UNLABELLED (123)I-IMPY (6-iodo-2-(4'-dimethylamino-)phenyl-imidazo[1,2-a]pyridine) is a novel radiopharmaceutical that selectively binds to Alzheimer's disease (AD) amyloid plaques. As a first step toward validating this radiopharmaceutical as an imaging biomarker for AD, we measured the whole-body biokinetics and radiation dosimetry of (123)I-IMPY in AD patients and cognitively normal control subjects. The pharmacologic safety profile of the compound was simultaneously assessed. METHODS The sample included 9 subjects ranging in age from 44 to 80 y. Whole-body images were obtained for each subject (mean +/- SD, 9.0 +/- 3.2 scans per subject) for up to 48 h after the intravenous administration of 185 MBq (5 mCi) of (123)I-IMPY. The fraction of administered activity in 12 regions of interest was quantified from the attenuation-corrected geometric mean counts in conjugate views. Multiexponential functions were iteratively fit to each time-activity curve using a nonlinear, least-squares regression algorithm. These curves were numerically integrated to yield cumulated activity values for source organs. Radiation doses were then estimated with the MIRD technique. RESULTS The radiotracer had no pharmacologic effects (produced no changes in heart rate, blood pressure, or laboratory results) on any of the subjects. Radiation dosimetry estimates indicated that the dose-limiting organ was the gallbladder, which received an average of 0.135 mGy/MBq (range, 0.075-0.198 mGy/MBq). The effective dose equivalent and effective dose for (123)I-IMPY were 0.042 +/- 0.003 mSv/MBq and 0.035 +/- 0.001 mSv/MBq, respectively. The mean effective dose for (123)I-IMPY was similar to that for (111)In-diethylenetriaminepentaacetic acid (0.035 mGy/MBq), less than half that for (111)In-pentetreotide (0.81 mGy/MBq), and approximately twice that for (123)I-IMP (0.018 mGy/MBq). No significant differences were found between men and women or between AD patients and control subjects. CONCLUSION (123)I-IMPY may be a safe radiotracer with appropriate biokinetics for imaging amyloid plaques in AD patients.

中文翻译：

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123I-IMPY的安全性，生物分布和剂量测定：用于诊断阿尔茨海默氏病的新型淀粉样斑块成像剂。

未贴标签的（123）I-IMPY（6-碘-2-（4'-二甲基氨基-）苯基-咪唑并[1,2-a]吡啶）是一种新型的放射性药物，可选择性结合阿尔茨海默氏病（AD）淀粉样蛋白斑块。作为验证这种放射性药物作为AD的成像生物标记物的第一步，我们在AD患者和认知正常对照受试者中测量了（123）I-IMPY的全身生物动力学和辐射剂量。同时评估了该化合物的药理安全性。方法样本包括9位年龄在44至80岁之间的受试者。在静脉内注射（123）I-IMPY 185 MBq（5 mCi）后，在长达48小时内获得了每个受试者的全身图像（平均+/- SD，每个受试者9.0 +/- 3.2扫描）。从共轭视图中的衰减校正后的几何平均数中量化了12个目标区域中所给予活动的比例。使用非线性最小二乘回归算法，将多指数函数迭代拟合到每个时间活动曲线。对这些曲线进行数值积分，以生成源器官的累积活动值。然后用MIRD技术估算辐射剂量。结果放射性示踪剂对任何受试者均无药理作用（心率，血压或实验室结果无变化）。辐射剂量学估计表明，剂量限制器官是胆囊，平均接受0.135 mGy / MBq（范围为0.075-0.198 mGy / MBq）。（123）I-IMPY的等效有效剂量和有效剂量分别为0.042 +/- 0.003 mSv / MBq和0。分别为035 +/- 0.001 mSv / MBq。（123）I-IMPY的平均有效剂量与（111）In-二亚乙基三胺五乙酸（0.035 mGy / MBq）的平均有效剂量相近，小于（111）In-pentetotide（0.81 mGy / MBq）的平均有效剂量的一半（123）I-IMP的两倍（0.018 mGy / MBq）。男女之间或AD患者与对照对象之间没有发现显着差异。结论（123）I-IMPY可能是一种安全的放射性示踪剂，具有适当的生物动力学，可以对AD患者的淀粉样蛋白斑进行成像。男女之间或AD患者与对照对象之间没有发现显着差异。结论（123）I-IMPY可能是一种安全的放射性示踪剂，具有适当的生物动力学，可以对AD患者的淀粉样蛋白斑进行成像。男女之间或AD患者与对照对象之间没有发现显着差异。结论（123）I-IMPY可能是一种安全的放射性示踪剂，具有适当的生物动力学，可以对AD患者的淀粉样蛋白斑进行成像。