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

Abstract

After an extensive latent period plutonium, radiothorium and radium in cortical bone caused plugging in haversian canals which in turn resulted in bone necrosis. A vascular injection 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 caused total plugging of the vascular tree within the haversian canals with 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.