ASSESSMENT OF SAR DISTRIBUTIONS INSIDE 10, AND 70 DAYS OLD RATS EXPOSED TO 900MHZ RF Y. Alfadhl, C.C.Chiau,

Accurate determination of the specific absorption rate (SAR) is an important aspect in understanding the interaction between electromagnetic fields (EMF) and living matter. Influences due to dielectric properties, shape, and size of the exposed tissues have been considered to play an important role in the determination of SAR distributions in anatomical rat models [1-2]. Direction and polarisation of exposure were also considered to produce some effect on the SAR values. In order to highlight the effects of the dielectric properties of tissues on SAR values, we compute and compare the SAR distributions of anatomical rat models at different ages. Finite Difference Time Domain (FDTD) technique is used to simulate the models due to its ability to apply Maxwell’s curl equations for solving complex microwave problems with reasonable computation requirements [3-5]. Complex FDTD rat models are created in the form of discrete voxels within a space region, based on Magnetic Resonance Imaging (MRI) scans of actual rats. The MRI scans are converted into the FDTD grid structure with 34 different tissue types [6]. Different rat age models are accomplished by resizing the original FDTD model diminutions (voxel sizes) and changing the their dielectric properties according to those measured and published in literature [7]. A FDTD code (used in Gajsek study [1]) is used to assess the amount of energy absorbed by the geometrically complex biological models during RF exposure. This code is used to predict localised and whole -body normalised SAR values (W/Kg per mW/cm2). SAR distributions inside the rat models are calculated by computing the local electric field strengths inside each given tissue type, and feeding these values into equation (1) below: