124I-Metaiodobenzylguanidine (MIBG) PET/CT Diagnostic Imaging and Dosimetry for Patients With Neuroblastoma: A Pilot Study

Accurate radiation dose evaluation is important in patients with malignant tumors, and this
is especially critical in children with NB who will be receiving several dose of therapeutic
131I. The accurate quantification of the isotope-labeled analog can only be achieved by using
positron emission compounds, such as 124I. Unlike planar images, which were used to obtain
kinetic information, and SPECT reconstruction modalities that were aimed to assess the
spatial distribution of radioactivity, 3D PET imaging-based dosimetry is a method which
provides a more accurate estimation of the cumulated radioactivity distribution. Because PET
provides better quantitative accuracy, when compared to SPECT regarding the tissue absorbed
information, we hypothesize PET would better correspond with tumor response and normal organ
toxicity. Early studies using I-124 for dosimetry in thyroid cancer have been promising.

Demonstration of the feasibility and accuracy of this new imaging modality, with the
excellent prospect for more accurate dosimetry, will improve tumor localization and optimize
therapeutic dosing with 131I-MIBG. The results of our work may potentially have also
implications in the study of other neuroendocrine tumors. The Section of Nuclear Medicine and
the Laboratory of Functional Imaging at the University of California, San Francisco, are
equipped with state of the art instruments and is run by a highly skilled staff which will
guarantee the success of the proposed research.

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 - To be eligible for the MIBG pre-therapy dosimetry:

- 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.

- Imaging only cohort

- For patients participating in the imaging cohort only, patients with high-risk
neuroblastoma are eligible at any time (during initial treatment or during treatment
of relapsed/refractory disease) as long as they meet the requirements.

- 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.

- Patients must meet eligibility criteria for 131I-MIBG therapy in order to participate
in the dosimetry portion.

- 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.