Re: NUC MED THYROID BIOASSAY

["Mike Bohan" <mike.bohan@yale.edu>]

        Reply to:   RE>NUC MED THYROID BIOASSAYS 

The NRC used to give medical licensees a break on the bioassay requirements when
I-131 capsules were used.  However, they discovered "a" licensee who's staff
"apparently" believed that I-131 capsules were sealed sources.  They evidently
handled capsules and shipping shields without gloves, and as the story goes ...
appreciable thyroid uptakes occurred.   (Surprise!!!, Surprise???) 

I believe a paper in the Health Physics Journal described the incident which was
co-authored by someone from the NRC about 7 -10 years ago.  The important thing
to note was that these uptakes probably did not result from inhalation but from
sloppy handling practices.   However, using this incident as an example, the NRC
required that bioassays be performed even when capsules were used.  

We still use capsules in our program, but now require that Radiation Safety
personnel handle all capsules >30 mCi and administer them to the patient under
the authorized users direction.  This makes it easy to perform the bioassays
rather than try to chase down the authorized users 24 - 48 hrs later.  In ten
years (approx. 10 - 30 pts @ >50 mCi each/yr), we've never had a thyroid uptake
from capsules by occ. workers who handled them properly.

Mike Bohan
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><
Michael J. Bohan, RSO   |  e-mail: mike.bohan@yale.edu
Yale-New Haven Hospital |    Tele: (203) 785-2950
Radiological Physics    |     FAX: (203) 737-4252
20 York St. - WWW 204   |    As usual, everything I say may be plausibly
New Haven, CT    06504  |    denied at my employer's convenience ...
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--------------------------------------
Date: 21/06/96 1:43 PM
To: Mike Bohan
From: radsafe@romulus.ehs.uiuc.edu
Need some assistance ASAP on this subject.  We recognize that Regulatory
Guide 8.20 is quite helpful but we have lost our copy.  Is this document
available on the internet and if so where?  I have tried www.nrc.gov with no
luck.  We heard from one of the radioactive material suppliers that I-131
capsules are now considered volatile, is that correct?   We will greatly
appreciate any help you can give... Thanks  Eccsierra@aol.com