EPJ D - Ions that love DNA to bits

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Published on 22 October 2010

Low energy carbon ions have been directed to small DNA strand. The results provide new information of the mechanisms of DNA damage during ion beam therapy, also called hadron therapy.

The clinical success of hadron therapy, where proton and ions with energies of below 150 MeV are used in the treatment of many tumour types, has heightened the interest in the fundamental interactions between ion beams and with biomolecules. Along the radiation track of the primary heavy particle, a large number of ions lose their energy due to inelastic scattering and many low energy secondary fragments (electrons and ions) are produced within the tissue. If such secondary species are formed in the close vicinity of the nucleus of living cell, they can cause significant DNA damage. However the molecular mechanisms by which such damage occurs remains unclear and is a clear limitation to the further development of ion beam therapy.

The recent work published in EPJ D used a mass spectrometer to reveal the length and chemical composition of the fragments caused by carbon ion beam. The fragmentation yield mainly depends on the nucleobase composition and not on the other components of DNA, i.e. sugar and phosphate group. This result tells us which parts of the DNA are most susceptible to such radiation damage and may then be used to improve radiotherapy techniques.