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Rad. Physics > Exam II > Flashcards

Exam II Flashcards

1
Q

If the distance from the source is changed from 72” to 36” and the original intensity was 200mR, what is the new intensity?

A

800 mR

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2
Q

When filament electrons enter the anode target, they interact with

A

Outer shell electrons of tungsten atoms

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3
Q

The x-axis for all emission spectra represents the

A

Energy levels of the photons

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4
Q

Increasing the kVp results in

A

An increase along the y-axis and a shift to the right along the x-axis

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5
Q

The purpose of beam filtration is to

A

Reduce patient dose.

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6
Q

During the bremsstrahlung interaction, the filament electron

A

Is attracted to the nucleus not absorbed

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7
Q

Changing from a high frequency generator to a single phase generator in the x-ray emission spectrum

A

Both: changes along the x-axis and y-axis

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8
Q

True or False:
When the kVp is changed from 60 to 120, the discrete line on the x-ray emission spectrum shifts to the right.

A

False

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9
Q

If a filament electron leaves the tungsten atom with 15 keV of energy and the brems photon produced is 65 keV, how much energy did the incoming filament electron have?

A

80 keV.

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10
Q

Adding filtration in the path of the beam results in the x-ray emission spectrum

A

Both: Changing along the x-axis and the y-axis

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11
Q

The energy of the characteristic x-ray photon depends on:

A

All of these.
The binding energy of the inner shell electron, the energy level of the filament electron, and the shell of the electron that is dropping into the vacancy.

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12
Q

One HVL reduces the intensity of the x-ray beam to ______ of its original

A

One half

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13
Q

Changes along the x-axis of the x-ray emission spectrum reflect changes in ___ of the x-ray beam

A

Quality

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14
Q

True or False

HVL is described as a certain amount of tungsten or its equivalent that will reduce beam intensity by one half.

A

False

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15
Q

The x-ray emission spectrum is a graphic illustration of

A

Characteristic radiation and bremsstrahlung radiation.

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16
Q

The process of a series of outer-shell electrons filling inner-shell vacancies right after the other is called

A

Characteristic cascade

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17
Q

Changing the _____ results in changes to the x-axis, y-axis, and location of the discrete line of the x-ray emission spectrum

A

Target material

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18
Q

If kVp is doubled, the quantity of radiation increases by a factor of

A

4

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19
Q

A continuous emission spectrum is a graphic representation of

A

Bremsstrahlung radiation

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20
Q

Filtration placed in the path of the x-ray beam

A

Absorbs low-energy photons.

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21
Q

If filament electron enters the tungsten atom with 80 keV of energy and leaves the atom with 75 keV energy:

A

The filament electron traveled very far from the nucleus

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22
Q

With a 75 kVp exposure,the peak of the curve on the continuous emission spectrum is approximately

A

25 keV

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23
Q

The y-axis for all emission spectra represents the

A

Number of photons

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24
Q

If the distance is doubled, the quantity of radiation reaching a specific area is ____ the original

A

One fourth (1/4)

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25
Q

A filament electron removes a k shell electron and an M shell electrons fills the vacancy. The k shell binding energy is 69.5 keV and the M shell binding energy is 2.8 keV. What is the energy of the k-characteristic photon produced?

A

66.7 keV

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26
Q

To double the beam quantity

A

Double the mAs

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27
Q

It is recommended that kVp not be used to control beam quantity because

A

All of the above.
It affects scatter production
It affects penetrability of a beam
it is less predictable in how changing the kVp affects the image

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28
Q

The beam that is found leaving the collimator and exposes the patient is called the

A

Primary beam

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29
Q

Beam quality refers to

A

The energy level of the radiation

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30
Q

A higher energy beam is said to be a

A

Hard beam

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31
Q

Placing filtration in the path of the beam results in

A

A harder beam

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32
Q

During x-ray production the electrons penetrate the target approximately

A

0.5mm

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33
Q

To increase the quantity of radiation by adjusting the kVp to the same level as doubling the mAs, increase kVp by a factor of

A

15%

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34
Q

Half value layer (HVL) is used to measure

A

Beam quality

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35
Q

X-rays are produced by

A

Characteristic and bremsstrahlung interations

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36
Q

The remnant radiation that have an interaction with an anatomic structure is

A

Scattered radiation

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37
Q

If the intensity of the beam is 900 mR at a distance of 21 inches, what does the distance need to be for the intensity to measure 100mR?

A

63”

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38
Q

The discrete emission spectrum typically displays

A

Both K and L characteristic photon energies

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39
Q

Which of the following factors affect beam quantity?

A

All

-kVp
-Distance
-Filtration

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40
Q

Which of the following results in the equivalent of doubling the mAs if the original kVp is 80?

A

92 kVp

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41
Q

True or False:

A 65 keV filament electron is not able to produce characteristic radiation

A

True.

To produce characteristic radiation, the electron’s energy must be greater than the orbital electron’s binding energy.

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42
Q

The x-ray beam that leaves the patient to expose the IR is called the

A

Remnant beam

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43
Q

The remnant radiation that did not interact with any anatomic structure is

A

Transmitted radiation

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44
Q

L-characteristic and higher photon energies are not usually displayed on a discrete emission spectrum because

A

The energies of the photons are too low for image formation

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45
Q

True or False
The probability of Compton scattering depends on the atomic number of the atom.

A
46
Q

The x-ray photons that are produced as a result of a characteristic cascade during a Compton interaction

A

are characteristic x-ray photons.

47
Q

Secondary photons produced during a Compton interaction

A

contribute to patient dose.

48
Q

The Compton electron

A

has enough energy to produce further interactions.

49
Q

For photoelectric interactions to occur, the energy of the incident photon

A

may be the same or greater than the binding energy of an inner-shell electron.

