基于真实乳腺模型的感应式磁声成像正问题

摘要

Magnetoacoustic tomography with magnetic induction (MAT-MI) is a new type of multi-physical, functional imaging modality, which combines the electrical impedance tomography with the sonography. Due to the complex structure, the MAT-MI imaging problems based on real model is of scientific and clinical significance. Wherein, the forward solver is the foundation of MAT-MI imaging. This paper addressed the problem for the modeling and forward solution of MAT-MI. The principle of coupling problem in MAT-MI was analyzed, and the real model of breast was reconstructed. Using generalized finite element method (GFEM), the forward problems of electromagnetic field and acoustic field were solved based on the real model of breast. The distributions of the acoustic source and acoustic pressure were obtained. The results show that in the real model, the distributions of the eddy current density and the acoustic source, as well as the profile of the acoustic pressure, changed remarkably, compared with the ideal two-layer concentric spheres model. It is suggested that the effects of the real model should be taken into account for image reconstruction in clinical application. Thanks to the high accuracy, the calculation method in this paper is applicable to solve the forward problem of MAT-MI.%感应式磁声成像（MAT-MI）是一种融合电阻抗成像和超声成像的多物理场成像技术。生物体结构复杂，对生物体 MAT-MI研究具有重要意义和临床应用价值。正问题计算是 MAT-MI的前提和基础，以MAT-MI建模与正问题求解为研究对象，分析了MAT-MI中磁声耦合问题的原理，构建了真实乳腺模型；利用广义有限元法求解了电磁场和声场正问题，获取了声源、声压分布，并对计算结果进行了误差分析。结果表明：真实模型与理想同心球模型相比，涡流密度和声源的分布、声压均发生了较大变化，在临床应用的图像重建中应予以足够重视。该计算方法可适用于真实模型MAT-MI正问题的求解，计算精度较高。