Biological Effects by Microwaves

Domestic and industrial applications of microwaves are everyday extended implying protection conditions and safety standards which require a better knowledge of biological effects associated with microwave radiations. Interactions of microwaves with living systems are reviewed on the basis of levels of organization which may be molecular, unicellular and pluricellular. Among a large number of publications, those giving correlated experimental observations at low or medium power density or associated to frequency dependent effects are particularly examined. Results are still insufficient for establishing permissible exposure levels lower than that derived from thermal biological effects. These thermal effects are now being studied as the induction of hyperthermia in living tissues, for instance, as an adjunct to the cancer treatment.