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Radiation and Environmental Biophysics

, Volume 40, Issue 1, pp 23–31 | Cite as

Calculation of radiation-induced DNA damage from photons and tritium beta-particles

Part I: Model formulation and basic results
  • V. V. Moiseenko
  • R. N. Hamm
  • A. J. Waker
  • W. V. Prestwich
Original Paper

Abstract 

Radiation-induced damage in nucleosomal DNA was modelled by Monte Carlo means. An atomistic representation of DNA with a first hydration shell was used. DNA single- and double-strand break (SSB and DSB) yields were calculated for 137Cs photons, x-rays and tritium beta-particles. Monte Carlo-generated electron tracks for liquid water were used to model energy deposition. Chemical evolution of a track and interactions between species and DNA following water radiolysis were modelled in an encounter-controlled manner. The effects of varying the scavenging capacity of the environment, the extent of DNA protection by histones and the setting of a threshold for direct energy depositions on DNA break yields were all systematically studied. DSB complexity was assessed in terms of DNA breaks and base damage accompanying a DSB. Model parameters were adjusted to make predictions consistent with experimental data on DSB yields and yield modification by a variety of factors including changing DNA conformation and incorporation of scavengers. An embedded model of nucleosomal DNA by histones was required to explain experimentally observed modification of DSB yield by removal of bound histones. Complex DSB, defined as DSB accompanied by an additional strand breakage, exhibited high association with base damage. It is shown that hydroxyl radical interactions with bases are a major contributor to DSB complexity. On average there were 1.15 and 2.69 OH-base interactions accompanying simple and complex DSB, respectively for 137Cs. Over 80% of complex DSB had at least one OH-base interaction associated with a DNA break.

Keywords

Energy Deposition Break Yield Base Damage Strand Breakage Water Radiolysis 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • V. V. Moiseenko
    • 1
  • R. N. Hamm
    • 2
  • A. J. Waker
    • 3
  • W. V. Prestwich
    • 4
  1. 1.Physics Department, London Regional Cancer Centre, 790 Commissioners Road East, London, Ontario, N6A 4L6, Canada e-mail: vmoiseen@phy.lrcc.on.ca Tel.: +1-519-6858300, Fax: +1-519-6858658CA
  2. 2.Oak Ridge National Laboratory, Oak Ridge, TN 37831-6123, USAUS
  3. 3.AECL, Chalk River Laboratories, Chalk River, Ontario, K0J 1J0, CanadaCA
  4. 4.Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4K1, CanadaCA

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