RE: I-131 therapy capsules

["North, David" <DNorth@Lifespan.org>]

There may not be an intellectually valid reason, but there is a practical
one: it is possible for some I-131 to find its way onto the vials containing
capsules or liquid during the manufacturing process. An impromptu survey
yesterday of ten plastic vials that had contained I-131 therapeutically
administered to patients revealed the following: two vials had contained
liquid, both were contaminated externally; eight vials had contained only
capsules, two were contaminated externally. In all cases the removable
quantity of I-131 was slight, but the I-131 photopeak at 364.5 keV was
positively identified on our Genie 2000 MCA. I would further venture that
most, if not all, of the capsule vials were internally contaminated as well.
When the routine post-administration assay of the "empty" vial is done, we
always see a few mCi of remaining activity. Perhaps that remainder is
adsorbed onto the little dessicant packet that accompanies the capsules, but
it's in there.

David L. North, Sc.M. DABR
Associate Physicist
Department of Medical Physics
Rhode Island Hospital
593 Eddy St.
Providence, RI 02903
ph: (401)444-5961
fax: (401)444-4446
dnorth@lifespan.org


> ----------
> From: 	carol marcus
> Reply To: 	radsafe@romulus.ehs.uiuc.edu
> Sent: 	Wednesday, April 19, 2000 15:52
> To: 	Multiple recipients of list
> Subject: 	Re: I-131 therapy capsules
> 
> At 02:17 PM 4/19/00 -0500, you wrote:
> >To all you nuc. med hospital types who previously used oral solution
> >I-131 but now use I-131 capsules for therapy doses - how have your
> >thyroid bioassay requirements (for personnel administering) changed (if
> >they have) and what are they currently?
> >
> >Thanks,
> >
> >D. Steva
> >University of Virgina
> >
> >************************************************************************
> >The RADSAFE Frequently Asked Questions list, archives and subscription
> >information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> >
> 
> 
> Dear Ms. Steva:
> 
> There is no intellectually valid reason to perform thyroid bioassays on
> any
> technologist or physician who administers NaI-131 in either capsule or
> liquid form.  All commercially available preparations are stabilized
> against
> volatility except for the CIS product, and that is stabilized by Syncor
> before dispensing.  So, unless you are making NaI-131 in your own reactor
> and using it for therapy, and I don't know anyone left in the USA who is,
> and you are not stabilizing it, it is senseless to perform a bioassay.
> About 10-12 years ago several nuclear pharmacists in different university
> laboratories independently measured the volatility of all liquid and
> capsule
> preparations.  Volatility was miniscule, and interestingly, higher for the
> capsules than the liquid.  Inquiries to California, Texas, Florida, and
> the
> NRC revealed not a single example of a thyroid bioassay beyond regulatory
> limits in workers who administered any of these commercially available
> products.  
> 
> These data were presented to NRC multiple times by me when I was on their
> ACMUI, to no avail for over a decade.
> Nonsensical as these bioassays are, it gives inspectors a box to check.
> If
> the NRC were truthful about "risk informed" requirements, it would have
> gotten rid of the bioassay requirements as soon as it was shown the data.
> 
> Some Agreement States are scientifically enlightened and actually use
> scientifically valid data.  At Harbor-UCLA Medical Center in California,
> we
> are not required to perform thyroid bioassays.
> 
> Ciao, Carol
> 
> Carol S. Marcus, Ph.D., M.D.
> Harbor-UCLA Research and Education Institute
> <csmarcus@ucla.edu>
> 
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> The RADSAFE Frequently Asked Questions list, archives and subscription
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