Deck 12: Digital Imaging

Question 1

With digital imaging, using twice the needed mAs will result in an image with _____ density/brightness and _____ patient exposure.

A) appropriate, excessive
B) excessive, excessive
C) excessive, appropriate
D) appropriate, appropriate

Answer 1

appropriate, excessive

Question 2

The resolution capability of the computed radiography image is approximately _____ lp/mm.

A) 2.5-5
B) 6-10
C) 12.5
D) 15

Answer 2

2.5-5

Question 3

What is the name of an image constructed from numerical information?

A) Analog image
B) Matrix image
C) Digital image
D) Subtraction image

Answer 3

Digital image

Question 4

What serves the same purpose in conventional radiography as the imaging plate used in computed radiography?

A) Grid
B) Cassette
C) Film
D) View box

Question 5

What is the device that changes into digital data the electrical signal created from the light released from the CR imaging plate?

A) Laser
B) Photomultiplier tube
C) Analog-to-digital converter
D) CRT

Question 6

When the image matrix size is increased, resulting in a decreased pixel size, what happens to spatial resolution?

A) It increases.
B) It decreases.
C) There is no change.

Question 7

_____ is the postprocessing technique that improves the visibility of small and high-contrast structures.

A) Contrast enhancement
B) Edge enhancement
C) Subtraction
D) Smoothing

Question 8

What type of laser is used to release the energy stored in the CR phosphor?

A) Neon-helium
B) Argon
C) Krypton
D) Fluorohalide

Question 9

Subtraction, contrast enhancement, and edge enhancement are known as:

A) preprocessing techniques.
B) postprocessing techniques.
C) darkroom techniques.
D) analog compilation.

Question 10

Before being reused, the imaging plate is:

A) exposed to an intense light.
B) immersed in fixer solution.
C) recoated with europium.
D) cleaned with a soft cloth.

Question 11

What is the technique used to remove superimposed structures to improve the visibility of anatomic structures?

A) Contrast enhancement
B) Edge enhancement
C) Subtraction
D) Reversal

Question 12

What is the display of the digital image that occurs in a series of rows and columns called?

A) Voxel
B) Pixel
C) Raster
D) Matrix

Question 13

Which imaging method(s) is/are difficult to use for mobile radiography?

A) Film-screen
B) CR
C) DR
D) b and c

Question 14

Which imaging method(s) require(s) the shortest time from exposure to image viewing?

A) Film-screen
B) CR
C) DR
D) a and b

Question 15

What is the graphical display of the pixel values during digital radiography known as?

A) Matrix
B) Histogram
C) Pixel
D) Voxel

Question 16

The basic unit of information in a computer is a(n):

A) bit.
B) byte.
C) word.
D) algorithm.

Question 17

What is the matrix of the digital image composed of?

A) Voxels
B) Pixels
C) Grains
D) Solutes

Question 18

Where is the latent image in computed radiography formed?

A) In the CRT screen
B) In the photostimulable phosphor
C) In the photomultiplier tube
D) In the analog-to-digital converter

Question 19

What are the mathematical calculations used for image construction of specific examinations called?

A) Interpolations
B) Algorithms
C) Extrapolations
D) Logarithms

Question 20

_____ is the postprocessing technique that suppresses image noise.

A) Contrast enhancement
B) Edge enhancement
C) Subtraction
D) Smoothing

Question 21

Which one of the following digital systems would have the best image quality?

A) 8 bit
B) 12 bit
C) 16 bit
D) 32 bit

Question 22

Image noise in digital imaging is primarily a result of:

A) quantum mottle.
B) low dynamic range.
C) wide window width.
D) postprocessing image enhancement.

Question 23

Which component of the digital image corresponds to contrast on the radiographic image?

A) Sensitometric curve
B) Window level
C) Window width
D) Image reversal

Question 24

The range of exposure intensities an image receptor can accurately detect determines its:

A) dynamic range.
B) matrix size.
C) histogram.
D) window width.

Question 25

Which of the following systems is NOT associated with direct digital radiography (DR)?

A) Flat panel digital
B) Charge-coupled device
C) Indirect conversion detector
D) Computed radiography

Question 26

How many lines would an ideal video monitor for digital radiography have?

A) 525
B) 1024
C) 1050
D) 2000

Question 27

The x-ray beam exiting the patient has the capability of producing over _____ shades of gray.

A) 32
B) 256
C) 512
D) 1000

Question 28

If a digital image is produced using one half of the appropriate mAs, the image will have:

A) appropriate density/brightness and quantum mottle.
B) insufficient density/brightness and quantum mottle.
C) appropriate density/brightness and no quantum mottle.
D) insufficient density/brightness and no quantum mottle.

Question 29

As compared to CR, a disadvantage of direct digital radiography is:

A) increased image processing time.
B) lower dynamic range.
C) incompatibility with existing equipment.
D) increased spatial resolution.

Question 30

Increasing the number of pixels in the image matrix will increase:

A) dynamic range.
B) shades of gray.
C) image brightness.
D) spatial resolution.

Question 31

The density/brightness of the digital image may be manipulated by changing the:

A) window width.
B) window level.
C) matrix size.
D) detective quantum efficiency.

Question 32

The _____ provides a method of processing digital images in order to change the density and contrast displayed.

A) matrix
B) lookup table
C) histogram
D) charge-coupled device

Question 33

_____ convert(s) conventional radiographs to digital images.

A) Charge-coupled devices
B) A film digitizer
C) Computed radiography
D) Digital fluoroscopy

Question 34

Which of the following digital imaging systems uses a photostimulable phosphor?

A) Digital fluoroscopy
B) Computed radiography
C) Direct conversion DR
D) Charge-coupled device

Question 35

Which factor sets the midpoint of the densities visible on the CRT?

A) Sensitometric curve
B) Window level
C) Window width
D) Image reversal

Question 36

Which imaging method(s) has/have the greatest spatial resolution?

A) Film-screen
B) CR
C) DR
D) a and c

Question 37

_____ is the computer standard for medical information and _____ is the communication standard for medical imaging.

A) HIS, RIS
B) DICOM, HL7
C) RIS, HIS
D) HL7, DICOM

Question 38

Which of the following matrix sizes would produce the best image quality?

A) 64 ´ 64
B) 256 ´ 256
C) 1024 ´ 1024
D) 2048 ´ 2048

Question 39

A significant advantage of digital compared to film-screen radiography is:

A) reduced patient exposure.
B) latent image formation.
C) spatial resolution.
D) postprocessing image enhancement.

Question 40

The pixel bit depth determines the amount of shades of gray the system is capable of displaying on the digital image.