Safety Exam Flashcards
1
Q
The probability of occurrence of photoelectric absorption _________ as the energy of the incident photon decreases and the atomic number of the irradiated atoms _________.
A
increases markedly; increases
2
Q
Alpha particles have a radiation weighting factor (WR) that is numerically equal to
A
20
3
Q
An effect which increases in severity as the dose increases above a threshold limit is the main
A
deterministic effect
A deterministic effect, formerly called a non-stochastic effect, is defined as a somatic effect that increases in severity as a radiation dose increases above the dose threshold. Deterministic effects may be early, i.e., erythema, or late as with decreased fertility or organ atrophy.
4
Q
The radiation a person receives from the sun (cosmic radiation) is categorized as:
A
natural background radiation.
5
Q
With regard to the ALARA principle, the responsibility of the radiographer is to:
A
keep radiation exposures at the lowest levels possible.
6
Q
Isotopes have the same number of _______ and different number of ______
A
protons; neutrons
7
Q
The most commonly altered molecule when the human body is exposed to low LET radiation is:
A
water
When ionizing radiation enters the body, it may strike any of the elements or molecules found in the body. Since approximately 85 percent of the body is composed of water (H2O) this is the most common molecule that is ionized during an irradiation. When a water molecule is struck by high-energy radiation, much of this absorbed energy will result in the removal of electrons and the production of charged particles called ions and free radicals by a process called hydrolysis. These chemically active elements can undergo a chemical recombination that can result in the formation of toxic compounds including hydrogen radicals, hydroxyl radicals, and hydrogen peroxide. Since this process requires the formation of dangerous compounds which than alter the cell, this is described as an indirect effect.
8
Q
Which of the following radioisotopes is used for HDR gynecological brachytherapy procedures?
A
Ir-192
9
Q
Which of the following is NOT true regarding electromagnetic radiation?
A
Wavelength is measured in hertz
10
Q
________ describes the thickness of the medium needed to attenuate the beam’s original intensity in half.
A
half-value layer
11
Q
Proton and alpha particles exhibit a _______ peak at the end of their range of travel, where most of their energy is deposited.
A
Bragg
12
Q
Decay constant (λ) can be determined by dividing the element’s half-life by:
A
0.693
13
Q
Which photon interaction with matter is most likely to occur with radiation therapy delivery via orthovoltage?
A
photoelectric effect
14
Q
When calculating attenuation with this formula, Ix = Ioe-µx , what does µ represent?
A
linear attenuation coefficient of the material the beam is passing through
15
Q
According to the NCRP, the annual equivalent dose limit for the deterministic (somatic) effects for the lens of the eye for an occupational worker is:
A
150 millisievert
16
Q
According to the current NCRP recommendations, the guidance level for cumulative exposures should be calculated using the formula:
A
10 millisievert x age in years
17
Q
As a general rule, any short-lived radionuclide may be disposed of by any normal means after undergoing:
A
10 half-lives in the radiation decay area
18
Q
A pregnant female has undergone a radiation therapy procedure resulting in an estimated fetal dose of 1.3 mSv. A reasonable recommendation by the radiation safety officer would be to:
A
Indicate to the individual that no significant risk to the fetus has occurred
19
Q
Which statement about ACR MR Safety Zone 4 is true?
A
Zone 4 is synonymous with the room containing the MR scanner.
Zone 4 is the scanner room itself, so b) is true and c) is false. Family members may be allowed in the scanner room provided they have been appropriately screened, so a) is false. The door to the scanner room is not locked and is frequently left open when scanning is not in progress (though we recommend having a strap across it to prevent inadvertent entry). Ferromagnetic materials should not be brought into Zone 4 as the risk of them being propelled into the scanner is high.
20
Q
A cell is in _____ when it is not undergoing mitosis or meiosis.
A
interphase
21
Q
Two OH* free radicals can join to form _____ molecules.
A
hydrogen peroxide
22
Q
Which of the following are types of ionizing radiation that produce virtually the same biologic effect for equal absorbed doses in body tissue?
A
X-rays, beta particles, and gamma rays
23
Q
The steps, or rungs, of the DNA ladder-like structure consist of complementary chemicals that are:
A
pairs of nitrogenous bases.
