CT scanner components, slice acquisition concepts, and windowing basics tested on radiologic technology certification exams.
35 cards · basic cards · AI-written, checked twice. Edit anything.
- What does the acronym CT stand for in medical imaging?
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Computed Tomography- What is the gantry in a CT scanner?
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The ring-shaped housing that contains the x-ray tube, detector array, and related components, through which the patient passes- What does slip ring technology allow a CT gantry to do?
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Rotate continuously in one direction without cables twisting, enabling helical (spiral) scanning- Water has a Hounsfield Unit (HU) value of ____.
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0- Air has a Hounsfield Unit (HU) value of approximately ____.
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-1000- What is the approximate Hounsfield Unit range for fat?
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About -100 to -60 HU- What is the approximate Hounsfield Unit range for dense compact bone?
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About +1000 to +3000 HU- What does window width (WW) control in a CT image?
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The range of CT numbers (HU) displayed across the grayscale, which determines image contrast- What does window level (WL) represent in a CT image?
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The midpoint HU value of the window width, centering the grayscale on a tissue of interest- A narrow window width produces what kind of image contrast?
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High contrast, with fewer shades of gray spread over a small HU range- A wide window width produces what kind of image contrast?
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Low contrast, with many shades of gray spread over a large HU range- What is pitch in helical (spiral) CT?
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The ratio of table travel per gantry rotation to the slice (beam) thickness- What does a pitch of 1 mean in helical CT?
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The table moves a distance equal to one slice thickness during each gantry rotation- What is the function of the detector array in a CT scanner?
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It converts transmitted x-ray photons that pass through the patient into electrical signals- What does the Data Acquisition System (DAS) do in CT?
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Converts the analog electrical signal from the detectors into digital data for image reconstruction
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