Low-dose ionizing radiation as a potential treatment for Alzheimer’s disease

Results of a small single-arm study in Canada suggest that low-dose ionizing radiation (LDIR) may be a promising therapy for Alzheimer’s disease (AD).

“In 2015, an AD patient in hospice was treated with ionizing radiation to her brain using repeated CT scans. Improvements in cognition, speech, movement, and appetite were so momentous that she was discharged from the hospice to a long-term care home. Based on this case, we conducted a pilot clinical trial to examine the effect of LDIR in severe AD,” explained the researchers. [Dose Response 2016;14:1-7; Dose Response 2017;15:1-2; Dose Response 2018;16:1-2]

Four residents of a long-term care facility with advanced dementia presumed to be primarily due to AD were enrolled in the study (age range, 81–90 years). All were clinically stable for ≥3 months. Qualitative data on patient communication and interaction with family members and caregivers were collected. In addition, three quantitative outcome measures were employed in this study to assess neurocognitive capacity, behavioural symptoms, and functional ability. [J Alzheimers Dis 2021;80:1119-1128]

All participants received three standard CT brain scans, each 14 days apart. “A brief exposure to LDIR damages biomolecules, including DNA, triggering the innate adaptive protection response, which not only remediates radiation-induced damage but also damage resulting from both endogenous and exogenous factors, such as natural oxidative ageing, pathogens, toxins, and injuries,” rationalized the researchers.

“LDIR therapy is controversial because it is generally accepted that ionizing radiation is a significant cause of DNA mutations and increases cancer risk. However, it is often overlooked that the rate of DNA damage due to natural background radiation is negligible compared with the rate of DNA alterations caused by the endogenous production of reactive oxygen species,” remarked the researchers. [Hum Exp Toxicol 2003;22:290-306]

While one patient did not experience any changes in the quantitative outcome measures and his family did not note any qualitative improvements, the qualitative data (descriptions, photos, and videos) from immediate relatives and caregivers suggested remarkable improvements in cognition and behaviour of the other three subjects.

In patients for whom positive changes were reported, improvements in cognition and behaviour were apparent within 1 day of treatment. Moreover, there was no evidence of deterioration following LDIR in any of the cases. “Surprisingly, there were few meaningful improvements on the three quantitative outcome measures,” noted the researchers.

“Although the degree of recovery was relatively small, a therapy consisting of multiple treatments at the optimal dose, separated by the optimal time interval, may produce a much greater and long-lasting recovery from symptoms of AD,” suggested the researchers.