Molecular imaging has been focused in the field of cardiovascular medicine. With use of suitable radiopharmaceuticals, neuronal function in the cardiovascular system has been assessed in vivo. Of particular, positron emission tomography(PET) plays an important role for in vivo quantification of various neurotransmitter and receptor functions. We have recently developed 11C-labeled CGP12177, hydrophilic beta-adrenoreceptor antagonist, to measure myocardial beta-receptor density(Bmax) in vivo. The basic study showed high uptake in the lung and myocardium which was significantly suppressed by propranolol pretreatment in the rat model, suggesting specific binding of this ligand in the beta-receptors. Bmax was significantly reduced in patients with congestive heart failure. In addition, Bmax was inversely correlated with washout rate of 123I-MIBG from the myocardium in these patients. These new imaging technique has a potential role for assessing severity of heart failure and providing appropriate treatment strategy.