[ニューロンと心筋の細胞内カルシウムに対するTETRA電磁界の影響に関する研究] med./bio.

測定および計算の詳細

In order to establish a relationship between the input power of the generic TETRA signal and the SAR in the cell culture, the exposure system (including the microscope objective) was modelled using the finite integral method code, CST Microwave Studio. The electric field strength was determined along the central line of the transmission line and the calculated field strengths were then used to determine the SAR inside the perfusion medium volume. No distinction was made between the cellular component within the perfusion medium volume and the bulk perfusion medium. Dielectric properties of the cell perfusion liquid were measured at 34°C using an open ended coaxial probe and a computer controlled network analyser in the frequency region of 130 MHz-20 GHz. Using measured values for the perfusion solution, the distribution of SAR within the perfusion fluid volume was calculated. In the vicinity of the microscope objective, where the cells were recorded, the SAR varied by ±20% across the field of view, i.e. the SAR values for an average exposure of 400 mW/kg ranged from 320-480 mW/kg. Taking into account the temperature dependence, the whole volume average SAR at 30°C was determined to be 7.88% lower, and that at 37°C 3.17% higher, than that at 34°C. The input values used for the computational modelling of the transmission line were confirmed by measurement at the National Physical Laboratory. The measurements of impedance, voltage standing wave ratio and E field were in good agreement with the computed values.