Requirements on the instrumentation of a prompt gamma measuring device

The only clinically applied in-vivo dosimetry method for ion beams is Positron Emission Tomography (PET). Between 1997 and 2008, the in-beam PET method was used at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany, for monitoring the dose delivered by ¹²C beams. Due to inherent limitations of this method, a direct quantification of the delivered dose is not feasible. Therefore, another approach currently under investigation monitors the dose via the detection of prompt gamma rays. It has been shown by several groups that monitoring of an ion beam treatment via photon measurement is possible. Because of the high energy of the produced gamma rays and the required spatial resolution, the favored technical solution is a Compton camera system. The project is aimed to design and construct such a camera, and evaluate if it could lead to clinical applications.