga]THP-PSMA 的尿示踪剂排泄较快，明显高于[Ga]PSMA I&T，导致更高频率的膀胱伪影。[Ga]THP-PSMA 摄取的恶性病变摄取评估为 SUV 或 TBR 均显著低于[Ga]PSMA I&T。
[Ga]THP-PSMA 产生了合适的体内摄取特征。[Ga]THP-PSMA 的简化合成方法可能会促进 PSMA 成像的更广泛应用和更高的患者吞吐量。然而，需要进行直接的个体内比较研究，以评估[Ga]THP-PSMA 与其他 PSMA 配体在临床检出率和图像质量方面的相对性能。
