  The multiscale approach to the assessment of biodamage resulting upon
irradiation of biological media with ions is reviewed, explained and compared
to other approaches. The processes of ion propagation in the medium concurrent
with ionization and excitation of molecules, transport of secondary products,
dynamics of the medium, and biological damage take place on a number of
different temporal, spatial and energy scales. The multiscale approach, a
physical phenomenon-based analysis of the scenario that leads to radiation
damage, has been designed to consider all relevant effects on a variety of
scales and develop an approach to the quantitative assessment of biological
damage as a result of irradiation with ions. This paper explains the scenario
of radiation damage with ions, overviews its major parts, and applies the
multiscale approach to different experimental conditions. On the basis of this
experience, the recipe for application of the multiscale approach is
formulated. The recipe leads to the calculation of relative biological
effectiveness.
