Department of Electrical and Electronics Engineering, Middle East Technical University, Ankara, Turkey.
Phys Med Biol. 2019 May 29;64(11):115016. doi: 10.1088/1361-6560/ab1809.
Magneto-acousto-electrical tomography (MAET) is an imaging modality to image the electrical conductivity of biological tissues. It is based on electrical current induction by using ultrasound under a static magnetic field. The aim of this study is to develop a data acquisition system for MAET based on magnetic field measurements. The static magnetic field is generated by six permanent neodymium magnets. A 16-element linear phased array (LPA) transducer is utilized to generate acoustic pressure waves inside the phantom. To measure the magnetic field intensity generated by the induced currents, contactless receiver sensors are developed using two similar disk multiple layer coils, which are Helmholtz coil sensor. Physical properties and electrical characteristics of the sensors are assessed. A two-stage cascaded amplifier is designed and utilized in the receiving system. The gain of the cascaded amplifier at 1 MHz is adjusted to be 96 dB. Experimental studies are conducted with two different phantoms, having 3 S m and 58 S m electrical conductivity, respectively. A-scan and B-scan images of phantoms are obtained with the LPA transducer. Comparison of the ultrasound (A-scan) and MAET signals reveals that 3 S m conductive inhomogeneity can be detected with this data acquisition system. Furthermore, the front and rear interfaces of an inhomogeneity ([Formula: see text]) of 58 S m conductivity are detectable.
磁声电断层成像（MAET）是一种用于成像生物组织电导率的成像方式。它基于在静态磁场中使用超声波感应电流。本研究的目的是开发一种基于磁场测量的 MAET 数据采集系统。静态磁场由六个钕永久磁铁产生。利用 16 单元线性相控阵（LPA）换能器在体模内产生声压波。为了测量感应电流产生的磁场强度，使用两个类似的磁盘多层线圈开发了非接触式接收器传感器，这是亥姆霍兹线圈传感器。评估了传感器的物理性质和电气特性。在接收系统中设计并使用了两级级联放大器。在 1MHz 时，级联放大器的增益调整为 96dB。使用两个具有 3 S m 和 58 S m 电导率的不同体模进行了实验研究。使用 LPA 换能器获得了体模的 A 扫描和 B 扫描图像。对超声（A 扫描）和 MAET 信号的比较表明，该数据采集系统可以检测到 3 S m 的电导率不均匀性。此外，可以检测到 58 S m 电导率不均匀性的前后界面 ([Formula: see text])。
