This phase I trial studies how well gallium Ga 68-DOTATATE positron emission tomography (PET)/computed tomography (CT) works in predicting tumor growth in patients with meningiomas. Giving Gallium Ga 68-DOTATATE before PET/CT scan may work better in predicting tumor growth in patients with meningiomas.

PRIMARY OBJECTIVES:

I. To assess the ability of imaging with gallium Ga 68-DOTATATE (68Ga-DOTATATE) positron emission tomography/computed tomography (PET/CT).

II. To assess a metabolic response to radiation therapy in meningiomas as measured by a reduction in the tumor to background ratio of the maximum standardized uptake values (SUV) of the tumor compared to background brain parenchyma.

OUTLINE:

Patients receive gallium Ga 68-DOTATATE intravenously (IV) over a few minutes and, after 60 minutes, undergo a PET/CT scan over 5-10 minutes 14 days before starting scheduled radiation therapy and 6 weeks after completion of radiation treatment.

Inclusion Criteria:

• Any meningioma with at least 10 mm measurable residual disease.
• Age 18 years or older.
• Planned radiation therapy for meningioma.
• Ability to understand and the willingness to sign a IRB approved written informed consent document in accordance with regulatory and institutional guidelines before study entry.
• No restriction based on language that would prohibit enrollment of the participant. IRB approved VTPS form will be utilized when non-English Speaking patient is enrolled

Exclusion Criteria:

• Neurofibromatosis type 1 or 2.
• Children.
• Pregnant.
• Contraindication to MR imaging.
• Body weight greater than 400 lbs (181.4kg).