Term
| Uses of Dental Radiographs |
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Definition
To detect lesions, disease, and conditions of the teeth and surrounding structures.
To confirm suspected disease
To Localize lesions or foriegn objects
To provide information during dental procedures
To evaluate growth and development
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| An atom that gains or loses an electron and becomes electrically unbalanced |
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| The production of ions or the process of converting an atom into ions. |
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| The atom as a positive ion and the ejected electron as a negative ion. This ion pair reacts with other ions until electrically stable, neitral atoms are formed |
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| The emission and propagation of energy through space and time or a substance in the form of waves or particles. |
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| Not the same thing as radiation. Process by which certain unstable atoms or elements undergo spontaneous decay. In an effort to attain a more balanced state |
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| Tiny particles of matter that posses mass and travel in straight lines and at high speeds |
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| Electromagnetic radiation |
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Definition
| The propogation of wavelike energy (without mass) through space or matter |
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Term
Electromagnetic Radiation
Particle Concept: |
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Definition
| discrete bundles of energy called photons that have no mass or weight and travel as waves at the speed of light and move through space in a straight line carrying energy of electromagnetic radiation. |
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Electromagnetic Radiation
Wave Concept: |
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Definition
Characterizes electromagnetic radiation as waves
Velocity: speed of waves
Wave length: Distance between the crest of each wave
Frequency: The number of wavelengths that pass a given point in a certain amount of time. |
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| high energy electromagnetic ionizing radiation |
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| Negative electrode when heated produces neg electrons through a tungston filament then they are gathered on the molybdenum cup which focuses the electrons in a narrow beam accross the tube to the anode. |
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Definition
turns electrons into xray photons creates cloud.
tungston plate is focal spot for the electrons coming from cathode. Copper stem of the tungston plate is there to dissapate heat. |
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Definition
| electrons flowing in one direction |
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| electrons flow in 2 opposite directions |
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| conversion from alternating current to direct current |
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| # of electrons moving through a conductor. current measured in amperes or milliamperes |
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| measurement of electrical force that causes electrons to move from a neg pole to positive. |
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| circuit that regulates how much electrons are producedb controlled by MA |
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| high voltage to accelerate electrons controlled by kv |
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| decreases volts from 110-220 to 3-5 volts for filament circuit |
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Definition
| increases incoming voltage to 65k for use of high voltage circuit |
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Definition
| serves as a voltage compensator and corrects minor flucctuation int he current |
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| 70% of x ray energy produced (braking radiation) stopping of radiation reflects as gets close to nucleus |
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Definition
| a small part of xrays produced. xray dislodges inner shell and the electrons ionize. |
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Interaction of radiation
3 possibilities |
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Definition
1. Pass through patient with no interaction (image production)
2. Photons can be completely absorbed - photoelectric effect
3. photons can be scattered
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Term
| Scattered photons 2 different ways |
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Definition
compton scatter
1. causes ionization and accounts for 62% of scatter
Coherent Scatter:
remains the same. just has change in direction
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Term
primary radiation
second radiation -scatter radiation |
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Definition
xray beam produced at the target
beam created when primary radiation strikes matter - creates scatter radiation
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Definition
| penetrating ability of the xray beam. Controlled by Kvp |
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Definition
| overall blackness of a film |
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Definition
how sharply dark and light areas are differentiated or seperated on film
Low kvp = high contrast - caries
High KVP = Low contrast - periodontal and periapical disease |
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Definition
kvp is increased by 15 exposure time decreased by 1/2
Kvp is decreased by 15, exposure time should be doubled |
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| #of electrons or current flowing through the cathode filament |
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regulates temp therefore controls amount of electrons produced. 7-15 ma
Increased MA = decreased exposure time for patient who cant sit still
Increased MA = more dense on radiograph |
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| pretty much states that going from 8 inch PID to 16 inch PID = 1/4 less intensity |
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Aluminum filter
HVL (high value LAyer) |
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Definition
placed in path of beam to reduce intensity
The thickness of aluminum placed in path of xray beam reduces it by half |
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Definition
1974
Fed - regulated manufacture
state - reg how used and codes |
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Intensifying screen
Calcium tungstate screens
Rare earth screen |
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Definition
have phosphors that emit blue light
phosphors emit green light - more efficient - less exposure - faster
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