1
Q
What are beta particles?
A
Negatively charged (electrons)
2
Q
What are gamma rays?
A
No charge and resemble x-rays, but differ in origin
3
Q
What are the types of radiation emitted from the nucleus?
A
Alpha, Beta, Gamma Rays
4
Q
What are alpha particles?
A
positively charged (helium nuclei) (2 protons, 2 neutrons)
5
Q
What is activity?
A
The radioactive sources rate of decay
6
Q
What is the SI unit of activity?
A
Becquerel (Bq)
7
Q
What is brachytherapy?
A
“Short-distance therapy” that uses radioactive materials to treat certain cancers internally
8
Q
What is half-life (T1/2)?
A
The duration of time it takes for the activity to decay to half of the original value
9
Q
What are external brachytherapy applicators?
A
Plastic molds that conform to patient’s skin surface with source placed on the outer surface of mold.
10
Q
What are intracavitary brachytherapy applicators?
A
Applicator with radioactive source placed within a body cavity
11
Q
What is mean life?
A
The average lifetime decay
12
Q
What are interstitial brachytherapy applicators?
A
Radioactive sources placed with needles, wires, or seeds directly into malignant tissues
13
Q
Iodine (I-131) half life? examples of use?
A
Half-life: 8 days
Examples of use: thyroid cancer treatment
14
Q
Yttrium (Y-90) half life? examples of use?
A
Half-life: 2.67 days
Examples of use: Liver cancer and lymphoma treatments
15
Q
Palladium (Pd-103) half life? examples of use?
A
Half-life: 17 days
Examples of use: Permanent implants for prostate cancer treatment
16
Q
Strontium (Sr-89) half life? examples of use?
A
Half life: 50.5 days
Examples of use: treats pain caused by bone metastasis
17
Q
Gold (Au-198) half life? examples of use?
A
Half-life: 2.7 days
Examples of use: permanent implants (seeds) for prostate cancer treatment
18
Q
Iodine (I-125) half life? examples of use?
A
Half life: 59.4 days
Examples of use: Permanent implants for treatment of prostate cancers
19
Q
Strontium (Sr-90) half life? examples of use?
A
Half life: 28 years
Examples of use: Treats cancers in the eye (pterygium)
20
Q
Cesium (C-137) half life? examples of use?
A
Half-life: 30 years
Examples of use: Brachytherapy for cancers of the cervix or uterus
21
Q
Iridium (Ir-192) half life? examples of use?
A
Half-life: 73.8 days
Examples of use: HDR treatments and made of nylon ribbons with seeds
22
Q
Radium (Ra-226) half life? examples of use?
A
Half life: 1,622 years
Examples of use: Original radioactive isotope
23
Q
Cobalt (Co-60) half life? Examples of use?
A
Half-life: 5.26 years
Examples of use: External beam treatments
24
Q
What is the cathode?
A
Negatively charged electrode with a tungsten filament that releases electrons when heated
25
What is the anode?
Positively charged electrode made of tungsten and is also known as the target
26
MV linear accelerators energy range?
4 MV to 25 MV
27
Orthovoltage energy range?
150 to 500 kV
28
Superficial therapy energy range?
50 to 150 kV
29
What is the type of target used in MV machines?
Transmission target
30
What are the types of target interactions?
(aka electron interactions with matter?)
Bremsstrahlung and Characteristic
31
What is frequency?
The number of waves that pass through a point in a certain amount of time (SI unit is Hz or sec-1)
32
What is wavelength?
The measured distance between two specific points of the wave (SI unit is meter)
33
What is velocity?
How fast the wave is traveling (speed and direction) (SI unit is m/sec)
34
Describe a bremsstrahlung interaction
The electron slows down as it approaches the nucleus and then changes its direction
35
Describe a characteristic interaction
Incoming electron interacts with another inner shell electron, causing the inner shell electron to be ejected and an outer shell electron fill the new vacancy
36
What is the speed of light?
3 * 10^8 m/sec
37
What is the inverse square law?
Beam intensity is inversely proportional to the square of the distance from the source
38
What is beam quality?
The beam's ability to penetrate
39
What is amplitude?
Half the distance from one crest to one valley; represents the strength or intensity of a wave
40
Quality Factor for X-rays, Gamma rays, Beta particles, and electrons
1 (one)
41
What is attenuation in matter?
The beam decreases in intensity because it is either absorbed or scattered in a different direction as it travels through matter
42
Quality factor for protons?
2
43
What are the photon interactions in matter?
Coherent (elastic) scattering
Photoelectric effect
Compton scattering
Pair production
Photodisintegration
44
Quality factor for neutrons?
3 to 10 (or up to 20)
45
What is coherent (elastic) scattering?
