Objective: To evaluate clinical utility of I-131-MIBG scan in patients with Neuroblastoma in last 8 years.

Method: Diagnosed cases of H/P proven Neuroblastoma from Jan-2000-Dec-2008 were included in the study. I-131-MIBG whole body scan was acquired 24&48-hours post I/V-injection of 16-23MBq of I-131-MIBG. Patients were given lugol’s solution prior to scan to block thyroid. Images acquired with high-energy-parallel-hole-collimator and 20% windows centered at 364keV. Follow-up scan was also done if requested by referring service. Correlation with bone marrow biopsy, bone scan and radiological modalities was also performed.

Results: 17-patients; Mean age 2yrs (Range: 6m-10 yrs); 14M/3F, presented for I-131-MIBG imaging. Baseline scan was performed for these patients with Stage-3, 4 & 4s and showed sensitivity of 70%, 100% & 0% respectively. 2/10 Patients with stage-3 disease had negative scan due to disease in thoracic region while 1 with abdominal disease was also negative (Sensitivity 70%). 2-patients with negative scans had Stage 4s disease which resolved spontaneously. 5-patients of Stage-4 had positive bone marrow infiltration on biopsy and 4 had positive bone scan findings which correlated well with MIBG avidity. On follow-up 4-patients with Stage-3 disease had repeat scan; findings of which correlated well with CT/USG abdomen. Progression of disease was noted in 2/4 patients on follow-up scans despite receiving chemotherapy and radiotherapy. Complete resolution of disease was noted in other 2-patients.

Conclusion: I-131-MIBG scan is highly sensitive in the detection of primary disease as well as distant metastases especially in Stage-4 Neuroblastoma. Follow-up I-131-MIBG scan also indicates response to therapy.