Contents
10.1 Radiation Protection Program Glossary
A
Absorbed Dose: The energy imparted by ionizing radiation per unit mass of irradiated material. The units of absorbed dose are the gray (Gy) or the rad.
Activity: The rate of disintergrations or transformation or decay of radioactive material. The units are the becquerel (Bq) and the curie (Ci).
Airborne radioactive material: Any radioactive material dispersed in the air in the form of dusts, fumes, particulates, mists, vapors, or gases.
Airborne Radioactivity Area: Area in which airborne radioactive materials exist in concentrations in excess of the DAC for that isotope or 0.6% of the ALI in one week
ALARA: As low as reasonably achievable
Alpha Particle: A charged particle emitted from the nucleus of an atom having a mass and charge equal in magnitude of a helium nucleus (i.e. 2 protons and 2 neutrons).
Annual limit on intake (ALI): The derived limit for the amount or radioactive material taken into the body of an adult worker by inhalation or ingestion in a year. An ALI is the smaller value of intake of a given radionuclide in a year that would result in a committed effective dose equivalent of 5 rem or a committed dose equivalent of 50 rem to any individual organ or tissue.
Atom: Smallest particle of an element that cannot be divided or broken up by chemical means. It consists of a central core called the nucleus, which contains protons and neutrons. Electrons revolve in orbits surrounding the nucleus.
Atomic Mass: The mass of a neutral atom of a nuclide, usually expressed in terms of “atomic mass units.” The “atomic mass unit” is one‑twelfth the mass of one neutral atom of C-12; equivalent to 1.6604X10E‑24 gm (Symbol: u).
Atomic Number: The number of protons in the nucleus of an atom and the number of electrons on an electrically neutral atom (Symbol: Z)
Atomic Weight: The weighted mean of the masses of the neutral atoms of an element expressed in atomic mass units.
Attenuation: The process by which a beam of radiation is reduced in intensity when passing through some material. It is the combination of absorption and scattering processes and leads to a decrease in flux density of a beam projected through matter.
B
Background Radiation: Radiation from cosmic sources, terrestrial sources and other naturally occurring radioactive materials, including radon.
Barriers, Protective: Barriers of radiation‑absorbing material, such as lead, concrete, and plaster, used to reduce radiation exposure.
Barriers. Primary Protective: Barriers sufficient to attenuate the useful beam to the required degree.
Barriers, Secondary Protective: Barriers sufficient to attenuate stray radiation to the required degree.
Beam: An unidirectional or approximately unidirectional flow of electromagnetic radiation or of particles.
Becquerel (Bq): SI unit for Activity. One Bequerel equals 27 picoCuries or 1 disintegration per second.
Beta Particle: A charged particle emitted from a nucleus during radioactive decay. A negatively charged beta particle is identical to an electron. A positively charged beta particle is called a positron.
Bioassay: Determination of kinds, quantities or concentrations of radioactive material in the human body either by direct measurement or analysis of material excreted or removed from the body.
Biological Halflife: The time required for the body to eliminate by natural processes, half the amount of a substance which has entered it.
Bremsstrahlung: Secondary photon radiation produced by deceleration of charged particles through matter.
C
Calibration: The check or correction of the accuracy of a measuring instrument to assure proper operational characteristics.
Carrier: A quantity of non‑radioactive or non‑labeled material of the same chemical composition as its corresponding radioactive or labeled counterpart. When mixed with the corresponding radioactive labeled material, so as to form a chemically inseparable mixture, the carrier permits chemical (And some physical) manipulation of the mixture with less label or radioactivity loss than would be true for the undiluted label or radioactivity.
Carrier Free: An adjective applied to one or more radioactive isotopes of an element in minute quantity, essentially undiluted with stable isotope carrier.
Collective Dose: The sum of the individual doses received in a given period of time.