The photon interaction occurs with an outer shell atomic electron and the photon becomes redirected, or scattered, from its original path without a change in energy
46
What is the photoelectric effect?
The photon interacts with an inner shell electron, is then absorbed by this electron, and its energy is transferred.
47
Quality factor for heavy particles (alpha particles)?
20
48
What is the secondary effect of the photoelectric effect?
Characteristic x-rays (or an Auger electron)
49
What photon interaction is most common in the diagnostic energy range?
Photoelectric effect
50
What is compton scattering?
The photon interacts with an outer shell atomic electron and gives up partial energy before it changes direction (and the outer shell electron is ejected as a compton electron)
51
What is pair production?
Incoming photon disappears (fully absorbed) and reappears an an electron-positron pair
52
What is the threshold energy for pair production?
Greater than 1.022 MeV
53
What is the most common photon interaction in radiation therapy?
Compton scatter
54
What are photonuclear reactions (photodisintegration)?
Photon goes into nucleus and neutron comes out; occurs in high Z (atomic number) materials such as the collimating jaws
55
SI unit for absorbed dose
Gray (Gy), which equals J/kg
56
Traditional unit for absorbed dose
Rad (radiation absorbed dose)
57
What is the neutron scatter threshold?
Greater than 10 MV
## Footnote
Neutrons are generated in linacs when the photon energy exceeds the threshold for photoneutron reactions, typically above 10 MV.
58
What is absorbed dose?
Unit to describe the amount of energy that has been absorbed in a certain amount of matter
59
What is dose equivalent?
A unit that expresses the amount of radiation that is absorbed by a person, while factoring in the biologic effects of the different types of radiation
60
SI unit for the Dose Equivalent
Sievert (Sv)
61
Traditional unit for Dose Equivalent
Rem (Roentgen equivalent man)
62
What is exposure (roentgen)?
Measures the total number of ionizations produced by photons in a unit mass of air
63
SI unit for exposure
C/kg
Traditional unit is R (Roentgen)
1 R = 2.58 x 10^-4 C/kg
64
What is effective dose?
Measures the difference of response to radiation for different organs and tissues within the body accounting for radiation sensitivities and different organs and tissues
65
What is Air KERMA?
Describes a quantity for indirectly ionizing radiation.
KERMA = Kinetic energy released in the medium per unit mass at a specific point
66
What is a dose-response curve/relationship?
A graph that shows information on the cell's response to radiation and cell survival in the presence of radiation.
67
What is D₀ (or D37)?
Represents a dose after which only 37 % of the cell population will survive
In radiation biology, D₀ (D-zero) represents the mean lethal dose — the dose of radiation that results in an average of one lethal event per cell, leading to a reduction in cell survival to approximately 37% (1/e) of the original population. It is derived from the exponential survival curve of cells exposed to radiation and reflects the cell's inherent radiosensitivity. A higher D₀ value indicates greater radioresistance.
68
Extrapolation Number (n)
Is the number of cells or the target number
69
Quasi-threshold dose (Dq)
Represents the cells' capability to repair (shoulder region on cell survival curve)
Dq in radiobiology stands for quasi-threshold dose, a key parameter in cell survival curves that quantifies the width of the shoulder region on the curve. This shoulder represents the cell's ability to repair sublethal damage at low radiation doses before exponential cell killing begins.
70
What is the most radiosensitive part of the cell?
DNA
71
What is the law of Bergonie and Tribondeau?
The effects of radiation are greater for cells that divide rapidly, cells that are immature with a long mitotic future, and undifferentiated.
72
What is the law of Ancel and Vitemberger?
The extent of radiation damage can change depending on the cells external factors before, during, or after the delivery of radiation.
Ancel and Vitemberger proposed a modification to the Law of Bergonie and Tribondeau, stating that all cells are equally sensitive to radiation damage for a given dose, but the expression of that damage depends on cell division. Cells that divide rapidly (e.g., stem cells, epithelial cells) appear more sensitive because they express damage sooner, while slowly dividing or non-dividing cells may not show effects until they attempt to divide. This concept emphasizes that biological stress from radiation is only revealed during mitosis, not at the time of exposure.
73
What is the therapeutic ratio?
Therapeutic ratio = (Normal tissue tolerance dose)/(Tumor lethal dose)
74
What is LET?
Linear Energy Transfer
The rate that energy is deposited through matter as it travels through it
75
LD 50/30?
Radiation dose that would cause 50 % of the population to die in 30 days.
LD 50/30 = 4-5 Sv
76
What is RBE?
Relative Biological Effectiveness
The ability for the type of radiation to produce biological damage
77
What is the oxygen effect?
