Biochemical Engineering

Medical imaging modalities such as X-ray, Computed tomography (CT) and Magnetic resonance imaging (MRI) are of increasing importance in clinical pathways. Common to those modalities is the use of contrast agents in order to enhance image quality and thus improve diagnosis. X-ray and CT mostly require iodine-containing agents while MRI uses agents containing gadolinium, mangan or iron oxide suspensions.

Magnetic particle imaging is a recently proposed method for the visualization of the spatial distribution of iron oxide nanoparticles. The imaging principle is based on the superparamagnetic nature of Fe3O4 particles. If the particles are subjected to an oscillating magnetic field, according to Langevin’s theory of paramagnetism, a nonlinear response of the magnetization will be measured. Iron oxide particles covered with dextran and derivatives are widely used as contrast agents in MRI imaging. However, currently available particles suffer from a short sojourn time in the vessels often leading to image quality degradation. It has been conjectured that ultra small particles would lead to an improved visibility e.g. of small capillary vessels.