IMAGING SECONDARY NEUROENDOCRINE TUMORS OF THE LIVER - COMPARISON OF I-123 METAIODOBENZYLGUANIDINE (MIBG) AND IN-111-LABELED OCTREOTIDE (OCTREOSCAN)

Functional imaging of neuroendocrine tumours with Octreoscan and I-123 -metaiodobenzylguanidine (MIBG) is important for assessment prior to v arious therapies and assessing response. The two imaging methods have not been directly compared in hepatic neuroendocrine tumours. Patients (n=18) were studied with both imaging techniques. The sensitivity of Octreoscan was 94%, and that of MIBG 39%. No previously occult primary sites were detected. Concurrent octreotide therapy did not reduce the sensitivity of Octreoscan. Widespread bone metastases were seen in tw o post-liver-transplant patients using Octreoscan. Octreoscan is a sen sitive means of detecting hepatic neuroendocrine tumours, and the more specific technique. MIBG has poor sensitivity, reducing its clinical utility. Therapy with I-131 MIBG is likely to be applicable to relativ ely few patients.