The presence of oxygen during a radiation treatment will greatly increase the radiosensitivity of a cell
78
Oxygen Enhancement Ratio for X-rays (OER)
2.5 to 3.0 in human cells
79
What is a common free radical?
Hydrogen peroxide (H202)
80
What is direct effect/damage?
Radiation hits the target (DNA)
81
What is the most radiosensitive part of the cell cycle?
M Phase (and also the end of G2)
82
What is indirect effect/damage?
Radiation first hits WATER within the cells, which then damages DNA
83
What is the most radioresistant part of the cell cycle?
S Phase
84
What are the 5 Rs of radiobiology?
Repair, Repopulation, Reoxygenation, Redistribution, Radiosensitivity
85
TD 5/5 for testis?
100 cGy (whole organ)
86
TD 5/5 for skin?
5500 cGy (100 cm2)
87
TD 5/5 for ovary?
200-300 cGy (whole organ)
88
TD 5/5 for bone marrow?
250 cGy (whole organ)
89
What is carcinogenesis?
The formation of cancer cells?
90
What is a deterministic (non-stochastic) response?
Effect occurs depending of the severity of the radiation dose and HAS A THRESHOLD.
Think NOT RANDOM
91
What is a stochastic response?
Effects have a PROBABILITY of occurring depending on the radiation dose and has NO threshold.
RANDOM
92
What is the effect of radiation during the preimplantation stage of pregnancy?
Prenatal death
93
What is the effect of radiation during the stage of major organogenesis (Day 10 to Week 6 of gestation)?
Abnormalities (ex. microcephaly, mental retardation, and damage to the skeleton or sensory organs) or neonatal death
94
What is genetically significant dose (GSD)?
The total dose to gonads that would result in total genetic effect on the population if received by every member of the population
95
What is TD 5/5?
The dose of radiation to healthy tissue that will cause a 5 % chance of complication within five years of the delivered dose.
96
TD 5/5 of small intestine?
Effect?
4000 cGy (3/3 organ)
Obstruction/perforation/fistula
97
TD 5/5 of esophagus?
Effect?
5500 cGy (3/3 organ)
Stricture/perforation
98
TD 5/5 of colon?
Effect?
4500 cGy (3/3 organ)
Obstruction/perforation/ulceration/fistula
99
TD 5/5 of stomach?
Effect?
5000 cGy (3/3 organ)
Ulceration/perforation
100
TD 5/5 of rectum?
Effect?
6000 cGy (3/3 organ)
Proctitis/necrosis/fistula
101
T/F: A treatment plan that utilizes multiple fields will likely be an SSD setup.
False
102
Wilm's tumors are cancer's of the ________.
A. Striated muscle
B. Adrenal gland
C. Smooth muscle
D. Kidney
D. Kidney
103
In linear or non-linear threshold dose-response curves, the following is true of the response:
A. Response will occur at all doses
B. Response may not occur at low doses
C. Response will never be realized
D. Response is proportional to dose
B. Response may not occur at low doses
(Response is proportional to dose when linear)
104
A radiation therapist begins a patient's simulation by creating an immobilization device to secure a patient in place. However, the patient had previously expressed concerns about using the device and did not provide explicit consent for its use at that time. Which of the following legal concerns could arise from this situation?
A. The use of the immobilization device without consent could be considered false imprisonment, as it involves restraining the patient's movement without their consent.
B. The situation could be classified as negligence, since the therapist failed to document the patient's consent for the use of the immobilization device.
C. This could be a breach of confidentiality, as the therapist did not ensure that the patient's concerns were kept private during the treatment.
D. The situation might be considered medical malpractice, due to the potential for physical harm from the use of the immobilization device.
A. The use of the immobilization device without consent could be considered false imprisonment, as it involves restraining the patient's movement without their consent.
105
What interaction is this?
A. Compton effect
B. Photoelectric absorption
C. Photodisintegration
D. Pair production
D. Pair production
106
Two abutting PA fields are to be matched at a depth of 4.7 cm. The beam energy is 10 MV. The field collimator lengths are 12 cm and 15 cm and both are treated using 100 SSD. Calculate the skip gap.
0.63 cm
107
When performing CPR, what is the correct rate of chest compressions per minute?
A. 30 compressions per minute
B. 60 compressions per minute
C. 100-120 compressions per minute
D. As many as possible per minute
C. 100-120 compressions per minute
108
Which of the following is an example of a benign tumor?
A. Lymphoma
B. Sarcoma
C. Carcinoma
D. Meningioma
D. Meningioma
These tumors originate in the meninges, which are the outer three layers of tissue between the skull and the brain that cover and protect the brain just under the skull.
About 80% to 85% of meningiomas are benign. That means they are not cancerous. Many people do very well after diagnosis, especially when the tumor grows slowly and is monitored with regular scans.
