ABSTRACT
Enhancement of radiation-induced cell lethality goes hand in hand with enhancement of the damage to DNA. The fact that cellular damage leading to cell death induced by heat is different from that induced by irradiation explains why cells that are quite radioresistant may be rather sensitive to heat treatment. Much data on the enhancement of radiation effects by heat treatment come from work with mammalian cells cultured in vitro. Thermal enhancement is largest when cells are irradiated during heat treatment. However, thermal enhancement is hardly impaired when heat is applied either immediately before or after irradiation. Variation in the sequence of application may lead to slight variations in enhancement, which however, may differ with the cell line used in the experiments. Thermotolerance is a phenomenon which emerges in fractionated treatment of cells by hyperthermia or in a single treatment at temperatures below 43°C.
