Review Exam 1 Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Mode of decay when high n/p+ ratio

A

B-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Mode of decay when too many neutrons

A

B-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mode of decay when too many p+

A

Beta +/Positron emission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Most likely mode of decay for heavier elements

A

Alpha

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Mode of decay for PET

A

Positron Emission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mode of decay that can result in characteristic or Auger e-

A

Electron capture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Isotope

A

same # of p+, diff # neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Isotone

A

Same # of neutrons, diff # p+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Isobar

A

Same # nucleons (both), diff p+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Formula for # of e- in a shell

A

2n^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

speed of light

A

3 x 10^8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The penetrability of the beam is the definition of?
Expressed by what 2 concepts?

A

Beam quality.
HVL or kVp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The # of photons

A

Quantity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Space charge effect

A

Space-charge effect creates a cloud of electrons caused by the electrons repelling each other, rather than the free flow of electrons. Can cause reduced beam output.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Positive side of x-ray tube

A

anode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

negative side of x-ray tube

A

Cathode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does cathode do?

A

Has tungsten filament that emits e- when heated (thermionic emission occurs here)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does anode do?

A

Contains tungsten target; electrons hit target to produce x-rays.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Contains tungsten target; electrons hit target to produce x-rays.

A

Anode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Has tungsten filament that emits e- when heated (thermionic emission occurs here)

A

Cathode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

3 reasons tungsten is chosen for the target?

A
  1. High Z (high production efficiency)
  2. High melting point
  3. Dissipates heat (prevents overheating)??
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Explain anode-heel effect

A

The heel attenuates more electrons, so intensity on the heel side is decreased. The greater the target angle, the greater the attenuation of the beam.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Avg energy of ployenergetic beam is?

A

1/3 max photon energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Occurs when a particle (charged)
such as an electron, proton or alpha particle collides with matter to produce a charged particle.

A

Direct ionization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Occurs when an uncharged particle
or radiation such as a photon or neutron liberate a directly ionizing particle when they interact with matter.

A

Indirect ionization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Atoms of the target become ionized or excited

A

Direct action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Radiation interacts with other atoms to produce free radicals that then do the damage to critical targets.

A

Indirect action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Interaction dominant in tx range?

A

Compton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Interaction dominant in dx range?

A

Photoelectric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Probability of brems:

A

Z^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Z of tungsten

A

74

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Beam flatness is measured where?

A

10 cm depth in water, but only middle 80% of beam bc of penumbra.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Beam flatness is?

A

of photons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Beam flatness is quantity or quality?

A

Quantity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How does filtration affect the quality of the beam?

A

it hardens the beam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How does filtration affect the quantity of the beam?

A

Reduces it by 4x (to 1/4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What does beam flatness look like deeper than 10 cm?

A

middle hump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does beam flatness look like more shallow than 10 cm?

A

lateral horns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Linac Part: changes direction of horizontal beam to vertical

A

Bending Magnet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Linac Part: copper “pipe” held under high vacuum to remove air molecules, where e- are accelerated

A

Waveguide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Energy range for Grenz:

A

10-20kVp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Energy range for Contact therapy:

A

40-50kVp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Energy range for Superficial

A

50-150kVp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Energy range for orthovoltage

A

150-500kVp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Energy range for supervoltge

A

500kVp – 1MV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is the input electron energy from the electron gun?

A

50 keV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Photon interaction most likely with High Z:

A

Coherent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Photoelectric Z and/or E:

A

Z^3/E^3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Pair production Z and/or E:

A

Z^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Comp Z and/or E:

A

Ind of Z, depends on e-density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Coherent energy range:

A

<10KeV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Photelectric energy range:

A

60-90 KeV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Compton energy range:

A

25 KeV – 10 MeV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Pair production energy range:

A

> 1.02 MeV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Pneumonic for photon interaction:

A

CoPhoComPair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Coherent - inner or outer shell e-?

A

outer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Photelectric - inner or outer shell e-?

A

inner

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Compton - inner or outer shell e-?

A

outer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Pair Production - inner or outer shell e-?

A

inner

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What happens to penumbra if you increase SSD?

A

it increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Klystron vs magnetron:
Cheaper
Shorter lifespan

A

Magnetron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Klystron vs magnetron:
Higher energy
More stable
More expensive

A

Klystron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Klystron vs magnetron:
More common in high energy Linacs

A

Klystron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What linear accelerator component sets the dose rate?

A

Modulator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What components in the linear accelerator treatment head change between electron and photon mode? Photon mode

A

Target and flattening filter is in the carousel when it is in photon mode.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What components in the linear accelerator treatment head change between electron and photon mode? Electron mode

A

Target is removed and scattering foil is put in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Klystron vs magnetron - which one amplifies microwaves?

A

Klystron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Klystron vs magnetron - which one generates microwaves?

