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: ≥ at least 8 weeks

          -  Disease status: Failure to respond to standard therapy or development of progressive
             disease at any time.

          -  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: Patients must have a hematopoietic stem cell product available for
             reinfusion after MIBG treatment at doses of > 12 mCi/kg.

          -  Have acceptable organ function as defined below within 7 days of enrollment:

               -  Bone Marrow: ANC ≥750 X 109 /L and platelets ≥50,000 X 109 /L without transfusion
                  if stem cells are not available (any ANC or platelet allowed if stem cells
                  available)

               -  Renal: Creatinine ≤3x upper limit of normal

               -  Hepatic: Bilirubin ≤2x upper limit of normal; AST/ALT ≤10x upper limit of normal

               -  Cardiac: Ejection fraction ≥45% on echocardiogram

               -  Pulmonary: normal lung function as manifested by no dyspnea and/or oxygen
                  saturation ≥ 88% on room air.

          -  Prior Therapy: Patients must have recovered from all acute toxicities (defined as
             CTCAE 4.0 ≤ grade 1) associated with any prior therapy, and:

               -  Myelosuppressive chemotherapy: At least 2 weeks should have elapsed since any
                  chemotherapy causing myelosuppression

               -  Biologic (anti-neoplastic agent): At least 7 days should have elapsed since the
                  completion of therapy with a biologic agent.

               -  Monoclonal antibodies: At least 3 half-lives should have elapsed since therapy
                  with a monoclonal antibody

               -  Radiation therapy: Three-months should have elapsed in the case of completing
                  radiation to any of the following fields: craniospinal, total abdominal, whole
                  lung, total body irradiation). For all other sites of radiation, at least 2 weeks
                  should have relapsed.

               -  Cytokine therapy (e.g. G-CSF, GM-CSF, IL-6, IL-2): must be discontinued a minimum
                  of 24 hours prior to MIBG therapy.

          -  Voluntary written informed consent

        Exclusion Criteria:

          -  Patients with disease of any major organ system that would compromise their ability to
             withstand therapy.

          -  Because of the teratogenic potential of the study medication, no patients who are
             pregnant or lactating will be allowed. Patients of childbearing potential must
             practice an effective method of birth control while participating on this study, to
             avoid possible damage to the fetus.

          -  Known allergy to any of the agents or their ingredients used in this study.

          -  Patients who are on hemodialysis

          -  Patients with untreated positive blood cultures or progressive infections as assessed
             by radiographic studies