Abstract: THE PREPARATION AND BIODISTRIBUTION OF A NEW 99TcmNITRIDO COMPLEX 99TcmNMIBIZhang Xianzhong\ Wang Xuebin\ Zhang Junbo (Department of Chemistry, Beijing Normal University, 100875)ABSTRACTThe technetium99m nitrido intermediate is synthesized by using SnCl2·2H2O as reductant, and the complex 99TcmNMIBI is obtained through ligandexchange reaction. The labelling yield of 99TcmNMIBI is over 95％ by TLC. The conditions of preparing 99TcmNMIBI are optimized. Results of stability and partition coefficient of 99TcmNMIBI indicate that the complex is lipophilic and stable over 10 h at room temperature. The biodistribution of 99TcmNMIBI in mice shows high myocardium uptake, and rather rapid clearance. For 5min postinjection the hearttoblood, hearttolung and hearttoliver ratios are 3.18, 1.72 and 1.42， respectively. The new complex may be suitable for instant myocardial imaging. 99TcmNMIBI has significant different biodistribution characteristics from 99TcmMIBI. Based on these promising properties, 99TcmNMIBI should be a new potential myocardial perfusion imaging agent.Key words myocardial perfusion imaging agent 99TcmN core radiopharmaceutical biodistribution 99TcmNMIBI