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Cards In This Set
| Front | Back |
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Do you view CT images from the head or the feet?
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The feet
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What is the unit used for the CT value?
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Hounsfield unit (HU)
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What is the HU for bone?
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1000 (White)
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What is the HU for muscle?
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80
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What is the HU for white and grey matter, respectively?
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45 and 40
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What is the HU for blood and CSF, respectively?
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20 and 15
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What is the HU for water?
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0 (grey)
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What is the HU for fat and lungs respectively?
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-100 and -200
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What is the HU for air?
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-1000 (black)
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Describe the overall process of a CT scan from beginning to end
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Preparation of patient and scanner - position the patient - select protocol - enter patient details - complete scout scan - perform acquisition - patient leaves - image processing/reconstructing and archiving - radiologist report
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What is CT pitch?
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The CT table movement through the acquisition
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How do you calculate pitch?
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Pitch = [table movement speed (mm/s) x rotation time (s)] / slice thickness (mm)
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Will the scan extent be altered when pitch is adjusted (if all other factors are equal)?
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Yes
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What is a convolution filter?
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It is an algorithm/kernel applied to raw data (eg. edge enhancement)
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What is the window width and window levels for cerebral tissues?
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WW 100-150, WL 40-60
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