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SPRING 2024: Principles II > UNIT 3 REVIEW ASSIGNMENT AND EXAM > Flashcards

UNIT 3 REVIEW ASSIGNMENT AND EXAM Flashcards

1
Q

A QC test performed by Radiographers in order to assess for detector malfunctions and flaws in the acquisition process

A. Flat Field Uniformity tests
B. Exposure field recognition
C. Partitioned pattern separation
D. Windowing

A

A. Flat Field Uniformity tests

Flat field uniformity , gain or off set gain corrections attempt to even out the signal across the area of the image field. The variance of the signal can be caused by dead or malfunctioning pixels, rows or columns; image lag , anode heel effect or calibration errors.

Exposure field recognition separates areas of the image by scatter noise, raw exposure and midrange gray levels for histogram analysis.

Partitioned Pattern Separation or segmentation is used in CR to separate multiple exposures taken on a single IP.

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2
Q

Irrelevant contrast that exists in an image is termed _________ and is measured by _____________

A. Contrast noise; CNR
B. Signal noise; SNR
C. Region of interest; area in mm
D. Standard deviation; mean

A

A. Contrast noise; CNR

Irrelevant contrast that exists in an image is contrast noise; measured by the contrast to noise ratio (CNR). SNR is the measure of the ratio of noise to the signal in a system. The mean is the average of the pixel values in a region of interest measurement (ROI). ROI’s are used by radiologists to help identify the size and consistency of tissue within a specified region. The CNR can be calculated by region of interest measurements (ROI) usually by the medical physicist.

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3
Q

Which type of detail processing is better suited to remove random noise such as quantum mottle?

A. High-pass filters
B. Intensity processing
C. Frequency processing
D. Kernels

A

D. Kernels

Kernels in the spatial domain are better suited to reduce random noise such as quantum mottle. Low-pass filters in the frequency domain are better suited for removing periodic noise, such as electronic noise or aliasing.

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4
Q

The type of algorithms used to take input digital data and produce output analog data in the form of an image are known as:

A. Image to information transformations
B. Image to image transformations
C. Information to image transformations

A

C. Information to image transformations

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5
Q

Identify the labeled areas of the histogram in the image below:

Smin
Smax
Tail
Threshold
Value of interest

A

A. Threshold
B. Smin
C. Value of interest
D. Smax
E. Tail

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6
Q

Which of the following is/are test pattern(s) that could be used to assess the characteristics of a medical image viewing monitor?

SMPTE
ADC
DICOM
TG-18

A

SMPTE
TG-18

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7
Q

In digital imaging, image contrast is primarily controlled by

A. LUT
B. TFT
C. kVp
D. DAC

A

A. LUT

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8
Q

Which of the following are considered operator adjustments that can be made to a processed image? (select all that apply)

Flat fielding or gain corrections
Histogram analysis
Partition pattern separation (segmenting)
Image zoom
Image invert
Image flip or rotate
Annotation

A

Image zoom
Image invert
Image flip or rotate
Annotation

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9
Q

A function that estimates an unknown value from two or more known values by taking an average of the values surrounding it is called

A. Fourier Transform
B. Histogram
C. Interpolation
D. Convolution

A

C. Interpolation

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10
Q

A term used to describe the application of the LUT is

A. Post-processing
B. Gradient processing
C. Brightness processing
D. Frequency processing

A

B. Gradient processing

Gradient processing can be applied on two occasions: first, during default preprocessing when the anatomic LUTs are applied; then again anytime the displayed image is windowed by the operator

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11
Q

The function of the TFT panel in the LCD monitor is to:

A. Turn the backlight on and off
B. Improve spatial resolution
C. Apply current to liquid crystal
D. Convert the light to electrons

A

C. Apply current to liquid crystal

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12
Q

Edge enhacements are made in the spatial domain using:

A. Flatfield Corrections
B. The LUT
C. The Fourier Transform
D. Kernels

A

D. Kernels

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13
Q

Which of the following are considered hard copies of images? (select all that apply)

Displayed on a monitor
Paper
Film

A

Paper
Film

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14
Q

A region of interest (ROI) is used in digital imaging to:

A. Provide appropriate contrast to the image
B. Rescale the histogram
C. Measure the Contrast to Noise Ratio (CNR)
D. Determine the total SNR

A

C. Measure the Contrast to Noise Ratio (CNR)

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15
Q

Match the following histogram analyses with their definitions.

