Simulational validation of color magnetic particle imaging (cMPI).

Exploiting the field response of magnetic tracers, magnetic particle imaging (MPI) allows direct, local quantification of the tracer concentration in bulk structures. Here, we investigated the use of characteristic field response functions to spatially resolve the absolute concentration of multiple nanoparticle species by simulation. In particular, using various drive and selection field strengths, we devised color MPI (i.e. cMPI) to quantify and disentangle MPI signals from the mixed Langevin particles of variable concentration and magnetic susceptibility. Specifically, the drive field strength was optimized to distinguish individual field responses from differently sized iron-oxide nanoparticles without compromising the image quality. The proposed cMPI technique is implementable on an existing MPI setup and can be used to quantify biophysical parameters including size-dependent bio-distribution and altered magnetic property of particles. The current study result, simultaneous visualization of the multiple magnetic tracers, theoretically validates the potential feasibility of cMPI as a versatile biosensor and contrast imaging method.