This research protocol makes pictures of brain tumors. The pictures are made with a positron emission tomography (PET) scanner. PET scans use radioactivity to "see" cancer cells. We are using a new kind of PET scan. The new PET scan is called [18F]-FACBC PET. We will compare this to the standard PET scan. The standard PET scan is called [11C]-methionine PET.

We expect these pictures will give us information about your tumor. We also hope to collect information about the amount of radioactivity exposure. We will measure radioactivity exposure to your tumor, brain and other organs. The research study results will be used to support the submission of an investigational new drug (IND) application to the Food and Drug Administration (FDA).

The purpose of this research is to: 1) perform both 3-[18F]-FACBC and [11C-methyl]-Lmethionine brain tumor PET imaging studies in patients with primary brain tumors who have previously been treated and are now suspect for having recurrence or progression of disease (a pilot study, n=20); 2) perform only 3-[18F]-FACBC PET imaging studies on an additional set of patients with primary brain tumors who have previously been treated and are now suspect for having recurrence (n=10) . 3) obtain organ/tissue and body radiation dosimetry information following i.v. injection of 3-[18F]-FACBC; 4) look for potential correlations between the scan results obtained from those patients enrolled to 03-028 and the patients' past medical treatment; The first set of 20 patients will agree to two PET studies. One study will involve the i.v.

administration of a fluorine-18 labeled amino acid analogue, 3-fluoro-aminocyclobutane carboxylic acid (3-[18F]-FACBC) with sequential brain and body PET imaging. The second study will involve i.v. administration of [11C-methyl]-L-methionine and head imaging only.

The additional set of 10 patients will undergo one PET study which will consist of the i.v.

administration of fluorine-18 labeled amino acid analogue, 3-fluoro-aminocyclobutane carboxylic acid (3-[18F]-FACBC) with one brain scan and one body scan only. The 3-[18F]-FACBC PET studies (n=30) will be performed under the Radioactive Drug Research Committee (RDRC) guidelines as defined and established by the Federal Drug Administration (FDA). [11C-methyl]-L-methionine is in the hospital formulary and is approved for imaging brain tumors at MSKCC. Our hypotheses include: 1) [18F]-FACBC has equal or better brain tumor imaging characteristics compared to [11C]-methionine; 2) [18F]-FACBC is not metabolized, and radiolabeled metabolites will not confound the interpretation of the images as can be the case with [11C]-methionine; 3) imaging recurrent brain tumors with [18F]-FACBC will be enhanced by lower brain (background) activity as compared to corresponding [11C]- methionine images; 4) the biodistribution of [18F]-FACBC and radiation dosimetry following i.v. administration of a 370 MBq (10 mCi) dose is safe and within FDA guidelines; 5) a 370 MBq (10 mCi) dose of [18F]-FACBC is sufficient for imaging brain tumors in a clinical setting; 6) the accumulation of [18F]-FACBC will correlate with the patients response to prior treatment and will provide prognostic information with respect to tumor progression and survival.

Inclusion Criteria:

• Registered patient at MSKCC.
• Child-bearing age females must be non-pregnant, non-lactating, and must be using adequate contraception or surgically sterile.
• Karnofsky score of 60 or greater.
• Children that can sit still for 60-90 minutes, without sedation, will be included in this protocol.

Exclusion Criteria:

• Patient cannot tolerate lying still for 90 minute sessions in the PET tomograph.

Up to 1 year