Re: Iodine Bioassay: NUREG/CR-4884

[stabin@esper.com (Mike Stabin)]

Gus Potter wrote:

>     For iodine, the f1=1, meaning all iodine in the stomach goes 
>     immediately to the systemic whole body, and the only inhalation class 
>     is class D meaning that there is no long term lung retention.  Since 
>     this is the case, the inhalation and ingestion models act the same 
>     (after a few days after intake) except for the 37% exhalation that is 
>     assumed in the lung model.  Therefore, you should just be able to 
>     multiply the ingestion IRFs by 0.37 to get those from inhalation.  To 
>     account for the radioactive isotopes, you can just multiply by the 
>     decay factor.

Not quite.  There is some significant decay of I-131 in the lung on its way
to the systemic circulation.  Note the difference in thyroid Us's in ICRP 30
for inhalation and ingestion.

I don't have the NUREG here at home, but I will look at it when I drop in at
work.  Between that and ICRP 54, I find it hard to believe there are no
available IRFs for inhalation of iodines.  But if not, I can calculate some,
and will post them.

Mike Stabin
Radiation Internal Dose
  Information Center
Oak Ridge, TN
423-576-3449  ph
423-576-8673  fax
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