Visualization of three-dimensional biological dose distributions

The basis for comparing 3-D treatment plans in radiotherapy are isodose curves, dose-volume histograms, and calculated tumour control and normal tissue complication probabilities. Additionally the visualization system VOXEL-MAN/RTP developed at our hospital allows to render 3-D dose distributions together with anatomical information and the volumes of interest. Regarding different types of radiation and time-dose patterns biological effects are integrated into the 3-D treatment planning and are displayed as biological doses in the same manner as the physical dose distributions. As an example the visualization of a 3-D treatment plan for photons in combination with fast neutrons will be demonstrated. Considering the differing biological effectiveness of photons and neutrons physical and biological dose distributions will be shown. Some of the principal possibilities of different display modes will be introduced.