Development of the pulse magnetic field excitation system in magnetoacoustic tomography

Magnetoacoustic tomography with magnetic induction (MAT-MI) is an imaging modality proposed for noninvasive conductivity imaging of high spatial resolution. In our work of study, an adjustable narrow pulse magnetic field excitation system based on the cascade of high speed MOSFETs is designed and applied to produce eddy current and measurable ultrasound signals in biological tissue. The transient power of the pulse can reach up to 2.7MW and the estimated eddy electrical field in the biological tissue excited by a coil is up to 1600V/M. An obvious ultrasound signal can be detected by a general ultrasound probe with an amplifier of 82dB. The coil matching circuit and the optimized pulse transformer is employed to improve the driving capability. The designing principle is discussed in our research. The tomographic result of the experiment showed the capability and reliability of the pulse excitation system.