EFFECTS OF DOSE-RATE AND PROTRACTION: A SYMPOSIUM. I. PATTERNS OF RESPONSE TO WHOLE-BODY IRRADIATION: THE EFFECT OF DOSE INTENSITY AND EXPOSURE TIME ON DURATION OF LIFE AND TUMOUR PRODUCTION
The lethal effects and functional deficiencies produced by continued daily whole-body irradiation appear to show two distinct patterns of response. Differences in doseintensity of the radiation exposure and in LET of the type of radiation do not seem to be important when the biological damage may be plausibly interpreted as depending on cell depletion. Where re-population of irradiated tissues can occur as a consequence of cell division, adaptation to continued irradiation regularly occurs, i.e., in spite of continuing injury, damage is not progressive but reaches a steady sttae. Damage is then dependent on average dose- rate rather than on total dose, and differences of a few-fold in average dose- rate may change the degree of damage from gross to barely measurable. Increasing the over-all exposure time during which a fixed total dose is given always reduces the effect. A contrasting pattern of response is shown in the induction of murine leukemia, and also in shortening of life, since the degree of life- shortening and the shape of the mortality curve after limited periods of daily irradiation by x rays, gamma rays or fast neutrons, was found to depend markedly on the amount of leukemia produced. Increasing the over-all exposure time may increase the effect of a given total dose, and the doseintensity of the individual radiation exposures may be quantitutively important. There is also a markedly curvilinear relation between dose and response. (auth)
- Research Organization:
- Atomic Energy Research Establishment, Harwell, Berks, Eng.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-13-021852
- OSTI ID:
- 4231118
- Journal Information:
- Brit. J. Radiol., Vol. Vol: 32; Other Information: Orig. Receipt Date: 31-DEC-59
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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