Type 1 Histogram
Type 2 Histogram
Type 3 Histogram

-Histogram has a spike in the white side and sometimes a tail. Used for contrast studies such as SBS and BE.
-Histogram has a tail. Used for images with large areas of direct exposure.
-Histogram has no spike in the white or the black region. Used for images in which anatomy fills the entire field.

A

-Type 1: Histogram has a tail. Used for images with large areas of direct exposure.
-Type 2: Histogram has no spike in the white or the black region. Used for images in which anatomy fills the entire field.
-Type 3: Histogram has a spike in the white side and sometimes a tail. Used for contrast studies such as SBS and BE.

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16
Q

A method for scoliosis imaging that involves three images that are taken and patched together is referred to as:

A. Dual energy subtraction
B. Unsharp masking
C. Digital Subtraction Angiography
D. Image stitching

A

D. Image stitching

In CR three IPs are aligned with a special mesh grid to ensure registration between images. These are usually taken with one exposure. This is a disadvantage with the central ray not centered over the extreme ends of the body part. In DR the same detector is used, moved from one location to the next, requiring only two exposures. See the posted manufactures brochures on Image Stitching for more information on how the major manufactures achieve this

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17
Q

What is the difference between masking or cropping and exposure field recognition (EDR/EFR)?

A. EDR /EFR is a preprocessing function that separates exposure areas assisting with accurate histogram analysis, while masking is a post processing function that does not improve histogram analysis.
B. Masking is a post processing function that is used to take the place of collimation and improves patient dose, while EDR/EFR does not improve patient dose.
C. There is no difference. They are the same thing.
D. EDR/EFR and masking are both preprocessing operations that improve the contrast in the image, but masking does it better

A

A. EDR /EFR is a preprocessing function that separates exposure areas assisting with accurate histogram analysis, while masking is a post processing function that does not improve histogram analysis.

EDR /EFR is a preprocessing function that separates exposure areas assisting with accurate histogram analysis, while masking is a post processing function that does not improve histogram analysis.
Masking does not take the place of proper collimation and should only be done to reduce the effects of veil glare on the image.

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18
Q

In digital radiography, the latent image is acquired in _____________ form on the _______________

A. digital; monitor
B. digital; image receptor
C. analog; image receptor
D. analog; monitor

A

C. analog; image receptor

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19
Q

If a radiographer applied the ankle LUT to a chest radiograph, the image would likely demonstrate:

A. Extremely low resolution
B. Low contrast
C. High contrast
D. A loss of contrast

A

C. High contrast

A chest image processed with an ankle LUT would demonstrate high contrast. This is because the reference ankle LUT, associated with the procedure algorithm for an ankle, is designed to display appropriate high contrast for an extremity image. The computer software will rescale or modify the brightness and contrast to match the selected procedure algorithm regardless of the actual input. However, the radiographer can correct for improper histogram selection prior to sending the image to PACS.

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20
Q

A histogram is:

A. A post processing technique
B. A table of numbers that represents a “normal” image for the selected procedure
C. A graph that plots the number of pixels assigned to each code value in the digital image
D. Created using a frequency processing technique

A

C. A graph that plots the number of pixels assigned to each code value in the digital image

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21
Q

Smoothing filters remove: (select all that apply)

Details
Fine edges
Noise
Large structures

A

Details
Fine edges
Noise

Smoothing filters remove the fine edges of structures, removes noise and removes details. This are typically referred to as low pass filters because, small objects with high frequency are filtered out and large low frequency objects are allow to pass. Smoothing filters are used to remove noise in an image.
High pass filters do the opposite, they filter low frequency objects such as low contrast objects and leave high frequency objects or fine details. These algorithms are used to sharped fine structural lines, but introduce more noise in in the image

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22
Q

A special type of imaging that produces soft tissue only and bone only images simultaneously:

