High-power active interference suppression in magnetic particle imaging

For angiography, stem cell imaging, and cancer imaging, magnetic particle imaging (MPI) can replace conventional techniques due to its safety in vivo, exquisite image contrast, and high detection sensitivity. However, compared to the theoretical physical sensitivity limit of a MPI scanner with 1 mm3 resolution using image 17 nm iron oxide nanoparticles, which lies between 100 nM and 1 μM1, the detection sensitivity for current MPI systems is worse by over 4 orders of magnitude. Factors contributing to this lack of sensitivity include non-optimal noise matching and feedthrough interference, of which the latter is a more dominant effect due to spectral overlap between the interfering signals and particle signals. Gleich et al., Schmale et al. and the authors of this study have previously attempted to decrease the interference through high-power filters and reducing capacitor distortion. In this work, we attempt to actively cancel interfering magnetic fields through the use of a feedforward transformer coupling circuit.