Committed Dose Equivalent (HT,50): The dose equivalent to organs or tissues of reference “T” that will be received from an intake of radioactive material by an individual during the 50 year period following the intake.
Committed Effective Dose Equivalent (HE,50): The sum of the products of the weighting factors applicable to each body organ or tissue irradiated and the Committed Dose Equivalent to each of these organs or tissues.
(Sum of all WTHT,50)
Contamination (radioactive): Deposition of radioactive material in any place where it is not desired, particularly where its presence may be harmful. The harm may be vitiating the experiment or procedure, or in actually being a source of danger to personnel.
Controlled Area: Any area in which the access is controlled for the purpose of protecting individuals from exposure to radiation or radioactive materials. Synonymous to “Restricted Area”.
Control Unit: Radiation protection terminology for a quantity of radioactive material. Each radioisotope is assigned a control unit activity on the basis of the degree of hazard it presents to laboratory personnel.
Count, Radiation: The external indication of a device designed to enumerate ionizing events. It may refer to a single detected event or to the total number registered in a given period of time. The term often is erroneously used to designate a disintegration, ionizing event, or voltage pulse.
Count, Spurious: In a radiation counting device, a count caused by any agency other than radiation.
CPM: Counts per minute.
Curie: The special unit of activity. One curie equals 3.7E10 nuclear transformations per second. (Abbreviated Ci.) Several fractions of the curie are in common usage.
D
Daughter: Synonym for decay product.
Decay, Radioactive: Disintegration of the nucleus of an unstable nuclide by spontaneous emission of charged particles and/or photons.
Decay Constant: The fraction of the number of atoms of a radioactive nuclide which decay in unit time ( Symbol: See Disintegration Constant).
Declared Pregnant Woman (DPW): A woman who has voluntarily informed her employer, in writing, of her pregnancy.
Deep Dose Equivalent (Hd): The dose equivalent for external whole body exposure at a tissue depth of 1 centimeters.
Decontamination: Removal of unwanted radioactive material from an object or personnel.
Decontamination Factor: The ratio of the amount of undesired radioactive material initially present to the amount remaining after a suitable processing step has been completed. Decontamination factors may refers to the reduction of some particular type of radiation or to the gross measurable radioactivity.
Derived Air Concentration (DAC): The concentration of a given radionuclide in air which if breathed by the reference man for a working year if 2,000 hours under conditions of light work (i.e.: inhalation rate of 1.2 cm3/hr) would result in an intake of one (1) ALI.
Detector, Radiation: Any device for converting radiant energy to a form more suitable for observation; an instrument used to determine the presence, and sometimes the amount, of radiation.
Disintegration Constant: The fraction of the number of atoms of a radioactive nuclide which decay in unit time: in the equation N=Noe‑t where No is the initial number of atoms present, and N is the number of atoms present after some time, t.
Dose: A generic term denoting absorbed dose, dose equivalent, effective dose equivalent, committed dose equivalent, committed effective dose equivalent, and total effective dose equivalent.
Dose Equivalent (HT): The product of the absorbed dose in tissue, quality factor, and other necessary modifying factors. The units of Dose Equivalent are Sievert (SV) and rem
Dose Equivalent, Maximum Permissible: The greatest dose equivalent that a person or specified part thereof shall be allowed to receive in a given period of time.
Dose Rate: Radiation dose delivered per unit time.
Dosimeter: Instrument to detect and measure accumulated radiation exposure. For example a film badge or ring TLD.
DPM: Disintegrations per minute.
Dry Run: A trial exercise in which a procedure involving radiation or radioactive material is simulated without actually using radiation or radioactive material. A dry run allows the experimenter to examine the procedure for changes which would minimize radiation exposure and contamination.
E
Effective Dose Equivalent (HE): The sum of the products of the dose equivalent to an organ or tissue (HT) and the weighting factor (WT) applicable to each of the body organs or tissues irradiated ( Sum of all WTHT)
Electron: An elementary particle with a unit negative charge. Electrons surround the positively charged nucleus and determine the chemical properties of the atom.