24
Q
A biologic reaction is produced by 4 Gyt of a test radiation. It takes 24 Gyt of 250-kVp x-rays to produce the same biologic reaction. What is the relative biologic effectiveness (RBE) of the test radiation?
A
6
25
It is recommended that the fetus should not exceed a dose equivalent of:
5 millisievert for the entire gestation
26
Two half-value layers (2 HVL's) reduce the x-ray beam intensity to _______ of its original value.
one fourth
27
The quantity of photons in an x-ray beam is directly proportional to _____________.
tube current
## Footnote
Although there is a relationship between kVp and photon quantity, the relationship is more exponential, not proportional. The anode temperature rating is irrelevant and filtration is indirectly related. As tube current increases, the number of photons in the beam increases in direct proportion.
28
No matter which direction the Compton scatter photon goes, it retains approximately:
two thirds of its energy
## Footnote
The Compton scatter photon retains approximately two thirds of its energy.
29
The millisievert (mSv) is equal to _____ of 1 sievert.
1/1000
30
The central nervous system syndrome occurs following a whole body dose of _____ cGy or more.
5000
31
The chemical properties of an atom are primarily controlled by its:
number of protons
32
About 99% of the atom's mass is located within the:
nucleus
33
Given two x-rays, one of 50 keV and the other 70 keV, the 70 keV x-ray:
has a higher frequency
34
At energies above 10MeV, x-ray photons may interact directly with the atomic nucleus causing the emission of nuclear fragments in a process called:
photodisintegration
35
According to quantum mechanics, the energy of an x-ray is:
inversely proportional to its wavelength
36
Coherent scattering is most likely to occur ____________, even though some of this unmodified scattering occurs throughout the diagnostic range and may result in small amounts of radiographic fog.
below 10 keV
37
Which of the following is not a type of interaction between x-radiation and biologic matter?
Bremsstrahlung
38
Annihilation radiation is used in which of the following modalities?
Positron emission tomography (PET)
39
If an atom has more protons than electrons it will:
have a positive charge
40
A negative ion is:
an atom with more electrons than protons
41
The general process of a radioactive element giving off excess energy and particles to regain stability is:
radioactive decay
42
Half-life is defined as:
the time it takes for half the remaining atoms in an amount of a radioactive element to decay
43
The half-life of technetium-99m is 6 hours. How many unstable atoms will remain after 12 hours?
One fourth of the original amount
44
When compared with a beta particle, the alpha particle is:
much larger
45
When a filament electron knocks out a K-shell electron from the tungsten target atom, it leads to:
a characteristic x-ray photon
46
When some energy is imparted to the electrons of the atom, they will move to higher energy empty states. This process is called which of the following?
Excitation
47
For members of the general public the ICRP recommends a whole body dose equivalent of:
5.0mSv/year
48
An area where average radiation levels exceed ___ would be designated as a controlled area:
1 mSv per week
49
For members of the general public the ICRP recommends a whole body dose equivalent of:
5.0mSv/year
50
The dose limit for the general public is ___ the dose limit for occupational exposure.
1/10
51
An x-ray photon passes into a cell and strikes a chromosome, causing a point mutation in a DNA molecule. This is classified as a/an:
direct effect
52
The study of a response to radiation or other stimulus occurring to tissues outside the body:
in vitro response
53
Experimental findings indicate that cells are most radiosensitive when irradiated in the:
G2 and M periods
54
The discovery of x-rays in 1895 is credited to______.
Wilhelm Conrad Roentgen
55
The emission of liberated electrons is the primary purpose of the__________.
Cathode
56
The circulator in a linear accelerator does which of the following?
Isolates the klystron from reflected microwave power
57
Orthovoltage x-ray machines have energies in the range of which of the following?
150 kV to 500 kV
58
Lipowitz metal is composed of which of the following?
Tin, bismuth, lead, and cadmium
## Footnote
Lipowitz metal, commonly called Cerrobend, is composed of 50% bismuth, 26.7% lead, 13.3% tin, and 10% cadmium.
59
A radioactive sample is measured to contain 1,000 mBq of radioactivity. If the decay constant of this isotope is 0.105 hr-1, how much activity will remain after 48 hours?
