ABSTRACT
Radiofrequency (RF) radiation or microwaves (MW) induce a variety of biological and health effects that are usually classified into thermal and nonthermal (NT) effects. The role of exposure duration and dose in assessing the NT MW effects has been analyzed by many research groups using various endpoints. Laboratory in vitro studies, animal in vivo studies, and human studies were performed. This chapter provides a survey of studies, which evaluate the dependence of the NT MW effects on exposure duration and dose. In some studies, prolonged MW exposures were associated with less prominent effects than shorter exposure. Epidemiologic studies have consistently shown an increase in brain cancer risks at prolonged duration of exposure to mobile phones while the risks are significantly lower at shorter durations. Prolonged exposure to NT MW from mobile communication correlated with increased cancer risk. While the dose rate/SAR concept is adequate for description of acute thermal effects, it is not applicable for chronic exposures to NT MW.