50
Q

True or false
Deoxyribonucleic acid (DNA) is the most sensitive human cell molecule.

A

True

51
Q

After ejection from the atom’s nucleus, when the positron interacts with an electron

A

all of these.

52
Q

The fog seen on the radiographic image is the result of

A

Compton interactions

53
Q

Compton scattering typically occurs with x-ray photons in the energy range of

A

20-40

54
Q

The Compton scatter photon

A

may exit the patient as part of the remnant radiation and has enough energy to produce further interactions.

55
Q

Pair production

A

never occurs during radiographic procedures

56
Q

A positron is

A

a positively charged electron.

57
Q

Compton scattering results in

A

All of these

58
Q

The energy of the photoelectron is the least as a result of a photoelectric interaction in

A

Bone

59
Q

True or False
Irradiation of water can create harmful free radicals that then indirectly damage molecules and cells.

A

True

60
Q

True or False
The photoelectric interaction and Compton interaction can both result in a characteristic cascade, producing characteristic radiation.

A

True

61
Q

True or False
All Compton scatter photons travel in the direction of the image receptor.

A

False

62
Q

The greater the absorption of radiation

A

the greater the patient dose.

63
Q

The energy of the photoelectron is equal to

A

the energy of the incident photon minus the binding energy of the orbital electron.

64
Q

When it does interact with the image receptor, the Compton scatter photon contributes no useful information because

A

it has changed direction.

65
Q

The primary source of radiation exposure to the radiographer who is in the room during an exposure is

A

from scatter from the patient.

66
Q

With Compton scattering, the incident photon

A

loses up to one third of its energy.

67
Q

True or False
Potential biological damage can occur as a result of a Compton interaction because of the ionization of atoms.

A

True

68
Q

Compton scattering involves the x-ray photon

A

removing a middle- or outer-shell electron.

69
Q

The greater the angle of deflection of a Compton scatter photon:

A

the lower the energy of the photon.

70
Q

True or False
The probability of Compton scattering depends on the atomic number of the atom.

A

False

71
Q

Pair production occurs when the incident photon interacts with

A

the nucleus of the atom

72
Q

Compton scattering typically occurs with

A

moderate-energy photons.

73
Q

Photodisintegration occurs when the incident photon interacts with

A

the nucleus of the atom.

74
Q

Dense material, like bone, is considered:

A

radiopaque.

75
Q

During a photoelectric interaction,

A

an inner-shell electron is ejected.

76
Q

Barium sulfate is used as a contrast agent to visualize soft tissue structures such as the stomach because it

A

has a high atomic number.

77
Q

The end product(s) of a photoelectric interaction is (are)

A

a photoelectron and an ionized atom.

78
Q

In reference to patient radiation dose, classical scatter interactions

A

slightly increase dose.

79
Q

The x-ray photon produced during classical scattering

A

is the same energy as the incident photon.

80
Q

Most classical scatter photons

A

are absorbed in the body.

81
Q

No matter which direction the Compton scatter photon goes, it retains approximately

A

two thirds of its energy.

82
Q

The major source of radiation exposure to technologists is due to

A

Compton interactions

83
Q

True or False
The more the energy of the incident x-ray photon exceeds the binding energy of the inner-shell electron, the greater the probability of a photoelectric interaction.

A

False

84
Q

For photodisintegration to occur, the incident photon must have an energy level of at least

A

10 mev

85
Q

What is produced as a result of pair production, a(n)

A

positron and electron only.

86
Q

Protective apparel is often made of lead because it

A

has a high atomic number

87
Q

To produce a radiographic image that represents anatomy, there must be

A

All of these

88
Q

True or False
Without differential absorption, the image would be a single shade of gray.

A

True

89
Q

Photodisintegration interactions

A

never occur during radiographic procedures.

90
Q

If a middle-shell electron is removed during a Compton interaction

A

All of these

91
Q

Coherent scattering involves

A

an x-ray photon with low energy.

92
Q

To minimize occupational exposure, the technologist should

A

wear protective apparel (lead aprons, gloves, etc.) when in the room during imaging.

93
Q

Reducing the amount of Compton scattering

A

all of these.

94
Q

True or False
The probability of a photoelectric interaction depends on the atomic number of the atom.

A

True

95
Q

Air is considered

A

Radiolucent

96
Q

Following absorption of the incident photon in the atoms nucleus, a photodisintegration interaction may result in

A

neutrons and protons being ejected from the nucleus

97
Q

Photoelectric interactions

A

Contribute significantly to patient dose

98
Q

true or false
the higher the atomic number of an atom, the greater the probability of a photoelectric interaction

A

true

99
Q

radiation interacting with air is more likely to be ___ resulting in that area of the image being darker

A

transmitted

100
Q

photoelectric interactions are more likely to occur in

A

bone

101
Q

the probability of Compton scattering depends on the energy level of the incident x-ray photon

A

true

102
Q

after a photoelectric interaction, the incident photons

A

loses all of its energy and no longer exists

103
Q

classical interactions are also known as

A

thompson and coherent scattering

104
Q

the x-ray photon being produced during classical scattering

A

travels in a different direction than the incoming photon

105
Q

excessive absorption is the result of

A

using a kvp too low for the examination

106
Q

the effect of classical scatter interactions on image quality

A

is minimal

107
Q

secondary x-ray photons are the result of

A

Compton interactions and photoelectric interactions

108
Q

pair production requires an x-ray photon with an energy of at least

A

1.02 MeV

109
Q

true or false
the probability of a photoelectric interaction depends on the energy level of the incident x-ray photon

A

true

110
Q

The greater the absorption of radiation

A

the greater the patient dose.

Rad. Physics (1 decks)

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