FLT-PET Imaging of Brain Tumors in Children

Although pediatric central nervous system tumors are rare, they are a significant contributor
to morbidity and mortality in children. Tumor staging, detecting recurrent tumor, and
assessing the response to therapy are critical in the treatment of brain tumors, but current
imaging methods have major limitations in providing such information. The objective of this
study is to validate 3'-deoxy-3'-[F-18] fluorothymidine (18F-FLT) as a measure of tumor
proliferation and to demonstrate the utility of 18F-FLT as a PET imaging agent in children
with central nervous system tumors. The proposed studies will evaluate 18F-FLT PET in three
groups:

1. Children with a new diagnosis of central nervous system tumor.

2. Children in whom conventional imaging has raised concern for possible recurrence of a
central nervous system tumor.

3. Children receiving post-operative chemotherapy for a central nervous system tumor.

In these three groups, correlation of 18F-FLT uptake with tumor histopathology and patient
outcome will be used to assess the utility of 18F-FLT for grading tumors at diagnosis, for
accurate identification of tumor recurrence, and for early assessment of the response to
chemotherapy.

Inclusion Criteria:

- age 21 years or less

- capable of achieving imaging without need for sedation or anesthesia (typically age 8
years or greater, but there is no lower limit for age for eligibility)

- Karnofsky Performance Status of 50 or greater in subjects age 12 years or greater, for
age less than 12 years a Lansky play scale of 50% or greater

- Patients receiving steroids and/or anti-seizure medications are eligible

Exclusion Criteria:

- clinically active infection

- pregnancy or breast-feeding

- serious intercurrent medical illness

- require emergency surgical intervention that would be inappropriately delayed by
FLT-PET imaging