211At is one of the ideal nuclides for targeted radionuclide therapies (TRTs). Meta-[211At]astatobenzylguanidine (211At-MABG) has been proposed for the treatment of pheochromocytoma. To effectively use these radiopharmaceuticals, dosimetry must be performed. It is important to determine the absorbed doses of free 211At and 211At-MABG to determine the organs that may be at risk when using TRTs. The aim of this study was to estimate human dosimetry from preclinical biodistribution of free 211At and 211At-MABG in various organs in normal mice. Male C57BL/6 N mice were administered 0.13 MBq of free 211At or 0.20 MBq of 211At-MABG by tail-vein injection. The mice were sacrificed at 5 min, and at 1, 3, 6, and 24 h after the injection (n = 5 for each group). The percentage of injected activity per mass in organs and blood (%IA/g) was determined. The human absorbed doses of free 211At and 211At-MABG were calculated using the Organ Level INternal Dose Assessment/EXponential Modeling (OLINDA/EXM) version 2.0 and IDAC-Dose 2.1. High uptake of free 211At was observed in the lungs, spleen, salivary glands, stomach, and thyroid. The absorbed doses of free 211At in the thyroid and several tissues were higher than those of 211At-MABG. The absorbed doses of 211At-MABG in the adrenal glands, heart wall, and liver were higher than those of free 211At. The absorbed doses of 211At-MABG in organs expressing the norepinephrine transporter were higher than those of free 211At. In addition, the biodistribution of free 211At was different from that of 211At-MABG. The absorbed dose of free 211At may help predict the organs potentially at risk during TRTs using 211At-MABG due to deastatination.

中文翻译：

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使用正常小鼠的临床前生物分布估算游离 211At 和间[211At]astatobenzylguanidine (211At-MABG) 的人体剂量测定。


211At是靶向放射性核素治疗（TRT）的理想核素之一。间[211At]迷迭香苄基胍（211At-MABG）已被提议用于治疗嗜铬细胞瘤。为了有效地使用这些放射性药物，必须进行剂量测定。确定游离 211At 和 211At-MABG 的吸收剂量对于确定使用 TRT 时可能面临风险的器官非常重要。本研究的目的是根据游离 211At 和 211At-MABG 在正常小鼠各个器官中的临床前生物分布来估计人体剂量测定。通过尾静脉注射向雄性C57BL/6N小鼠施用0.13MBq的游离211At或0.20MBq的211At-MABG。注射后 5 分钟、1、3、6 和 24 小时处死小鼠（每组 n = 5）。测定器官和血液中单位质量注射活性的百分比(%IA/g)。使用器官水平内部剂量评估/指数模型 (OLINDA/EXM) 2.0 版和 IDAC-Dose 2.1 计算人体吸收的游离 211At 和 211At-MABG 剂量。在肺、脾、唾液腺、胃和甲状腺中观察到游离 211At 的大量摄取。甲状腺和一些组织中游离211At的吸收剂量高于211At-MABG。 211At-MABG在肾上腺、心壁和肝脏中的吸收剂量高于游离211At。表达去甲肾上腺素转运蛋白的器官中 211At-MABG 的吸收剂量高于游离 211At。此外，游离211At的生物分布与211At-MABG不同。游离 211At 的吸收剂量可能有助于预测在使用 211At-MABG 进行 TRT 期间由于脱靶而可能面临风险的器官。