RE: I-131 therapy capsules

[carol marcus <csmarcus@ucla.edu>]

At 08:52 AM 4/21/00 -0500, you wrote:
>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
>> >
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>> 
>> 
>> 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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Dear Radsafers:

"Slight" (perhaps miniscule?) contamination is irrelevant.  It isn't enough
to cause a significant thyroid contamination in a worker who handles it,
because none has been found in the United States from stabilized material to
my knowledge.  Let us not be atom-hunting meter maids.  Thyroid bioassays
cost money, and if there is no legitimate basis in hazard for doing it, it
shouldn't be done.  Any legitimate and intelligent risk analysis would
agree, and Part 20 would also. It is perfectly reasonable for those handling
significant quantities of unstabilized material to be monitored, but
medicine has no leftover money for unproductive busywork. 

When patients given NaI-131 for hyperthyroidism or thyroid cancer go home,
there is much more contamination in the home than on the outside of the
vial.  The fact that even this larger amount is insignificant from a hazard
point of view is why we send these patients home.  If you look at the basis
for the 500 mrem Patient Discharge Rule, you'll see the analysis.

Ciao, Carol

Carol S. Marcus, Ph.D., M.D.
Harbor-UCLA Research and Education Institute
<csmarcus@ucla.edu> 

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