[ RadSafe ] definition of Rad

[Colette Tremblay]

Hi:

The Wikipedia entry states:

"The rad was first defined in 1918 as the unit of X-ray dose required to kill a mouse.[1]"

And the reference given is:

[1] Russ S, Arch Rad and Electrotech 23, 226, 1918 according to Jerrard and McNeil (1992). Dictionary of Scientific Units. Chapman and Hall.

Our library has the 1986 edition of Jerrard and McNeil. I'm going to check it.

Colette
---
Colette Tremblay
Spécialiste en radioprotection
Service de sécurité et prévention
Université Laval

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Colette.Tremblay at ssp.ulaval.ca
www.ssp.ulaval.ca/sgc/radioprotection
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Message relatif à la confidentialité:
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-----Message d'origine-----
De : radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] De la part de Rainer.Facius at dlr.de
Envoyé : 4 octobre 2007 05:44
À : eic at shaw.ca; radsafe at radlab.nl
Objet : AW: [ RadSafe ] definition of Rad

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

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
GERMANY
Voice: +49 2203 601 3147 or 3150
FAX:   +49 2203 61970

________________________________

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



Friends,

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?

Kai

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