William Conrad Roentgen, a German physicist, discovered X–rays on November 8, 1895, through a series of fortunate coincidences while he was investigating the behavior of cathode rays (electrons) in high–energy cathode ray tubes.
By December 28, 1895 he had thoroughly investigated the properties of X–rays and prepared a manuscript which revolutionized the field of diagnosis. For this outstanding achievement, William C. Roentgen was awarded the first Nobel Prize for Physics in 1901.
Every part of the body, from head to toe, can be examined by X–rays. X–rays for certain parts of the body like the abdomen and lumbar spine need prior preparation (with bowel cleansing agents) and fasting to avoid misinterpretation. Other X–rays do not require any prior preparation.
All ionizing radiations are harmful hence, a radiation protection policy at all level is mandatory.
The harmful effects fall into two broad categories
Harmful to the person being irradiated, for example, carcinogenesis
Harmful to future generations. These are more frightening because they may not manifest for several generations and each new mutant constitutes a potential burden to society.
X–rays are produced by energy conversion when a fast–moving stream of electrons is suddenly decelerated in the target (usually tungsten or an alloy of tungsten) of an X–ray tube (a specially designed vacuum diode tube).
This energy is supplied to the tube by an X–ray generator connected to an incoming electric supply. X–rays pass through the body and carry information about the areas through which they have passed. The information is played on a special X–ray film/monitor for interpretation.
- Oral (gastro intestinal tract).
- Per rectal (large intestine).
- Per urethral/vaginal (genitourinary system).
- Laryngo–tracheal (lungs and bronchial tree).
- Intraarticular (joints).
- Intraspinal (spine).
When a pregnant woman requires an X–ray and the primary beam irradiates the foetus, at the outset care shared be taken to ascertain whether the examination is really indicated.
X–rays should be avoided as far as possible in the first trimester, during the period of organogenesis. The number of exposures and absorbed dose per exposure must be kept to a minimum. Lead protection devices and proper collumation of the X–ray beam must be employed.