Computational design of a 3D magnetic particle imaging (MPI) prototype

Magnetic particle imaging (MPI) is an emerging imaging modality that exploits the magnetization response of magnetic nanoparticle tracers. While MPI offers substantially higher resolution compared to magnetic resonance imaging, its translation to human-scale applications remains limited. These challenges stem from the requirement of high-intensity electric currents to generate strong magnetic fields, as well as reduced field uniformity with increasing coil spacing. To overcome these barriers, comprehensive simulation studies are essential for guiding MPI prototype design and performance optimization. In this work, we present a finite element method (FEM)-based design of a three-dimensional (3D) MPI prototype. The system integrates electromagnetic coils for the selection, drive, and focus fields, along with a gradiometer configuration for signal reception. Each coil’s geometry and magnetic field were first simulated independently to validate its ability to generate the desired magnetic field and subsequently combined into a full-system design with time-domain input excitation signals. This framework achieved 3D field-free point (FFP) scanning within a 20 mm3 field of view. The selection field provided a gradient of 4, 2, and 2 T/m in z axis, y axis, and x axis, respectively, the drive field produced 20 mT, and the focus fields generated 40 mT (z-axis) and 20 mT (y-axis), enabling controlled spatial movement of the FFP. Overall, this study establishes a complete 3D FEM simulation framework for MPI system design and lays the foundation for future optimization toward clinical-scale applications.