Transmission of Bucky (Grenz) rays through human scalp hair

The shielding effect of various types of human hair and the influence of a shampoo on the transmission of grenz rays were determined by ionization chamber measurements. The mean transmission proved to be 53.7% with clean hair and 48.1% with hair shampooed one week before. P less than 0.05 (n = 50) (Pratt's test). A relationship was found between weight of hair layer and transmission. In clinical practice, the thickness of the hair should be assessed, and the normal skin dose multiplied by 1.5 for patients with a thin hair layer, by 2 in the case of a medium, and by 3 in the case of a thick hair layer.