Interaction of hyperthermia and radiation: temperature coefficient of interaction.

Cell survival data were collected to determine the survival surface for asynchronous CHO cells X-irradiated at room temperature 100 min prior to a hyperthermic exposure. The survival surface could be approximately described by a survival model comprising three components of cell killing; the unperturbed radiation component, the unperturbed hyperthermia component and the interaction component. The temperature sensitivities of the hyperthermia component and of the interaction component were investigated by using different hyperthermic temperatures, revealing that the interacting component is significantly less sensitive to a change in temperature than the unperturbed hyperthermia component.