Acute Dosimetry and Estimation of Threshold-Inducing Behavioral Signs of Thermal Stress in Rabbits at 2.45-GHz Microwave Exposure

In the current international guidelines and standards for human exposure to microwaves (MWs), the basic restriction is determined by the whole-body average specific absorption rate (SAR). The basis for the guidelines is the adverse effect such as work stoppage in animals for whole-body average SARs above a certain level. Although it is known that absorbed MW energy causes the behavioral sign of thermal stress, the relationship of whole-body average SAR with temperature/temperature elevation has not been sufficiently investigated. In the present study, we performed experiments on rabbits exposed to 2.45-GHz MWs. A total of 24 measurements were conducted for power densities from approximately 100 to 1000 W/m
²
. Our computational code for electromagnetic-thermal dosimetry was used to set the exposure time duration and incident power density. Our experimental results suggest that a core temperature elevation of 1 °C is an estimate of the threshold-inducing complex behavioral signs of MW-induced thermal stress in rabbits for different whole-body average SARs and exposure time durations. The whole-body average SAR required for MW-induced behavioral sign in rabbits was estimated as approximately 1.3 W/kg for 2.45-GHz MWs.