99Tc^m-伊班膦酸的小鼠体内生物分布与兔骨显像研究

Mouse biodistribution and rabbit bone imaging of 99Tcm-Ibandronate

目的制备99Tcm-伊班膦酸(IBN)并初步评估其生物学性能,探讨其用于骨显像的可能性。方法采用亚锡还原法制备99Tcm-IBN,观察其体外稳定性及在小鼠体内的生物分布,与99Tcm-亚甲基二膦酸盐(MDP)比较进行家兔骨显像。采用两样本t检验分析数据。结果99Tcm-IBN的放化纯为(98.24±0.24)%,在室温下放置6h其放化纯仍大于95%。小鼠体内分布表明,99Tcm-IBN从血液和软组织清除迅速,主要经泌尿系统排泄,能被小鼠骨组织特异性摄取且摄取速度快,在注射后30min即达到峰值[(9.85±0.51)每克组织百分注射剂量率(%ID/g)],并能在骨组织中滞留较长时间;肝、脾摄取低,具有较高的骨/软组织比值。兔骨显像结果示,注射99Tcm-IBN后1h,本底基本清除,脊柱、肋骨和四肢骨显像均很清晰。与99Tcm-MDP相比,99Tcm-IBN骨摄取迅速且摄取量较高,软组织清除快,肝、脾摄取低;注射后各时间点(10、20、30、40、50min)99Tcm-IBN的骨与各软组织的比值均高于99Tcm-MDP(t值:2.867~5.426,均P<0.05)。注射后1~2h99Tcm-IBN的兔骨显像效果优于99Tcm-MDP。结论99Tcm-IBN具有良好的生物学性能,其显像效果与99Tcm-MDP相当,并可缩短注射后等待显像的时间,有望成为一种新的骨显像剂。

Objective To prepare 99Tcm-Ibandronate(IBN)and explore the feasibility of 99Tcm-IBN as a radiopharmaceutical for bone imaging.Methods 99Tcm-IBN was synthesized by the stannous reduction method.The biodistribution in mice was observed and the bone imaging was performed in rabbits.Two-sample t test were used to analyze the data.Results The 99Tcm-IBN was highly stable in vitro,with a radiochemical purity of(98.24±0.24)%.The radiochemical purity was still >95% after 6 h at room temperature.In vivo distribution experiments showed that 99Tcm-IBN could be specifically and rapidly incepted by bones of mice,and the peak value((9.85±0.51)percentage activity of injection dose per gram of tissue(%ID/g))was observed at 30 min post-injection.The radioactivity was retained in bone for a long time.The uptake by the liver and spleen was low,and the radioactivity was eliminated rapidly from the blood and soft tissues,demonstrating a high bone/soft tissue ratio of radioactivity.Rabbit bone imaging showed that the background was nearly eliminated and the images of the spinal column,costal bones,and extremity bones were very distinct at 1 h post-injection.Compared to 99Tcm-methylene diphosphonate(MDP),99Tcm-IBN was characterized by rapid and high uptake by bones,rapid elimination from soft tissues,and low uptake by the liver and spleen.The bone/soft tissue ratios of 99Tcm-IBN at each time point(10,20,30,40,50 min)were significantly higher than those of 99Tcm-MDP(t values:2.867-5.426,all P<0.05).The imaging performance of 99Tcm-IBN was superior to 99Tcm-MDP at 1-2 h post-injection.Conclusions 99Tcm-IBN has good biological properties.Its imaging performance is comparable to that of 99Tcm-MDP and has shorten imaging waiting time.It might be a promising new bone imaging agent.