Uncertainty linked to weak doses:
In the field of the small and the very small doses, the absence of precise data makes all cause-effect links unreliable. Some radioprotectionists question the validity of the ‘official’ relationship (represented here by the straight line "ICRP" linking the origin to data samples at much higher doses which are outside the graph). They advocate a ‘threshold’ model – with no discernible risks below a certain minimum dose. A third model, known as hormesis, assumes that low doses of radiation may even be beneficial. These models are loosely represented on the graph above – the scales on the two axes have not been specified.