Three-dimensional model of conductivity imaging for magneto-acousto-electrical tomography

摘要

This article presents a series of three-dimensional results for Magneto-acousto-electrical Tomography (MAET), which is a hybrid imaging modality combining the merits of high contrast and high resolution. The ultrasound field and electromagnetic field are coupled to generate current density distribution inside the sample. However, three-dimensional images have not yet been realized for MAET through voltage signals detected by electrodes. In this paper, the mathematical model of MAET is analyzed, and a new image reconstruction scheme is proposed, which is verified by a numerical framework. One three-dimensional numerical model of normal and tumor tissues is formed to analyze the multiphysics problems. In the model, vibration velocity is obtained for pulse type ultrasound excitations with the duration of 0.5 μs. The static magnetic field produced by two permanent magnets is about 300 mT. In order to measure the voltage caused by the MAET effect, two electrodes are attached on the surface of the sample. A series of MAET signals are obtained when the transducer locates in different positions. The distribution of three-dimensional conductivity is recovered by the new image reconstruction scheme. The reconstructed conductivity images are consistent with the original distribution, thus verifying the effectiveness of the new image reconstruction scheme. In addition, the experiment has also validated the mathematical model and simulation results. The simulation and the experimental results indicate that the MAET has the potential to become a new tool to study the electrical properties of tumors in humans.