EANM procedure guidelines for 131I-meta-iodobenzylguanidine (131I-mIBG) therapy

Meta-iodobenzylguanidine, or Iobenguane, is an aralkylguanidine resulting from the combination of the benzyl group of bretylium and the guanidine group of guanethidine (an adrenergic neurone blocker). It is a noradrenaline (norepinephrine) analogue and so-called false neurotransmitter. This radiopharmaceutical, labeled with I-131, could be used as a radiotherapeutic metabolic agent in neuroectodermal tumours, that are derived from the primitive neural crest which develops to form the sympathetic nervous system. The neuroendocrine system is derived from a family of cells originating in the neural crest, characterized by an ability to incorporate amine precursors with subsequent decarboxylation. The purpose of this guideline is to assist nuclear medicine practitioners to evaluate patients who might be candidates for I-131-meta-iodobenzylguanidine to treat neuro-ectodermal tumours, to provide information for performing this treatment and to understand and evaluate the consequences of therapy.