[Microwave thermoacoustic signal analysis of biological tissues based on the coupling of multifield]

According to the coupling relationship of electromagnetic field, thermal field and acoustic field during the time that microwave irradiates the biological tissues, we conducted a study on the microwave-induced thermoacoustic tomography forward problem. In the study, we started from the thermoacoustic wave propagation that incorporated the spatial inhomogeneities of thermal and acoustic properties, and we used a method based on the finite element to solve the thermoacoustic equation. As the penetration depth and the specific absorption rate changed with the microwave frequency in biological tissue, the hotspot position and value altered, so the pressure wave propagation and the detecting value would be influenced. By analyzing the simulation results, we found that different detection point has different information content. Because the microwave-induced acoustic waves contain abundant information about the structural, electromagnetic and acoustic properties of phantom, they can reflect information on the tissue composition and structure of the phantom effectively.