The extended boundary condition method approach for electromagnetic field penetration problems in magnetic resonance imaging.

摘要

In this thesis we implemented the Extended Boundary Condition Approach as a new technique to study electromagnetic problems related to Magnetic Resonance Imaging (MRI). We developed a computer code that can handle non-homogeneous scatterer, of various shapes. This kind of system is relevant to MRI, because it can model tissue configurations such as liver inside the abdomen or tumor inside the brain.;We apply our algorithm to the study of the electric field inside the scatterer and the specific absorption rate (SAR) for different configuration. The configuration that we considered is made of two non-concentric objects, one completely embedded inside the other, to mimic a tumor inside the brain. The outer layer is kept fixed. We change the size, eccentricity, and corrugation of the inner one.;We found that those parameters do not affect significantly the SAR, but we also found that SAR has a strong dependence on the system frequency. We also present results for the magnitude of the electric field for the different configurations.