Effect of coronary blood flow on uptake and washout of /sup 99m/Tc DMPE and /sup 201/Tl

After intravenous administration of /sup 99m/Tc DMPE the flow-dependent kinetics were studied in dogs during induced ischemia and during induced maximal reactive hyperemia. A control group was also studied. Mean time-activity curves obtained from the myocardial wall were compared within the same intervention group and also with other groups. During reactive hyperemia, there was a rapid and absolute increase in uptake followed by a rapid washout, whereas during ischemia there was a slow and decreased uptake followed by a slow washout. The magnitude of /sup 99m/Tc DMPE uptake during reactive hyperemia was slightly less than that of /sup 201/Tl, but the decreased uptake with ischemia was about equal for the two agents. Following maximal uptake in the myocardium the effective half-life of /sup 99m/Tc DMPE was one-third to one-fourth that of /sup 201/Tl. The similar kinetics of /sup 99m/Tc DMPE compared to /sup 201/Tl suggests its usefulness in the evaluation of ischemic heart disease.