^(125)I-β-CIT动物体内生物学分布研究

^(125)I-β-CIT Biodistribution Study in animals

了解多巴胺转运体显像剂^（１２５）Ｉ－β－ＣＩＴ在体内的生物学分布情况，为其临床应用提供客观依据。采用Ｉｏｄｏｇｅｎ标记法制备 ^（１２５）Ｉ－β－ＣＩＴ，用ＨＰＬＣ进行分离纯化与鉴定，体内生物学分布用ＮＩＨ小鼠，脑放射性自显影用ＳＤ大鼠。结果表明；^（１２５）Ｉ－β－ＣＩＴ标记率为８４％，放化纯度大于９８％；ＮＩＨ小鼠血液清除，１２ｈ内符合二室模型（α＝３．８７，β＝０．１６２；Ｔ_（１／２α）＝０．１７９；Ｔ_（１／２β）＝４．２７６）；２４ｈ为三室模型（Ｐｉ＝５．２８，α＝０．４０３，β＝０．０４０，Ｔ_（１／２Ｐｉ）＝０．１３１，Ｔ_（１／２α）＝１．７１９，Ｔ_（１／２β）＝１７．２９８）；脑内摄取注射后１ｈ达高峰（９．１％± １．０％），关键器官肝、肺、脾、肾也具有较高的摄取［（９．８８±１．４３）－（１６．２９±１．７２）］，除肝外，其它器官均显示了较快的清除（Ｔ_（１／２）＜４ｈ；甲状腺摄取低，提示标记物体内稳定。ＳＤ大鼠放射性自显影显示；纹状体摄取好，纹状体／大脑皮质比值在注射后２０ｈ达高峰。说明^（１２５）Ｉ－β－ＣＩＴ在体内具有较好的稳定性和高的纹状体摄取率，可得到较高质量的ＳＰＥＣＴ图像，最佳采?

The purpose of this artical is to study the preparation and biodistribution in animal of dopamine transporter imaging agent ^(125)I- β-CIT. β-CIT was ^(125)I radioiodinated with odogen method, the dynamic distribution of ^(125)I-β-CIT in brain and critical organs were studied with SD rat (atuoradiography) and NIH mice respectively. The radiolabelling yield of ^(125)I-β-CIT was 84%, the radiochemical purity was better than 98%. Blood clearance could be explained by two-compartment model with a duration of 12h, (α = 3.87, T_(1/2α) =0.179, β =0.162, T_(1/2β) =4.276) and three-compartment model in 24h, (Pi= 5.28, T_(1/2Pi)= 0.131, α = 0.403, T_(1/2α). = 1.719, β= 0.040, T_(1/2β) = 17.298). The maxim uptake rate of brain (9.1% ± 1.0%) was reaches at lh, while at 24h, the target/noise ratio was higher. Critical organs liver, lung, spleen and kidney had high uptake rate [(9.881 1.43)- (16.29± 1.72)], except liver, other organs showed quick clearance (T_(1/2)<4h). Thyroid had a low uptake. Autoradiography of the brain showed that striatum uptake was good, striatum /cerebral cortex radioactivity ratio achieved maximum at 20h. The results show that ^(125)-β-CIT has a high striatum uptake and good stability in vivo, can provide good SPECT forages, the best acquisition time of SPECT may be about 20h after i.v..