Definitions of Terms Used in this Manual

 ALARA - Acronym for "As Low As Reasonably Achievable", a basic concept of radiation protection that specifies that radioactive discharges to the environment and radiation exposure to personnel be kept as far below regulatory limits as feasible.


Airborne radioactive material - any radioactive material dispersed in the air in the form of dusts, fumes, mists, vapors or gases.


Airborne radioactivity area - (1) any room, enclosure, or operating area in which airborne radioactive material exists in concentrations in excess of the amounts specified in RHA 3.53, Appendix B, Table I, Column 3 of S.C. DHEC Radioactive Materials Regulation 61-63 title A ; or (2) any room, enclosure, or operating area in which, averaged over the number of hours in any week during which individuals are in the area, exceed 25 percent of the amounts specified in RHA 3.53, Appendix B, Table I, Column 3 of Radioactive material Regulations 61-63 Title A.


ALI (Annual Limit on Intake) - The derived limit for the amount of radioactive material taken into the body of an adult worker by inhalation or ingestion in a year.  ALI is the smaller value of intake of a given radionuclide in a year by the reference man that would result in a committed effective dose equivalent of 5 rem (0.05 Sv) or a committed dose equivalent of 50 rems (0.5 Sv) to any individual organ or tissue.


BRH - As used in this manual:  South Carolina Department of Health and Environmental Control - Bureau of Radiological Health.


Calendar quarter - not less than 12 consecutive weeks nor more than 14 consecutive weeks. The first calendar quarter of each year shall begin in January; and subsequent calendar quarters shall be such that no day is included in more than one calendar quarter or omitted from inclusion within a calendar quarter. No licensee shall change the method observed by him of determining calendar quarters except at the beginning of a calendar year.


Contamination - The deposition of unwanted radioactive material on the surfaces of structures, areas, objects, or personnel.


Contaminated area - Any area where there exist loose surface (removable) contamination greater than or equal to:

  1.         200 disintegrations per minute beta/gamma or

  2.         20 disintegrations per minute alpha


Controlled Area - a defined area in which the occupational exposure of personnel to radiation or radioactive material is under the supervision of an individual in charge of radiation protection. 


Curie - The basic unit used to describe the intensity of radioactivity in a sample of material.  That amount of radioactivity that will disintegrate of the rate of 3.7 E 10 disintegrations per second or 2.22 E 12 disintegrations per minute (dpm).

  Commonly used fractions of the curie:

  1.         Pico Curie - one trillionth part =        2.22 dpm

  2.         Nano Curie - one billionth part =       2.22 E 3 dpm

  3.         Micro Curie - one millionth part =     2.22 E 6 dpm

  4.         Milli Curie- one thousandth part =    2.22 E 9 dpm


DAC (Derived Air Concentration) - The concentration of a given radionuclide in air which, if breathed by the reference man for a working year of 2,000 hours under conditions of light work (inhalation rate 1.2 cubic meters of air per hour), results in an intake of one ALI.


Dpm - The number of radioactive disintegrations per minute, which is determined by: (observed cpm - background cpm) / instrument efficiency     =   DPM


Dose rate - The radiation dose delivered per unit of time.  Measured, for example, in Rem per hour.


Exposure - The absorption of radiation or ingestion of a radionuclide.  Acute exposure is generally accepted to be a large exposure received over a short period of time.  Chronic exposure is exposure received during a lifetime. 


"Bureau" or BRH - the South Carolina Department of Health and Environmental Control - Bureau of Radiological Health.


Gamma ray - High energy, short wavelength electromagnetic radiation emitted from the nucleus of an atom.  Gamma radiation frequently accompanies alpha and beta emissions.


Half-life - The time in which half the atoms of a particular radioactive substance disintegrate to another nuclear form. 


Half value thickness - The thickness of any given absorber that will reduce the intensity of a beam of radiation to one-half its initial value.  Tenth value thickness - same as above but with reduction to one-tenth the original value.


High Radiation Area - means any area, accessible to individuals, in which there exists radiation at such levels that the whole body could receive in any one hour a dose in excess of 100 millirem.


Ionizing radiation - Any radiation capable of displacing electrons from atoms or molecules, thereby producing ions:  alpha, beta, gamma, X-rays, and neutrons.

Isotope - One of two or more atoms with the same number of protons, but different numbers of neutrons in their nuclei.  Carbon-12, carbon-13, and carbon-14 are isotopes of the element carbon, the numbers denoting the approximate atomic weights.  Isotopes have very nearly the same chemical properties, but  different physical properties (for example carbon-12 and -13 are stable, carbon-14 is radioactive.)  For the purposes of this manual the word "isotope" means "radioactive or radio isotope".


License - except where otherwise specified, means either a general license or specific license issued pursuant to DHEC Radioactive material Regulations.


Natural radioactivity - radioactivity of naturally occurring nuclides.


Radionuclide - a radioisotope.  For the purposes of this manual the word "nuclide" means radionuclide or radioisotope.


Occupational dose - exposure of an individual to radiation (i) in a restricted area; or (ii) in the course of employment in which the individual's duties involve exposure to radiation; provided, that occupational dose shall not be deemed to include any exposure of an individual to radiation for the purpose of medical diagnosis or medical therapy of such individual.