6.474 mBq
## Footnote
At = Aoe–lt = (1000 mCi)e(–0.105)(48) = 6.474 mBq.
60
What is the half-life of gold 198?
2.7 days
## Footnote
Gold 198 is a popular replacement for radium 226 in permanent implants. It has a very short half-life of 2.7 days.
61
Which of the following is an advantage of high-dose rate (HDR) over low-dose rate (LDR)?
HDR can be given on an outpatient basis.
## Footnote
It is suggested that HDR brachytherapy may be preferable to the LDR treatment because HDR can be given on a fractionated outpatient basis.
62
As half-life increases, the overall activity of a radioisotope _____________.
decreases
## Footnote
The relationship between half-life and radioactivity is inversely proportional. As half-life increases, overall activity decreases.
63
Electrons have a quality factor (QF) of _____.
1
64
What is the radiation weighting factor for gamma-rays?
1
65
X-rays have a quality factor of ________.
1
66
The annual dose equivalent limit to the whole body for occupationally exposed individuals is _____ mSv.
50
## Footnote
According to the National Council on Radiation Protection (NCRP) and Measurements Report No. 116, the annual dose equivalent limit to the whole body for occupationally exposed individuals is 50 mSv.
67
The annual dose equivalent limit to the lens of the eye for occupationally exposed individuals is ____ mSv.
150
## Footnote
According to NCRP Report No. 116, the annual dose equivalent limit to the lens of the eye for occupationally exposed individuals is 150 mSv.
68
The annual dose equivalent limit to the heart for occupationally exposed individuals is ____ mSv.
500
## Footnote
According to NCRP Report No. 116, the annual dose equivalent limit to the heart for occupationally exposed individuals is 500 mSv.
69
The monthly dose equivalent limit to an embryo/fetus is ____ mSv.
0.5
## Footnote
According to NCRP Report No. 116, the monthly dose equivalent limit to an embryo/fetus is 0.5 mSv.
70
Thermoluminescent dosimeters are composed of ____.
LiF
## Footnote
The atomic number of LiF is close to that of tissue, so LiF mimics tissue closely and is therefore useful as a patient or phantom dosimeter.
71
Which of the following would not be helpful in a personnel radiation-monitoring program?
Routine blood examinations
## Footnote
Routine blood examinations are not part of a personnel radiation monitoring program. These programs are designed to measure the amount of radiation received by an individual (which could be accomplished by the rest of the possible answers), monitor work areas with excessive dose, and provide a permanent record of radiation received if questions arise at a later time.
72
Which agency provides information and recommendations in the public interest concerning radiation measurements and protection?
NCRP
73
Which particles have the highest linear energy transfer?
Alpha particles
74
Which organization guides specific radiation oncology staff in the development of a quality assurance (QA) program as it relates to treatment planning and delivery?
AAPM
## Footnote
American Association of Physicists in Medicine which is the professional organization for medical physicists, has been a forerunner in the development of minimum standards to guide medical physicists in the development of a QA program as it relates to treatment planning and delivery. The AAPM task group reports outline comprehensive QA programs.
75
This federal agency has as its scope of responsibility the regulation of nuclear reactors; medical, academic, and industrial uses of nuclear materials; and the transport, storage, and disposal of nuclear materials and waste.
NRC
## Footnote
The U.S. Nuclear Regulatory Commission (NRC) regulates nuclear reactors; medical, academic, and industrial uses of nuclear materials; and the transport, storage, and disposal of nuclear materials and waste. The U.S. Environmental Protection Agency and Department of Transportation assist the NRC in fulfilling its mission.
76
The ASRT have developed practice standards for radiation therapists. They are divided into what three sections?
Clinical, quality, and professional performance standards
## Footnote
The professional practice standards are divided into three sections: clinical performance standards, which define activities related to the care of patients and the delivery of procedures and treatments; quality performance standards, which include the activities of the practitioner in the technical areas of performance involving equipment safety and TQM; and professional performance standards, which define activities in the areas of education, interpersonal relationships, personal and professional self-assessment, and ethical behavior.
77
The recommended frequency for checking the audio-visual system in the treatment room is _______________.
daily
78
The tolerance for light/radiation field coincidence on the linear accelerator is _____ mm.
