A Study Testing Whether Low-Dose Radiation Could Help the Immune System and Possibly Improve Early-Onset Alzheimer's Disease.

Inclusion Criteria: Alzheimer's diagnosis according to ICD-10 Ability to understand the clinical study and provide informed consent Early-onset disease Age older than 50 years Stable treatment with anti-dementia medication for at least 3 months Exclusion Criteria: * Prodromal Alzheimer's disease Mild cognitive impairment (MCI) Severe psychiatric disorders that could interfere with participation in the study Unstable or recently changed medication therapy Other neurodegenerative diseases or severe neurological disorders Uncontrolled chronic diseases that could increase the risk of complications Previous therapeutic brain irradiation Evidence of vascular cognitive impairment on MRI (Fazekas score \>1 and Wahlund score ≥10/30) Oncological disease (except skin cancer), active or in remission for less than 5 years Evidence of substance abuse (alcohol and/or other drugs) with dependence within the last 12 months (DSM-IV criteria) Active or recent (within 3 months) cerebral infection or hemorrhage Immunocompromised status History of seizures Dermatological scalp disease Women who are pregnant, breastfeeding, or planning to become pregnant during the study period Patient has a history of cancer (except non-melanoma skin cancer) Patient is taking antiepileptic medication Patient and legally authorized representative are unable to provide informed consent Patient with a history of focal neurological deficits (except vibratory peripheral neuropathy)