论文部分内容阅读
一、引言 近年来~(125)Ⅰ用作示踪原子日益增多,特别是在放射免疫试验中用来标记抗原。为确定~(125)Ⅰ标记的抗原或其它~(125)Ⅰ标记物的比放射性,除用相对测量法外,还可用绝对测量法。 ~(125)Ⅰ的衰变方式为电子俘获,其中K层电子俘获占80％,L、M……层电子俘获占20％(图1)。电子被俘获后分别产生特征K-X射线(27.5千电子伏)、L-X射线等,后者能量太小对测量无贡献。核俘获电子后,生成激发态~(125)Te,在回到基态时释放35.5千电子伏的
I. INTRODUCTION In recent years, ~ (125) Ⅰ has been used as a tracer atom for increasing the number of antigens, especially in radioimmunoassay. In order to determine the specific radioactivity of ~ (125) I-labeled antigens or other ~ (125) I markers, in addition to using relative measures, absolute measures can also be used. The decay mode of ~ (125) Ⅰ is electron capture, in which K layer electron capture accounts for 80% and L, M ...... layer electron capture accounts for 20% (Fig.1). After the electrons were captured, they produced the characteristic K-X ray (27.5 keV), L-X ray and so on. The latter energy was too small to make any contribution to the measurement. Nuclear capture of electrons, the formation of excited state ~ (125) Te, released back to the ground state of 35.5 thousand electron volts