Primary use area - any area such as a table, bench top or portion of a bench top that is set aside for the staging and manipulation of potentially contaminated items or unsealed source material.  These areas will be delineated by placing two inch wide yellow and magenta tape around the perimeter of the area and a readily visible sign bearing the radiation trifoil and the words "CAUTION CONTAMINATED AREA".  Use of these areas will assist in segregation of contaminated and non-contaminated items and help to minimize materials stored in the fume hood.


Personnel monitoring equipment - devices designed to be carried or worn by an individual for the purpose of measuring the dose an individual receives (e.g. film badges, film rings, pocket chambers, pocket dosimeters, thermoluminescent dosimeters, etc.).


Radiation - gamma rays, X‑rays, alpha and beta particles, high‑speed electrons, neutrons, and other nuclear particles; but not sound or radio waves, or visible, infrared, or ultra‑violet light.


Radiation Area - any area, accessible to individuals, in which there exists ionizing radiation at such levels exceeding those listed in Title A, RHA 1.2.24.  Any area in which there exist ionizing radiation at such levels such that the whole body could receive in any one hour a dose in excess of 5 millirem, or in any 5 consecutive days a dose in excess of 100 millirem.


Radiation Safety Officer (RSO) - any person directly responsible for protection against radiation.  At Clemson the RSO is J.L. Addis.


Radioactive material - any material, solid, liquid, or gas, which emits radiation spontaneously.


Restricted area - any area to which access is controlled by the licensee for purposes of protection of individuals from exposure to radiation and radioactive materials. "Restricted area" shall not include any areas used for residential quarters, although a separate room or rooms in a residential building may be set apart as a restricted area.


Sealed source - radioactive material that is permanently bonded or fixed in a capsule or matrix designed to prevent release and dispersal of the radioactive material under the most severe conditions which are likely to be encountered in normal use and handling.


Smear  - A piece of filter paper or cloth disk which is wiped over a surface and analyzed to determine if the surface is contaminated with loose radioactive material (reported in units of dpm / 100 cm).


Source of radiation - any radioactive material, or any device or equipment capable of producing or emitting radiation.


Survey - an evaluation of the radiation hazards incident to the production, use, release, disposal, or presence of sources of radiation under a specific set of conditions. When appropriate, such evaluation includes a physical survey of the location of materials and/or equipment and measurements of levels of radiation or concentrations of radioactive material present.


Unrestricted area - any area access to which is not controlled by the licensee for purposes of protection of individuals from exposure to radiation and radioactive materials, and any area used for residential quarters.


Whole body - the entire body, or a major portion thereof, or the head and trunk, or the active blood forming organs, or the lens of the eyes or the gonads. Whole body does not refer to the skin of the whole body.




Dose - the quantity of radiation absorbed, per unit of mass, by the body or by any portion of the body.  When these regulations specify a dose during a period of time, the dose means the total quantity of radiation absorbed, per unit of mass, by the body or by any portion of the body during such period of time. Several different units of dose are in current use. Definitions of units as used in DHEC regulations are set forth in the following paragraphs of Title-A 1.3.2 and 1.3.3


Rad - Radiation Absorbed Dose: a measure of the dose of any radiation to body tissues in terms of the energy absorbed per unit mass of the tissue. One rad is the dose corresponding to the absorption of 100 ergs per gram of tissue. (One millirad [mrad] = 0.001 rad)


Rem - a measure of the dose of any radiation to body tissue in terms of its estimated biological effect relative to a dose of one roentgen (R) of X-rays. (One millirem [mrem] =0.0010 rem.) The relation of the rem to other dose units depends on the biological effect under consideration and upon the conditions of irradiation. For the purpose of these regulations, any of the following is considered to be equivalent to a dose of one rem:

  A dose of 1 R due to X - or gamma radiation;

  A dose of 1 rad due to x -, gamma, or beta radiation;

  A dose of 0.1 rad due to neutrons or high-energy protons.




RADIOACTIVE WASTE :  Any waste material that contains:

  1.         Radioactively contaminated laboratory trash such as glassware, paper, lab clothing, gloves, culture dishes, syringes, etc.

  2.         Animal carcasses containing residual radioactive tracers.

  3.         Sealed radioactive sources used for instrument response checks or research.   Notify the R.S.O. before disposing of any sealed sources.  Do not dispose of sealed sources in the regular laboratory rad waste. There are special requirements for their disposal.

  4.         Aqueous or organic solutions containing radioactive contaminants.


LIQUID RADIOACTIVE WASTE  - Waste containing radioactive materials in aqueous or organic solutions.


DRY ACTIVE WASTE  - Dry laboratory trash to include:  paper, gloves, glassware, utensils, etc.


LIQUID SCINTILLATION WASTE  - Scintillation solvents, fluors and radioactive material and/or the containers that held them.


SHORT HALF-LIFE WASTE  - Wastes containing radioactive materials with half-lives of 65 days or less.


LONG HALF-LIFE WASTE  - Wastes containing radioactive materials with half-lives of greater than 65 days.


WASTE CLASSIFICATIONS  - (from campus waste disposal form)

  1. DAW - Dry active waste: glassware, plastic, paper etc. (no liquids).

  2. BOL - Bulk organic liquids:  liquid organic solvents (toluene, hexane, benzene, dioxane)

  3. A/T-P/T     Animal tissue plant tissue

  4. LSV  - liquid scint vials of glass or plastic that contain or have contained organic liquids.