Electron Volt: A unit of energy equivalent to the energy gained by an electron in passing through a potential difference of one volt. Larger multiple units of the electron volt are frequently used: keV for thousand or kilo electron volts; MeV for million or mega electron volts. (Abbreviated: eV, 1 eV+1.6E‑12 erg.)
Electron Capture: A mode of radioactive decay involving the capture of an orbital electron by its nucleus. Capture from a particular electron shell is designated as “K‑electron capture”, ” “L‑electron capture,” etc.
Element: A category of atoms all of the same atomic number.
Embryo/Fetus: The developing human organism from conception until the time of birth (embryo: 2-8 weeks gestation, fetus: end of week 8 to term).
Energy Dependence: The characteristic response of a radiation detector to a given range of radiation energies or wave lengths compared with the response of a standard free‑air chamber.
ESU: Electrostatic Unit.
Excitation: The addition of energy to a system, thereby transferring it from its ground state to an excited state. Excitation of a nucleus, an atom, or a molecule can result from absorption of photons or from inelastic collisions with other particles.
Exposure: Either (1) being exposed to ionizing radiation, or (2)A measure of the ionization produced in air by X or gamma radiation. It is the sum of the electrical charges on all ions of one sign produced in air when all electrons liberated by photons in a volume element of air are completely stopped in air, divided by the mass of the air in the volume element. The special unit of exposure is the roentgen.
Exposure Rate: The exposure per unit time (i.e.: Roentgen per hour)
External Dose: The portion of the Dose Equivalent received from exposure from any source outside the body.
External Radiation: Radiation from a source outside the body. The radiation must penetrate the skin.
Extremity: Hand, elbow, arm below the elbow, foot, knee, and leg below the knee.
Eye Dose Equivalent: The external dose equivalent to the lens of the eye at a tissue depth of 0.3 centimeters.
F
Film Badge: A pack of photographic film which measures radiation exposure for personnel monitoring. The badge may contain two or three films of differing sensitivity and filters to shield parts of the film from certain types of radiation.
Fixed Contamination: Radioactive contamination that is not removable
Flammable Solvent: An organic liquid whose vapor can form an ignitable mixture with air.
G
Gamma Ray: High energy, short wavelength electromagnetic radiation (range of energy from 10 keV to 9 MeV) emitted from the nucleus.
Geiger‑Mueller Counter: Highly sensitive, gas‑filled radiation ‑measuring device. It operates at voltages sufficiently high to produce avalanche ionization.
Genetic Effect: An effect in a descendant resulting from the modification of genetic material in a parent.
Geometry Factor: The fraction of the total solid angle about the source of radiation that is subtended by the face of the sensitive volume of a detector.
H
Halflife, Biological: The time required for the body to eliminate by natural processes, half the amount of a substance which has entered it.
Halflife, Effective: Time required for a radioactive element in an animal body to be diminished 50 percent as a result of the combined action of radioactive decay and biological elimination.
Effective half‑life = Biological half‑life X Radioactive half‑life
Biological half‑life + Radioactive half‑life
Halflife, Radioactive: Time required for a radioactive substance to lose 50 percent of its activity by decay. Each radionuclide has a unique half‑life.
Half Value Layer (Half Thickness) (HVL): The thickness of a specified substance which, when introduced into the path of a given beam of radiation, reduced the exposure rate by one‑half.
Health Physics (Physicist): A science and profession concerned with recognition, evaluation and control of health hazards from ionizing and non-ionizing radiation..
High Radiation Area: Any area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 0.1 rem in 1 hour at 30 centimeters from any source or radiation or from any surface which the radiation penetrates.
I
ICRP: International Commission of Radiological Protection. Under the auspices of the International Congress of Radiology, the commission prepares recommendations to deal with the basic principles of radiation protection.
