18F-FLT PET Imaging in Assessing Tumors and Measuring Response in Younger Patients With Brain Tumors

Inclusion Criteria

• Subjects may be enrolled at one of three time points in the clinical course of disease: * Study 1 (New Diagnosis): ** Pediatric patients with newly diagnosed primary central nervous system tumors undergoing surgical resection/biopsy within 21 days or who, within the prior 21 days, have undergone resection/biopsy with substantial residual (greater than half as assessed by the surgeon) tumor * Study 2 (Possible Tumor Recurrence): ** Pediatric patients with a history of treated primary central nervous system tumor, in whom standard imaging has raised concern for tumor recurrence; tumor tissue for histological analysis must be available from a biopsy/resection planned within the next 21 days or from a prior resection/biopsy if no current biopsy material is available * Study 3 (Response to Therapy): ** Pediatric patients with a primary central nervous system tumor who will be starting a new regimen (standard or experimental) of chemotherapy within 21 days, have not received radiation therapy during the past six months, and who will not be receiving radiation therapy during the first two cycles of chemotherapy
• Patients should be capable of achieving imaging without the need for sedation or anesthesia
• Karnofsky performance status >= 50 for patients >= 12 years of age; for children < 12 years of age, the Lansky play scale >= 50% can be substituted
• Signed informed consent by subject (age >= 18 years) or by parent/guardian (subject age < 18 years); information will be provided to potential subjects and their parents/guardians (as appropriate) by oral discussion with opportunity for question and answer and the written informed consent document; subjects less than 18 years of age capable of giving assent will be included in these discussions and will be asked for written assent on the same document as the parents/guardians give consent; if feasible, both parents (or guardians) will be included in these discussions and will be asked to sign the written consent document; if a second parent or guardian is unavailable, this will be explained in writing on the written consent document; if subjects age 18 years or older are unable to provide informed consent, then they will not be enrolled in this study
• Patients receiving glucocorticoids and/or anti-seizure medications are eligible for this study

Exclusion Criteria

• Clinically active infection; an active infection may alter the biodistribution of 18F-FLT
• Known pregnancy or breast feeding; pregnant women are excluded as the effects of 18F-FLT on the fetus are not known, and there is the potential for teratogenic or abortifacent effects; within 48 hours prior to a PET scan, a pregnancy test will be obtained in all female participants of child bearing potential to confirm non-pregnant status; because there is an unknown, but potential, risk of adverse effects in nursing infants, breastfeeding should be discontinued before the mother receives 18F-FLT
• Serious intercurrent medical illness
• Patients requiring emergency surgical intervention that would be inappropriately delayed by FLT-PET imaging