Actually (presuming your genetics is typical of the population and you don't already live on a high mountain, in an otherwise high radiation area, or spend much of your time on airliners in flight), a low level of additional ionizing radiation IS good for you.
Do you have a source for this? A bit of googling turned up nothing to support it, and quite a bit from scientists who disagree, including this paper: https://www.pnas.org/content/1... Excerpt (emphasis mine): "High doses of ionizing radiation clearly produce deleterious consequences in humans, including, but not exclusively, cancer induction. At very low radiation doses the situation is much less clear... First, what is the lowest dose of x- or y-radiation for which good evidence exists of increased cancer risks in humans? The epidemiological data suggest that it is 10–50 mSv for an acute exposure and 50–100 mSv for a protracted exposure. Second, what is the most appropriate way to extrapolate such cancer risk estimates to still lower doses? Given that it is supported by experimentally grounded, quantifiable, biophysical arguments, a linear extrapolation of cancer risks from intermediate to very low doses currently appears to be the most appropriate methodology."
Kill Ugly Processor Architectures - Karl Lehenbauer