GLOSSARY

Athermal - The absence of heat.

Brachytherapy - A method of radiation therapy in which an encapsulated source is utilized to deliver gamma or beta radiation at a distance up to a few centimeters either by surface, intracavitary, or interstitial application.

Curie (Ci) - The basic unit to describe the intensity of radioactivity in a sample of material. The curie is equal to 37 billion disintegrations per second.

Electromagnetic Radiation - Radiation consisting of associated and interacting electric and magnetic waves that travel at the speed of light. Examples: light, radio waves, gamma rays,
and x-rays.

Electron - An elementary particle with a unit negative electrical charge and a mass 1/1837 that of the proton.

Electrons surround the positively charged nucleus and determine the chemical properties of the atom.

Electron Volt (ev or eV) - The amount of energy gained by an electron when it is accelerated through an electric potential difference of one volt. It is equivalent to 1.603 X 10-12 erg.

Erg - A small unit of energy which can exert a force of one dyne (gm-cm/sec2) through a distance of one centimeter.

Frequency - The number of cycles per second of an alternating electric current.

Ionization - The process of removing one or more electrons from atoms or molecules, thereby creating ions.Isotope - One of two or more atoms with the same atomic number (the same chemical element) but with different atomic weights.

Joule - A unit of work or energy equal to 107 ergs.

Neutron - An uncharged elementary particle with a mass slightly greater than that of the proton and found in the nucleus of every atom heavier than hydrogen.Power Density - The ntensity of electromagnetic radiation power per unit area expressed as watts/cm2.

Proton - An elementary particle with a single positive electrical charge and a mass approximately 1,837 times that of the electron.

Radioactivity - The spontaneous decay or disintegration of an unstable atomic nucleus, usually accompanied by the emission of ionizing radiation.

Radioisotope - A radioactive isotope. An unstable isotope of an element that decays or disintegrates spontaneously, emitting radiation.

Radiation - The products of radioactivity such as gamma rays, beta particles, and alpha particles.Teletherapy - The treatment of disease with gamma radiation from a source located at a distance from the patient.

Watt - A unit of power equal to one joule per second.

Wavelength - The distance between any two similar points of two consecutive waves for electromagnetic radiation.