AW: [ RadSafe ] definition of Rad

Rainer.Facius at Rainer.Facius at
Thu Oct 4 04:43:47 CDT 2007

you may need up to thousand rads (up to 10 Gy)  of acute sparsely ionizing radiation to kill an adult healthy mouse.

Morton  J I, Siegel B V, Radiation Sensitivity of New Zealand Black Mice and the Development of Autoimmune Disease and Neoplasia. Proc Natl Acad Sci U S A. 68#1(1971)124-126.

"Young New Zealand Black (NZB) mice manifested extremely high resistance to the lethal effects of acute exposures to ionizing radiation, with a dose necessary to kill 50% of the animals within 30 days, LD50(30), of 964 roentgens (R) at 30 days of age and of 856 R for 90-day-old mice. In contrast, Coombs' positive 9-month-old NZB mice (with low primary immune response) were highly susceptible (LD50(30) = 543 R), possibly because of anemia-stimulated erythropoiesis leading to a depletion of stem cells."
Dr. Rainer Facius
German Aerospace Center
Institute of Aerospace Medicine
Linder Hoehe
51147 Koeln
Voice: +49 2203 601 3147 or 3150
FAX:   +49 2203 61970


Von: radsafe-bounces at im Auftrag von Kai Kaletsch
Gesendet: Di 02.10.2007 18:10
An: radsafe at
Betreff: [ RadSafe ] definition of Rad


According to the Wikipedia entry for 'Rad', it was defined from 1918 to 1953 as the unit of X-ray dose required to kill a mouse. 1) I never heard this definition before and 2) This seems like a very low dose for killing anything.

This is somewhat before my time and I normally use SI units. Is the Wikipedia statement correct?


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