A. Digital tomography
B. Digital Subtraction Angiography
C. Dual Energy Subtraction
D. Double Exposure Radiography

A

C. Dual Energy Subtraction

Dual energy subtraction uses a high energy and a low energy images to produce separate image of bones and soft tissues. There are two methods: In the first method, two separate images are produced at different kVp levels and the tissues of interest are subtracted out. The advantage of this method is that the tissue selected images have better signal. The disadvantages are that the patient dose is higher and there may be mis-registration b/t images due to patient motion. 2. In the second method, one image is produced with a special filtered cassette for high and low energies and the tissues of interest are subtracted. The disadvantage of this method is the the tissue selected images have more noise which may lead to obscuring of detail.

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23
Q

Sources of noise in an imaging system include: (select all that apply)

Dark current
High SNR
Dark noise
Appropriate shielding
Low signal
Light scatter in indirect capture DR systems

A

Dark current
Dark noise
Low signal
Light scatter in indirect capture DR systems

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24
Q

The bit capacity of the quantizer in the ADC represents the:

A. The pixel bit depth of the system
B. The dynamic range of the system
C. Number of gray levels the system can render
D. All of these

A

D. All of these

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25
Q

Select the true statements about Q values. (select all that apply)

-The values change dramatically with the input values
-They are permanently stored values
-It represents input data
-They are fixed values, no matter what the input values are

A

They are permanently stored values
They are fixed values, no matter what the input values are

Q-values are a fixed (do not change) predetermined table of reference values permanently stored in the computer based on the dynamic range of the system. The input pixel data are arranged into bins and assigned S-Values starting from the SMIN, to the SMAX

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26
Q

The amount of time it takes for the crystal layer of the LCD to go from an on to an off state is termed:

A. Aspect ratio
B. Angular dependence
C. Decimation time
D. Response rate

A

d. response rate

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27
Q

A DICOM standard that ensures that all radiographic display systems must provide consistent appearances of grayscale from display to display is termed:

A. DICOM
B. SMPTE
C. GSDF
D. TG-18

A

C. GSDF

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28
Q

Which of the following would be considered a primary display monitor?

A. The modality workstation
B. The technologist’s workstation
C. The radiologist’s workstation
D. The physician station in the ER

A

C. The radiologist’s workstation

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29
Q

Detail processing can be performed in either the spatial domain or the frequency domain.

A. True
B. False

A

A. True

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30
Q

An algorithm that is designed to allow high frequency signals to pass to the image and suppresses the signal from low frequencies is termed:

A. Low pass filter
B. Interpolation
C. High pass filter
D. Grayscale filter

A

C. High pass filter

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31
Q

All of the following are advantages of the LCD over the CRT. (select all that apply)

Lightweight
Less heat production
Lower energy consumption
Angular dependence

A

Lightweight
Less heat production
Lower energy consumption

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32
Q

Which function curve in the image below demonstrates long scale contrast?

A

B

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33
Q

The histogram is selected by:

A. Radiographer, after the image is displayed on the monitor
B. During the Rescaling step of processing
C. The radiographer, prior to processing
D. Defaut processes within the computer

A

C. The radiographer, prior to processing

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34
Q

Image pre-processing includes: (select all that apply)

Field Uniformity
Window leveling
Noise corrections
Detail processing
Histogram formation

A

Field Uniformity
Noise corrections
Histogram formation

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35
Q

An increase in dark current will ___________ the DQE

A. Increase
B. Decrease
C. Have no impact

A

B. Decrease

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36
Q

Due to the Cosine law, it is best to view an x-ray image on a display monitor:

A. From a significant angle
B. Extremely close up
C. Straight on (not at an angle)
D. From a distance

A

C. Straight on (not at an angle)

When the monitor is viewed from an angle both the contrast and luminance is reduced. This is called angular dependence. The best viewing angle of a digital display device is straight on. As you have seen in our labs image quality is reduced when viewing medical images from an angle.

