For the purpose of this research, investigator will constitute several cohorts of patients, treated either by intensity-modulated radiotherapy, stereotactic radiotherapy or proton-therapy. This will allow better understanding the cognitive and anatomical damages caused by new radiotherapy techniques and better understanding how ionising radiation (X-rays or protons) acts in the long term on brain tissue. Longitudinal follow-up will be multimodal, based on yearly multi-parametric brain MRI to assess morphological changes, in relation with dosimetric data as well as neuropsychological performances, health-related quality of life, anxiety and depression disorders, memory tasks, and socio-professional reintegration. This will notably make it possible to evaluate the relationship between dosimetric data, age at the time of treatment, region of the brain irradiated, type of radiation used, dose per fraction, neurocognitive and neuro-anatomical consequences. A Normal Tissue Control Probability (NTCP) model will be also developed. Overall, the results of this study should contribute to the improvement of treatment techniques, in particular by preserving as much as possible the significant cerebral zones (hippocampi, frontal lobe, sub-ventricular zones, etc.), and to the management of patients by proposing appropriate support measures. In the proton-therapy cohort, evaluations will make it possible to establish more precisely the place that this new irradiation strategy should occupy in the management of low grade meningioma. Importantly, investigator have planned to constitute a last cohort, with subjects free of any neurological disease, to make it easier the interpretation of cognitive performances over time among patients in the three brain radiation cohorts.