A physical phantom modeling extended magnetic nanoparticle distributions in biological systems

Abstract

The detection and quantification of the spatial distribution of magnetic nanoparticles in biological tissue is an important task in the control of their diagnostic and therapeutic applications. Prominent medical applications of magnetic nanoparticles are magnetic drug targeting, magnetic hyperthermia or magnetic resonance contrast agents. The detection procedures require sensitive measurement hardware in combination with novel mathematical methods to reconstruct the magnetic nanoparticle distribution in extended body organs from non-invasively measured magnetic field patterns. Before application in biological tissues, the reconstruction procedures have to be tested and validated on samples with known magnetization and magnetic field structure. Presented is a simple but straightforward coil phantom model resembling a defined and controllable magnetic nanoparticle distribution. We demonstrate the capability of our phantom reconstructing distribution parameters from measured magnetic field patterns generated by the coils. To this end we performed minimum norm estimates with either multiple magnetic dipoles or a multipole expansion of the coil geometry as forward models. © 2009 Springer-Verlag.