Research On Magneto-acoustic Magnetic Permeability Tomography With Magnetic Induction

Magneto-acoustic tomography with magnetic induction(MAT-MI)is a multiphysics coupled imaging technique that incorporates electrical impedance tomography and ultrasound imaging.In order to study the influence of adding magnetic nanoparticles as a contrast agent for MAT-MI on its physical process,firstly,we introduce the research background of the subject,the research status of MAT-MI and magnetic nanoparticles at home and abroad,and introducedthe principle of MAT-MI and the characteristics and preparation of magnetic nanoparticles.Further we analyze and compare the electromagnetic and acoustical properties of MAT-MI theoretically before and after adding magnetic nanoparticles,and name the imaging modes before and after the addition of magnetic nanoparticles as Magneto-acoustic Impedance Tomography with Magnetic Induction(MAIT-MI)and Magneto-acoustic Magnetic Permeability Tomography with Magnetic Induction(MAMPT-MI).Then we construct a two-dimensional planar model.Under the guidance of space-time separation theory,we determine the reasonable simulation conditions and solve the electromagnetic field and sound field physical processes in the two modes using the finite element method.The magnetic flux density,sound pressure distribution,and related one-,two-,and three-dimensional images were obtained.We make a qualitative and quantitative analysis based on the theoretical and simulation results.In addition,considering the physical properties of magnetic nanoparticles,another important factor involved in imaging,we also carry out theoretical and simulation analysis on the effects of its radius and permeability.Finally,we conduct experiments to verify the theoretical analysis and simulation results.The research results show that the peak time of the time item separated from the sound source has a corresponding relationship with the peak time of the sound pressure signal.At this moment,MAMPT-MI produces larger sound pressure signals,and the sound pressure distribution of MAMPT-MI is more uniform,which facilitates detection and completion of sound source reconstruction.The physical parameters of the magnetic nanoparticles have a certain influence on the imaging effect.In the process of preparing the magnetic nanoparticles for imaging,such factors can be considered,and the radius interval in which the imaging effect is stable is selected;the experiment verified the technical feasibility and imaging effect of MAMPT-MI is better than MAIT-MI without adding a static magnet;MAMPT-MI can removestatic magnetic fields on the device compared to MAIT-MI,which makes the experimental equipment simple and easy to operate.The research results can lay the foundation for MAT-MI of magnetically responsive nanoparticle in subsequent experiments and even clinical applications.This paper was jointly developed with Department of Engineering Electromagnetics and Applied Technology of the Institute of Electrical Engineering of the Chinese Academy of Sciences.The paper has 40 pictures,6 tables,and 116 references.