In medicine, therapeutic hyperthermia (Greek overheating) is a treatment in which the temperature of the body tissue is artificially increased. It is a part of thermotherapy. There is overheating of the whole body and that of regions or individual organs. The term does not include simple external heat applications, which primarily raise the temperature of the skin layers (fango, infrared treatment), etc.
In contrast to fever therapy, overheating therapy artificially restricts the body's heat output, for example through baths or heat-accumulating wraps. Basically, hyperthermia refers to all those procedures in which the body or tumor area is overheated by micro- or radio waves or by infrared radiation from the outside.
Source: Wikipedia