[en] Although according to the literature S-methyl dithiocarbazate could not form complex directly with ^99mTcO₄^- in acidic condition, we deduced that the formation of such complex should be possible based on 'cavity model' and the knowledge of coordination chemistry, and that acidic condition would favor the process. This deduction had been verified by the preparation of lipophilic complex in strong acidic condition with a radio-chemical yield of 80-95%. The radioactive content accumulated in the myocardium of small white mice with ID%/g of 6.4 at 2 min p.i. and it was washed out gradually