Time-Weighted SAR in Rats for the Estimation of Practical RF Exposure in Reverberation Chambers

Herein, we present a new method for the calculation of the specific absorption rate (SAR) of rats (named time-weighted SAR) to practically consider the effect of the ever-changing movements of rats on their SARs. First, nine rats in separate cages were recorded for approximately 22 h, and the footage every 1 min was collected to obtain 1,307 still shots per rat. Next, five representative postures, which were classified according to the similarity of the still shots, were selected. Subsequently, the percentage of each posture was calculated by computing the number of still shots classified into the corresponding representative postures. Lastly, we demonstrated that although each rat exhibited relatively different and diverse movements during the observation period, the application of this percentage to the SARs of each posture resulted in very similar SAR levels among the rats. This indicates that the time-weighted SAR can be a suitable parameter for accounting for various behavior patterns of rats, as it can measure the total amount of real RF exposure more precisely and practically.