Comparison of six different models describing survival of mammalian cells after irradiation.

Six different cell-survival models have been compared. All models are based on the similar assumption that irradiated cells are able to exist in one of three states. SA is the state of a totally repaired cell, in state SC the cell contains lethal lesions and in state SB the cell contains potentially lethal lesions i.e. those which either can be repaired or converted into lethal lesions. The differences between the six models lies in the different mathematical relationships between the three states. To test the six models, six different sets of experimental data were used which describe cell survival at different repair times after irradiation with sparsely ionizing irradiation. In order to compare the models, a goodness-of-fit function was used. The differences between the six models were tested by use of the nonparametric Mann-Whitney two sample test. Based on the 95% confidence limit, this required separation into three groups.