Signal Separation in Magnetic Particle Imaging

Magnetic particle imaging (MPI) applies oscillating magnetic fields to measure the distribution of magnetic nanoparticles in-vivo. Using receive coils, the change of the particle magnetization can be detected. However, the signal induced by the nanoparticles is superimposed by the signal induced by the sinusoidal excitation field, which directly couples into the receive coils. As the latter is several magnitudes higher, the separation of the particle signal from the excitation signal is a challenging task. One way to remove the excitation signal from the induced voltage in the receive coil is to suppress the excitation signal at its base frequency by means of a band-stop filter. An alternative is to recover the particle signal by compensating the excitation signal in the receive chain, which allows recovering the particle signal at its full bandwidth. In this work, it is proposed to combine both methods which allows increasing the dynamic range of the recorded signal while still recovering the fundamental frequency.