Tracers are widely used in various clinically available diagnostic and therapy applications. Fraunhofer IMTE focuses on tracer material based on superparamagnetic iron-oxide nanoparticles (SPIONs) which have highly biocompatible properties and are thus very promising candidates for biomedical applications - tracers are the most integral part of Magnetic Particle Imaging (MPI). When functionalized, tracers can be useful in both diagnostic as well as therapeutic applications, such as hyperthermia, cell labelling or drug delivery. They can also be used for construction of medical catheters and micro-machines that allow visualization, and even manipulation, in an MPI scanner. Fraunhofer IMTE works on the synthesis of SPIONs for various applications such as MPI, hyperthermia and cell labeling.