Friday, February 28, 2014

An Open Letter to Advisory Bodies Regarding Low Dose Radiation Cancer Risk

An Open Letter to Advisory Bodies[†] Regarding Low Dose Radiation Cancer Risk
Dear Colleagues,
The linear no-threshold (LNT) model was adopted worldwide for radiation safety purposes in the 1950s following the recommendations of the various international and national advisory bodies [1]. The decision to use a linear model was based on the observation of linear dependence of increased mutations in drosophila melanogaster subjected to high dose radiation, and linear dependence of increased leukemias in atomic bomb survivors exposed to high dose radiation.  In spite of the considerable amount of evidence available in the 1950s for the presence of a large threshold dose both for radiation-induced mutations [2] and for leukemias [3], the concept of zero threshold dose was adopted by the advisory bodies, violating basic scientific principles [4]. In addition, the consequent radiation safety policies recommended by the advisory bodies to keep the radiation doses as low as reasonably achievable prevented the study of radiation hormesis when it was proposed in 1980 [5]. Thus, these recommendations derailed the scientific method, since one unverified hypothesis was used to prevent the study of a competing hypothesis, stalling scientific progress in the field, and leaving the simple question whether the health effects of low dose radiation are beneficial or harmful unresolved even after intense study for many decades [6].
Though there has been a considerable amount of published evidence against the LNT model for radiation-induced cancers during the past several decades [5, 7-9], the LNT model continues to be widely promulgated. The atomic bomb survivor data, for example, have been used to support the LNT model of cancer risk in the influential BEIR VII report [10] and in many peer-reviewed publications, e.g. [11]. Even in the latest update to the atomic bomb survivor data [12], the authors have claimed that zero dose is the best estimate for a dose threshold for solid cancer mortality, apparently supporting the LNT model.  However, their dose-threshold analysis should be considered faulty since it restricted the possible functional forms of the dose-response relationship a priori. An analysis that used a more general functional form to fit the data has demonstrated that the presence of a dose threshold cannot be excluded [13].  In addition, a recent analysis of the atomic bomb survivor data using artificial neural networks has revealed the presence of a threshold dose that varied with organ, gender, etc. and the reduction of some cancers at low doses [14]
Another study used to justify carcinogenic concerns from low doses of radiation in the BEIR VII report and other publications [11] is the 15-country study of radiation workers [15, 16].  A re-analysis of the cancer mortality data of the Canadian nuclear workers [17] has resulted in a negation of the original conclusion of the entire 15‑country radiation worker study regarding cancer risks from low doses of radiation [18]. Also, a Bayesian analysis of the 15‑country study data has shown there is too much scatter in the data to make a definitive conclusion about the cancer risk from low doses of radiation, and that the dismissal of reduction in overall cancers in the radiation workers is unjustified [19, 20].
Thus, the main arguments in the BEIR VII report (and other publications) supporting the LNT model and increased cancer risks from low doses of radiation cannot be considered valid. Further, evidence supporting alternate (non-LNT) models and the beneficial effects of low doses of radiation (i.e. radiation hormesis) have been published since the time of the BEIR VII report   [21-26], and the evidence presented in these publications have not been challenged or repudiated in any peer-reviewed publication.  The advisory bodies have however ignored such publications without clearly stating why the evidence and arguments presented in such publications are invalid, and they continue to promote the use of the LNT model. 
The continuing recommendations supporting the use of the LNT model by the advisory bodies has had significant adverse societal implications, particularly with regard to radiation protection policies and public perception regarding radiation risk. For example, use of the LNT model has led to substantial casualties in real-life situations because of the ensuing fear of low doses of radiation among the general public, and the actions taken by governments when handling radiological emergencies, e.g. in Fukushima [27].  The use of the LNT model has also led to frivolous lawsuits when emergency responders were exposed to low levels of radiation near Fukushima [28].  The unwarranted concerns regarding low doses of radiation have discouraged study of the use of low dose radiation for the prevention and treatment of cancer, even though animal and human studies have demonstrated its positive potential [22]. Such concerns have also discouraged the study of low dose radiation for reducing neurodegenerative diseases for which presently there are no methods of prevention or control, even though animal  studies have shown promise [29, 30]. Finally, unwarranted concerns about the low doses of radiation used in medical imaging have led some patients to forego medically appropriate examinations, even when such exams are necessary for accurate diagnosis or therapeutic planning [31].  Thus, though the LNT model was touted as a conservative measure and a simplified, straightforward regulatory approach, its actual use has led to tremendous harm, and it is imperative that alternative paradigms for radiation safety are considered and adopted. 
Considering the overwhelming amount of data that supports the validity of low dose radiation adaptive protection [23] and the resultant invalidation of the LNT model, we urge you to recognize this publicly with a declaration and recommend to governments that they discontinue the use of the LNT model for radiation safety purposes, supplanting it with a threshold model.   
We would be happy to discuss this matter with you or provide additional information for your consideration. Thank you for your kind attention to this important issue.


Mohan Doss, Fox Chase Cancer Center, USA (
Wade Allison, Oxford University, UK
Allen Brodsky, Georgetown University, USA
Mervyn D. Cohen, Indiana University School of Medicine, USA
Jerry Cuttler, Cuttler & Associates, Canada
Ludwik Dobrzynski, National Center for Nuclear Research, Poland
Vincent J. Esposito, University of Pittsburgh, USA
Ludwig E. Feinendegen, Heinrich-Heine University, Germany
Krzysztof W. Fornalski, Polish Nuclear Society, Poland
Leo S. Gomez, Leo S. Gomez Consulting, USA 
Ed Hiserodt, Controls & Power, Inc, USA
Patricia Lewis, Free Enterprise Radon Health Mine, USA
Cynthia H. McCollough, Mayo Clinic, USA
Mark L. Miller, Sandia National Laboratories, USA
Steven S. Payne, National Nuclear Security Administration (Retired), 
                                                  Col USAF (Retired), USA
Charles W. Pennington, Executive Consultant, USA
Jeffrey S. Philbin, Sandia National Laboratories (Retired), USA
Chary Rangacharyulu, University of Saskatchewan, Canada
Charles L. Sanders, Korea Adv. Inst. of Science and Technology, 
                                                   S. Korea (Retired), USA
Bobby R. Scott, Lovelace Respiratory Research Institute, USA
Yehoshua Socol, Falcon Analytics, Israel
Michael G Stabin, Vanderbilt University, USA
Ruth F. Weiner, Former Member of the NRC Advisory Committee on 
                                              Nuclear Waste and Materials, USA

Note: All signers of this letter are members or associate members of SARI (Scientists for Accurate Radiation Information,  The above letter represents the professional opinions of the signers, and does not necessarily represent the views of their affiliated institutions.

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Note:  This Letter was e-mailed to the following advisory bodies on Feb 28, 2014:


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