Do We Need the LNT Hypothesis in Radiation Protection? Could a Traffic Light Model Be a Practicable Solution?

The linear no-threshold hypothesis (commonly known as LNT) has received increasing criticism in recent years. LNT assumes that the damaging effects of ionizing radiation, that is, stochastic effects such as cancer and genetic or teratogenic effects, increase linearly with dose and without a lower dose threshold. However, statistically verified data on the relationship between radiation and effects are only obtained for the range above 100 mSv y -1 , which is why linear extrapolation downward is carried out for the range of low radiation doses, i.e., below 100 mSv y -1 . Today's radiation protection systems are based on this principle. To place radiation protection on a different basis (that is, no longer on the LNT hypothesis), a traffic light model is proposed. It uses natural radiation exposure as a reference but maintains the existing limits and everything in radiation protection that has proven effective. What does change, however, is the lower end of the optimization range, according to the ALARA recommendation. For the justification of today's levels of exceptions, the precautionary principle is applied.