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

Figure 2

Unlike the small molecule metal chelators used in nuclear medicine which are typical 1-2 nm in size, MPI uses colloids of (a–c) iron oxide nanoparticles (SPIO) with core sizes of 4–28 nm [27]. For this reason, many MPI applications studied thus far bears a close resemblance to nuclear medicine studies using (adapted with permission from Yu et al., ACS Nano, 2017. Copyright (2017) American Chemical Society, Chandrasekharan et al., Theranostics, 2020 [39]; Tay et al., Small Methods, 2021 [40]) (d) ^99mTc-Sulfur colloids [41], but with no radiation nor any radioactive decay. Signals from the MPI tracer persist until the SPIO particles are enzymatically hydrolyzed and cleared (Reproduced with permission from Michenfelder MM et al., J Nucl Med Technol, 2014).

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