Uncertainty evaluation of dosimetry due to plastic holder for restraining small animal in in vivo near field exposure setup

In most in vivo exposure setups for testing biological effects of cellular telephones on a small animal, a plastic holder is commonly used for restraining the small animal in order to keep a constant near-field exposure. Although the plastic holder should affect the specific absorption rate (SAR) in the small animal, few researchers have considered its influence in their exposure setup design or dosimetry evaluation. We previously developed an in vivo exposure setup for testing the promoting effect of digital cellular telephones on mouse skin carcinogenesis. In this paper, the influence of a plastic holder for restraining the mouse in the exposure setup was investigated numerically and experimentally. The numerical investigation was conducted by using the finite-difference time-domain (FDTD) method together with a realistically shaped mouse model. The validity of the FDTD modeling was verified by the antenna impedance measurement. As a result, an increase of 18% on the peak SAR was found due to the presence of the mouse holder.