Biophysical characterization of collimated and uncollimated fields in pencil beam scanning proton therapy.

This work demonstrated the dosimetric advantages of combining aperture with PBS coupled with lower DNA damage induction. A methodology for calculating dose in water derived from measurements with a silicon-based detector was also presented. This work is the first to demonstrate experimentally the increase in LET caused by combining PBS with aperture, and to assess the potential DNA damage which is the initial step in the cascade of events leading to the majority of radiation-induced biological effects.