AW: [ RadSafe ] Radon Breath Analysis - Simplistic Approach

[Franz Schönhofer]

Jerry and Mike,

I remember attempts a long time ago to measure the thorium body burden
by the exhaled thoron (Rn-220). I do not know what became of it,
probably it was not successful because I never heard about it again. 

Concerning radium-226 the situation seems to me not to be clear,
especially regarding "body burden". Since radium is a bone-seeker it is
incorporated into the bones. There is little chance in my opinion that
radon will emanate from bone tissue into adjacent tissue fast, then be
transported to the blood vessels, from there to the lung and then be
exhaled. A lot of disequilibria would be involved. Your approach rather
seems to indicate "soft tissue" burden. 

For radiation protection purposes the amount of Ra-226 in bones seems to
me to be of concern because of the daughter products and their possibly
damaging action on the bone marrow (similar to Sr-90/Y-90). 

I also support Mikes remark on the interference from environmental radon
or rather would emphasize this even more. Background radon levels are
not constant, especially if people work in factories using Ra-containing
material. Though I have no idea, how high the exhaled air-concentration
of "body burden" radon might be, I rather believe that it will be very
low compared to environmental concentrations and most probably not
discernable in the light of the error propagation law. 

We have recently finished a national standard on incorporation
measurements and dose calculations, but this was directed toward
isotopes used in nuclear medicine. Next Tuesday we will start a similar
project directed toward NORM and TENORM in industry. Since we have one
collegue in this working group who works in an industry where thorium is
of concern I might be able to post some more information about the above
mentioned thorium measurement method. Therefore I am interested in this
topic and ask you, to keep me informed. 

Best regards,

Franz

Franz Schoenhofer
PhD, MR iR
Habicherg. 31/7
A-1160 Vienna
AUSTRIA
phone -43-0699-1168-1319


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> -----Ursprüngliche Nachricht-----
> Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im
> Auftrag von Falo, Gerald A Dr KADIX
> Gesendet: Donnerstag, 10. März 2005 22:55
> An: radsafe at radlab.nl
> Betreff: [ RadSafe ] Radon Breath Analysis - Simplistic Approach
> 
> Hi all,
> 
> I was reviewing the 1994 Internal Dosimetry Summer School text and
some
> history and got to thinking about radon breath analysis to estimate
the
> Ra-226 body burden. My thoughts were basically as follows. Once the
> Ra-226 has come to equilibrium in the body, then the number of radon
> atoms produced in any given time interval T is the Ra-226 activity
> (A(Ra)) times T. Then if a fraction, f, escape "quickly" (neglecting
> radon decay as it transfers to the lungs) to the breath, the number of
> radon atoms exhaled over that time interval is f*A(Ra)*T. The
> concentration of radon (activity) exhaled is then the radon decay
> constant times the number of atoms exhaled divided by the total volume
> of air exhaled over time, T.  Finally, the Ra-226 body burden can be
> estimated:
> 
> Radium-226 body burden = (Measured radon concentration)*(Volume of
> exhaled air over time interval T)/f*(Rn-decay constant)*T.
> 
> I'm now wondering if I've oversimplified the issue and am missing some
> fundamental aspect of the analysis. Have I missed something? Any
replies
> can be to me directly, if you think that they would not be of interest
> to the list.
> 
> Thank you for your patience.
> 
> Jerry
> 
> ________________________________
> 
> The statements and opinions expressed herein are my responsibility; no
> one else (certainly not my employer) is responsible, but I still
reserve
> the right to make mistakes.
> 
> Check core temperature: yes./no? Yes! - Homer Simpson
> 
> Gerald A. Falo, Ph.D., CHP
> Kadix Systems
> U.S. Army Center for Health Promotion and Preventive Medicine - Health
> Physics Program
> jerry.falo at us.army.mil
> 410-436-4852
> 
> 
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