The role of meta-iodo [131I]benzylguanidine (MIBG) in the diagnosis and follow-up of neuroblastoma.

Fourteen scans employing the adrenergic blocking agent [131I]MIBG were performed on 10 children with neuroblastoma (NB) or ganglioneuroblastoma (GNB). The scans were negative in 5 cases, and 1 further case produced doubtful results in both the MIBG and CT scan tests. In 4 cases, very positive results were obtained with clear vision of the primary tumor and its metastases. In 1 case, which demonstrated partial differentiation of the outer part of the tumor mass toward GNB, a differentiated tumor specimen did not reveal significant uptake of the tracer. Half-lives of the tracer as measured by external detection in the period 24-48 h after injection were reduced after successful therapy. MIBG scanning appears to be a feasible indicator of NB adrenergic activity, and it can assume a primary role in the staging and follow-up of NB. Higher tumor uptake of the [131 I]MIBG and low background offer new perspectives in the radiometabolic treatment of MIBG.