Re[2]: Nonlinear alphas

[te_hui@ccmail.pnl.gov]

     Correct me if I am wrong, but if the probability of not killing a cell 
     is p, then it would be difficult to convince me that the probability 
     of N alpha not killing the cell is N x p.  Shouldn't the probability 
     of surviving the alpha hits goes down instead of up?
     
     Edmond Hui
     PNNL


______________________________ Reply Separator _________________________________
Subject: Re: Nonlinear alphas
Author:  blc+@pitt.edu at -SMTPlink
Date:    8/1/96 9:30 AM


        If the principal mechanism for cell killing is passage of a
single alpha particle, the probability for a cell to be killed must be 
linearly proportional to dose. If a single alpha particle has a
probability of not killing a cell = p and a probability of causing a cancer 
if the cell is not killed =q, the probability of it causing a cancer is
p x q. Then the probability of N alpha particles causing a cancer is 
N x p x q, which is proportional to N, and therefore linearly 
proportional to dose.
     
Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu
     
     
On Thu, 1 Aug 1996, David Scherer wrote:
     
> OK, it wasn't my last try.  Melissa is back in town and she tells me that
> the problem is using the word *From* as the first word in a paragraph.  She 
> says *To* will give similar results.  Thought you all might like to know.
>
> Dave
>
> >B. Cohen pointed out that LNT for radon exposure is based on linear
> extrapolation from miner studies, regardless whether the biological insult 
> is cell killing or something else.  I was simply suggesting one possible
> mechanism that could result in a difference from low LET radiation and
> result in different dose-response curves for the two types of radiation. 
If
> there is substantial cell killing with alpha radiation at low doses, but 
not
> with low LET radiation at low doses, there could be two competing outcomes 
> for alpha radiation, one carcinogenic and one not.  (As I said before, dead 
> cells do not become cancer.)  The combined response might be non-linear.
If
> there is litle or no cell killing with low LET, cancer induction might be 
> linear.
> >Dave Scherer
> >scherer@uiuc.edu
> >
>