电流注入式磁声耦合成像技术仿真研究

Simulation research on magneto-acoustic tomography with current injection

目的:电流注入式磁声耦合成像技术是一种新型的生物组织电特性工程成像方法,具有高分辨率和高对比度的优点。探讨电流注入式磁声耦合成像的工作原理,为成像系统实验平台的设计提供理论参考,为真实生物组织电导率的成像奠定基础。方法:结合电场、磁场、超声耦合理论,运用有限元建模分析软件COMSOL Multiphysics建立电导率仿体模型,并进行电磁场分析,获得电导率仿体的电流密度分布。利用数学工具Matlab获得磁声成像声场分布,进而重建仿体模型声源。结果:从电磁场分析结果获知电导率的分布反映了仿体模型的结构形状,电流场为一无旋场,重建的声源图像精确地反映了仿体模型电导率的分布,与仿体模型的层析结构形状、尺寸高度一致。结论:电流注入式磁声成像为组织电阻抗分布的重建提供了一种新的方法,该进一步研究磁声耦合成像的理论与实验打下了基础。

Objective Magneto-acoustic tomography with current injection （MAT-CI） is a new electrical characteristic imaging method of biological tissue, with the advantages of high spatial resolution and good contrast. The principle of MAT- CI is studied to provide a theoretical reference for designing the imaging system experimental platform and imaging the conductivity of real biological tissues. Methods Combined with the coupling theory of electric, magnetic and ultrasonic fields, the conductivity phantom model was established and the electromagnetic field was analyzed by using the finite element analysis software COMSOL Multiphysics to obtain the current density distribution of the conductivity phantom. The acoustic source of the phantom model was reconstructed based on the distributions of ultrasonic field which were obtained by using Matlab. Results The electromagnetic field analysis results showed the conductivity distribution accurately reflected the structure of the phantom model, and that the current field was an irrotational field. The reconstructed image of acoustic source accurately reflected the conductivity distribution of the phantom model, and the image was highly consistent with the topographic shape and size of the phantom model. Conclusion MAT-CI provides a new method to reconstruct the conductivity distribution of biological tissue, laying the foundation for the further study on the theory and experiment of MAT.