Procedures Exam Flashcards
1
Q
Which of the following is (are) true when the linear accelerator is in the electron beam mode?
a) A flattening filter is required to make the electron beam profile symmetric and flat
b) b and c
c) There is interaction with the transmission target before leaving the exit window
d) a, b, and c
e) A scattering foil is required to make the electron beam profile symmetric and flat
A
A scattering foil is required to make the electron beam profile symmetric and flat
e)
2
Q
The electron gun is similar to what part of a diagnostic x-ray tube?
A
Cathode
3
Q
In treatments using kilovoltage equipment, filters are used to ___________________.
A
filter low-energy x-rays
4
Q
Of the following treatment units, which has the least amount of skin sparing?
A
Orthovoltage
5
Q
Orthovoltage x-ray machines have energies in the range of which of the following?
A
150 kV to 500 kV
6
Q
Lipowitz metal is composed of which of the following?
A
Tin, bismuth, lead, and cadmium
7
Q
Depth of maximum dose for a 10 MV beam is ______ below the skin surface.
A
2.5 cm
8
Q
Depth of maximum dose for a 6 MV beam is _____ below the skin surface.
A
1.5 cm
9
Q
Depth of maximum dose for a 15 MV beam is _________ below the skin surface.
A
3 cm
10
Q
Depth of maximum dose for a 18 MV beam is _________ below the skin surface.
A
3.5 cm
11
Q
Which of the following two-field arrangements is considered parallel opposed?
A
Field 1 gantry = 310; Field 2 gantry = 130
12
Q
With higher radiation exposure to the patient during a computed tomography examination, there is
A
an increased associated cancer risk.
13
Q
In CT because of higher effective energy of the x-ray beam, both ____________ and _______________ interactions contribute substantially to the image.
A
photoelectric; Compton
14
Q
Computed tomography images of the plane of the body perpendicular to the long axis of a patient are termed
A
axial images.
15
Q
In CT when a series of adjacent slices is obtained, some radiation will also scatter from the slice being made into the adjacent slices. What is this radiation called?
A
Interslice scatter
16
Q
______________ is the ratio between the movement or advancement of the patient couch and the x-ray beam collimator dimension.
A
Pitch
17
Q
The two principal characteristics of a medical image are _______________________.
A
spatial resolution and contrast resolution
18
Q
Recent studies have shown that denser breast tissue is best imaged with _____________________.
A
digital mammography
19
Q
As mAs is increased the signal-to-noise ratio is ____________.
A
increased
20
Q
Image detail is also called _______________________.
A
spatial resolution
21
Q
With digital imaging, patient dose can be reduced by using higher _________ techniques.
A
kVp
22
Q
A CT scanner specifically designed for use in the radiation therapy department should have which characteristics?
I. High performance scanner
II. Laser and patient marking system
III. Virtual simulation capabilities
A
I, II, and III
23
Q
Which of the following are benefits of CT simulation?
I. The ability to outline critical structures and view these structures in three dimensions
II. Machine setup parameters and treatment accessories unable to be verified on the CT scanner
III. Virtual simulation allows for construction of digitally reconstructed radiographs DRRs without the patient being present
A
I and III
24
Q
Which of the following is the window width on a CT image?
A
The range of numbers displayed on a CT image
25
Which of the following is the window level on a CT image?
The central Hounsfield unit of all the CT numbers displayed on an image
26
Image registration or fusion has all of the following characteristics except which of the following?
It ensures that the patient is in the same position for all scans.
27
A contraindication for administering barium-based contrast to a patient with a history of long-term steroid therapy would be an increased risk of _______________.
colon perforation
28
When using intravenous (IV) contrast to enhance the anatomy of the brain, the best interval for contrast administration should be before the scan by _____________.
30 minutes
| 10-30 min
29
Each CT projection records variations in _________________________.
mass density and effective atomic number
30
Each CT projection is ________________________.
stored on the computer
31
The cross-sectional anatomy is translated into ___________ during CT reconstruction.
a matrix of values
32
The patient dose in CT is determined by the ________________ collimator.
prepatient
33
The time from the end of CT imaging to image appearance is called the ______ time.
reconstruction
34
Each pixel of information in the CT image contains numerical information in ___________ units.
