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29 Cards in this Set
- Front
- Back
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The input screen converts x-ray photons into what?
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Light photons
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The input screen is made of what phosphor?
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Cesium iodide
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Is the input screen concave or convex?
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Concave
(minimizes distortion) |
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The photocathode does what?
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Converts light photons into electrons
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The photocathode is located immediately behind what?
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The input screen
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The photocathode is made of what phosphors?
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Antimony and cesium
(photoemissive metal) |
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The number of electrons emitted by the photocathode is ______ proportional to light photons striking the photocathode
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directly
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Electrostatic lenses are a series of ______ charged electrodes
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positively
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The electrostatic lenses dow what to the electron stream? (3)
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Focuses, accelerates, and inverts the electron stream
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The anode in the image intensifier is a ____ electrode that attracts the ______.
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positive
electrons |
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The anode is located directly in front of the ______ screen
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output
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The output screen does what?
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Converts electrons into light photons
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The output screen is made out of what phosphor?
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Zinc- cadmium sulfide
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The output screen is larger/smaller in size than the input screen?
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smaller
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Brightness gain
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Minification gain X flux gain
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Minification gain
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Concentration of photons from a large input screen onto a small output screen
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Flux gain
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Conversion of electrons to light at the output screen
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Two factors that affect the brightness
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mA (increases the number of x-ray photons)
kVp (increases the energy of x-ray photons) |
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What does ABS do?
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Increases/decreases mA and kVp during fluro to compensate for changes in tissue thickness
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A smaller input diameter of a dual image intensification tube is used for _______
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magnification
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Use of the smaller input diameter of dual image intensification tube will ________ radiation dose to the patient.
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increase
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Image resolution is measured in:
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line pairs per mm
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The _____ the intensifier tube the _______ the resolution
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smaller
greater |
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A thinner input screen with small phosphor crystals has better or worse resolution?
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Better
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A grainy or blotchy appearance cause by insufficient radiation to produce a uniform image
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Quantum mottle (noise)
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The most common solution to mottle is to increase _____
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mA
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Vignetting distortion
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A loss of brightness at the edge of the image
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Pincushion distortion
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Increased magnification at the periphery of the timage
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Pincushion and vignetting distortion are due to what?
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The curvature of the input screen
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