THE RELATION OF RADIATION DOSE TO SKELETAL DAMAGE FROM BONE-SEEKING ISOTOPES
Effects of irradiation of bone from internally deposited radioisotopes are considered. Problems encountered in measurement of the absorbed radiation dose and assessing damage in bone are also considered. The calculated accumulated dose can only be approximate, and to estimate it over a long period of time a very large number of observations have to be made. Even so, measurement of absorbed radiation dose rate at any point in time is far easier to carry out than measurement of the damage caused since the effects of ionizing radiations on living tissue are so complex. To assess radiation injury in bone, crude histological criteria are still used and better methods of assessing tissue damage are needed. One of the great difficulties in the analysis of radiation damage to bone is to disentangle primary effects on the bone cells due to radiation from secondary effects due to radiation injury to blood vessels. Experimental observations suggest that, though areas of bone may be rendered avascular and the osteocytes die through radiation injury to blood vessels, radiation injures the cells of the osteogenic connective tissue directly, leading to abnormal cellular proliferation, abnormal apposition and resorption, and ultimately tumor formntion. The characteristics of damage in bone tissues which will occur within six months to a year of administration of relatively large amounts of Sr/sup 90/ are described. Detailed observations, attempting to relate absorbed radiation dose, from both Sr/sup 90/ and P/sup 32/, to damage in the long bones of rabbits and rats, are described. Also discussed is the characteristic damage seen in radium poisoning and in the bones of dial painters. Figures are given to show the extremely high dose rates and accumulated dose that may be received by bone. The question of whether tumors can arise without gross histological damage is discussed, and it is concluded that this can only be settled by histological studies and dosimetry measurements made simultaneously in animals given small amounts of radioactive bone-seeking isotopes. It is emphasized that knowledge of the relation of radiation absorbed dose to radiation damage and carcinogenesis is still very inadequate. (BBB)
- Research Organization:
- Churchill Hospital, Oxford
- NSA Number:
- NSA-18-013511
- OSTI ID:
- 4093763
- Journal Information:
- Lectures Sci. Basis Med., Journal Name: Lectures Sci. Basis Med. Vol. Vol: 9
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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