Multi-channel and multi-resonance receiving system for magnetic particle imaging

• Applicant: Professor Dr.-Ing. Volkmar Schulz
• Subject Area: Medical Physics, Biomedical Technology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 525754375

Magnetic particle imaging (MPI) is a new tracer-based imaging technology that can determine the spatial distribution of superparamagnetic iron oxide-based nanoparticles (SPIONs) in vivo. SPIONs are single magnetic domain particles characterized by a nonlinear magnetization response to external magnetic field changes. MPI offers submillimeter spatial resolution and excellent temporal resolution at tens of volumes per second. While commercially available devices to date have been designed for preclinical and research purposes only, MPI has great potential to become a clinical tool due to its quantitative, depth-independent, non-invasive, and radiation-free nature. Further advances in sensitivity, spatial resolution, and tracer performance are needed for clinical implementation. Currently, the sensitivity and image resolution of preclinical MPI systems can be improved by using special receiving coils with separately tuned receiving electronics. The lowest reported iron detection limit of 2.8 μmol(Fe)/l was achieved with a highly sensitive gradiometric receive coil. However, this still exceeds the predicted iron detection limit of 0.1-1 μmol(Fe)/l by about an order of magnitude. In addition to hardware challenges (e.g., shielding, signal amplification, background drift) and the need for MPI-specific tracer optimization, a major reason for the observed deviation from the predicted detection limit is the systematic and stochastic noise in the measurement vector and calibration measurement. In this project proposal, we propose a cost-effective, handy, and purely passive coil insert that provides frequency-selective signal enhancement instead of using a dedicated receive coil with a separate and matched receive chain. The passive dual coil resonator is designed to fit within the bore of a preclinical MPI scanner. We hypothesize that the presented concept can be used to massively increase the sensitivity and spatial resolution of future MPI measurements via multi-resonance and multi-channel configurations. This DFG proposal aims to systematically investigate this hypothesis.

• DFG Programme: Research Grants