[ RadSafe ] Radon Breath Analysis - Simplistic Approach

[Stabin, Michael]

This is exactly right, and was developed as well by Srivastava GK, et
al. (Health Phys. 50(2):217-221, 1986). They suggested the value of f to
be 0.84, but this value is probably most applicable to workers who have
been in mines for several years and thus chronically exposed for an
extended period. Others have suggested values closer to 0.6. Toohey et
al. (Health Phys. 44, Suppl. No. 1, pp 323-341, 1983) noted that "the
exhalation of radon increases by a factor of two and then returns to
'normal' in a period of 1-2 hr following a meal", so measurements might
be better made before work on a Monday but some time after a morning
meal. Environmental radon can significantly interfere with proper
measurements, and should be given some attention.


Mike

Michael G. Stabin, PhD, CHP
Assistant Professor of Radiology and Radiological Sciences 
Department of Radiology and Radiological Sciences 
Vanderbilt University 
1161 21st Avenue South
Nashville, TN 37232-2675 
Phone (615) 343-0068
Fax   (615) 322-3764
Pager (615) 835-5153
e-mail     michael.g.stabin at vanderbilt.edu 
internet   www.doseinfo-radar.com

 
-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of Falo, Gerald A Dr KADIX
Sent: Thursday, March 10, 2005 3:55 PM
To: radsafe at radlab.nl
Subject: [ 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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