The Mistaken Birth and Adoption of the Linear Non-Threshold (LNT) Model: An Abridged Version

As these GEITP pages have discussed a number of times, the detective work of Ed Calabrese has uncovered, and expanded upon, one of the top deceptions of all time: the purported Linear No-Threshold (LNT) Model, based on incomplete and dishonest scientific data. Thus, the LNT Model has been used for at least six decades –– costing the taxpayers of Western Society countries billions of dollars to construct data based on fundamental errors in the original basic research. This has led to risk assessment policy that is fundamentally flawed, and has been so, since the 1950s.

In 1927, Hermann Joseph Muller incorrectly asserted that he had used x-rays to induce “gene” mutations in the fruit fly, Drosophila melanogaster. Although his original experiments were flawed and unverified, this interpretation was well received and widely accepted by the scientific community. In fact, Muller proceeded to win the 1946 Nobel Prize in Physiology or Medicine for his so-called “breakthrough” research finding. Both the 1930 “Proportionality Rule” of Muller, and the 1935 “LNT Single-Hit dose–response model” of Timofeeff-Ressovsky and colleagues, were offspring to Muller’s misguided conception of x-ray-induced “gene mutations”. Critics from the genetics community –– including Lewis J. Stadler, Barbara McClintock, and others –– argued convincingly that Muller’s idea lacked scientific proof and could be explained alternatively by mechanisms involving gross chromosomal deletions and aberrations, rather than mutations within specific genes.

Responding to such criticisms, Muller quickly conducted further research to support the accuracy of his conclusions on x-ray-induced “gene” mutations –– specifically that mutational responses were cumulative (i.e. that the total dose — and not dose rate — was important), irreversible, and linear with respect to dose. However, more experimentally rigorous studies were performed under the oversight of the Manhattan Project and produced results that seriously challenged Muller’s concept of “total dose”. Unfortunately, influential leaders of the U.S. radiation and genetics communities, including Curt Stern and Muller, chose to misrepresent and thereby marginalize the more carefully performed studies. The LNT Model was subsequently recommended by the U.S. National Academy of Sciences, the Biological Effects of Atomic Radiation I (BEAR I), the Genetics Panel in 1956, and subsequent adoption by regulatory agencies worldwide. The attached article summarizes substantial recent historical revelations of this history, which should profoundly challenge the standard and widely acceptable history of cancer risk assessment, showing multiple significant scientific errors and incorrect interpretations, mixed with deliberate misrepresentation of the scientific record by a subset of leading ideologically motivated radiation geneticists. These novel historical findings demonstrate that the scientific foundations of the LNT Single-Hit Model were seriously flawed, from the beginning, and should not have been adopted for cancer risk assessment.

Dose-Response: An International Journal Oct-Dec 2o17; pp 1–3

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