Towards accurate modeling of the multidimensional magnetic particle imaging physics

The image reconstruction problem of the tomographic imaging technique magnetic particle imaging (MPI) requires the solution of a linear inverse problem. One prerequisite for this task is that the imaging operator that describes the mapping between the tomographic image and the measured signal is accurately known. For 2D and 3D excitation patterns, it is common to measure the system matrix in a calibration procedure, that is both, very time consuming and adds noise to the operator. The need for measuring the system matrix is due to the lack of an accurate model that is capable of describing the nanoparticles’ magnetization behavior in the MPI setup. Within this work we exploit a physical model that is based on Néel rotation for large particle ensembles and we find model parameters that describe measured 2D MPI data with much higher precision than state of the art MPI models. With phantom experiments we show that the simulated system matrix can be used for image reconstruction and reduces artifacts due to model-mismatch considerably.TK acknowledges funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—project number 281474342/GRK2224/1 'Pi3: Parameter Identification—Analysis, Algorithms, Applications' and support by the project 'MPI2' funded by the Federal Ministry of Education and Research (BMBF, project no. 05M16LBA). TK acknowledges the financial support by the German Research Foundation (DFG, grant number KN 1108/2-1) and the Federal Ministry of Education and Research (BMBF, grant number 05M16GKA and 13XP5060B). The publication is also funded by the German Research Foundation (DFG, project no. 392323616) and the Hamburg University of Technology (TUHH) in the funding programme Open Access Publishing