NHR Atomic/Nucelar Structure From 2nd Ed MedDos Cert Study Guide By Rajan Flashcards
(221 cards)
1
Q
One atomic mass unit is equal to:
A
1.66 x 10^-27kg
From Review of Medical Dosimetry Book by William Amestoy
2
Q
What is the conversion factor from MeV/c2
A
931
From Review of Medical Dosimetry Book by William Amestoy
3
Q
What is the number of charge of a proton?
A
+1
From Review of Medical Dosimetry Book by William Amestoy
4
Q
The nucleus of an atom is composed of_____.
A
Protons and Neutrons
From Review of Medical Dosimetry Book by William Amestoy
5
Q
What is the force that binds electrons to the atom?
A
Electromagnetic force
From Review of Medical Dosimetry Book by William Amestoy
6
Q
The energy needed to remove an electron from the shell is called_____.
A
Binding energy
From Review of Medical Dosimetry Book by William Amestoy
7
Q
Electron binding energy increases _____.
A
In the K shell compared with N shell; is proportional to Z2; with increasing charge of the nucleus.
From Review of Medical Dosimetry Book by William Amestoy
8
Q
The chemical properties of an atom are determined by:
A
Valence electrons
From Review of Medical Dosimetry Book by William Amestoy
9
Q
The maximum number of electrons that can occupy a specific energy level is determined using the formula
A
2n2
From Review of Medical Dosimetry Book by William Amestoy
10
Q
What is the maximum number of electrons that can hold in L shell?
A
8
From Review of Medical Dosimetry Book by William Amestoy
11
Q
The atoms are designated by atomic symbols; the symbol A represents _____.
A
Mass number and number of protons and neutrons
From Review of Medical Dosimetry Book by William Amestoy
12
Q
In a neutral atom, the number of electrons is equal to _____.
A
Atomic number
From Review of Medical Dosimetry Book by William Amestoy
13
Q
The number of neutrons in an atom is equal to _____.
A
A - Z
From Review of Medical Dosimetry Book by William Amestoy
14
Q
In chronological order, identify the number of electrons, number of protons, number of neutrons, it’s mass number, atomic number, and number of nucleons in the following element Gold:
A
79, 79, 118, 197, 79, 197
From Review of Medical Dosimetry Book by William Amestoy
15
Q
The rest mass of an electron (MeV/c 2) is equal to:
A
0.511
From Review of Medical Dosimetry Book by William Amestoy
16
Q
A transition is said to have taken place on an atom when_____.
A. An electron is removed from an atom
B. All electrons are in the lowest allowable energy levels
C. An electron moves from its original shell to another
D. Electrons are attracted by the nucleus
A
C. An electron moves from its original shell to another
From Review of Medical Dosimetry Book by William Amestoy
17
Q
What is the maximum number of electrons allowed in M shell?
A
18
From Review of Medical Dosimetry Book by William Amestoy
18
Q
An atom which is ionized and loses an electron is called a/an _____.
A
Positive ion
From Review of Medical Dosimetry Book by William Amestoy
19
Q
Atoms who have nuclei with the same number of protons but different number of neutrons are called _____.
A
Isotopes
From Review of Medical Dosimetry Book by William Amestoy
20
Q
This is a _____.
A
Isotone
From Review of Medical Dosimetry Book by William Amestoy
21
Q
True or False: An alpha particle is identical to a helium nucleus with a mass number of 4 and an electrostatic charge of +2.
A
True
22
Q
True or False: Alpha particles are usually emitted by low-Z radioactive elements during radioactive decay.
A
False
23
Q
True or False: Alpha emission changes the identity of the radionuclide.
A
True
24
Q
True or False: Ra^226 is an alpha emitter.
A
True
25
True or False: Co^60 is an alpha emitter.
False
26
True or False: A beta particle is an electron emitted by the atomic nucleus during a radioactive decay.
True
27
True or False: Co^60 is a beta emitter.
True
28
True or False: Ir^192 is a beta emitter.
