¹²³I-MIBG Scintigraphy and ¹⁸F-FDG PET in Neuroblastoma

The purpose of this study was to compare the diagnostic utility of 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy and 18F-FDG PET in neuroblastoma. Methods: A total of 113 paired 123I-MIBG and 18F-FDG PET scans in 60 patients with neuroblastoma were retrospectively reviewed. Paired scans were acquired within 14 days of each other. Results: For stage 1 and 2 neuroblastoma (13 scans, 10 patients), 18F-FDG depicted more extensive primary or residual neuroblastoma in 9 of 13 scans. 123I-MIBG and 18F-FDG showed equal numbers of lesions in 1 of 13 scans, and 3 of 13 scan results were normal. For stage 3 neuroblastoma (15 scans, 10 patients), 123I-MIBG depicted more extensive primary neuroblastoma or local or regional metastases in 5 of 15 scans. 18F-FDG depicted more extensive primary neuroblastoma or local or regional metastases in 4 of 15 scans. 123I-MIBG and 18F-FDG were equal in 2 of 15 scans, and 4 of 15 scan results were normal. For stage 4 neuroblastoma (85 scans, 40 patients), 123I-MIBG depicted more neuroblastoma sites in 44 of 85 scans. 18F-FDG depicted more neuroblastoma sites in 11 of 85 scans. 123I-MIBG and 18F-FDG were equivalent or complementary in 13 of 85 scans, and 17 of 85 scan results were normal. Conclusion: 18F-FDG is superior in depicting stage 1 and 2 neuroblastoma, although 123I-MIBG may be needed to exclude higher-stage disease. 18F-FDG also provides important information for patients with tumors that weakly accumulate 123I-MIBG and at major decision points during therapy (i.e., before stem cell transplantation or before surgery). 18F-FDG can also better delineate disease extent in the chest, abdomen, and pelvis. 123I-MIBG is overall superior in the evaluation of stage 4 neuroblastoma, especially during initial chemotherapy, primarily because of the better detection of bone or marrow metastases.