^188Re-RGD-4CK的制备及其示踪动力学研究

目的：探讨^188Re标记RGD-4CK的方法及其在健康家兔体内的示踪动力学特性。方法：采用预锡化法^188Re直接标记RGD-4CK，纸层析测定标记多肽的标记率并计算比活度。测定9只家兔经耳缘静脉注射37MBq^188Re-RGD-4CK后不同时相点血液中的放射性浓度，采用DAS软件评价标记多肽示踪动力学行为，以F值检验、AIC值、R2值并结合αvβ3受体在正常机体表达实际，对血液放射性浓度一时间数据进行房室模型曲线拟合，根据拟合结果计算示踪动力学参数。结果：^188Re-RGD-4CK的标记率大于97％，比活度为3．97±0．02TBq／mmol。^188Re-RGD-4CK在健康家兔体内的放射浓度实测值符合以1／C2为权重系数拟合的二室模型理论计算值。结论：预锡化法^188Re直接标记RGD-4CK制备方法简便，标记率高，无需分离纯化。^188Re-RGD-4CK在健康家兔体内的示踪动力学符合以1／C2为权重系数拟合的二室模型。

Study on the Preparation of ^188Re-RGD-4CK and Its Tracer Kinetics

Objective： To explore the method of RGD-4CK radiolabeled with ^188Re and its tracer kinetic features in normal rabbits. Methods： RGD-4CK was directly labeled with ^188Re by the method of pretinning. Labeling efficiency was measured by paper chromatography and then specific activity was calculated. Radioactive concentration of ^188Re-RGD-4CK at different sampling times was measured after intravenous rejection through ear-edge vein with 37MBq ^188Re-RGD-4CK into 9 rabbits. Tracer parameters were evaluated with DAS software. Radioactive concentration-time data was fitted with compartmental models based on F test, AIC value, R2 value and the expression status of alpha（v ）beta（3 ） receptor in normal organisms. Tracer kinetic parameters were then calculated according to the fitting results. Results： Labeling efficiency of ^188Re-RGD-4CK was higher than 97%. Its specific activity was 3.97 ± 0.02 TBq/mmol. Radioactive concentration-time curve of ^188Re-RGD-4CK can be fitted with a two-compartment model with a weight coefficient of 1/C2. Conclusions： The preparation of ^188Re-RGD-4CK with a method of pretinning was simple and convenient and its labeling efficiency was significantly high. Labeling product can be used directly without separation and purification. Tracer kinetic features in normal rabbits was fitted much better by a two-compartment model with a weight coefficient of 1/C2.