Renal excretion of iodine-131 labelled meta-iodobenzylguanidine and metabolites after therapeutic doses in patients suffering from different neural crest-derived tumours

Eur J Nucl Med. 1997 May;24(5):544-52. doi: 10.1007/BF01267687.


Iodine-131 labelled meta-iodobenzylguanidine ([131I]MIBG) is used for diagnostic scintigraphy and radionuclide therapy of neural crest-derived tumours. After administration of therapeutic doses of [131I]MIBG (3.1-7.5 GBq) to 17 patients (n=32 courses), aged 2-73 years, 56%+/-10%, 73%+/-11%, 80%+/-10% and 83%+/-10% of the dose was cumulatively excreted as total radioactivity in urine at t=24 h, 48 h, 72 h and 96 h, respectively. Except for two adult patients, who showed excretion of 14%-18% of [131I]meta-iodohippuric acid ([131I]MIHA), the cumulatively excreted radioactivity consisted of >85% [131I]MIBG, with 6% of the dose excreted as free [131I]iodide, 4% as [131I]MIHA and 2.5% as an unknown iodine-131 labelled metabolite. Cumulative renal excretion rates of total radioactivity and of [131I]MIBG appeared to be higher in neuroblastoma and phaeochromocytoma patients than in carcinoid patients. Based on the excretion of small amounts of [131I]meta-iodobenzoic acid in two patients, a possible metabolic pathway for [131I]MIBG is suggested. The degree of metabolism was not related to the extent of liver uptake of radioactivity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Iodobenzylguanidine
  • Adolescent
  • Adult
  • Aged
  • Carcinoid Tumor / metabolism
  • Child
  • Child, Preschool
  • Contrast Media / metabolism*
  • Female
  • Humans
  • Iodine Radioisotopes / administration & dosage
  • Iodine Radioisotopes / urine*
  • Iodobenzenes / administration & dosage
  • Iodobenzenes / urine*
  • Iodohippuric Acid / metabolism
  • Kidney / physiology*
  • Male
  • Middle Aged
  • Neuroblastoma / metabolism*
  • Paraganglioma / metabolism
  • Pheochromocytoma / metabolism*


  • Contrast Media
  • Iodine Radioisotopes
  • Iodobenzenes
  • Iodohippuric Acid
  • 3-Iodobenzylguanidine