Abstract: Tc mN CHPDTC(CHPDTC:N cycloheptyl dithiocarbamate dihydrate) is prepared through a two step ligand exchange reaction with SnCl 2·2H 2O as reduction agent and DTCZ(N methyl, S methyl dithiocarbazate) as a donor of nitride nitrogen atom (N 3- ). The radiochemical purity (RCP) of the product is over 90 % by TLC. It is stable over 7 h at room temperature. The lg D value is 1 50. The biodistribution results in mice indicate the complex has high myocardial uptake and good retention. The heart uptake (ID/(%·g -1 )) is 17 17, 16 82 and 19 18 at 5,30 and 60 min post injection. R (heart/blood), R (heart/lung) and R (heart/liver) are 7 10, 1 43 and 0 41 at 60 min post injection respectively. The results for the complex suggest that it will be potentially useful as a myocardial perfusion imaging agent.