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Nucl Week on French Acad of Med statement on LNT & "Disinformation"
Friends,
FYI, Nucleonics Week on the French Academy of Medicine statement re the
LNT and "Disinformation":
Regards, Jim Muckerheide
===================
Copyright 2001 The McGraw-Hill Companies, Inc.
Nucleonics Week
December 13, 2001
SECTION: Vol. 42, No. 50; Pg. 1
HEADLINE: FRENCH ACADEMY DENOUNCES NEW LIMITS, RADIATION MISINFORMATION
BYLINE: By Ann MacLachlan, Paris
BODY:
France's Academy of Medicine has renewed its opposition to a
20-milliSievert (2 rem) annual dose limit for professional exposures,
saying such a regulation would ''bring no health benefit while hampering
operation of medical radiology departments by making it more difficult
to develop new techniques.''
The Academy, in a new opinion issued Dec. 4, said France should adopt
without modification the Euratom radiation protection directive, which
sets a professional dose limit of 100 mSv averaged over five years and
doesn't change the current annual exposure limit of 50 mSv.
The French administration is in the final throes of drafting decrees to
enact the 1996 Euratom general directive, as well as a 1997 directive
covering rad protection in medical practices. The French nuclear
industry, too, has railed against the current draft which stipulates a
strict 12-month dose limit of 20 mSv (see related story, page 11). The
Academy also ''denounces'' the use of the linear non-threshold (LNT)
theory to estimate the health effect of doses below a few milliSieverts,
the order of magnitude of the variation in natural background radiation
among French regions. It also condemns the use of the collective dose
concept to estimate health effects, saying ''these procedures have no
scientific validity, even if they appear convenient for administrative
reasons.''
The Academy's statement, entitled ''Medical Irradiation, Radioactive
Waste, and Disinformation,'' was signed by Guy de The, chairman of its
public health commission, and Maurice Tubiana, a renowned cancer
specialist. Other drafters were Andre Aurengo, another well-known
radiotherapist, and Roland Masse, a former director of rad protection
agency OPRI. They are in the forefront of French scientists combating
what they see as the misuse of international radiation protection
recommendations to fan public concern about the health effects of low
doses.
Within the French system, the Academy scientists are often considered to
represent an extreme view and they have clashed on occasion with
radiation protection professionals who appreciate the current system,
including the use of the LNT hypothesis and collective dose, because it
simplifies their lives.
The full Academy adopted the opinion in a unanimous vote Dec. 4.
The statement supplements one issued in October 2000 and goes into more
detail on medical irradiation. In particular, the Academy says that
radiation protection efforts should be increased for medical X-rays to
reduce doses for certain exams, such as scans for young people, and
recommends further measures, such as more training for radiology
personnel. The scientists say it is ''unacceptable'' that while medical
irradiation represents 95% of artificial irradiation received by a
typical Frenchman, ''so few resources'' are devoted to reducing medical
doses compared to the ''high funding'' given to rad protection in power
industry.
X-rays represent an effective dose of about 1 mSv/year in France,
compared to 2-4 mSv from natural sources. The Academy makes several
recommendations about how to optimize medical doses and how to justify
them, two principles required under the Euratom directive 97/43 that
will be enacted into national regulations next year.
'Disinformation'
But the Academy goes further to address what it considers
''disinformation'' that has been circulating recently about the
radiological risks from nuclear waste and the health effects of the
Chernobyl accident.
Concerning radwaste, the Academy says that risk studies should give
priority to isotopes not on the basis of collective dose, but on the
basis of potential individual doses, ''since collective doses calculated
from individual doses below a few microSieverts can have no health
significance.'' Besides supporting more epidemiological studies of
people living in naturally high-radiation areas like India's Kerala
state and of ex-USSR populations exposed to relatively high doses of
nuclear and other contaminants over long periods, the doctors call for a
''significant national effort'' in France, similar to that underway in
the U.S., to study biological mechanisms implicated in cellular response
below 100 mSv.
The Academy scientists assert that it is ''legitimate'' to evaluate
risks from nuclear plant dismantling and waste transport, storage and
disposal programs on the basis of what is known about millions of people
living in high-background areas, since the dose levels are lower in the
case of industrial activities and there's no difference in biological
impact of natural or artificial radiation. They noted that no adverse
health effects have been detected in Kerala or other high-background
areas in studies so far.
The doctors also say the LNT theory of dose-effect relation is disproven
by numerous experimental and epidemiological data. No increase in cancer
has been shown in Hiroshima and Nagasaki survivors at doses below 200
mSv for adults and 100 mSv for children, they asserted, the only
''doubt'' being for in-utero exposure where 10 mSv could be the limit.
The Academy railed in particular against the use of the LNT hypothesis
to evaluate risks from Chernobyl fallout outside the ex-USSR. It said
high doses to thyroids of children in areas near Chernobyl (1-3 Gray
average in the most-exposed regions) have led to about 2,000 cancers,
with about 10 deaths so far. But ''no increase in thyroid affections
that can be attributed to Chernobyl fallout has been shown outside of
the USSR, for example in Poland or other adjacent states,'' it says.
<snip>
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