Glossary of Radiological Terminology (R)

GLOSSARY OF
RADIOLOGICAL TERMINOLOGY

RAD The unit of absorbed dose. One (1) rad is equal to an absorbed dose of 100 ergs/gram.
RADIATION The emission and propagation of energy through space or through a material medium in the form of waves; for instance, the emission and propagation of electromagnetic waves.
RADIATION AREA An area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 0.005 rem (0.05 mSv) in one hour or in any five (5) consecutive days, a dose in excess of 0.010 rem (0.10 mSv).
RADIATION SOURCE Usually a man made sealed source of radiation used in teletherapy, radiography, as a power source or used in various types of industrial gauges.
RADIATION WARNING An official symbol in magenta on a yellow background that must be displayed where certain quantities of radioactive materials are present or where certain doses of radiation could be received.
RADIATION WORKER An individual who uses radioactive materials under the licensee's control. Individuals must be trained and have passed a radiological health exam (RHE) prior to working with radioactive materials.
RADIOACTIVITY The property of certain nuclides of spontaneously emitting particles or gamma radiation or of emitting x radiation following orbital electron capture or of undergoing spontaneous fission.
RADIOGRAPHY The making of shadow images on photographic film by the action of ionizing radiation.
RADIOISOTOPE A nuclide with an unstable ratio of neutrons to protons placing the nucleus in a state of stress. In an attempt to reorganize to a more stable state, it may undergo various types of rearrangement that involve the release of radiation.
RADIOLOGY That branch of medicine dealing with the diagnostic and therapeutic applications of radiant energy, including x-rays and radioisotopes.
RADIOLOGICAL SURVEY The evaluation of the radiation hazards accompanying the production, useage, or existence of radioactive materials. Usually includes measurements or estimates of the levels of radiation and may require corrective actions.
RADIONUCLIDE A radioactive isotope of an element.
RADIOSENSITIVITY The relative susceptibility of cells, tissues, organs, organisms, or other substances to the injurious action of radiation.
RADON (Rn) A radioactive element that is one of the heaviest gases known.
RADIOTOXICITY The term referring to the potential of an isotope to cause damage to living tissue by absorption of energy from the disintegration of the radioactive material introduced into the body.
REFERENCE MAN A hypothetical aggregation of human physical and physiological characteristics arrived at by international consensus. These characteristics may be used by researchers and pulic health workers to standardize results of experiments and to relate biological insult to a common base.
RELATIVE BIOLOGICAL EFFECTIVENESS For a particular living organism or part of an organism, the ratio of the absorbed dose of a reference radiation that produces a specified biological effect to the absorbed dose of the radiation of interest that produces the same biological effect.
REM The unit of dose equivalent. The dose equivalent in rems is numerically equal to the absorbed dose in rads multiplied by the quality factor, distribution factor, and any other necessary modifying factors.
REMOVABLE CONTAMINATION Contamination deposited on the surface of structures, areas, objects or personnel that can readily be removed or wiped up by physical or mechanical means during the course of a survey or during decontamination efforts.
RESTRICTED AREA An area to which access is controlled for the protection of individuals from exposure to radiation and radioactive materials.
ROENTGEN (R) The quantity of x or gamma radiation such that the associated corpuscular emission per 0.001293 grams of dry air produces, in air, ions carrying one electrostatic unit of quantity of electricity of either sign. An amount of energy equal to 2.58 E-4 coulombs/ kg air. The Roentgen is a special unit of exposure and named after Wilhelm Roentgen, a German scientist who discovered x-rays in 1895.

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RAD	The unit of absorbed dose. One (1) rad is equal to an absorbed dose of 100 ergs/gram.
RADIATION	The emission and propagation of energy through space or through a material medium in the form of waves; for instance, the emission and propagation of electromagnetic waves.
RADIATION AREA	An area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 0.005 rem (0.05 mSv) in one hour or in any five (5) consecutive days, a dose in excess of 0.010 rem (0.10 mSv).
RADIATION SOURCE	Usually a man made sealed source of radiation used in teletherapy, radiography, as a power source or used in various types of industrial gauges.
RADIATION WARNING	An official symbol in magenta on a yellow background that must be displayed where certain quantities of radioactive materials are present or where certain doses of radiation could be received.
RADIATION WORKER	An individual who uses radioactive materials under the licensee's control. Individuals must be trained and have passed a radiological health exam (RHE) prior to working with radioactive materials.
RADIOACTIVITY	The property of certain nuclides of spontaneously emitting particles or gamma radiation or of emitting x radiation following orbital electron capture or of undergoing spontaneous fission.
RADIOGRAPHY	The making of shadow images on photographic film by the action of ionizing radiation.
RADIOISOTOPE	A nuclide with an unstable ratio of neutrons to protons placing the nucleus in a state of stress. In an attempt to reorganize to a more stable state, it may undergo various types of rearrangement that involve the release of radiation.
RADIOLOGY	That branch of medicine dealing with the diagnostic and therapeutic applications of radiant energy, including x-rays and radioisotopes.
RADIOLOGICAL SURVEY	The evaluation of the radiation hazards accompanying the production, useage, or existence of radioactive materials. Usually includes measurements or estimates of the levels of radiation and may require corrective actions.
RADIONUCLIDE	A radioactive isotope of an element.
RADIOSENSITIVITY	The relative susceptibility of cells, tissues, organs, organisms, or other substances to the injurious action of radiation.
RADON (Rn)	A radioactive element that is one of the heaviest gases known.
RADIOTOXICITY	The term referring to the potential of an isotope to cause damage to living tissue by absorption of energy from the disintegration of the radioactive material introduced into the body.
REFERENCE MAN	A hypothetical aggregation of human physical and physiological characteristics arrived at by international consensus. These characteristics may be used by researchers and pulic health workers to standardize results of experiments and to relate biological insult to a common base.
RELATIVE BIOLOGICAL EFFECTIVENESS	For a particular living organism or part of an organism, the ratio of the absorbed dose of a reference radiation that produces a specified biological effect to the absorbed dose of the radiation of interest that produces the same biological effect.
REM	The unit of dose equivalent. The dose equivalent in rems is numerically equal to the absorbed dose in rads multiplied by the quality factor, distribution factor, and any other necessary modifying factors.
REMOVABLE CONTAMINATION	Contamination deposited on the surface of structures, areas, objects or personnel that can readily be removed or wiped up by physical or mechanical means during the course of a survey or during decontamination efforts.
RESTRICTED AREA	An area to which access is controlled for the protection of individuals from exposure to radiation and radioactive materials.
ROENTGEN (R)	The quantity of x or gamma radiation such that the associated corpuscular emission per 0.001293 grams of dry air produces, in air, ions carrying one electrostatic unit of quantity of electricity of either sign. An amount of energy equal to 2.58 E-4 coulombs/ kg air. The Roentgen is a special unit of exposure and named after Wilhelm Roentgen, a German scientist who discovered x-rays in 1895.