[ RadSafe ] ERR query: the exact form of LNT

[garyi at trinityphysics.com]

Hi Dan,

When I asked about low background incidence, I was trying to guess the reason you said:
 
> For common cancers such as skin cancer in Caucasians or other neoplastic
> growths, such as thyroid abnormalities, it is necessary to use the exact
> form.

I am out of coffee here, so please forgive me if I'm being slow.

-Gary

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On 14 Jan 2008 at 13:06, Strom, Daniel J wrote:

Subject:	RE: [ RadSafe ] ERR query: the exact form of LNT
Date sent:	Mon, 14 Jan 2008 13:06:29 -0800
From:	"Strom, Daniel J" <strom at pnl.gov>
To:	<garyi at trinityphysics.com>, <radsafe at radlab.nl>


This equationis valid for common or rarebackground cancers. Its high dose behavior 
asymptotically approaches a probability of 1 at very high doses. For acute whole-body 
irradiation, that is, of course, nonsense, since everyone would die ofone or anotheracute 
radiation syndrome. However, for protracted partial body irradiation, such as the bone 
surfaces of radium dial painters, it's sensible. 

In a more complete versionof theequation that includes a threshold,P also includes 
background cancer (incidence or mortality or whatever the risk is): 

P(n' > 0 | b, k, D, D_0) = 1 - EXP(-{k[D - D_0] + b}) 

where 
n' is the total number of tumors in an individual, both radiogenic and nonradiogenic 
b is the background incidence;the probability of an individual contracting this kind of cancer 
in the absence of radiation exposure is= EXP(-b) 
k is the probability per unit dose 
D is the dose 
D_0 is a threshold dose 

-Dan Strom 
The opinions expressed above, if any, are mine alone and have not been reviewed or 
approved by Battelle, the Pacific Northwest National Laboratory, or the U.S. Department of 
Energy.
Daniel J. Strom, Ph.D., CHP
Energy and Environment Directorate, Pacific Northwest National Laboratory
Mail Stop K3-56, PO BOX 999, Richland, Washington 99352-0999 USA
Overnight: Battelle for the U.S. DOE, 790 6th St., Richland WA 99354 ATTN: Dan Strom K3-
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From: garyi at trinityphysics.com [mailto:garyi at trinityphysics.com]
Sent: Monday, January 14, 2008 12:46 PM
To: radsafe at radlab.nl; Strom, Daniel J
Cc: Strom, Daniel J
Subject: Re: [ RadSafe ] ERR query: the exact form of LNT
So you are saying that the kD approximation is only good for a given cancer type if the 
background probability is low - is that it? 

-Gary Isenhower 


Regards,
Gary Isenhower, M.S.
713-690-3020