Re: ICRP/NCRP Risk Factor Use

[Fritz Seiler <faseiler@nmia.com>]

Michael S Ford wrote:

> Question for the group:
>
> Given a risk factor of 4 E-2 fatal cancers per Sv and a collective dose
> of 1 Sv for a particular group, how is the resulting 4 E-2 fatal cancer
> risk interpreted?
>
> 4 E-2 fatal cancer risk for each person in the group OR
> 4 fatal cancers per 100 persons in the group, 40 per 1000, etc.?
>
> I had read previously -- ICRP and NCRP -- that the fatal cancer risk
> values only applied to populations not to individuals, but ICRP 26
> para 60 talks about *individuals* specifically.
>
> Thanks in advance for any information you may provide!
> v/r
> Michael
> *************************
> Michael S. Ford, CHP
> Radiation Safety Department
> Battelle Pantex
> Amarillo, TX
> 806.477.5727 phone
> 806.477.4198 fax
> mford@pantex.com
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Hi Michael,

I know that that is what the books and papers say, one going this way
and the other going that way.  As Joe Alvarez and I will show in an
upcoming paper, that chaos results from a lack of problem definition.
Basically, using the statistical information from the fit to the
experimental
data, the risk values with a linear model are the same, but the errors are
not. For the average person in an statistical ensemble, the error is given
by the standard error of the fitted mean.  For a particular individual in
the same ensemble, the error is given by the standard deviation of the
fitted value which is much larger, as it should be.  There is of course
quite a bit more to it, but that - for the moment - is the ball park.

Best regards

Fritz

*************************

Fritz A. Seiler, Ph.D.
Principal
Sigma Five Associates
P.O. Box 14006
Albuquerque, NM 87191-4006
Tel.    505-323-7848
Fax.    505-293-3911
e-mail: faseiler@nmia.com

**************************


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