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53 Cards in this Set
- Front
- Back
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Atom |
Is the smallest particle of an element that still retains the properties of the element |
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Background Radiation |
Ionizing radiation that is always present in our environment. Such as: 1. Cosmic radiation from outer space
2. Terrestrial radiation from the earth and its environments (Radon Gas)
3. Naturally occurring radionuclides that are deposited in our bodies by inhalation and ingeston. |
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Beta Particle |
A form of particulate radiation/ High speed negative electrons |
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Coherent Scattering |
Radiation that is scattered when a low- energy x-ray passes near an atoms' outer electron.
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How much of the of the interactions of matter with the dental x-ray beam are the result of coherent scattering? |
8% |
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Compton Effect (scattering) |
Only a part of the dental x-ray energy is transferred to the electron, and a new weaker x-ray is formed and scattered in some new direction opposite of the original x-ray. |
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Photoelectric effect |
all or nothing energy loss
the x-ray imparts all its energy to an orbital electron of some atom
All of the energy from the photon is absorbed by the displaced electron in the form of Kinetic energy |
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Decay |
Is unstable isotopes that are radioactive and attempt to regain stability through the release of energy |
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Electrons have what kind of charge and are constantly doing what around the nucleus? |
Has a Negative Charge and constantly in motion orbiting the nucleus |
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Protons have what kind of charge and determines what? |
Has a positive charge
The number of protons in a nucleus of an element determines its atomic number |
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Neutrons have what kind of charge |
Have no Charge |
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What is Ionization |
is the formation of ion pairs |
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What is an ion |
are atoms that have lost or gained an electron
Defined as a charged particle |
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A positive ion |
Has more protons than electrons |
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What is it called when atoms have gained or lost an electron and are electrically unstable? |
an ION |
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TRUE or FALSE When an atom is struck by an x-ray photon, an electron may be dislodged and an ion pair is created.
As high- energy electrons travel on, they push out electrons from the orbits of other atoms. Creating additional ion pairs
These unstable ions attempt to regain electrical stability by combining with opposite charged ions |
All 3 statements are true |
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Radiation |
the emission and movement of energy through space in the form of electromagnetic radiation of particulate radiation. |
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Radioactivity
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is the process where by certain unstable elements undergo spontaneous disintegration in an effort to attain a stable nuclear state.
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Do Dental x-rays use radioactivity? |
NO |
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Electromagnetic Radiation |
is the movement of wavelike energy through space as a combination of electric and magnetic fields. |
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What properties does the electromagnetic spectrum have? (6) |
1. travel at the speed of light
2. Have no electrical charge
3. Have no mass or weight
4. Have energies that are measurable and different
5. Pass through space as particles and in a wavelike motion
6. Give off an electric field to= right angles of their path of travel and
a magnetic field to= right angles to the electric field |
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Photons |
Bundles of energy that travel through space at the speed of light |
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Wavelength definition ?
Whats it measured in?
does it have a direct or indirect relationship to radiation? |
Is the distance between two similar points on two successive waves.
Measured in Angstrom
INDIRECT- The shorter the wavelength the more penetrating the radiation.
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Frequency definition?
Whats it measured in?
Does it have a direct or indirect relationship to radiation? |
Is a measure of the number of waves that pass a given point per unit of time.
Measured in Hertz
DIRECT- The higher the frequency, the more penetrating the radiation.
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Velocity definition |
Speed of a wave
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Which kind of radiation has limited penetrating power and are unsuitable for exposing dental radiographs |
Soft radiation |
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What kind of radiation has great penetrating power |
Hard radiation |
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What is the relationship between wavelength and frequency? |
INDIRECT-
Long wavelength= low frequency, low energy (Less penetrating)
Short wavelength= high frequency, high energy (more penetrating) |
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What are the properties of x-rays? (9) |
1. Invisible
2. Travel in straight lines
3. Travel at the speed of light
4. Have no mass or weight
5. No charge
6. Interact with matter causing ionization
7. can penetrate opaque tissues and structures
8. can affect photographic film emulsion (causing a latent image)
9. can affect biological tissue |
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Radiopaque looks like what on a radiograph |
white or light gray on the radiograph
Bone and Enamel
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Materials that are extremely dense and have high atomic weight will absorb more or less x-rays than materials that are thin with low atomic weight. |
MORE x-rays are absorbed |
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Radiolucent - |
Appears dark gray or black
pulp chambers, muscles and skin |
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General/ Bremsstrahlung Radiation is produced when? |
high speed electrons are stopped or slowed down by the tungsten atoms of the dental x-ray tube |
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Characteristic Radiation is produced when? |
bombarding electron from the tube filament collides with an orbiting K electron of the tungsten target.
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At what kVp does an x-ray machine have to be at to produce characteristic radiation. |
70 or above kVp
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What are the 4 possible interactions of dental x-rays with matter? |
No Interaction Coherent scattering photoelectric effect Compton effect |
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No Interaction of dental x-rays with matter means what? |
the x-ray can pass through an atom unchanged and no interaction occurs |
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Coherent Scattering of dental x-rays with matter means what? |
(Unmodified scattering)
When a low energy x-ray passes near an atoms outer electron, it may be scattered without any loss of energy
Scattered= no loss of energy |
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Photoelectric effect of dental x-rays with matter means what? |
This is an all or nothing energy loss
the dental x-ray simply vanishes because it was only made of energy
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Compton Effect of dental x-rays with matter means what? |
Only part of the dental x-ray energy is transferred to the electron and a new, weaker x-ray is formed and scattered in a new direction
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Compton's effect accounts for what percent of interactions of matter with the dental x-ray beam? |
60% |
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The most widely accepted terms used for radiation units of measurements come from where? |
systeme internationale (SI) |
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What are the systeme internationale units? |
Columbus per kilogram (C/kg) Gray (Gy) Sievert (Sv) |
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What is the unit of measuring exposure? |
Columbus per kilogram (C/kg) |
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What is the unit of measuring the absorbed dose? |
Gray (Gy) |
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What is the unit of measuring dose equivalent? |
Sievert (Sv) |
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the measurement of ionization in air produced by x or gamma rays is known as what? |
Is Exposure |
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The amount of energy deposited in any form of matter (By any type of radiation) |
Absorbed Dose |
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Product of the absorbed dose X a biological effect qualifying or weighting factor is known as? |
Dose equivalent |
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To aid in making more accurate comparisons between different radiographic exposures. Is used to compare the risk of the radiation exposure producing a biological response is known as what? |
Effective Dose Equivalent |
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What are the 3 basic building bocks of an atom? |
Protons, neutrons, and electrons |
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Ionizing radiation is what? |
any radiation that produces ions
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Electromagnetic radiation has what properties of what? |
Wavelength
frequency
velocity |
