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ALARA/A single ionizing event
RADSAFERS,
Someone recently stated the following
"Why ALARA? Quite simply this: One ionizing event can cause a single
unrepaired double strand break, which may result in a fatal
malignancy."
If a single ionizing event is so potent, why aren't we all dead? Well,
I remember reading that we are struck by 15,000 quanta of radiation each
second. That computes to be 3.3E+13 quanta in a 70 year life time. It
is obvious that, if this number is correct, it is the probability of
each event resulting in a fatal outcome that is the important varible in
this equation. Obviously, that probability is very, very small, or else
you and I would not be around to read and write this email.
So, why ALARA? I do not see in these discussions that the proponents for
reconsidering the current LNT hypothesis and its application as
advocating the elimination of ALARA. As I read it, they only are
stating that there are data that do not fit the LNT hypothesis. I do
not see this as calling for an abandonment of controlling hazards and of
the application of good benefit analyses to optimized the use of
radiation. I do see a request for a reasonable application of ALARA.
What is reasonable? That appears to be the crux of the matter.
Depending upon the situation, saving an individual 100 mrem is a
worthwhile effort. Saving one individual 1 mrem or saving a collective
100 mrem at 1 mrem per person is not, even though the latter may look
good for the dose reduction statistician.
In conclustion, even if we were to eliminate the N from LNT, I do not
see why we as radiation protection professionals would be prevented from
exercising good judgment to optimize safety in the work environment.
As alway, just my own thoughts.
Kjell Johansen
Wisconsin Electric Power Company
Milwaukee, WI
kjell.johansen@wepco.com
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