TRANSAXIAL TOMOGRAPHIC IMAGING OF CANINE MYOCARDIUM WITH PALMITIC-C-11 ACID

Abstract

Radiopharmaceuticals incorporated directly into the metabolic pathways in myocardium provide a useful means for evaluating such processes. Palmitic acid, a major physiologic substrate of myocardium, has a well-understood role in myocardial metabolism. Accordingly, 11C-palmitic acid was the substrate chosen for use in conjunction with positron emission transaxial tomography to obtain images of dog myocardium. This procedure provided high-contrast images of transverse sections of the myocardium, with good target-to-nontarget ratios (in the image), over a period of 5-85 min. Clearance half-times for blood and myocardial tissue were 4.8 and 330 min, respectively. In normal myocardium, images obtained with 11C-palmitic acid were compared with those obtained with 13NH3 and 11CO-Hb. In vivo images of hearts with myocardial infarcts showed a clear delineation of infarcts and normal tissue.