Re: Question on low-dose rad effects

["Otto G. Raabe" <ograabe@ucdavis.edu>]

October 23, 1999
Davis, CA

The minimum cumulative dose require to produce bone cancer in a mouse, a
beagle, or a person is about one gray in each species (about 0.5 to 1.1
Gy). The number of cells at risk in each species is dramatically more in
people than in a mouse, but about the same dose (energy per gram of tissue)
is needed to induce bone cancer during the nominal lifetime (Raabe et al.,
SCIENCE 208, 61-64, 1980). In addition, when you consider that the lifetime
of the mouse is much shorter than the other species (limiting the cancer
induction time), the radiation induced cancer is seen to be much more
efficient in mice who have fewer cells at risk than in humans or beagles
who have many more cells at risk. These findings are inconsistent with the
hypothesis that radiation carcinogenesis is simply a random stochastic
process.

Otto

		*****************************************************
		Prof. Otto G. Raabe, Ph.D., CHP
              Institute of Toxicology & Environmental Health (ITEH)
		   (Street address: Building 3792, Old Davis Road)
		University of California, Davis, CA 95616
		Phone: 530-752-7754  FAX: 530-758-6140
		E-mail ograabe@ucdavis.edu
              *****************************************************
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html