Spectroscopy for Magentic Particle Imaging

Magnetic Particle Imaging is based on the non-linear magnetization behavior of superparamagnetic iron oxide nanoparticles (SPIOs). Such SPIOs, as Resovist (Schering AG), are very established as contrast agent for Magnetic Resonance Imaging (MRI). However, for MPI the behavior of SPIOs is not fully evaluated. Therefore, the institute works on the development of magnetic particle spectrometers (MPS) to evaluate the performance of various commercially available MRI contrast agents as well as specifically synthesized MPI tracers. MPS can be interpreted as a zero-dimensional MPI scanner. It consists of one drive field coil and one receive coil. In contrast to a multi-dimensional MPI scanner, no spatial encoding is applied. Thus, all particles are subjected to the same oscillation field. The change in particle magnetization is measured by the receive coil.

The magnetization behavior of SPIOs can be modeled by the Langevin theory of paramagnetism, which can be used for simulations. Simulated and measured spectra of Resovist at different field strengths are shown in figure 1. It can be seen that simulation and measurement results are highly correlated.

A part of the MPS project is driven further as spin-off activity, the Fork Labs. It aims on the commercialization of the MPS technology and is funded by the German Federal Ministry of Economics and Technology.