Nonuniform exposures of Petri dish cultures within a TEM cell identified by FDTD modeling

The effects of electromagnetic fields on living cell cultures have been investigated for some time. Transverse electromagnetic (TEM) transmission cells are widely used for exposing cell cultures to uniform TEM fields and quantifying the biological effects. The uniformity of exposure is critical to quantifying the response versus dose of any observed biological effect. Standing waves and other electromagnetic field nonuniformities can lead to a nonuniform exposure. The use of field or temperature probes to monitor exposure within the cell culture is not easy. First, the presence of measurement probes perturbs the field distribution. Second, the heat diffusion process is fast, especially within small cell culture Petri dishes. The finite-difference time-domain (FDTD) method provides a highly accurate means for quantifying electromagnetic field exposure levels within the culture cells. Further, given the FDTD-computed electric and magnetic field distribution throughout the TEM cell, the specific absorption rate (SAR) can be calculated at each grid point within the cell culture.