2
79
X-ray output was calibrated during commissioning as 1.0 cGy/MU. During monthly quality assurance checks, the output is calibrated as 1.3 cGy/MU. This monthly output measurement is _____________________.
outside of tolerance limits and action is required
## Footnote
The tolerance limit for monthly x-ray output constancy is 2%. The monthly reading shows a 30% increase beyond the output measured during commissioning. Action is required.
80
A daily quality assurance check for the computed tomography (CT) simulator is to check the CT number accuracy for which of the following?
Water
81
As a result of _______, the intensity of radiation on an object is reduced with distance.
divergence
82
In a linear accelerator, the cathode is analogous to the:
electron gun
83
The linear accelerator operational status that indicates the radiation therapist has initiated a radiation beam is:
beam on
84
When treating with electrons, the carousel rotates to place a _________________ in the beam to spread it out.
scattering foil
85
What causes the "horns" on a photon beam?
flattening filter
86
Which of the following terms means "random in nature"?
Stochastic
87
Occupational dose refers to
the biological effectiveness of radiation absorbed by a radiation worker. It is measured in rems.
88
A defined area in which the occupational exposure of personnel to radiation is under the supervision of the radiation protection supervisor, and occupied by radiation workers is a(n)
controlled area
89
The amount of material required to reduce exposure rate or radiation intensity to one-tenth of the original value is defined as:
tenth value layer
90
Who is primarily responsible for checking the engineering capabilities of the linear accelerator?
medical physicist
91
Dose limits are based on a ________________ dose-response relationship to radiation.
linear, nonthreshold
92
Radioactive material is measured in _______.
becquerel
93
The unit of measure of radiation in air is the ________.(SI)
C/kg
94
The maximum weekly permitted equivalent dose for a controlled area must not exceed
1 mSv.
95
A "Caution - High Radiation Area" warning sign must be posted in all areas where a person could receive an exposure in excess of mSv/hr:
1
## Footnote
"CAUTION HIGH RADIATION AREA" – Signs necessary when dose rate exceeds 1mSv per hour and for areas in which the concentrations of radioactivity in air exceed certain standards specified in the regulations.
96
A Geiger-Muller counter is a(n) ________________________.
gas-filled detector
## Footnote
A Geiger-Muller counter is a gas-filled detector.
97
What is the purpose of a maze in the design of linear accelerator vaults?
prevent leakage and scattered radiation
98
All of the following are passive monitoring devices except:
pocket ionization chambers
99
The intensity of a radiation beam is measured at 10.0 mR/hr at a distance of 20 cm. What will be the intensity of this beam at 30.0 cm?
4.44 mR/hr
100
Matter is measured in ___________.
kilograms
101
Ice and steam are examples of two forms of ___________.
matter
102
What is the electromagnetic wave equation?
c = fλ
103
The intensity of radiation on an object is reduced with distance because the radiation ___________.
is spread out over a greater area
104
The lowest energy range of the electromagnetic spectrum is ____________.
radio waves
105
Gamma rays are produced in the ___________ of the atom.
nucleus
106
Alternating current is produced by a ___________.
generator
107
A charged particle in motion creates a(n) ______________.
magnetic field
108
What type of material can be made magnetic when placed in an external magnetic field?
Ferromagnetic
109
During an exposure, most of the ________ energy of the projectile electrons is converted to ________.
kinetic, heat
110
Electron interactions at the inner-shell of the target atoms produce _____ radiation.
characteristic
111
Characteristic K-shell x-rays have an effective energy of _____ keV.
69
112
Most of the x-rays produced at the target are _______________.
bremsstrahlung
113
Distortion can be reduced by ____________________________.
placing the object plane perpendicular to the image plane
114
The central nervous system syndrome occurs following a whole body dose of _____ Gy or more.
50
115
A person subjected to 50 Gy to the whole body may survive for __________ before death occurs.
