For most brain tumors, radiation treatment is guided by a Magnetic Resonance Imaging (MRI) scan. In this study, information from a special scan, called a Positron Emission Tomography/ Computed Tomography (PET/CT) scan using an amino acid called Fluorine-18-L-dihydroxyphenylalanine (18F-DOPA) will also be used. This type of scan has shown promise in being able to better distinguish tumor from normal brain tissue and may help to more accurately plan radiation treatment. This type of scan can also assist the radiation oncologist in identifying the most aggressive regions of the tumor. The goal of this study is to compare the 18F-DOPA PET/CT scan with the MRI scan for identifying where the disease is that needs to be treated with radiation.

Inclusion Criteria:

• Age ≥7 years.
• Biopsy confirmed newly diagnosed or recurrent WHO Grade II or Grade III malignant glioma.
• CT simulation, 18F-DOPA PET imaging, and standard of care pre-radiotherapy MRI scans to be performed at Mayo Clinic Rochester.
• Willing to sign release of information for any follow-up records.
• Provide informed written consent.

Exclusion Criteria:

• Patients diagnosed with WHO grade IV malignant glioma.
• Patients previously treated with radiation therapy.
• Unable to undergo MRI scans with contrast (e.g. cardiac pacemaker, defibrillator, kidney failure).
• Unable to undergo an 18F-DOPA PET scan (e.g. Parkinson's Disease, taking anti-dopaminergic, or dopamine agonist medication or less than 6 half-lives from discontinuance of dopamine agonists)
• Pregnant women
• Nursing women
• Men or women of childbearing potential who are unwilling to employ adequate contraception

Newly diagnosed or recurrent WHO Grade II and Grade III Glioma patients.