Originally Posted by greentips

OK, let's have us a look, shall we:


Now, let's talk about the physics of photon (x-ray)/matter interactions.
There are, in the diagnostic energy ranges (less than around 150 kVp (peak kilovolts), several x-ray-matter interactions: Rayleigh Scattering (coherent scatter), in which an incident x-ray path is altered by interaction with an orbital electron. No ionization event but the x-ray path is changed. This is why the sky is blue.

Next, Photo-electron events in which an x-ray interacts with and excites an inner shell electron, imparting (in accordance with quantum mechanics) energy to a.) either eject the electron from the atom, or b.) raise the electron energy to a higher orbital. The energy is eventually released in the form of a second photon of "characteristic" energy specific to each orbital and each atom.

Next, there is the Compton scatter event. This is an interaction with an orbital, usually outer shell electron which causes the ejection of the electron from the atom (ionization event) and the loss of energy from the x-ray in proportion to the energy imparted to cause the ionization event. These events include both energy to matter conversion and change in kinetic energy ( E=mc^2 and 1/2 mv^2).

There are other events at much higher energies which are not pertinent, but as you can see, your statement, "ionizing radiation adds to the structure of an atom" is incorrect. An x-ray can produce electrons if its energy is above 1 mega-electron volt (or more precisely 1.022 MeV, through an interaction called pair production in which an electron and an anti-electron are produced, but this is an independent energy to matter conversion reaction. A reverse interaction when an anti-electron meets an electron which causes an annihilation reaction converting matter and anti-matter directly to energy and the release of a pair of 0.511 MeV photons. These interactions do not change the structure of an atom.

There are even more esoteric reactions, such as electron capture events, but these release gamma rays and are the result of a radioactive state transition and not the result of x-ray exposure.