Deck 4: Digital Imaging

Question 1

A 10-bit depth can display how many shades of gray?

A) 10
B) 1024
C) 4096
D) 16,384

Answer 1

1024

Question 2

A system that can digitize and display a greater number of shades of gray will have ____________ contrast resolution.

A) increased
B) decreased
C) no

Answer 2

increased

Question 3

Digital imaging processing refers to:

A) computer manipulations applied to digital images.
B) creation of the digital latent image.
C) chemical processing of the digital image.
D) none of the above.

Answer 3

computer manipulations applied to digital images.

Question 4

If the field of view is 500 mm and the matrix is 1024,what are the pixel dimensions?

A) 0.49 mm × 0.49 mm
B) 0.49 mm × 0. 1024 mm
C) 0.49 mm × 2.048 mm

Question 5

The number of bits that determines the amount of precision in digitizing the analog signal and the number of gray shades that can be displayed in the image is the:

A) matrix.
B) bit depth.
C) binary code.
D) analog to digital converter.

Question 6

The pixel spacing or distance measured from the center of a pixel to an adjacent pixel is called the:

A) matrix.
B) pixel pitch.
C) bit depth.
D) pixel density.

Question 7

The greater the pixel bit depth,the _________ the digitization of the analog signal,and the _________ the number of shades of gray available for image display.

A) more precise; greater
B) less precise; greater
C) more precise; lesser
D) less precise; lesser

Question 8

An MTF of 1.0 means :

A) no difference in brightness levels.
B) no difference in spatial frequency.
C) maximum difference in brightness levels.
D) A and B.
E) B and C.

Question 9

The size of a pixel is measured in:

A) millimeters.
B) inches.
C) hertz.
D) microns.

Question 10

Increasing the number of line pairs per millimeter resolved in the imaging system results in:

A) higher spatial frequency.
B) lower spatial frequency.
C) increased spatial resolution.
D) decreased spatial resolution.
E) A and C.
F) B and D.

Question 11

Which of the following results in improved spatial resolution?

A) Increased pixel density
B) Increased pixel pitch
C) Decreased pixel density
D) Decreased pixel pitch
E) A and D
F) B and C

Question 12

If the field of view is increased for a fixed matrix:

A) the pixel size is increased.
B) the pixel size is decreased.
C) the pixel size is not affected.

Question 13

The measure of the imaging system's ability to display the contrast of anatomic objects varying in size is the:

A) spatial frequency.
B) modulation transfer function.
C) maximum intensity.
D) minimum intensity.

Question 14

A combination of rows and columns (array)of pixels is called a:

A) matrix.
B) field of view.
C) voxel.
D) liquid crystal display.

Question 15

Digital image quality is improved with:

A) larger size matrix.
B) larger size pixels.
C) smaller size matrix.
D) smaller size pixels.
E) A and B.
F) A and D.
G) C and D.

Question 16

If the matrix is increased for a given FOV:

A) spatial resolution is increased.
B) spatial resolution is decreased.
C) spatial resolution is not affected.

Question 17

The pixel bit depth determines the image's:

A) brightness.
B) contrast.
C) spatial resolution.
D) contrast resolution.

Question 18

A larger bit depth:

A) increases contrast resolution.
B) decreases contrast resolution.
C) has no effect on contrast resolution.
D) increases the pixel density.

Question 19

The number of pixels per unit area is called the:

A) matrix.
B) pixel pitch.
C) bit depth.
D) pixel density.

Question 20

A larger bit depth:

A) results in increased spatial resolution.
B) reduces the number of shades of gray.
C) increases the number of shades of gray.
D) affects both digital and film-screen image quality.

Question 21

With CR,a higher sampling frequency results in _____________ pixel density and ____________ spatial resolution.

A) increased; increased
B) increased; decreased
C) decreased; increased
D) decreased; decreased

Question 22

The _____________ collects,amplifies,and converts visible light to an electrical signal.

A) ADC
B) PMT
C) PSP
D) PSST

Question 23

Which of the following is the sequence of events,from beginning to end,of what happens in the CR reader unit?
1)Analog electrical signal is sampled and digitized.
2)Stored energy is released as visible light.
3)PMT converts light energy to electrical signal.

A) 1, 2, 3
B) 2, 3, 1
C) 1, 3, 2
D) 2, 1, 3

Question 24

With CR,when the x-ray photons are absorbed by the phosphor,the ___________ atoms become ionized.

A) barium fluorohalide
B) tungsten
C) europium
D) silver halide

Question 25

The emission of light when stimulated by a high-intensity laser beam is:

A) luminescence.
B) photostimulable phosphor.
C) photostimulable luminescence.
D) none of the above.

Question 26

How often the analog signal is digitized is the:

A) sampling frequency.
B) sampling pitch.
C) pixel frequency.
D) pixel pitch.