A

magnetron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What machine component injects pulsed electrons to waveguide?

A

Electron gun

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Variation of dose in comparison to CAX dose at depth of 10cm is the definition for?

A

Flatness

70
Q

The amount of time to deliver 1 cGy, with a 10x10 cm FS, to a specified depth (usually DMAX), at a distance of 100cm away is the definition of?

A

MU

71
Q

The photon interacts with an atom and ejects on of the (inner) orbital electrons. The photon gives 100% of its energy to the ejected electron.

A

Photoelectric Effect

72
Q

Auger and characteristic x-rays can occur with which photon interaction?

A

Photelectric

73
Q

An incoming photon hits an outer orbital electron & not all energy is transferred. This results in an ejected electron and a weaker photon.

A

Compton

74
Q

Annihilation reaction can happen after?

A

Pair production

75
Q

An incoming photon interacts with the nucleus and gives up all of its energy in creating a positron and negatron.

A

Pair production

76
Q

Modes of decay: Combination of two lighter nuclei

A

Nuclear Fusion

77
Q

Modes of decay: Nucleus splits into two

A

Nuclear Fission

78
Q

1 J/kg = ___ Rads = ___ Gy

A

100, 1

79
Q

1 Gy = ___ cGy

A

100

80
Q

1cGy = ___ rad = ___ Gy

A

1, 0.01

81
Q

A photon passes near an electron and sets it into an oscillation. The oscillating e- then re-radiates the energy at the same frequency as
the incident photon.

A

Coherent scatter

82
Q
A
83
Q
A
84
Q

MU: The amount of time to deliver ___, with a __ FS, to a specified depth (usually ___), at a distance of ___ away is the definition of?

A

1 cGy, 10x10 cm, DMAX, 100cm

85
Q

What is meant by “good geometry”?

A

Put the detector where no scatter will be measured.

86
Q

To measure beam flatness, all points must be within __?

A

3%

87
Q

A voltage rectifier does what?

A

Prevents backflow (e- can only go in one direction)

87
Q

When the beam goes through the mirror it is what type of filtration?

A

Inherent

87
Q

Describe the difference in HVLs for monoenergitc beams vs polyenergetic beams:
Why?

A

Monoenergetic - all HVLs are the same thickness
Polyenergetic - Each subsequent HVL will be thicker due to beam hardening

88
Q

How do you calculate the binding energy for the L or M-shell?

A

E = E (k-shell) - E (L or M-shell)

89
Q

How does kVp affect output?

A

squared relationship

90
Q

How mA or mAs affect output?

A

Directly proportional relationship

91
Q

What does a flattening filter do to the avg energy of the beam? Why?

A

Increases it due to beam hardening

92
Q

Flattening filter filters out __ photons?

A

low energy

93
Q

Brems produces a monoenergetic or polyenergetic beam?

A

polyenergetic

94
Q

Characteristic produces a monoenergetic or polyenergetic beam?

A

monoenergetic

95
Q

Why doesn’t this graph start out at 0?

A

The beam has been hardened, so all low energy photons have been filtered out already.

96
Q

Calculate the avg energy of this graph.

A

150keV x 1/3 = 50 keV

97
Q

Explain what the peaks are.

A

Characteristic x-ray of different atoms that are emitted that occur when the electron drops from one orbital to the other after an e- has been ejected from that orbital.
The energy will always be the same for the same atom. The energy is “characteristic” of each atom.

98
Q

A high speed electron passes near a
nucleus and is deflected from its pass after being acted upon by Coulomb forces. They lose energy, slow down and propagates the
energy through space.

A

Brems

99
Q

“braking radiation”

A

Brems

100
Q

Brems or Characteristic: Part or all of the electron’s energy may be given off

A

Brems

101
Q

Electron can engage in multiple ___ interactions

A

Bremsstrahlung

102
Q

Brems or Characteristic?

A

Brems

103
Q

Brems or Characteristic: Direction of beam depends on energy.

A

Breams

104
Q

The higher the energy of a brems beam, the ___ (direction) beam is.

A

more forward

105
Q

Probability of brems varies with __ of the __.

A

Z^2, target

106
Q

What determines the energy of the Brem beam?

A

How close it gets to nucleus and how much it makes it change its path

107
Q

Brems or Characteristic?

A

Brems

108
Q

An electron interacts with an atom by ejecting an orbital electron which leaves the atom ionized.

A

Characteristic

109
Q

Describe how a characteristic x-ray occurs: (4 steps)

A
  1. An electron interacts with an atom by ejecting an orbital electron which leaves the atom ionized.
  2. A vacancy is created and an outer orbital electron will fall down to a
    closer orbital
  3. When an electron moves down there is an energy potential, which results in x-rays.
  4. Energy potential between orbital levels result in discrete (monoenergetic) energies
110
Q

Characteristic is also called?

