Inclusion Criteria:

- Age: Patients must be >/= 3 years of age and able to cooperate for the PET CT scan
when registered on study.

- Diagnosis: Patients must have a diagnosis of neuroblastoma either by histologic
verification of neuroblastoma and/or demonstration of tumor cells in the bone marrow
with increased urinary catecholamine metabolites.

- Disease Status: Patients must have high-risk neuroblastoma with at least ONE of the
following:

- Recurrent/progressive disease at any time. Biopsy is not required, even if there is a
partial response to intervening therapy.

- Refractory disease (i.e. less than a partial response to frontline therapy, including
a minimum of 4 cycles of chemotherapy). No biopsy is required for eligibility for
this study.

- 123I-MIBG Uptake: Patients must have MIBG evaluable disease which is defined as
evidence of uptake into tumor at >/= one site within 4 weeks prior to entry on study
and subsequent to any intervening therapy.

- 131I-MIBG Therapy: Patients must meet eligibility criteria for 131I-MIBG therapy.

- Reproductive Function: All post-menarchal females must have a negative beta-HCG
within 2 weeks prior to receiving the dose of 124I-MIBG. Males and females of
childbearing potential must practice an effective method of birth control while
participating on this study, to avoid possible damage to the fetus.

Exclusion Criteria:

- Pregnancy or lactating with the intent of breast feeding.

- Patients who require general anesthesia for MIBG imaging studies.