高电压技术2017，Vol.43Issue(8)：2518-2523,6.DOI:10.13336/j.1003-6520.hve.20170731011
磁热声成像的实验研究
Experimental Study of Magnetically Mediated Thermoacoustic Imaging
摘要
Abstract
Magnetically mediated thermoacoustic imaging (MMTAI) is a novel electrical impedance tomography for early detection of human diseases,which combines the advantages of high contrast of the classic electrical impedance tomography with the high spatial resolution of sonography.In order to verify the feasibility of magnetically mediated thermoacoustic imaging for biological tissues,the principle of magnetically mediated thermoacoustic imaging was studied and the experimental system was established.The study results demonstrate that when a microsecond width pulse magnetic field is applied to an object,the object absorbs Joule heating and causes heat expansion due to the effect of induced eddy current in the object.The ultrasonic signals are sent out,which involves the conductivity information of the object.Based on the theories of electromagnetic field and acoustic field,the calculation formula of acoustic source was deduced,which revealed the relationship between acoustic source and conductivity of the object.Thermoacoustic signals produced under the action of the magneto-thermos-acoustic multi fields were detected and analyzed to reconstruct the acoustic source distribution by time reversal algorithm.The gel phantom model with the mass fraction of 10％ sodium chloride was placed in the microsecond width pulse magnetic field,which caused thermoacoustic signals.After the signals were detected by ultrasonic transducer with the center frequency of 1 MHz and amplified by 60 dB,the peak value of the signals was about 4 mV.The reconstructed thermoacoustic image using 100 sets of data,which were acquired by rotating the gel phantom,could reflect the conductivity distribution of the low conductivity gel phantom.The experiments verifiy that the method for low conductivity medium imaging possesses the feasibility,and provides a basis for its potential applications to imaging in biological tissues.关键词
磁热声成像/脉冲磁场/波动方程/时间反演法/凝胶仿体/热声信号/声源重建Key words
magnetically mediated thermoacoustic imaging/pulse magnetic field/wave equation/time reversal algorithm/gel phantom/thermoacoustic signal/acoustic source reconstruction引用本文复制引用
杨延菊,李艳红,刘国强,夏慧,夏正武..磁热声成像的实验研究[J].高电压技术,2017,43(8):2518-2523,6.基金项目
国家自然科学基金(51477161 （）
61427806 （）
51137004).Project supported by National Natural Science Foundation of China (51477161,61427806,51137004). （51477161,61427806,51137004）