Interlock: A device, usually electrical and/or mechanical, which prevents operation of a control until a preliminary condition has been met. Its purpose is usually safety.
Internal Dose: The portion of the dose equivalent received from radioactive materials taken into the body.
Internal Radiation: Radiation from a source within the body (as a result of deposition of radionuclides in body tissue.)
Inventory: A quantity of radioactive material on hand including stock and waste.
Ion: Atomic particle, atom, or chemical radical bearing an electrical charge, either negative or positive.
Ionization: The process by which a neutral atom or molecule acquires a positive or negative charge.
lonizing Radiation: Any radiation capable of displacing electrons from atoms, thereby producing ions (i.e. alpha, beta, gamma, x-rays)
Irradiation: Exposure to radiation.
Isotopes: Atoms having the same number of protons but different number of neutrons in their nuclei (i.e. the same atomic number but different mass number). Isotopes generally have almost identical chemical properties, but often different physical properties.
K
Kilo Electron Volt (keV): One thousand electron volts, 10E+3 eV.
Kilovolt Peak (kVp): The crest value in kilovolts of the potential difference of a pulsating potential generator. When only half the wave is used, the value refers to the useful half of the cycle.
L
Labeled Compound: A compound consisting, in part, of labeled molecules. By observations of radioactivity or isotopic composition, this compound or its fragments may be followed through physical, chemical, or biological processes.
Labeled Molecule: A molecule containing one or more atoms distinguished by non-natural isotopic composition (with radioactive or stable isotopes).
Laser: Light amplification by stimulated emission of radiation. The laser region is that portion of the spectrum which includes ultra‑violet, visible light and infrared.
Leakage Radiation: All radiation coming from within the source or tube housing, except the useful beam.
Liquid Scintillation Counter (LSC): A scintillation counter in which a sample of radioactive material is placed in a solution containing a phosphor. It is especially useful in the detection of low energy radiation.
Liquid Scintillation Fluid/Cocktail: A solution of a fluorescent substance dissolved in toluene or other suitable solvent. Radioactive material is added directly to the solution or cocktail for detection in a liquid scintillation counter.
M
Mass Defect: Difference between the mass of the nucleus as a whole and the sum of the component nucleon masses.
Mass Numbers: The number of nucleons (protons and neutrons) in the nucleus of an atom. (Symbol: A.)
Mega Electron Volt (MeV): One million electron volt, 10E+6 eV.
Member of the Public: Any individual, except an individual who is performing assigned involving exposure to radiation.
Microwave: An electromagnetic wave having a wavelength of approximately 1 meter to 1 millimeter corresponding to frequencies of about 300 to 300,000 megacycles per second.
Milliroentgen (mR): A submultiple of the roentgen, equal to one one‑thousandth of a roentgen. (See Roentgen.)
Minor: An individual less than 18 years of age
Monitoring: Periodic or continuous determination of the amount of ionizing radiation or radioactive contamination present in an occupied region.
Monitoring, Area: Routine monitoring of the radiation level or contamination of a particular area, building, room, or equipment. Some laboratories or operations distinguish between routine monitoring and survey activities.
Monoenergetic Radiation: Radiation of a given type (alpha, beta, neutron, gamma, etc.) in which all particles or photons originate with and have the same energy.
N
Neutron: An uncharged elementary particle found in the nucleus of every atom heavier than hydrogen.
NCRP: National Council on Radiation Protection and Measurements. A nonprofit corporation chartered by Congress to provide the public with information and recommendations concerning radiation and radiation protection.
Nuclide: a general term referring to all known isotopes, both stable and unstable, of the chemical elements.
Non-Stochastic Effects: A health effect , the severity of which varies with the dose and for which a threshold is believed to exist (i.e.: radiation induced cataracts, radiation burns).
