[ RadSafe ] Fwd: French Academie des Sciences

John Jacobus crispy_bird at yahoo.com
Mon Mar 6 15:28:34 CST 2006


If Ruth was subscribing to RadSafe, she would have
know that this is an old news story that appeared a
year ago.  I would hesitate to add that no changes
have been initiated thus far to relax any dosimetry
limits.

--- "Richard L. Hess" <lists at richardhess.com> wrote:

> 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 
> replies, please copy her as well as the list. Her
> email address is 
> <mailto:ruthweiner at aol.com>ruthweiner at aol.com and
> she is copied on 
> this message, so "reply-all" might work.
> 
>
============================================================
> 
> 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

+++++++++++++++++++
"It is not the job of public-affairs officers to alter, filter or 
adjust engineering or scientific material produced by NASA's technical 
staff."
MICHAEL D. GRIFFIN, NASA administrator.

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com

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