X-RADIATION

The Uses of X-RADIATION

Spectrometry; structure determination of molecules, cancer therapy, diagnostic medicine, nondestructive testing of metals, identification of original paintings, preservation of foods.

Definition

Electromagnetic radiation of extremely short wavelength (0.06–120 A), emitted as the result of electron transitions in the inner orbits of heavy atoms bombarded by cathode rays in a vacuum tube. Those of the shortest wavelength have the highest intensity and are called “hard” X-rays. X-radiation was discovered by Roentgen in 1898. Its properties are (1) penetration of solids of moderate density, such as human tissue but retardation by bone, barium sulfate, lead, and other dense materials. (2) Action on photographic plates and fluorescent screens. (3) Ionization of the gases through which they pass. (4) Ability to damage or destroy diseased tissue; there is also a cumulative deleterious effect on healthy tissue.

Hazard

Overexposure can permanently damage cells and tissue structures; effect is cumulative.

Agricultural Uses

X-rays are electromagnetic radiation of extremely short wavelength (0.06 to 120 A), emitted as a result of electron transitions in the inner orbits of heavy atoms bombarded by cathode rays in a vacuum tube. Those of the shortest wavelength have the highest intensity and are called 'hard' x-rays. x-radiation was discovered by Roentgen in 1898. x-rays have the following properties: (i) They penetrate solids of moderate density, such as human tissue; they are retarded by bone, barium sulphate, lead and other dense materials. (ii) They act on photographic plates and fluorescent screens. (iii) They ionize gases through which they pass. (iv) x-rays damage or destroy diseased tissue. There is also a cumulative deleterious effect on healthy tissue.
X-rays find wide use in medicine both for diagnosis and treatment and in engineering where radiographs are used to show up minute defects in structural members. X-ray tubes must always be carefully shielded because the radiation causes serious damage to living tissue.