Volker Christian Behr1, Thomas Kampf1,
Jan-Philip Gehrcke1, Martin Andreas Rckert1,2, Patrick
Vogel1,2, Walter H. Kullmann2, Peter Michael Jakob1,3
1Experimental Physics 5, University
of Wrzburg, Wrzburg, Germany; 2Medical Engineering, University
of Applied Sciences Wrzburg-Schweinfurt, Schweinfurt, Germany; 3Magnetic
Resonance Bavaria e.V., Wrzburg, Germany
In magnetic particle imaging (MPI), Langevins single particle model (SPM) yields a linear relation between magnetic particle concentration c and higher harmonic amplitudes. In reality, the MPI signal is, due to dipolar interactions, non-linearly related to c. Using a second order modified mean field theory for a more adequate modeling of the system simulations were performed to examine deviations from the prediction by the SPM. The results of these simulations are validated by experiments on the concentration dependence. Ignoring the impact of higher concentrations on the MPI signal may lead to severe errors in the interpretation of measured data.