The general direction of this investigation for the forthcoming year will consist essentially in the continuation of last year's effort. From the standpoint of instrumentation, PETT IV is presently installed in our Coronary Care Unit, where it is used for the in vivo assessment of mycardial integrity, and also in studies of the brain and liver. Another positron emission transverse tomograph, PETT V, has been constructed and will be utilized specifically for cerebral studies and for small animal work, particularly cerebral studies in rhesus monkeys. That instrument is characterized by a high resolution, up to 7 mm, and by very fast data acquisition capabilities, up to 1 second. Studies will be performed with isolated perfused rabbit hearts and rabbits in vivo to characterize myocardial fatty acid metabolism after administration of 11C-palmitate. Effects of physiological and biochemical factors such as altered blood flow will be quantified. Information acquired from experimental animal preparations will be used to facilitate interpretation of positron emission tomograms obtained after administration of 11C-palmitate to patients in studies designed to delineate and quantify the extent of ischemic myocardium and to identify regional alterations in metabolism. In chemistry work will continue in the synthesis of 7-fluoro-palmitic acid and carrier-free fluorinated aromatics. An alternative being investigated in the method of preparing aromatic fluorinated compounds is the synthesis of the appropriate triazines which on treatment with sulphonic acid give the desired diazonium compounds. Work with enkephalins will be continued with the labeled compounds studied in an animal model. The behavior will be compared to that of morphine prepared by methylation of normorphine. Neurological studies will be diredted to the measurement of flow, tissue pH, blood volume, and tissue hematocrit in quantitative studies in human subjects. In addition, we are planning to study in human subjects using the PETT V system rCMRGlu by means of 11C-glucose and oxygen metabolism by means of 150-oxygen.