We studied the cardiac uptake of 2-14C-D-deoxyglucose (14C-DG) in 6 dogs subjected to a 15 min left anterior descending coronary artery (LAD) occlusion followed by 30 min reflow. Coronary arterial flows during occlusion were determined with 46Sc microspheres. After 30 min reflow, 50 microCi 14C-DG were given intravenously to determine cardiac uptake. The animal was killed 45 min later and 46Sc counts/min were determined in gamma and beta counters. Quenching was determined with non radioactive blood for both isotopes in the beta counter. Contribution of 46Sc counts/min to the 14C channel was subtracted. 14C uptake was in DPM/g and was higher in the cardiac ischemic regions of four of the six dogs. In three of the six animals there was an inverse curvilinear relation between 14C-DG cardiac uptake and occlusion flow. This observation was further confirmed by high resolution autoradiography, indicating that enhanced cardiac uptake of radiolabeled DG may be a useful positron emission tomographic marker for reversible myocardial ischemia.