Fast ions exhibit a unique dose-distribution when interacting with human tissue. At a well-
defined depth, ions are slowed down to MeV energies and cell killing is most effective due
to maximum linear energy transfer and radiobiological effectiveness. Such volume
sensitivity renders ion-therapy a superior tool for a number of localized tumors, in some
cases decreasing the yearly risk of radiation induced development of lethal secondary
tumors by one order of magnitude!
Molecular mechanisms underlying biological radiation action still remain unclear.
Particularly the exceptional cell killing efficiency of heavy ions and protons is largely
unexplored on the molecular level. In this talk I will briefly introduce various aspects of
bio-molecular radiation action. Emphasis will then be laid on ion induced fragmentation
dynamics of the smallest building blocks of life such as DNA building blocks and amino
acids. The results for instance indicate that the particularly fatal clustered DNA strand
breaks are easily induced by proton or heavy ion impact. Finally, the current trend towards
investigation of complex nanosolvated biomolecules will be discussed.
