Editor’s note: The following article is the preface to Ralph Thomas's paper given at the 2006 J. Newell Stannard Lecture Series in Sacramento, California. Our thanks to Dr. Thomas for providing us with links to the full text of his paper and slide presentation.
At past J. Newell Stannard Lecture Series some speakers have informally offered broad assessments of the progress that the science of radiological protection has made over the past fifty years and concluded it to be disappointing. To many these views may seem surprising, and indeed there appear to be arguments to the contrary. About five years ago the author wrote, “What deeply troubles me is that as a profession we have snatched defeat from the jaws of victory. After a wonderfully successful 30 years in which radiation exposures have, in general, steadily declined, we are left with a situation in which airline personnel are among those workers experiencing the highest estimated radiation exposures--and that due to natural radiation to boot. When I began my career in 1948 such an outcome would have been regarded as a triumph!” (R.H. Thomas 2000). Why, when there is a successful history of improving radiological protection, do several scientists express this winter of discontent? What is the nature of this unease?
In his notes to a lecture entitled “Internal Emitters-–Are We in the Know?" at the Twelfth Stannard Lecture Series, Bill Bair commented our “knowledge is inadequate to resolve current and future health issues” (Bair 2004)--this after nearly 50 years of experience. In his lecture notes Bair’s list of “unknowns” and “knowns” in radiological protection is helpful and revealing.
At the eleventh meeting in 2003 Bob Thomas bemoaned the very conservative choice of the dose rate effectiveness factor (DREF) when extrapolating from high to low dose rates in estimating risk from external photon exposure. In his opinion more suitable data were available for low dose, low dose-rate human exposures (R.G. Thomas 2003, NAS 1980).
In 2005 the author pleaded that the concepts and quantities of radiological protection quantities, and models derived from these concepts, should be defined with greater rigor than at the present time (R.H. Thomas 2005).
Neither has this “discontent” been limited to Stannard Lecturers nor is it new. Others have been critical for some time and on many fronts. Seven years ago no less a scientist than Harald Rossi commented, “During the past two decades the concepts of radiation protection and the applicable physical quantities have drifted into what may be regarded as chaos” (Rossi 1999; the underline is the author’s). More recently, the BEIR VII (Phase 2) report of the (US) National Academy of Sciences has drawn fire from some quarters--particularly on the issue of risk assessment at low doses and dose rates. Tubania and Aurengo (2005) have compared its conclusions with those of the equivalent French report: “[In contrast with the conclusions of] . . . the French Academies’ report, the BEIR VII report . . . concludes that the linear no-threshold relationship (LNT) should be used for assessing the carcinogenic risks of low or very low doses (whereas the French report determines the opposite). Since both reports rely to a large extent on the same data, the causes of this disagreement need to be investigated.” In a letter to the President of the National Academy of Sciences a senior official of the US Department of Energy expressed disappointment that BEIR VII did not discuss " . . . new and exciting biological research (that) has been published demonstrating that cells in tissues respond very differently to radiation than isolated cells in culture and that cellular responses to low doses of radiation are very different from responses to high doses of radiation . . . Biological mechanisms are now known to exist . . . to repair the damaged cells, and to suppress tumorigenisis” (Orbach 2005). Some have even dismissed BEIR VII as “bad science.” Rockwell (2006) asserts, “Only one of BEIR VII’s more than 700 pages directly discusses the subject of the report; 'How does a living organism respond to low-dose radiation?’”
There can be no doubt that the last fifty years has accumulated much information. Is the “Winter of Discontent” then a debate about differentiating between information, knowledge, and wisdom?
Bair, W. J. 2004. “Internal Emitters: Are We in the Know?” Twelfth Annual J. Newell Stannard Lecture Series, unpublished lecture notes, Sierra Nevada and Northern California Chapters of the Health Physics Society (http://hps1.org/chapters/snv/BAIR.pdf).
National Academy of Sciences (NAS). 1980. The Effects on Populations of Exposure to Low Levels of Ionizing Radiations: 1980. Committee on the Biological Effects of Ionizing Radiations (BEIR) III. Washington D.C.: National Academy Press.
Orbach, R. 2005. Cited by R. H. Thomas in “LNT Once Again.” Health Physics News, 33(12):7.
Rockwell, T. 2006. “Bad Science in Service of a Bad Hypothesis.” Health Physics News, 34(2):9-10.
Rossi, H. H. 1999. “Risk from Less than 10 Millisievert.” Radiation Protection Dosimetry, 83(4):277-279.
Thomas, R.G. 2003. “Why Have We Made the Population of the World Afraid of the Words ‘Radiation’ and ‘Nuclear’?” Eleventh Annual J. Newell Stannard Lecture Series, unpublished lecture notes, Sierra Nevada and Northern California Chapters of the Health Physics Society.
Thomas, R. H. 2000. “In Flight Radiation - The Right to Know.” Health Physics News, 28(13).
Thomas, R. H. 2005. “Rigour Within Uncertainty - an Unfinished Quest: ICRP and High-LET Radiations.” Thirteenth Annual J. Newell Stannard Lecture Series, unpublished lecture notes, Sierra Nevada and Northern California Chapters of the Health Physics Society (http://www.nea.fr/html/science/egsaatif/R-Thomas-Stannard-LectureR2.pdf).
Tubania, M. and Aurengo, A. 2005. “Dose-Effect Relationship and Estimation of the Carcinogenic Effects of Low Doses of Ionizing Radiation.” International Journal of Low Radiation, 2(3/4):134-151.
1 A corruption of “Women are wiser than men because they know less and understand more,” from The Crock of Gold (1912), chapter 2, by James Stephens (1882-1950).