Executive summary
Low dose whole brain radiation therapy (LDRT) for Alzheimer’s disease has moved from case reports to randomized, sham controlled trials, and two new trials are opening in late 2026. The evidence remains early, with fewer than 40 treated patients across published human studies as of October 2026, but every study to date reports the treatment was tolerated without serious adverse events.
The indication matters to radiation oncology leadership for a practical reason. Every element of delivery, from CT simulation to whole brain planning to QA, already exists in a working department. If a definitive trial reads out positive, demand would arrive on linear accelerators and physics teams that are already running at capacity.
This brief covers what the biology suggests, what the human trials show, what changed in 2026, and what a department would need in place to deliver this safely. Team Net Medical’s view is that leadership should treat LDRT for Alzheimer’s as a monitored opportunity, with a named owner and a defined review point, rather than a program to launch today.
The biology
The rationale for LDRT rests on two targets, amyloid plaque and chronic neuroinflammation, and on the observation that radiation behaves differently at doses far below oncologic levels.
Alzheimer’s pathology includes extracellular amyloid plaques, intracellular neurofibrillary tangles, and a sustained inflammatory response driven by activated microglia. Animal studies have shown that fractionated low doses reduce amyloid burden, lower inflammatory cytokine expression, and shift microglia toward a reparative phenotype associated with debris clearance. Proposed mechanisms include direct destabilization of amyloid fibrils and increased blood brain barrier permeability that allows immune cells to reach and clear plaque.
An April 2026 review in the International Journal of Molecular Sciences summarized these findings across mouse, rat, and other in vivo models. The authors note that beneficial effects are most consistent with fractionated regimens in the range of 0.1 to 1 Gy per fraction, with cumulative doses between roughly 3 and 10 Gy. That range is an order of magnitude below a standard palliative whole brain course and well below the threshold associated with radiation induced cognitive decline.
The word “low” covers a wide span in this literature. Published human protocols range from 24 cGy total, delivered as six fractions of 4 cGy, up to 10 Gy delivered as five fractions of 2 Gy. Which end of that range works, if either, is the central open question.
The human evidence so far
Four published human studies and one interim analysis make up the clinical record. All report tolerability. None is large enough to establish efficacy.
| Study | Where | Patients | Dose and schedule | Design | Main finding | Published |
|---|---|---|---|---|---|---|
| Cuttler et al. | Toronto, Canada | 4 | Repeated low dose CT scans of the brain | Open label pilot | Minor quantitative improvement in 3 of 4 patients | 2021 |
| Rogers et al. | United States | 5 | 10 Gy in 5 fractions over one week | Open label pilot | 4 of 5 improved or stable on MMSE-2 at one year; only side effect was temporary hair loss | 2023 |
| Rogers et al., phase 2a | United States | 5 | Low dose whole brain, same group | Phase 2a | Quality of life stable in all 5; possible modest changes in hippocampal amyloid and FDG PET | 2024 conference |
| Kim et al., interim | South Korea, multicenter | 15 | Sham, 24 cGy, or 300 cGy in 6 fractions over 3 weeks | Randomized, single blind, sham controlled | No adverse events; cognitive differences between groups not statistically significant at 6 months | 2025 |
| Chung et al. | South Korea, single center | 9 | Sham, 24 cGy, or 300 cGy in 6 fractions | Exploratory imaging substudy | Measurable conductivity and diffusion MRI changes; conductivity in the left fusiform gyrus correlated with MMSE (r = 0.84) | April 2026 |
The United States pilot used the most radiation. Five patients with early Alzheimer’s dementia received 2 Gy a day for five days. At one year, three had improved and one was stable on the Mini Mental State Examination, and the three who improved reached the average range. The authors describe the result as hypothesis generating and call for larger randomized trials.
The Korean phase II trial (NCT05635968) is the first randomized, sham controlled study. It enrolled patients with amyloid confirmed by PET, MMSE 13 to 24, and CDR 0.5 to 1. The interim analysis of 15 patients reported no adverse events and group differences that did not reach significance. Per the registry, the study completed in April 2025 and final results are awaited.
Together, these studies answer the safety question at the dose levels tested and leave the efficacy question open.
What is new in 2026
Three developments this year move the field from pilot work toward controlled evidence.
A double blind, sham controlled trial opens in Korea. NCT07863011, sponsored by ReadyCure Inc., is a randomized, subject and assessor blinded, sham controlled exploratory trial in patients with mild Alzheimer’s dementia. It uses a dedicated low dose radiation device called HeLaXON 1X rather than a conventional linear accelerator. The registry lists the study as recruiting, with an estimated start date of October 26, 2026 and primary completion in March 2028. This is the first LDRT trial in Alzheimer’s to blind both patient and assessor.
A European feasibility trial targets early onset disease. NCT07564700, the HOPE trial at Heinrich Heine University in Düsseldorf, is a randomized clinical feasibility study of LDRT as an immunomodulatory therapy for early onset Alzheimer’s disease. As of April 2026 it was not yet recruiting, with an estimated start of May 2026 and primary completion in December 2027.
Imaging biomarkers appear for the first time. The April 2026 Diagnostics paper from Kyung Hee University is the first quantitative MRI evaluation of LDRT in Alzheimer’s patients. Using conductivity mapping and diffusion tensor imaging in nine patients, the authors found measurable tissue changes six months after treatment and a strong correlation between conductivity in the left fusiform gyrus and cognitive scores. The study was small, non randomized, and unblinded, so the authors present it as hypothesis generating. Its value is that future trials now have a candidate objective endpoint beyond cognitive testing.
