Abstract: MIBG (metaiodobenzylguanidine)is a functional analog of the neurotransmitter norepinephrine.It is trans-ported,stored and rel eased by a mechanism similar to that of norepinephrine.MIBG and its derivatives are useful radio-pharmaceutical for the clinical scintigraphy and treatment of neural crest tumors such as pheochromocytoma and neurob-lastoma.Also it is applicable for myocardial imaging in evaluating the integrity and function of my ocardial presynapse sympathetic neuron.