A Prospective Exploratory Clinical Trial to Evaluate the Pre- and Post-Treatment Changes of HeLaXON, a Low-Dose Radiation Therapy Device, in Patients with Mild AD Dementia

INTERVENTION: Medical Device : Participants who are determined to be eligible for this clinical trial will be randomly assigned in a 1:1 ratio to either the experimental group (intervention group: radiation exposure) or the control group (Sham group). Participants assigned to the experimental group will receive low‐dose whole‐brain radiation at a dose of 0.04 Gy per session, twice weekly for 3 weeks, for a total of si Xsessions and a cumulative dose of 0.24 Gy, using the investigational medical device. Participants assigned to the control group will undergo the same investigational medical device procedures as those in the experimental group. These procedures will be performed in an identical manner, including determination of the radiation target area, use of a head‐and‐neck immobilization mask and fixation device, and reproduction of the sounds and lighting generated during device operation; however, no actual radiation will be delivered. Efficacy and safety assessments will be conducted at baseline and at 1, 6, and 12 months after treatment. At each visit, demographic information, vital signs, medical history, cognitive function assessments, neurological examinations, laboratory tests, and other evaluations will be performed in accordance with Section 1.3, “Schedule of Assessments,” of the protocol. CONDITION: Mental and behavioural disorders PRIMARY OUTCOME: Clinical Dementia Rating scale – Sum of Box, CDR‐SB SECONDARY OUTCOME: Adverse Event(CTCAE V6.0) Alzheimer`s disease assessment scale‐Korea‐Cognitive Subscale‐13, ADAS‐K‐Cog‐13 Change in amyloid deposition converted to the Centiloid (CL) scale based on SUVR Korea‐Mini‐Mental Status Examination‐2, K‐MMSE‐2 Korean Instrumental Activities of Daily Living, K‐iADL laboratory tests Vital signs / physical examination INCLUSION CRITERIA: 1. Male or female subjects aged = 60 years and = 85 years. 2. Subjects who meet the criteria for Mild Dementia (Stage 4) according to the NIA‐AA (New Diagnostic Criteria for Alzheimer’s Disease) diagnostic criteria. 3. Subjects who meet all of the following criteria at screening: ? A score of = 20 and = 26 on the Korean Mini‐Mental State Examination‐2 (K‐MMSE‐2). ? A CDR Global Score of 1 (or a CDR Global Score of 0.5 or 1 with a CDR‐SB score of = 4.5 and = 9.0). ? A Memory Bo XScore of = 0.5. 4. For subjects taking a cholinesterase inhibitor (donepezil, galantamine, or rivastigmine) for symptom control, the dose must have been stable for at least 12 weeks prior to the screening visit. 5. Subjects with a positive finding of cerebral amyloid deposition on amyloid PET. 6. Subjects who are able to undergo the cognitive function assessments and imaging examinations required in this clinical trial. 7. Subjects who have a caregiver who can provi