Response of mouse lung to irradiation at different dose-rates
Groups of LAF1 mice were given thoracic irradiation using /sup 60/Co ..gamma..-rays at dose-rates of 0.05 Gy/min (LDR) or 1.1 Gy/min (HDR) and the death of the animals was monitored as a function of time. It was found that the time pattern of animal deaths was similar for the two different dose-rates. Dose response curves for animals dying at various times up to 500 days after irradiation were calculated and the LD/sub 50/ values determined. The curves for the LD/sub 50/ values, plotted as a function of the time at analysis for treatment at HDR or LDR, were essentially parallel to each other but separated by a factor (LDR/HDR) of about 1.8. This indicates that the sparing effect of LDR treatment is the same for deaths occurring during the early pneumonitis phase or during the late fibrotic phase of lung damage. The available information on the response of patients to whole thoracic irradiation, given for either palliation or piror to bone marrow transplantation, suggests that for similar dose-rates to those studied here the ratio (LDR/HDR) is only 1.2 to 1.3. This difference between the animal and human data may reflect the modifying effect of the large doses of cytotoxic drugs used in combination with the irradiation of bone marrow transplant patients.
- Research Organization:
- Princess Margaret Hospital, Toronto, Ontario
- OSTI ID:
- 5661690
- Journal Information:
- Int. J. Radiat. Oncol., Biol. Phys.; (United States), Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States) Vol. 9:7; ISSN IOBPD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
560152* -- Radiation Effects on Animals-- Animals
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BODY
COBALT 60
COBALT ISOTOPES
DOSE RATES
DOSES
ELECTROMAGNETIC RADIATION
FIBROSIS
GAMMA RADIATION
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LETHAL DOSES
LETHAL RADIATION DOSE
LUNGS
MAMMALS
MICE
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANS
PATHOLOGICAL CHANGES
PNEUMONITIS
RADIATION DOSES
RADIATION EFFECTS
RADIATIONS
RADIOINDUCTION
RADIOISOTOPES
RESPIRATORY SYSTEM
RODENTS
VERTEBRATES
YEARS LIVING RADIOISOTOPES