Mouse Bed Optimized for MPI

Magnetic particle imaging (MPI) is a new imaging modality, which allows for the determination of the distribution of super paramagnetic nanoparticles in vivo with excellent contrast, penetration and high temporal resolution. So far, real-time imaging in a mouse has been realized using a scanning-system with a field free point (FFP). Recently, an alternative encoding scheme has been developed promising faster scanning times and a higher sensitivity. This can be handled by extending the FFP to a field free line (FFL). Preliminary scans of phantoms showed the feasibility of the FFL in practice, based on projection x-space MPI. To ensure the safety of imaging switching from phantom to in vivo scans, a specific protocol has to be provided for scanning live animals. This paper describes the construction and testing of a mouse bed for heating as well as delivery and recovery of anesthesia gases. The mouse bed is constructed with non-magnetic materials and sized to the specific scanner. The size of the bed is limited by the diameter of the bore, and a larger bed (and bore) would be required for larger animals.

We designed a mouse bed fulfilling all mentioned requirements by engineering a specialized water warming system and a modified connection for the anesthesia system. The whole bed is moveable and rotatable in and around the longitudinal axis of the bore by jointing it to a robot. Rotation is critical for performing volumetric 3D MPI with projection reconstruction (or Radon) computerized tomography.