This work comprises a multiparametric analysis of particle-matrix interactions using magnetic particle spectroscopy (MPS) and the corresponding imaging modality magnetic particle imaging (MPI). To investigate particle-matrix interactions, the dynamic magnetization response of magnetic nanoparticles to externally applied alternating magnetic fields is evaluated. Due to the nonlinear magnetization characteristics of magnetic nanoparticles, the higher harmonics of the magnetization resulting from the periodic excitation in particular serve as source of information. The measurements presented were realized with a temperature-controlled MPS setup implemented as part of this work. For multiparametric investigations, measurement parameters such as the magnetic field strength of the externally applied field, the excitation frequency, the sample temperature, the dynamic viscosity of the medium surrounding the particles or particle systems and related properties were varied. Based on the results, conclusions are drawn about physical relationships and the quantifiability of measurement results and their transferability to the MPI imaging technique are discussed. It is shown that particle-matrix interactions in MPS can be resolved in the millisecond range. Temperature-dependent measurement results are traced back to the dominant relaxation mechanism of the used particle system. With the help of Fokker-Planck simulations, the structure of multicore particles is clarified from a viscosity series based on CoFe2O4 particles. Furthermore, the influence of the dynamic viscosity on the measurement data is discussed. Magnetization curves reconstructed from the measurement data are used to analyze thermal interactions with the carrier medium. Furthermore, the spectral decomposition of the magnetization harmonics is introduced and applied to derive temperature and viscosity dependent mapping functions. Due to the degree of similarity of the measurement principles, the findings from experimental MPS data can be transferred to the MPI imaging method in order to assess and validate the quantifiability of the method. Dilution series of particle suspensions serve to characterize both the MPS setup and the institute’s custom-built dual-frequency MPI scanner. Finally, realized 2D and 3D MPI measurement results are shown and dual-frequency mobility MPI data of different viscosity levels are presented.weiterlesen