RadNet
RadNet Glossary
A
alpha particle
A positively charged particle made up of two neutrons and two protons emitted by certain radioactive nuclei. Alpha particles can be stopped by thin layers of light materials, such as a sheet of paper or the dead cells in the outer skin layer. They are not an external health threat to the body. However, they can pose a serious health threat if ingested (swallowed) or inhaled.
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- Related Terms
neutrons | pathways | protons - Alpha Particles
This information describes the make up of alpha particles and their behavior.
ambient air
The air that surrounds us.
B
background (radiation)
Natural radiation caused by sun exposure, cosmic rays from space, and radioactive elements found in the earth's crust. Radon, a radioactive gas that seeps from the ground, is an example of natural radiation. Cosmic rays include energetic protons, electrons, gamma rays, and x-rays. The primary radioactive elements found in the earth's crust are uranium, thorium, and potassium, and the radionuclides produced as they radioactively decay.
baseline
The radionuclide concentration or radiation level that is considered "normal" under routine conditions. A baseline is usually determined by averaging many measurements of background radiation. Comparing a sample's analysis results to the baseline will show if radiation levels are normal or high.
beta particles
An electron or positron emitted by certain radioactive nuclei. Beta particles can be stopped by aluminum. They can be a serious direct or external radiation threat to the body and can be lethal depending on the amount received. They also pose a serious internal radiation threat if inhaled or ingested (swallowed).
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direct or external pathway - Beta Particles
This fact sheet offers basic information about the origin and behavior of these particles.
C
Curie (Ci)
A measure of radioactivity based on the radioactive decay rate of approximately one gram of radium. The Curie was named in honor of Pierre and Marie Curie, pioneers in the study of radiation.
One Curie of any radionuclide has 37 billion disintegrations (transformations) in one second.
| Units | |||||
|---|---|---|---|---|---|
| Factor | Prefix | Symbols | Factor | Prefix | Symbols |
| 1018 | exa | E | 10-1 | deci | d |
| 1015 | peta | P | 10-2 | centi | c |
| 1012 | tera | T | 10-3 | milli | m |
| 109 | giga | G | 10-6 | micro | |
| 106 | mega | M | 10-9 | nano | n |
| 103 | kilo | k | 10-12 | pico | p |
| 102 | hecto | h | 10-15 | femto | f |
| 101 | deka | da | 10-18 | atto | a |
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- Marie and Pierre Curie
This page describes the work of the Curies.
D
deployable
In the RadNet system, portable monitors that can be sent (deployed) quickly to a location where they are needed
dose
The amount of radiation or energy absorbed. There are different ways to measure dose:
- absorbed dose, the amount of energy deposited per unit mass
- equivalent dose, a way to measure dose that accounts for the fact that different radionuclides can have more or less affect on the body (called "relative biological effect").
- committed dose, a dose that accounts for continuing exposures over long periods of time (such as 30, 50, or 70 years).
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- Health Effects
This information explains the effects of radiation on human health. - Radiation Protection Basics
This information describes the factors that can reduce exposure.
E
exposure
A term relating to the amount of ionizing radiation that strikes a surface. (This is a general definition. In health physics, exposure is specifically defined as a measure of ionization in air caused by x-ray or gamma radiation only.)
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- Exposure Pathways
This information describes the ways that people may be exposed to radiation.
FGHI
fission
The splitting of a nucleus of an atom into at least two other nuclei that releases a relatively large amount of energy. Two or three neutrons are usually released during this type of transformation.
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neutrons
gamma rays
Electromagnetic radiation that has high energy and a short wavelength. All gamma rays emitted from a given isotope have the same energy, a characteristic that enables scientists to identify which gamma emitters are present in a sample. Gamma rays are very similar to x-rays. They can be a serious direct or external radiation threat to the body and can be lethal depending on the amount received.
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direct or external pathways | x-rays - Gamma Rays
This information explains the makeup of gamma rays and their behavior.
half-life
the time required for one half the atoms of a given amount of a radioactive substance to disintegrate (radioactively decay).
