ALARA causes and reinforces excessive fear of low dose radiation
The current practice for controlling ionizing radiation exposures is ALARA – (As Low As Reasonably Achievable). This practice is based on acceptance of the 1950s vintage assertion that all exposure to radiation, down to a single low energy gamma ray, carries a greater than zero probability of causing a genetic mutation that might result in either a hereditary defect or cancer.
Some medical imaging professionals who use diagnostic tools employing radiation or radioactive materials believe that they should acknowledge and accept that patients have a legitimate reason to be concerned about radiation. By assuring the patient that they do everything they can to avoid exposures, they believe patients are reassured. ALARA means that their care provider is taking the smallest risk possible while still obtaining information needed to help them avoid even greater risks.
Other imaging professionals accept the evidence supporting their understanding that doses associated with proper medical imaging procedures are far below the doses that might cause harm. They believe that the policy of emphasizing ALARA principles contributes to patient concerns and may even cause some patients to avoid needed procedures.
In January, the journal Medical Physics published a Point/Counterpoint debate on this controversy with the following proposition.
Advocating for use of the ALARA principle in the context of medical imaging fails to recognize that the risk is hypothetical and so serves to reinforce patients’ fears of radiation.
Colin G. Orton Ph.D. Professor Emeritus, Wayne State University, provided the proposal and the discussion introduction. Jeffry A. Siegel, Ph.D. argued for the proposition. Cynthia H. McCollough, Ph.D. argued against the proposition. Both debaters provided brief opening statements and a single round of rebuttals responding to the other’s opening statement.
For the Point/Counterpoint section of Medical Physics, this is the standard stopping point. As a result of existing policy and technical limitations, the Medical Physics editor rejected follow-up contributions related to the published discussion.
According to correspondence made available to Atomic Insights, the journal editor recognizes that some discussions deserve a mechanism for continued engagement, additional points and further interaction with people who might not have been initially invited to provide their views. He even acknowledged that this topic is one that deserves additional exchanges, so he might revisit his rejection decision after making alterations to the current web site software.
While that journal is developing the technical capability to host such discussions, authors of the rejected letters decided that the Atomic Insights comment feature might provide an interim solution.
As a continuation of the excellent debate started by Drs Siegel and McCollough here are additional contributions.
J. J. Bevelacqua
Bevelacqua Resources
Dear Editor,
This correspondence addresses the Point/Counterpoint debate by Drs. Jeffry A. Siegel and Cynthia H. McCollough on the use of the ALARA principle in medical imaging.1 The as low as reasonably achievable (ALARA) principle is based upon the linear no-threshold hypothesis (LNTH) that assumes low doses of ionizing radiation are harmful and should be minimized. Using superficial arguments, LNTH/ALARA appears to be a beneficial philosophy, but upon examination of relevant data and experience, it accomplishes a result that is opposite to its intent2-6. In attempting to protect patients from an imagined detriment, the arguments fostered by Dr. McCollough limit the use and application of a vital diagnostic tool.
Dr. McCollough defends ALARA in medical imaging by extrapolating the observed carcinogenic effect of high-dose radiation to the low-dose range used in medical imaging. She notes, “current biological and epidemiological evidence cannot definitively prove that low doses of radiation are safe”. This statement inherently relies on the flawed LNTH and its ALARA derivative. As such, it fails to acknowledge studies observing a reduction of cancers following low-dose rate exposures7 and publications that illustrate significant flaws in the LNTH3,7,8.
As applied to medical imaging, Siegel1 and Siegel and coworkers2 succinctly outline the fallacy of the LNTH and its illegitimate ALARA progeny. These authors note that credible evidence of imaging-related carcinogenic risk at low absorbed dose (2 observe that the LNTH and associated ALARA concepts are fatally flawed and focus only on molecular damage while ignoring protective, organismal biologic responses. The societal harm caused by the LNTH and ALARA has been well documented1-8.
The LNTH also affects acceptance of the use of radiation and radioactive materials and causes the ALARA concept to create harm rather than the presumed benefit. These concepts create a world in which ALARA becomes A Law against Radiation Applications, and radiophobia is continually reinforced.
Radiophobia has inhibited research using low-dose radiation in the detection, prevention, and treatment of cancer and other diseases. Unwarranted fears caused by belief in the LNTH have also effectively inhibited research involving unique applications of radiation and radioactive materials. These applications include the use of low-dose radiation as a treatment protocol.
Patients have refused computed tomography scans and physicians are not prescribing these procedures because the LNTH/ALARA dogma has created concern for the subsequent radiation detriment. This fear could result in missed diagnoses because imaging doses are too low to produce adequate tissue resolution6.
