AW: AW: [ RadSafe ] dose RATE is the decisive variable

[John Jacobus]

Rainer,
Maybe I am just not that impressed with this "changing
of spectacle."  Sorry.  I certainly do not about the
proof or overthrow of the LNT hypothesis.

Have a good weekend.

--- Rainer.Facius at dlr.de wrote:

> Dear John:
> 
> Neither I nor Gregoire&Cleland claimed that a
> breakthrough has already been achieved. 
> 
> All I did was to state that usually an exchange of
> the spectacles is one of the prerequisites that this
> can happen. Only such a change has been invoked by
> the authors and some of the consequences have been
> explored. The future will show whether a
> breakthrough will ensue or not. Sterile invocations
> of an LNT postulate with neither a theoretical nor
> an empirical basis certainly will lead to nowhere -
> as the last half century testifies.
> 
> Kind regards, Rainer
> 
> 
> ________________________________
> 
> Von: radsafe-bounces at radlab.nl im Auftrag von John
> Jacobus
> Gesendet: Fr 01.09.2006 20:52
> An: radsafe
> Betreff: Re: AW: [ RadSafe ] dose RATE is the
> decisive variable
> 
> 
> 
> Rainer,
> So, what is the lasting breakthrough that they are
> presenting?  Why is the DDREF not a variable that
> quantifies the effect?  Or rather how is their
> "variable" different from the DDREF?
> 
> --- Rainer.Facius at dlr.de wrote:
> 
> > Dear John:
> >
> > You are absolutely right, they offer no new
> > information as far as data are concerned. What is
> > new are the exchanged spectacles through which the
> > authors examine the old data. Many if not most of
> > the real and lasting breakthroughs in science were
> > inaugurated by simply changing the goggles. In the
> > present context this means that the authors do NOT
> > account for dose rate by a DDREF parameter but
> treat
> > it as the variable quantifying the real cause.
> >
> > I myself did not include any data but those which
> > were analyzed in the original paper which is worth
> > being scrutinized properly.
> >
> > Kind regards, Rainer
> >
> >
> > ________________________________
> >
> > Von: John Jacobus [mailto:crispy_bird at yahoo.com]
> > Gesendet: Fr 01.09.2006 19:48
> > An: Facius, Rainer; radsafe at radlab.nl
> > Betreff: Re: [ RadSafe ] dose RATE is the decisive
> > variable
> >
> >
> >
> > Rainer,
> > Interesting paper and chart.  However, I do not
> > think
> > this is really new information, which is noted in
> > the
> > abstract of the paper.  It was demonstrated at the
> > turn of the 20th century that fractionated doses
> > delivered to therapy patients increased the chance
> > of
> > survival.  Factionation allows for replication and
> > repopulation of normal tissue into the tumor site.
> > Tables were developed to establish proper
> > factionation, and the earliest I have seen is from
> > 1914.  Even the BEIR committee recognizes there
> > exists
> > a dose and dose-rate effectiveness factor (DDREF).
> >
> > It would seem to me the way to demonstate a dose
> > rate
> > effect.  However, you have included the A-bomb and
> > external beam (therapy?) data, to determine your
> > "threshold."  There is not dose-rate effect with
> the
> > A-bomb data.  Without this data set, I doubt that
> > you
> > can show a threshold exists.
> >
> > Looking at the data, I appears that the data for
> > external beam represents the exposure rates where
> > the
> > "capacities" of the system are becoming
> > "overstrained."  Essentially, the patient is
> > receiving
> > a great deal of radiation over several weeks, but
> > not
> > over their lifetime.
> >
> > --- Rainer.Facius at dlr.de wrote:
> >
> > > The recent paper below elaborates a seemingly
> > > trivial principle, i.e., the response of (not
> only
> > > nonlinear) systems capable of intrinsic
> > > counteractive measures to compensate external
> > > stimuli is not primarily determined by the
> > stimulus'
> > > amplitude but rather by the ratio between the
> > > stimulus' temporal gradient and the
> characteristic
> > > 'response' time of the system's feed-back
> control
> > > systems - as long as its capacities are not
> > > overstrained. Thus the rate is not a parameter -
> > as
> > > conventionally it is conceived of - but a
> primary
> > > independent variable.
> > >
> > > Applying this 'law' to that subset of 13
> > > epidemiological studies which have been compiled
> > by
> > > UNSCEAR 2000 and which provide the necessary
> data
> > to
> > > pursue this approach (no cherry picking!), the
> > > authors arrive at a rather provocative result. I
> > > have prepared a graph from their table similar
> to
> > > their own but somewhat enhanced to facilitate
> the
> > > contemplation and mental digestion of these data
> > > which at face value would suggest that a
> threshold
> > > (or even the region for beneficial effects in
> > terms
> > > of cancer mortality) extends to much higher
> > chronic
> > > exposures (rates) than so far publicly discussed
> > > (e.g. the 5 mrem annually invoked the other day
> by
> > > Bernard Cohen). I attach that graph as PDF,
> hoping
> > > it will pass the moderator.
> > >
> > > Enjoy, Rainer
> > >
> > > Gregoire O, Cleland M.
> > > Novel approach to analyzing the carcinogenic
> > effect
> > > of ionizing radiations
> > >
> >
>
<http://www.ingentaconnect.com/content/tandf/trab/2006/00000082/00000001/art00002>
> > >
> > > International Journal of Radiation Biology
> > > 82#1(2006)13-19
> > >
> > > Abstract:
> > > Purpose: Cancer incidence of ionizing radiations
> > > exposure is considered to be proportional to the
> > > absorbed dose. However, there are disagreements
> > > between substantial amounts of epidemiological
> > > studies. In this study, we question the basic
> > > relationship of the risk estimate with total
> > > accumulated dose, and reanalyse available data
> on
> > > the basis of a daily dose concept.
> > >
> > > Materials and methods: The data analysed were
> > > relative mortality risk from all cancers vs.
> > > total-body dose on a daily basis. References
> have
> > > been selected on the basis of objective
> criteria.
> > >
> > > Results: We found that this relationship removes
> > > major discrepancies. It revises estimates of
> > > low-level exposures, with consequences regarding
> > > nuclear power plants safety, wastes management,
> > > medical applications or homeland security.
> > >
> > > Conclusions: The idea that the dose rate may
> have
> > a
> > > significant impact on health effects of ionizing
> > > radiations is not new, but has always been
> > > considered as a parameter in models based on
> > > integrated dose. The novel approach in this
> paper
> > is
> > > to consider the primary relevant parameter as an
> > > average of dose rate over a time period of one
> > day.
> > > This is an argument to revise the whole
> philosophy
> 
=== message truncated ===


+++++++++++++++++++
May we never confuse honest dissent with disloyal subversion. 
Dwight D. Eisenhower  

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com

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