Re: Ukraine's Thyroid Cancer Rate Rises -Reply

[Charles Willis <CAW@nrc.gov>]

Ruth,

The thyroid doses are believed to result largely from exposure to I-131 with some
contribution from I-133.  Thus essentially all the dose was delivered in the first
month.  The World Health Organization (WHO) cites a high risk factor for people
exposed before age 15 years but says that the risk is a function of age with the
younger people being more radiosensitive.  The WHO also says the risk of
radiogenic thyroid cancer is small for people exposed after age 20 and essentially
zero for people over 40.  The increase in childhood thyroid cancer seems to be
detectable in 1989 and clearly is detectable in 1990.  For this analysis, Dr. Buglova
used data for children 0-14.  This does not seem consistent with the A bomb
survivor data but I do not have a good explanation for the difference, unless you
want to attribute the effect to a change in medical practice.  Interesting.

Charlie Willis
caw@nrc.gov
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