Combined effects of hyperthermia and radiation in cultured mammalian cells
Hyperthermia (temperatures of 39/sup 0/C or higher) enhances the killing of mammalian cells by ionizing radiation (fission-spectrum neutrons and x-rays). The nature and the magnitude of the enhanced radiation killing varies with temperature and for a fixed temperature during irradiation, the enhanced lethality varies inversely with dose rate. For temperatures up to 41/sup 0/C, dose fractionation measurements indicate that hyperthermia inhibits the repair of sublethal damage. At higher temperatures, the expression of potentially lethal damage is enhanced. Since the effect of heat is greatest in cells irradiated during DNA synthesis, the radiation age-response pattern is flattened by hyperthermia. In addition to the enhanced cell killing described above, three other features of the effect of hyperthermia are important in connection with the radiation treatment of cancer. The first is that heat selectively sensitizes S-phase cells to radiation. The second is that it takes radiation survivors 10 to 20 hrs after a modest heat treatment to recover their ability to repair sublethal damage. And the third is that hyperthermia reduces the magnitude of the oxygen enhancement ratio. Thus, heat if applied selectively, could significantly increase the margin of damage between tumors and normal tissues.
- Research Organization:
- Argonne National Lab., IL (USA)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 7312110
- Report Number(s):
- CONF-770637-1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
BARYONS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CELL CULTURES
CELL CYCLE
CELL KILLING
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
FERMIONS
FISSION NEUTRONS
HADRONS
HIGH TEMPERATURE
IONIZING RADIATIONS
NEUTRONS
NUCLEONS
RADIATION EFFECTS
RADIATIONS
SYNERGISM
TUMOR CELLS
X RADIATION