[ RadSafe ] WG: AW: Gregoire 06 shows rad-induced cancer requires dose rateexceeding 10 cGy/day

[Rainer.Facius at dlr.de]

The remarks below  from Don Higson through another channel  may be
helpful in evaluating the Gregoire&Cleland paper.
 
Regards
 
Dr. Rainer Facius
German Aerospace Center
Institute of Aerospace Medicine
Linder Hoehe
51147 Koeln
GERMANY
Voice: +49 2203 601 3147 or 3150
FAX:   +49 2203 61970
 

________________________________

Von: Don Higson [mailto:higsond at bigpond.net.au] 
Gesendet: Dienstag, 5. September 2006 13:05
An: Muckerheide; Facius, Rainer; Jodi.Strzelczyk at uchsc.edu
Cc: "Ruth Sponsler"
Betreff: Re: AW: Gregoire 06 shows rad-induced cancer requires dose
rateexceeding 10 cGy/day


Thanks for your help folks. I am going to discuss this paper with a few
of my colleagues.
 
My first reaction is that it might just possibly be the most important
reanalysis of radiation effects data ever written. Certainly, in my
view, it presents a potentially important new approach to this subject.
Clearly, much more data (and organ specific data) are needed to develop
the potential of this approach, and the situation is probably much more
complicated than the paper suggests. However, the authors are pointing
in an interesting new direction.
 
As the authors themselves say, their criteria for data selection rule
out a lot of data. This is fair enough when proposing a new approach,
provided the criteria are fair. The authors don't mention that some of
the data that have been ruled out are medical exposures related to
specific cancer sites (e.g. the North American studies of breast cancer
incidence related to fluoroscopy, at ~10mSv per examination).
 
In the context of the study, the 'threshold' is the transition from
biopositve to bionegative effects. It is not not NOT a step change from
zero effect to harm. For those who accept that there is such a
transition, it occurs at somewhere around 100 mSv for adult animals and
humans. Hence, 146 mSv/d is a reasonable level to find the threshold on
Figure 2, bearing in mind that all the data (at this level) are from
acute exposures that are probably single exposures.
 
The implication of the report is that an exposure to X mSv causes the
same risk, whether it is acute, protracted, intermittent or chronic,
provided X is the dose incurred during one day - but bear in mind that
all the acute exposures are to high doses and all the chronic exposures
are to low daily doses.
 
Don