The investigation of different cameras for in-beam PET imaging.

In situ and in vivo treatment plan verification and beam monitoring as well as dose control during heavy-ion tumour therapy can be performed in principle by measurements of range distributions of beta(+)-emitting nuclei by means of PET techniques. For this purpose the performance of different types of positron camera as well as the results of in-beam PET experiments using beams of beta(+)-active heavy ions (15O, 17F and 19Ne with energies of 300-500 A MeV) are presented. Following the deduced performance requirements a PET scanner that is designed for clinical use in experimental heavy-ion therapy at GSI Darmstadt has been built. This limited angle tomograph consists of two large-area detector heads based on position sensitive BGO detectors and is predicted to perform the measurement of the end point of a beta(+)-emitting ion beam for the verification of a treatment plan with a precision better than 1 mm. The maximum dose applied in the patient thereby is of the magnitude of 10 mGy.

The application of PET to quality assurance of heavy-ion tumor therapy.

At the new heavy ion tumor therapy facility of the Gesellschaft für Schwerionenforschung at Darmstadt positron emission tomography (PET) has been implemented for in-beam and in-situ therapy control, i.e. during the tumor irradiation. The components necessary for this dedicated PET-imaging and their integration into the framework of therapy planning and quality assurance of heavy ion cancer treatments are presented. Results of the first application of this PET-method to patient treatments are reported.