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| ______ _______ are artifacts that appear on CR plates due to incomplete erasure of the previous images. |
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Definition
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| How can a ghost image on a CR plate be corrected? |
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Definition
| Additional erasure should correct the problem |
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| Digital image receptors usually have specific correction ___________ which employ interpolation techniques to assign digital values to each dead pixel, row, or column that might occur. |
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| A preprocessing technique known as __________ is a software correction that is performed to equalize the response of each pixel to a uniform x-ray beam. |
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| Image ___________ techniques are used to reduce the size of image data sets to speed up transmission of digital images and reduce storage space in the digital archive. |
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| Data compression takes advantage of _________ of data as occurs with exposure to the raw x-ray beam when all pixel values are the same. |
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| There are two types of compression techniques used to reduce the size of image data sets. They are: |
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Definition
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Term
| A data set compressed in a ________ mode is one that can be reconstructed to be exactly the same as the original image. |
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Definition
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| Lossless mode reduces the image size to __% or __% of the original image size. |
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Definition
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| For very large image files, ________ mode may not reduce the image size enough to allow for acceptable image transmission time. |
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Definition
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| _____ compression provides compression factors up to 1% (100:1), but cannot be used for image sets requiring fine detail. |
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| ______ compression cannot be used for Computer Aided Diagnosis (CAD) systems, which require uncompressed images. |
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Definition
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| Compressed images may cause CAD systems to miss lesions because of __________ _________, which usually represent a loss of data. |
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| __________ radiation can cause phantom images. |
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Definition
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| A _________ is a plot of the frequency of appearance of a given object characteristic. |
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Definition
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Term
| Object artifacts result from technologists' errors in: |
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Definition
- positioning
- collimation
- histogram selection |
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Term
| (True or False) Backscatter radiation can cause an object artifact. |
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Definition
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| (True or False) The histogram is a continuous plot of values. |
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Definition
| False - it is a discrete plot of values |
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Term
| In addition to selecting technique, the radiographer must select the appropriate ________ before each examination in order to apply the correct reconstruction algorithm to the final image. |
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Definition
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| If the x-ray field is not properly collimated, exposure field recognition errors can occur, which can lead to: |
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Definition
| histogram analysis errors |
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| What occurs when improper collimation causes signals from outside the exposure field to be included in the histogram? |
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Definition
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| Histogram analysis errors result in very _____, _____, or _____ images. |
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Definition
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Term
| If multiple fields are to be used on an IR, each must have clear, collimated edges, and margins between each field. This is known as: |
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Definition
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| (True or False) If the image field is not properly oriented with the size and dimensions of the receptor, artifacts can occur. |
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Definition
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Term
| The consistent appearance of images as required by the DICOM standard is achieved by the principle of ________ __________, meaning that changes in digital values on an image translate to equal changes in perceived brightness on the display device. |
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Definition
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Term
| Five different characteristics of display monitors must be evaluated to ensure optimum system performance: |
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Definition
1. geometric distortion
2. reflection
3. luminance response
4. display resolution
5. display noise |
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| What are the two basic types of reflection? |
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Definition
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Term
| _______ reflection is the generation of mirror images surrounding the monitor. |
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Definition
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| With _______ reflection, light is randomly scattered on the monitor. |
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Definition
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