FIAS Scientific Report 2011 - Frankfurt Institute for Advanced Studies ...

Multiscale approach to the physics of ion beam cancer therapy
Collaborators: E. Surdutovich 1 , A.V. Solov’yov 2 , A.V. Yakubovich 2 , W. Greiner 2
1 Oakland University, Michigan, USA, 2 Frankfurt Institute for Advanced Studies
Short description:
The multiscale approach to the radiation damage induced by irradiation with ions is aimed to the phenomenonbased
quantitative understanding of the scenario from incidence of an energetic ion on tissue to the cell death.
This approach joins together many spatial, temporal, and energetic scales involved in this scenario. The success
of this approach will provide the phenomenological foundation for ion-beam cancer therapy, radiation protection
in space, and other applications of ion beams. Main issues addressed by the multiscale approach are ion
stopping in the medium, production and transport of secondary particles produced as a result of ionization and
excitation of the medium, interaction of secondary particles with biological molecules, most important with
DNA, the analysis of the induced damage, and evaluation of probabilities of subsequent cell survival or death.
This approach is interdisciplinary, since it is based on physics, chemistry, and biology. Moreover, it spans over
several areas within each of these disciplines.
Thermo-mechanical pathways of DNA damage
A number of different agents cause DNA damage as a consequence of irradiation. These include interactions
of a DNA molecule with secondary electrons, holes and free radicals. Within this project we discuss the DNA
damage due to thermal and mechanical effects which accompany the ion propagation.
• We have performed full-atom molecular dynamics simulations of the heat spike in the water medium caused
by a heavy ion in the vicinity of its Bragg peak. High rate of energy transfer from an ion to the water molecules
leads to the rapid increase of temperature in the vicinity of the ion trajectory. As a result of an abrupt increase
of the temperature we observe the formation of the nanoscale shock wave propagating through the medium.
• We investigate the thermomechanical damage caused by the shock wave to the nucleosome located in the
vicinity of heavy ion trajectory. We observe the substantial deformation of the DNA secondary structure. We
show that the produced shock wave can lead to the thermomechanical breakage of the DNA backbone covalent
bonds and present estimates for the number of such strand breaks per one cell nucleus.
Related publications in 2011:
Figure: Structure of the nucleosome 150 fs after the carbon
ion propagation. Water molecules initially located
within 1 nm from the ion’s track are shown by spheres. It
is seen as substantial distortion of the nucleosome structure
caused by the propagation of the shock wave.
1. A.V. Yakubovich, E. Surdutovich and A.V. Solov’yov, Atomic and molecular data needs for radiation
damage modeling: Multiscale approach, AIP Conf. Proc. 1344, 230-238 (2011).
2. A.V. Yakubovich, E. Surdutovich, A.V. Solov’yov, Thermomechanical damage of nucleosome by
the shock wave initiated by ion passing through liquid water, Nucl. Instrum. Meth. B,
doi:10.1016/j.nimb.2011.10.069 (2011).
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