AW: [ RadSafe ] dose RATE is the decisive variable
crispy_bird at yahoo.com
Fri Sep 1 13:52:18 CDT 2006
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
> Interesting paper and chart. However, I do not
> this is really new information, which is noted in
> abstract of the paper. It was demonstrated at the
> turn of the 20th century that fractionated doses
> delivered to therapy patients increased the chance
> 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
> a dose and dose-rate effectiveness factor (DDREF).
> It would seem to me the way to demonstate a dose
> 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
> can show a threshold exists.
> Looking at the data, I appears that the data for
> external beam represents the exposure rates where
> "capacities" of the system are becoming
> "overstrained." Essentially, the patient is
> a great deal of radiation over several weeks, but
> 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
> > 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 -
> > conventionally it is conceived of - but a primary
> > independent variable.
> > Applying this 'law' to that subset of 13
> > epidemiological studies which have been compiled
> > UNSCEAR 2000 and which provide the necessary data
> > 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
> > of cancer mortality) extends to much higher
> > 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
> > of ionizing radiations
> > 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
> > 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
> > to consider the primary relevant parameter as an
> > average of dose rate over a time period of one
> > This is an argument to revise the whole philosophy
> > in radioprotection, and place regulatory limits on
> > specific locations instead of annual limits
> > to individual persons.
May we never confuse honest dissent with disloyal subversion.
Dwight D. Eisenhower
John Jacobus, MS
Certified Health Physicist
e-mail: crispy_bird at yahoo.com
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
More information about the RadSafe