The increased biological effectiveness of heavy charged particle radiation: from cell culture experiments to biophysics modelling.
One of the major advantages of heavy ion tumor therapy is the increased relative biological effectiveness (RBE) of particle beams in particular at the end of their penetration depth, i.e. in the tumor volume. This increased effectiveness has to be taken into account for treatment planning. The RBE cannot be represented by a single number, but depends in a complex way on different factors like e.g. ion type and energy, depth in tissue, dose level and the tissue type. For applications of ion beams in tumour therapy, the increased RBE requires a corresponding general reduction in dose. In particular, due to the variation of RBE with depth, the shape of the depth dose profile has to be adapted accordingly.
In the first part, the lecture will summarize the essential radiobiological aspects, which have been extensively studied within the framework of heavy ion tumour therapy projects. The second part then will focus on the theoretical modelling of the radiobiological effects of charged particle beams, which is required for the implementation of a biologically optimized treatment planning.