Since the application of positron emission computed tomography (PET) for myocardium, the evaluation of myocardial blood flow, glucose metabolism, fatty acid metabolism, oxygen consumption and etc. has been performed. Especially, it has been regarded very important clinically to evaluate myocardial viability from the mismatch of myocardial glucose metabolism and blood flow. Many early myocardial PET studies were qualitative, while recently noninvasive quantitation method without arterial blood sampling has become possible in quantitating myocardial glucose metabolism or myocardial blood flow reserve. We quantitated regional myocardial glucose utilization rates (rMGU) in 114 cases during fasting, oral glucose loading, or insulin clamp to study the relation between rMGU and plasma insulin value or FFA value, the normal rMGU value during each condition and the difference of rMGU among each part of myocardium. And as to the question in which condition of FDG study was appropriate to evaluate myocardial viability, we introduced the opinion of Schelbert for oral glucose loading or insulin injection method and presented our opinion for fasting or mild insulin clamp.