Development of new scintillators for medical applications

For a long time the discovery of new scintillators has been more serendipitous than driven by a deep understanding of the mechanisms at the origin of the scintillation process. This situation has dramatically changed since the 1990's with an increased demand for scintillators of better performance for large particle physics experiments as well as for medical imaging. It is now possible to design a scintillator for a specific purpose. The bandgap can be adjusted, the traps energy levels and their concentration can be finely tuned and their influence can be damped or on the contrary enhanced by specific doping for an optimization of the performance of the scintillator. Several examples are given in this paper of such crystal engineering attempts to improve the performance of crystal scintillators used in medical imaging devices. An attention is also given to spectacular progress in crystal production technologies, which open new perspectives for large scale and cost effective crystal production with consistent quality.