- 1. The ionizing electromagnetic radiation emitted from a highly evacuated tube, resulting from the excitation of the inner orbital electrons by the bombardment of the target anode with a stream of electrons from a heated cathode. SYN: roentgen ray. Cf.:glass rays, under ray, indirect rays, under ray. 2. Ionizing electromagnetic radiation produced by the excitation of the inner orbital electrons of an atom by other processes, such as nuclear delay and its sequelae. 3. SYN: radiograph.
* * *X-ray n1) any of the electromagnetic radiations of the same nature as visible radiation but of an extremely short wavelength less than 100 angstroms that is produced by bombarding a metallic target with fast electrons in vacuum or by transition of atoms to lower energy states and that has the properties of ionizing a gas upon passage through it, of penetrating various thicknesses of all solids, of producing secondary radiations by impinging on material bodies, of acting on photographic films and plates as light does, and of causing fluorescent screens to emit light called also roentgen ray2) a photograph obtained by use of X-rays <a chest X-ray>X-ray adj
* * *(eksґra) see under ray.
Medical dictionary. 2011.