Magnetic Particle Imaging (MPI) is a novel tomographic method for determining the distribution of magnetic material in three dimensions. Similar to Magnetic Particle Spectroscopy (MPS), MPI is based on the nonlinear magnetization response of magnetic iron oxide nanoparticles (MNP) to dynamic magnetic fields. Additional strong magnetic field gradients are used to encode the field of view (FOV) by selectively generating higher harmonics near the encoding scheme. The encoding scheme can have different shapes, such as field-free point (FFP) or field-free line (FFL), which can be moved through the FOV in a variety of ways (trajectories) [1,2,3].
Similar to PET or SPECT, MPI is a tracer-based method, which comes with a lot advantages, such as high spatial resolution [4], high sensitivity [5] and high temporal resolution [6]. These features build a promising new technology for different fields, such as material science, biology, chemistry, and medicine. Especially the latter field shows some interesting developments in the last decade, e.g., MPI as a promising tool for future intervention, such as PTA or stenting [7-12], but also novel scanner designs for human-sized applications [13-17]. Based on one novel scanner design, the pdMPI scanner is based on the traveling wave (TW) approach, which uses a dynamic linear gradient array for the generation of the strong magnetic field gradient required for the spatial encoding [18, 19]. With this TWMPI technique, several unique features, such as real parallel MPI [20], superspeed MPI [21], zoom-MPI [22], or hybrid imaging with CT [15, 23] or MRI [24, 25] are connected. This provides new possibilities and new applications for MPI. A further development of the encoding scheme allows for the first time a fully electrical controlled 3D movement of an FFL [26] in combination with a small and lightweight hardware design [15].
The pdMPI device
Based on the TW-FFL technology, the pdMPI device provides the first benchtop 3D MPI scanner for research and education and gives an easy entry into the interesting field of MPI. The pdMPI scanner is a highly flexible system, which comes with a fully 3D simulation framework [27], which not only allows a full emulation of the scanner but also image reconstruction and visualization (2d & 3D) in real-time [28, 29]. With the openMatlab interface, the pdMPI scanner can be easily adapted and integrated into established processes in industry, research, and education. In the following, only few examples of FFL trajectories covering the data within the FOV of the scanner are shown. Until now, 10 different standard sequences are implemented but with the arbitrary adjustable frequencies, the pdMPI scanner can be set up for your application.
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References
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