Forward Research on Magneto-acoustic Imaging in Frequency Domain based on Continuous Wave
ZHANG Shunqi;ZHOU Xiaoqing;YIN Tao;LIU Zhipeng;Institute of Biomedical Engineering,Chinese Academy of Medical Sciences & Peking Union Medical College;
The common time domain processing method in magneto- acoustic tomography( MAT) is disturbed by the high frequency stimulated pulse in space,which can limit the image quality. A new frequency domain measuring and processing method to detect the weak signal of MAT by using lock- in technique was introduced and studied in this project. The mathematics model was established. The simple conductivity edge model of simulations and experiments detecting based on sinusoidal excitation were conducted to validate the theory. Simulating results showed that the conductivity information was contained in the frequency signal based on the frequency domain MAT imaging method. Experiment results were in accord with the simulating results. Also,the precision of the frequency method could achieve 10- 7Pa,and the stimulating current could be smaller than 1 m A. In conclution,the proposed frequency MAT method may be helpful to improve the measurement precision,and realize higher resolution by using low frequency excitation. It would be significative to measure the inner conductivity of the medium.