True
29
True or False: Emission of beta changes the identity of the radionuclide.
True
30
True or False: A positron is a positively charged particle but identical to an electron in all other respects.
True
Note: the reference says they are practically identical, which to me means it can be argued to be False
31
True or False: Beta decay is usually associated with proton rich radionuclides.
False
32
True or False: Positron decay is usually associated with neutron rich radionuclides.
False
33
True or False: Emission of gamma radiation does not change the identity of the radionuclide.
True
34
True or False: Gamma usually follows beta particle emission in radioactive decay.
True
35
True or False: There are no pure beta emitters.
False
36
True or False: There are no pure gamma emitters.
False
37
True or False: Electron capture usually occurs in high-Z radioactive elements.
True
38
True or False: Electron capture and beta emission are competing modes of decay.
False
39
True or False: Beta particles emitted in radioactive decay are monoenergetic.
False
40
True or False: A neutrino is a particle of negligible mass and zero charge postulated to account for the nonconservation of energy during beta decay.
True
41
True or False: A neutrino is easy to detect.
False
42
True or False: Mass is conserved in radioactive decay.
True
43
Rn^222 is a _____.
Alpha emitter
44
P^32 is a _____.
Pure beta emitter
45
Ni^59 is a _____.
Electron capture radionuclide
46
Sr^90 is a _____.
Beta emitter
47
I^125 is a _____.
Electron capture radionuclide
48
1.17 and 1.33 MeV gammas is _____.
Co^60
49
0.662 MeV gamma is a _____.
Cs^137
50
Several gammas of mean energy around 400 keV is _____.
Ir^192
51
Several gammas of mean energy around 0.8 MeV is _____.
Rn^222
52
Mean energy 28 keV is _____.
I^125
53
What is the half life for Ra^226?
1626 years
54
What is the half life for Cs^137?
30 years
55
What is the half life of Ir^192
74 days
56
What is the half life of Co^60?
5.26 years
57
What is the half life of I^125?
59.6 days
58
What is the mean life of Ir^192 source is give by _____ days.
106.5
59
After two half lives, the initial activity of a given radioisotope would have reduced to _____.
One fourth of
60
The mean life of a radioactive source is given by _____.
61
The SI unit of activity is the _____.
Becquerel (Bq)
62
One becquerel (Bq) corresponds to _____ nuclear transformations/second.
1
63
One curie corresponds to _____.
37 GBq
64
Isomeric transition is characterized by _____.
No change in the atomic or mass number
65
The SI unit of radioactivity is the _____.
Becquerel (Bq)
66
The half life of a free neutron is _____.
10.2 minutes
67
What are true statements regarding the becquerel?
It is an SI unit for activity.
One Bq = 1 nuclear transformation per second
One Bq = (3.7 x 1010>)-1 Ci
It is named in honor of Henri Becquerel
68
Radionuclides are produced by irradiating the element in _____.
A nuclear reactor
A Linac
A cyclotron
69
The Cs^137 radionuclide is _____.
A byproduct of fission in a reactor and hence is extracted from the spent fuel elements
70
_____ nuclides have the same number of neutrons.
Isotones
71
_____ nuclides have the same number of protons.
Isotopes
72
_____ nuclides have the same mass number.
Isobars
73
_____ nuclides have same Z, A but existing in different energy states.
Isomers
74
The radioactive isotopes produced in a nuclear reactor _____.
Is neutron rich and decays emitting β- particles
75
This isotope has _____.
Has 77 protons
Has 115 neutrons
76
A nuclides (Z, A) may transform into a nuclides (Z-1, A) by the emission of _____.
77
Positron emission occurs in radionuclides that have an excess of _____.
Protons
78
Of the following radionuclides, _____ are produced in accelerators.
79
This change in atomic number represents: Z Z+1
β-
80
This change in atomic number represents: Z Z
Isomersim
81
This change in atomic number represents: Z Z-1
Electron Capture
β+
82
This change in atomic number represents: Z Z-2
α
83
Method of radionuclide productivity: produced in a reactor by irradiating a stable element.
