The Effect of X Rays of Different Qualities on the Alkaline Phosphatase of Living Mouse Bone

Abstract

Quantitative measurements have been made of the reduction in the phosphatase activity of mouse bone following doses of X rays generated at 100 kVp, 185 kVp and 1000 kVp. An initial recovery effect has been found for doses not exceeding 1500 r, succeeded by a later and apparently permanent reduction in phosphatase production. Little recovery is observed for doses greater than 1500 r. The depression in phosphatase activity is shown to be the same for 100 kVp and 185 kVp X rays and to be approximately 1·35 times greater than that for 1000 kVp X rays. Detailed calculations have been made of the energy absorption in small thicknesses of soft tissue adjacent to and embedded in bone. These results applied to reasonable models of the phosphatase-bearing tissues are shown to follow qualitatively and quantitatively the measured ratios of the loss of phosphatase activity.