新型心肌灌注显像剂 99 Tc m N DBODC5在兔体内的生物分布

Study of biodistribution properties of a new myocardial imaging agent 99mTc(N)(PNP5)(DBODC)+

  • 摘要: 制备了 99 Tc m NN BODC5,并将其经静脉注射到新西兰白兔体内,进行活体显像,检测其活体生物分布及离体器官分布,研究 99 Tc m N DBODC5作为心肌灌注显像剂的可行性。活体生物分布结果显示, 99 Tc m N DBODC5的心肌摄取迅速,心肌摄取量低于 99 Tc m MIBI,  99 Tc m N DBODC5的肝清除速度显著快于 99 Tc m MIBI,在注射后 30 min时心与肝的 T/NT为 0.98± 0.52,已接近 1,显著高于 99 Tc m MIBI的心与肝的 T/NT(0.56± 0.19), P= 0.007。 60 min时, 99 Tc m N DBODC5的心与肝的 T/NT达到高峰 ,为 1.18± 0.57,而 99 Tc m MIBI仅为 0.71± 0.29。在 180 min内, 99 Tc m N DBODC5的心与肝的 T/NT维持在较高水平。 99 Tc m N DBODC5的肺摄取低,清除快,心与肺的 T/NT在 180 min内保持在 1.43± 0.37以上,与 99 Tc m MIBI无显著差别。 99 Tc m N DBODC5的肝清除迅速,避免了肝内放射性对左室下壁的干扰,有利于实现早期显像。故 99 Tc m N DBODC有望成为一种生物分布特性较好的新的心肌灌注显像剂。

     

    Abstract: 99TcmNDBODC5 for intravenous injection was prepared. The labelling yield was 95.0%±0.52%. Sixteen New Zealand rabbits were involved and planar gamma imaging was performed at 10 timepoint after injection of 99TcmNDBODC5. The radioactivity channes of organs were calculated by regions of interest (ROI) analysis. The 16 rabbits were divided into 4 groups and were sacrificed at 30, 60, 120, and 180 min after injection respectively. The activity for all excised organs were measured by γwell counting for calculating radiouptake. Myocardial uptake for 99TcmNDBODC5 is high. Though myocardial uptake was lower than 99TcmMIBI, the liver clearance for 99TcmNDBODC5 was more rapid than that of 99TcmMIBI. As early as 30 min after injection, 99TcmNDBODC5 hearttoliver ratio is 0.98±0.52 versus 0.56±0.19 for 99TcmMIBI (P<0.01). At 60 min postinjection, 99TcmNDBODC5 hearttoliver ratio improved to the peak value (1.18±0.57), compared with 0.71±0.29 for 99TcmMIBI, P<0.01. After 60 min, the hearttoliver ratio of 99TcmNDBODC5 was keeping at a high level until 180 min. 99TcmNDBODC5 exhibited rapid lung clearance, similar to that of 99TcmMIBI. The biodistribution in the isolated organs demonstrated the same trend. The rapid 99TcmNDBODC5 liver clearance may allow the earlier imaging, and overcome the photon scatter from the liver with high activity which interfered the inferoapical wall in myocardial images. 99TcmNDBODC5 is a promising new myocardial perfusion imaging agent with superior biodistribution properties.

     

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