Indication of 99mTc-MDP bone scan after 123I-MIBG scintigraphy in patients with neuroblastoma

Abstract

123I-MIBG (metaiodobenzylguanidine) scintigraphy and 99mTc-MDP bone scintigraphy (bone scan) are widely used in diagnosis and staging of NB. Consecutively using both methods lead to overall radiation exposure. As most of the patients need additional anesthesia to perform these diagnostic procedures, which accordingly increase the side effect, workload and expenditure. To minimize the exposure, side effect, workload and expenditure, we set the tasks to optimize the diagnostic algorithm. Determine the indications of bone scan after 123I-MIBG scintigraphy. Materials and Methods: 129 patients with NB were included in retrospective study who underwent both diagnostic procedures at interval of less than 30 days at the stage of initial diagnostic procedure using standard protocols. Out of 83 MIBG positive patients bone scan was able to detect metastatic lesions only in 48 patients. However, bone scan had revealed metastatic lesions in 3 out of 14 MIBG-negative patients. Bone scan is indicated only in MIBG-negative neuroblastoma patients; and in cases where the MIBG uptake cannot be determined for example after operative treatment or after starting of chemotherapy.