Re: [cdn-nucl-l] Boreham, Scientists find low-dose radiation a benefit; Fw: Brenner/Hall paper on CT scans an hypothetical cancer risks

[Rod Adams <atomicrod@aol.com>]

During the NA-YGN/YMG workshop that preceded the ANS Winter 2007  
meeting, Commissioner Lyons of the NRC gave a talk that included a  
mention of the fact that recent studies had indicated that the  
average annual exposure to Americans had just about doubled due to  
the use of diagnostic medical procedures. He stated that the  
commission was trying to figure out how to handle that piece of news.  
During a different part of the talk, he also indicated that the  
Commission had no plans to discard the Linear No Threshold ASSUMPTION  
of radiation health effects.

The combination of those two thoughts concerned me enough so that I  
made sure my hand was the first one raised for a question. I wanted  
to know how the Commission planned to help Americans understand that  
they would be accepting a much higher level of risk by AVOIDING life  
saving medical diagnostic procedures than they would be by trying to  
take actions to keep their radiation exposures below a level that has  
already been shown to be essentially devoid of risk. I think I even  
managed to insert some words into the question that indicate my  
support of the well supported theory that low levels of radiation  
actually have healing benefits.

Commissioner Lyons agreed that there was cause for concern. However,  
he did not provide an answer on how the Commission could prevent this  
kind of idiotic interpretation of the conflicting bits of  
information. What I thought would happen is that people, especially  
those who do not understand much about numbers, risk, or science  
would make the following, risky interpretation of news reports:

"Medical procedures involving radiation have doubled the average  
American's annual radiation dose. All radiation doses carry a risk of  
cancer. Therefore, if I avoid a recommended medical procedure because  
it uses radiation, I will be lowering my risk of cancer."

We MUST stop this madness! We must challenge the LNT as a huge  
example of BAD science that can be fatal to people if used in  
decision making or regulations.

It is bad enough to add cost to nuclear power, but adding cost and  
risk to medicine is even worse.

I know at least 10 people personally who are alive today who would  
not be without medical use of radioisotopes, CT scans, and all of the  
other types of radiation using diagnostic procedures.

Rod

On Dec 3, 2007, at 10:36 PM, Jerry Cuttler wrote:

