MPI head scanner
Philips Medical Systems, Hamburg
A dedicated test setup has been developed for testing and verification of Magnetic Particle Imaging (MPI).
With acknowledgement in scientific journal Nature.
This MPI setup consists of a large ferromagnetic yoke with 2 coils, creating a high gradient magnetic field (>0.21T/m) with a single field free point (<1mT) that can be moved over the scan line. By moving the yoke by an X,ϴ stage the field free point FFP can be positioned throughout the complete head volume.
At Philips Medical Systems in Hamburg MPI technology was invented to be used for medical diagnosis. This way of imaging has the potential to monitor bleedings and anomalies in the head without having to use large MRI scanners. It uses small injected magnetic particles (SPIONS) in the blood veins that can be monitored by magnetization. More on MPI technology see this video.
Philips has realized in Hamburg a room-size MPI scanner in which the FFP was moved throughout its volume by electromagnetics. On this particular setup and a lot of research and publications are done showing the potential of this technique.
To show the potential of a small size MPI system MI-Partners has developed a head size scanner with a single electromagnetic axis, combined with two mechanical axes. Having best of both worlds makes it possible to realize a low cost and low power scanner within a limited volume. This head size scanner is able to make reproducible scans within 0.1mm.
A video of the inside of the moving scanner can be found here: video
Challenges
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Highly confidential project (at the time of the project)
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Creating a magnetic field with a movable field free point (<1mT) in a relative large volume (175x180x200mm)
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Minimal building volume to place the scanner at the head-end of the patient’s bed
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Realizing large size coils with high power requirements to create the magnetic field
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Dealing with RF noise
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Low cost solution
Key Competences
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System architecture
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Magnetic modelling and verification measurements
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High power applications
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Project management
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Thermal management
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Dynamics & control
Results
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Reproducibility of the scanning motion <0.1mm
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Magnetic gradient >0.21 T/m within 2% of the modelled field
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RF Shielded system by RF cover
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Standalone GUI (based on Matlab) for controlling system and run user defined setpoints
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Electromagnetic power during scanning: 530W with margin to 1kW
Cooperation
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Magnetic Innovations: Realizing the yoke with coils
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VHE: Realization of E-cabinet/hardware
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Philips Medical Systems: Define specifications, introduction to MPI and FFP’s, developing the monitoring coil