Re: LNT, SNT, or whatever

[Bernard L Cohen <blc+@pitt.edu>]

On Fri, 23 Feb 2001, Bjorn Cedervall wrote:

> >Linear is nice and simple as a theory - easy top work with.  It is also
> easy to test.  And - the test failed!
> ---
> No threshold has to my knowledge been seen on the level of point mutations, 
> chromosomal aberrations etc. The micronucleus assay gives a straight line 
> down to a level of about 2 mGy per cell generation. The resolution limit is 
> of course determined by statistics (it could probably be pressed down to 
> about 1 mGy/generation with "reasonable" costs). Specific chromosomal 
> aberrations are known to be associated with certain tumors. Knocked out Rb 
> functions (due to point mutations, non-disjunction, deletions etc) result in 
> tumors. There is more along this line.

	--You are ignoring the factors other than initating events that
affect the development of cancer and may be affected by radiation - like
stimulation of the immune system, stimulated production of repair enzymes,
etc. Initiating events occur very frequently due to non-radiation causes,
and cancers initiated by them may be suppressed by the above. That could
make the net effect of low level radiation non-linear or even hormetic. 

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