Physics of ion beam cancer therapy: a multi-scale approach

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.Comment: 18 pag,5 fig, submitted to PR

Ion-induced electron production in tissue-like media and DNA damage mechanisms

We propose an inclusive approach for calculating characteristics of secondary electrons produced by ions/protons in tissue-like media. This approach is based on an analysis of the projectile's interaction with the medium on the microscopic level. It allows us to obtain the energy spectrum and abundance of secondary electrons as functions of the projectile kinetic energy. The physical information obtained in this analysis is related to biological processes responsible for the irrepearable DNA damage induced by the projectile. In particular, we consider double strand breaks of DNA caused by secondary electrons and free radicals, and local heating in the ion's track. The heating may enhance the biological effectiveness of electron/free radical interactions with the DNA and may even be considered as an independent mechanism of DNA damage. Numerical estimates are performed for the case of carbon-ion beams. The obtained dose-depth curves are compared with results of the MCHIT model based on the GEANT4 toolkit.Comment: 9 pages, 7 figures, submitted to EPJD, included class files svepj.clo, svjour.cl

A multi-scale approach to the physics of ion beam cancer therapy

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.Comment: submitted to RADAM2008 proceedings. 8 pages,5 Figures, class files for AIP include