Re: Query to Roger Clarke

[muckerheide@highway1.com (James Muckerheide)]

Otto G. Raabe wrote:
> 
> May 8, 1997
> 
> Dear Wade:
> 
> Please tell me where in ICRP-60 I can find a statement that says: "We cannot
> say whether the model (LNT) overestimates the risks of exposure to low levels of
> radiation or not, and so, while the real risks may be zero we are going
> to be on the safe side and use the LNT."

Dear Dr. Raabe,

The National Council of Radiation Protection and Measurements (NCRP)
Report 121 (11/30/95) on Collective Dose summarizes the current status
of LNT theory:

"...essentially no human data, can be said to prove or even to provide
direct support for the concept of collective dose with its implicit
uncertainties of nonthreshold, linearity and dose-rate independence with
respect to risk.  The best that can be said is that most studies do not
provide quantitative data that, with statistical significance,
contradict the concept of collective dose...

"Ultimately, confidence in the linear no threshold dose-response
relationship at low doses is based on our understanding of the basic
mechanisms involved.  ...[Cancer] could result from the passage of a
single charged particle, causing damage to DNA that could be expressed
as a mutation or small deletion.  It is a result of this type of
reasoning that a linear nonthreshold dose-response relationship cannot
be excluded.  It is this presumption, based on biophysical concepts,
which provides a basis for the use of collective dose in radiation
protection activities".  

> The possibility that "a single event at the cellular level can give rise to
> cancer" is irrelevant. Surely the probability is not zero. The relevant
> question is rather whether a single event at the cellular level has
> one-millionth the probability of causing cancer as does one million such
> cellular events.

This relevant question of non-linearity goes further: The DNA damage
rate is 10s of millions of times greater than DNA damage from background
radiation. The repair processes at both the DNA and cellular level
generally control this rate of damage (until they are reduced by aging,
with cancers in younger people caused by reduced immune repair
competence). 

Since low-dose/dose-rate radiation stimulates the primary DNA and
cellular repair functions and processes, eg, expression of the p53 gene,
and apoptosis, among other cellular level signalling and physiological
processes (eg, positive effects on membrane fluidity, etc), the
incremental "single event" effect is improved repair and cell function
affecting this high background of DNA and cellular damage. Therefore, it
contributes a "negative probability of producing cancer". 

Drs. Sohei Kondo, and Gunnar Walinder, and others in biology have shown
that cancer is a multi-stage process, and that an improvement in DNA and
cell repair effects each stage. The incremental "single event" is
therefore beneficial. As Ken Bogen at LLNL has demonstrated, using only
a 2-stage model, and applying one repair mechanism (apoptosis), the
effect of a small increment of radiation reflects the biological
plausibility of the resulting "beneficial effects" in Bernie Cohen's
data for reducing lung cancer by the radiation-induced stimulation of
these biological repair mechanisms. 

Of course, all of this has been shown with small organisms for decades.
In another "accident of science", like penicillin, the difference in
growth rate of colonies of paramecium was found to be the result of
being cultured on slides with different thorium sources! :-) Subsequent
experiments confirmed the consistency of this result. (And of course,
years - decades - of experiments by Panel and associates in France, and
dozens of researchers conducting hundreds of independent experiments
around the world, confirm  these results. Further, Planel's group, Don
Luckey, and others, have suppressed background radiation in a variety of
ways - from mines to balloons, and using potassium without K-40 - and
shown consistent decrements in the health, life-cycle, and function of
such organisms.) 

As early as 1896, Shrader at U. Mo. contradicted JJ Thompson's claim
that Roentgen's x-ray would not be bactericidal by injecting guinea pigs
with diptheria bacillus, and seeing those exposed to x-rays live while
those unexposed died within 24 hours from diptheria. :-)  But we don't
have resources to study the beneficial effects on immune response
because we need funds to "study" us "Hanford downwinders" (in my case
'46-'49 :-) and to clean dust off of dirt in the desert :-)  ("I do not
hesitate to say that this is the greatest scientific scandal of the
century." Walinder, radiobiologist, associate of Rolf Sievert, UNSCEAR
and ICRP)

> Best regards,
> 
> Otto

Thanks very much. (And for your great effort to carry the message on the
radium populations to the HP community, mostly trained explicitly
without any knowledge of the biological studies, only the linear mantra
as approved by the Fed agencies with rad protection interests - there's
no 'health' in HP :-)

Regards, Jim Muckerheide
jmuckerheide@delphi.com

> At 11:24 PM 5/7/97 -0500, you wrote:
> >Group:
> >I think we're all aware that UNSCEAR, BEIR, ICRP, and NCRP (UBIN) have
> >consistently inserted a disclaimer in their various pronouncements.
> >
> >It always seems to go something like this; "We cannot say whether the
> >model (LNT) overestimates the risks of exposure to low levels of
> >radiation or not, and so, while the real risks may be zero we are going
> >to be on the safe side and use the LNT."
> >
> >This puts those who wish to challenge whether risks are associated with
> >small doses in the position of having to prove that they are not.
> >Unfortunately, proving a negative is difficult, if not impossible.
> >
> >I think it would be better to take Roger Clarke (ICRP Chair), and
> >others, at their word when they say, "a single event at the cellular
> >level can give rise to cancer", and ask them to prove that this is true.
> >
> >I wonder what evidence they would offer ?
> >
> >Best wishes.
> >
> >--
> >Wade
> >
> >mailto:hwade@triax.com
> >
> >H.Wade Patterson
> >1116 Linda Lane
> >Lakeview OR 97630
> >ph 541 947-4974
> >
> >
> >
>                 *****************************************************
>                 Prof. Otto G. Raabe, Ph.D., CHP
>                 Institute of Toxicology & Environmental Health (ITEH)
>                 University of California, Davis, CA 95616
>                 Phone: 916-752-7754     FAX: 916-758-6140
>                 E-Mail: ograabe@ucdavis.edu
>                 ******************************************************