Re: radon - documentation of exposure histories for Iowa study

[RuthWeiner@AOL.COM]

In a message dated 1/15/02 9:03:05 PM Mountain Standard Time, bcradsafers@HOTMAIL.COM writes:



> Do you agree that irreversible DNA damage can occur due to ionizing 
>
> radiation exposure?
>
>
> BTW: The most sensitive studies for induction of chromosomal aberrations 
>
> (micronuclei, Cs-137) show an absolutely straight line down to 2.3 mGy if I 
>
> recall correctly. The same seems to be true for point mutations in somatic 
>
> cells with increasing age.


What is "irreversible" DNA damage?  DNA repair also occurs at the molecular levels.


Moreover, cell damage does not translate linearly to organism damage, or even to organ damage.  Cells die every day.  Cells are killed in a variety of ways  (when I had hip surgery, plenty of cells were killed and damaged!)  That does not mean that the organism suffers permanent damage, or that the cell damage necessarily even propagates.  


 The LNT may well be an accurate representation of cell damage.  However, if the LNT were an accurate representation of radiation damage to an organism,  everyone would have some cancer, if only because of the natural body burden of radioactivity.  Moreover, every epidemiologic study would confirm this.   


Finally, cancer induction might in fact be linearly proportional to radiation exposure, but that does not necessarily imply a threshold.  It's the threshold question we are arguing.  Incidentally, the response to CO poisoning is linear, and has a very well known threshold.

Ruth Weiner, Ph. D.

ruthweiner@aol.com