胆囊收缩素 2 受体 (CCK2R) 是甲状腺髓样癌成像和治疗的一个有前景的靶点，因为它在超过 90% 的肿瘤细胞中过度表达。 68Ga-DOTA-CCK-66是最近推出的一种对CCK2R具有选择性的PET示踪剂，在临床前实验中显示出良好的体内药代动力学。为了进一步研究该示踪剂在人体中的安全性和适用性，对全身分布和辐射剂量测定进行了评估。 6 名有甲状腺髓样癌病史的患者静脉注射 169 ± 19 MBq 68Ga-DOTA-CCK- 66.注射示踪剂后 10 分钟、1 小时、2 小时和 4 小时采集全身 PET/CT 扫描。确定每个器官的时间-活性曲线，并使用 OLINDA/EXM 计算平均器官吸收剂量和有效剂量。注射 150 MBq 标准活性​​的 68Ga-DOTA-CCK-66 导致有效剂量为 4.5 ± 0.9毫西弗。吸收器官剂量最高的是膀胱壁（40 mGy）和胃（15 mGy），其次是肾脏（6 mGy），以及肝脏和脾脏（各 3 mGy）。在 6 名患者中的 2 名中可以检测到表达 CCK2R 的肿瘤表现，包括淋巴结、骨和肝转移。 68Ga-DOTA-CCK-66 表现出良好的剂量测定。除了胃的生理受体表达之外，无法观察到其他相关的示踪剂积累，这使得该器官在使用 177Lu-DOTA-CCK-66 进行后续放射性配体治疗时处于危险之中。版权所有 © 2024 Wolters Kluwer Health, Inc. 保留所有权利。

Cholecystokinin 2 receptor (CCK2R) is a promising target for imaging and treatment of medullary thyroid cancer due to its overexpression in over 90% of tumor cells. 68Ga-DOTA-CCK-66 is a recently introduced PET tracer selective for CCK2R, which has shown favorable pharmacokinetics in vivo in preclinical experiments. In order to further investigate safety and suitability of this tracer in the human setting, whole-body distribution and radiation dosimetry were evaluated.Six patients with a history of medullary thyroid cancer were injected intravenously with 169 ± 19 MBq of 68Ga-DOTA-CCK-66. Whole-body PET/CT scans were acquired at 10 minutes, 1 hour, 2 hours, and 4 hours after tracer injection. Time-activity curves per organ were determined, and mean organ-absorbed doses and effective doses were calculated using OLINDA/EXM.Injection of a standard activity of 150 MBq of 68Ga-DOTA-CCK-66 results in an effective dose of 4.5 ± 0.9 mSv. The highest absorbed organ doses were observed in the urinary bladder wall (40 mGy) and the stomach (15 mGy), followed by the kidneys (6 mGy), as well as the liver and the spleen (3 mGy each). CCK2R-expressing tumor manifestations could be detected in 2 of the 6 patients, including lymph node, bone, and liver metastases.68Ga-DOTA-CCK-66 exhibits a favorable dosimetry. Beyond physiologic receptor expression of the stomach, no other relevant tracer accumulation could be observed, rendering this organ at risk in case of subsequent radioligand therapy using 177Lu-DOTA-CCK-66.Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.