The LNT Hypothesis: Ethical Travesties

Many thanks to Rod Adams for posting the transcript of this talk by: Margaret N. Maxey, Ph.D., Professor, Biomedical Engineering, College of Engineering, The University of Texas at Austin. Excerpts:

(…) Slowly but inexorably, radiation scientists are recognizing that the LNT hypothesis – at one time administratively useful in regulating radiation exposures during the infancy of radiation science — has in its maturity become scientifically illegitimate and ethically indefensible. In his book, Has Radiation Protection Become a Health Hazard? Gunnar Walinder, a Swedish radiobiologist, states unequivocally: “The linear, no-threshold hypothesis is one of the greatest scientific scandals of modern times.” Dr. Walinder’s bold statement is indicative of a significant sea-change among radiation experts in their assessment of the validity of using the LNT hypothesis as a basis for setting standards in radiation protection.

Among prominent experts, Leonard Sagan now observes that the LNT model is based on “politics and social concerns,” not science. Nobel Laureate Rosalyn Yalow writes that, “the literature and media overestimate radiation damage even if the overall effect does not differ from zero.” Sohei Kondo at Osaka, Japan’s Kinki University has conducted research into atomic bomb survivors which shows slight decreases in cancer deaths among those exposed to low doses — suggesting that radiation-induced precancerous cells undergo self-killing or apoptosis which prevents later development of a cancer. An emerging consensus concludes that current regulations for radiation exposure are not only “based on quicksand,” but have become pernicious obstacles to the ethical goal they purport to achieve: public health protection.

Radiation protection standards enacted by regulatory agencies have reflected ethical concerns based on two presuppositions:

(1) that the linear, zero-threshold hypothesis derives from scientific data in radiobiology that are virtually conclusive; and

(2) that it is “morally better” for health protection to assume that any radiation exposure, no matter how small, has some harmful effect which can and ought to be prevented.

These presuppositions have been reinforced by a popular unscientific belief that industrial man since World War II has introduced into the biosphere enormous quantities of synthetic toxic substances contaminating an otherwise benign natural world. These include “unnatural” radiation sources as well as huge quantities of “sinister” chemicals having no natural equivalents. Hence, official policy has enshrined a quasi-dogma: it is “morally prudent” to assume that “even the most minute dose, even a single molecule, may trigger a lethal change in a cell that will cause it to multiply malignantly.”


Ethical Travesties: Fear of radiation has proved to be far more detrimental to public health than radiation itself. No actual deaths of U.S. citizens have been attributed to accidental releases of radiation from reactors. But fear of radiation has proved fatal: (1) fear of bearing a “nuclear mutant” led 100,000 European women to choose unnecessary abortions after Chernobyl; (2) thousands of people avoid life-saving medical procedures such as mammograms or radiotherapy because they involve radiation; (3) regulatory roadblocks preventing management of harmless low-level wastes are causing many hospitals to shut down radiomedical treatment centers; (4) thousands of deaths from pathogens infecting seafood, eggs, beef and poultry could be prevented by irradiating food. Moreover billions of dollars have already been spent on trivial radiation risks based on grotesque scenarios about (1) single atoms destined to migrate through miles of desert soil to contaminate a potential water source in some distant future, or (2) measurable radon producing sick buildings which require costly remediation or destruction. Fear endangers human health.

Because the LNT model is deeply entrenched in standard-setting procedures of UNSCEAR, BEIR, ICRP and NCRP (UBIN), their bureaucracies have neither cited, discussed, nor refuted the data and theory contradicting the LNT model. Eventually, politicizing and prostituting scientific principles will erode not only the credibility of scientists, but also public confidence in regulatory institutions. Risk-tradeoff analysis is an ethically necessary replacement for the regulatory vested interests now dominating bureaucratic incentives to “keep the hazard alive” — namely, empire building, legalized plunder, research funding, sales of instruments, and indispensible services to a fearful public. An obsession with hypothetical health effects from but one technology siphons attention away from widespread harms claiming the lives of human beings daily.

Read the whole thing »

4 thoughts on “The LNT Hypothesis: Ethical Travesties

  1. I notice that not ONE BIT OF EVIDENCE was offered to discount the LNT theory. That is funny. LNT is as solid as evolution, the Big Bang, and many other scientific theories. Of course, one can always cherry-pick authority figures who disagree with the consensus. That’s what biology deniers do, vaccine deniers do, global warming deniers do, etc.

    Welcome to that wonderful club of science deniers.

  2. @ Bob,

    From all of your post I get the impression that you feel that ‘linear no threshold’ has been unfairly maligned for causing fear of radiation and blamed for the failures in the industry when in fact the theory is not the problem. You aren’t anti-nuclear, you just don’t think LNT is wrong or a problem.

    You criticized the poster for not providing references.

    Please enlighten me with some researched and published papers that do more than support the theory of ‘linear no threshold’ with more theory. A paper that shows a link between low doses (say less than 5 rem a year) and increased cancer rates would be great. This theory has been around for a long time, the tools to test it exist, surely after 50 some years it is surprising that we still call it the LNT THEORY.

    Also, does it really make you a science denier to challenge a theory; I thought that was kind of the point of science. So in addition to the author of this paper, the French Academy of Sciences, the Health Physics Society, and the American Nuclear Society, let me throw the following authors onto the pile of science deniers.

    Also lets count it as my first offering as to a researched scientific paper that shows something other than a theory in support of a theory. Of course I am clearly cherry picking.

    Ross S.

  3. Your impressions are correct. I get the impression you don’t understand that a theory is not a hypothesis. A theory is the best explanation to address a large number of tested hypotheses. You can’t “prove” a theory. You can disprove it or you can collect more and more evidence which supports it. LNT has never been disproven and all the evidence supports it.

    LNT is based on the observance of cancer versus dose. See here for more discussion:

    The study you linked to is at the bottom of the evidence pyramid. There are plenty of non-linearities at the cellular level, that’s not the point. The point is the overall manifestation of those non-linearities is best represented by LNT at the organism level.

    Also note that in your link the dose response is actually linear. At 0.1 Gy they got 64 RIF/Gy or 6.4 RIF, and at 2 Gy they got 15 RIF/Gy or 30 RIF. If you plot total dose versus total RIF it is linear.

    So, that study gives us some insight on the slope of the LNT graph, but it supports LNT, since we already realize that with less total dose there is less cancer risk. The study provides part of the physical mechansims underlying that.

  4. @ Bob,
    Ok I asked to be educated and I was clearly misapplying the concept of a hypothesis and a theory, so I thank you for correcting me.

    I also did not intend to suggest that the article I linked was a theory breaker; it was just an example of the kind of investigation I am interested in.

    My understanding of LNT is that it is a theory that was put in place because nothing better was available, it was largely assumed to be conservative, and something was needed to allow regulations to be established.

    I have also been lead to believe that the theory assumes that since high levels of exposure have been shown to cause cancer and that the assumed mechanism is damage to key parts of a cell’s dna that the incidence of cancer is simply a statistical probability and that is independent of the level of exposure.

    However as the link you sent me to points out, cancer is a much more complicated topic than it was assumed to be at the time of the theory’s adoption. It is a continuous process with multiple factors. Our cells dna is continuously being damaged from a variety of sources, many of which are far more prolific than the damage caused by exposure to low levels of radiation.

    It seems to me that the more we learn about cancer the more difficult it is to accept the concept that one lucky (or unluky depending on your reference point) beta particle can damage you in a manner that will result in your acquiring cancer.

    I apologize for being inflammatory in my previous post, it was unnecessary.

    Ross S.

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