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Abstract

For cancer treatment, particle therapy is becoming increasingly available, featuring precise tumour targeting and favourable depth dose distributions. However, the usage of ionised particles for irradiation is accompanied by a variable and multi-dimensional biological effect. Furthermore, particle therapy is susceptible to range and beam delivery uncertainties. Therefore, new methods and techniques that analyse and mitigate these effects are presented here. To independently verify treatment plans and provide additional clinical insights on relative biological effectiveness (RBE) the FRoG (Fast dose Recalculation on GPU) analytical dose calculation engine has been adapted to a third-party treatment facility and benchmarked. Analyses of a biophysical dose-model that will be used for the first helium-ion therapy with active scanning was carried out, yielding considerable dose-differences for clinically relevant biological assumptions in a biological-sensitivity study. Furthermore, the dose uncertainty of applying a mixed radiation field particle-spectra was quantified, revealing non-negligible but clinically acceptable dose differences. A novel method that combines multiple ion-species in the same treatment field to yield constant RBE, potentially reducing the RBE uncertainty of light ions was developed and experimentally verified in homogeneous and heterogeneous conditions. The investigations presented here contribute to the uncertainty evaluation and reduction of future particle treatments.