磁热声成像的实验研究

发布时间：2018-04-17 21:33

本文选题：磁热声成像 + 脉冲磁场　；参考：《高电压技术》2017年08期

【摘要】：磁热声成像(MMTAI)是一种新型的人体疾病早期检测电阻抗成像技术,融合了传统电阻抗成像高对比度和超声成像高分辨率的优势。为了验证磁热声成像针对生物组织的可行性,研究了磁热声成像的原理,并搭建了相应的实验系统。研究结果表明:将低电导率目标体置于μs级脉冲宽度的脉冲磁场中,会在目标体内产生涡流,目标体吸收焦耳热后瞬时膨胀并发出声信号,声信号含有目标体的电导率信息;利用电磁场与声场理论所推导的目标体声源计算式反映了声源与电导率之间的关系;对磁-热-声多场耦合作用下产生的热声信号进行检测和分析,再利用时间反演法重建声源分布;将含质量分数10%氯化钠的凝胶仿体模型置于μs级脉冲宽度的脉冲磁场中,采用中心频率为1 MHz的超声换能器采集超声信号,信号被放大60 d B后的峰峰值约为4 m V,利用旋转凝胶仿体采集的100组信号所重建的热声图像能反映低电导率凝胶仿体的电导率分布。此实验验证了该方法用于低电导率介质成像的可行性,为该方法用于生物组织成像的研究提供了依据。
[Abstract]:MMTAI (Magnetic Thermoacoustic Imaging) is a new electrical impedance imaging technique for early detection of human diseases, which combines the advantages of traditional electrical impedance imaging with high resolution in ultrasonic imaging.In order to verify the feasibility of magnetothermoacoustic imaging for biological tissue, the principle of magnetothermoacoustic imaging is studied, and the corresponding experimental system is built.The results show that when the low conductivity target is placed in the pulse magnetic field with the pulse width of 渭 s, the eddy current will be produced in the target body, and the target body will instantly expand after absorbing the Joule heat and send out the acoustic signal. The acoustic signal contains the conductivity information of the target body.Based on the theory of electromagnetic field and sound field, the calculating formula of target sound source reflects the relationship between sound source and conductivity, and the thermoacoustic signal generated by the coupling of magneto-thermal-acoustic field is detected and analyzed.Then the sound source distribution was reconstructed by time inversion method, the gel model containing 10% sodium chloride was placed in the pulse magnetic field with 渭 s pulse width, and the ultrasonic signal was collected by an ultrasonic transducer with a central frequency of 1 MHz.The peak value of the signal is about 4 MV after being amplified for 60 dB. The thermoacoustic images reconstructed by 100 sets of signals collected by rotating gel imitating body can reflect the conductivity distribution of the low conductivity gel imitating body.This experiment verifies the feasibility of using this method in low conductivity medium imaging, and provides a basis for the study of biological tissue imaging using this method.
【作者单位】：中国科学院电工研究所;中国科学院大学;
【基金】：国家自然科学基金(51477161;61427806;51137004)~~
【分类号】：TB559

【相似文献】