? Myocardial perfusion imaging in normal and acute myocardial infarction（AMI） model dogs with 99m Tc-Teboroxime was reported The experiment in normal dogs showed that 99m Tc-Teboroxime has a high extraction fraction and rapid myocardial washout After injection the myocardium uptaked immediately The heart/liver activity ratio is 436 The myocardial activity decreased to half of its peak value at 612min The lung uptake is less The heart/lung activity ratio is 212 at 1 min and 20 at 2 min respectively The ischemic myocardium in AMI models uptaked 99m Tc-Teboroxime less and washout slower The peak value in ischemic area only reached 06 of normal myocardium The myocardium acticity at 612min was 086 times that of the peak value Finally the defects were seen clearly in the two myocardial infarction canine models with a rapid planar imaging