Re: Potassium Iodide -Reply -Reply

["J. J. Rozental" <josrozen@netmedia.net.il>]

As mentioned by Charlie Willis: "Then there are the practical difficulties
of actually administering KI in a timely manner, preferably shortly before
the inhalation of the radioactive iodine." 

a) He is correct, the administration of stable  iodine to a population is
not a simple operation. The decision  has to be made a priori whether this
planning is warrented, or is more  appropriate to rely on other protective
actions, such as  sheltering or evacuation;
b) The level of planning and preparedness itself will have  to be justified,
since it  can range from simply making tablets available in pharmacies to
rapid distribution to the public, to predistribution to households;
c)Which level is appropriate will depend on the total cost of the
preparedness plans, the expected benefits in terms of risk reduction, with
account taken of the probability of an accident that would warrant such a
measure, and social, psychological and political factors;
d) ICRP 60 estimates the mean probability of thyroid cancer, both fatal and
non-fatal to be 7.5(E-3) per Gray absorbed dose to the tyroid, fatality rate
of these cancer is about 10%, The probability of thyroid cancer varies
markedly with age; infants are more at risk than adults;
e) The probability of side effects from the intake of stable iodine  differ
widely, mainly because the differences in the dietary intakes of iodine and
the prevalence of thyroid diseases. 
f) The risk of death following iodine prophylaxis is of the order of 3(E-9).
The experience gained in Poland following the Chernobyl accident showed an
incidence in adults of 4(E-7) of severe health effects and an incidence of
6(E-4) for mild to moderate effects;
g) No adverse effects were reported in the 1o  million children who took
potassium
iodine. 
h) The value of 100 mGy to the thyroid for Generic Intervention Level for
Iodine prophylaxis selected by the IAEA, it has been selected towards the
higher range of optimized levels, to be consistent with the recommendation
of the ICRP 63.

J. J. Rozental <josrozen@netmedia.net.il>
Israel 


At 10:23 AM 7/23/98 -0500, you wrote:
>RadSafers,
>
>Re:  prophylactic KI administration during nuclear reactor emergencies.
>
>To help frame the debate/comments, I suggest the proposed NRC
>recommendations be applied to real life scenario, namely the TMI
>accident.  (I'm assuming that Chernobyl-magnitude releases would be
>highly improbable in countries using light-water reactors)  Under the
>proposed recommendations:
>
>1) would KI had been issued (or would the populace be advised to take
>KI)?
>2) to how many people?
>3) at what cost?
>4) preventing how much thyroid cancer (or decreasing thyroid cancer risk
>by what)?
>5) how many adverse reactions can be expected (either K or I
>sensitivities)?
>6) how many deaths could occur from these adverse reactions?
>
>These estimates would be useful in judging the efficacy of the proposed
>recommendations.  Having grown up in the shadow of TMI, I'm also
>interested to learn if  KI really would have helped the situation...
>
>-Scott Sorensen
>ssorensen@doeal.gov
>
>