Question 27

With a fixed matrix CR reader system,changing to a larger IP,for the same FOV,will result in:

A) larger pixels.
B) smaller pixels.
C) improved spatial resolution.
D) B and C.

Question 28

Which of the following is not a component of the CR IP?

A) Emulsion layer
B) Support layer
C) Phosphor layer
D) Protective layer

Question 29

With CR,a higher sampling frequency results in _____________ pixel size and ____________ spatial resolution.

A) increased; increased
B) increased; decreased
C) decreased; increased
D) decreased; decreased

Question 30

Which of the following is true concerning computed radiography imaging plates?

A) The CR cassette houses the imaging plate.
B) The radiation exiting the patient interacts with the imaging plate.
C) The photon intensities are absorbed by the phosphor.
D) All of the above.

Question 31

With CR,a higher sampling pitch results in _____________ pixel size and ____________ spatial resolution.

A) increased; increased
B) increased; decreased
C) decreased; increased
D) decreased; decreased

Question 32

With CR,trapped electrons are:

A) proportional in number to the tissue's x-ray absorption.
B) in a lower energy state.
C) released during the readout stage.
D) A and C.

Question 33

The distance between the analog points being sampled is the:

A) sampling frequency.
B) sampling pitch.
C) pixel frequency.
D) pixel pitch.

Question 34

In the CR reader unit,the IP is scanned with a(n):

A) PMT.
B) electron gun.
C) helium-neon laser beam.
D) PSP.

Question 35

Which of the following is not part of a CR reader unit?

A) Optical system
B) ADC
C) Photodetector
D) Developer tank

Question 36

This material is composed of barium fluorohalide and makes up the primary component of the CR IP.

A) Luminescence
B) Photostimulable phosphor
C) Photostimulable luminescence
D) None of the above

Question 37

The CR latent image consists of:

A) electrons trapped in the phosphor layer.
B) clumps of metallic silver in the emulsion.
C) light trapped in the phosphor layer.
D) the image as seen on the display monitor.

Question 38

What is the term generally used to describe the emission of light from a substance as the result of stimulation by radiation?

A) Luminescence
B) Phosphorescence
C) Fluorescence
D) Incandescence

Question 39

The CR phosphor layer is composed of:

A) gadolinium oxysulfide with terbium.
B) barium fluorohalide with europium.
C) lanthanum oxybromide with thulium.
D) yttrium oxysulfide with terbium.

Question 40

Pixel bit depth is determined by the:

A) ADC.
B) FOV.
C) matrix.
D) tissue type.

Question 41

Compared with film-screen detectors:

A) digital IRs have a much narrower dynamic range.
B) digital IRs have a much wider dynamic range.
C) digital IRs have no dynamic range.

Question 42

Immediately before leaving the CR reader unit,the IP is exposed to:

A) the laser light.
B) developer chemicals.
C) intense white light.
D) x-rays.

Question 43

____________ can be removed from the Bucky and is used on the tabletop or a stretcher.

A) Full panel digitizer
B) Flat-panel detector
C) Folding pixel detector
D) Failure to properly digitize

Question 44

An example of a scintillator used in an indirect conversion detector is:

A) cesium iodide.
B) gadolinium oxysulfide.
C) amorphous selenium.
D) A and B.
E) A and C.

Question 45

The higher the DQE of a system,the radiation exposure required to produce a quality image is:

A) increased.
B) decreased.
C) not effected.

Question 46

Which of the following is the sequence of events,from beginning to end,for production of a DR image using direct conversion detectors?
1)Image matrix is formed in computer.
2)Charge is briefly stored in TFT array.
3)Exit radiation is converted to electrical charge.
4)Electronic signal goes to ADC.

A) 3, 4, 1, 2
B) 4, 2, 3, 1
C) 2, 4, 3, 1
D) 3, 2, 4, 1

Question 47

_________ the SNR increases the visibility of anatomic details.

A) Increasing
B) Decreasing
C) Maintaining

Question 48

Overexposing a digital image receptor may result in a quality image,but:

A) quantum noise will be visible.
B) the SNR will be poor.
C) the ALARA principle has not been followed.
D) the system will not last as long as expected.

Question 49

The ____________ array is divided into square detector elements (DEL).

A) ADC
B) IP
C) TFT
D) SNR

Question 50

The indirect conversion detector uses:

A) a scintillator.
B) a photodetector.
C) amorphous selenium.
D) A and B.

Question 51

A method of describing the strength of the radiation exposure compared with the amount of noise apparent in the digital image is the:

A) signal-to-noise ratio.
B) contrast-to-noise ratio.
C) modulation transfer function.
D) detective quantum efficiency.

Question 52

The percentage of x-rays that have reached the detector and have been captured is the:

A) TFT array.
B) fill factor.
C) ADC.
D) quantization.

Question 53

DR imaging systems briefly store the electrical charge in the:

A) ADC.
B) TFT.
C) CRT.
D) DQE.

