[ RadSafe ] dose RATE of ANY Medicine is the decisive variable

[goldinem at songs.sce.com]

Ted wrote the following note that really contains a very important
question.  I've asked this before on Radsafe and never got an answer.

"I understand that much (I think), but is there a real biological, and
logical, basis for saying that the processes involved in radiation damage
(and healing, or progression to cancer)  are of a fundamentally different
kind than damage from metabolism or other stimuli?  For if they are, then
the whole Pollycove/Feinendegen argument fails.  I think a lot hangs on the
validity, or invalidity of the argument (that seems to trump all others)
that ³Yeah, but radiation is different.²
I¹d like to get really clear on that."
Ted Rockwell

Here's the conundrum:  If radiation (at least low-LET) causes the same type
of damage as metabolic processes, then the rate of chronic radiation is
lost in the ocean of free radical formation in the cell and is swamped by
normal DNA damage/repair processes.  Hence, low dose radiation cannot have
any significant effect, positive or negative.  However, if the damage is
different (multiply damaged sites, as shown by Dr. John Ward), then one
needs to postulate what is going on that would cause the cellular reactions
to stimulate the immune system, cause apoptosis, or whatever other positive
reaction is believed to occur by hormesis proponents.  I've followed (and
conducted some) molecular radiation biology studies for a long time and
just don't see the magnitude or depth of understanding in those
tissue/organism responses as has been done in molecular/cellular work over
the past 50 years.  (And incidentally, I've never seen any evidence of a
conspiracy, no matter how much fun it would have been.)

Eric M. Goldin, CHP
<goldinem at songs.sce.com>