LNTH/ALARA induced radiophobia promotes increased regulations of radiation and radioactive materials. The associated costs to implement compliance further dampen the expansion and use of radiation and radioactive materials. Regulations affect consumer, medical, industrial, healthcare, and research applications and result in significantly increased costs with very limited benefit.
Dr. Siegel provides a rational argument for rejecting the LNTH/ALARA fallacy. I hope that his arguments will cause professionals to challenge poor science and facilitate the use radiation and radioactive materials to benefit society.
REFERENCES
- Siegel JA, McCollough CH, Orton CG. Advocating for use of the ALARA principle in the context of medical imaging fails to recognize that the risk is hypothetical and so serves to reinforce patients’ fears of radiation. Medical Physics. 2016:n/a-n/a.
- Siegel JA, Pennington CW, Sacks B. Subjecting Radiologic Imaging to the Linear No-Threshold Hypothesis: A Non Sequitur of Non-Trivial Proportion. J Nucl Med 2017; 58:1–6.
- Doss M, Little MP, Orton CG. Point/Counterpoint: low-dose radiation is beneficial, not harmful. Med Phys. 2014; 41(7): 070601-1 – 070601-4.
- Calabrese EJ. On the origins of the linear no-threshold (LNT) dogma by means of untruths, artful dodges and blind faith. Environmental Research. 2015; 42: 432- 442.
- Bevelacqua JJ. Health Physics: Radiation-Generating Devices, Characteristics, and Hazards. Wiley-VCH, Weinheim (2016).
Cohen MD. Point: Should the ALARA Concept and Image Gently Campaign Be Terminated? Journal of the American College of Radiology 2016; 13(10): 1195-1198. - Doss M. COUNTERPOINT: should radiation dose from CT scans be a factor in patient care? No. Chest. 2015;147(4)874:877.
- Sacks B, Meyerson G, Siegel JA. Epidemiology without Biology: False Paradigms, Unfounded Assumptions, and Specious Statistics in Radiation Science (with Commentaries by Inge Schmitz-Feuerhake and Christopher Busby and a Reply by the Authors). Biological Theory. 2016;1-33.
Author: Bill Sacks, Ph.D., M.D.
Retired physicist and diagnostic radiologist
To the Editor: This is a comment on the recent Point/Counterpoint debate published online regarding use of the ALARA principle in medical imaging between the two medical physicists, Jeffry A. Siegel and Cynthia H. McCollough (https://doi.org/10.1002/mp.12012).
Dr. McCollough begins her Opening Statement by referring to the ICRP’s principles for medical radiation protection, but offers them as though they were “The fundamental principles” without questioning them. The two ICRP principles are justification and optimization: first, that the use of any ionizing radiation must confer medical benefit, and second, that the lowest dose necessary for diagnostic quality must be used.
The justification is unarguable, though it should refer not just to ionizing radiation, but to any medical procedure whatsoever. The ICRP’s optimization is not a “fundamental” principle, but rather one that is wholly based on the LNT assumption, which is precisely the point under debate.
The ICRP, as Dr. Siegel ably points out, bases its optimization principle on a falsehood, one that never had any justification, and furthermore one that sees mounting evidence against it and in favor of hormesis (benefit). It is simply not true, as McCollough asserts, that “it is just as difficult to prove hormesis as it is to prove carcinogenic risk.” This unjustified assertion can only be based on a profound ignorance, or dismissal, of the experimental and observational literature.
Even McCollough agrees that “credible evidence of imaging-related low-dose (< 100 mGy) carcinogenic risk is nonexistent.” Thus, the justification principle stands in stark contradiction to the optimization principle that is called for by the ICRP and endorsed by McCollough (despite her agreement that there is no evidence of risk). The former is based on a value judgment and is unarguably valid (in general) and the latter is based on a scientific matter of fact and is completely erroneous.
McCollough’s call for “maintaining the trust of our patients,” by showing them that we pay close attention to avoiding over-irradiating them or their children, is therefore precisely the wrong thing to do. Instead of accommodating to the public’s – and most medical practitioners’ – unwarranted fear of low-dose ionizing radiation, the only way to gain, let alone maintain, the trust of our patients is to disabuse them of this decades-old myth that low doses of radiation are harmful, that they contribute to causing cancer.
Accommodation to a myth that only reinforces radiophobia stands in stark contradiction to the need to appeal to scientific experimental and observational evidence and thereby, over time, disabuse the public and medical professionals of their fear.
