Radioactive Materials Branch
General Definitions used in Health Physics & Radiation Protection

M

Medical Use
The intentional internal or external administration of radioactive material or the radiation therefrom to patients or human research subjects under the supervision of an authorized user.

Mega-
A prefix that multiplies a basic unit by 1,000,000.

Member of the public
Any individual except when that individual is receiving an occupational dose.

Micro-
A prefix that divides a basic unit into one million parts (i.e., 1/1,000,000).

Milli-
A prefix that divides a basic unit by 1,000 (i.e., 1/1000).

Mineral Logging
Logging performed for the purpose of mineral exploration other than oil or gas.

Minor
An individual less than 18 years of age.

Misadministration
Means the administration of the following:

Mobile nuclear medicine service
Means the transportation and medical use of radioactive material.

Molecule
A group of atoms held together by chemical forces. A molecule is the smallest unit of a compound that can exist by itself and retain all of its chemical properties.

Monitoring ("radiation monitoring" or "radiation protection monitoring")
The measurement of radiation levels, concentrations, surface area concentrations or quantities of radioactive material and the use of the results of these measurements to evaluate potential exposures and doses.

N

Nano-
A prefix that divides a basic unit by one billion (i.e., 1/1,000,000,000).

Natural radioactivity
Radioactivity of naturally occurring nuclides.

Negative pressure respirator
A tight-fitting respirator in which the air pressure inside the facepiece is negative during inhalation with respect to the ambient air pressure outside of the respirator.

Neutrino
A electrically neutral particle of very small (probably zero) rest mass and of spin quantum number  ½.  Postulated by Pauli in explaining the beta decay process.   Neutrinos and antineutrinos can penetrate amounts of matter measured in light years without appreciable attenuation.

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.

Noble Gas
A gaseous chemical element that does not readily enter into chemical combination with other elements. An inert gas.

NORM
An acronym for Naturally Occurring Radioactive Material

Nonstochastic effect
Health effects, the severity of which varies with the dose and for which a threshold is believed to exist. Radiation-induced cataract formation is an example of a nonstochastic effect (also called a deterministic effect).

NRC
United States Nuclear Regulatory Commission or its duly authorized representatives.

Nucleus; nuclei (plural)
The small, central positively charged region of an atom that carries essentially all the mass. Except for the nucleus of ordinary (light) hydrogen, which has a single proton, all atomic nuclei contain both protons and neutrons. The number of protons determines the total positive charge, or atomic number. This is the same for all the atomic nuclei of a given chemical element. The total number of neutrons and protons is called the mass number.

Nuclide
A general term referring to all known isotopes, both stable (279) and unstable (about 5,000), of the chemical elements.

O

Occupational dose
The dose received by an individual in the course of employment in which the individual's assigned duties involve exposure to radiation or radioactive material from licensed and unlicensed sources of radiation, whether in the possession of the licensee or registrant or other person. Occupational dose does not include dose received from background radiation, as a patient from medical practices, from exposure to individuals administered radioactive material and released in accordance with 15A NCAC 11 .0358 of this Chapter, from voluntary participation in medical research programs, or as a member of the general public.

P

Parent
A radionuclide that upon radioactive decay or disintegration yields a specific nuclide (the daughter).

Particle accelerator
Any machine capable of accelerating electrons, protons, deuterons, or other charged particles.

Periodic Table
An arrangement of chemical elements in order of increasing atomic number. Elements of similar properties are placed one under the other, yielding groups or families of elements. Within each group, there is a variation of chemical and physical properties, but in general, there is a similarity of chemical behavior within each group.

Person
Any individual, corporation, partnership, firm, association, trust, estate, public or private institution, group, agency, political subdivision of this state, any other state or political subdivision or agency thereof, and any legal successor, representative, agent or agency of these entities.

Periodic training
A periodic review conducted or provided by the licensee or registrant for its employees on radiation safety aspects of radiography. The review shall include the results of internal inspections, new procedures or equipment, accidents or errors that have been observed, and opportunities for employees to ask safety questions.

Permanent radiographic installation
An enclosed shielded room, cell, or vault in which radiography is performed.

Personnel monitoring equipment
Devices, such as film badges, pocket dosimeters, and thermoluminescent dosimeters, designed to be worn or carried by an individual for the purpose of estimating the dose received by the individual.

Pharmacist
An individual licensed by this state to compound and dispense drugs, prescriptions and poisons.

Physician
An individual currently licensed to practice medicine in this state.

Pico-
A prefix that divides a basic unit by one trillion (i.e., 1/1,000,000,000,000).

Planned special exposure
An infrequent exposure to radiation, separate from and in addition to the annual dose limits.

Positive pressure respirator
A respirator in which the pressure inside the respiratory inlet covering exceeds the ambient air pressure outside the respirator.

Positron
A particle with the same mass as an ordinary electron.  It has a positive electrical charge of exactly the same amount as an electron.  Positrons are created either by radioactive decay of certain unstable nuclei, or in collisions between photons of greater than 1 MeV and electrically charged particles or photons.  A positron does not decay, but rather will collide with an ordinary electron and in this collision, the positron-electron pair is annihilated.  This results in the coincident emission of two photons, each with an energy of 0.511 MeV.  These photons are are emitted 180º apart, making spatial localization possible.

Powered air-purifying respirator (PAPR)
An air-purifying respirator that uses a blower to force the ambient air through air-purifying elements to the inlet covering.

Prescribed dosage
The quantity of radiopharmaceutical activity documented in a written directive by an authorized user.

Prescribed dose means:

Pressure demand respirator
A positive pressure atmosphere-supplying respirator that admits breathing air to the facepiece when the positive pressure is reduced inside the facepiece by inhalation.

Projection sheath
A flexible or rigid tube for guiding the source assembly and the attached control cable from the exposure device to the exposure head. When the source assembly is fully extended to the exposure head, the sealed source is in what is commonly called the working position.  Commonly called a guide tube or "J" tube.

Proton
An elementary nuclear particle with a positive electric charge and a mass slightly less than that of a neutron but about 1836 times greater than that of an electron,   located in the nucleus of an atom.

Public dose
The dose received by a member of the public from exposure to radiation or radioactive material released by a licensee or registrant, or to another source of radiation within a licensee's or registrant's control. It does not include occupational dose or doses received from background radiation, as a patient from medical practices, from exposure to individuals administered radioactive material and released in accordance with Rule .0358 of this Chapter, or from voluntary participation in medical research programs.