Re: radon - documentation of exposure histories for Iowa study

[e <blc+@PITT.EDU>]

On Wed, 16 Jan 2002, Bjorn Cedervall wrote:



> >4.  I BELIEVE the very notion of biological response to any given agent

> as linear, clear down to the smallest amount is ridiculous!  Especially

> when that agent is and always has been a part of nature.

> ---------------------

> 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.



	--Isn't it obvious that any effect which is directly caused by

radiation, with no other complications that can depend on radiation, must

follow LNT, at least if there is no more than one hit per cell

involved? The effect of a hit on one cell cannot depend on how many hits

there are on other far away cells. Presumably this applies to chromosome

aberrations if repair processes are not applicable or are not sensitive

to radiation.

	But for cancer death, there are many intervening steps that depend

on radiation -- production of repair enzymes, radiation stimulated

apoptosis, stimulation of the immune system, etc.



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