The role of shock waves on the biodamage induced by ion beam radiation

Abstract

Background: Energetic ions irradiate the human body in different situations such as exposure to galactic cosmic rays and ion beam cancer therapy. Ions propagating through dense medium deposit energy on the nanometre scale, which cause large local doses in their tracks. This makes the mechanisms of the following biodamage different from that induced by photons. A distinctive feature of the scenario of radiation damage with ions is the potential hydrodynamic response of the liquid medium in the form of cylindrical shock waves around each ion's path. Review: Recent studies of the predicted cylindrical shock waves produced by swift ions propagating in liquid water or biological environments along with their effects on biological media are discussed in this review. The reasons for the onset of cylindrical shock waves in the vicinity of the ion's path are analysed theoretically, following the hydrodynamic approach to their description. Then, the classical molecular dynamics simulations of ion-induced shock waves are presented and discussed. Conclusion: The effects of shock waves on the scenario of radiation damage at different values of linear energy transfer are discussed in detail including the most recently simulated chemical effects. A number of ideas of experiments, in which the shock waves could be discovered, are presented, and ideas for the future developments in this field are conveyed.