Cell-survival probability at large doses: an alternative to the linear-quadratic model

Area of Science:

• Radiation Biology
• Biophysics
• Nuclear Science

Background:

• The linear-quadratic (LQ) model is widely used for cell survival prediction but underestimates survival at high radiation doses.
• Accurate modeling of cell survival is crucial for radiation therapy and radiation protection.

Purpose of the Study:

• To develop a novel model for irradiated cell survival that rigorously accounts for microdosimetric effects.
• To assess the model's applicability across a range of radiation doses and types (low/high LET).
• To compare the new model's predictions with the conventional LQ model, especially at high doses.

Main Methods:

• Development of a new cell survival model incorporating detailed microdosimetric event accounting.
• The model does not assume a Poisson distribution for lesion formation.
• Application and comparison of the model with the LQ model across various dose ranges and radiation qualities.

Main Results:

• The developed model accurately predicts cell survival for low, intermediate, and high acute doses of low or high LET radiation.
• For small doses, the model's predictions align with the established linear-quadratic (LQ) model.
• At high doses, the new model demonstrates superior accuracy, whereas the LQ model significantly underestimates cell survival.

Conclusions:

• The new microdosimetry-based model offers a more accurate representation of irradiated cell survival than the conventional LQ model, particularly at high doses.
• The findings suggest that accounting for microdosimetric distributions, which can be approximated by Gaussian distributions at high doses, is essential for precise survival predictions.