Patient irradiations at GSI

D. Schulz-Ertner, C. Thilmann, M. Wannenmacher, J. Debus Before patient irradiations started in 1997, a radiation unit was built at the heavy ion synchrotron of the GSI and major future directed technical and radiobiological innovations have been implemented. For the first time, tumor conform application of carbon beams was realized by intensity-controlled rasterscanning with pulse-to-pulse energy variation . All patients had 3D treatment planning including a biological plan optimization using the treatment planning program TRIP developed at GSI . A PET camera is used for online beam verification . Up to now, 73 patients with tumors of the skull base and the brain have been treated with carbon ions. The study mainly contained patients with chordomas (33) and low grade chondrosarcomas (16) of the skull base, adenoid cystic carcinomas (8) and malignant meningiomas (8). These tumors are known to be relatively radioresistant against conventional photon irradiation. Proton radiotherapy has been shown to improve outcome in chordomas and low grade chondrosarcomas [4] but its availability is limited. In adenoid cystic carcinomas radiation therapy with heavy particles as neutrons results in improved local control rates compared to photon irradiation but causes severe side effects . Malignant meningeomas commonly recur within the former irradiated fields even after high tumor doses. Carbon ion therapy presents a promising therapy option in the management of these tumors. Within the feasibility study, median tumor dose was 60 GyE in chordomas and chondrosarcomas. Patients with adenoid cystic carcinomas and malignant meningiomas received fractionated stereotactic photon irradiation at Heidelberg University with a median dose of 50.4 Gy and a carbon ion boost with 18 GyE (6 x 3.0 GyE) to the gross tumor. Feasibility