> Nice article ...
>
> http://www.thespec.com/article/290638
>
> Scientists find low-dose radiation a benefit
>
> Doug Boreham
>
> The Hamilton Spectator  (Dec 3, 2007)
>
> In a disturbing study published recently in the New England Journal  
> of Medicine, U.S. researchers claimed that 2 per cent of all  
> cancers in coming decades will be caused by routine diagnostic CT  
> (computed axial tomography) scans.
>
> (The report, by two researchers at Columbia University, said the  
> average American's total radiation exposure has nearly doubled  
> since 1980, largely because of CT scans. About 62 million CT scans  
> were done in the U.S. last year, up from three million in 1980.  
> More than four million were on children. CT scans use X-rays. MRI  
> and ultrasound procedures do not.)
>
> There are a number of biological issues that make the type of  
> estimation in the Columbia University report inappropriate.
>
> For decades, scientists have been trying to estimate cancer risk  
> associated with low-dose exposure by estimating the risk from very  
> high-dose exposure. The fact is, it is difficult to estimate risk  
> from high, acute exposures down to very low exposures without solid  
> scientific data to support the conclusions.
>
> Researchers at McMaster University, for instance, are involved in  
> studies focused on the actual biological risks associated with low-  
> and very low-dose exposures.
>
> There are many biological reasons why risk extrapolations from high  
> doses are not consistent with real risks at low doses.
>
> First, cancer risk estimates from high-dose exposures come from  
> epidemiological data from atomic bomb survivors. Radiation-induced  
> cancer risk in a war-torn population of Japanese people 62 years  
> ago is vastly different than cancer risk in North Americans today.
>
> It is known even today that cancer risks between the two  
> populations are not similar because of different genetic  
> backgrounds and environments, regardless of radiation exposure.  
> Adding radiation to the equation only compounds the difficulties of  
> comparing cancer risks between the two populations.
>
> Cancer risk increases when the doses are high and acute, whereas  
> most medical procedures use low dose, from which no increased  
> cancer risk was observed in the A-bomb survivors. Therefore  
> estimating cancer risk in a modern North American population  
> exposed to very low-dose radiation based on data from high-dose  
> exposures in A-bomb survivors is almost impossible.
>
> In cancer risk estimations, it is assumed that all doses of  
> radiation are risky and the risk is simply proportional to the  
> dose. However, there are hundreds of scientific publications to  
> show this is not the case.
>
> At low doses, biological response mechanisms can eliminate minor  
> damage caused by low-dose radiation and restore things back to  
> normal with no associated risk.
>
> At high doses, other mechanisms are used as an emergency defence  
> for survival but these systems tend to be error-prone and  
> consequently increase cancer risk.
>
> Overall, biological mechanisms responding to low doses are  
> different than those at high doses. Therefore, assuming the  
> biological risk is the same at all doses is biologically flawed.
>
> There are also hundreds of scientific reports that support the idea  
> that low- dose radiation is a necessary environmental agent  
> required for life. Our research at McMaster University has shown  
> that low doses can have beneficial effects to living organisms, and  
> a large research study is currently under way to test the idea that  
> low-dose CT scans actually reduce cancer risk.
>
> Studies that investigate risk based on total dose are questionable  
> if the total doses have been additive, like adding up the entire  
> dose from several CT scans, because evidence supporting the idea  
> that total risk is also additive is lacking. It's like taking a  
> bottle of medicine all at once (which can be harmful) as opposed to  
> taking small doses of it over a period of time (which can be  
> beneficial).
>
> If a radiation dose is spread out over a period of time (split or  
> fractionated), like multiple CT scans done over a period of time,  
> the biological consequences are known to be reduced because  
> allowing time between the exposures allows cellular repair  
> processes to eliminate the effects of the prior dose. So the risk  
> is not proportional to the total additive dose.
>
> Therefore assuming that the total additive dose from multiple CT  
> scans, which is the high total dose required to make the calculated  
> estimated cancer risk from A-bomb survivor data, has the  
> corresponding additive biological risk may not be accurate.
>
> Also, there are many published reports, other than those on A-bomb  
> survivors, in populations exposed to low doses of radiation  
> comparable to doses from CT scans, which show cancer mortality is  
> not increased at these doses.
>
> Based on actual biological scientific evidence, and not calculated  
> extrapolation, an opposite conclusion about CT cancer risk is  
> equally plausible. That is, cancer risk in North America may be  
> reduced by 2 per cent over the coming decades because of low-dose  
> medical CT exposures.
>
> Studies that warn of increased risk based on calculations from high- 
> dose extrapolation from any genotoxic agent should be viewed with  
> caution, considered hypothetical, and also potentially detrimental  
> since misinformation can sometimes cause undue harm.
>
> Doug Boreham is an associate professor in the department of medical  
> physics and applied radiation sciences in the McMaster University  
> Institute for Applied Radiation Sciences.
>
>
> ----- Original Message ----- From: Scott, Bobby
> To: howard long ; Jerry Cuttler ; Carmel Mothersill
> Cc: 2007.aapm@aapm.org
> Sent: Monday, December 03, 2007 6:10 PM
> Subject: FW: Brenner/Hall paper on CT scans an hypothetical cancer  
> risks
> -------------------------------------
>
> From: Scott, Bobby
> Sent: Monday, December 03, 2007 11:32 AM
> To: 'Metting, Noelle'; 'Cyndi Jones';  
> 'kooyoomjian.jack@epamail.epa.gov'; 'Classic, Kelly L.'; 'Dicarlo- 
> Cohen, Andrea (NIH/NIAID) [E]'; 'stoneh@mail.nih.gov';  
> 'edouple@nas.edu'; 'Hirsch, Roland';  
> 'david.thomassen@science.doe.gov';  
> 'kooyoomjian.jack@epamail.epa.gov'; 'Quill, Helen (NIH/NIAID) [E]';  
> 'Coleman, Norman (NIH/NCI) [E]'
> Cc: 'Pam.Sykes@flinders.edu.au'; 'Edouard Azzam'; 'brenda laster';  
> 'brenda.rodgers@ttu.edu'; Edward J. Calabrese; 'Ludwig E.  
> Feinendegen'; 'Dietrich Averbeck'; 'Georg Bauer'; Douglas Spitz;  
> Gayle E Woloschak ; 'hsducoff@uiuc.edu'; 'Eleanor A Blakely';  
> 'lynn.hlatky@tuffs.edu'; 'clsanders'; 'Lyndy Volker'; Galina V.  
> Zhuntova
> Subject: Brenner/Hall paper on CT scans an hypothetical cancer risks
>
> Dear Colleagues:
>
> You are probably aware of the media coverage of the new paper by  
> D.J. Brenner and E.J. Hall entitled "Computed Tomography - an  
> increasing source of radiation exposure" that was published in The  
> New England Journal of Medicine 357:2277-2284, 2007. Brenner and  
> Hall extrapolated from high-dose cancer data associated with the  
> atomic blasts that took place in Hiroshima and Nagasaki to low  
> doses of X-rays from CT scans in clinical settings in the United  
> States, via using the linear no-threshold (LNT) model. The atomic  
> detonations involve gamma rays, neutrons, blast propelled  
> projectiles, and thermal waves. The population response involved  
> combined injuries (wounds, thermal burns, neutron/gamma-ray induced  
> damage) and recovery in devastated cities.  Without adjusting for  
> such combined injuries, adverse environmental effects, differences  
> in genetic susceptibilities of the Japanese and U.S. populations,  
> and using hypothetical low-dose cancer risks, Brenner and Hall  
> calculate that in coming decades, 2 per cent of all cancers in the  
> U.S. will be caused by routine diagnostic  CT scans.
>
> Attached is an article published today in The Hamilton Spectator  
> that presents a different perspective on low-dose radiation risks  
> associated with CT scans. The article was written by Doug Boreham  
> of McMaster University and is entitled "Scientist find low-dose  
> radiation a benefit".  I thought you may like to know about the  
> article.
>
> Best wishes,
> Bobby R. Scott, Ph.D.
> Senior Scientist
> Lovelace Respiratory Research Institute
> 2425 Ridgecrest Drive SE
> Albuquerque, NM
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