3 days
116
_____________ are among the most radioresistive species.
Cockroaches
117
Death from acute radiation exposure follows a __________________ dose-response relationship.
nonlinear, threshold
118
The stem cells of the ovaries multiply during _________________.
fetal growth
119
A single chromosome aberration represents ______________ to the DNA within the chromosome.
severe damage
120
The most radiosensitive cells in the hematopoietic system of the human body are the _________________.
lymphocytes
121
____________ is a stochastic effect of radiation exposure.
Cancer
122
The theory of radiation hormesis suggests that radiation doses below 0.1 mGy are _____________.
beneficial
123
The most radiosensitive period during pregnancy for radiation induced congenital abnormalities is during the _____________________.
first trimester
124
A tenth-value layer is equal to ________ half-value layers.
3.3
125
What is the NCRP?
National Council of Radiation Protection.
126
What is the best approach to occupational radiation exposure?
Follow the concept of ALARA.
127
What is the primary purpose of the gantry in a Computed Tomography (CT) scanner?
To house the X-ray tube and detectors
128
What safety feature is crucial to prevent excessive radiation exposure during a CT scan?
Automatic exposure control (AEC)
## Footnote
Automatic exposure control (AEC) adjusts the radiation dose based on the patient's size and anatomy, ensuring optimal exposure without unnecessary radiation.
129
What role does the X-ray tube play in CT imaging?
To generate ionizing radiation
130
How does pitch affect the CT scan?
It influences the scan time and patient dose
## Footnote
Pitch is the ratio of table movement to the X-ray beam width, influencing the scan time and patient dose in a CT scan.
131
How does pitch affect the CT scan?
It controls the couch speed
## Footnote
Pitch is the ratio of table movement to the X-ray beam width, influencing the scan time and patient dose in a CT scan.
132
How does the imaging system, such as cone-beam CT, contribute to the accuracy of radiation therapy with a linear accelerator?
It generates patient images for target verification
## Footnote
Imaging systems like cone-beam CT provide detailed patient images used for precise treatment planning, ensuring accurate targeting of the tumor during radiation therapy.
133
What is the primary purpose of the gantry in a linear accelerator used for radiation therapy?
To rotate around the patient delivering radiation from various angles
## Footnote
The gantry in a linear accelerator rotates around the patient, allowing precise delivery of radiation from different angles to target cancerous tissues.
134
During a daily routine quality assurance check of a linear accelerator, what beam parameter is assessed to ensure accurate beam targeting?
Beam flatness and symmetry
## Footnote
Assessing beam flatness and symmetry during a quality assurance check ensures uniform dose distribution and accurate targeting.
135
Why is beam energy an important consideration in radiation therapy with a linear accelerator?
It affects the penetration of the radiation beam
## Footnote
Beam energy influences the penetration of the radiation beam, ensuring it reaches the targeted depth within the patient's body.
136
Which of the following is a critical safety consideration when dealing with MRI technology?
Metal implants in the body
## Footnote
Metal implants can interact with the strong magnetic fields generated by MRI machines, potentially causing harm to the patient and compromising image quality
137
During an MRI scan, what is the primary factor contributing to the generation of imaging signals?
Radiofrequency pulses
## Footnote
MRI relies on the excitation of hydrogen nuclei by radiofrequency pulses, leading to the emission of signals used in creating detailed images of the internal structures.
138
What factors contribute to variations in radiation tissue tolerance among different tissues in the human body?
Cellular turnover and vascularization
## Footnote
The ability of tissues to tolerate radiation is influenced by their rates of cellular turnover and vascularization, as these factors affect the tissue's capacity for repair and recovery.
139
How does the concept of radiation tissue tolerance influence treatment planning in radiation therapy?
It guides the selection of radiation therapy techniques
## Footnote
Understanding the radiation tolerance of different tissues helps radiation therapists choose appropriate treatment techniques that maximize effectiveness while minimizing damage to surrounding healthy tissues.
140
In radiation therapy, why is it crucial to consider the difference in radiation tissue tolerance between normal and cancerous tissues?
Cancerous tissues are more sensitive to radiation than normal tissues
## Footnote
Cancerous tissues are generally more sensitive to radiation than surrounding normal tissues, influencing treatment planning to target the tumor while sparing healthy tissues.
141
In the context of radiation therapy safety, what precautionary measures can be taken to minimize late effects on normal tissues?
Proper patient positioning and immobilization
## Footnote
Ensuring accurate and consistent patient positioning and immobilization during radiation therapy sessions contributes to minimizing late effects by precisely targeting the tumor while sparing surrounding normal tissues.
