Heidelberg 2006 – wissenschaftliches Programm
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ST: Strahlen- und Medizinphysik
ST 7: Strahlentherapie mit schnellen Ionen II
ST 7.4: Vortrag
Dienstag, 14. März 2006, 12:00–12:10, D
Calculation of Stopping Power Ratios for heavy ion dosimetry — •Oksana Geithner1, Oliver Jäkel1, Nikolai Sobolevsky2, Pedro Andreo3, and Günther Hartmann1 — 1Department of Medical Physics, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany — 2Department of Neutron Research, Institute for Nuclear Research of the Russian Academy of Sciences, 117312 Moscow, Russia — 3Division of Human Health, International Atomic Energy Agency, A-1400 Vienna, Austria
Water-to-air stopping power ratio calculations for clinical carbon ion beams of initial energies from 50 to 450 Mev/n have been performed using the Monte Carlo technique. To simulate the transport of a particle in water the computer code SHIELD-HIT v2 was used. In this most recent version of the code a number of modifications were implemented. The predecessor code SHIELD-HIT v1 was completely rewritten replacing formerly used single precision variables with double precision variables. The lower limit of the particles transport energy was reduced from 1 MeV/n down to 10 keV/n. For this purpose, the Bethe-Bloch formula was modified for lower energies. MSTAR and ICRU73 data for the stopping power values were included. The fragmentation model was verified and its parameters were adjusted. The presented version SHIELD-HIT v2 shows excellent agreement with experimental data. Calculations with the most recent version of SHIELD-HIT yielded input data for the calculation of stopping power ratios. The uncertainty of the stopping power ratio has been decreased to 0.5% compared to the uncertainty of 2% given in TRS-398.