[ RadSafe ] formula for cancer risk from radiation

howard long hflong at pacbell.net
Thu Jan 10 13:35:06 CST 2008

I don't understand how that equation can be correct, if there is LESS risk of cancer with supplemental 
low dose, slow dose rate radiation (hormesis).   
With that formula, do I understand that R (cancer risk) must always be MORE than R(0) 
(no added exposure), with any additional exposure [1+  ]? 
That is not true, if SOME added exposure LESSENS the risk of cancer, 
hormesis, as in Cameron's NSWS analysis, Taiwan apt data of Luan, etc, etc.

Alternatively, how about R = R(0) +- S (adjusted),  
 changing the part that made risk with supplemental exposure always more than 1?
How about S being the supplemental exposure in Gray (with you making mathematical adjustments 
to decrease risk  until ~20 cGy, then increase risk) ?

Even then,
How factor in slow rate, the different effect  over a year vs all at once?
How factor individual variation (like weight)?
How factor different effect on the same individual at different times (like when malnourished)?

Oversimplification misleads: 
1, Global warming models omit water vapor (far more important than CO2).
2, Medical ttreatment is dictated by politicians (regardless of an individual patient's problem with compliance). 
3, Nuclear power is lost with over-regulation (graphed by Ted Rockwell in his book).

Why give regulators another tool to tyrannize? 

Howard Long MD MPH

----- Original Message ----
From: Bernard L. Cohen <blc+ at pitt.edu>
To: RadiatSafety <radsafe at radlab.nl>
Sent: Thursday, January 10, 2008 9:59:24 AM
Subject: [ RadSafe ] query

Can someone help me on this question -- please reply to  blc at pitt.edu.
    If rhe risk of cancer, R, is expressed as
                            R = R(0) [ 1 + k D ]
where R(0) is the risk with no exposure, D is the dose in Sv, and k is a 
constant, what is the excess relative risk, ERR. I thought it would be 
ERR = k. In that case, a finding that ERR = 1.0 / Sv would mean that the 
risk is 2R(0) for an exposure of 1.0 Sv,        3 R(0) for an exposure 
of  2.0 Sv,  4R(0) for a dose of  3.0 Sv, etc. But this is hard to 
believe in a paper I am trying to understand. Any help on this would be 

Bernard L. Cohen
Physics Dept., University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245  Fax: (412)624-9163
e-mail: blc at pitt.edu  web site: http://www.phyast.pitt.edu/~blc

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