Abstract: Tc mN CHDTC(CHDTC:N cyclohexyl dithiocarbamate dihydrate) is prepared through a two step ligand exchange reaction by using SnCl 2·2H 2O as reduction agent and SDH(succinic dihydrazide) as a donor of nitride nitrogen atom (N 3- ) at room temperature. The radiochemical purity (RCP) of the product is over 90% by TLC. The biodistribution results in mice indicate that 99 Tc mN CHDTC has good brain uptake and retention, suggesting that it will be a new potential brain perfusion imaging agent. 99 Tc mN CHDTC also exhibits high myocardial uptake, but the R (heart/liver) is low thereby restricting the use of the complex as a good myocardial perfusion imaging agent. The ligand CHDTC is also labelled with 99 Tc mO 4 - directly by using FSA (formamidine sulfinic acid) as reduction agent. The biodistribution results in mice suggest 99 Tc m CHDTC is mostly accumulated in liver, whereas the heart and brain uptake is very low. This fact proves that the introduction of the 99 Tc m≡N 2+ core into the molecular structure of a radiopharmaceutical may obviously alter its biological behavior.