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2403 Physics > Chapter 15 Exam > Flashcards

Chapter 15 Exam Flashcards

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1
Q
  1. Which of the following is composed of cesium iodide?
    a. Conventional fluoroscopic screen
    b. Intensifier input phosphor
    c. Intensifier output phosphor
    d. Intensifier photocathode
A

b. Intensifier input phosphor

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2
Q
  1. Which of the following are negatively charges electrodes plated on the inner surface of the glass envelope of the image intensifier?
    a. Photocathode
    b. Electrostatic focusing lenses
    c. Input phosphor
    d. Output phosphor
A

b. Electrostatic focusing lenses

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3
Q
  1. Which of the following emits electrons in response to light stimulus?
    a. Conventional fluoroscopic screen
    b. Intensified input phosphor
    c. Intensified output phosphor
    d. Intensified photocathode
A

d. Intensified photocathode

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4
Q
  1. What part of the image intensifier will attract the electrons and increase their kinetic energy?
    a. Input phosphor
    b. Output phosphor
    c. Electrostatic focusing lenses
    d. Accelerating anode
A

d. Accelerating anode

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5
Q
  1. Which of the following will occur if voltage to the electrostatic focusing lenses is increased?
    a. Inversion of the image
    b. Reversal of the image
    c. Minification of the image
    d. Magnification of the image
A

d. Magnification of the image

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6
Q
  1. What portion of the TV camera tube will conduct only when illuminated?
    a. Electron gun
    b. Target layer
    c. Signal plate
    d. Face plate
A

b. Target layer

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7
Q
  1. A signal is received by the monitor from which part of the TV camera tube?
    a. Electron gun
    b. Target
    c. Signal plate
    d. Face plate
A

c. Signal plate

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8
Q
  1. Which display monitor design used nematic liquid crystals?
    a. LCD
    b. Plasma
    c. Television (CRT)
    d. These gases are not used in monitors
A

a. LCD

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9
Q
  1. Which of the following is within the spatial resolution range of a flat-panel detector?
    a. 1.0 Lp/mm
    b. 2.0 Lp/mm
    c. 3.0 Lp/mm
    d. 4.0 Lp/mm
A

c. 3.0 Lp/mm

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10
Q
  1. The maximum air kerma rate for fluoroscopy is:
    a. 2 R/min
    b. 6 R/min
    c. 10 R/min
    d. 14 R/min
A

c. 10 R/min

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11
Q
  1. The ratio of the number of light photons at the output phosphor to the number at the input phosphor equals:
    a. Brightness gain
    b. Flux gain
    c. Minification gain
    d. Magnification gain
A

b. Flux gain

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12
Q
  1. What fluoroscopic operation is defined as the number of exposures per second?
    a. Frame averaging
    b. Pulse width
    c. Pulse rate
    d. Dose rates
A

c. Pulse rate

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13
Q
  1. The ability to adjust the collimator without exposing the patient to additional radiation is known as:
    a. Frame averaging
    b. Air kerma
    c. Virtual collimation
    d. Electrostatic focusing lens
A

c. Virtual collimation

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14
Q
  1. What fluoroscopic feature defines the exposure length of time during pulsed fluoroscopy?
    a. Dose rates
    b. Pulse width
    c. Pulse rate
    d. Flux gain
A

b. Pulse width

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15
Q
  1. Which fluoroscopic feature will minimize patient radiation exposure?
    a. Frame averaging
    b. Last image hold
    c. Fluoro loop save
    d. All of the above
A

d. All of the above

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16
Q

Operational QC testing of fluoro unit

A

The radiographer may be responsible for the operational inspection of the equipment

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17
Q

Fluoro documentation patients’ record

A

Fluoro machine keeps track of everything

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18
Q

refers to the length of each pulse

A

Pulse width

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19
Q

refers to how many pulses occur per second of operation (how many exposures occur per second

A

Pulse rate

20
Q

Reduces patient dose and image noise by averaging multiple frames together, however, spatial resolution decreased

A

Frame averaging

21
Q

When operating the image intensifier in magnification mode, the voltage to the electrostatic focusing lenses is ________
This increases the ability to see _____ ______, but ________ the radiation dose to the patient.