Hounsfield
35
The pixel size is reduced when the _______ size is increased and the _____________ size is fixed.
matrix, field of view
36
The CT scanner must be calibrated so that ____________ is at CT number zero.
water
37
Image noise in CT scanning depends on _______________________.
pixel size
detector efficiency
slice thickness
38
Iodine-125 (125I53) has been used quite extensively since 2000 in the form of titanium-encapsulated cylindrical seeds to give a tumoricidal radiation equivalent dose to tumors of what kind?
cancers that are confined within the prostate gland.
39
Tellurium-125 (125Te52) has
52 protons and 73 neutrons.
40
What is the half-life of Technetium-99m?
6 hours
41
In __________, a neutron transforms itself into a combination of a proton and an energetic electron.
beta decay
42
Diagnostic techniques in nuclear medicine typically make use of ___________ radioisotopes as radioactive tracers.
short-lived
43
Gamma rays differ from x-rays
only in the method of how they are produced.
44
A solid encapsulated radioactive source
is never to be touched directly with the hands; instead long tongs which add distance should be used.
45
The best definition of the term prognosis is the:
predicted outcome or likelihood of recovery from a specific disease.
46
Which of the following is considered a systemic sign of disease?
Fever
Swelling of the knee
Red rash on the face
Pain in the neck
Fever
47
Etiology is defined as the study of the:
causes of a disease.
48
A change in a tissue marked by cells that vary in size and shape and show increased mitotic figures would be called:
dysplasia
49
When a group of cells in the body dies, the change is called:
necrosis
50
The term cancer refers to:
malignant neoplasm.
51
A collection of signs and symptoms, often affecting more than one organ or system, that usually occur together in response to a certain condition is referred to as a (an):
syndrome
52
A collection of signs and symptoms, often affecting more than one organ or system, that usually occur together in response to a certain condition is referred to as a (an):
syndrome
53
What is a benign neoplasm originating from adipose tissue called?
Lipoma
54
What are malignant neoplasms arising from connective tissue cells called?
Sarcomas
55
Which of the following is a characteristic of a benign tumor?
Cells appear relatively normal.
56
Which factor provides the basis for the grading of newly diagnosed malignant tumors?
Degree of differentiation of the cells
57
A warning sign of possible cancer would be any of the following EXCEPT:
sudden development of fever, nausea, and diarrhea.
58
The common local effects of an expanding tumor mass include:
1. obstruction of a tube or duct.
2. anemia and weight loss.
3. cell necrosis and ulceration.
4. tumor markers in the circulation.
1, 3
59
Which of the following does paraneoplastic syndrome refer to?
The effects of substances such as hormones secreted by the tumor cells
60
Which term refers to the spread of malignant cells through blood and lymph to distant sites?
Metastasis
61
One reason for staging a malignant tumor at the time of diagnosis is to:
determine the best treatment and prognosis.
62
The process of carcinogenesis usually begins with:
an irreversible change in the cell DNA.
63
Radiation therapy destroys:
primarily rapidly dividing cells.
64
Chemotherapy usually involves a combination of drugs in order to:
1. reduce the adverse effects.
2. guarantee that all cancer cells are destroyed.
3. be effective in more phases of the cell cycle.
4. totally block the mitotic stage.
1, 3
65
Why does ovarian cancer have a poor prognosis?
Specific signs rarely appear until after secondary tumors have developed.
66
Antiangiogenesis drugs act on a malignant tumor by:
reducing blood flow and nutrient supply to tumor cells.
67
The development of neutropenia during chemotherapy for cancer means:
the patient is at high risk for infection.
68
What type of normal cells are often damaged during chemotherapy and radiation treatments?
Epithelial cells
69
High risk factors for cancer include:
1. human papilloma virus.
2. chronic irritation and inflammation.
3. repeated sun exposure.
4. high family incidence.
1, 2, 3, 4
70
The term apoptosis refers to:
programmed cell death.
71
The warning signs for cancer include:
unusual bleeding
change in a wart or mole (e.g., color)
a new solid lump, often painless.
All the above
All the above
72
A classification process that applies to a specific malignant tumor and describes the extent of the disease at a given time is called:
staging.
73
Benign tumors can often be differentiated from malignant tumors because benign tumors:
are encapsulated and slow-growing.
74
Benign tumors in the brain are often life-threatening because they:
create excessive pressure within the skull.
75
The method that can be used as an alternative to surgical removal of a tumor by using heat generated by a needle inserted into the tumor is referred to as:
radiofrequency ablation.
76
Staging systems used to classify a malignant tumor at the time of diagnosis are based on which of the following factors?
Size of the tumor, involvement of lymph nodes, metastases
77
One of the general effects of a malignant cancer is cachexia, which is:
severe tissue wasting.