Ir^192
84
Method of productivity: produced in a cyclotron.
Co^57
85
Method of productivity: naturally occurring.
Ra^226
86
Method of productivity: Eluted from a generator.
Tc^99m
87
Method of productivity: separated from spent fuel element
I^131
88
True or False regarding positron emission: each positron emission is accompanied by a neutrino.
True
89
True or False regarding positron emission: a minimum of 1.02 MeV equivalent mass difference must exist between the parent and daughter atoms.
True
90
True or False regarding positron emission: it is followed by two annihilation photons of energy 0.511 MeV each.
True
91
True or False regarding positron emission: positrons are monoenergetic.
False
92
True or False regarding electron capture (EC): it is a competing mode from which positron decay.
True
93
True or False regarding electron capture (EC): when positron decay is energetically not possible, only EC can occur.
True
94
True or False regarding electron capture (EC): it results in characteristic x-ray emission.
True
95
True or False regarding electron capture (EC): it results in Auger electrons emission.
True
96
True or False regarding electron capture (EC): it results in Auger electrons emission.
True
97
True or False regarding electron capture (EC): it results in the emission of a neutrino.
True
98
Characteristic x-rays are emitted following _____.
Internal conversion
Electron capture
99
True or False - A radionuclide decaying by internal conversion emits: betas.
False
100
True or False - A radionuclide decaying by internal conversion emits: gammas.
True
101
True or False - A radionuclide decaying by internal conversion emits: characteristic x-rays.
True
102
True or False - A radionuclide decaying by internal conversion emits: Auger electrons.
True
103
True or False - During internal conversion: a beta is emitted.
False
104
True or False - During internal conversion: there is no change in Z or A.
True
105
True or False - During internal conversion: L and M shell electrons may also be emitted.
True
106
True or False - During internal conversion: the shell electrons are ejected by the gamma ray emitted in the isomeric transition.
False
107
True or False: X-rays are produced by decelerating high speed electrons in a target.
True
108
True or False: the mechanism of x-ray production is the same in a kV x-ray unit and an accelerator unit.
False
109
True or False: the major fraction of the electron energy is converted to x-rays.
False
110
True or False: the x-ray spectrum produced is influenced by the thickness of the target.
True
111
True or False: the x-rays produced would heat up the target.
False; the x-ray absorption in the target causes the heating up
112
True or False: The electrons impinge on a large area of the target in a clinical accelerator.
False; they impinge on a small circle, about 3 mm
113
True or False: Therapy x-ray beams used in the kV region are medium filtered.
True; they are not highly filtered, filtered medium to harden the beam by removing low-energy x-photons
114
True or False: The beam quality of kilovoltage therapy x-ray beams can be adequately represented by the HVL.
False
115
True or False: For the accelerator photon beams, AAPM TG-51 recommends TRP20/10 as the beam quality specifier.
False; AAPM TG-51 recommends PDD (10, 10x10, SSD)X as beam quality specifier
116
True or False: The (Bremsstrahlung) X-ray spectrum produced in the target has a continuous spectrum.
True
117
True or False: the maximum energy of the photons in the x-ray spectrum exceeds the energy of the electrons incident on the target.
False
118
True or False: Characteristic x-rays are also produced in the target along with the continuous x-ray spectrum.
True
119
True or False: the intensity of x-ray spectrum produced by a linear accelerator is maximum along the central axis of the beam and decreases considerably with increasing angle with respect to the central axis.
True
120
The kV x-ray unit used in orthovoltage therapy must have a target _____.
Of high Z
Of high melting point
121
The output of kilovoltage therapy unit is roughly proportional to _____.
Tube voltage kV^2
Z of target
122
What distinguishes an x-ray photon from a gamma ray photon?
Origin
123
True or False - When a high-energy electron (in the MeV range) collides with a target this interaction can occur: inelastic collision with electrons.
True
124
True or False - When a high-energy electron (in the MeV range) collides with a target this interaction can occur: elastic collision with nuclei.
