Investigations of Labeling Insulin-like Growth Factor-1 Aanalogue with ~(188)Re

Objective To establish a stable method for labeling insulin-like growth factor-1 analogue(IGF-1A) with 188Re.Methods The directly labeling method was adopted.Several labeling conditions were tested,such as the volume of Tween-80,the concentration of SnCl2·2H2O,the amount of IGF-1A,and the volume of 188Re perrhenate.The labeling efficiency was determined from 15 min to 8 h after labeling.The in vitro stability of 188Re-IGF-1A was analyzed by using human serum or sodium chloride as challenging agent,and the labeling efficiency was determined from 2 to 24 h after added challenging agent.Results The optimum labeling conditions were 10 μl 0.1% Tween-80,100 μl SnCl2·2H2O(10 mg/ml),50μl IGF-1A(2 mg/ml),and 50μl 188Re perrhenate,incubated 30 min at room temperature.The labeling efficiency of 188Re-IGF-1A could reach(94.07±0.32)% and the amount of radiocolloid was(5.50±1.50)%.It was(89.07±0.74)% after incubation for 6 h at room temperature,and was(76.57±9.96)% after incubation for 24 h with human serum.Conclusion This method of labeling IGF-1A with 188Re using SnCl2·2H2O is stable and high labeling efficiency can be obtained.