Re: Radon in urine Part 2

[Les Fraley <les@lamar.ColoState.EDU>]

On Sun, 24 Nov 1996, Moroney, Roger W wrote:

> I have received many helpful replies to my original posting regarding
> the radon progeny in an urine sample. Based on them, I counted an empty
> vial from the same box of vials and did not find anything. I also
> counted another urine sample from the subject this past Fri which also
> came up clean.
> 
> The vials were recently received in our lab. There were stored in the
> original plastic wrapped container and had been opened about 5 days
> before the first problem. The screw caps are in a separate bag. One
> reply discussed static electricity, plastic vials and radon progeny.
> This may be a possible solution.
> 
> Several respondents inquired as to subtraction of environmental
> background from samples. Yes there was. I have not seen much of a
> problem in the past (which is not all that long) with radon progeny in
> either our gamma spect results or in the background counts. Certainly
> nothing like the recent urine sample. It seemed to me that it was not
> actually from the subject but having a lack of knowledge in this area I
> was not sure. I am running a new background count now (the current one
> is only a few months old). It has been raining a lot, the weather has
> turned cold and the heat is on. I suspect all of these items could cause
> a rise in the radon levels in our lab.
> 
> This was an interesting problem.
> Roger Moroney
> Radiation Specialist
> Mallinckrodt Nuclear Medicine
> wrmoroe@mkg.com
> 314.770.7457 voice & 7998 fax
> 
Roger,
  A couple of years ago, during the early part of a rain, a lab person 
came into the building and when they left the lab a few minutes later, 
they monitored their shoes with an alpha survey meter (we were working 
with 239-Pu at the time, very low levels) and they got something like 30+ 
alpha counts/min.  We made them remove their shoes which we kept.  The 
alpha counts decayed with the expected rate of 222-Rn progeny.  The only 
thing we could figure out was that the rain wash out dust with 222-Rn on 
it, and the person picked it up, as mud-like stuff? - as they walked to 
the building.
Les Fraley