True
125
True or False - When a high-energy electron (in the MeV range) collides with a target this interaction can occur: inelastic collision with nuclei.
True
126
True or False - When a high-energy electron (in the MeV range) collides with a target this interaction can occur: elastic collision with neutron.
False
127
True or False - When a high-energy electron (in the MeV range) collides with a target this interaction can occur: inelastic collision with proton.
False
128
The Bremsstrahlung production probability for the target material varies as _____.
Z^2
129
The efficiency of Bremsstrahlung production for the target material is proportional to _____.
Z E
130
The maximum photon energy of the Bremsstrahlung spectrum is determined by the _____.
Maximum mA
131
True or False - the Bremsstrahlung x-ray spectrum produced in a given x-ray target depends on: kinetic energy of the incident electron.
True
132
True or False - the Bremsstrahlung x-ray spectrum produced in a given x-ray target depends on: binding energy of the electrons of the target atom.
False
133
True or False - the Bremsstrahlung x-ray spectrum produced in a given x-ray target depends on: target Z.
True
134
True or False - the Bremsstrahlung x-ray spectrum produced in a given x-ray target depends on: target thickness.
True
135
This figure 2 shows the x-ray spectrum produced by the electron beam of _____ energy?
4 MV, 20 MV, 100 kV, or 400 kV
100 kV
136
This figure 2 shows the x-ray spectrum produced by the electron beam of _____ energy?
4 MV, 20 MV, 100 kV, or 400 kV
400 kV
137
This figure 2 shows the x-ray spectrum produced by the electron beam of _____ energy?
4 MV, 20 MV, 100 kV, or 400 kV
4 MV
138
This figure 2 shows the x-ray spectrum produced by the electron beam of _____ energy?
4 MV, 20 MV, 100 kV, or 400 kV
20 MV
139
True or False: Photons lose energy in small increments, thus gradually slowing down in the medium.
False; they either interact or they don’t
140
True or False: Primary photons are the ones transmitted by and have not had any interaction with the medium traversed.
True
141
True or False: Megavoltage photon interactions can release electrons of significant energy.
True
142
True or False: Electrons are exponentially attenuated while traversing matter.
False
143
True or False: Electrons do not produce Bremsstrahlung photons while interacting with matter.
False
144
True or False: Electrons in their interactions can release secondary electrons of finite range.
True; they are called delta rays and they are partly responsible for the buildup exhibited by electron beam depth dose curves.
145
True or False: Compton interactions are like billiard ball type collisions.
True
146
True or False: All inelastic collisions of electrons with atomic electrons lead to ionization of atoms.
False
147
True or False: A pencil beam of electrons incident on a foil spreads into a beam of larger cross-section due to multiple Coulombic interactions with nuclei of atoms.
True
148
True or False: A narrow beam of photons incident on a foil spreads into a beam of larger cross-section due to multiple interactions with nuclei of atoms.
False
149
True or False: High-energy electrons scatter more than low-energy electrons.
False
150
True or False: High-energy electrons scatter more in high-Z materials.
True
151
To produce an electron-position pair in the vicinity of a nucleus, the interacting photon must have a minimum energy of _____.
1.02 MeV
152
To interact by photoelectric effect, the interacting photon’s energy must be _____.
Equal to or just greater than the binding energy of the electron
153
To undergo a Compton effect, the energy of the interacting photon must be _____.
Much larger than the electron binding energy
154
In photoelectric interaction, the photon loses _____.
All the energy
155
In a Compton interaction, The photon loses _____.
Part of its energy
156
The probability of Compton interaction (i.e., the electronic Compton coefficient) _____.
Decreases with an increase in photon energy
157
As the photon energy increases, the Compton electron gets ejected _____.
More and more in the forward direction
158
In the megavoltage energy range, the predominant interaction in a patient is _____/
Compton
159
In the megavoltage energy range, the predominant interaction in a patient is _____.
Compton
160
The probability of pair production (atomic cross section) in the interacting medium varies as _____.
