Experimental Study On Imaging With Current Exciting Based On Magneto-acoustic Effect

For a long time, study on the electrical characteristics of biological tissue aroused attentions from experts in the field. Research shows that not only large differences existed in electrical characteristics of biological tissue, but also the electrical characteristics of tissues and organs varied with functional condition and diversification, thus, the electrical characteristics of imaging can reflect the human physiological and pathological conditions. Non-destructive detection can diagnose the electrical characteristics of biological tissue.Imaging with current exciting based on magneto-acoustic effect is a method of non-destructive detection for the electrical characteristics of tissue. The phantom was placed in a static magnetic field while microsecond pulse were imposed on the phantom, and thus the acoustic response signal was generated by magneto-acoustic effect, meanwhile, acoustic signals were detected by the transducer around the object to reflect the electrical characteristics information within the tissue.In this study, we established simple model and conducted simulation and experimental study based on magneto-acoustic effect. In the simulation study, we established models such as circular coil, concentric coil, wafer with hole. The acoustic pressure was calculated based on the current distribution by means of the finite element analysis software.In the experimental study, we discussed the magnetic acoustic signal generated by different excitation pulse in the experiment, sinusoidal signal was selected for the excitation current waveform. While the transducer was placed in one position at different angles, signal intensity picked by the transducer was varied. The signal is relatively weak while the transducer was rotated to a certain angle. Experimental results of different shape models indicated that the magneto-acoustic coupling effect could be used in electrical characteristics imaging of the tissue. Also, the gel phantom with similar electrical characteristics to the biological tissue was detected in the experiment, the acoustic signal aroused in gel phantom was weak, but it could reflect the sample boundary information. The frequency of exciting current signal is1MHz, and it could effectively avoid the interference of the external low-frequency noise. The signal has high signal to noise ratio. In the imaging experimental study, acoustic signal data was collected while rotating the transducer, and moving the transducer in circle. As a result, images by direct back projection reconstruction could reflect the basic shape of the sample.In conclusion, the acoustic signal was detected in different models, and the primary reconstruction imaging was obtained a favorable effect, which is important for the deeper magneto-acoustic coupling study.