163 research outputs found
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
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