München 2009 – scientific programme
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ST: Fachverband Strahlen- und Medizinphysik
ST 7: Ion Radiation Therapy 2: Target Motion Management
ST 7.4: Talk
Wednesday, March 11, 2009, 16:45–17:00, A021
Ion-optically driven depth compensation for ion beam tracking — •Naved Chaudhri1, Nami Saito1, Christoph Bert1, Bernhard Franczak1, Marco Durante1, Eike Rietzel2, and Dieter Schardt1 — 1GSI, Abt. Biophysik, Darmstadt — 2Siemens Healthcare, Particle Therapy, Erlangen
The beam delivery system for scanned carbon ion beam radiotherapy at GSI has been extended in research mode to irradiate moving targets. For beam tracking, the ion beam is adapted laterally as well as in range corresponding to the target's three dimensional (3D) motion. A beam tracking system with a motorized double wedge system for fast and accurate range adaptation has been developed.
In addition to the current range adaptation system a much faster method for online energy modulation is being investigated where a fine focused ion beam is dynamically positioned, controlled by fast dipole magnets, on a small static wedge shaped absorber within the beam line.
Experiments were performed at the therapy beam line to study the beam shift from central axis by the first dipole magnet up to the maximum limit where the beam can be deflected back to central axis by the second dipole magnet. Beam profiles were measured at different locations of the beam delivery system. The particle transmission was measured as well at the target position. Experiments were supported by Monte Carlo simulations for energy variation studies and for assessing the influence on beam profiles using MOCADI code.