  In Magnetic Particle Imaging (MPI), the distribution of magnetic
nanoparticles (MNPs) is imaged by moving a field free point (FFP) in space. All
MNPs in close vicinity of the FFP contribute to the signal induced on the
receive coil. The relaxation behavior of these MNPs are subject to a DC field
due to the selection field (SF). In this work, we investigate the effects of
the DC field on the relaxation behavior of the MNPs, with the goal of
understanding the differences between the measured relaxations in Magnetic
Particle Spectrometer (MPS) setups vs. MPI scanners.
