Re: I-131 Thyroid Uptake

[Richard Smart <R.Smart@unsw.edu.au>]

Dear Radsafers.

The MIRD Committee used a fractional thyroid uptake of between 0.05-0.25
for the range in the adult euthyroid person.  This was used by the ICRP in
preparing ICRP Publication 53 which gives dosimetry for 0%, 5%, 15%, 25%,
35%, 45% and 55% thyroid uptake - the latter cases being appropriate for
patients with hyperthyroidism.


It is generally agreed that the fractional uptake will be the same whether
injected or ingested, as iodine is normally totally absorbed.

Regards

Richard

At 12:09 P 27.1.99 -0600, you wrote:
>Does anyone have references to suggest for answers to the following
questions:
>
>What is the typical percent of a iodine intake (we happen to be concerned
with I-131) that will be taken into the thyroid gland?  My 1972 copy of
Shapiro, "Radiation Protection" says 30%, but there is some indication that
it may be as low as 3% (at least for some individuals) according to other
sources.
>
>So, is the answer a range, say about 3 to 30%?  Does the pathway make a
difference, e.g. nuclear medicine injection vs. reactor release and
subsequent accidental inhalation?
>
>Thanks,
>Mike McCarty
>Health Physicist/Emergency Planner
>mccartmj@state.mi.us
>
>Michigan Department of Environmental Quality
>Drinking Water and Radiological Protection Division
>Radiological Protection Section
>Nuclear Facilities Unit
>   phone:  517-335-9414
>     fax:  517-335-8706
>
>mailing address:
>     Michigan Department of Environmental Quality
>     Drinking Water and Radiological Protection Division
>     3423 North Martin Luther King Jr. Blvd
>     P.O. Box 30630
>     Lansing, MI 48909-8130
>
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>
Richard Smart PhD
Department of Nuclear Medicine
St. George Hospital
Kogarah, NSW 2217
Australia
Tel:61 2 9350 3112
Fax:61 2 9350 3991
Email:R.Smart@unsw.edu.au
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