Re: KI and "Research" accidents

["Wesley M. Dunn" <WDUNN@brc1.tdh.state.tx.us>]

Naomi,

The ALI (Annual Limit of Intake) due to inhalation for I-125 is 60 uCi 
(Thyroid).  As such, a spill of "several hundred" uCi is highly 
unlikely to give an uptake in excess of the regulatory limits -- even 
if it were not mostly bound to the protein(s).  KI would not be 
recommended for such a situation.

So:

1)  Contact the RSO!  The RSO is supposed to be able to provide the
    proper guidance in a situation like this (and you should have 
    been provided proper training).

    That being said, a thyroid check 8-72 hours after the incident 
    would have verified any uptake of I-125 (assuming a working 
    thyroid).  The spill itself should have been neutralized for any 
    residual free iodine and cleaned up.  A Low-Energy Gamma probe 
    (such as a thin-crystal Na(I) probe) should have been used for 
    surveying the area (and people) to ensure proper cleanup.

    NOTE: Because of the low energies involved, film badges will 
    generally not detect any I-125 exposure unless (1) very large 
    amounts are used; or (2) the I-125 was spilled directly on the 
    badge.

2)  I'm not a physician, so I'll leave that alone, other than to say 
    that there should have been no physical radiation-induced effect 
    from the described accident (IFF there was no radiation burn 
    caused by I-125 sitting on bare skin for awhile).  NOTE: are you 
    referring to a test for thyroid function or for thyroid uptake of 
    radioactive iodine?  There won't be any remaining I-125 from an 
    accident 16 years ago (physical 1/2 life = 60 days; effective 1/2 
    life = ~40 days).

3)  Yes, taking the KI in this instance was an overreaction.  I'd be 
    more concerned that no one realized that this was an overreaction.

I hope this answers your questions.

Wes


> Date sent:      Fri, 18 Oct 96 11:24:11 -0500
> Send reply to:  radsafe@romulus.ehs.uiuc.edu
> From:           Naomi Esmon <esmonn@OMRF.OMRF.uokhsc.edu>
> To:             Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
> Subject:        KI and "Research" accidents

>   After reading the dialogue about KI and nuclear accidents, I have a
> question about the use of KI after I-125 or I-131 biochemistry research
> related accidents.  Many years ago during an experiment, I spilled several
> hundred microcuries of I-125 (assumed 98% of it protein-bound) on my lap.  I
> know the rules say stop immediately and wash everything, but those rules
> were NOT written by someone who FINALLY got the four unstable proteins AND
> cells to be alive on the same day! I therefore continued but had our dept.
> chairman (an MD) run across the street, tell the ER what happened and bring
> me KI as I continued the experiment.  I drank it down (sorry--have NO idea
> what the dose was) within an hour and within 2 hours, managed to change
> clothes and scrub. I don't remember ever checking my uptake.  But my badge
> never registered a thing (except the time it got left in my mailbox in the sun).
> 
> Questions:
> 1. What is the recommended procedure now? If my student or tech has a
> similar occurance, should we get KI as fast as possible? (I could ask our
> RSO, but having the information in my head is a lot faster!) 
> 2. Now that it's been about 16 years, is a thyroid test in order?
> 3. Was this an over reaction [previous chairmain still worries about it]?
> 
> Thanks
> N. Esmon
> esmonn@omrf.uokhsc.edu
> 
> 
*********************************************************************
Wesley M. Dunn, CHP                        512-834-6688
Deputy Director, Licensing                 512-834-6690 (fax)
(Texas) Bureau of Radiation Control        wdunn@brc1.tdh.state.tx.us
*********************************************************************