**4.2. Hybrid system imaging**

The superb ability of PET to detect ligand-receptor binding at the nano- to picomolar concentrations and the excellent spatial resolution of MR imaging, have stimulated efforts for the construction of hybrid PET/MRI systems. While the first prototype systems have already been completed [Herzog 2010, Pichler 2008], it will be of interest to see if corporate interest will aid establish such hybrid imaging techniques as tools of the arsenal of other diagnostic tools for clinical practice and for basic science research.