A

increased, small structures, increases
Digital magnification and radiation dose

22
Q

Flat panel detector FOV and dynamic range

A
  • Dynamic versions of these detectors must respond in rapid sequences to create a dynamic image.
  • Have wider dynamic range, current dynamic versions are capable of up to 60 frames per second
  • Present a rectangular field providing more info
23
Q

The area of each pixel that is sensitive to x-ray detection materials
How much of each dexel can see x-rays (80%)

A

Fill factor

24
Q

Advantages of a flat panel detector

A
  • Reduce tower size, bulk, weight
  • Replace spot filming
  • Do not degrade with age, more durable
  • Have better contrast resolution, higher DQE, wider dynamic range, rectangular field, post processing options
  • Do not exhibit most image artifacts
25
Q

what is indirect-capture detector made of?

A

cesium iodide amorphous silicon

26
Q

optical lens system

A

is a series of optical lenses that focus the image from the output phosphor on the camera tube

27
Q

What does the flat panel detector replace?

A

Image intensifier

28
Q
  • A light-sensitive semiconducting device that generates an electrical charge when stimulated by light and stores this charge in a capacitor. The charge is proportional to the light intensity and is stored in rows of pixels.
  • More light-sensitive and exhibits less noise and no spatial distortion
A

CCD and CCD capacitor

29
Q

A loss of brightness around the periphery of the image

A

Vignetting

30
Q

When operated in the magnification mode, the voltage to the electrostatic focusing lenses is ________.
This _______ tightens the diameter of the electron stream, and the focal point is shifted farther from the output phosphor so that only those electrons from the center area of the input phosphor interact with the output phosphor, giving the appearance of magnification

A

increased, increase

31
Q

Magnification _______ spatial resolution

A

increases

32
Q

Magnification _______ voltage to the electrostatic focusing lenses

A

increases

33
Q

A function of the fluoro unit that maintains the overall appearance of the intensified image by automatically adjusting the kilovoltage peak (kVp), milliamperage (mA), or both

A

Automatic Brightness Control (ABC)

34
Q

Conversion factor measurement

A

An expression of the luminance at the output phosphor divided by the input exposure rate
Output phosphor illumination (cd/m^2) / input exposure rate (mR/s)

35
Q

An expression of the ability of an image intensifier tube to convert x-ray energy into light energy and increase the brightness of the image in the process

A

Brightness gain

36
Q

The reduction in the size of the output phosphor image compared with that of the input phosphor image also increases the light intensities

A

Minification gain

37
Q

Accelerating the electrons increase the light intensities at the output phosphor

A

Flux gain

38
Q

Not lenses but are negatively charged plates along the length of the image intensifier tube. They repel the electron stream, focusing it toward the small output phosphor

A

Electrostatic lenses

39
Q

Changes light rays into electrons

A

Photocathode

40
Q

Located at the neck of the image intensifier near the output phosphor. Maintains a constant potential of approximately 25 kV

A

Accelerating anode

41
Q

made of silver-activated zinc cadmium sulfide and is much smaller than the input phosphor. Located at the opposite end of the image intensifier, just beyond the accelerating anode

A

Output phosphor

42
Q

faces the patient, absorbs the remnant beam, and emits light in response

A

Input phosphor

43
Q

Luminance of original fluoroscopy units

A

It wasn’t bright so the operator had to be in a dark room while wearing adaption goggles with red lenses

44
Q

monitors that offer superior resolution and brightness over television monitors, made up of several layers

A

LCD (liquid crystal display)

45
Q

respond is rapid sequences to create a dynamic image, capable of up to 60 frames per second

A

dynamic imaging

46
Q

a process using a radiographic cassette to obtain an image, or uses a photo-spot camera

A

static imaging

47
Q

what is the magnification formula?

A

MF = full size input phosphor / selected input phosphor

2403 Physics (8 decks)

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