Z^2
161
The probability of photoelectric effect (atomic cross section) in a medium roughly varies as _____.
Z^3
162
In pair production, after expending energy for the creation of the pair, the excess photon energy _____.
Is shared by the electron and positron
163
As the photon energy increases, the probability of photoelectric effect roughly varies as _____.
1/E^3
164
As the photon energy increases, the probability of photoelectric effect roughly varies as _____.
1/E3
165
At the end of its range in the medium in pair production, the positron _____.
Is annihilated, resulting in two annihilation photons
166
Photoelectric effect involves _____.
A bound electron
167
A Compton interaction involves a photon interacting with _____.
A free electron
168
Energy losses by electrons (in their collision interactions) are _____.
Dependent of Z
169
Energy losses in radiative collisions, when electrons are stopped in medium, vary as _____.
Z^2
170
The probability for photoelectric absorption is maximum when the gamma energy is _____.
Equal to the electron binding energy
171
The threshold energy (in MeV) for pair production in the Coulombic Field of the nucleus is _____.
1.02
172
The photoelectric cross-section _____.
Depends on both the photon energy and the atomic number of the medium
173
Compton mass attenuation coefficient for a given gamma energy depends on _____.
The electron density of the medium
174
Elastic scattering is characterized by _____.
Conservation of kinetic energy
175
In Compton scattering, the energy of the incident photon _____.
Is equal to the energy of the scattered photon and the recoil electron (BE is negligible)
176
The threshold energy in (MeV) for pair production in the vicinity of an electron is _____.
2.04
177
The Compton (electronic) scattering cross-section depends on _____.
The gamma energy only
178
The mass attenuation coefficient due to Compton interactions _____.
Decreases with energy and depends on electron density of medium
179
For photoelectric absorption to take place, the gamma energy should be _____.
Exactly equal to or slightly larger than the electron binding energy
180
True or False: When a photon traverses a medium, no interaction can occur.
True
181
True or False: When a photon traverses a medium, complete absorption can occur.
True
182
True or False: When a photon traverses a medium, scatter can occur.
True
183
True or False: When an electron traverses a medium, no interaction can occur.
False
184
True or False: When an electron traverses a medium, complete absorption in an inelastic collision can occur.
False
185
True or False: When an electron traverses a medium, complete conversion into a Bremsstrahlung photon in a radiative collision can occur.
True
186
In Compton scatter, the energy of the back-scattered photon (in MeV) is _____.
0.255
187
The energy loss of electrons in water or tissue is roughly given (in MeV/cm) by _____.
2
188
True or False: Multiple scattering of a pencil beam of electrons in a scattering foiled results in its angular spread.
True
189
True or False: Multiple scattering of a pencil beam of electrons in a scattering foiled results in its energy degradation.
True
190
True or False: Multiple scattering of a pencil beam of electrons in a scattering foiled results in Bremsstrahlung contamination.
True
191
True or False: In a kV x-ray unit, the electrons are accelerated by a constant or pulsating positive DC potential.
True
192
True or False: In an accelerator, the electrons are accelerated by an alternating AC voltage.
False
193
True or False: In an accelerator the source of microwave energy is a klystron or a magnetron.
True
194
True or False: In a microtron the electrons are accelerated in a straight path.
False
195
True or False: Much of the electron energy deposited in the x-ray target reappears as heat.
True
196
True or False: An efficient target cooling system is necessary in therapy machines
True
197
True or False: A flattening filter is used in a Co^60 beam to produce a uniform (flat) beam profile.
False
198
True or False: In a Co^60 unit the treatment time is controlled using a transmission monitor.
False
199
True or False: there is no radiation from a Co^60 machine when the machine is switched off.
False
200
True or False: There is no radiation from an accelerator when the machine is switched off.
True
201
True or False: A Co^60 source is produced by irradiating a Co^59 cylinder for source dimensions in a nuclear reactor.
False
202
True or False: The output of a Co^60 unit has to be measured only during source loading. The output on any treatment day can be determined using the exponential decay law.