78
Which of the following treatment positioning techniques are most frequently used when localizing the bladder?
I. supine positioning III. full bladder
II. prone positioning IV. empty bladder
I and IV
79
Dose rate for a linear accelerator is expressed as:
cGy/MU
80
As beam quality increases, depth of maximum dose ______:
increases
81
Determine the equivalent square for a rectangular field with a width of 7cm and a length of 17cm
9.9cm2
## Footnote
2(7*17)/(7+17)=9.9
82
Percentage depth dose tables are most often used when calculating the dose for which portal arrangement?
single open field
| SSD technique is most often used for single open fields
83
Convert 2 Gy into cGy
200 cGy
84
SAD is measured from the source to the:
isocenter
85
Geometric definition of the position and extent of the tumor or anatomical structures by reference of surface marks that can be used for treatment setup is termed:
localization
86
The final check done by a radiation therapist to ensure the planned treatment beam covers the tumor or target volume is termed _______:
verification
87
Measurement of a patient’s thickness along the central axis is called the:
IFD
88
The isocenter is:
the point around which the source of the beam rotates
89
Determine the equivalent square for a rectangular field with a width of 8cm and a length of 15cm
10.4cm2
90
Calculate the equivalent square of a 12 x 12cm field with a 2 x 6cm block.
11.5
91
Keeping all other factors the same percentage depth dose ________ with decreasing energy.
Decreases
92
Keeping all other factors the same, TMR ________ with increasing energy.
Increases
93
Keeping all other factors the same percentage depth dose ________ with increasing depth in tissue.
Decreases
94
Keeping all other factors the same percentage depth dose ________ with increasing SSD.
Increases
95
Keeping all other factors the same, TMR ________ with increasing depth in tissue.
Decreases
96
What is the most common unit of measure of equivalent dose?
Millisievert
97
In therapeutic radiology what SI units are now routinely used to specify absorbed dose?
Gray and centigray
98
Which of the following defines Dmax?
Depth of maximum equilibrium
99
If an atom has more protons than electrons it will:
have a positive charge
100
Except for the K shell, the maximum number of electrons that can be in the outermost shell of an atom is:
8
With the exception of the K shell, no more than 8 electrons can be in the atom's outermost shell.
101
An atom of helium (42He) has:
two protons
102
The inverse square law relates the intensity (of light/x-rays) to:
distance
103
Which of the following is an advantage of a source-to-axis distance treatment compared to a source-to-skin distance treatment?
Table adjustments between fields are not normally required
104
The relationship between field size and distance from the source of radiation is ___________ proportional.
directly
105
An 8 cm x 12 cm mediastinum field is treated to a depth of 3cm on a 6MV unit to 200 cGy/fx. What is the spinal cord dose if the cord is located 8cm deep. The output is 200 cGy/min at dmax.
Depth----PDD
1.5-------100
3.0------90
5.0-----85
8-----63
140
106
A high energy gamma source requires 4mm of copper to reduce the original intensity by 50%. This source has a half-value layer of:
4mm copper
107
All of the following apply to “absorbed dose” except:
can be measured using ionization chambers
energy deposited at a point
measured in Gy
measured in air
measured in air
108
1 Gy is equal to:
1J/kg
109
Mayneord F factor is used in:
SSD setups when increase your distance
110
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
111
The intensity of a radioactive beam is measured at a distance of 100 cm and found to be 250 mR/min. What will the intensity of this beam be at 105 cm?
226.8 mR/min
112
Absorbed dose at depth x 100% = absorbed dose at Dmax is the definition of:
PDD
113
Absorbed dose at a given depth divided by the dose in air dose at a fixed reference is the definition of:
TAR
114
A TAR at the depth of Dmax used to correct for scatter of dose is called the _________.
backscatter factor
115
The equivalent square of rectangular field of 10 x 15 is:
12 x 12
116
The equivalent square of rectangular field of 20 x 10
13.3 x 13.3
117
A wedge filter is used to alter the isodose distribution on an anterior chest field. The MU setting must be ________________ to account for the wedge filter in the field.
increased
118
The physician prescribes the AP/PA field to be weighted 3:1 for the posterior field. How much dose is coming from the AP and the PA if total dose prescribed is 200 cGy?
AP = 150 cGy, PA = 50 cGy
119
Calculate the PDD of depth (d) if the dose at Dmax is 180 cGy and the dose at d is 127 cGy.
