Radiobiology Cell Survival

The loss of proliferative potential of a cell is often equated to cell kill, and many studies of the cellular effects of radiation (both ionising and non-ionising) utilise this definition of cell kill to define cell survival. To measure cell survival using this paradigm, a cell culture that has been exposed to a known dose of radiation is cultured and, at a predefined time post irradiation, the number of reproducing cells counted. For ionising radiation, it is generally assumed that any small dose is detrimental to cell survival, which manifests as a broad sigmoid function describing survival as a function of dose, illustrated in Figure 7.1. The resulting survival curve determines the radiosensitivity of the cell, which can be determined from the slope of this curve or the curve shown in Figure 5.16.