False
203
True or False: The kV x-ray beam used in radiation therapy is monoenergetic.
False
204
True or False: The filter inserted in the beam path of a kV x-ray unit to preferentially absorb the soft components of the x-ray spectrum is known as the “inherent filtration.”
False
205
True or False: If two fields have the same area, they will have the same equivalent square field.
False
206
A flattening filter is used in an accelerator to _____.
A. Attenuate the clinical Photon beams and to reduce the beam output
B. change the spectra of the photon beam
C. Filter the low energy photons and to harden the beam
D. Get a flat beam profile at the clinical depth
D. Get a flat beam profile at the clinical depth
207
The flattening filter used in a linear accelerator: (more than one answer may apply)
A. Makes the beam quality uniform across the field width
B. Hardens the beam more in the central region compared to the peripheral regions
C. Produces a horn in the cross-beam profile at shallower depths
D. Is cone shaped to attenuate more in the central region compared to the peripheral region
B. Hardens the beam more in the central region compared to the peripheral regions
C. Produces a horn in the cross-beam profile at shallower depths
D. Is cone shaped to attenuate more in the central region compared to the peripheral region
208
The flattening filter position in the beam path is:
A. Immaterial
B. Critical
C. Not very critical
B. Critical
209
Any error in the reproducible positioning of the flattening filter will affect: (more than one answer may apply)
A. Beam flatness
B. beam symmetry
C. beam output
D. None of the above
A. Beam flatness
B. beam symmetry
C. beam output
210
An added filter used with a therapy kV unit:
A. Increases the output
B. “Softens” or reduces the effective energy of the beam
C. Achieves desired filtration for therapeutic purposes
C. Achieves desired filtration for therapeutic purposes
211
The effective energy of an x-ray beam is the energy of that monoenergetic beam that would:
A. Give the same exposure rate at a reference distance as the x-ray beam in question
B. give the same HVL as the x-ray beam in question
C. Have the same inherent and added filtration in the beam path
B. give the same HVL as the x-ray beam in question
212
The target of a therapy x-ray tube must have: (more than one answer may apply)
A. A high Z
B. A high melting point
C. Low thermal conductivity
D. Low specific heat
A. A high Z
B. A high melting point
213
The efficiency of x-ray production in the kV x-ray therapy tubes is about:
A. 0.1%
B. 1%
C. 5%
D. 10%
B. 1%
214
The focal spot of a kV s-ray therapy tube is about:
A. 1 mm
B. 3 mm
C. 10 mm
B. 3 mm
215
The focal spot of a clinical linac is about:
A. 1 mm
B. 3 mm
C. 10 mm
B. 3 mm
216
For a therapy x-ray unit operating at 150 kVp, the maximum energy (in keV) of the photon produced in the target is:
A. 150
B. <150
C. >150
A. 150
217
The source of electrons in an electron accelerator is the:
A. Klystron
B. Accelerating waveguide
C. Electron gun
D. Magnetron
C. Electron gun
218
Some important features of a linac compared to a Co^60 unit are: (more than one answer may apply)
A. Higher beam output
B. Sharper beam
C. Less maintenance cost
D. Less complex in design
A. Higher beam output
B. Sharper beam
219
Modern accelerators can produce: (more than one answer may apply)
A. Asymmetric fields
B. Circular fields
C. Custom fields
A. Asymmetric fields
220
A _____ target is used in a high-energy linear accelerator.
A. Transmission type
B. Reflection type
C. Refraction type
A. Transmission type
2nd Ed Medical Dosimetry Certification Study guide by K.N. Govinda Rajan, Ph.D.
A.
B.
C.
D.
221
The skin sparing effect will be highest for _____.
A. A diagnostic x-ray beam
B. A orthovoltage x-ray beam
C. An electron beam
D. A megavoltage X-ray beam
D. A megavoltage x-ray beam
*This is because of the long range of electrons produced by a photon beam.*
2nd Ed Medical Dosimetry Certification Study guide by K.N. Govinda Rajan, Ph.D
