Dose effect relationship for epilation and late effects on spinal cord in rats exposed to gamma rays.
The response of rat spinal cords (T7-T12) exposed to single and multifractionated gamma-ray exposures revealed no significant differences between the threshold doses for 2 fractions given with a 24-hr. interval and 2 fractions given with a 15-day interval. The latent period for spinal cord damage was about 190 days when the incidence of paralysis was high; it was less than this in animals with a lower probability of paralysis. There was a marked sparing effect from dose fractionation: the initial part of a Strandqvist type of isoeffect curve had a slope of 0.44 for doses causing paralysis in 50% of the animals, and 0.36 for "threshold" doses. The level of epilation was not useful for predicting spinal cord damage.
D000818:Animals; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays; D006204:Hair Removal; D011832:Radiation Injuries; D051381:Rats; D013116:Spinal Cord / Q000528:radiation effects*; D013119:Spinal Cord Injuries / Q000209:etiology