Positron Emission Tomography Using Fluorothymidine F 18 in Finding Recurrent Disease in Patients With Gliomas

DISEASE CHARACTERISTICS: Radiological or established histological diagnosis of glioma WHO grade 2-4 disease Presence of a new or enlarging enhancing lesion on gadolinium-enhanced MRI after prior radiotherapy Differentiation of recurrent tumor from radiation necrosis is not possible No clinically significant signs of uncal herniation, including any of the following: Acute pupillary enlargement Rapidly developing (i.e., over hours) motor changes Rapidly decreasing level of consciousness PATIENT CHARACTERISTICS: Platelet count ≥ 75,000/mm^3 WBC ≥ 3,000/mm^3 Gamma-glutamyl-transferase ≤ 5 times upper limit of normal (ULN) Absolute neutrophil count ≥ 1,500/mm^3 Hemoglobin ≥ 10 g/dL SGOT and SGPT ≤ 2 times ULN Alkaline phosphatase ≤ 2 times ULN Lactic dehydrogenase ≤ 2 times ULN Direct and total bilirubin normal Amylase normal Haptoglobin normal Serum electrolytes normal CBC with platelets normal PT, PTT normal BUN and creatinine normal Not pregnant or lactating Urinalysis normal Negative pregnancy test Female patients must be postmenopausal for ≥ 1 year or surgically sterile, or on 1 of the following methods of birth control for ≥ 1 month: IUD, oral contraceptives, Depo-Provera, or Norplant These criteria can be waived at the discretion of the investigator if the patient's intracranial tumor is considered life threatening and the 1-month wait required is not in the best interest of the patient No known allergic or hypersensitivity reactions to previously administered radiopharmaceuticals No known HIV positivity Not requiring monitored anesthesia for positron emission tomography scanning PRIOR CONCURRENT THERAPY: Concurrent biopsy or neurosurgical procedure for diagnostic and/or therapeutic purposes for this cancer allowed Concurrent surgery for this cancer allowed