68Ga-NODAGA-exendin-4 is a promising tracer for β-cell imaging using PET/CT. Possible applications include preoperative visualization of insulinomas and discrimination between focal and diffuse forms of congenital hyperinsulinism. There is also a significant role for this tracer in extending our knowledge on the role of β-cell mass in the pathophysiology of type 1 and type 2 diabetes by enabling noninvasive quantification of tracer uptake as a measure for β-cell mass. Calculating radiation doses from this tracer is important to assess its safety for use in patients (including young children) with benign diseases and healthy individuals. Methods: Six patients with hyperinsulinemic hypoglycemia were included. After intravenous injection of 100 MBq of the tracer, 4 successive PET/CT scans were obtained at 30, 60, 120, and 240 min after injection. Tracer activity in the pancreas, kidneys, duodenum, and remainder of the body were determined, and time-integrated activity coefficients for the measured organs were calculated. OLINDA/EXM software, version 1.1, was applied to calculate radiation doses using the reference adult male and female models and to estimate radiation doses to children. Results: The mean total effective dose for adults was very low (0.71 ± 0.07 mSv for a standard injected dose of 100 MBq). The organ with the highest absorbed dose was the kidney (47.3 ± 10.2 mGy/100 MBq). The estimated effective dose was 2.32 ± 0.32 mSv for an injected dose of 20 MBq in newborns. This dose decreased to 0.77 ± 0.11 mSv/20 MBq for 1-y-old children and 0.59 ± 0.05 mSv for an injected dose of 30 MBq in 5-y-old children. Conclusion: Our human PET/CT-based dosimetric calculations show that the effective radiation doses from the novel tracer 68Ga-NODAGA-exendin-4 are very low for adults and children. The doses are lower than reported for other polypeptide tracers such as somatostatin analogs (2.1-2.6 mSv/100 MBq) and are beneficial for application as a research tool, especially when repeated examinations are needed.

中文翻译：

---

基于 PET 的 68Ga-NODAGA-Exendin-4 人体剂量测定法，一种 β 细胞成像示踪剂。

68Ga-NODAGA-exendin-4 是一种很有前途的 PET/CT β 细胞成像示踪剂。可能的应用包括胰岛素瘤的术前可视化以及先天性高胰岛素血症的局灶性和弥漫性形式的区分。这种示踪剂在扩展我们对 β 细胞质量在 1 型和 2 型糖尿病的病理生理学中的作用方面也有重要作用，它可以通过无创量化示踪剂摄取来衡量 β 细胞质量。计算该示踪剂的辐射剂量对于评估其用于患有良性疾病的患者（包括幼儿）和健康个体的安全性非常重要。方法：纳入 6 例高胰岛素性低血糖患者。静脉注射 100 MBq 示踪剂后，在注射后 30、60、120 和 240 分钟获得 4 次连续 PET/CT 扫描。测定胰腺、肾脏、十二指肠和身体其他部位的示踪剂活性，并计算测量器官的时间积分活性系数。应用 OLINDA/EXM 软件 1.1 版，使用参考成年男性和女性模型计算辐射剂量，并估计儿童的辐射剂量。结果：成人的平均总有效剂量非常低（100 MBq 标准注射剂量为 0.71 ± 0.07 mSv）。吸收剂量最高的器官是肾脏 (47.3 ± 10.2 mGy/100 MBq)。新生儿注射剂量为 20 MBq 的估计有效剂量为 2.32 ± 0.32 mSv。对于 1 岁儿童，该剂量降至 0.77 ± 0.11 mSv/20 MBq，对于 5 岁儿童注射 30 MBq 剂量，该剂量降至 0.59 ± 0.05 mSv。结论：我们基于人体 PET/CT 的剂量学计算表明，新型示踪剂 68Ga-NODAGA-exendin-4 的有效辐射剂量对成人和儿童来说非常低。该剂量低于其他多肽示踪剂如生长抑素类似物（2.1-2.6 mSv/100 MBq）的报告剂量，有利于作为研究工具的应用，尤其是在需要重复检查时。