Experimental and numerical determination of SAR distributions within culture flasks in a dielectric loaded radial transmission line

The effect of dielectric loading on the cell layer specific absorption rate (SAR) within a T75 culture flask being irradiated within a transverse electromagnetic (TEM) cell was studied both experimentally and numerically. Direct thermal measurements of a T75 containing 40 m L of culture medium and resting upon a 3mmthick slab of alumina ceramic (ε_r = 9.6) revealed that, compared to the same flask resting upon a foam slab (ε_r = 1.0) of the same thickness, the average SAR at the cell layer was increased roughly fourfold. This fourfold increase is significant experimentally because it allows biologists to perform experiments over a larger range of SAR values needed to determine possible doseresponse curves without the costs and difficulties of a fourfold increase in amplifier power. Finitedifference timedomain (FDTD) simulations of the SAR distribution were in good quantitative agreement with the experimental measurements. It is concluded that FDTD modeling can be a cost effective and scientifically acceptable means of obviating the thermal measurement of SAR.