Optimization of Circular Current Distributions for Magnetic Field Generation in MPI: A Comparison of the Selection Field Coil and the Drive Field Coil Geometry

Magnetic Particle Imaging in general applies two different types of magnetic field geometries in order to obtain information about the spatial distribution of magnetic nanoparticles. First, a static gradient field called selection field is used for spatial encoding. It either provides a field free point or a field free line. Second, additional uniform drive fields are superimposed to steer the field free region through the field of view. Most efficiently, the latter fields are orientated perpendicularly to each other. For field generation, current carrying coils are used, while the static field generation may be supported by strong permanent magnets. In this contribution, discs carrying circular current distributions are investigated for generating both types of field geometries. These distributions are optimized with respect to the achieved field quality as well as to the total power loss.