[ RadSafe ] Fwd: French Academie des Sciences

[Richard L. Hess]

Ruth Weiner asked me to pass this along to the list as she is 
currently not subscribed.

Remember, Ruth is not reading RadSafe currently, so if you have any 
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From: RuthWeiner at aol.com
Date: Sat, 4 Mar 2006 18:38:24 EST
Subject: French Academie des Sciences

The Academies of Science and Medicine of France have issued a joint 
report, available on the web, that seems to me to refuteonce and for 
all the use of the linear non-threshold theory (LNT) as a method of 
predicting cancer risk at small (low) doses of ionizing radiation, 
and of predicting cancers in a population by "micro-doses to 
mega-populations."  The joint report is also found in M. Tubiana and 
A Aurengo, International Journal of Low Radiation v.2, 2005, pp. 1-19.

Some choice quotes from the report:

"...it is highly unlikely [because of very small risks] that putative 
carcinogenic risks could be established for such doses [< 100 mSv] 
through case control studies or the follow-up of cohorts, even for 
several hundred thousands of subjects.  The power of such 
epidemiological studies would not be sufficient..."

"A linearity observed in a study pooling together tumors of all 
types, occurring at all ages, could be only the consequence of the 
heterogeneity of the data.  It is not legitimate to use an empirical 
relationship for assessing the carcinogenic effect of low doses." 
[emphasis mine; Bill Field take note]

"...the use of LNT in the low dose or dose rate range is not 
consistent with current radiobiological knowledge; in particular the 
changes in cellular defense mechanisms...with dose and dose rate 
raise questions about its validity for evaluating the risks of a few 
dozen mSv." [emphasis mine; a few dozen mSv is a few rem]

" the use of a linear no-threshold relationship is not justified for 
assessing by extrapolation the risk of low doses from observations 
made for doses from 0.2 to 5 Sv since this extrapolation relies on 
the concept of constant carcinogenic effect per unit dose, which is 
inconsistent with radiobiological data."

Looks like Jim Muckerheide has been vindicated!  I can remember 
pointing out the extrapolation to my students a quarter of a century 
ago, and noting that extrapolation is always dicey.

The report is well-documented. It doesn't pool data, it's not a 
mega-study, or ecological study, or whatever, it cites different 
researches that have elicited similar phenomena.

All the best.

Ruth

Ruth F. Weiner, Ph. D.
ruthweiner at aol.com