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Re: incorporation measurements

Carol Marcus wrote:

"THERE ARE NO DATA INDICATING A
PROBLEM.  As nuclear medicine has been practiced in this country for 63
years, I think that that's enough time to construct a data base.  NONE EXISTS."


I would agree with Carol and add the following:  I have worked for a radio-
pharmaceutical MANUFACTURER for over 20 years, and the largest internal 
exposure we have seen in that time has been due to inhalation of airborne
Mo-99 particulates after a loss of negative pressure on a hot cell back in
the 80's.  The committed effective dose was about 1 mSv (100 mrem).

Yes, our production staff submit urine bioassays on a weekly basis, due to 
the high activity throughput (100s of GBq up to 100s of TBq per week, 
depending on radionuclide), but we could easily justify discontinuing them
due to the rarity and insignificance of intakes.

Finally, the intake limits on most radiopharmaceutical radionuclides are
so high that if there were any significant intake, the worker would detect
a problem during routine contamination frisking.

For a more rigorous approach to deciding when to require some kind of bioassay,
take a look at ANSI 13.14-1983, "Internal dosimetry programs for tritium
exposure- minimum requirements", which provides guidance on when to require
bioassays based on activity levels, degree of volatility, and containment
level.  You can use this same approach for other radionuclides if you 
adjust for radiotoxicity (e.g. the ratio of ALIs) and relative volatility.

Hope this helps.

John Laferriere, CHP
DuPont Pharmaceuticals Co.
Medical Imaging Division
john.r.laferriere@dupontpharma.com


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