A Logarithmic Formula to Describe the Relationship between the Increased Radiosensitivity at Low Doses and the Survival at 2 Gray

Objectives: intrinsic radiosensitivity at doses used in radiotherapy is linked to hypersensitivity (hrs)and increased radio resistance (irr) at low doses. the aim of this study was to explore this relationship. methods: survival curves for 18 human tumour cell lines were analysed, using two models to fit the data points in order to extract the necessary parameters relevant for this study. results: the irr ratio αs/αr versus the survival at 2 gray (gy) can be described by a logarithmic relation which leads to a series of straight lines. conclusion: the relationship obtained implies that there is a direct link between hrs/irr and survival at clinically relevant doses of 2 gy.