131I-β-CIT多巴胺转运蛋白显像的基础研究

用过氧乙酸法进行 1 31 I标记 β- CIT。以 MPTP连续 5 d注入猫股静脉内 ,建立 PD模型。取正常猫 6只、PD模型猫 3只 ,每只分别注入 74 MBq/ 0 .5 ml　 1 31 I- β- CIT,观察 4 h和 2 0 h时动物体内分布情况。将 74 MBq/0 .5 ml/只 1 31 I- β- CIT经股静脉分别注入正常组及 PD组猫体内 ,于注射后 0 .5、1、2、4、2 0 h进行脑显像 ,计算纹状体 1 31 I-β- CIT的特异性结合。结果显示 :标记物 1 31 I-β- CIT放化纯达 97.6 2 %± 0 .31%。室温下放置 4 h以及分别与水、人新鲜血清孵育 4 h后 ,放化纯平均值分别为 95 .33%± 0 .5 9%、95 .14 %± 0 .87%、95 .0 6 %± 0 .6 4 %。猫静脉注射 1 31 I- β- CIT后 ,放射性主要浓聚于纹状体区 ,其次为肺、肝、肾。以每克组织中放射性占总放射性计数的百分比计算 ,正常猫 4 h和 2 0 h纹状体 /小脑比值分别为 18.31± 3.5 0和 2 0 .5 1± 2 .2 3。 2 0 h PD猫纹状体 /小脑的比值为 11.2 0± 0 .2 9,与 2 0 h正常猫相比显著下降 (P<0 .0 5 )。显像研究显示正常猫纹状体 2 0 h特异性结合为 4 .83± 0 .82 ,PD模型猫为 2 .92± 0 .6 6 ,两者有显著性差异 (P<0 .0 5 )。分布研究与显像研究的结果相符。因此 ,β- CIT是一种较理想的 DAT配体 ,碘标 β- CIT的 DAT功能显

Basic Study of Dopamine Transporter Imaging with 131I-β-CIT

beta-CIT was labeled with 131I by the peracetic acid method. Cat model of Parkinsonism was set up with MPTP. Each of normal and PD model cats was given an injection of 74 MBq/0.5 ml 131I-beta-CIT into the femur vein. Then the blood samples were obtained at 4 h and 20 h, the radioactivity was counted with calibrator. The biodistribution data of 131I-beta-CIT in cat body was calculated (ID%/g). The cats were subjected to imaging at 0.5 h, 1 h, 2 h, 4 h, 20 h after the administration of radiopharmaceutical. The radioactivity in striatum and cerebellum was measured and striatal specific binding ratios were calculated. The Results showed that the radio chemical purity of 131I-beta-CIT was 97.62% +/- 0.31%. The 131I-beta-CIT remained stable for at least 4 h after incubation with water and serum respectively. Following intravenous administration in cats, 131I-beta-CIT showed high accumulation in striatum. The study of imaging in cats showed that striatal specific uptake of 131I-beta-CIT at 20 h after injection was 4.83 +/- 0.82 in normal cats and 2.92 +/- 0.66 in PD cats. There was a significant reduction of striatal tracer uptake in PD cats, compared to the controls. The results of biodistribution study was in agreement with the results of imaging study. These results suggest that beta-CIT is an ideal agent for dopamine transporter imaging and can be used for the diagnosis of Parkinson's disease.