Challenges in radiobiology - technology duality as a key for a risk-free α/β ratio.

Since radiotherapy discovery, prediction of biological response to ionizing radiation remains a major challenge. Indeed, several radiobiological models appeared through radiotherapy history. Nominal single dose so popular in the 1970s, was tragically linked to the dark years in radiobiology by underestimating the late toxicity of the high-dose fractions. The actual prominent linear-quadratic model continues to prove to be an effective tool in radiobiology. Mainly with its pivotal α/β ratio, which gives a reliable estimate of tissues sensitivity to fractions. Despite these arguments, this model experiences limitations with substantial doubts of α/β ratio values. Interestingly, the story of radiobiology since X-ray discovery is truly instructive and teaches modern clinicians to refine fractionation schemes. Many fractionation schemes have been tested with successes or dramas. This review retraces radiobiological models' history, and confronts these models to new fractionation schemes, drawing a preventive message.