Sensitivity of helium beam-modulator design to uncertainties in biological data

Rapid calculation of biological effects in ion radiotherapy

We describe a method for fast calculation of biological effects after ion irradiation. It is an alternative derivative of the established local effect model (LEM) and has been integrated into GSI's TRiP98 treatment planning system. We show that deviations from our classic approach for treatment planning are less than 5% for therapeutical doses, but calculational speed can be improved by one to two orders of magnitude. This will allow sophisticated methods of treatment planning for ion irradiation, taking biological effects fully into account.

Treatment planning for heavy-ion radiotherapy: calculation and optimization of biologically effective dose

We describe a novel approach to treatment planning for heavy-ion radiotherapy based on the local effect model (LEM) which allows us to calculate the biologically effective dose not only for the target region but also for the entire irradiation volume. LEM is ideally suited for use as an integral part of treatment planning code systems for active dose shaping devices like the GSI raster scan system. Thus it has been incorporated into our standard treatment planning system for ion therapy (TRiP). Single intensity modulated fields can be optimized with respect to a homogeneous biologically effective dose. The relative biological effectiveness (RBE) is calculated separately for each voxel of the patient CT. Our radiobiologically oriented code system has been used since 1995 for the planning of irradiation experiments with cell cultures and animals such as rats and minipigs. It has been in regular and successful use for patient treatment planning since 1997.