Kumar Vijay, Kumar Divesh, Howman-Giles Robert B, Little David G
Department of Nuclear Medicine, Westmead Hospital, NSW 2145, Australia.
Nucl Med Commun. 2007 Feb;28(2):101-7. doi: 10.1097/MNM.0b013e328013eb74.
To evaluate the potential of (99m)Tc-pamidronate ((99m)Tc-APD) against (99m)Tc-medronate ((99m)Tc-MDP) as a new bone-seeking agent using intact bone and fractured femur in a rat model.
(99m)Tc-APD was prepared by the stannous reduction method. Scintigraphic images were obtained at 2 h and 24 h after intravenous injection of (99m)Tc-APD or (99m)Tc-MDP in rats, then they were culled to estimate activities in various organs. Bone uptake (as percent injected dose/gram weight) was estimated in an intact femur and in 1 week post-fracture model. The urinary excretion dose (as percent injected dose) was also estimated.
The bone uptake of (99m)Tc-APD was significantly higher (P<0.05) than (99m)Tc-MDP at 2 h and 24 h post-injection studies. (99m)Tc-APD uptake was further increased (P<0.05) in the fracture model than the intact femur. (99m)Tc-APD uptake in the soft tissues including liver and the kidneys was lower than (99m)Tc-MDP. Renal excretion was faster and the ratios of bone to blood and bone to soft tissues were higher with APD than MDP. APD dose was selected at 1% of MDP, to obviate therapeutic effect, as the former compound is 100 times more potent than MDP.
Our results suggest that (99m)Tc-APD uptake by intact bone and fractured bone was significantly higher than (99m)Tc-MDP. The renal clearance of (99m)Tc-APD was faster and soft tissue uptake was lower than (99m)Tc-MDP. These results suggest that APD has the potential to become an excellent bone-imaging agent.
在大鼠模型中，使用完整骨骼和股骨骨折模型，评估（99m）锝-帕米膦酸盐（（99m）Tc-APD）作为一种新型骨显像剂相对于（99m）锝-亚甲基二膦酸盐（（99m）Tc-MDP）的潜力。
采用亚锡还原法制备（99m）Tc-APD。在大鼠静脉注射（99m）Tc-APD或（99m）Tc-MDP后2小时和24小时获取骨闪烁显像图像，然后处死大鼠以评估各器官中的活性。在完整股骨和骨折后1周模型中估计骨摄取（以注射剂量的百分比/克重量表示）。还估计了尿排泄剂量（以注射剂量的百分比表示）。
在注射后2小时和24小时的研究中，（99m）Tc-APD的骨摄取显著高于（99m）Tc-MDP（P<0.05）。与完整股骨相比，骨折模型中（99m）Tc-APD的摄取进一步增加（P<0.05）。包括肝脏和肾脏在内的软组织中（99m）Tc-APD的摄取低于（99m）Tc-MDP。APD的肾脏排泄更快，且与MDP相比，其骨与血以及骨与软组织的比率更高。由于前者化合物的效力比MDP高100倍，为避免治疗效果，选择APD的剂量为MDP的1%。
我们的结果表明，完整骨骼和骨折骨骼对（99m）Tc-APD的摄取显著高于（99m）Tc-MDP。（99m）Tc-APD的肾脏清除更快，软组织摄取低于（99m）Tc-MDP。这些结果表明APD有潜力成为一种优秀的骨显像剂。
