A comparison of the technetium-labeled myocardial agents DiArs and DMPE to 201Tl in experimental animals

The biodistribution, kinetics, imaging characteristics and blood flow correlations of 99mTc labeled DiArs and DMPE were studied. The mice biodistribution were compared to 201Tl in mice and dogs, respectively. The myocardial kinetics of these agents were evaluated in normal and ischemic myocardium using miniaturized endocardial detectors. DiArs had a lower myocardial concentration (9.4 +/- 0.8% dose/g at 1 min), than DMPE (11.7 +/- 1.1% dose/g at 1 min) but both were considerably less than 201Tl (23-26% dose/g at 1 min). The kinetic characteristic of both technetium labeled agents suggested that redistribution into ischemic myocardium would not take place, since the clearance rate from normal and ischemic myocardium was similar for both the DiArs and DMPE . The clear visualization of the canine myocardium after i.v. injection demonstrated the superiority of DMPE over DiArs and the potential use of these agents, if proven, to behave the same in human trials.