Radiation is poorly understood in healthcare due to the LNT Model https://en.wikipedia.org/wiki/Linear_no-threshold_model.

The science is based on assumptions and extrapolation, they drew a linear plot line between rates of cancers at different levels of radiation, and then extended it down and to the left. But there is no actual experimental data showing a relationship between low dose radiation and cancer (Ironically there IS evidence that rates of overall cancers are lower in high altitude cities like Denver with more background radiation).