Abstract: SYNTHESIS, 125I LABELING AND BIODISTRIBUTION OF BIVALENT ANALOGS OF PRACTOLOL Cao Guoxian Li Weiyi Zhang Rongjun Yu Huixin Huang Xuquan(Jiangsu Institute of Nuclear Medicine, State Key Laboratory of Nuclear Medicine, Wuxi 214063)ABSTRACT The studies on synthesis and biodistribution of 125I labeled bivalent analogs of practolol as receptorsitedirected myocardial imaging agent is reported. The result indicates that the affinity of bivalent ligand to β receptor is over 50 times more than that of the monovalent ligand, and the ratio of hearttoblood is steadily increased and reaches the peak at 4 h after administration. Therefore it would be a potential myocardial imaging agent.Key words myocardial imaging agent bivalent analogs of practolol synthesis 125I labeling biodistribution