[ RadSafe ] ALARA
garyi at trinityphysics.com
garyi at trinityphysics.com
Mon Jun 23 10:44:51 CDT 2008
Please, could you clarify for me, what was the one valuable use of ALARA?
In reading your post it sounds like you say that keeping your doses low is the valuable part.
Pls let me know if I have misunderstood you.
On 23 Jun 2008 at 8:07, Conklin, Al (DOH) wrote:
I can tell you one very valuable use of the ALARA principle. We do a
lot of training here in Washington State of first and second
responders. Included in that training are a series of exercises we run
with radioactive materials, simulating detonated and undetonated dirty
bombs to show the responders how to approach a scene ,collect
evidence, do surveys, identify isotopes, etc. We use two cesium-137
calibrators, a variety of mixed calibration sources, occasionally some
natural sources, and Tc-99m, diluted in a gallon of water and sprayed
on debris to represent real contamination. The training is very
popular among the responders, but not so much among our political
non-technical upper management. In fact, most political entities
wouldn't allow this type of realism. The reason we can continue to do
it, is because we are very careful about keeping our doses ALARA. We
have RSOs who keep an eye on everyone and ask them to move if they
stand in a radiation field too long. We send in electronic dosimetry
if they don't have their own, and we record their doses. More often
than not, there are no measurable doses or they are very very small.
We keep that as evidence that we can do the training safely, and we
are allowed to continue. We do the work in an isolated bomb pit that
we can keep secure until the Tc-99m decays. We have a security company
guard the only entrance.
So, is ALARA stupid? From a purely dose perspective (saving a few
millirem) probably. But in a political atmosphere, it's not stupid at
all. Our trainees get a good and valuable experience, and practicing
ALARA doesn't hurt it at all. But, it does keep us in business
providing realism that the responders cannot get other places.
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of garyi at trinityphysics.com Sent: Friday, June 20, 2008 7:59 AM
To: radsafe at radlab.nl Subject: [ RadSafe ] ALARA
ALARA is just stupid. No doubt, people believe they are fulfulling
ALARA, but does anyone really do it? Or do they just reach a point
where they think, consciously or not, "Thats low enough" and stop
trying to reduce doses?
Consider bone densitometers. The operater sits unshielded at a
computer about 1 to 2 meters from the scanner. Is that ALARA? Yes,
the dose is very low, but ALARA does not care how low it is. It does
not matter. So if it is reasonable to shield a radiographic room or
fluoro room, why is it not reasonable to shield a DEXA unit the same
way, with about 1/16" lead and a shielded control barrier? If ALARA
is applied consistently, then perhaps all medical imaging rooms should
have 1/8" lead on all barriers, including floor and ceiling.
This is the bottom line. Do we get anything from ALARA that we could
not have just by writing clear regs? I'm sitting here trying to think
of anything at all, but I can't. I think its better to just tell
people what the limits are and what you expect them to do to comply
with those limits.
Somebody might say that ALARA results in lower doses to the
population. That's probably true, but you could have that just by
writing the dose limits lower in the regs. And this I think shows why
we have ALARA - because nobody in authority has the guts to say "This
is safe enough. This dose level is safe enough." There are too many
nuts who would froth at the mouth upon hearing those words applied to
If transportation risk was made ALARA, what would that look like? I
drive a lot in my business. That puts myself and anybody I pass on the
road at risk. People in houses along my route are at risk, and I bet
the risk is significantly higher than the risk to someone exposed to
0.1 cSv. How about that vacation you are planning? You mean you are
free, legally, to put all those innocent people at risk? Without even
warning them? OMYGOSH!
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