Cell survival fraction estimation based on the probability densities of domain and cell nucleus specific energies using improved microdosimetric kinetic models

Sato, Tatsuhiko   ; Furusawa, Yoshiya*

Two computational models were established for the estimation on the basis of the concept of the microdosimetric kinetic (MK) model. They were designated as the double-stochastic microdosimetric kinetic (DSMK) and stochastic microdosimetric kinetic (SMK) models, where the former takes the stochastic natures of both domain and cell-nucleus specific energies into account, while the latter considers that of only cell-nucleus specific energy in order to reduce its computational time. Both DSMK and SMK models can reproduce the measured survival fractions even for high-LET and high-dose irradiations for which the conventional MK model predicts lower values due to the ignorance of the stochastic nature of the cell-nucleus specific energies. Those models are therefore capable of contributing to the better understanding of the mechanism of cell inactivation as well as the improvement of the accuracy of the treatment planning of charged-particle therapy.