System matrices for field of view patches in magnetic particle imaging

In Magnetic Particle Imaging the spatial distribution of superparamagnetic iron-oxide nanoparticles is determined using oscillating magnetic fields. The change of particle magnetization is recorded with receive coils. Spatial encoding is achieved with a superimposed gradient field featuring a field-free point. Particles not located in the vicinity of this point are in saturation and therefore do not induce a signal in the coils. Image reconstruction based on a system matrix is accurate, but time consuming. Recently, a method was introduced that images several small patches instead of one large field of view. This contribution applies this approach and additionally suggests to reusing the system matrix of one patch for the reconstruction of all patches. We will motivate this idea with symmetry characteristics of the magnetic fields applied in Magnetic Particle Imaging and perform a simulation study on homogeneous as well as inhomogeneous fields to show the potential of the approach.