NYSDOH: New York State Department of Health
O
Occupational Dose: The dose received by an individual in the course of employment in which the individual’s assigned duties involve exposure to sources of radiation. This dose not include doses received: from background radiation, as a patient from medical practices, from voluntary participation in medical research programs, of as a member of the public.
P
Pair Production: An absorption process for X and gamma radiation in which the incident photon is annihilated in the vicinity of the nucleus of the absorbing atom, with subsequent production of an electron and positron pair. This reaction only occurs for incident photon energies exceeding 1.02 MeV.
Parent: A radionuclide which, upon disintegration, yields a specific nuclide either directly or as a later member of a radioactive series.
Permissible Dose : The dose of radiation which may be received by an individual within a specified period with expectation of no significantly harmful result.
Personal Monitoring: Monitoring any part of an individual, his breath, or excretions, or any part of his clothing.
Photon: A quantum (or packet) of energy emitted in the form of electromagnetic radiation (i.e. gamma rays, x-rays).
Protective Clothing: Items worn by an individual to minimize the spread of contamination or shield the individual from external radiation (ex. plastic gloves, lab coat, lead apron, face shield).
Public Dose: The dose received by a member of the public from exposure to sources of radiation. It dose not include occupational dose, or doses received: from background radiation, as a patient from medical practices or from voluntary participation in medical research projects.
Q
Quality Control (QC): Periodic surveys or testing performed to ensure proper performance of a piece of equipment.
Quality Factor (QF): Modifying factor used to derive dose equivalent from absorbed dose.
R
Rad: The unit of absorbed dose equal to 0.01 J/kg in any medium. (See Absorbed Dose.) (Written: rad)
Radiation: The emission and propagation of energy through space or through a material medium in the form of waves or particles. The term radiation or radiant energy, when unqualified, usually refers to electromagnetic radiation which is commonly is classified, according to frequency (i.e. infrared, visible, ultraviolet, x‑ray, and gamma ray).
Radiation Area: An area in which an individual could receive s doe equivalent of 5 mrems in 1 hour at 30 centimeters from any source of radiation of from any surface which the radiation penetrates.
Radiation-Producing Equipment: Any equipment or device which can emit ionizing radiation by virtue of the application thereto of high voltage (ex: x‑ray machines, x‑ray diffractometers, fluoroscopes, electron microscopes).
Radiation Equipment Supervisor (RES): An individual authorized by the Radiation Safety Committee to direct and control the use of radiation equipment.
Radiation Safety Committee(RSC): A committee appointed by the University as the administrative body responsible for the safe use of radiation at Syracuse University.
Radiation Worker: An individual who has received the required training necessary to work with radiation and is authorized to do so by the RSO. These individuals must work under the direct supervision of a RES or RMS.
Radioactive Material: any solid, liquid, or gas which emits radiation spontaneously.
Radioactive Materials License: A license issued by New York State to an individual or an organization for the use of radioactive materials pursuant to Part 16 of the New York State Sanitary.
Radioactive Material Supervisor (RMS): An individual authorized by the Radiation Safety Committee to direct and control the use of radiation material under his possession.
Radioactivity: The transformation of unstable atomic nuclei by the emission of radiation.
Radiological Health: The art and science of protecting human beings from injury by radiation, and promoting better health through beneficial applications of radiation.
Rem: A special unit of dose equivalent. The dose equivalent in rems is numerically equal to the absorbed dose in rads multiplied by the quality factor, the distribution factor, and any other necessary modifying factors
Removable Contamination: Radioactive contamination that is found to be removable (detectable on a wipe test) from the contaminated surface.
Removable Contamination Survey: A procedure to determine the level of radioactive contamination on the surface of an object through the use of wipe tests.
Resolving Time: The minimum time interval between two distinct events which will permit both to be counted. It may refer to an electronic circuit, to a mechanical indicating device, or to a counter tube.
Respiratory Protective Equipment: An apparatus, such as a respirator, used to reduce an individual’s intake of airborne radioactive material.
