Abstract: COMPARISON OF BIODISTRIBUTION IN MICE AND PHARMACOKINETICS OF 99Tcm CQDO WITH 99Tcm CQDO MeBZhu Junqing\ Luo Shineng\ Wu Chunying\ Ji ShurenCao Guoxian\ Zhou Xiang\ Chen Zhengping\ Mo Yiqing (State Key Laboratory of Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063) Abstract\ 99Tcm CQDO and its adduct of methaneboronic acid 99Tcm CQDO MeB are prepared by the reduction of SnCl 2·2H 2O with Na 99 Tc mO 4. The radiochemical purity of 99Tcm CQDO and 99Tcm CQDO MeB are higher than 90%\ after being purified by extration. The biodistribution of 99Tcm CQDO and 99Tcm CQDO MeB in mice demonstrate that both of them can be easily absorbed by myocardium. 99Tcm CQDO shows rapid clearence in myocardial issue and its uptake is only (5.88±1.66)% ID/g in 10 min postinjection. However, 99Tcm CQDO MeB has longer retention in heart muscle and its uptake is (7.42±0.17)% ID/g in 60 min postinjection. The elimination of each from blood accords with a biexponential pattern. The first T 1/2 is 1.38 min and 1.51 min, respectively. The partition coefficient of 99Tcm CQDO and 99Tcm CQDO MeB are 25 and 12 respectively at pH7.40.Key words 99Tcm CQDO\ 99Tcm CQDO MeB\ pharmacokinetics\ biodistribution in mice