Myocardial perfusion imaging with 99mTc-DMPE in man

Technetium-99m DMPE (99mTc-DMPE) is a newly synthesized myocardial perfusion imaging agent that shows intense myocardial accumulation in the dog. In the present study, dosimetry and potential clinical usefulness of this agent were assessed in four human subjects. Absorbed radiation doses were low, with the highest doses consisting of 200 mrad/mCi (54 microGy/MBq) to the gallbladder and 160 mrad/mCi (43 microGy/MBq) to the liver. No evidence of clinical toxicity was found. Technetium-99m DMPE did image the myocardium, but the ratio of target to nontarget activity was less favorable than that observed in the dog. Intense hepatic 99mTc-DMPE activity interfered with clinical imaging of the cardiac apex in two of the four subjects. We conclude that the prototype radiopharmaceutical, 99mTc-DMPE, is capable of myocardial perfusion imaging in man but the planar myocardial images produced are of inferior quality compared with 201Tl myocardial images. Further work is justified to develop related compounds to overcome the clinical limitations described.