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- Half-Life
This information explains and illustrates radioactive half-life.
health physicist
A scientist who focuses on radiation protection of humans and the environment. Health Physics uses physics, biology, chemistry, statistics and special instruments such as Geiger counters to help protect individuals from any damaging effects of radiation.
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- Health
Physics Society:Public and Media Information
This Web site describes the activities of the organization, provides access to their ask the experts (radiation safety), fact sheets and a list of radiation definitions.
- Careers in Radiation: Health Physicist
This link provides a description and explains the origin of health physicist.
ionizing radiation
Radiation from naturally occurring and man-made radionuclides, including alpha and beta particles and gamma rays. Ionizing radiation has enough energy to break chemical bonds.
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radionuclides
isotope
A nuclide of an element having the same number of protons but a different number of neutrons.
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- Nuclides and Isotopes
This information explains the differences and similarities between nuclides and isotopes.
JKLM
maximum contaminant level (MCL)
limits on the levels of contaminants in public drinking water systems. MCLs are "primary drinking water standards. National Primary Drinking Water Regulations (NPDWRs or primary standards) are legally enforceable standards that apply to public water systems. Primary standards protect public health by limiting the levels of contaminants in drinking water.
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- Read more about Maximum Contaminant Levels
monitoring
The use of sampling and detection equipment to measure the levels of radiation or other materials in soil, air, or water.
N
neutron
A small particle possessing no electrical charge and typically found inside an atom's nucleus. A neutron has about the same mass as a proton.
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nucleus | proton - What is an Atom?
The information describes the makeup and behavior of atoms.
nuclear energy
The heat energy produced by the process of nuclear reaction (fission or fusion) within a nuclear reactor or by radioactive decay.
nuclear fallout
Radioactive particles that fall to the ground after a nuclear explosion.
nucleus
the positively charged mass >at the center of an atom, composed of neutrons and protons
OP
particulates
Minute separate particles of material such as dust that are usually captured with filters from samples of air or water.
pathways
The ways in which people are exposed to radiation or other contaminants. The three basic pathways are inhalation (contaminants are taken into the lungs), ingestion (contaminants are swallowed), and direct (external) exposure (contaminants cause damage from outside the body).
picocurie (pCi)
One one-trillionth (1/1,000,000,000,000) of a curie.
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curie
plume
an area of contamination as it spreads into the environment from the source of the contamination
proportional counter
A radiation detector that produces a signal which is proportional to the radiation energy that strikes it.
proton
A small particle in an atom's nucleus, that has a positive electrical charge. Each chemical element has a particular number of protons. When an atom loses a proton during radioactive decay, it becomes an atom of a different element.
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- Related Terms
radioactive decay
QRST
quality assurance (QA)
A set of activities such as testing and assessment that ensure high quality in a product
radioactive decay
The spontaneous disintegration of the nucleus of an unstable atom that produces ionizing radiation, including alpha or beta particles and gamma rays
radiological
Involving radioactive material
radionuclides
"Versions" of chemical elements that are not stable, or in other words, are likely to radioactively decay, giving off ionizing radiation
More Info
- Radionuclide fact sheets
These fact sheets provide basic information about the discovery and properties of several radionuclides.
risk
The probability of injury or harm under specific circumstances. Risk can be expressed as a value that ranges from zero (no injury or harm will occur) to one hundred percent (harm or injury will definitely occur). Risk-based standards limit the risk that a release of a contaminant to the environment may pose rather than limiting the quantity that may be released.
spectrographic analysis
Gamma-ray spectroscopy is a technique used to identify the identities and quantities of gamma-ray-emitting radionuclides in a sample. This process uses special detectors and computer software to analyze the range (spectrum) of energies the sample emits.
UVWXYZ
x-rays
High-energy electromagnetic radiation that has high energy and a short wave length. X-rays are very similar to gamma rays.
yield
the explosive force of a nuclear bomb. It is given in terms of the amount of TNT that would release the same amount of energy.