Berlin 2008 – scientific programme
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ST: Fachverband Strahlen- und Medizinphysik
ST 6: Heavy Ion Therapy and Related Basic Research II
ST 6.3: Talk
Tuesday, February 26, 2008, 12:00–12:15, H 2033
Precision measurements of Bragg curves of light-ion beams in water — •Peter Steidl1, Dieter Schardt1, Uli Weber1,2, Gheorghe Iancu1, and Michael Krämer1 — 1Gesellschaft für Schwerionenforschung, Planckstr. 1, D-64291 Darmstadt, Germany — 2Rhön-Klinikum AG, Baldingerstraße, D-35043 Marburg, Germany
Depth-dose distributions in water (Bragg curves) are of key importance for validation of the physical models used for treatment planning in tumor therapy with high-energy light-ion beams. A new series of precision measurements of pristine (unmodified) Bragg curves was carried out for protons, 3He, 7Li, 12C and 16O beams at energies from 100 to 400 MeV/u delivered by the heavy-ion synchrotron SIS18 at GSI Darmstadt. The relative ionization was measured as a function of water depth using two parallel-plate ionization chambers placed upstream (for normalization) and downstream of a computer-controlled water absorber of variable thickness. The experimental Bragg curves are compared to calculations performed with the treatment planning code TRiP [1, 2]. The stopping power calculations used in TRiP are based on the code by Salamon [3]. Slight modifications were applied in order to improve the agreement with the measured absolute positions and widths of the Bragg peaks for 12C therapy beams which are used for patient treatments at GSI.
[1] M. Krämer et al., Phys Med Biol. 45(11):3299-3317 (2000)
[2] M. Krämer et al., Phys Med Biol. 45(11):3319-3330 (2000)
[3] M.H. Salamon, LBL Report 10446 (1980)