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37
Q

Another term for dark current is:

A. Electronic noise
B. Quantum noise
C. Ambient noise
D. Scatter

A

C. Ambient noise

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38
Q

On a digital system, the average brightness or center of the gray scale is termed the:

A. Slope or curve
B. Window width
C. Smax
D. Window level

A

D. Window level

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39
Q

A(n) _____________ is applied to the data that has standard contrast for that exam to give the desired image contrast for display

A. Smax
B. LUT
C. Flat field correction
D. Histogram

A

B. LUT

A look up table (LUT) is applied to the data that contains the standard contrast for that exam to give the desired image contrast for display. To generate a histogram the scanned area is divided into pixels and the signal intensity for each pixel is determined. SMAX is the maximum value of interest (VOI) determined by the computer to be used in histogram analysis. Flat field corrections are applied to correct for flaws in field uniformity.

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40
Q

When the acquisition matrix is larger than the viewing matrix, the information must be sampled. This refers to:

A. Kernels
B. Interpolation
C. Decimation
D. Data clipping

A

C. Decimation

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41
Q

When the image data is narrowed to fit the latitude or slope of the selected protocol, image information can be lost. This refers to:

A. Image inversion
B. Edge detection
C. Data clipping
D. Segmenting

A

C. Data clipping

When too much data clipping occurs, the radiologist does not have enough latitude or range of values to perform windowing in PACS. It is important for the radiologist to have as much windowing latitude as possible for diagnosis. Once again, the technologist should avoid sending images to PACS that have been windowed at the QC workstation.

42
Q

The exposure indicator (S#) is the same as:

A. Smax
B. Savg
C. Values of interest (VOI)
D. Smin

A

B. Savg

43
Q

A device used to measure the brightness response of a digital display monitor is:

A. Caliper
B. Step wedge
C. Line pair test tool
D. Photometer

A

D. Photometer

44
Q

Exposure field or data recognition are algorithms used to:

A. Superimpose areas of the image
B. Recognize and separate information around a collimated border
C. Create a longer contrast scale
D. Assign a code value

A

B. Recognize and separate information around a collimated border

Exposure field or data recognition are algorithms used to separate ares in the image such as the collimated borders, raw exposure areas and midrange gray areas.

45
Q

How does the computer correct for malfunctioning pixels or detector elements?

A. Fourier transform
B. Geometric processing
C. Interpolation
D. Reverse Fourier transform

A

C. Interpolation

Interpolation is a operation that estimates an unknown value from the surrounding values. To correct the data for a dead pixel, the surrounding pixels are sampled and averaged and the result in inserted for the value of the dead pixel. This does not actually fix the pixel, but uses an approximate for the pixel’s value. If many pixels malfunction, the entire detector may need to be replaced. Fourier and reverse Fourier Transform are algorithms that change how the computer sorts the digital image data. Geometric processing are function that change the size or orientation of the image on the display monitor.

46
Q

Image noise that occurs all in the same frequency band can be eliminated or reduced by:

A. Band-pass processing
B. Kernels
C. Histogram rescaling
D. Reshooting the image is the only way to reduce this artifact

A

A. Band-pass processing

Frequency filtering is an example of filtering in the frequency location domain in which the digital signal is sorted by the size of objects in the image, algorithms are then applied to one or more frequency layers changing the output image in some way.

47
Q

Analog to digital conversion converts the latent image information into:

A. An x-ray beam
B. An electron cloud
C. Binary code
D. The displayed image

A

C. Binary code

48
Q

Rescaling corrects for:

A. Exposure Field Recognition errors
B. Non parallel collimation
C. Slight over or under exposure
D. The technologist selecting the wrong LUT

A

C. Slight over or under exposure

49
Q

How can a technologist minimize the effects of dark noise on a CR image?

A. Check the S# and repeat as needed
B. Increase the kVp and use the largest cassette possible
C. Ensure the IP is erased prior to use and processed immediately after the exposure
D. Collimate evenly on at least two sides

A

C. Ensure the IP is erased prior to use and processed immediately after the exposure

For CR, dark noise is an accumulation of radiation on the IP either before or after exposure. Any cause of noise on the image can reduce visibility of detail. The way way to minimize this type of noise is to ensure the IP is erased just prior to use and processed immediately after exposure.

