[ RadSafe ] ALARA
garyi at trinityphysics.com
garyi at trinityphysics.com
Fri Jun 20 09:58:48 CDT 2008
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 radiation.
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!
-Gary Isenhower
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