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Related Flashcards
Cards In This Set
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What is beam hardening?
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Is higher attenuation energy do to the loss of the low energy xrays which are absorbed.
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Is beam hardening increased or decreased when going through bone?
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Increased
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Is beam hardening when it goes through fat?
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Decreased
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How is beam hardening effected when going through a distance?
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Increased-Low energy xrays can't travel as far
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Where is the Beam hardening located in regards to the image?
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The outside to the center- sometimes called the "cupping artifact"
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What is a Volume Averaging Artifact?
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It is the computer algorithm averaging out the voxels which can cause a blur or also even omit small pathologies.
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How can one go about getting rid of Volume Averaging Artifacts?
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Using thinner slices
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Whenever one uses smaller slices to omit artifacts, what must be done to the mas?
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Should be increased because when decreasing slice thickness, noise is increased.
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Motion artifacts is an artifact that can mostly be controlled by the technologist. What is the easiest way to control pt voluntary motion?
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CLEAR INSTRUCTIONS
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What are the 2 types of motion? Name a few
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Voluntary- breathing, head turning
involuntary-heartbeat, spasm, pt is cold
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Why does metal cause an artifact on scans?
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Metal is too dense for the xrays to penetrate though which causes a star appearance on the exam.
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What is the main cause of the Edge Gradient artifact?
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Different shapes and densities.
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How does the edge gradient appear on an exam?
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Appears as straight lines.
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What is one factor that directly effects the edge gradient artifact?
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Detector aperature size, decreasing size of aperature=decrease in effects.
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What is two things a can a Technologist do to reduce the edge gradient artifact?
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Move the pt so thickness is more within the view of the voxel, also thinner slices.
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