放射性碘化IBZM对狗脑的SPECT显像研究

SPECT Imaging of Dog Brain by Using Radio iodinated IBZM

利用放射性碘化ＩＢＺＭ ｛左旋－２－羟基－３－碘－６－甲氧基－Ｎ－ ［ （１－乙基－２－吡咯烷基） 甲基］ 苯甲酰胺｝ 和断层显像技术，进行大鼠生物分布和狗脑多巴胺Ｄ２ 受体显像研究，了解放射性碘化ＩＢＺＭ 脑多巴胺Ｄ２ 受体显像的组织分布特性及其受体的选择性， 以及放射性分布与脑血流灌注显像的差异，并了解受体显像的最佳时期。利用低浓度过氧化氢乙酸法制备放射性碘化ＩＢＺＭ，并进行大鼠体内的分布研究。同时，利用狗进行放射性碘化ＩＢＺＭ 及其与Ｈａｌｏｐｅｒｉｄｏｌ竞争性抑制显像的对比研究， 进行放射性碘化ＩＢＺＭ 和９９ｍ Ｔｃ－ＥＣＤ脑血流显像的对比研究， 以及延期显像研究。结果表明：放射性碘化ＩＢＺＭ 能选择性地显示多巴胺Ｄ２ 受体富集的纹状体等脑组织， 纹状体部位的放射性摄取可被Ｈａｌｏｐｅｒｉｄｏｌ竞争性抑制， 表现为纹状体部位的放射性洗脱加快， 并且， 其放射性分布与脑血流灌注显像有明显的差异。在注射显像剂后１～３ ｈ， 显像效果较佳。认为放射性碘化ＩＢＺＭ 是一种特异性的脑多巴胺Ｄ２ 受体显像剂， 在注射显像剂后１～３ ｈ可进行ＳＰＥＣＴ断层显像。

By using SPECT and radio iodinated IBZM prepared by means of low concentraction peroxide hydrogen plus acetic acid, the dopamine D2 receptor imaging and its bio distribution were studied in dog brain and rats respectively to understand the tissue distribution characteristics and receptor selectivity of radio iodinated IBZM and to select the optimal time of requisition for the imaging. The comparative studies on receptor imaging of radio iodinated IBZM and its competitive inhibition by haloperidol, and the receptor imaging of radio iodinated IBZM and brain perfusion imaging of 99m Tc ECD, were carried out in dog brain respectively. The delayed imaging of radio iodinated IBZM was studied too. Results showed that radio iodinated IBZM could selectively visualize the tissues such as striatum in which there were a lot of dopamine D 2 receptors. The radio intake in striatum could be competitively inhibited by haloperidol, presenting the accelerated washout of radio iodinated IBZM. There was a significant imaging difference between radio iodinated IBZM and 99m Tc ECD. The optimal time of requisition for imaging was at 1~3 h post injection of imaging agent. It was suggested that the radio iodinated IBZM is a specific imaging agent for brain dopamine D2 receptor, the requisition for SPECT can be carried out 1~3 h after injection of imaging agent.