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28 Cards in this Set
- Front
- Back
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Contrast
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How sharply dark and light areas are differentiated or separated on an image; the difference in the degrees of blackness (densities) between adjacent areas on a dental radiograph.
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Contrast, high
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A term describing an image with many very dark areas and very light areas and few shades of gray.
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Contrast, long-scale
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A term describing an image with many densities, or many shades of gray; long-scale contrast results from the use of a higher kilovoltage range.
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Contrast, low
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A term describing an image with many shades of gray and few areas of black and white.
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Contrast, scale of
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The range of useful densities seen on a dental image.
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Contrast, Short-scale
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A term describing an image with only two densities, areas of black and white; short-scale contrast results from the use of a lower kilovoltage range.
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Contrast, subject
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The characteristics of the subject that influence radiographic contrast; characteristics include thickness, density, and composition of the subject.
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Density
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The overall darkness or blackness of an image.
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Distance, object-receptor
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One of the influencing factors of image magnification; refers to the distance between the object being radiographed (e.g., tooth) and the receptor; less image magnification results when the tooth and the receptor are as close as possible.
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Distance, target-receptor
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One of the influencing factors of image magnification; refers to the distance between the source of x-rays and the receptor; less image magnification results when a longer position-indicating device (PID) is used.
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Distortion
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A geometric characteristic that refers to a variation in the true size and shape of the object being radiographed; radiographic distortion is influenced by object-receptor alignment and x-ray beam angulation.
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Exposure factors
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Factors that influence the density of a radiograph (e.g., milliamperage, kilovoltage, exposure time).
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Exposure time
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The interval during which x-rays are produced.
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Focal spot
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The tungsten target of the anode; converts bombarding electrons into x-ray photons, concentrating the electrons and creating an enormous amount of heat.
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Magnification
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A geometric characteristic; refers to a radiographic image that appears larger than the actual size of the object it represents; influenced by target-film distance and object–receptor distance.
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Milliamperage
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In radiography, the quantity, or number, of x-rays emitted from the tubehead; measured in milliamperes.
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Operating kilovoltage peak
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The maximum or peak voltage that is used during an x-ray exposure.
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Penumbra
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The fuzzy, unclear area that surrounds a radiographic image.
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Radiograph, diagnostic
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A radiograph that provides much information with images that have proper density and contrast, have sharp outlines, and are of the same shape and size as the object being radiographed.
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Radiolucent
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The portion of an image that is dark or black; a radiolucent structure readily permits the passage of the x-ray beam and allows more x-rays to reach the receptor.
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Radiopaque
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The portion of an image that is light or white; a radiopaque structure is one that resists the passage of the x-ray beam and limits the amount of x-rays that reach the receptor.
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Sharpness
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Refers to the capability of the receptor to reproduce the distinct outlines of an object; influenced by focal spot size, film composition, and movement.
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Stepwedge
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A device constructed of uniform-layered thicknesses of an x-ray absorbing material, usually aluminum; different steps absorb varying amounts of x-rays and are used to demonstrate film densities and contrast scales.
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Subject thickness
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The thickness of soft tissue and bone in a patient.
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Differentiate between radiolucent and radiopaque areas on a dental radiograph
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Radiolucent= appears dark or black
Radiopague=appears light or white |
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Describe a diagnostic dental radiograph
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-images exhibit proper density and contrast
-have sharp outlines -are the same shape and size as the object radiographed |
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List the two visual characteristics of the radiographic image
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Density and contrast
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List the factors that influence density (4)
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1) Milliamperage (MA)
-MA-the intensity of x-rays that expose the film -Increase MA=increase in density (darker film) 2) KiloVoltage peak (KVp) -KVp-maximum voltage (energy) used during an exposure -Increase KVp=increase in density (overall darkness 3) Exposure time (impulses) 1/60 of sec -Exposure time affects the number of x-rays that reach the film - Increase exposure=increase number= increase in density 4) Subject thickness (size of patient) -if the person is larger that has more mass, you must increase the exposure time |
