Dewanjee M K, Hnatowich D J, Beh R
J Nucl Med. 1976 Nov;17(11):1003-7.
The present skeletal-imaging agents labeled with radiogallium rely upon carrier gallium to augment bone uptake; no gallium-labeled bone-imaging agent free of this disadvantage is available. In attempts to develop such agents, we prepared 68Ga-ethylenediaminetetramethylene phosphonate (68Gs-EDTMP) and 68Ga-diethylenetriaminepentamethylene phosphonate (68Ga-DTPMP) and determined their biologic distributions in rats and dogs. These compounds combine the bone-seeking characteristics of phosphonic acid and the complexing ability of EDTA and DTPA analogs. The chelates are administered without gallium carrier. In rats, 50-60% of the carrier-free dose accumulates in bone at 1 hr after intravenous injection, while 25--30% is excreted through the urine. In dogs, at 3 hr after intravenous injection 35% is found in bone. Although the general patterns of organ distribution of the two 68Ga chelates are similar, 68Ga-EDTMP appears superior because of its faster blood clearance. Bone images obtained with this compound in dogs, using a multidetector positron camera, are presented. The optimum time for imaging was found to be 2.5--3 hr after injection.
目前，放射性镓标记的骨骼显像剂依赖载体镓来增加骨摄取；尚无不含此缺点的镓标记骨显像剂。为研发此类显像剂，我们制备了68Ga-乙二胺四亚甲基膦酸酯（68Ga-EDTMP）和68Ga-二亚乙基三胺五亚甲基膦酸酯（68Ga-DTPMP），并测定了它们在大鼠和犬体内的生物分布。这些化合物兼具膦酸的亲骨特性以及EDTA和DTPA类似物的络合能力。螯合物在无镓载体的情况下给药。在大鼠中，静脉注射后1小时，50%-60%的无载体剂量积聚在骨骼中，而25%-30%通过尿液排出。在犬中，静脉注射后3小时，35%分布于骨骼中。尽管两种68Ga螯合物的器官分布总体模式相似，但68Ga-EDTMP因其血液清除速度更快而显得更具优势。本文展示了使用多探测器正电子相机在犬体内用该化合物获得的骨图像。发现最佳成像时间为注射后2.5-3小时。
