Regensburg 2010 – wissenschaftliches Programm
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ST: Fachverband Strahlen- und Medizinphysik
ST 11: High-LET Radiation Therapy 1
ST 11.3: Vortrag
Donnerstag, 25. März 2010, 10:10–10:30, H41
Optimisation of the ion optical range adaptation method for tracking of moving tumours with scanned ion beams — •Anna Constantinescu1,2, Nami Saito1, Naved Chaudhri1, Marco Durante1,2, and Christoph Bert1 — 1GSI, Darmstadt, Deutschland — 2Technische Universität Darmstadt, Deutschland
Currently an ion optical solution for beam tracking of moving targets with scanned ion beams is being investigated at GSI for the treatment of moving tumours, such as lung cancer. Beam tracking compensates target motion by adapting the lateral beam position as well as the beam range according to the motion parameters. Tracking of the lateral position is achieved via scanning magnets. For range adaptation the proposed ion optical solution uses an energy degrader with variable thickness inserted into the therapy beam line downstream of the synchrotron. By deflecting the particle beam via dipole magnets to different positions on the degrader, the range of the Bragg peak can be adjusted in real-time. Hence density changes due to organ motion can be compensated for each target spot during beam scanning.
In order to reach a beam quality suitable for therapy with this method, systematic studies on the ion optical parameters have to be carried out. Different degrader designs (ramp or discrete step shaped), different materials (e.g. PMMA, graphite), as well as optimised degrader positions have been examined. The results of simulated beam profiles will be presented.