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 T-75 culture flask being irradiated within a transverse electromagnetic (TEM) cell was studied both experimentally and numerically. Direct thermal measurements of a T-75 containing 40 mL of culture medium and resting upon a 3-mm-thick slab of alumina ceramic (epsilon r = 9.6) revealed that, compared to the same flask resting upon a foam slab (epsilon 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 dose-response curves without the costs and difficulties of a fourfold increase in amplifier power. Finite-difference time-domain (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.
Pickard
W F
WF
Department of Electrical Engineering, Washington University, Saint Louis, MO 63130, USA. wfp@ee.wustl.edu
Straube
W L
WL
Moros
E G
EG
D000042:Absorption; D018929:Cell Culture Techniques / Q000379:methods*; D003198:Computer Simulation; D003626:Data Display; D004574:Electromagnetic Fields; D008954:Models, Biological; D013696:Temperature; D013821:Thermometers