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43 Cards in this Set
- Front
- Back
Attenuation
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process by which a beam of radiation is reduced in energy when passing through tissue or other materials
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Central Ray
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theoretical center of a beam of radiation
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Contrast
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difference between adjacent densities on a radiograph
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Density
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degree of darkening of exposed and processed photographic or radiographic film
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Distortion
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misrepresentation of the true size or shape of an object
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Dynamic
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with motion
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Fog
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unwanted exposure or film densities
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Grid
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device consisting of thin lead strips designed to permit primary radiation to pass while reducing scatter radiation
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Half-Value Layer
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amount of filtration necessary to reduce the intensity of the radiation beam to one half its original value
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Image Receptor
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medium used to capture the image for recording, such as x-ray film or a digital imaging plate
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Intensifying Screen
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layer of luminescent crystals placed inside a cassette to expose x-ray film efficiently and thereby significantly reduce patient dose
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Inverse Square Law
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mathematical formula that describes the relationship between radiation intensity and distance from the source of the radiation
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Kilovoltage Peak (kVp)
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measure of the potential difference, which controls the quality and quantity of x-ray photons produced in the x-ray tube
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Latent Image
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invisible image created after exposure but before processing
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Milliampere Seconds (mAs)
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measurement of milliamperage times seconds, which controls the quantity of x-ray photons produced in the x-ray tube
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Penetrating Ability
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ability of an x-ray beam to pass through an object, controlled by the kVp of the beam
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Penumbra
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fuzzy border of an object as imaged radiographically
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Photon
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quantum or particle of radiant energy
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Positive Beam Limitation (PBL)
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automatic collimation system used on diagnostic x-ray units
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Primary Radiation
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x-ray beam after it leaves the x-ray tube and before it reaches the object
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Radiolucent
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permitting the passage of x-rays or other forms of energy with little attenuation
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Radiopaque
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not easily penetrable by x-rays or other forms of radiant energy
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Recorded Detail
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representation of an object's true borders
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Relative Speed
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relative measurements of the speed of a radiographic film and intensifying screen system
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Remnant Radiation
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radiation resulting after the x-ray beam exits the object
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Resolution
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a measurement of the recorded detail on a radiograph
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Scatter Radiation
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radiation produced from x-ray photon interactions with matter in such a way that the resulting photons have continued in a different direction
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Source-to-Image Distance (SID)
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the distance between the source of the x-rays (usually the focal spot of the x-ray tube) and the image receptor
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Static
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unmoving
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Umbra
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true border of an object as imaged radiographically
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Anode
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positive electrode of the x-ray tube
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Bucky Mechanism
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grid that is an integral part of the x-ray table, located below the tabletop and above a cassette tray; decreases the amount of scatter radiation reaching the image receptor, which increases contrast; moves during exposure so that no grid lines appear on the image
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Cassette
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light-proof holder for the image receptor; for computed radiography, the cassette holds the reusable photostimulable phosphor imaging plate; for conventional film-screen radiography, the cassette contains intensifying screens and a sheet of film
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Cathode
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negative electrode of the x-ray tube
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Collimator
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diaphragm or system of diaphragms made of an absorbing material; designed to define the dimensions and direction of a beam of radiation
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Fluoroscope
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device used for dynamic radiographic examinations; usually consists of an x-ray tube situated underneath the x-ray table and an electronic image intensifier situated over the x-ray table
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Fluoroscopy
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examination by means of the fluoroscope
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Longitudinal
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lengthwise; along the long axis
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Spot Film Device
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equipment that permits the acquisition of static images during a dynamic fluoroscopic examination
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Transverse
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placed crosswise; situated at right angles to the long axis of a part
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Tube Angulation
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pivoting the tube at the point where it is attached to its support
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Vertical
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perpendicular to the plane of the horizon
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X-ray Tube
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device that produces x-rays
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