THE HORMESIS THEORY
THE HORMESIS THEORY
The science of radiation is dominated by a paradigm based on a supposedly ¨sound observation¨ known as the linear no-threshold (LNT) hypothesis, that states that all ionizing radiation is harmful no matter how low the dose or the dose rate.
The LNT hypothesis is based on the incorrect use of mathematics and statistics in a way that was designed to confirm a prioiri conclusions. It is considered a partial failure also because it ignores the biological response of the organism.
The apparent validity of these studies is based on a defective experiment design and/or the misleading inference taken from weak statistical data. By contrast, the investigative studies in biology demonstrate the existence of hormesis by radiation, that suggests that low doses of radiation are beneficial for cells and organisms. (Figure 1).
The LNT model has sufficient proof in high dosages, but the linear form found at high doses was extrapolated to the low dose regions with much less scientific evidence. Many experiments have demonstrated data discrepancies when this extrapolation is applied to low doses.
For example, the study ¨Evidence for Adaptive Response in a Molecular Epidemiological Study of the Inhabitants of a High Background-radiation Area of Yangjiang, China¨ demonstrated that the death-rate for cancer in high background-radiation areas in China was less than in the control area, which suggests a possible adaptive response in areas with high background radiation levels.
The scientific community is still divided about the premise of hormesis provoked by radiation, with new literature being published regularly. The International Commission on Radiological Protection (ICRP) recommends the use of the linear no-threshold (LNT) model when planning radiological protection. This model establishes that the probability of induced cancer and any hereditary effects increase linearly with the dosage. As a result, all of the radiation exposure should be justified and have sufficient protection standards to ensure that the exposures are maintained below certain dosage limitations.
There exists a firm basis for the hormesis hypothesis, both biophysical and evolutionary, but the experimental evidence has yet to change official policies on this subject. The use of the LNT model has important ramifications for radiological protection and for human health in general, therefore it is important to resolve this issue.
The publishers of medical literature now admit that perhaps half of the scientific literature could be incorrect. The science of radiation falls in this category. The belief in LNT influences radiology practice, radiation regulation policies and popular culture via the media. The result is massive radiophobia and damaging consequences, that include the forced relocation of populations near nuclear powerplant accidents and renouncing imaging studies that are medically necessary.
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Su S, Zhou S, Wen C, Zou J, Zhang D, Geng J, Yang M, Liu M, Li L, Wen W. Evidence for Adaptive Response in a Molecular Epidemiological Study of the Inhabitants of a High Background-radiation Area of Yangjiang, China. Health Phys. 2018 Aug;115(2):227-234. doi: 10.1097/HP.0000000000000860. PubMed PMID: 29957687.
Sacks B, Siegel JA. Preserving the Anti-Scientific Linear No-Threshold Myth: Authority, Agnosticism, Transparency, and the Standard of Care. Dose Response. 2017 Jul 14;15(3):1559325817717839. doi: 10.1177/1559325817717839. eCollection 2017 Jul-Sep. PubMed PMID: 28814947; PubMed Central PMCID: PMC5548321.
Cardarelli JJ 2nd, Ulsh BA. It Is Time to Move Beyond the Linear No-Threshold Theory for Low-Dose Radiation Protection. Dose Response. 2018 Jul1;16(3):1559325818779651. doi: 10.1177/1559325818779651. eCollection 2018 Jul-Sep. PubMed PMID: 30013457; PubMed Central PMCID: PMC6043938.