The effort to inject into the public discussion the reality of the safety of low-dose radiation, and even its probable double benefit (both directly as a stimulus to enhanced immune surveillance and adaptive protection, and indirectly in the form of needed diagnostic information), as Siegel points out, should be our goal.
Optimizing the public’s awareness of scientific reality is the only justifiable approach for those of us who know that there is no evidential basis for radiophobia and growing evidence of the salutary direct effect of low-dose radiation, as well as its unarguable diagnostic benefit.
Mohan Doss
Diagnostic Imaging
Fox Chase Cancer Center
Dear Editor,
I am writing with reference to the Point/Counterpoint debate by Drs. Jeffry Siegel and Cynthia McCollough regarding the use of the ALARA (As Low As Reasonably Achievable) principle in medical imaging.1 The ALARA principle was established in radiation safety based on the linear no-threshold (LNT) model for radiation-induced cancers, in order to minimize the cancer risk from the use of radiation.
The LNT model is justified based on the assumption that DNA damage and mutations are caused by even very low levels of radiation and increased mutations would result in increased cancers, using the somatic mutation model of cancer. Both of these notions underlying the LNT model have turned out to be wrong.2 Whereas there would be an increase in DNA damage shortly after exposure to low-dose radiation (LDR, there would also be enhanced bodily defenses such as increased production of antioxidants and DNA repair enzymes, collectively referred to as adaptive protection.3
Because of the boosted defenses, there would be less of the naturally occurring DNA damage in the subsequent period, with the net result being reduced overall DNA damage and mutations following exposure to LDR.2 Also, there is plenty of evidence against the mutation model of cancer.2 Thus, since the two concepts underlying the LNT model are not valid, the model is not justifiable. Hence, the concept of ALARA, which is based on the LNT model, should not be used in medical imaging, considering that medical imaging involves LDR exposures only.
Dr. McCollough defends ALARA in medical imaging by referring to the well-known carcinogenic effect of high-dose radiation and then stating “current biological and epidemiological evidence cannot definitively prove that low doses of radiation are safe”. She then concludes that the precautionary principle must be invoked to deal with the uncertain risks of LDR. Her statement ignores the large number of studies that have shown reduction of cancers following LDR exposures4 and so the precautionary principle, which relates to dealing with uncertain risks, should not be applied to LDR.
Whereas there are many publications that appear to support the LNT model, careful scrutiny has shown that they have major flaws rendering their conclusions not trustworthy.4-6 In addition, the data generally recognized as the most important for estimating the health effects of radiation, the atomic bomb survivor data, are no longer consistent with the LNT model but consistent with the concept that low radiation doses reduce cancers.7
Dr. McCollough refers to the public perception of radiation as being bad and justifies ALARA to assuage the resultant public fears. The public perception of radiation is based on the misinformation that has been provided to them regarding the carcinogenicity of even the smallest amount of radiation based on the LNT model. The public needs to be informed about the observed cancer preventive effect of LDR to allay their concerns regarding the low radiation doses from diagnostic imaging.
Dr. McCollough expresses concerns that before the ALARA and Image Gently programs were initiated, some children were being imaged with higher adult doses. However, these were still low doses and would not have caused any harm to the children since the ultimate effect following such low radiation doses would be reduced DNA damage and mutations, after the effects of the adaptive protection are factored in.
Children have much stronger immune system and much lower cancer risk compared to adults. LDR would boost their immune system, reducing their cancer risk even further, based on the immune suppression model of cancer.2 Thus, the statement commonly made, that children are much more radiosensitive than adults, based on the atomic bomb survivor studies which involved high radiation doses, is not applicable to the low radiation doses involved in medical imaging. There was indeed no need to initiate the Image Gently program, and the program should be discontinued in view of its unjustifiability and the harm it has caused to patients in multiple ways, as described by Dr. Siegel.
Dr. McCollough states that the health effects of low doses of radiation are simply too small to demonstrate, quoting a publication from 19808 which based its conclusion on the LNT model, and extending the statement to hormetic effects. In doing so, she ignores the vast amount of literature that shows considerable reduction of cancers following LDR exposures.4 Considering the invalidity of the arguments of Dr. McCollough, there is neither justification nor need for ALARA in medical imaging.
References
- Siegel JA, McCollough CH, and Orton CG. Advocating for use of the ALARA principle in the context of medical imaging fails to recognize that the risk is hypothetical and so serves to reinforce patients’ fears of radiation. Medical Physics. 2016; doi:10.1002/mp.12012.
- Doss M. Changing the Paradigm of Cancer Screening, Prevention, and Treatment. Dose Response. 2016;14(4):1559325816680539.
