An LSO-based scanner for in-beam PET: A feasibility study.

Over the last 3 years in-beam PET has proven its capability of quality assurance in carbon ion tumour therapy at the pilot project of cancer therapy at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany. In this paper we investigate the possibility of using LSO as the scintillation material for the next generation of in-beam PET cameras. We address the issue of background coincidences arising from the natural radioactivity of LSO. Because the true count rate measured with a BGO-based dual-head positron camera (total sensitive area of each head 21 x 42 cm²) during the cancer treatment averages at only 100 coincidences/s we studied the influence of the LSO backround on realistic in-beam PET-images.