Beyer G J, Offord R, Künzi G, Aleksandrova Y, Ravn U, Jahn S, Barker J, Tengblad O, Lindroos M
Cantonal Hospital, University of Geneva, Div. Nuclear Medicine, Switzerland.
Nucl Med Biol. 1997 Jul;24(5):367-72. doi: 10.1016/s0969-8051(97)00011-5.
High-resolution gamma spectroscopy was applied to measure simultaneously the biodistribution of carrier-free radionuclides of several lanthanides (141Ce, 145Sm, 149Gd, 167Tm) and 225Ac in tumor-bearing nude mice. Mixtures of the radiotracers were injected in solutions containing different concentrations of EDTMP (ethylenediaminetetramethylenephosphonic acid). The strong dependence of liver uptake on the ionic radius of the radio-lanthanides was confirmed for all tracers used. The ratios of radioactivity concentrated in tumour that concentrated in liver are strongly influenced by the EDTMP concentration, reaching values close to 10 for Tm, 3 for Sm, and 1 for Ac. The optimal EDTMP concentrations, giving highest tumor-to-liver ratios of enrichment, were between 1 and 10 mM for 100 microL injected volume for the animal model used in this experiment. In radionuclide therapy using EDTMP as ligands, close control of ligand concentration will be necessary.
应用高分辨率γ能谱法同时测量了几种镧系元素（141Ce、145Sm、149Gd、167Tm）的无载体放射性核素以及225Ac在荷瘤裸鼠体内的生物分布。将放射性示踪剂混合物注入含有不同浓度EDTMP（乙二胺四亚甲基膦酸）的溶液中。对于所有使用的示踪剂，均证实肝脏摄取对放射性镧系元素的离子半径有强烈依赖性。肿瘤中浓聚的放射性与肝脏中浓聚的放射性之比受EDTMP浓度的强烈影响，Tm的该比值接近10，Sm为3，Ac为1。对于本实验中使用的动物模型，当注射体积为100微升时，使肿瘤与肝脏富集比最高的最佳EDTMP浓度在1至10 mM之间。在使用EDTMP作为配体的放射性核素治疗中，有必要严格控制配体浓度。
