Diaminedithiol (DADT) or N-monosubstituted DADT is known to form lipophilic neutral chelates with technetium. As a result, they are used for brain imaging agents. However, 99mTc-N,N'-dimethylDADT has been demonstrated to have a positive charge and a lower lipophilicity (log P = 0.1) in this experiment. The results of a biodistribution study showed that most activity was found in the intestine after 1 hr, which is the evidence of bile excretion. Increased heart-uptake in mice suggests that this compound or its derivatives can be used as a myocardial-imaging agent.