142
What distinguishes early radiation effects on tissues from late effects in the context of radiation therapy?
Early effects occur during treatment, while late effects manifest after a prolonged period
## Footnote
Early effects of radiation therapy typically emerge during or shortly after treatment, whereas late effects may become apparent weeks, months, or even years later.
143
Why is knowledge of a patient's prior surgeries important in radiation therapy planning?
Surgical scars may alter radiation dose distribution
## Footnote
Surgical scars can affect dose distribution, and awareness of prior surgeries is crucial for accurate treatment planning.
144
How can the patient's age influence the response to radiation therapy?
Elderly patients may be more susceptible to radiation effects
## Footnote
Older patients may exhibit increased susceptibility to radiation effects due to factors like reduced tissue resilience.
145
Which radiobiological term describes the undesirable effects of radiation therapy on normal tissues surrounding the treatment area?
Radiation Toxicity
146
What is the purpose of using a QC water phantom during the warm-up and inspection of CT simulators?
To evaluate CT number and noise parameters
147
Why is it essential to inspect the door interlock system during the warm-up of a linear accelerator?
To prevent unauthorized access
148
What is the purpose of primary barriers in radiation therapy facilities?
To shield against direct radiation exposure
149
According to NRC regulations (10 CFR, parts 20 and 35), what are the primary classifications of areas in a radiation therapy facility?
Restricted, Controlled, and Unrestricted
150
Determine the cumulative effective dose (CumEfD) limit to the whole body of an occupationally exposed person who is 46 years old.
460 mSv
151
If a certain dose of radiation produces a skin burn, a higher dose of radiation will cause the skin burn to be more severe; however, a dose below the threshold level for skin burn will
not demonstrate the effect.
152
In CT because of higher effective energy of the x-ray beam, both ____________ and _______________ interactions contribute substantially to the image.
photoelectric; Compton
153
Lower tube current is used in anatomic regions where there is ____________ attenuation because the anatomy is ____________ or _________ dense.
decreased; thinner; less
154
Which of the following is another term for use factor (U)?
Beam direction factor
155
For primary radiation, what is the term that represents a portion of beam-on time that the x-ray beam is directed at a primary barrier during the week?
Use factor
156
When a radiologic technologist declares her pregnancy to her employer, which of the following is appropriate?
She continues to perform her duties without interruption of employment, provided that she has received radiation safety counseling and follows established radiation safety practices.
157
_______________ is essentially the radiation output weighted time that the unit is actually delivering radiation during the week.
Workload
158
Who should determine the exact shielding requirements for a particular imaging facility?
Medical physicist
159
In __________, a neutron transforms itself into a combination of a proton and an energetic electron.
beta decay
160
Considering the design of the medical imaging suites listed below, which suite requires shielding for the highest energy photons?
PET-CT imaging suite
161
At the conclusion of a brachytherapy or diagnostic radionuclide procedure, any residual isotope
is to be returned to its shielded container.
162
A becquerel (Bq) is defined as
1 disintegration per second.
163
Which statement best reflects the consideration of radiosensitivity in pediatric tumors?
Pediatric tumors generally exhibit higher radiosensitivity compared to adult tumors.
## Footnote
Pediatric tumors often demonstrate higher radiosensitivity, influencing treatment strategies.
164
In the context of radiation safety, what is a primary concern when treating morbidly obese patients?
Adequate penetration of radiation through increased tissue thickness is a consideration.
165
In MRI safety protocols, what guidelines should be followed when patients require oxygen tanks?
Use only MRI-compatible oxygen tanks to avoid hazards associated with ferromagnetic materials.
166
How does adjusting kilovoltage (kV) affect image quality and safety in radiation therapy imaging?
Higher kV results in increased image contrast and reduced patient dose.
167
What role does milliampere-seconds (mAs) play in influencing image quality during radiation therapy imaging?
mAs adjustments primarily affect patient dose, with minimal impact on image quality.
## Footnote
Changes in mAs primarily influence patient dose, with limited impact on image quality.
168
How does the severity of Acute Radiation Syndromes (ARS) correlate with the radiation dose received?
Severity increases linearly with higher radiation doses.
## Footnote
The severity of ARS is directly proportional to the radiation dose, with higher doses leading to more severe symptoms.