50
Q

Put the processing steps in order

Flatfielding
Detail processing
Exposure Field Recogntion
Gradation processing
Formatting for display
Histogram Formation
Noise Reduction
Rescaling

A
  1. Flatfielding
  2. Noise Reduction
  3. Exposure Field Recogntion
  4. Histogram Formation
  5. Rescaling
  6. Gradation processing
  7. Detail processing
  8. Formatting for display
51
Q

The total number of gray shades available for the computer to select from is called the:

A. Histogram
B. Image Contrast
C. Look Up Table
D. Gray Scale Bit depth

A

D. Gray Scale Bit depth

52
Q

Larger objects in the image have ____________ spatial frequency.

A. High
B. Low

A

B. Low

53
Q

With multi-frequency processing, images are:

A. Separated into multiple layers or bands for processing
B. Decreased in size
C. Increased in dynamic range or signal
D. Converted into varying brightness levels

A

A. Separated into multiple layers or bands for processing

54
Q

The purpose of the TFT panel in the LCD monitor is to:

A. Change the color that is displayed on the monitor
B. Apply a current to the Liquid crystal layer
C. Convert the signal to analog form
D. Convert the light to electrons

A

B. Apply a current to the Liquid crystal layer

55
Q

In the image below, which of the following two curves represents an image with longer scale contrast?

A. Curve A
B. Curve B

A

Curve B

56
Q

A post processing tool used for body length studies, such as scoliosis, where multiple images are taken and then digitally combined to form a single seamless image:

A. Dual energy subtraction
B. Spatial filtering
C. Frequency filtering
D. Image stitching

A

D. Image stitching

57
Q

Current moving in the electronics of the detector in the absence of x-ray exposure is termed:

A. Field uniformity
B. Dark current
C. DEL drop out
D. Dark noise

A

B. Dark current

58
Q

A QC test performed on a digital detector by producing an image on the receptor without any attenuating material in the field of view is called:

A. Segmentation
B. SMPTE or TG-18 test pattern
C. Gain calibration or field uniformity test
D. Interpolation

A

C. Gain calibration or field uniformity test

59
Q

A technique that uses a high energy image and a low energy image to produce separate images of bones and soft tissues.

A. Dual energy subtraction
B. Dynamic range control
C. Image stitching
D. Unsharp mask

A

A. Dual energy subtraction

60
Q

What type of algorithms can be used during image pre-processing to correct for dead pixels?

A. Decimation
B. Acquistion
C. Extrapolation
D. Interpolation kernels

A

D. Interpolation kernels

61
Q

The steps before image display that are taken to correct errors in the raw acquisition

A. Pre-processing
B. Post-processing
C. Frequency processing
D. Histogram creation

A

A. Pre-processing

62
Q

A gain calibration test is used to test:

A. Uniformity of the detector response
B. The Anode Heel effect
C. Automatic Exposure Control malfunctions
D. Spatial resolution

A

A. Uniformity of the detector response

63
Q

Removing non-contrast enhanced tissue from an image while keeping the contrast enhanced tissue describes:

A. Image Stitching
B. Dual Energy Subtraction
C. Re-processing
D. Digital Subtraction Angiography (DSA)

A

D. Digital Subtraction Angiography (DSA)

64
Q

Which of the following monitors would be considered a primary display?

A. Radiographer’s workstation
B. PACS monitor in the ICU
C. Radiologist’s monitor
D. Image Acquisition monitor

A

C. Radiologist’s monitor

65
Q

Which of the following algorithms functions to improve the visibility of fine details while also increasing image noise?

A. Image inversion
B. Edge enhancement
C. Image flip
D. Smoothing

A

B. Edge enhancement

66
Q

When the acquisition matrix is smaller than the viewing matrix, the information is averaged together to fill in the missing information. This refers to:

A. Interpolation
B. Decimation
C. Data clipping
D. Kernels

A

A. Interpolation

67
Q

Which of the following is/are changed when the LUT is changed? (select all that apply)

Contrast Scale
The slope or gradient of the contrast curve
Image Contrast
The grayscale bit depth

A

Contrast Scale
The slope or gradient of the contrast curve
Image Contrast

68
Q

All of the following are considered advantages of the LCD monitor when compared to the CRT. (select all that apply)

