Sometimes seemingly dumb things are funny because they make you think a little bit and realize that it seems weird to someone who doesn't understand the context. This one is actually clever because without knowing the context of cumulative effects would be confused by the tech hiding behind a safety shield while telling you it is safe. The humor requires seeing it from someone else's perspective and having the knowledge of why it seems contradictory.
thanks. I was not sure how to respond to this. I suspect they understand that doctors or more likely the nurse or tech would be exposed to dozens of xrays a day instead of less than one a year but you never know.
Also we probably shouldn't tell them about background radiation.
For the curious a chest X-ray is about 0.02 mSv where your annual dose from background is about 2.4mSv, but this easily can be twice this if you live at high altitude or in an area with a higher level of radioactive minerals. Or if you are very lucky somewhere where both are a problem.
Hell airline crews are classified as radiation workers because the higher doses of cosmic radiation puts them over the threshold of on job exposure .
Every day, your body will probably generate at least one cell that would be cancerous if it wasn't for your immune system. If that probability goes up slightly as a result of mildly increased radiation that day, it likely won't overload the immune system's capacity to deal with it. If it is overexposed to radiation, eventually the greater probability of cancerous mutations exceeds the immune system's capacity.
It's probabilistic when it's 1 particle at a time.
At these rates of exposure from radiation it becomes primarily cumulative because at some point it's not a question of if you'll damage some cells or not, it's a question of if you're damaging them faster than they can repair or not.
There's still a probabilistic factor in when it leads to medically relevant damage and of what type, but it follows a pretty predictable scale dependent on prior dose