Selective and quantitative magnetic particle imaging of magnetically labelled cells

• Applicant: Dr.-Ing. Norbert Löwa
• Subject Area: Medical Physics, Biomedical Technology
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 455706279

The imaging method Magnetic Particle Imaging (MPI) uses magnetic nanoparticles (MNP) as signal-generating probes to record their distribution in the body quantitatively and with high temporal resolution. The MPI signal generation and consequently the image quality depends on the properties of the MNP like no other known imaging method. The magnetic properties are determined by both the particle structure and above all the colloidal environment of the MNP. With the availability of commercial MPI scanners and a wide range of MNP with proven MPI suitability, the necessary technological foundations have now been laid to demonstrate the suitability of MPI technology in the investigation of clinical research questions.Especially the visualization of inflammatory cells using MPI can provide significant added value compared to established imaging techniques. Finally, the MPI method has the potential to track cells in real time and at the same time provide information about the cell state or cell type. Before the cells can be tracked by MPI, they must be loaded with suitable MNP.In this project the suitability of the MPI technology for selective and quantitative visualization of cells will be investigated. It will be investigated whether co-localisation of different cell populations as well as different cell states is possible without sacrificing the advantages of MPI imaging such as high temporal resolution and quantifiability. Only little is known about the internalization of MNP by cells and the resulting signal changes in MPI imaging. For this reason, we will systematically analyse correlations between the MPI signal and the biological behaviour of MNP, the cellular uptake and degradation process and the physiological state of the cells. In order to subsequently provide uniform populations of MNP-loaded cells for imaging, magnetic preselection will be established. This procedure serves as the basis for an improved signal-to-noise ratio in MPI and an optimized differentiation of cell states and types. Furthermore, a magnetic preselection guarantees a reproduceable and reliable application of MNP-labelled cells. The selective and quantitative imaging of MNP-loaded monocytes will be realized by means of adapted reconstruction algorithms. Suitable phantoms and an atherosclerosis model will be used to demonstrate and evaluate the performance of a preclinical MPI scanner for selective and quantitative cell imaging.

• DFG Programme: Research Grants
• Co-Investigator: Privatdozentin Dr. Antje Ludwig