• Patients must have the diagnosis of NB in accordance with the International Criteria, i.e., either histopathology (confirmed by the MSKCC Department of Pathology) or BM involvement plus elevated urinary catecholamines.

• Must have a history of tumor progression or recurrence or failure to achieve complete response with standard therapy.

• Patients must have MIBG-avid NB and evaluable disease on MIBG scan at time of enrollment on protocol

• Prior Therapy: At least 2 weeks should have elapsed since any biologic therapy. Three weeks should have elapsed since last dose of chemotherapy.

• Age \>1 year with a determination that radiation safety restrictions during therapy period can be implemented.

• Stem cells: Patients for high does must have an autologous hematopoietic stem cell product cryopreserved and available for re-infusion after MIBG treatment. Patients for low dose do not require cryopreserved autologous hematopoietic stem cell product available. The minimum dose for peripheral blood stem cells is 2 X106 CD34+ cells/kg.

• Minimum life expectancy of eight weeks

• Signed informed consent indicating awareness of the investigational nature of this program.

• Patients must have the diagnosis of malignant CCT i.e. malignant pheochromocytoma or malignant paraganglioma

• Patients must have MIBG-avid malignant CCT and evaluable disease on MIBG scan at time of enrollment on protocol

• Prior Therapy: At least 2 weeks should have elapsed since any biologic therapy. Three weeks should have elapsed since last dose of chemotherapy.

• Age between 1 and 21 years and able to cooperate with radiation safety restrictions during therapy period

• Stem cells: Patients must have an autologous hematopoietic stem cell product cryopreserved and available for re-infusion after MIBG treatment. The minimum dose for peripheral blood stem cells is 2 X106 CD34+ cells/kg.

• Minimum life expectancy of eight weeks.

• Signed informed consent indicating awareness of the investigational nature of this program.