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22 Cards in this Set
- Front
- Back
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Five subject densities of radiology in order of least to most dense
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Air
Fat Soft Tissue Bone Metal (a fat slut bones merrily) |
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When two objects overlap, but aren't in direct contact and the overlap looks more dense
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Summation Effects
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When two objects of the same density are in direct contact and appear as a single image
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Silhouetting or Border Effacement ("kissing")
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____ radiation is produced when an electron passes near the nucleus of an atom.
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Bremsstrahlung or General
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___ radiation is produced when an electron directly hits an orbital electron, ejecting it from its orbit. Generally higher energy.
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Characteristic
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When ____ is applied, the ____ fires electrons towards the positively charged ____.
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voltage
focusing cup anode |
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kVp controls ___.
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voltage
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The reason you can see things on radiographs is due to ___.
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density interface
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What is Heel effect?
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property that x-rays produced deep inside the target have to travel further on the anode side than the cathode side
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mA controls what?
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Quantity (how mAny) of x-rays produced
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kVp controls what?
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Quality (how fast x-rays travel (kV(elocity)p)
Thicker = higher kVp needed High kVp = more black film |
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mAs controls what?
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time of exposure when using a fixed mA machine
2x mAs = 2x # of x-rays |
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What is a collimator?
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it's a device that confines x-rays to a specific region
Primarily used to reduce scatter radiation |
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What is a Compton interaction?
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Stray photons (causes scatter radiation).
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Any tissue greater than ____ should be imaged using a grid.
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10cm thick
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Which is more effective at cleaning up scatter radiation - high or low ratio grids?
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High
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What are the purpose of screens with radiograph cassettes?
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to convert x-rays to visible light
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How are detail and sensitivity related?
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Inversely.
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What is the formula for mAs?
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New mAs = original mAs x (original speed)/(New Speed)
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Sensitivity ___ with increased speed.
Detail ___ with increased speed. |
increases
decreases |
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High speed screen requires ____ radiation.
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less
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A high contrast film will have ____ shades of gray.
A long latitude film will have ____ shades of gray. |
few
many |
