Magnetic Particle Imaging in Vascular Imaging, Immunotherapy, Cell Tracking, and Noninvasive Diagnosis

Figure 3

Tracers of MPI obey (a) Langevin physics (blue line). At UC Berkeley, we have discovered that SPIO particles interact to create a new form of magnetic behavior which provides a step-like change in response to a magnetic field (red line). We coined this new type of particle as superferromagnetic iron oxide nanoparticles (SFMIO). (b) The step response-like behavior of SFMIO particles to the applied field provides high resolution and higher signal compared to VivoTrax™ as shown by the point-spread function (PSF) of the particles. (Reproduced with permission from Tay et al., Small Methods, 2021 [40]) (c) MPI images of VivoTrax™ filled in capillary tubes to create a pointillism phantom acquired using a 6.3 T/m field-free line MPI scanner versus (d) SFMIO particles. SFMIOs have been shown to improve the resolution of MPI to 100 microns, a 10-fold improvement compared to commercial nanoparticles [40, 42, 43].

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