%0 Journal Article
%A Burigo, Lucas Norberto
%A Ramos-Méndez, José
%A Bangert, Mark
%A Schulte, Reinhard W
%A Faddegon, Bruce
%T Simultaneous optimization of RBE-weighted dose and nanometric ionization distributions in treatment planning with carbon ions.
%J Physics in medicine and biology
%V 64
%N 1
%@ 1361-6560
%C Bristol
%I IOP Publ.
%M DKFZ-2019-00055
%P 015015 
%D 2019
%X Inverse treatment planning in intensity modulated particle therapy (IMPT) with scanned carbon-ion beams is currently based on the optimization of RBE-weighted dose to satisfy requirements of target coverage and limited toxicity to organs-at-risk (OARs) and healthy tissues. There are many feasible IMPT plans that meet these requirements, which allows the introduction of further criteria to narrow the selection of a biologically optimal treatment plan. We propose a novel treatment planning strategy based on the simultaneous optimization of RBE-weighted dose and nanometric ionization details (ID) as a new physical characteristic of the delivered plan beyond LET. In particular, we focus on the distribution of large ionization clusters (more than 3 ionizations) to enhance the biological effect across the target volume while minimizing biological effect in normal tissues. Carbon-ion treatment plans for different patient geometries and beam configurations generated with the simultaneous optimization strategy were compared against reference plans obtained with RBE-weighted dose optimization alone. Quality indicators, inhomogeneity index and planning volume histograms of RBE-weighted dose and large ionization clusters were used to evaluate the treatment plans. We show that with simultaneous optimization, ID distributions can be optimized in carbon-ion radiotherapy without compromising the RBE-weighted dose distributions. This strategy can potentially be used to account for optimization of endpoints closely related to radiation quality to achieve better tumor control and reduce risks of complications.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:30523890
%R 10.1088/1361-6560/aaf400
%U https://inrepo02.dkfz.de/record/142252