  By representing damage induction by ionizing particles and its repair by the
cell, the probabilistic two-stage model provides a detailed description of the
main processes involved in cell killing by radiation. To link this model with
issues of interest in hadron radiotherapy, a simple physical model is used.
Energy loss, its straggling, and the attenuation of the primary particle
fluence are represented in a simplified way, based on semi-phenomenological
formulas and energy-loss tables. An effective version of the radiobiological
model is joined with the simple physical model to estimate cell survival along
ions' penetration depth. The predicted survival ratios for CHO cells irradiated
by carbon ions are presented, showing very good agreement with experimental
data.
