Simulation Study on Forward Problem of Magnetoacoustic Tomography With Magnetic Induction Based on Magnetic Nanoparticles

Abstract

Magnetoacoustic tomography with magnetic induction (MAT-MI) is a multiphysics imaging technique that combines electrical impedance imaging with ultrasound imaging. In order to study the influence of parameters on the source of MAT-MI, such as radius and permeability of magnetic nanoparticle clusters, the paper is divided into the following stages. Firstly, this paper analyzes the electromagnetic and acoustic properties of MAT-MI after adding magnetic nanoparticles. Secondly, to determine suitable simulation conditions, a two-dimensional model is constructed. Thirdly, use the finite element method to solve physical processes of electromagnetic field and acoustic field under conditions of different magnetic nanoparticle clusters' radii and permeabilities, then obtain the magnetic flux density image. Consequently, make the qualitative and quantitative analysis according to the theory and simulation results. The results show that magnetic nanoparticle clusters interact with each other and distort the magnetic field to different degrees; its radius increases with the degree of flux density distortion around it, so does its permeability and magnetoacoustic signal intensity. The research results can play a guiding role in the parameter selection of magnetic nanoparticle clusters in practical applications to a certain extent.

Detailed Analytical Approach to Solve the Magnetoacoustic Tomography with Magnetic Induction (MAT-MI) Problem for Three-Layer Objects

“…The electric field and the eddy current density vectors inside the object can be described as follows [2][3][4][6][7][8][11][12][13][14][15][16][17]:…”

“…In case of a sufficiently short pulse, after splitting the temporary magnetic field for the functions of space and time, the Lorentz force density can be expressed as [2][3][4][6][7][8][11][12][13][14][15][16][17]:…”

“…In principle, the inverse problem can be split into two main steps. First, the references term ∇•( J × B0) of The electric field and the eddy current density vectors inside the object can be described as follows [2][3][4][6][7][8][11][12][13][14][15][16][17]:…”

“…However, the occurrence of this physics phenomena still require careful scientific study in a quantitative way [11][12][13]. In particular, analytical and numerical calculations can provide new and important information about the nature of the electromagnetic-acoustic phenomenon [14][15][16][17][18][19]. The literature on the subject is extensive and the cited references should only be treated as representative examples.…”

“…This problem has never been fully considered in the past, as in this article. Although similar problems were analyzed, either the authors did not quantify the details of eddy currents and Lorentz forces, or the objects' shapes or number of layers were different [6,8,9,[11][12][13][14][15][16][17][18][19]21,22,25].…”