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Name of experiment：application of magnetoacoustic imaging method based on low frequency magnetic excitation and active ultrasonic detection in power amplifier

Research direction：ultrasonic detection

Content of experiment：In order to detect early malignant tumors, this experiment proposes a magneto-acoustic imaging method based on low-frequency magnetic excitation and active ultrasonic detection, and introduces color Doppler imaging technology to detect tissue vibration caused by Lorentz force. Active detection can use low-frequency signals as excitation, greatly improving the energy conversion rate.

Test equipment：signal generator, ATA-3090 power amplifier, ultrasonic probe, Helmholtz coil, data acquisition platform, etc.

Experimental process：

1.The construction of experimental platform

Signal excitation and the amplification module

An arbitrary waveform generator is used to generate a section of excitation signal, which is amplified by the power amplifier to generate the excitation magnetic field in the input coil. At the same time, the imitation body is placed in the excitation magnetic field, and a static magnetic field of the same direction is added to the excitation magnetic field. Under the action of the excitation magnetic field, the induced eddy current will be generated at the boundary of the region with the conductivity difference in the imitation. The induced eddy current will be further affected by the Lorentz force in the static magnetic field, and then drive the surrounding tissue to vibrate.

2.The experimental simulators were made and combined with the experimental simulators to carry out the excitation shear wave experiment.

Result of experiment:

①Curve of velocity at different points of blank imitation velocity map with time.

②Velocity curve of copper-embedded imitation at different points with time.

Conclusion of experiment ：

Combined with the experimental results of copper-embedded imitation and blank imitation in the new magnetoacoustic platform, the simulation results are further verified, and the shear wave transmission process in the simulation results is observed, which requires our experimental platform to provide stronger magnetic field to get stronger magnetoacoustic signal. The velocity and morphology information in the process of shear wave transmission are also helpful for further reconstruction of tissue conductivity distribution or tissue elasticity distribution.

Amplifier's role in this experiment：amplify the signal, generate an excitation magnetic field in the input coil.