Track structure and microdosimetry of proton beams

Sato, Tatsuhiko   

Ionizing radiation heterogeneously deposits energy in matter via atomic interactions such as ionization and excitation. This heterogeneity complicatedly depends on the type and energy of ionization radiation, and influences the biological effect of the radiation exposure. Thus, the biological effects are expected to be different with radiations imparting the energy even for the same absorbed dose. In this chapter, a review of the definitions of microdosimetric quantities is given. Examples of calculated track structures and microdosimetric quantities of several mono-energetic radiations are shown for discussion. Then, past studies on the applications of microdosimetry in proton therapy are briefly reviewed and summarized.