A BENCHMARK OF CELL-SURVIVAL MODELS USING SURVIVAL CURVES FOR HUMAN-CELLS AFTER COMPLETION OF REPAIR OF POTENTIALLY LETHAL DAMAGE

Six models of radiation action (the linear-quadratic model, the multit arget model with initial slope, the repair-misrepair model, the lethal -potentially lethal model, the cybernetic model, the saturable repair model) were tested for their goodness of fit to survival curves for hu man cells. Fifty-three survival curves for human cells irradiated in p lateau phase and after completion of repair of potentially lethal dama ge (PLD) provided the experimental basis for the tests. Three criteria were considered. The capacity to describe the survival data was estim ated, using the error left unexplained by the model. A validation of m odels was achieved by consideration of the mean residual squared error s. The ability of the parameters to characterize survival curves was i nvestigated, studying their variation within and among curves. The mod els were not equivalent, whatever the test. The saturable repair model and the multitarget with initial slope model gave the most accurate d escription of survival data. The linear-quadratic model had the most r eliable parameters, so that comparisons of the cell survival curves co uld be made advantageously. The cybernetic model and the lethal-potent ially lethal model were found inappropriate for the analysis of surviv al curves for human cells after completion of PLD repair.