Effect of Internally Deposited Radioisotopes upon Blood Vessels of Cortical Bones. ∗

Abstract

Summary

It has been observed that after an extensive latent period following acquisition of plutonium. radiothorium and radium in cortical bone, plugging of the haversian canals occurs which in turn results in bone necrosis. Investigation of this phenomenon with a vascular injection technic and a bone-seeking alpha emitter (plutonium) which deposits on surfaces of haversian canals and allows the remainder of the osteones and adjacent interstitial lamellae to be free of activity, show that death of osteocytes is principally the result of disrupted blood supply rather than direct alpha ray killing. With radiothorium, concentration of alpha particles about haversian canals was sufficient to result in total plugging of the vascular tree within the haversian canals resulting in complete bone necrosis and inhibition of internal reconstruction of cortical bone. With radium and plutonium only about half of the canals are plugged, which allows internal reconstruction to proceed; however, the nature of the remodelling in this environment is abnormal (formation of large cavities and abnormal osteones). It is also suggested that both devitalization of bone and occurrence of large cavities weakens the bone which in turn results in spontaneous fracturing of long bones.

The authors are indebted to the Director of the Radiobiology Lab., Prof. T. F. Dougherty, whose cooperation facilitated this work. Technical assistance of Milton Lowe and Renon Mical is particularly appreciated.