High-risk meningiomas always require postsurgical radiation treatment. Recent evidence has shown that increased radiation therapy dose may be associated with increased intracranial control of disease. In order to better define the volume of radiation treatment, the addition of PET imaging with somatostatin receptor tracers adds additional information compared to encephalon MRI with MoC alone.The present study aims to investigate whether radiation treatment with higher doses than the standard and defined using PET imaging can be safe and at the same time effective in order to increase progression-free survival in high-risk meningiomas.

Inclusion Criteria:

• Age ≥ 16 years;
• Ability to express appropriate informed consent to treatment;
• Diagnosis of grade III meningioma (regardless of presence of residual) or diagnosis of recurrence of grade II meningioma (regardless of presence of residual) or first diagnosis of grade II meningioma with presence of residual;
• In case of recurrence, confirmation can be either histological or radiological;
• Not previous brain-level radiotherapy;
• Performance status: ECOG=0-2.

Exclusion Criteria:

• Refusal to radiation treatment (i.e., absence of signed informed consent);
• Other concomitant oncologic therapies
• Current pregnancy;
• Grade I meningiomas or Grade II meningiomas if operated on at first diagnosis with radical resection;
• Inability to perform MRI with MoC or PET.