Re: RADSAFE digest 1623

[Wes Van Pelt <VanPeltW@idt.net>]

Ron L. Kathren wrote:
> 
> Wes ---
> 
> As I recall, the NRC plot did not have dimensions, magnitudes, or any
> numbers attached to it, nor even a specified end point, and was merely
> illustrative, not meant to be precise or definitive.  To interpret otherwise
> seems to me to be a bit of a stretch.
> 
> Ron
> 
>  At 03:11 PM 12/3/97 -0600, Wes Van Pelt wrote:
> >Ron L. Kathren wrote:
> >
> > Acting on your suggestion, I checked the web site.  As you indicated, the
> > plot shows a positive risk at zero dose. This is not at all incorrect but is
> > actually the proper presentation.  For example, if a specific effect (eg
> > thyroid cancer) is selected as end point, there will be a natural incidence
> > in a theoretical unirradiated population.  This then is what the graph
> > depicts.  To do otherwise would be misleading, for it would imply that the
> > entire risk was radiation induced.
> >
> > Ron Kathren
> >
> >Whooooh Ron!
> >
> >That NRC graph shows radiation induced risk to be about 5 to 10 times
> >the "zero dose" risk. Any real dose, below an acutely fatal dose, would
> >produce only a VERY slight increase over the "zero dose" risk.  In other
> >works, that phony NRC graph should be MUCH flatter.
> >
> >Best regards,
> >Wes

Hi Ron,
Here is what we know (without stretching)
	the graph is linear (after all, it purports to show the LINEAR NT
model)
	The risk at zero dose is X
	The risk at the highest dose on the graph is about 8*X (roughly)
	The graph has a max dose of about 100 rem (because at doses higher than
about 500 rem, the cancer risk curve goes to zero because the acute risk
goes to 1.0)
	At 100 rem the radiation cancer risk is about 0.03
	At 0 rem the natural cancer risk is about 0.2
	Therefore, the total cancer risk at 100 rem should be 0.23
	The graph, however, shows a risk of about 8*X = 1.6 !!!!
	Therefore, the graph is much too steep.

I think this is not really a stretch, but based on known cancer risk
information.

Regards,
Wes

PS Did you know our bud Norm Cohen is officially retired, but will
continue at NYU as a non-salaried Professor.