  We propose a multi-scale approach to understand the physics related to
ion-beam cancer therapy. It allows the calculation of the probability of DNA
damage as a result of irradiation of tissues with energetic ions, up to 430
MeV/u. This approach covers different scales, starting from the large scale,
defined by the ion stopping, followed by a smaller scale, defined by secondary
electrons and radicals, and ending with the shortest scale, defined by
interactions of secondaries with the DNA. We present calculations of the
probabilities of single and double strand breaks of DNA, suggest a way to
further expand such calculations, and also make some estimates for glial cells
exposed to radiation.
