(by nobody from nospam.not)
Wed Jun 9 20:32:44 EST 2010
Dr Engelbert Buxbaum <engelbert_buxbaum from hotmail.com> wrote in
news:MPG.26798da4dca3943798968f from News.Individual.DE:
> In article <4c46dc22-1694-45ea-ab11-
> a441674e057a from x21g2000yqa.googlegroups.com>, nick.theodorakis from gmail.com
>> On Jun 8, 10:12 am, "Allan Jones" <allan.jo... from gmx.de> wrote:
>> > Hi!
>> > There is currently a lot of radiation work going on in our lab and
>> > i am always worried about people contaminating stuff with small
>> > amounts of isotopes the geiger counter does not detect very well
>> > (ie tritium, 14c, 35s).
>> > Now I have looked into the definition of annual limit on intake and
>> > so on and am slightly confused. The ALI values seem extermely high,
>> > so does this mean the amounts (a couple of µCi) we use are not
>> > particularly dangerous?
>> > I do not assume anything is contaminated, but am a worrysome person
>> > and some of the people here seem quite relaxed concerning
>> > radioactivity. I guess however that back in their days its use was
>> > much more common.
>> > What do you think?
>> As a point of comparison, I once had a medical imaging test in which
>> I was injected with 5 mCi (yes, that's milli) of radioactive
>> thallium. When I got back to lab, they said, ha ha, let's see if
>> you're radioactive, and held a geiger counter up to my chest. If
>> course, I made the geiger counter chatter, at which point it seemed
>> they all backed away and said, "oh." They kept me away from the x-ray
>> film for a couple of weeks.
> A colleague of mine had a thyroid scan with Tc, and consequently
> blackened out his dosimeter. Created quite a stir with the safety
> guys, until the cause was established to be "not work-related". When
> he entered the lab, he could make the Geiger-counter needle wrap
> around its stop from several meters away.
> A couple of years ago a disgrunteled scientist poored 10 mCi of 32-P
> into the coffee urn in the common room at a US university. Widely
> published in scientific magazines at the time, but none of the exposed
> people suffered any ill effect.
> PET-scans are done with some 200 mCi (sic!) of 18-F (or at least were
> some 20 years ago, when I looked into it). Actual treatment of cancers
> is yet a completely different game.
> So follow normal safety precautions (ALARA principle), but don't worry
> too much.
Yes, A colleague revealed a now discontinued practice. This was >35
years ago. We used P32 phosphate, and stored it in a galss tube in the
freezer compartment of the fridge next to his desk. He hardly ever wore
the badge, since he wasn't using radioactivity <smile>. Harvard
radiation safety came in a panic, since the Xrays excited by the P32
electrons from the aluminum around the freezer compartment had blackened
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