Abstract: In developing 99Tc m-labelled dopamine transporter imaging agents, a new substituted compound is designed and synthesized. By tetering S 3 chelate system onto it, one technetium "3+1" complex is formed. Biodistribution studies are carried out in mice. The results demonstrate that the labeled compound(a) has the ability to penetrate the intergrate blood brain barrier(1.03 %/g), at 5 min, post injection and retains for a certain time in brain. The ST/CB is 1.3 at 60 min after iv injection in mice. It also shows that brain uptake and selectivity of labeled compound(a) are higher and further improving is needed.