The main objective is to detect with TESLA multiparametric 3 MRI, the MRI secondary changes to protontherapy irradiation and to correlate them with TEL mapping, physical dose and biological dose. A model should thus be able to be proposed at the end of the study.

Inclusion Criteria:

• Histologically proven or highly probable grade I meningiomas, histologically proven grade II meningiomas.
• Only meningiomas of the anterior and middle floors of the base of the skull are included.
• Indication of proton therapy retained in RCP and / or proton therapy technical staff (Caen site)
• Patient aged 18 or over
• Patient affiliated to a social security scheme
• Signature of informed consent before any specific procedure related to the study

Exclusion Criteria:

• History of brain or face irradiation.
• Implant or foreign body that can alter MRI imaging.
• Contraindication to MRI (pace maker, claustrophobia ...) - Hypersensitivity to gadoteric acid, to meglumine or to any medicine containing gadolinium
• Genetic radio sensitizing syndrome
• Known neurological comorbidities (stroke, Parkinson's, etc.) that may impact MRI data.
• Simultaneous participation in a therapeutic clinical trial
• Patient unable to undergo the trial follow-up for geographic, social or psychopathological reasons
• Pregnant or breastfeeding women
• Persons deprived of their liberty (see article L 1121-6 CSP),
• Adults who are the subject of a legal protection measure or unable to express their consent (see article L 1121-8)