A multislice whole body positron-emission transaxial tomograph (PETT IV) has been used to delineate the distribution of **1**1C-labeled palmitate in the myocardium of patients two days to five months following myocardial infarction. This approach is an extension of previous observations demonstrating diminished uptake of **1**1C-labeled fatty acids in isolated perfused rabbit hearts rendered ischemic for prolonged intervals and in regions of myocardial infarction in closed-chest dogs given intravenous injections of **1**1C-palmitate. 21 patients with myocardial infarction and 7 patients without infarction have been studied. Anterior, anteroseptal, and lateral infarcts are defined in the transverse sections. Sagittal and coronal sections identify inferior infarcts which cannot be seen in transverse images. Algorithms for measuring the extent of infarction by analysis of the reconstructed images are evaluated by comparing infarct size estimated tomographically to infarct size estimated enzymatically based on analysis of plasma MB CK time-activity curves.