Impact of microdosimetric modeling on computation of relative biological effectiveness for carbon ion radiotherapy

炭素線治療における生物学的効果比(RBE)の計算に対するマイクロドジメトリモデルの影響

Hartzell, S.*; Furutani, K. M.*; Parisi, A.*; 佐藤 達彦   ; 加瀬 優紀*; Deglow, C.*; Friedrich, T.*; Beltran, C. J.*

Hartzell, S.*; Furutani, K. M.*; Parisi, A.*; Sato, Tatsuhiko; Kase, Yuki*; Deglow, C.*; Friedrich, T.*; Beltran, C. J.*

Microdosimetry is essential in particle therapy for understanding the biological effects of treatments by quantifying energy depositions within microscopic volumes. The calculation of the microdosimetric distributions can be carried out with physical models such as the Kiefer-Chatterjee (KC) track structure function and the Sato analytical microdosimetric function (AMF). Comprehensive comparisons across these physical models are lacking. The AMF is calculated for spherical domains, while the KC is traditionally calculated for a cylindrical domain. This study introduces a novel version of the KC function for spherical domains, allowing a direct comparison with AMF. The influence of each function on the calculation of the relative biological effectiveness (RBE) in carbon ion radiotherapy (CIRT) was evaluated.