Active Cancellation of Direct Feedthrough Enables 100-fold More Sensitive Mass-Limited Detection in Magnetic Particle Sensing Systems.

Magnetic particle imaging (MPI) is a tracer imaging modality that detects superparamagnetic iron oxide nanoparticles (SPIOs), enabling sensitive, radiation-free imaging of cells and disease pathologies. The arbitrary waveform relaxometer (AWR) is an indispensable platform for developing magnetic nanoparticle tracers and evaluating tracer performance for magnetic particle imaging applications. One of the biggest challenges in arbitrary waveform excitation is direct feedthrough interference, which is usually six orders of magnitude larger than the signal from magnetic nanoparticles. This work will showcase hardware that suppresses this interference by an order of magnitude, increasing the dynamic range of the instrument and enabling mass-limited detection at full scale range.