In vivo imaging with an upgraded single-sided magnetic particle imaging scanner

Magnetic particle imaging (MPI) is a tracer-based biomedical imaging modality where the tracer is a superparamagnetic iron oxide (SPIO) nanoparticle. We have developed a single-sided MPI scanner that has the advantage of housing all hardware on one side, allowing for greater flexibility in accessing the scanning area. Recently, the scanner was upgraded by adding a novel surface-volume excitation coil, which provides greater field uniformity, strength, and thus sensitivity. Also, enhancements were made in selection coils and electronics, which altogether made it possible to image in a larger field of view (FOV) with higher spatial resolution. This study focuses on the first in vivo imaging of animals using a single-sided MPI scanner. Two Scarb1 ApoE mice were injected intravenously with a commercially available SPION Synomag-D 70 nm, and imaging was done after a hour of wait time for each mouse. In MPI images, the nanoparticle concentrations were clearly identifiable at the expected body regions of mice, with variation in concentrations. This success in small animal imaging is a milestone for the MPI modality to keep striving to translate it into larger animal scale, with an ultimate target of human scale.