Magnetoacoustic concentration tomograghy of magnetic nanoparticles (MNPs) with magnetic induction (MACT-MI) is a multi-physics field imaging method based on the coupling effect of magnetic field and acoustic field. In order to generate a gradient magnetic field with higher uniformity by using lower current excitation, this paper takes the magnetic field gradient of 0.3 T/m as the design objective and utilizes the Beetle Antennae Search Algorithm to optimize the parameters of the excitation

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... nt of multiple coils. The uniformity of gradient magnetic field generated by four typical six-coils structures with different radii and distances was compared with that generated by the Maxwell coil, and then the optimal structure of six-coils was determined. By using the finite element method, the physical process of MACT-MI was numerically solved according to the optimization results, and we obtained the one-dimensional and two-dimensional distribution images of magnetic force and sound pressure. The results show that compared with the Maxwell coil, the multi-coil structure can effectively reduce the current excitation and provide a higher uniform gradient magnetic field, which makes the magnetic force of MNPs more uniform and promotes the complete reconstruction of the sound source. These research results can provide research ideas for the optimization of MACT-MI system and lay a foundation for subsequent experiments and even clinical practice.