Multi-Tracer PET Assessment of Primary Brain Tumors

Inclusion Criteria:

Three different adult patient groups will be eligible for inclusion in this study:

* Group 1: Adult patients with compelling evidence of primary brain tumor based on clinical and MRI or CT imaging characteristics that have not yet received surgery, histological diagnosis, or any tumor-directed therapy. Such evidence will include: MRI or CT scan-documented mass lesion within the brain, accompanied by anatomically appropriate neurological signs and symptoms, in the absence of a probable competing diagnosis such as brain abscess or primary intracranial hematoma.
* Group 2: Newly diagnosed primary malignant brain tumors (WHO Grade II - IV glial-based tumors) who have not had a complete surgical resection and by contrast MRI or CT have residual tumor greater than 1.0 cm in diameter and will be receiving radiotherapy and/or chemotherapy.
* Group 3: Patients with probable or possible recurrent primary brain tumor as determined by standard clinical criteria or MRI or CT imaging. The abnormality must be greater than or equal to 1.0 cm in diameter by contrast MRI or CT or show changes on non-enhancing MRI sequences (T2 or FLAIR).

  * Patients must be 18 years or older for inclusion in this study. There is little experience with the safety of \[18F\]FLT in children, and the risks associated with radiation exposure may be increased for children under 18 years old as well.
  * Karnofsky performance status ≥ 60%.
  * Patients must document their willingness to be followed for at least 24 months after recruitment by signing informed consent documenting their agreement to have clinical endpoints and the results of histopathologic tissue analysis (when tissue becomes available from routine care) entered into a research database.
  * All patients, or their legal guardians, must sign a written informed consent and HIPAA authorization in accordance with institutional guidelines.
  * Determination of pregnancy status: Female patients that are not postmenopausal or surgically sterile will undergo a serum pregnancy test prior to each set of multi-tracer PET scans. A negative test will be necessary for such patients to undergo research PET imaging.
  * Pre-treatment laboratory tests for patients receiving \[18F\]FLT must be performed within 21 days prior to study entry. These must be less than 2.5 times below or above the upper or lower limit range for the respective laboratory test for entry into the study. In those instances where a baseline laboratory value is outside of this range, then such a patient will be ineligible for enrollment. For the follow-up scanning sessions after therapy has been instituted, laboratory testing will also be required due to the use of FLT. The patients have brain tumors and will receive various forms of therapy; therefore many routine laboratory tests may not be within the typical normal range. As such, a factor of 4.0 times above or below the upper or lower value for the normal range for any laboratory test will be used to determine the acceptable range for the 2nd and possible 3rd imaging timepoints. The baseline laboratory testing will include liver enzymes (ALT, aspartate aminotransferase (AST), alkaline phosphatase (ALK), LDH), bilirubin (total), serum electrolytes, complete blood count (CBC) with platelets and absolute neutrophil counts, prothrombin time, partial thromboplastin time, blood urea nitrogen (BUN), creatinine. Previous urinalysis abnormalities will not preclude the patient from being studied. For those patients receiving coumadin or another anticoagulant the upper limit for prothrombin time or partial thromboplastin time must not exceed 6 times the upper limit of the normal range.

Exclusion Criteria:

* Patients with clinically significant signs of uncal herniation, such as acute pupillary enlargement, rapidly developing motor changes (over hours), or rapidly decreasing level of consciousness, are not eligible.
* Patients with known allergic or hypersensitivity reactions to previously administered radiopharmaceuticals. Patients with significant drug or other allergies or autoimmune diseases may be enrolled at the Investigator's discretion.
* Patients who are pregnant or lactating or who suspect they might be pregnant. Serum pregnancy tests will be obtained prior to each set of multi-tracer PET scans in female patients that are not postmenopausal or surgically sterile.
* Adult patients who require monitored anesthesia for PET scanning.
* HIV positive patients due to the previous toxicity noted with FLT in this patient group.
* Patients who have undergone surgery or receive any previous tumor-directed therapy for their brain tumor.