Generate less heat
Brighter
Easily fits on a desktop
Angular Dependence
Lightweight

A

Generate less heat
Easily fits on a desktop
Lightweight

69
Q

In CR, the IP should be erased immediately before use because:

A. Dark noise can accumulate on the IP
B. A row of pixels can drop out causing mis-calibration
C. The anode heel effect can cause a non-uniform x-ray field
D. An increase of current can cause signal drop out

A

A. Dark noise can accumulate on the IP

70
Q

The operator adjustment that controls the range of shades of gray that will be displayed is:

A. Window width
B. Edge enhancement
C. Rescaling
D. Window level

A

A. Window width

71
Q

An operator adjustment that adjusts brightness similiarly to rescaling is:

A. Changing the window level
B. Adding an annotation
C. Image-flip
D. Changing the window width

A

A. Changing the window level

72
Q

According to the ARRT, the term brightness refers to:

A. The visible difference between any two selected areas of brightness on the monitor
B. The measurement of the luminance of the area in a radiographic image displayed on the monitor
C. The center of the window level
D. The number of gray shades visible on the image linked to the bit depth of the system

A

B. The measurement of the luminance of the area in a radiographic image displayed on the monitor

73
Q

All of the following steps are considered part of post-processing. (select all that apply)

Operator adjustments
Detail processing
Gradation processing
Flat fielding

A

Operator adjustments
Detail processing
Gradation processing

74
Q

In the image below, the area of the histogram that the arrow is pointing to is:

A. Tail
B. Smax
C. Savg
D. Threshold

A

B. Smax

75
Q

A set of QC test patterns used to measure qualilty of the display monitor

A. Spatial frequency filter
B. Task-Group 18
C. Photometer
D. Line pair test tool

A

B. Task-Group 18

76
Q

Changes to the average image brightness level of the acquired image to match the average brightness level of the selected reference image is accomplished by:

A. Applying a medium contrast LUT
B. Using a global operation
C. Using a smoothing filter
D. Rescaling the histogram

A

D. Rescaling the histogram

77
Q

Select whether the types of signals listed below are analog or digital.

-Digital x-ray image displayed on the viewing monitor
-Computer language used to process data
-The latent image stored on a digital image receptor
-An electron beam signal sent from the TFT

A. Digital
B. Analog

A

Digital x-ray image displayed on the viewing monitor: B
Computer language used to process data: A
The latent image stored on a digital image receptor: B
An electron beam signal sent from the TFT: B

78
Q

A region of interest (ROI) is used in digital imaging to:

A. Rescale the histogram
B. Measure the CNR
C. Provide appropriate contrast to the image
D. Determine the SNR

A

B. Measure the CNR

79
Q

The DICOM standard that requires a consistent standard gray scale appearance from display to display is called:

A. Grayscale Standard Display Function
B. Task Group 18 standard
C. The NEMA standard
D. Society of Motion Picture and Television Standard

A

A. Grayscale Standard Display Function

80
Q

If a radiographer performs a PA hand x-ray and accidentally processes it as a PA chest, what could likely happen to the image? (select all that apply)

The exposure indicator will not be accurate
The contrast will be long scale
The EFR will likely fail
The image could be either too dark or too bright

A

The exposure indicator will not be accurate
The contrast will be long scale
The image could be either too dark or too bright

81
Q

Periodic noise on an image receptor might be repaired by using:

A. Kernels in the spatial domain
B. Gradation processing
C. Mulit-frequency processing
D.Edge enhancement filters in the frequency domain

A

C. Mulit-frequency processing

82
Q

The Savg is used to determine:

A. The overall image contrast
B. Which histogram to use
C. Average exposure to the image receptor
D. The total patient dose

A

C. Average exposure to the image receptor

83
Q

A pre-processing algorithm that separates the non-exposure areas such as scatter and off-focal radiation outside the collimated borders from exposure areas inside the collimation is called:

A. Exposure field recognition
B. Frequency filters
C. Segmentation
D. Flat field processing

A

A. Exposure field recognition

84
Q

Perceptual linearization describes the concept:

