This is a prospective, open-label, multicentric study designed to correlate the dose delivered to the hippocampus with declarative memory deficits 2 years after radiotherapy treatment in a paediatric population who had received brain irradiation between the ages of 4 and 12 for a brain tumour.

In order to meet this objective, several neuropsychological assessments consisting of parental questionnaires and cognitive tests will be carried out during the course of the study, at the following two stages:

• A 1st assessment at patient inclusion, i.e. 2 years after the end of radiotherapy treatment,
• And a second assessment 2 years after patient inclusion, i.e. 4 years after the end of radiotherapy treatment.

A retrospective assessment of the patient's neurocognitive level 1 year before the diagnosis of the disease will also be carried out at inclusion, with the parents completing a questionnaire specifically designed for the trial.

In addition, patients who have received their radiotherapy treatment at the IUCT-O will be offered participation in the ancillary imaging study. If the parents and the patient agree, multimodal MRI scans specific to the study (without injection of contrast) will be performed at inclusion and 2 years after inclusion.

Imaging and radiotherapy data will be collected in parallel using the PediaRT software used in current practice (collection of radiotherapy dosimetric data as well as standard MRI examinations pre-operatively, post-operatively, and at the 2-year and 4-year follow-up).

130 patients will be included in this study.

Inclusion Criteria:

1. Patient who has received localised brain irradiation or craniospinal irradiation for a brain tumour whose treatment includes first-line radiotherapy.
2. Patient with one of the following tumour types: ependymomas, medulloblastomas, malignant germ cell tumours, craniopharyngioma, pinealoblastoma.
3. Patient aged between 4 and 12 years at the time of radiotherapy treatment.
4. End of irradiation within 2 years (+/-3 months) prior to inclusion.
5. Patient having been treated by photontherapy or proton therapy.
6. Sufficient visual, auditory (with authorised hearing aid) and oral or written expression capacity to carry out the neuropsychological tests properly.
7. Proficiency in the French language by the patient and parent(s).
8. Patient affiliated to a Social Security scheme in France.
9. Informed consent signed by the patient/legal parent(s)/guardian(s) in accordance with French law and Good Clinical Practice.

Exclusion Criteria:

1. Patient presenting with severe ataxia.
2. Patient with a recurrence of the disease.
3. Not applicable since protocol version 2. Metastatic patient.
4. Any contraindication to MRI for patients included in Toulouse (i.e. in particular patients with a pacemaker or cardiac defibrillator, implanted equipment activated by an electrical, magnetic or mechanical system, patients with haemostatic clips on intracerebral aneurysms, patients with orthopaedic implants, claustrophobic patients).
5. Patients undergoing psychostimulant or psychotropic treatment (in particular methylphenidate, antidepressants).
6. Any psychological, family, geographical or sociological condition that prevents compliance with medical monitoring and/or the procedures set out in the study protocol.
7. Patients deprived of their liberty or under legal protection.
8. Severe posterior fossa syndrome with akinetic mutism.