The Effect of Divided Doses of 15 MeV Electrons on the Skin Response of Mice

Abstract
The skin reaction of the irradiated mouse leg has been used to determine the ‘sparing’ effect of dose-fractionation on a normal mammalian tissue. The total dose in two fractions (D2) required to produce the same effect as a single fraction (D1) was determined for intervals of 2 to 42 hours. A rapid increase of D2 – D1 up to 4–5 hours was observed. Irradiations were carried out in oxygen, air and nitrogen and the values obtained for (D2 – D1) at 24 hours in air and oxygen were in the range 300–880 rads (15 mev electrons). These agree well with the findings previously reported on pig and human skin. Hypoxia has been demonstrated to affect the response of the mouse skin irradiated when the animal was breathing air or oxygen at normal atmospheric pressure.