Others, though, disagree, basing their views on scientific literature that supports continued use of the LNT model for radiation protection. The National Council on Radiation Protection and Measurements recently reaffirmed this viewpoint in May following a review of 29 public health studies on cancer rates among people exposed to low-dose radiation, including those affected by the U.S. World War II atomic bomb droppings in Japan, leak-prone Soviet nuclear installations, medical treatments, and other sources.

Findings from 20 of the studies fall in line with the principle that even low-dose exposures cause an increase in cancer rates, whereas most of the other studies were found to be inconclusive and one was deemed flawed.


Roy Shore, chief of research at the Radiation Effects Research Foundation, a joint project of the United States and Japan, and the chair of the review, said in an interview that those that claim a safe threshold does exist “would have to come up with some data. Certainly the evidence did not point that way,” reported the Associated Press.

Current EPA guidelines state that even exposures below 100 millisieverts – roughly equivalent to 25 chest X-rays or about 14 CT chest scans – slightly increases an individual's chances of developing cancer in the future, though a section was added in July emphasizing that the chance of incurring cancer from this was low.
“According to radiation safety experts, radiation exposures of ... 100 millisieverts usually result in no harmful health effects, because radiation below these levels is a minor contributor to our overall cancer risk,” says revised policy.

At the same time, the FDA broadly claims that a single CT scan with a dose of 100 millisieverts could potentially increase the risk of developing a fatal form of cancer in about 1 chance out of 2,000.

EPA spokesman John Konkus weighed in last Tuesday on the rule change, saying that proposal is focused on “increasing transparency on assumptions” around how the body reacts to different doses of dangerous substances, and that the agency “acknowledges uncertainty regarding health effects at low doses” and supports more research on that.

“The proposed regulation doesn’t talk about radiation or any particular chemicals. And as we indicated in our response, EPA’s policy is to continue to use the linear-no-threshold model for population-level radiation protection purposes, which would not, under the proposed regulation that has not been finalized, trigger any change in that policy,” he said, according to AP.

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