[ RadSafe ] Article: Simulation of DNA damage

[John Jacobus]

I have not had a chance to read this, but I thought I
would pass along the abstract.  From "Physics in
Medicine and Biology," Volume 51, 7 April 2006
http://www.iop.org/EJ/toc/-alert=1462/0031-9155/51/7

Fast Monte Carlo simulation of DNA damage formed by
electrons and light ions
    V A Semenenko and R D Stewart
    2006 Phys. Med. Biol. 51 1693-1706
    Abstract: 
http://www.iop.org/EJ/abstract/-alert=1462/0031-9155/51/7/004
    Full text PDF:
http://www.iop.org/EJ/article/-alert=1462/0031-9155/51/7/004/pmb6_7_004.pdf

    The passage of ionizing radiation through living
organisms initiates physical and chemical processes
that create clusters of damaged nucleotides within one
or two turns of the DNA. These clusters are widely
considered an important initiating event for the
induction of other biological endpoints, including
cell killing and neoplastic transformation. Monte
Carlo simulations of the DNA damage formation process
are a useful adjunct to experiments because they
provide additional information about the spatial    
configuration of damage within a cluster. In this 
paper, the fast Monte Carlo damage simulation (MCDS)
algorithm is re-parameterized so that yields of
double-strand breaks, single-strand breaks and sites
of multiple base damage can be simulated for
electrons, protons and α particles with kinetic
energies on the order of GeV. The MCDS algorithm
provides a useful, quasi-phenomenological scheme to
interpolate damage yields from computationally
expensive, but more detailed, track-structure
simulations. The predicted characteristics of various
classes of damage produced by electrons, protons and
α particles, such as average number of lesions
per DNA damage cluster and cluster length in base
pairs, are presented. A study examining the effects on
damage complexity of an extrinsic free radical
scavenger, dimethyl sulfoxide, is also presented. The
reported studies provide new information that will aid
efforts to characterize the relative biological
effectiveness of high-energy protons and other light
ions, which are sometimes used in particle therapy for
the treatment of cancer.



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"Those who corrupt the public mind are just as evil as those who steal from the public purse."
Adlai Stevenson

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com

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