A

Fluoroscence

111
Q
A

Characteristic

112
Q

Electron capture and ___ are competing processes?

A

Beta +

113
Q

Characteristic is favored in the __ Z range, while Auger is favored in __.

A

high, low

114
Q

Which is more likely to occur, a characteristic x-ray or an Auger e-?

A

Characteristic

115
Q

A is

A

Atomic mass #, # of nucleons

116
Q

Z is

A

Atomic #, # of p+

117
Q

Are photons directly or indirectly ionizing?

A

Indirectly

118
Q

A

Fluence

119
Q

A

Fluence rate or flux density

120
Q

Which interaction independent of Z?

A

Compton

121
Q

Identify the mode of decay:

A

Alpha

122
Q

Identify the mode of decay:

A

B-

123
Q

Identify the mode of decay:

A

B+ or positron emission

124
Q

Identify the mode of decay:

A

E- capture

125
Q

Identify the mode of decay: helium nucleus

A

Alpha

125
Q

Identify the mode of decay: 2 protons, 2 neutrons, no electrons

A

Alpha

126
Q

Identify the mode of decay:
Excess neutrons (high n/p) ratio, and it must be reduced. Done by emitting an electron.

A

B-

127
Q

Identify the mode of decay:
neutron to proton

A

B-

128
Q

Identify the mode of decay:
proton to neutron

A

B+ or e- capture

129
Q

Identify the mode of decay:
Deficiency in neutrons

A

B+

130
Q

Identify the mode of decay:
low n/p ratio

A

B+

131
Q

Identify the mode of decay:
Orbital electron gets captured by nucleus and combines with a proton, transforming into a neutron

A

E- capture

132
Q

Identify the mode of decay:
Alternative to positron decay; unstable nuclei deficient of neutrons seeks to increase n/p ratio.

A

E- capture

133
Q

Identify the mode of decay:
Characteristic x-ray or Auger e- can be emitted

A

E- capture

134
Q

Pair production can lead to ___.

A

An annihilation reaction.

135
Q

Explain the relationship between Atomic #, n/p+ ratio and stability for heavy nuclei:

A

For heavy nuclei (atomic # > 20), stable nuclei have a n/p+ ratio of 1.4 to 1 (1.4 neutrons to 1 proton)

136
Q

Explain this graph

A

For heavy nuclei (atomic # > 20), stable nuclei have a n/p+ ratio of 1.4 to 1 (1.4 neutrons to 1 proton)

137
Q

Explain the relationship between Atomic #, n/p+ ratio and stability for lighter nuclei:

A

1:1 n/p+ ratio is stable for an atomic # < 20

138
Q

When looking at an equation where decay is taking place, what defines the mode of decay?

A

The particle that is emitted from the reaction

139
Q

What is the mean life formula?

A

Ta = 1.44 (T1/2)

140
Q

What is the parent and the daughter?

A

The parent is the original and the daughter is what the parent decays into.

141
Q

What nuclear reaction is used when making radioactive isotopes? (2 names)

A

alpha, p+
fusion

142
Q

What nuclear reaction is this?

A

alpha, proton

143
Q

What particle is this?

A

Deuteron

144
Q

Nuclear reaction that occurs when high Z nuclei are bombarded by neutrons. After absorbing the neutrons, it splits into nuclei of lower Z, as well as more neutrons.

A

Fission

145
Q
A

Fission

146
Q

What are the scales used for each graph?

A

Left - linear
Right - logarithmic

147
Q

What is the decay constant (definition)?

A

Portion of atoms decaying per unit time

148
Q
A

B-

149
Q
A

B+

150
Q
A

proton

151
Q
A

neutron

152
Q
A

Alpha

153
Q

e- and positron rest mass

A

9.11 x 10^-31

154
Q

E- rest energy

A

0.511 MeV

155
Q

rest mass for p+ and neutron

A

1.675 x 10^-27

156
Q

deuteron rest mass

A

3.34 x 10^-27

157
Q

alpha rest mass

A

6.65 x 10^-27 (approx. double deuteron)

158
Q

charge?

A

-1

159
Q

charge?

A

+1

160
Q

charge?

A

+1

161
Q

charge?

A

0

162
Q

charge?

A

+1

163
Q

charge?

A

+2

164
Q

The process by which an unstable nucleus/atom attempts to become stable. This results in emitting radiation (usually a particle) and the transformation of the unstable atom into a different more stable atom.

A

Radioactive decay

165
Q

What linac component is shown?

A

Klystron

166
Q

What linac component is shown?

A

Magnetron

167
Q

What linac component is shown?

A

Klystron

168
Q

Explain this graph.

A

Air KERMA is higher in the buildup region. Absorbed dose is higher after the buildup region due to also measuring backscatter.

169
Q

2 modes of decay that are competing processes:

A

B+ and electron capture