Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1 Naka-cho, Itabashi-ku, Tokyo 173-0022, Japan.
Nucl Med Biol. 2011 Apr;38(3):443-8. doi: 10.1016/j.nucmedbio.2010.09.007. Epub 2010 Dec 3.
4-[(11)C]Methylphenyl 2,4-diazabicyclo[3.2.2]nonane-2-carboxylate ([(11)C]CHIBA-1001) is a newly developed positron emission tomography (PET) ligand for mapping α(7) nicotinic acetylcholine receptors. We investigated whole-body biodistribution and radiation dosimetry of [(11)C]CHIBA-1001 in humans and compared the results with those obtained in mice.
Dynamic whole-body PET was carried out for three human subjects after administering a bolus injection of [(11)C]CHIBA-1001. Emission scans were collected in two-dimensional mode over five bed positions. Regions of interest were placed over 12 organs. Radiation dosimetry was estimated from the residence times of these source organs using the OLINDA program. Biodistribution data from mice were also used for the prediction of radiation dosimetry in humans, and results with and those without accommodation of different proportions of organ-to-total-body mass were compared with the results from the human PET study.
In humans, the highest accumulation was observed in the liver, whereas in mice, the highest accumulation was observed in the urinary bladder. The estimated effective dose from the human PET study was 6.9 μSv/MBq, and that from mice was much underestimated.
Effective dose estimates for [(11)C]CHIBA-1001 were compatible with those associated with other common nuclear medicine tests. Absorption doses among several organs were considerably different between the human and mouse studies. Human dosimetry studies for the investigation of radiation safety are desirable as one of the first clinical trials of new PET probes before their application in subsequent clinical investigations.
4-[(11)C]甲基苯基 2,4-二氮杂双环[3.2.2]壬烷-2-羧酸酯（[(11)C]CHIBA-1001）是一种新开发的正电子发射断层扫描（PET）配体，用于绘制α(7)烟碱型乙酰胆碱受体图谱。我们研究了 [(11)C]CHIBA-1001 在人体内的全身生物分布和辐射剂量，并将结果与在小鼠中获得的结果进行了比较。
对三名人体受试者给予 [(11)C]CHIBA-1001 静脉推注后，进行了全身动态 PET 扫描。采用二维模式在五个床位位置采集发射扫描。将感兴趣区域放置在 12 个器官上。使用 OLINDA 程序，从这些源器官的滞留时间估计辐射剂量。还使用小鼠的生物分布数据来预测人体的辐射剂量，并将考虑和不考虑器官与全身质量不同比例的结果与人体 PET 研究的结果进行比较。
在人体中，肝脏的积累最高，而在小鼠中，膀胱的积累最高。人体 PET 研究的估计有效剂量为 6.9 μSv/MBq，而小鼠的估计值大大低估了。
[(11)C]CHIBA-1001 的有效剂量估计值与其他常见核医学测试相关联。在人体和小鼠研究中，几个器官的吸收剂量有很大差异。在新的 PET 探针应用于后续临床研究之前，作为新的 PET 探针首次临床试验之一，对其进行辐射安全性的人体剂量学研究是可取的。
