Page 219 - Computational Modeling in Biomedical Engineering and Medical Physics

208 Computational Modeling in Biomedical Engineering and Medical Physics

Figure 6.30 Concentration of MNPs at the end of the diffusion process through the target tissue
3
(color map and level contours, c max 5 0.33 mg/cm ) and mass flux of MNPs (thick red lines). (A) In
the presence of the magnetic field (diffusion under the action of the magnetic forces). (B) Without
magnetic field (free mass diffusion). MNP, magnetic nanoparticles.

The progress of the MNPs to the target ROI is accompanied by the change in the
susceptivity of the membrane and tissue. Consequently the magnetic field distribution
is changing, hence the magnetic forces. It is also important to notice that gradient of
the magnetic energy density, which is in fact a motive force, is not everywhere
directed towards the magnet.