In-beam Positron Emission Tomography for Ion Therapy Monitoring

Due to the special characteristics of ion beams and delicate treatment situations, i.e. in close vicinity to organs at risk, a three-dimensional, in-vivo and in-situ monitoring of the dose delivery is highly desirable. At present, in-beam PET is the only method meeting these requirements. An in-beam PET system has been implemented for clinical application at the carbon ion therapy facility of the Gesellschaft für Schwerionenforschung (GSI) Darmstadt. So far, more than 400 patients have been monitored with this system. It could be demonstrated that this PET technique is capable of assessing relevant parameters for quality assurance of carbon ion therapy, measuring the particle range in tissue, the position of the irradiated volume with respect to anatomical landmarks, and estimating local deviations between the planned and applied dose. In-beam PET has become a tool providing valuable clinical feedback. The implementation of the in-beam PET system at the medical beamline at GSI will be described. Clinical results will be shown with examples. Furthermore, the application of in-beam PET for protons, 3-He, 7-Li and 16-O shows promising results and will be presented.