ABSTRACT
A new frontier for particle therapy is now represented by multiple ion treatments. While particle therapy with ions heavier than protons is still representing a small portion as compared to the number of patients receiving and facilities applying proton therapy. In ion-beam therapy treatment planning, a biological dose, which is defined as the product of absorbed dose and relative biological effectiveness, is optimized for the individual clinical cases. The RBE is a ratio of dose for a reference radiation to that for the radiation of interest to yield a defined biological effect. Carbon ion beams provide high-precision dose delivery accompanied by lower LET in the entrance channel and higher LET increasing exponentially towards the distal-end. In general, carbon ion LET compared to protons is higher, yielding more complex DNA damage, increased cell-kill per unit dose and hence potential for improved tumor control, especially for radio-resistant indications.
