Histological Changes in the Rat Bone after Varying Doses of X rays with Particular Reference to Bone Tumour Production

Abstract

The histological changes and the production of bone tumours have been studied in the hind limbs of some 257 rats after doses of X rays of 500 to 3,000 R. In some cases the 3,000 R was divided into three doses of 1,000 R or 6 doses of 500 R. The greatest number of tumors was found in the highest dosage groups, though with 500 R there was one bone tumor. The epiphyseal plate showed marked changes including transverse "splitting". Peritrabecular fibrosis only occurred in the 3,000 R group and there was no evidence to connect either this change or epiphyseal plate changes with the subsequent development of tumors. It is suggested that 2 different mechanisms may be operating in the single and fractionated dosage groups.