LNT prevails

Supporters of the linear-no threshold model of radiation risk got a big boost from the National Academy of Science in a report (BEIR VII Phase 2) released yesterday.

Personally, I'm not a fan of LNT. It's an overly conservative model and considering that every living organism on the planet evolved in a sea of terrestrial and cosmic background radiation, it just doesn't make much intuitive sense. The problem is that at low doses, the statistics just aren't there, and what is there is incredibly noisy. So trying to extract anything meaningful in terms of risk/adverse effect is stretching things pretty thin.

However, considering that regulatory agencies already develop recommendations and regulations based on LNT, I don't expect there to be much of an impact on the way us radiation people work.

From the NAS:

Low Levels of Ionizing Radiation May Cause Harm
June 29 -- A preponderance of scientific evidence shows that even low doses of ionizing radiation, such as gamma rays and X-rays, are likely to pose some risk of adverse health effects, says a new report from the National Research Council. In living organisms, such radiation can cause DNA damage that could eventually lead to cancers. The report provides a comprehensive assessment of these risks based on a review of the scientific literature from the past 15 years. It is the seventh in a series of assessments from the Research Council called the Biological Effects of Ionizing Radiation.

From the Report-in-Brief:

the current scientific evidence is consistent with the hypothesis that, at the low doses of interest in this report, there is a linear dose-response relationship between exposure to ionizing radiation and the development of solid cancers in humans. It is unlikely that there is a threshold below which cancers are not induced, but at low doses the number of radiation-induced cancers will be small. Other health effects (such as heart disease and stroke) occur at higher radiation doses, but additional data must be gathered before an assessment of any possible dose response can be made between low doses of radiation and non-cancer health effects. The report also concludes that with low dose or chronic exposures to low-LET irradiation, the risk of adverse heritable health effects to children conceived after their parents have been exposed is very small compared to baseline frequencies of genetic diseases in the population.