BTW, doctors almost never use X-ray machines themselves, except some Cardiologists and Radiologists. It's almost always Radiologic Technologists doing the imaging.

The answer is that not all x-rays are created equal, and, not all RAYS are created equal. They have energies that vary widely. Microwaves, visible light, radio waves, UVA and UVB waves, x-rays, Gamma rays, etc. are all parts of the "electromagnetic spectrum" AND different types of these rays interact with matter differently. For instance, you can focus light through a magnifying glass, but not X-rays.

The issue here is that the airport scanners DO use a form of "radiation", but, not knowing how else to describe them, people say, "sort of like X-rays".

The scanners scanning the bags on trays use X-rays, and have protective shields. The body use a very specific energy of 30-300 GHz, capable of penetrating just a TINY thickness of matter before almost all essentially bounce off, though a few are absorbed on the very surface of the skin (just like heat and light can be) where the skin cells are already dead and can't be harmed. The imager counts on the ability of these mm-waves to get through most clothing, but then bounce off.

The one thing that is a good idea is closing your eyes, because the mm-waves won't penetrate your eyelids, but the very surface of your open eyeball is less protected.