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Ricky
The long-term iodine uptake by the thyriod is not
important for emergency response. The important parameter is the fraction of
iodine that enters the blood that goes to the thyroid before it is excreted. The
models I programmed a long time ago had competing routes to take this into
account. The ICRP model(s) have never done this!
Check the following for more
information.
RADIOIODINE DOSIMETRY
J.R. Johnson
Special
Symposium Proceedings Issue of the Journal of Radioanalytical Chemistry
65 (1981) 223-238, AECL-7381.
FETAL THYROID DOSE FROM INTAKES OF RADIOIODINE BY
THE MOTHER
J.R. Johnson
AECL-7694, Health Physics 43 No. 4 (1982)
573-582.
A REVIEW OF AGE
DEPENDANT RADIOIODINE DOSIMETRY
J.R.
Johnson
Published in "Age-related Factors in
Radionuclide Metabolism and Dosimetry", G.B. Gerber, H. Métivier, and H. Smith,
Eds., 249-260 (1987). Proceedings of a workshop held in Angers,
France, November 26-28, 1986, sponsored by the Commission of the European
Communities.
RECYCLING AND
METABOLIC MODELS FOR INTERNAL DOSIMETRY: WITH SPECIAL REFERENCE TO
IODINE
J. R. Johnson
Radiation Protection Dosimetry, Vol. 27, No. 1 (1989) 57-58.
John
----- Original Message -----
Sent: Monday, November 19, 2001 8:13
AM
Subject: RE: [Fwd: [OEM] [OEM!] US Bill:
Mandatory KI Stockpiling]
However, regardless of the stable iodine loading in
the population, I believe that the thyroid dose from a radioiodine intake
would be the same.
para 103 ICRP 56 (1989), "In the dosimetric model used for adults
(ICRP, 1979) the normal adult gland is taken to contain 10,000 ug of stable
iodine with a biological half-time of 80 days. After its entry into the blood,
the fractional uptake of of iodine by the gland is taken to be 0.3. However,
this varies considerably among individuals and in different countries as a
result of different levels of stable iodine in the diet (Stather and
Greenhalgh,1983). In countries with a very low intake of stable iodine the
accumulation of radioiodine by the gland is increased. The low-level of
iodine in the diet will, however, have resulted in a compensatory increase in
the mass of the thyroid with the result that the concentration of radioiodine
in the thyroid would be similar to that calculated using the standard model
(Heinrichs et. al. 1983)".
The statement attributed to
Henrichs et. al. seems to indicate that thyroid dose is relatively insensitive
to dietary iodine deficiencies or sufficiencies because of a compensatory mass
increase in the thyroid.
I have been looking for
some time for evidence to support or contradict the view esposed above...
Ricky Khaloo
Site Health Physicist
Atomic Energy of Canada Ltd.,
2251 Speakman Drive, Mississauga, Ontario
khaloor@aecl.ca
905.823.9060 ext. 4532
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