109
Which of the following is an example of a noncoplanar beam arrangement?
A. Breast tangent fields
B. Pelvic four field box
C. Stereotactic brain field
D. Whole brain lateral fields
C. Stereotactic brain field
110
Which occurs when a photon interacts with an electron as though it were a free electron. This happens in the outer shells. The encountered electron receives some energy from the photon and is emitted at an angle from the atom.
A. Photoelectric
B. Compton
C. Coherent scattering
D. Pair Production
B. Compton
111
What is the appropriate grade of a tumor where the histopathology closely resembles cells of the tissue of origin?
A. Grade 1
B. Grade 2
C. Grade 3
D. Grade 4
A. Grade 1
112
A patient with a hemoglobin level of 3-6 g/dl would be considered to have:
A. thrombocytopenia
B. neutropenia
C. leukopenia
D. anemia
D. anemia
113
A 52-year-old patient presents with a chronic, itchy rash that has been gradually worsening over the past year. The rash initially appeared as small, scaly patches on the trunk and has now progressed to larger, plaque-like lesions. The patient also reports occasional night sweats and weight loss. A skin biopsy reveals T-cell lymphoma. What is the likely diagnosis?
A. Hodgkin's lymphoma
B. Follicular lymphoma
C. Mantle cell lymphoma
D. Mycosis fungoides
D. Mycosis fungoides
114
The purpose of the flattening filter in the linac is to:
A. Direct the stream of electrons out toward the collimator opening
B. Prevent deflection of microwaves
C. Evenly distribute and spread out the raw electron beam across a specified area
D. Evenly distribute the energy of the photon beam across a specified area
D. Evenly distribute the energy of the photon beam across a specified area
115
In a linear accelerator, dynamic wedging is a technique used to shape the dose distribution of the radiation beam. Which of the following is primarily utilized to achieve dynamic wedging?
A. Physical wedge filters
B. Collimator blocks
C. Independent jaw movement
D. Bolus materials
C. Independent jaw movement
116
At what anatomical location does the trachea bifurcate into the right and left main stem bronchi?
A. Alveoli
B. Pleura
C. Carina
D. Primary bronchi
C. Carina
117
Transient dysphagia is an acute side effect after irradiation of the mantle field for Hodgkin lymphoma. Dysphagia is:
A. Difficulty breathing
B. Difficulty swallowing
C. Discomfort to stomach
D. Difficulty urinating
B. Difficulty swallowing
118
A drug used to relieve symptoms of nausea and vomiting due to irradiation is a/an:
A. laxative
B. analgesic
C. antiemetic
D. antidiarrheal
C. antiemetic
119
A common chemotherapy treatment used to treat non-Hodgkin's lymphoma is:
A. CHOP
B. CMF
C. MOPP
D. ABVD
A. CHOP
120
Which of the following acquires single projection images used to produce a 3D reconstruction that can be compared to the CT simulation image?
A. MV imaging
B. CT scan
C. kV imaging
D. cone beam CT
D. cone beam CT
121
During a staff meeting at a radiation oncology clinic, a team member makes an unsubstantiated negative comment about a colleague's professional skills and work ethic in front of other staff members. The colleague's performance has not been formally reviewed or documented, and there is no evidence to support the claims made. What type of legal issue could this situation potentially represent?
A. Defamation, specifically slander, since the comments were spoken and made in a professional setting
B. Negligence, because the team member failed to conduct a proper review before making the comments
C. Breach of confidentiality, as the discussion involved sensitive information about a colleague's performance
D. Harassment, due to the negative impact of the comments on the colleague's work environment
A. Defamation, specifically slander, since the comments were spoken and made in a professional setting
122
Which of the following gynecological malignancies is most likely to require irradiation of the inguinal nodes?
A. cervical
B. ovarian
C. endometrial
D. vaginal
D. vaginal
123
Which of the following is NOT a division of the pharynx?
A. Laryngopharynx
B. Nasopharynx
C. Retropharynx
D. Oropharynx
C. Retropharynx
124
The quality of the MV portal imaging is low due to:
A. increased contrast
B. increased distance
C. increased scatter
D. increased window level
C. increased scatter
125
Which of the following is false regarding an IMRT plan?
A. IMRT uses inverse planning, defining dose first
B. IMRT plans are more forgiving of patient motion and setup error
C. IMRT plans require more extensive quality assurance
D. IMRT allows higher dose to tumor while minimizing normal tissue dose
B. IMRT plans are more forgiving of patient motion and setup error
126
Which of the following is not included in a radiation therapy prescription?
A. bolus
B. dose per fraction
C. MU
D. total dose
C. MU
ARRT Radiation Therapy
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