RADT 146 Unit 5 exam with verified solutions

as scatter increases, radiographic density _____ - correct answer ✔-increases
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As radiation field size decreases , scatter ____ - correct answer ✔-decreases
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what part of the useful beam will you find the most blur (penumbra) - correct
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answer ✔-at the edge of the beam
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as the tissue thickness decreases, scatter ____ - correct answer ✔-decreases
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what is the radiation called that is not produced at the focal spot (target)? -
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correct answer ✔-off-focus
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-extra focal/




-stem radiation
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main advantage of a positive beam limiter - correct answer ✔-increases image
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quality by decreasing scatter to the IR
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what happens to patient exposure when the field size increases - correct
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answer ✔-increases
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what happens to detail when the field size decreased - correct answer ✔-
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increases

, what is the purpose of the upper set of shutters on an automatic collimator? -
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correct answer ✔-control stem radiation/absorb off-focus radiation
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what is the purpose of the lower set of shutters on an automatic collimator? -
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correct answer ✔-reduce blur
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what happens to radiographic contrast as scatter radiation is increased? -
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correct answer ✔-decreases
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where is the grid placed? - correct answer ✔-between the patient and the IR
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what is the purpose of the grid? - correct answer ✔-improve contrast and detail
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by reducing scatter to the IR
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what does a grid do? - correct answer ✔-allows straighter photons carrying the
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aerial image to reach the IR
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true or false: grids are used for body parts greater than 10cm - correct answer
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✔-true
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when a grid is used, density is decreased. what must be done to counter act
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this? - correct answer ✔-the technical factors must be increased
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what does an increase in technical factors result in? - correct answer ✔-
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increased patient exposure / /