Aim/objectives/backgroundIodine-131-m-iodobenzylguanidine ([I-131]mIBG) is used worldwide for the diagnosis and therapy of neuroendocrine tumors, particularly adrenal medullae tumors. After the synthesis and preparation of a radioiodinated MIBG drug formulation, quality control testing to determine its radiochemical purity (RCP) should be performed. European Pharmacopoeia 8.0 requires that the quality control include a test for RCP for the determination of [I-131]mIBG. Previously reported procedures using reversed-phase conditions require long retention times. Our system enables the separation of [I-131]mIBG within a few minutes. The aim of this work was to carry out RCP testing for [I-131]mIBG without any type of sample pretreatment.MethodsRCP testing for [I-131]mIBG has been carried out using high-performance liquid chromatography and thin-layer chromatography methods.ResultsA simple and rapid reversed-phase isocratic system enables the HPLC investigation of RCP testing for [I-131]mIBG used for therapy within a few minutes.ConclusionsFrom the point of view of radiation protection, this method is safer, especially for therapeutic amounts of [I-131]mIBG.