A. Where images appear lighter than their actual reference histograms
B. Of the Inverse Square Law
C. Where equal changes in digital values result in equal changes in perceived brightness at the display.
D. Of angular dependence and Cosine’s Law

A

C. Where equal changes in digital values result in equal changes in perceived brightness at the display.

85
Q

Flat field non-uniformity refers to:

A. Separating multiple exposures taken on a single IP
B. The variance of the signal across the area of the image field
C. Changes to the look up table for displayed image contrast
D. Separating the areas of the image for histogram analysis

A

B. The variance of the signal across the area of the image field

86
Q

Data clipping ocurs when:

A. The LUT is applied
B. There is too much quantum mottle
C. The image receptor is overexposed
D. The technologist excessively windows the image before sending to PACS

A

D. The technologist excessively windows the image before sending to PACS

87
Q

A histogram is:

A. A graph that plots the number of pixels assigned to each code value in the digital image
B. Created using frequency processing techniques
C. A table of numbers that represent a normal image for the selected procedure
D. A post-processing technique

A

A. A graph that plots the number of pixels assigned to each code value in the digital image

88
Q

What type of detail processing is best to remove random noise?

A. Frequency processing
B. Smoothing
C. High-pass filtering
D. Intensity processing

A

B. Smoothing

89
Q

In the image below, the area of the histogram that the arrow is pointing to is called the:

Tail
Smax
Threshold
Smin

A

Threshold

90
Q

The level of brightness of each pixel on the LCD display corresponds to:

A. The Cosine Law
B. A digital value converted to an analog voltage signal from the DAC
C. The amount of electricity supplied to the backlight
D. The size of the matrix

A

B. A digital value converted to an analog voltage signal from the DAC

91
Q

A filter that subtracts a blurred image from the original image, producing a new subtracted, sharper image is called:

A. A low-pass filter
B. Interpolation
C. A kernel
D. Unsharp mask

A

D. Unsharp mask

92
Q

An image displayed on a computer monitor is called a:

A. Hard copy
B. Soft copy

A

B. Soft copy

93
Q

All of the following are components of an LCD monitor. (select all that apply)

Polarized filter
TFT panel
Electron gun
Liquid Crystals
Image matrix
Backlight

A

Polarized filter
TFT panel
Liquid Crystals
Backlight

94
Q

A type of Histogram analysis that expects a tail, or a spike in the area of direct exposure is called:

A. Type 3
B. Type 1
C. Type 2
D. Type 4

A

B. Type 1

95
Q

A(n)____________ is a simple table with two columns: one for input and one for output used to change the displayed contrast scale

A. Look up table
B. Rescaling algorithm
C. Edge enhancement filter
D. Histogram

A

A. Look up table

96
Q

All of the following might lead to a histogram analysis error. (select all that apply)

-Placing part of the lead apron in the light field
-Collimating equally on all four sides of the part
-Selecting the wrong procedure algorithm from the menu
-Off-centering the anatomy on a CR Image receptor
-Uneven collimation

A

-Placing part of the lead apron in the light field
-Selecting the wrong procedure algorithm from the menu
-Off-centering the anatomy on a CR Image receptor
-Uneven collimation

97
Q

The following statement is true about LCD monitors:

A. The room lights should be turned up as bright as possible
B. It is alright to see reflections on the screen
C. Images should be viewed straight on, and not from an angle
D. There should be at least two bright lights on behind the viewer

A

C. Images should be viewed straight on, and not from an angle

98
Q

Electronic masking improves image quality and reduces patient dose

A. True
B. False

A

B. False

Masking is a post-function process, it does not affect patient dose

99
Q

A ____________________ is used to measure the brightness of the viewing monitor.

A. Star test pattern
B. Luminance meter
C. Line pair test tool
D. Electron gun

A

B. Luminance meter

100
Q

Which curve represents an image with an inverted contrast scale?

A. Curve C
B. Curve B
C. Curve A
D. None of them

A

C. Curve A

101
Q

UNIT 3 KAHOOT REVIEW LINK

A

https://create.kahoot.it/share/radr-2205-unit-3-review/c912e88c-9739-4706-b177-66b60e97dbf4

SPRING 2024: Principles II (13 decks)

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