Verification of the LEM IV for the biological based treatment planning

The promising clinical results of the ion therapy pilot project at GSI have led to an increased interest in carbon therapy with active beam delivery [1]. Carbon ions have an increased biological effectiveness compared to photons. To predict the relative biological effectiveness (RBE) of particles in the irradiated volume the Local Effect Model (LEM I) was developed and used successfully in the pilot project [2]. A better understanding of the biological mechanisms is expected to further improve the treatment planning for carbon ions. Thus the main goal of this work was to benchmark the current version LEM IV [3] against LEM I under treatment-like conditions with idealized geometries as a first step on the way to clinical application.