The Science:

 

Radiation is a descriptor for energy (in the form of either particles or waves) travelling through space or another medium (Ralph, 2012, p. 6)

Ionisation is the process by which a stable atom or a molecule loses or gains an electron(s), thereby acquiring an electric charge or changing an existing charge. An atom or molecule with an electric charge is called an ion, which may behave differently, electrically and chemically, from a stable atom or molecule. The altered behaviour may lead to new possibly undesired molecules, a change in the conductive properties of the material in the vicinity of the ion, a release of energy, or a combination of these effects. In the human body, these effects may lead to changes in the structure or behaviour of cells. (Ralph, 2012, p.6)

 

Ionising radiation is emitted by a large range of natural materials, can be produced by everyday devices such as X-ray machines, and can also be emitted by unstable atoms. Atoms become unstable when they have the wrong amount of mass required to keep them stable, an excess of energy, or both. Unstable atoms are said to be radioactive.  

 

Absorbed dose: the amount of energy deposited by ionizing radiation in a unit mass of tissue. It is expressed in units of joule per kilogram (J/kg) and called “gray” (Gy).

 

Background radiation: ionizing radiation from natural sources, such as terrestrial radiation due to radionuclides in the soil or cosmic radiation originating in outer space.

 

Dose equivalent: a quantity used in radiation protection to place all radiation on a common scale for calculating tissue damage. Dose equivalent is the absorbed dose in grays times the quality factor. The quality factor accounts for differences in radiation effects caused by different types of ionizing radiation…The sievert (Sv) is the unit used to measure dose equivalent.

 

Effective dose: a dosimetric quantity useful for comparing the overall health effects of irradiation of the whole body. It takes into account the absorbed doses received by various organs and tissues and weighs them according to present knowledge of the sensitivity of each organ to radiation.  The unit of effective dose is the sievert (Sv); 1 Sv = 1 J/kg.

 

Half-life: the time any substance takes to decay by half of its original amount.

 

Ion: an atom that has fewer or more electrons than it has protons causing it to have an electrical charge and, therefore, be chemically reactive.

 

Ionization: the process of adding one or more electrons to, or removing one or more electrons from, atoms or molecules, thereby creating ions. High temperatures, electrical discharges, or nuclear radiation can cause ionization.

 

Ionizing radiation: any radiation capable of displacing electrons from atoms, thereby producing ions. High doses of ionizing radiation may produce severe skin or tissue damage.

 

Isotope: a nuclide of an element having the same number of protons but a different number of neutrons.

 

Radiation: energy moving in the form of particles or waves. Familiar non-ionising radiations are heat, light, radio waves, and microwaves. Ionizing radiation is a very high-energy form of electromagnetic radiation and particles.

 

Radioactive material: material that contains unstable (radioactive) atoms that give off radiation as they decay.

 

Radioactivity: the process of spontaneous transformation of the nucleus, generally with the emission of alpha or beta particles often accompanied by gamma rays. This process is referred to as decay or disintegration of an atom. (CDC, 2006)