Nanodosimetry: The missing link between radiobiology and radiation physics?

Abstract

It has long been assumed that the initiation of radiation induced damage to biological cells is dominated by inelastic interactions occurring at the location of the DNA or within its vicinity. The subcellular distribution of such interactions therefore plays a key role in the biological effectiveness of ionising radiation, where appropriate definitions of concepts such as radiation quality, which cannot be described by macroscopic quantities like absorbed dose, demand a study of particle track structure on the nanometre scale. This has presented an ongoing challenge in the metrology of ionising radiation to either supplement or replace the concept of absorbed dose with another quantity that accounts for the particle track structure within radiosensitive biological targets. A potential means for characterising radiation quality in this way may be that of nanodosimetry, a concept based on the frequency distribution of ionisation cluster sizes induced by single ionising particles interacting in nanometric volumes. This work gives a brief overview of nanodosimetric concepts and recent developments in the field of nanodosimetry.