Radiobiological basis of hadrontherapy

After a description of the rationale for the therapeutic use of charged hadrons, this paper briefly reviews the measured radiobiological properties of therapeutic hadron beams together with some relevant biophysics model aimed at their interpretation and at predicting the biological effects in mixed radiation fields. The problem of deriving a “clinical” RBE from the “biological” one is also shortly described, considering separately the proton and carbon ions cases. For the former case the simplifying assumption of RBE=1.1 (and criticisms to it) currently adopted in general by the proton therapy Centres is described, while for the latter case the main two approaches (developed in Japan and in Germany) are outlined. Finally, the importance of gaining a better knowledge in hadron radiobiology is addressed. This need is put into the perspective of the increasing number of hadrontherapy facilities in the world and in Italy in particular.