Abstract: Optimized geometries of nine 99 Tc m Q complexes are obtained using simulated annealing method and monte carlo method of molecular dynamics. Then the structures of these complexes are optimized by molecular mechanics, and further optimized by semi empirical quantum mechanics method--ZINDO/1 and the electronic structures are calculated. The result reveales that there is a curve correlation between the heart uptake and the dipole moment and the acme of the curve may be inferably in the range from 7 to 9, and that heart uptake has some relationship with E LUMO .