Correction of linear system drifts in magnetic particle imaging.

Magnetic particle imaging (MPI) is a tracer-based imaging technique that can be used for imaging vessels and organ perfusion with high temporal resolution. Background signals are a major source for image artifacts and in turn restrict the sensitivity of the method in practice. While static background signals can be removed from the measured signal by taking a dedicated background scan and performing subtraction, this simple procedure is not applicable in case of non-stationary background signals that occur in practice due to e.g. temperature drifts in the electromagnetic coils of the MPI scanner. Within this work we will investigate a dynamic background subtraction method that is based on two background measurements taken before and after the object measurement. Using first-order interpolation it is possible to remove linear background changes and in turn significantly suppress artifacts. The method is evaluated using static and dynamic phantom measurements and it is shown that dynamic background subtraction is capable of reducing the artifact level approximately by a factor of four.