- Feinendegen LE, Pollycove M, and Neumann RD, Hormesis by Low Dose Radiation Effects: Low-Dose Cancer Risk Modeling Must Recognize Up-Regulation of Protection, Therapeutic Nuclear Medicine, R.P. Baum, Editor. 2013, Springer.
- Doss M. COUNTERPOINT: should radiation dose from CT scans be a factor in patient care? No. Chest. 2015;147(4):874-7.
- Doss M, Little MP, and Orton CG. Point/Counterpoint: low-dose radiation is beneficial, not harmful. Med Phys. 2014;41(7):070601.
- Sacks B, Meyerson G, and Siegel JA. Epidemiology Without Biology: False Paradigms, Unfounded Assumptions, and Specious Statistics in Radiation Science (with Commentaries by Inge Schmitz-Feuerhake and Christopher Busby and a Reply by the Authors). Biological Theory. 2016;11(2):69-101.
- Doss M. Linear No-Threshold Model vs. Radiation Hormesis. Dose Response. 2013;11(4):480-497.
- Land CE. Estimating cancer risks from low doses of ionizing radiation. Science. 1980;209(4462):1197-203.
Your comments are welcome.
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A reminder: “Radiation and Reason” by Wade Allison. Low level ionizing radiation is harmless.
Rod – thanks as always for this post. I think that this is a another demonstration that a debate format is not the right thing for a discussion of radiation issues. The debate format assumes that there are only two positions available, and forces the discussion into complete polarization: there is only “for” or “against”. And there is a “winner” and a “loser”.
That is not what science is about. The science is about discovering the facts, not about winning a debate. The debate format gets in the way of the science.
Although I’m not a big fan of the LNT, I agree with Cynthia H. McCollough. LNT may be overestimating the damage but, due to the uncertainties of how damaging are low doses, we should follow the Precautionary Principle and asume it’s a credible hypotesis.
My personal opinion is that LNT will not be (dis)proved bellow 100 mSv while there is such partisan debate around nuclear power.
Greetings
@Pedro
Thank you for your opinion. I disagree with your characterization that the debate around nuclear power is “partisan.” My research has indicated that it is much more of a financial matter, with people who are interested in continuing to base our economy on inferior energy products deeply invested in attempting to maintain excessive fear about radiation.
A major part of the fear campaign is continuation of the myth that we just don’t know enough about the effects of radiation at very low doses. That myth is based on the supposedly extreme difficulty of precisely measuring the effects because they are so hard to detect.
Even when that was somewhat true in an era where biological sensing was relatively primitive, it never made any rational sense. If an effect is too small to measure, why worry about it, especially when there are so many measurable hazards associated with all competitive forms of energy production?
Rod,
I vote that we adopt a new standard for measuring radioactivity- The Fractional/multiple Banana scale. Then we could describe the danger of an accident like Fukashima as “injurious as eating 4.5 bananas a day” or whatever the actual number is. At least the public can understand that. Then the EPA and NRC restrictions on radiation allowed at a NPP would begin to look as senseless as they actually are.
I know that that is not very scientific, but we can all relate to it.
Pedro,
You assume that “playing it safe” with nuclear (only) will reduce public health risks overall, or at worst not cause any harm (other than possibly wasting a bit of money). This logic is flawed.
“Playing it (extremely) safe” in the nuclear field has rendered nuclear non-competitive with fossil power generation, whose negative health and environmental impacts are orders of magnitude larger. The result has been much less nuclear use, and more fossil fuel use, which in turn has resulted in a tremendous *increase* in risk and harm to the public. It has resulted in increased harm even if one assumed LNT was true. But if LNT was false, it is even more clear, and tragic. Due to LNT, and other things (baseless prejudice against nuclear by the public), we are actually choosing energy sources that DO cause tremendous harm over one (nuclear) that MIGHT cause a small amount of harm (if LNT is true).
So, I’m afraid it’s not that simple, i.e., just deciding to “play it safe” with this one industry, or form of pollution (radiation). For starters, you have to look at the big picture, and try to reduce overall risks, as opposed to just focusing on reducing risks from one industry. Secondly, with respect to questions like whether LNT is true, deciding to err in one direction is not simply “safe”. In general, erring in one direction is just as bad as erring in the other. I’m afraid that one has to get it right.
At a minimum, taking such a cautious attitude is indefensible as long as fossil fuels are allowed to pollute continuously despite the fact that we KNOW their pollution causes harm (and on a much greater scale). I’m not holding my breath for the time that fossil plants are required to fully sequester all of their wastes and pollution. Given that, we should ignore much smaller nuclear risks/impacts; certainly if there is only a (less than equal) chance that they are even real.
