The dose-latent period relationship in the irradiated cervical spinal cord of the rat.

The cervical spinal cords of young adult female rats were irradiated with various single and fractionated doses of 250 kV x rays. No relationship was evident between the dose and the latent period for myelopathy after irradiation of the rats' cervical cords, i.e., there was considerable variation in the mean latent periods between different groups of animals given a fixed single dose (4,000 rads). It was concluded that the latent period for myelopathy following irradiation of the cervical cord of the rat is not a reliable experimental end point for radiobiological investigations.