%0 Journal Article
%A Titt, Uwe
%A Sell, Martin
%A Unkelbach, Jan
%A Bangert, Mark
%A Mirkovic, Dragan
%A Oelfke, Uwe
%A Mohan, Radhe
%T Degradation of proton depth dose distributions attributable to microstructures in lung-equivalent material.
%J Medical physics
%V 42
%N 11
%@ 0094-2405
%C New York, NY
%M DKFZ-2017-03668
%P 6425 - 6432
%D 2015
%X The purpose of the work reported here was to investigate the influence of sub-millimeter size heterogeneities on the degradation of the distal edges of proton beams and to validate Monte Carlo (MC) methods' ability to correctly predict such degradation.A custom-designed high-resolution plastic phantom approximating highly heterogeneous, lung-like structures was employed in measurements and in Monte Carlo simulations to evaluate the degradation of proton Bragg curves penetrating heterogeneous media.Significant differences in distal falloff widths and in peak dose values were observed in the measured and the Monte Carlo simulated curves compared to pristine proton Bragg curves. Furthermore, differences between simulations of beams penetrating CT images of the phantom did not agree well with the corresponding experimental differences. The distal falloff widths in CT image-based geometries were underestimated by up to 0.2 cm in water (corresponding to 0.8-1.4 cm in lung tissue), and the peak dose values of pristine proton beams were overestimated by as much as ˜35
%K Protons (NLM Chemicals)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:26520732
%2 pmc:PMC4608968
%R 10.1118/1.4932625
%U https://inrepo02.dkfz.de/record/127645