感应式磁声成像中的磁热声效应研究  

Study on Thermo-Acoustic Effect in Magneto-Acoustic Tomography with Magnetic Induction

作　　者：杨铭 马任[1] 张顺起[1] 周晓青[1] 殷涛[1] 刘志朋[1] Yang Ming;Ma Ren;Zhang Shunqi;Zhou Xiaoqing;Yin Tao;Liu Zhipeng(Institute of Biomedical Engineering,Chinese Academy of Medical Sciences&Peking Union Medical College,Tianjin 300192,China)

机构地区：[1]中国医学科学院北京协和医学院生物医学工程研究所,天津300192

出　　处：《中国生物医学工程学报》2020年第3期295-302,共8页Chinese Journal of Biomedical Engineering

基　　金：国家自然科学基金(81772004,61701545);天津市自然科学基金(#17JCZDJC32400)。

摘　　要：探究感应式磁声成像中的磁热声效应,分析磁声声源与热声声源分布及幅值特征。建立磁声及热声声源表达式,数值仿真多层电导率仿真模型的感应电流分布、磁声+热声声源分布及声压信号,对两种声源分布及重建结果进行比较。为验证仿真结果,建立磁声成像实验平台,采用导电橡胶圈仿体分别开展磁声和热声圆周扫描实验,并对磁声和热声信号幅值和声源重建结果进行比较分析。仿真结果表明,磁声声源分布集中在电导率边界处,而热声声源分布展宽,并且在边界和内部均有分布;磁声声源的最大值是热声声源的15倍。实验结果表明,热声声压信号峰-峰值是混合信号的1/4。热声信号重建的声源图像在边界处更模糊,磁声信号的声源重建图像边界清晰但存在伪影。仿真和实验结果均证明,磁声成像中同时存在热声效应。从热声声源的分布及热声信号与磁声信号的幅值关系中可见,热声效应在一定程度上会对磁声成像结果产生影响。The aim of this paper was to investigate the thermo-acoustic(TA)effect in magneto-acoustic tomography with magnetic induction(MAT-MI)and analyze the characteristics of distribution and amplitude of magneto-acoustic(MA)source and thermo-acoustic source.Expressions of MA and TA sources were established.The induced current distribution,MA+TA source distribution and sound pressure of the multi-layer conductivity simulation model were calculated by numerical simulation.The results of the two kinds of source distribution and reconstruction were compared.To verify the simulation model,MAT experimental platform was built,and the experiments of MA and TA were carried out with a conductive rubber ring.The amplitude and reconstruction results of MA and TA signals were compared and analyzed.Numerical simulation showed that MA source concentrated at the conductivity boundary,while TA source was widely distributed at both the boundary and the inside.The maximum value of MA source was 15 times of TA source.Phantom experiments showed that the peak to peak value of TA signal was a quarter of mixed signal.The reconstructed boundary of TA was fuzzy,while that of MA was clear but contained artifacts.The results of simulation and experiment proved that TA effect existed in MAT.The distribution of TA source and the amplitude relationship between MA and TA signals suggested that TA effect partly affected the result of MAT.

关 键 词：感应式磁声成像 热声效应 焦耳热 声源分布 声源重建 

分 类 号：R318[医药卫生—生物医学工程]