RE: Stochastic vs. Non-Stochastic (from the Denver Thread)

["Crossley, Steven" <Steven.Crossley@health.wa.gov.au>]

 A thought on this topic...



Presumably you are suggesting that there would be some lower than

average (but above average background) threshold level for the

susceptible members of the population.  A group that always get cancer

from background levels would presumably have been removed by natural

selection.



If this were the case would evidence not appear for radiation workers,

in that we generally receive slightly above background doses and we

would presumably have just as high a proportion of radio-sensitive

persons amongst us as the general population.



Perhaps I'm over-simplifying



Steve Crossley

Perth, Australia



-----Original Message-----

From: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of Richard L. Hess

Sent: Tuesday, 21 December 2004 6:56 AM

To: james.g.barnes@att.net; RadSafe Bulletin Board

Subject: Re: Stochastic vs. Non-Stochastic (from the Denver Thread)



Hello, Jim,



Just to make sure I understand what you're saying, let me take it to a

different stimulus-response situation.



I know if I eat a LOT of peanut butter, I'll get fatter than I already

am and may die sooner.



However, if my son gets close to peanut butter he will have an allergic

reaction and may die without treatment.



In this case, we know of the allergic sensitivity and suspect peanut

butter is a serious potential trigger. We carry medicine for him at all

times.



Are you suggesting that there may be some sensitivity (like the food

allergy) or some lack of protective mechanism in some random group of

the population that makes them more sensitive to low level doses?



If so, it sounds like an interesting course of investigation to follow.



It also may extend to cancers in general, and not just radiation-induced

cancers, don't you think? Sounds like a lot more work on the human

genome might tease this out.



Cheers,



Richard

http://www.richardhess.com/tape/

Aurora, Ontario



At 09:19 PM 12/20/2004 +0000, james.g.barnes@att.net wrote:

>Dear all;

>

>There is a general opinion that there are stochastic and non-stochastic



>effects.  We say they are stochastic because the effects from exposure 

>appear to be statistically distributed in the population (we can't 

>predict who will experience effects, therefore we say it's a chance 

>event).  We say non-stochastic, because above a certain threshold, all 

>exposed persons appear to display the same set of symptoms.

>

>I've often considered this approach to have a gap in logic.  We are 

>saying that the chances of experiencing effects from low-doses is a

"chance"

>thing.  What if they are not; what if they are just as non-stochastic 

>as the effects at higher doses, but only to a sub-group of people who 

>are more inclined to display effects than others (probably through 

>genetic pre-disposition).  What if there were sub-groups who simply 

>could not physiologically handle radiation exposure as well as 

>everybody else, and that these "stochastic effects" are actually due to



>the stochastic distribution of these overly-sensitive individuals in an



>otherwise normal population.  The effects aren't stochastic; the 

>distribution of these sensitive individuals in the overall population

is the stochastic distribution.

>

>I have to think this alternative theory has been explored to some 

>degree?  Have any of you seen any discussion / research into this

concept?

>

>

>Jim Barnes

>





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