What it would take to deliver
A department that already delivers whole brain radiation has most of the technical pieces in place. The gaps are in dose verification at very low output, in patient selection, and in the operational load a new non cancer population would add.
Physics and dosimetry. Standard linear accelerators are commissioned and calibrated around 2 Gy fractions. A fraction of 4 cGy, as used in the Korean low dose arm, sits at the edge of what monitor unit linearity and daily output checks are designed to verify. A physics team would need to validate output at low monitor unit settings, confirm beam flatness and symmetry for short beam on times, and document the method in a protocol specific QA plan. The 2 Gy per fraction regimen used in the United States pilot needs no special commissioning, which is one reason it was chosen.
Treatment planning. Whole brain planning is routine. Trials to date have used opposed lateral fields or simple techniques with standard immobilization. Hippocampal avoidance is not part of any published Alzheimer’s protocol, since the hippocampus is a target rather than a structure to spare.
Patient selection and consent. Every trial has required amyloid confirmation on PET, a defined MMSE and CDR range, and a caregiver able to report on function. Patients with prior cranial radiation, seizure disorders, or scalp disease were excluded. A department would need neurology and nuclear medicine partners to run this pathway, and a consent process written for a population with impaired capacity.
Safety monitoring. Published protocols track cognition, quality of life, ophthalmologic status, and imaging at baseline, 6 months, and 12 months. The only side effect reported across all studies was temporary hair loss in the 10 Gy cohort.
Capacity. A six fraction course over three weeks, or a five fraction course over one week, is short per patient. The population is not. According to the Alzheimer’s Association 2025 Facts and Figures report, 7.2 million Americans aged 65 and older live with Alzheimer’s dementia. Even a small eligible fraction would exceed the open linac time in most regions. Physics and dosimetry coverage, which can be delivered remotely, would be the first constraint to ease. Therapist coverage at the machine would be the second.
Compliance and billing. No CPT or coverage pathway exists for radiation as an Alzheimer’s treatment outside a clinical trial. Any delivery today belongs inside an IRB approved protocol with trial based billing. Leadership should not plan revenue on this indication until a definitive trial reads out and payers respond.
Limits of the evidence
The honest summary is that LDRT for Alzheimer’s is safe at the doses tested and unproven for benefit. Five points keep it there.
- Sample size. Fewer than 40 treated patients appear across all published human studies as of October 2026. No study was powered to detect a cognitive effect.
- Blinding. Only the Korean phase II trial used a sham arm, and it blinded patients but not assessors. The first double blind trial starts in late 2026.
- Dose. Published regimens differ by a factor of forty, from 24 cGy to 10 Gy total. The field has not settled on a dose, a fraction size, or a schedule.
- Follow up. The longest reported follow up is 12 months. Alzheimer’s progresses over years, and radiation effects on normal brain can appear late.
- Comparators. Anti amyloid antibodies now exist as approved disease modifying therapy. Any future LDRT trial will need to position itself against or alongside them, and none of the current trials does.
A sixth point is commercial rather than scientific. One of the two new trials uses a proprietary device rather than a linac, so a positive result there would not transfer directly to existing departments.
What Team Net Medical recommends
Leadership should assign ownership now and defer investment until the controlled trials report. Ranked by risk, the actions are as follows.
| Priority | Action | Owner | Timeline |
|---|---|---|---|
| 1 | Name one physician and one physicist to track NCT07863011, NCT07564700, and the final NCT05635968 results, with a written summary to leadership twice a year | Department chair | Start now; first summary within 90 days |
| 2 | Ask the physics team to document current low monitor unit output verification and identify what a sub 10 cGy fraction would require | Chief physicist | Within 6 months |
| 3 | Open a conversation with neurology and nuclear medicine about an amyloid PET referral pathway, so the department is ready to join a trial rather than build one | Department chair with service line leadership | Within 12 months |
| 4 | Model linac and therapist capacity against a hypothetical non cancer population, so the capacity answer exists before anyone asks for it | Operations with Team Net Medical | Within 12 months |
| 5 | Hold any marketing, patient facing material, or revenue planning until a definitive trial reports and a coverage pathway exists | Executive leadership | Until further notice |
Team Net Medical can support items 2 and 4 directly through remote physics review and capacity modeling, and can help a department prepare to participate in a multicenter trial when one opens in the United States.
Sources
- Rogers CL et al. Low Dose Whole Brain Radiation Therapy for Alzheimer’s Dementia: Results From a Pilot Trial in Humans. IJROBP, 2023
- NeurologyLive. Low Dose Whole Brain Radiation Therapy Elicits Positive Results in Early Alzheimer Disease Dementia
- Kim BH et al. Low Dose Radiation Therapy in Alzheimer’s Disease: An Interim Analysis from a Multicenter Phase II Trial. Alzheimer’s & Dementia, 2025
- Chung WK et al. Evaluation of Low Dose Radiation Treatment Effects Using Conductivity, Diffusivity, and Brain Tissue Volumes in Mild Alzheimer’s Disease. Diagnostics, April 2026
- Goloborshcheva VV et al. Insights into the Impact of Low Dose Ionizing Radiation on Neurodegenerative Disease Progression in In Vivo Models. IJMS, April 2026
- NCT07863011. ReadyCure exploratory double blind trial, Korea
- NCT07564700. HOPE trial, Heinrich Heine University Düsseldorf
- Alzheimer’s Association. 2025 Alzheimer’s Disease Facts and Figures
About Team Net Medical
Team Net Medical supports radiation oncology programs across radiation oncologist, medical physics, dosimetry, and radiation therapist coverage in locum, hybrid, remote, and onsite models, alongside program assessments, compliance, and revenue integrity work, with reporting built to connect clinical capacity to financial performance.
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