Quantification of radiation-induced epilation in the pig: a biological indicator of radiation dose to the skin

Epilation in the pig has been quantified following single exposures of X-rays in the range 1.0-25.0Gy. Hair loss was dose-dependent for exposures between 1.0 and 15.0 Gy and this response was linearly related to dose. No further increase in hair loss was observed for doses ≥ 15.0 Gy as 20-30% of the hairs remained. It was assumed that these hairs were not actively growing at the time of irradiation and did, therefore, not express damage. The ED50 for the loss of ≥ 30% of hairs was 3.8 Gy whilst that for the loss of ≥ 50% of hairs was 6.8 Gy and for the loss of ≥ 67% of hairs was 12.5 Gy. There was ± 7% hair loss per Gy exposure for doses between 0.0 and 15.0 Gy. Quantification of hair loss provided a more sensitive assay than the use of visual scoring systems. Hair loss was detectable within 4 weeks of irradiation. The system is simple, non-invasive and appears to have considerable potential for use as a biological dosemeter. (Author)