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Re: Thyroid cancer and I-131
Mike Quastel wrote:
>
> Bjorn Cedervall's comment regarding different adult and childhood thyroid
> sensitivities to radiation is relevant since, as he mentions, the L-E Holm
> studies were conducted with adults.
Actually it's not relevant to the issue, which was cancer/leukemia
following I-131 hyperthyroid therapy dose to whole body/bone marrow, NOT
thyroid cancer from diagnostic I-131.
> There seems to be little doubt that the significant increase of childhood
> cancer (though not adult cancer) of the thyroid in Belarus and Ukraine was
> caused by incorporated Chernobyl radioiodines (I-131 together with the more
> short lived I-132, I-133 and I-135 (with half lives of 2.3 hrs, 21 hrs &
> 6.7 hrs respectively). Although dosimetry has been very difficult for these
> populations, it seems likely that the thyroids of young children are more
> radiosensitive than those of adults
Dosimetry is more than 'difficult', but your very important point about
the short-lived iodines seems, if anything, to not have yet been fully
considered for a power reactor that experienced the fission-product
generation of a nuclear power excursion AFTER it had been lifted 12-15
meters by a steam explosion at the base, destroying the building and
causing the immediate and 4-day fire to rapidly distribute the volatile,
and particle, fission products.
It is also important to acknowledge that the rad-effects are shown to
indeed be very much greater to infants from -6 months (fetus) to +5
years. And are still only about 4 deaths, and only then due to emergency
response and medical treatment failures. But the uncertainty of how high
the dose actually was to these infant thyroids, and related biological
influences, is very great.
> In Belarus and the Ukraine the increased incidence of childhood thyroid
> cancer has been found yearly since 1990 ( Kazakov et al,1992; Baverstock et
> al, 1992; Likhtarov et al,1995) Most investigators have gone on record as
> supporting the likelihood that the increase of cancer of thyroid is real
> (Abelin, 1994). Williams (1994) rather than a consequence of improved
> surveillance.
I don't know anyone who claims that HIGH doses do not contribute to an
increase in certain cancers (though often even then not to an increase
in total-cancer!?)
> Other evidence for (non-malignant) radiation effects of environmental
> radioiodine in chidren include a recent report of juvenile hypothyroidism
> in 2 exposed populations, one being the Hanford downwinders and the second
> being the population living in regions near Chernobyl (Goldsmith et al
> 1999).
This is hardly credible, even if "easily treatable" _hypothyroidism_
is a meaningful "effect" as a result of "massive releases" from Hanford
("an estimate of 550,000 Ci in 1945 and 166,000 Ci of 131I during 1946
through 1952"), and "massive emissions from Chernobyl", are relevant to
concerns about low-level radiation exposures. According to the paper:
"The Hanford Environmental Dose Reconstruction (HEDR) project found
strong evidence that thyroid glands of large numbers of individuals,
particularly children, were likely to have been exposed to doses in the
range of several hundred rad." The abstract is at:
http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=10090710&form=6&db=m&Dopt=b
The Hanford downwinder survey was/is organized by anti-nuclear activists
and self-selected responders, with only 801 "usable" forms out of
1500-2000 (no record of how many?!) distributed by "concerned
downwinders", in a politically-charged campaign of posturing about great
"health concerns" and anti-DOE rhetoric (from my experience as a
"Hanford downwinder", 1947-49, as a mere CHILD :-). Hardly a sound
scientific conclusion (which the paper does NOT offer it to be, but
which does not adequately qualify the limitations either. (Could only
have been pub'd in EHP?! :-(
Also, for Chernobyl there are about 2 cases/1000 children examined <10
years at the time of the accident, with "dose" only "correlated with
body burdens of 137Cs", with no substantial consideration of how the
Cs-137 would have followed the radioiodines or other short-lived gaseous
radioisotopes.
The full paper is at:
http://ehpnet1.niehs.nih.gov/members/1999/107p303-308goldsmith/goldsmith-full.html
[You may need to "subscribe" - it's free.]
Again, this trivial "effect' is hardly support for the concepts of
radioactivity control that are applied in accordance with the LNT
"models" - they support NO low-level radiation-related concern. Indeed,
it would be more justifiable to conclude that Chernobyl, and the Hanford
releases, prove the absense of significant effect from large releases of
radioactivity, to be applied to design and clean-up standards!
Perhaps others could check the abstracts of the other refs below to see
how well they support the radioactivity/dose-response.
> Abelin, T. (1994) Thyroid cancer in Belarus post-Chernobyl: Improved
> detection or increased incidence. Soz Präventivmed 39, 189-197.
http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=7941769&form=6&db=m&Dopt=b
> Baverstock,K.et al (1992) Thyroid cancer after Chernobyl. Nature 359, 21-22.
A letter, no text.
> Kazakov, V. et al (1992) Thyroid cancer after Chernobyl. Nature 359, 21.
A letter.
> Likhtarev, I.A. et al (1995) Thyroid cancer in the Ukraine. Nature 375, 365.
A letter.
> Goldsmith JR et al (1999) Juvenile hypothyroidism among 2 populations
> exposed to radioiodine. Environ Health Perspect 107:303-308 (1999).
>
> Williams, E.D. (1994) Chernobyl, eight years on. Nature 371, 556.
Of 7 papers by "E. Williams" in Nature, in all years, this is NOT in medline.
> Mike Quastel
> Nuclear Medicine
> Soroka Medical Center and
> Faculty of Health Sciences,
> Ben Gurion University of the Negev
> Beer Sheva, Israel
> maay100@bgumail.bgu.ac.il
Regards, Jim Muckerheide
muckerheide@mediaone.net
Radiation, Science, and Health
==============================
> ---------------------------------------------------------------------------
> >Just a comment: The L-E. Holm studies on I-131 and treatment for
> >hyperthyroidism (from around 15-20 yrs ago) concerned only adults. I think
> >that it is always important to make this distinction. I have seen a "green"
> >discussion about childhood thyroid cancer and then refs. to L-E. Holm's work
> >(to downgrade it) without a proper note about the child/adult difference.
> >Did Dr. R. Yalow publish any research studies on the risks of I-131 BTW (did
> >I miss any references?)?
> >
> >bjorn_cedervall@hotmail.com
> >Any opinions expressed above are those of mine and may not necessarily
> >coincide with those of others.
> >
> >
> >
> >
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