Low dose radiation, or ...

["ALDEN N TSCHAECHE" <XAT@inel.gov>]

Sorry, the ICRP doesn't say: "the probability is that small doses do
increase cancer and genetic risks in humans." ICRP-60, pg 67 says:
"Stochastic effects are BELIEVED to occur, albeit with low frequency,
even at the lowest doses and therefore have been taken into account at
all doses"(emphasis added). Beliefs get one in trouble. ICRP 60 also
says, pg 69: "The Commission has estimated the brobability of a fatal
cancer ... These committees have estimated the lifetime cancer risk by
considering ... data ... and projection to lifetime by a multiplic ative
... model, for high dose, high dose rate exposure." Note the words
"estimated", "projection", and "model." The whole ICRP set of
recommendations is based on belief, modeling and projections. THERE ARE
NO DATA DEMONSTRATING LOW DOSES OF RADIATION CAUSE CANCER IN HUMANS.
There are data (Cohen, Evans) demonstrating the linear model doesn't
work for radon in homes and radium in bones. Since the radiation
involved in both of these situationsis alpha, and since many believe
that alphas are more damaging than low LET radiation, is it not
reasonable that, if low level alpha radiation is not harmful, low level
exposures from other, low LET radiation is also not harmful?Al. Tschaeche.

*** Reply to note of 12/04/95 20:57
To: RADSAFE --INELMAIL RADSAFE

Subject: Low dose radiation,  or ...

A little bit of what you fancy does you good.

I am surprised to be continually informed via radsafe that
small amounts of radiation are *probably* good for you.
I know radiation hormesis is a very attractive theory for
health physicists because it means that if we make a mistake
nobody is harmed.   I was there once.   I even got a copy of
the "Health Physics" issue devoted to radiation hormesis in
humans.   I would suggest that those who are saying small
amounts of radiation are *probably* good should read those
papers.   In my opinion the most that can be said is that
small doses may *possibly* be good for you.   And very few
people are going to run even a theoretical risk of cancer
on the strength of evidence like that.

Radiation hormesis is proven for simple systems like plants,
but when international agencies like the ICRP say that the
probability is that small doses do increase cancer & genetic
risks in humans,  then you need strong evidence to the contrary
to ignore that advice.

BTW,  with the inclusion of a dose & dose rate effectiveness
factor (DDREF) of two in the ICRP risk factors (ICRP 60, 1990),
it seems to me that they are no longer applying the LNT model
as such.   This indicates that they are no longer either:

1.  persisting with a discredited risk model;  or
2.  taking a conservative position in the presence of conflicting data.

HP's will have to decide for themselves which of the above
options applies.



Alex Mitchell
hospam@wnmeds.ac.nz