Question 54

A method of describing the contrast resolution compared with the amount of noise apparent in a digital image is the:

A) signal-to-noise ratio.
B) contrast-to-noise ratio.
C) modulation transfer function.
D) detective quantum efficiency.

Question 55

The DR detector array is typically located:

A) inside the cassette.
B) by the computer keyboard.
C) on top of the table.
D) where you would normally find the Bucky tray.

Question 56

Which of the following is not a component of a flat-panel detector?

A) TFT array
B) X-ray converter
C) Glass substrate
D) Phosphor layer

Question 57

Which of the following is true about the indirect conversion DR systems?

A) X-rays are converted to light then converted to electrical charges.
B) X-rays are converted to electrical charges.
C) X-rays are converted to electrical charges then converted to light.

Question 58

A high SNR means that the:

A) signal strength is high.
B) signal strength is low.
C) noise is high.
D) B and C.

Question 59

The measurement of the efficiency of an image receptor in converting the x-ray exposure it receives to a quality radiographic image is the:

A) quantum noise.
B) modulation transfer function.
C) detective quantum efficiency.
D) photostimulable luminescence.

Question 60

The ability of the detector to accurately capture the variety of photon intensities in the remnant radiation is:

A) pixel depth.
B) dynamic range.
C) ALARA.
D) pixel sensitivity.

Question 61

Diagnostic interpretation should be done at a high-resolution ___________ display monitor.

A) 1 megapixel
B) 2 megapixel
C) 5 megapixel
D) 15 megapixel

Question 62

Which of the following is not accomplished through the histogram analysis?

A) Compensation for image underexposure
B) Identification of the edges of the image
C) Manipulation of image contrast
D) Compensation for image overexposure

Question 63

_________ the CNR increases the visibility of anatomic details.

A) Increasing
B) Decreasing
C) Maintaining

Question 64

The monitor matrix size should be _________________ the image matrix size.

A) smaller than
B) at least as large as
C) five times larger than
D) ten times larger than

Question 65

The range of the histogram data set that should be included in the displayed image is determined by the:

A) LUT.
B) EI.
C) VOIs.
D) LCD.

Question 66

The DICOM GSDF is used to evaluate the:

A) display monitor.
B) film processor.
C) histogram analysis.
D) digital imaging system.

Question 67

LCD stands for:

A) liquid cathode display.
B) liquid crystal display.
C) logarithmically created digitization.
D) layered components diagram.

Question 68

In CR imaging,the ___________ of the imaging plate is scanned.

A) exposed portion
B) top half
C) bottom half
D) entire area

Question 69

Which of the following exposure indicators has an inverse relationship with exposure to the IP?

A) EI (Carestream)
B) lgM (Agfa)
C) S number (Fuji)
D) All have an inverse relationship.

Question 70

Because digital IRs have a linear exposure response and wide dynamic range,raw data images appear:

A) very bright.
B) very dark.
C) with low contrast.
D) with high contrast.

Question 71

Soft copy viewing means that the image is being viewed:

A) at a computer.
B) on a soft piece of film.
C) in a soft light environment.
D) none of the above.

Question 72

All of the data from the entire IP (including scatter outside the exposed field)may be included in the histogram analysis if:

A) only one edge of the collimated field is identified.
B) only three edges of the collimated field are identified.
C) all four edges of the collimated field are identified.
D) all of the above.

Question 73

A CRT type monitor:

A) has a fluorescent screen.
B) uses an electron gun.
C) scans in lines.
D) all of the above.

Question 74

Which of the following changes in the exposure indicator values does NOT represent a doubling of radiation exposure to the IR?

A) S number (Fuji) changing from 200 to 400
B) S number (Fuji) changing from 400 to 200
C) EI (Carestream) changing from 1200 to 1500
D) EI (Carestream) changing from 1500 to 1800

Question 75

Which of the following passes light through liquid crystals to display the image on the glass faceplate?

A) Cathode ray tube monitor
B) Liquid crystal display monitor
C) Plasma display panel monitor
D) Thin-film transistor monitor

Question 76

The histogram analysis represents the ______________ for different exposure levels.

A) intensity of exposure
B) incidence of pixels
C) exposure index
D) all of the above

Question 77

The numerical value indicating the level of radiation exposure to the digital IR is the:

A) VOI.
B) histogram.
C) exposure indicator.
D) LUT.

Question 78

A value that reflects the difference between the desired or target exposure to the IR and the actual exposure to the IR is the:

A) EI (Carestream).
B) lgM (Agfa).
C) S number (Fuji).
D) deviation index (DI).

Question 79

Based on the histogram analysis,consistent image brightness is accomplished through:

A) adjustment of window width.
B) automatic rescaling.
C) manipulation of the exposure indicator.
D) manipulation of the LUT.

Question 80

The _________ provides a method of altering the image to change the display of the digital image.

A) histogram
B) lookup table
C) exposure indicator
D) matrix