München 2009 – wissenschaftliches Programm

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ST: Fachverband Strahlen- und Medizinphysik

ST 7: Ion Radiation Therapy 2: Target Motion Management

ST 7.4: Vortrag

Mittwoch, 11. März 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.