Spatial selectivity enhancement in magnetic fluid hyperthermia by magnetic flux confinement

Aiming to increase spatial selectivity to enhance the precision in Magnetic Fluid Hyperthermia (MFH) therapy and the spatial resolution in imaging, we propose a strategy to increase the selection field gradient in Magnetic Particle Imaging (MPI). In this study, a solution for an existing MPI system topology was simulated, using an additional soft magnetic material as iron core retrofit at the center of the selection field coil. Due to the core's high magnetic permeability relative to air, the magnetic flux is confined, increasing the selection field gradient. Within this simulation study, the optimal core position is evaluated, whilst its effects on the magnet system are validated. According to our results, this strategy can achieve a 27 % reduction in theranostic field of therapy. We found that this technique increases the magnetic field gradient up to a factor of 1.4 (from 2.5 to 3.4 T/m) in z-direction, without significant loading of the drive field resonance circuit caused by eddy currents in the MPI compatible iron core shielding.   Int. J. Mag. Part. Imag. 7(1), 2021, Article ID: 2103002, DOI: 10.18416/IJMPI.2021.210300