Effect of Low Dose Radiotherapy on Brain Amyloidosis in the Treatment of Alzheimer's Disease

Inclusion Criteria: * Ability to understand the clinical trial and give an informed consent * Clinical diagnosis of prodromal AD, or mild or moderate AD * Ability to undergo neurocognitive assessment at baseline visit, alone or accompanied by a caregiver * Amyloid PET scan positivity * Ability to follow the 5-days RT regiment, alone or accompanied by a caregiver Exclusion Criteria: * Inclusion in another disease modifying clinical trial * Previous therapeutic brain irradiation * Evidence of vascular cognitive impairment on Magnetic Resonance Imaging (MRI) (Fazekas score \>1 and Wahlund score \>=10/30) * Oncologic disease (excluding skin cancer) active or in remission from less than 5 years * Evidence of substance abuse (alcohol and/or other drugs) with a dependence during the previous 12 months (DSM-IV criteria) * Presence of subdural hygroma's, subdural hematomas or hydrocephalus * Significant psychiatric comorbidity as assessed during the clinical evaluation by the neurologist/geriatrician in charge * Active or recent (within 3 months) cerebral infection/haemorrhage * Immunocompromised status * Prior history of seizure * Dermatological skin disease of the scalp * Women who are pregnant or breast feeding or who intend to become pregnant during the course of the study; * Lack of safe contraception, defined as: female participants of childbearing potential, not using and not willing to continue using a medically reliable method of contraception for the entire study duration…