Low dose radiation suppresses cancer.
Note: Low dose in this case is defined as being below a threshold value of somewhere between 100 – 200 mSv depending on exposed organ.
That bold, conventional wisdom-challenging statement is supported by an incredibly important paper titled Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors published in the Journal of Radiation Research. It first appeared in an online version in December 2013.
Somehow, I missed the dramatic headlines about this paper and its paradigm-shattering conclusions; I’m sure they must have been all over the news media.
Maybe not. Perhaps the paper’s authors (Masao S. Sasaki, Akira Tachibana, and Shunichi Takeda) neglected to hire publicists, issue press releases and appear on syndicated talk shows.
Here is a quote from the Perspectives section of the paper.
Due largely to a limited statistical power at low doses in A-bomb survivors, cancer risk is often expediently correlated linearly with dose down to zero dose without threshold and expressed on a ‘per-Sv’ basis. The application of the ANN method developed here circumvents this difficulty and unequivocally demonstrates for the first time the presence of a threshold of excess relative risk in humans exposed to ionizing radiation. However, the threshold was fundamentally different from that of the canonical definition of zero effect until the dose reached a critical point, but instead it was manifested as a reduction of background cancer rate.
(Emphasis joyously added.)
Read that again.
Not only did the statistical analysis of existing data reveal the presence of a threshold, but it showed that doses below the threshold suppressed cancer. Instead of being “conservative” by assuming that there is no such thing as a safe dose of radiation, it is far more likely that 60 years worth of regulations and effort to keep doses As Low As Reasonably Achievable based on a consensus of accepting a linear, no-threshold dose response assumption has led to an uncountable number of extra cancers.
Those cancers might have been suppressed if only scientists and regulators had earlier access to modern data and statistical tools and learned that they should be prescribing health-enhancing moderate radiation doses all along.
PS: Here is the paper’s copyright statement:
© The Author 2013. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
That kind of copyright statement needs to be encouraged.