169
Which of the following is a form of radiation that is capable of creating electrically charged particles by removing orbital electrons from the atom of normal matter through which it passes?
Ionizing radiation
170
In a hospital setting, which of the following professionals is expressly charged by the hospital administration with being directly responsible for the execution, enforcement, and maintenance of the ALARA program?
Radiation Safety Officer
171
Which of the following radiation quantities is intended to be the best overall measure of the biologic effects of ionizing radiation?
Effective dose
172
Electromagnetic radiation travels or propagates through space in the form of a wave but can interact with matter as a particle of energy called a photon. This dual nature is referred to as
wave-particle duality.
173
What is the most common unit of measure of equivalent dose?
Millisievert
174
Two cGy equals
.02 Gy.
175
Of the two sources of ionizing radiation listed below, which source remains fairly constant from year to year?
Natural
176
0.2 Gy equals
200 mGy.
177
The total kinetic energy released in a unit mass (kilogram) of air and expressed in metric units of joules per kilogram is
air kerma.
178
What do radiation weighting factors take into consideration?
The fact that some types of radiation are more efficient at causing biologic damage than other types of radiation for a given dose
179
Cataract formation, fibrosis, reduced fertility, and sterility are classified as
late tissue reactions of ionizing radiation.
180
Which of the following formulas is used to calculate effective dose?
EfD = D x WR x WT
181
What instrument can be calibrated to read air kerma?
Standard, or free-air, ionization chamber
182
In therapeutic radiology what SI units are now routinely used to specify absorbed dose?
Gray and centigray
183
What is the maximum period of time that a thermoluminescent ring dosimeter (TLD) may be worn as a personnel device?
3 months
184
What do optically stimulated luminescence dosimeters, thermoluminescent ring dosimeters, and personnel direct ion storage dosimeters have in common?
These devices are all used for personnel monitoring.
185
Which of the following devices contains an aluminum oxide detector?
Optically stimulated luminescence dosimeter
186
When the sensing material contained in the thermoluminescent ring dosimeter is irradiated, which of the following occurs?
Some of the electrons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to higher energy levels or bands.
187
Because of the OSL dosimeter's sensitivity down to as low as 10 µSv for x-ray and gamma ray photons in the energy range 5 keV to 40 MeV, it is an excellent and practical monitoring device for
employees working in low-radiation environments and for pregnant workers.
188
Three different filters are incorporated into the detector packet of the optically stimulated luminescence (OSL) dosimeter. These filters are respectively made of
1. aluminum.
2. copper.
3. molybdenum.
4. rhenium tungsten.
5. tin.
1, 2, and 5 only
189
Whenever the letter "M" appears under the current monitoring period or in the cumulative columns of a personnel monitoring report, it signifies that a (an)
equivalent dose below the minimum measurable radiation quantity was recorded during that time.
190
Adenine bonds only with
thymine.
191
If a person receives radiation exposure sufficient to cause the gastrointestinal syndrome, fatality occurs primarily as a result of
catastrophic damage to the epithelial cells that line the gastrointestinal track.
192
Atrophy refers to
shrinkage of organs and tissues after a high radiation dose is received.
193
During the major response stages of acute radiation syndrome after the prodromal stage and a period of false calm that may last for several days, the stage when symptoms that affect the hematopoietic, gastrointestinal, and cerebrovascular systems occurs, this stage is called
manifest illness.
194
To provide a low-exposure cut-off level so that regulatory agencies may consider a level of effective dose as being of negligible risk, an annual negligible individual dose (NID) of ________________ per source or practice has been set.
0.01 mSv/year
195
If a tumor has a high OER, what does it imply for the radiation therapy treatment?
Higher radiation doses are needed for the same effect in hypoxic areas.
196
If the radiation dose required for a specific effect in a hypoxic environment is 60 Gy, and the dose needed in an oxygenated environment is 30 Gy, what is the Oxygen Enhancement Ratio (OER)?
2
197
Given a dose of 2 Gy of standard X-rays with an RBE of 1, what would be the equivalent biological effect if the same dose of protons with an RBE of 2 is delivered?
