THE HEAVY ION GANTRY OF THE HICAT FACILITY

The Heavy Ion Cancer Therapy Project HICAT at the University Hospital of Heidelberg is under construction. One unique feature of the treatment facility is the first heavy ion gantry in the world. The gantry will allow the patient treatment with different ion species up to 430 MeV/u and full geometrical flexibility. This functionality has to be maintained for up to 300 000 rotations over the envisaged life cycle of 15 years. The order for the delivery of the supporting structure as well as the integration of the main components was given to MAN Technologie. GSI had taken the responsibility to coordinate all component suppliers and to commission the system until reliable beam conditions are reached. This paper reports on challenging construction items like the interface to the building, the position stability and the patient environment. The construction of the dedicated cancer therapy facility in Heidelberg has started [1]. The key parameters of the facility will be the following: • treatment with low and high LET-ions • relatively fast change of ion species • 3 treatment areas for up to 1000 patients per year • integration of an isocentric gantry • main ion-species: p, He, C, O • ion-range in water: 20 -300 mm • ion-energy: 50 -430 MeV/u • extraction-time: 1 – 10 s • beam-diameter: 4 – 10 mm FWHM • ions/spill: 1*10 to 4* 10 Figure 1: Layout of the first underground floor housing the accelerator complex Figure 1 shows the layout of the first underground floor of this facility with the accelerator sections and the treatment places. The accelerator chain consists of an injector linac, accelerating the ions to an energy of up to 7 MeV/u, followed by a compact synchrotron with a circumference of about 65 m. The beam is distributed by the high energy beam transport line HEBT to the four beam stations. Station one and two are fixed horizontal beam stations for patient treatment. In station three the beam is guided along an isocentric gantry allowing irradiation from all directions. The fixed beam station number four will be used for quality assurance, development and research activities. All places will be equipped with rasterscan treatment equipment for a full 3D volume conformal irradiation. entrance channel of the beam into the patient a gantry will be built which will be able to transport protons and light ions up to oxygen with energies corresponding to a penetration depth in tissue between 20 and 300 mm. INTRODUCTION THE HEAVY ION GANTRY In order to have full geometrical flexibility of the Figure 2: Overview of the isocentric ion gantry Proceedings of EPAC 2004, Lucerne, Switzerland