Restricted Area: See “controlled area”
Roentgen (R): Unit of exposure. One Roentgen equals 2.58E-04 coulumbs/kilogram of air.
S
Scattering: Change of direction of subatomic particles or photons as a result of a collision or interaction.
Scattered Radiation: Radiation which during its passage through a substance, has been deviated in direction. It may also have been modified by a decrease in energy.
Scintillation Counter: The combination of phosphor, photomultiplier tube, and associate circuits which register coincidences caused by the type of events under consideration.
Sealed Source: A radioactive source sealed in an impervious container which has sufficient mechanical strength to prevent contact with and dispersion of the radioactive material under the conditions of use and wear for which it was designed.
Secondary Radiation: Radiation resulting from absorption of other radiation in matter. It may be either electromagnetic or particulate.
Shallow Dose Equivalent (Hs): The dose equivalent due to external Exposure of the skin of an extremity at a tissue depth of 0.007 centimeter average over an 1 square centimeter area.
Shielding: Any material or obstruction that absorbs radiation.
Specific Gamma‑Ray Constant: For a nuclide emitting gamma radiation, the product of exposure rate at a given distance from a point source of that nuclide and the square of that distance divided by the activity of the source, neglecting attenuation.
Standard, Radioactive: A sample of radioactive material, usually with a long half‑life, in which the number and type of radioactive atoms at a definite reference time is known. It may be used as a radiation source for calibrating radiation measurement equipment.
Stochastic Effect: A health effect that occurs randomly and for which the probability of the effect, rather that its severity, is assumed to be a function of the dose without threshold (i.e. hereditary effects, cancer).
Survey, Radiological: Evaluation of the radiation hazards incident to the production, use, or existence of radioactive materials or other sources of radiation under specific conditions.
Swipe Test: A survey technique for locating removable contamination on surfaces. The test involves wiping the surface with a damp absorbant material and then monitoring the level of radiation on the absorbant material.
T
Total Effective Dose Equivalent (TEDE): The sum of the deep dose equivalent for external exposures and the committed effective dose equivalent for internal exposures.
Tritium: The hydrogen isotope with one proton and two neutrons in the nucleus.
Tracer, Isotopic: The isotope or non‑natural mixture of isotopes of an element which may be incorporated into a sample to permit observation of the course of that element, alone or in combination, through a chemical, biological, or physical process. The observations may be made by measurement of radioactivity or of isotopic abundance.
V
Very High Radiation Area: An area, accessible to individuals, in which radiation levels could result in an individual receiving an absorbed dose of 500 rad in 1 hour at 1 meter from a source of radiation or from any surface that the radiation penetrates.
Volt: The unit of electromotive force (IV = IW/1A).
W
Wavelength: Distance between any two similar points of two consecutive waves (2) for electromagnetic radiation. The wavelength is equal to the velocity of light (c) divided by the frequency of the wave (v), ‑ c/v. The “effective wavelength” is the wavelength of a monochromatic x rays which would undergo the same percentage attenuation in a specified filter as the heterogeneous beam under consideration.
Weighting Factor WT: The proportion of the risk of stochastic effects resulting from irradiation of an organ/tissue (T) to the total risk of stochastic effects when the whole body is irradiated uniformly.
Wipe Test: See Swipe test
Whole Body: For the purpose of external exposure, it means head, trunk, male gonads, arm above elbow, leg above knee.
X
X‑Ray: Penetrating electromagnetic radiation whose wavelengths are shorter than those of visible light. They are usually produced by bombarding a metallic target with fast electrons in a high vacuum. In nuclear reactions, it is customary to refer to photons originating in the nucleus as gamma rays, and those originating in the extranuclear part of the atom as x rays. These rays are sometimes called roentgen rays after their discoverer, W.C. Roentgen.
Waste, Radioactive Material (or Radioactive): Solid, liquid or biological waste material containing radioactive material in excess of natural levels.