4 Gy
198
If a dose of 3 Gy of standard X-rays produces a certain biological effect, and a dose of 2 Gy of alpha particles with an RBE of 3 is delivered, what would be the equivalent biological effect?
6 Gy
199
Which of the following statements is correct regarding the decay constant (λ) of a radioactive material?
Decay constant is inversely proportional to half-life.
## Footnote
The decay constant (λ) and half-life (T½) are related by the equation λ = ln(2) / T½. Therefore, as the half-life increases, the decay constant decreases, and vice versa.
200
If a radioactive substance has an initial activity of 400 MBq and a half-life of 20 hours, what will be its activity after 60 hours?
50 MBq
## Footnote
After 60 hours, three half-lives have passed (60 hours / 20 hours per half-life). The activity reduces to (1/2)^3 = 1/8 of the initial activity. Therefore, 400 MBq / 8 = 50 MBq.
201
How do sulfhydryls primarily function as radioprotectors in the context of radiation therapy?
Acting as antioxidants and scavenging free radicals
## Footnote
Sulfhydryls act as radioprotectors by serving as antioxidants. They neutralize free radicals generated by ionizing radiation, preventing cellular damage.
202
Which radioprotector is often utilized to minimize radiation-induced damage in patients undergoing radiation therapy for head and neck cancers?
Amifostine
203
What contributes to overall radiation safety in handling and disposing of radioactive materials in brachytherapy?
Adherence to strict protocols
204
When utilizing a CT simulator for treatment planning, what actions should the radiation therapist take to guarantee accurate and safe treatment?
Verify patient positioning and alignment during simulation.
205
In the event of a malfunction in the linear accelerator's interlock system during a treatment session, what should the radiation therapist prioritize for patient safety?
Stop the treatment immediately and troubleshoot the interlock issue.
206
During a radiation therapy treatment session, a patient moves unexpectedly. What immediate actions should the radiation therapist take to ensure safe delivery?
Pause the treatment, communicate with the patient, and reposition as necessary.
207
How would you handle a situation where a patient is visibly anxious about the upcoming radiation therapy session?
Provide emotional support, address concerns, and involve the patient in decision-making when possible.
208
How would you react to a fellow radiation therapist who consistently neglects to wear the required protective gear during treatment sessions?
Politely remind the colleague about the importance of wearing protective gear.
209
Which of the following personnel monitoring devices can be used to provide an immediate exposure readout for a radiation worker?
Pocket ion chamber
210
The cumulative effective dose (CumEfD) limit does not include
1. exposure acquired as a consequence of a radiation worker's undergoing medical imaging procedures.
2. radiation exposure from natural background radiation.
3.radiation exposure received while radiation therapists perform imaging procedures on patients.
4.radiation exposure received while radiation therapists perform treatment procedures on patients.
1, 2
211
Patients are monitored during treatment delivery with megavoltage treatment units by using which of the following?
1. closed-circuit television
2. nonverbal communication
3. two-way audio
4. direct visual
closed-circuit television
two-way audio
212
Which of the following is NOT safe to bring into an Magnetic Resonance (MR) environment? (Checkboxes - you may select one or more answers)
keys
wedding or engagement ring
cell phone
credit cards, hotel key cards, passports
all of the above
213
Where are "beam on" lights are located? (select all that apply)
1. mechanical indicator
2. treatment unit
3. at entrance door
4. control panel
all but 1
214
Which of the following are electromagnetic radiation? (select all that apply)
1. alpha particles
2. x-rays
3. gamma rays
4. electrons
2 and 3
215
The concept of effective dose accounts for the __________________.
different types of radiation and RBE
relative radiosensitivity of various tissues and organs
216
How does fractionation in radiation therapy contribute to managing radiation tissue tolerance?
It increases the protracted days
It increases the total radiation dose delivered to tissues
It minimizes the risk of tissue damage
217
Which of the following tissues contain cells that do not divide?
Nervous tissue in an adult
Muscle tissue in an adult
218
Consider a scenario where a linear accelerator shows an unexpected deviation in radiation output during a routine quality check. What steps would you take to analyze and rectify the issue?
Document the deviation
Immediately halt all treatments
219
Which factors influence the radiosensitivity of tissues in radiation therapy?
Biological factors of tissue
Physical factors of radiation
Chemical factors of tissue
