  We propose a multi-scale approach to understanding physics related to the
ion/proton-beam cancer therapy and calculation of the probability of the DNA
damage as a result of irradiation of patients with energetic (up to 430 MeV/u)
ions. This approach is inclusive with respect to different scales starting from
the long scale defined by the ion stopping followed by a smaller scale defined
by secondary electrons and radicals 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 the DNA and suggest a way
of further elaboration of such calculations.