As Rod said in his last paragraph (and a mantra of mine): Too small to measure, too small to matter.
You’re probably right, though, that this will be an uphill political climb. NRC probably won’t cooperate, that’s for sure.
Thanks Rod & James for your kind replies.
Although I’ve read with attention the reports that Rod has made around the connections between the oil industry and the antinuclear movement, I don’t think he has demostrated that the relationship wasn’t stablished fairly (to protect oil industry interests). An old Greek proverb says “truth is truth, no matter who says it”. So, the oil industry may do a fair claim about radiation… Even if it protects its own interests.
The opposite is true, of course. Nuclear industry defenders can expose the LNT flaws. Because, yes, it hasn’t been proved bellow 100 mSv.
I agree with James that aplying those stricts limits ONLY to nuclear industry is quite unfair. And the worst of it is that nobody is telling people this. A few examples:
—Recently I saw an “investigator” claiming that the 1 mSv/year of contamination that the CSN (the Spanish NRC) has stablished as “safe” for Palomares incident is “not based in the public health”. Sorry? Does he tell the people the normal background radiation is around 1-10 mSv/year? Nope.
—I also recently discussed with an antinuclear guy that was (and still is) convinced that half of Honsu is contaminated “because exceeds the limit for nuclear waste”. I repeated him over an over that this limit ONLY applies to nuclear industry and that a lot of things surpass the limit (most of the ground, coffee, fertilisers, he himself got quite close…). But to no avail.
Could it be possible to set other limits? I don’t know. I feel comfortable knowing that we’re doing our best to protect people from radiation damage. But I set on fire when I see that those precautions are ill interpreted by some individuals.
Greetings
@Pedro
I’m not certain that you and I share the same definition of the word “fair.” The oil industry has a right to protect its interests and has a fair claim of providing an incredibly useful product. It ventures into “unfair” territory when it invents a hazard assertion about its competition out of thin air; there was never any evidence to support Muller’s claim that radiation caused damage all the way down to the lowest possible dose. In fact, he was in possession of contrary evidence BEFORE he insisted on the “no safe dose” assertion during his 1946 Nobel Prize speech.
He and his colleagues suppressed that evidence and then he spent another 10 years (1946-1956) using his credibility as a “Nobel laureate” pushing the rest of the radiation protection community to accept that “from a genetics point of view” there was no safe dose. He and his supporting foundation – the oil-soaked, but officially non-profit Rockefeller Foundation – finally achieved measurable success on June 13, 1956 with the following New York Times headline.
The oil industry also crosses into “unfair” practices when it hires green surrogates to fight against a competitor under the guise of “environmentalism.” If the oil industry wants to protect its interests fairly, it could simply explain why it believes its product is superior and why customers should buy it instead of other products that can accomplish similar tasks.
Hello Rod.
Thanks for your kind answer. I was thinking about the “Rockefeller connection” that you dennounced in this blog. Sorry, I had forgotten your post about the “Muller-Calabrese issue”.
I think you may have a point about the issue but the LNT has support from most of the scientific community, although it’s a hot question and you can find also supporters of LT, hormesis and biphasic model (as far as I know, the less credible of all). What we know for sure it that it’s difficult to detect a “little effect” from a “no effect”.
Thanks for your interesting reports.
Pedro
@Pedro
Actually, the biphasic response model is the one that has the most experimental evidence. It is not an effect that applies just to radiation, but to a large range of chemicals and even physical activities like breathing.
The support from the “scientific community” for the LNT isn’t strong, even in the reports like BEIR VII which is often held up as evidence of consensus. The words it uses are quite nuanced; in essence it is “accepted” because they did not admit the existence of any evidence that showed a positive benefit. If you ignore all of the data points that fall below zero, it’s possible to find a positive slope, even in a highly unordered and seemingly random set of data points.
Dear Rod.
Perhaps I wasn’t clear enough when I told I didn’t give much credit to the “biphasic model”. As I understand it, “biphasic model” states that the LNT underestimates the damage at low dose. Biphasic model it’s a quite odd statement, equivalent to saying that drinking 10 liters of wine in a single dinner will do less damage than drinking the same 10 liters of wine in 50 dinners. As far as I known it’s not even considered “scientific”.
For your words in this and previous posts, I understand you support the hormesis model, which has a growing support from data and the scientific community, but it’s (still?) not majoritarian.
Greetings
I see that Pedro has not read Wade Allison’s book. Please do that or his other web resources.
If Wade Allison (who promotes a book for sale) is so convincing, then why do ANS Health Physics society and others still support LNT as a practical approach? Surely not everyone is bought by big oil, or less informed than hormesis proponents?