title: Sensitization of low-dose-rate irradiation by nonlethal hyperthermia.
abstract: To assess whether hyperthermia could radiosensitize cells irradiated at a low dose rate, Chinese hamster V79 cells were simultaneously heated and irradiated at 0.86 Gy/h. The data showed that heat treatments at 39 and 40 degrees C, which did not induce heat killing alone or high-dose-rate radiosensitization, resulted in enhanced cell killing with low-dose-rate irradiation. The dose-modification factor (ratio of the slopes of the curves for low dose rate and high dose rate) was reduced to 1.8 at 39 degrees C and 1.4 at 40 degrees C, compared to a value of 2.1 at 37 degrees C. These data indicate that nonlethal heat treatments can cause enhanced radiosensitization under low-dose-rate conditions. The implications of these results for interstitial thermoradiotherapy are discussed.
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston.
authors.forename: I J
authors.initials: IJ
authors.lastname: Spiro
authors.forename: S
authors.initials: S
authors.lastname: McPherson
authors.forename: J A
authors.initials: JA
authors.lastname: Cook
authors.forename: C C
authors.initials: CC
authors.lastname: Ling
authors.forename: W
authors.initials: W
authors.lastname: DeGraff
authors.forename: J B
authors.initials: JB
authors.lastname: Mitchell
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000528:radiation effects*; D006358:Hot Temperature; D066298:In Vitro Techniques; D011836:Radiation Tolerance / Q000502:physiology*