131I-Metaiodobenzylguanidine (131I-MIBG) Therapy for Relapsed/Refractory Neuroblastoma

Inclusion Criteria: * Diagnosis: * Relapsed/refractory neuroblastoma with original diagnosis based on tumor histopathology or elevated urine catecholamines with typical neuroblastoma cells in the bone marrow * Metastatic pheochromocytoma * Age \>1 year and able to cooperate with radiation safety restrictions during therapy period * Karnofsky or Lansky performance status of ≥ 50% * Life expectancy: patients must have a life expectancy of at least 8 weeks * Disease status: Failure to respond to standard therapy (usually combination chemotherapy with or without radiation and surgery) or development of progressive disease at any phase of standard therapy (any new lesion or an increase in size \>25% of a pre-existing lesion). Patients may enter this study with or without re-induction therapy for recurrent tumor. * Disease must be evaluable by MIBG scan. A positive MIBG scan must be present within 8 weeks prior to study entry and subsequent to any intervening therapy. If the patient has only one MIBG positive lesion and that lesion was radiated, a biopsy must be done at least 4 weeks after radiation was completed and must show viable neuroblastoma. * Stem Cells: If a patient does not have a hematopoietic stem cell product available for re-infusion after MIBG treatment, they may not receive a 131IMIBG dose \>12 mCi/kg. Patients must have a hematopoietic stem cell product available for re-infusion after MIBG treatment at doses of \> 12 mCi/kg. The minimum quantity for peripheral blo…