  Magnetic Particle Imaging (MPI) has been successfully used to visualize the
distribution of superparamagnetic nanoparticles within 3D volumes with high
sensitivity in real time. Since the magnetic field topology of MPI scanners is
well suited for applying magnetic forces on particles and micron-sized
ferromagnetic devices, MPI has been recently used to navigate micron-sized
particles and micron-sized swimmers. In this work, we analyze the
magnetophoretic mobility and the imaging performance of two different particle
types for Magnetic Particle Imaging/Navigation (MPIN). MPIN constantly switches
between imaging and magnetic modes, enabling quasi-simultaneous navigation and
imaging of particles. We determine the limiting flow velocity to be 8.18 mL/s
using a flow bifurcation experiment, that allows all particles to flow only
through one branch of the bifurcation. Furthermore, we have succeeded in
navigating the particles through the branch of a bifurcation phantom narrowed
by either 60% or 100% stenosis, while imaging their accumulation on the
stenosis. The particles in combination with therapeutic substances have a high
potential for targeted drug delivery and could help to reduce the dose and
improve the efficacy of the drug, e.g. for specific tumor therapy and ischemic
stroke therapy.
