RE: I-131 Bioassay, Requirements vs Recommendations

["Dunn, Wes" <WDunn@intiso.com>]

The revised 10 CFR 20 (and equivalent State regulations) requires the
licensee to assess internal dose if the worker is likely to exceed 10%
of the annual limit.  This is the same as the dosimetry requirement.
Hence, all licensees must bioassay all workers (or otherwise determine
the uptake) OR document an evaluation that the worker is not likely to
exceed the 10% limit.  In other words, the licensee must be able to
demonstrate that the worker doesn't need a bioassay.

To take the egregious example, a licensee who only uses sealed sources
can state that sealed sources are designed to prevent any release of
contamination and so no uptake is likely.  Furthermore, routine leak
tests confirm containment.  A similar analysis can be performed for
I-131 bioassays based on survey, use and/or previous bioassay data.

Wes 

Wesley M. Dunn, CHP, Director, Environmental Health & Safety
International Isotopes, Inc.
3100 Jim Christal Road
Denton, Texas  76207
Wdunn@intiso.com <mailto:Wdunn@intiso.com>
Corporate Website:  http://www.intiso.com
940-484-9492; 940-484-0877 (fax)


	-----Original Message-----
	From:	VERNIG.PETER@FORUM.VA.GOV
[SMTP:VERNIG.PETER@FORUM.VA.GOV]
	Sent:	Wednesday, October 07, 1998 1:40 PM
	To:	Multiple recipients of list
	Subject:	I-131 Bioassay, Requirements vs Recommendations

	So how do people feel about thyroid bioassay?  On one hand we
will likely
	have no requirement and on the other guidance requiring more
bioassays be
	done.  Oh, I forgot typically we're seeing single digit to maybe
a twenty
	nanocuries [0.001-0.02 uCi] on the bioassays for the high doses.
	 
	
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