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Re: Regulations from scratch
Kent Lambert wrote:
>biomedical research institutions, laboratories typically use fractions of a
>millicurie per experiment, with a few uses in the 1 - 10 mCi range (e.g.,
>initial aliquot preparation, labelling procedures), and rarely >10 mCi.
>As Kathi Elliott pointed out, with these activities of usually beta
>emitters, CONTAMINATION is the issue, not external exposure. Personal
>contamination is NOT going to be measured by a personal radiation
>monitoring device.
>No one has answered the question - At a hospital or university, where do
>you draw the line? Lab workers whose dose is zero, students whose dose is
>zero, secretaries whose dose is zero, visitors whose dose is zero?
Not only are the doses zero, but the beta emitters (e.g., P-32) will only
result in shallow dose equivalents to the skin and extremities. These
could, at very high doses, lead to deterministic (nonstochastic) effects.
However, they will not lead to stochastic effects, so there is, by
definition, no evidence from dosimetry records for the beta emitters
currently used in biomedical research that can be used for protection
against legal claims for such stochastic effects from deep dose equivalents.
This argument, of course, does not apply to the small number of users
working with mCi levels of I-125, a photon emitter.
Our procedures specify dosimetry (body and ring badges) for adults using
P-32 in well shielded experiments at levels of 10 mCi or more. While we
have eliminated about 15% of our badges this year with our new criteria,
many of our users have worn badges for many years and do not want to give
them up. I will not remove dosimetry from a person being monitored who
feels uncomfortable about losing his or her badges. Maybe I can keep
educating these researchers and gradually change their minds.
Frank E. Gallagher, III, CHP
Manager, Radiation Protection
and Radiation Safety Officer
Environmental Health & Safety Office Phone: (714) 824-6904
University of California Fax: (714) 824-8539
Irvine, CA 92697-2725 E-mail: fegallag@uci.edu
Note new zip code as of 7/1/96