70.6%
120
Calculate the PDD of depth (d) if the dose at Dmax is 250 cGy and the dose at d is 231 cGy.
92.4%
121
A patient is treated using two superiorly/inferiorly adjacent fields. The collimator setting for the superior field is 10 cm wide by 13 cm long. The collimator setting for the inferior field is 20 cm wide by 35 cm long. Both fields are treated at 100 cm SSD. Calculate the gap at the skin surface if the fields abut at a depth of 5 cm.
1.2
122
Adjacent fields that have an overlap at depth due to divergence are called:
abutted fields
123
When blocking is used in a treatment calculation, the area of the collimator is used in determining:
TMR
OUTPUT FACTOR
PDD
output factor only
124
Which of the following is not a tissue absorption factor?
1. TMR 2. Output Factor 3. PDD
2 only
125
Two parallel opposed equally weighted 6-MV fields are separated by 20cm of tissue and treated with an SSD technique. The maximum dose will occur:
1.5cm under the skin surface
126
Mayneord’s factor is used to convert:
PDD with a change in SSD from the standard
127
In a fixed SSD technique, the dose is routinely normalized:
at Dmax
128
In an isocentric treatment technique, the dose is routinely normalized:
at the isocenter
129
The field size when using an SSD technique and a photon beam is usually defined:
on the skin surface
130
The angle of beam divergence is:
larger farther from the CAX
131
TAR is dependent upon:
Energy 2. SSD 3. depth 4. field size
1,3 and 4
132
Which beam would produce the maximum amount of backscatter:
1.25 MV
133
The %DD for a 12 x 12cm field, 4MV photon beam, 5cm depth, and 80cm SSD is 82.8. Calculate the % DD for the same field size and depth for 100cm SSD.
84.3
134
If the field size indicator is set for 20 x 20 cm at 80 cm SSD, what is the field size at 84cm?
21 x 21 cm
135
If a Co-60 unit is used at 80cm SSD for a 15 x 15cm field size and has a %DD of 58.4 at 10cm depth, what is the %DD for the same field size and depth at 100cm SSD?
60.9
136
The counterpart of the timer setting of a Co-60 unit is most similar to the ____ of a LINAC.
monitor unit
137
A patient is being treated with a 6MV photon beam using an SSD technique. The prescribed dose is 180 cGy at a depth of 8 cm. The treatment is delivered at a source-to-skin distance (SSD) of 100 cm. The field size is 15 cm x 15 cm. Calculate the MU required for this treatment.
Reference Dose Rate: 1 cGy/MU
Output: 1.02 cGy/MU
Percent Depth Dose (PDD): 88.1%
Tissue Maximum Ratio (TMR): 0.78
Tray Factor: 0.98
Wedge Factor: 1.15
200
| 180/(1.02*.881)= 200.31
138
A patient is being treated with a 15MV photon beam using evenly weighted parallel opposed fields. The prescribed dose is 250 cGy to the isocenter. The treatment is delivered at a source-to-axis distance (SAD) of 100 cm.The depth to the isocenter is 10 cm. The field size is 10 cm x 12 cm, with a portion of the field blocked by a custom block resulting in a 8cm x 10cm open field. Calculate the MU per beam.
Reference Dose Rate: 1 cGy/MU
Collimator scatter factor (Sc): 1.03
Patient scatter factor (Sp): 0.97
Percent Depth Dose (PDD): 68.2%
Tissue Maximum Ratio (TMR): 0.81
Tray Factor: 0.99
Wedge Factor: 1.00
163
| 125 ÷ ( 1.03 × .97 × 0.81 × 0.99 ) = 162.7
139
Which of the following is true regarding portal imaging in radiation therapy?
The primary photon interaction is from Compton scatter.
140
A patient is being treated with a 10MV photon beam using evenly weighted parallel opposed fields. The prescribed dose is 300 cGy to the isocenter. The treatment is delivered at a source-to-axis distance (SAD) of 100 cm. The depth to the isocenter is 8 cm.
Field 1: The field size is 12 cm x 12 cm. A custom block is used, reducing the field to 11 x 11 cm.
Field 2: The field size is 12 cm x 12 cm. No block is used. A 45-degree wedge is used.
Reference Dose Rate: 1 cGy/MU
Collimator scatter factor (Sc) 12 x 12 cm: 1.02
Patient scatter factor (Sp) 12 x 12 cm: 0.98
Patient scatter factor (Sp) 11 x 11 cm: 0.97
Tissue Maximum Ratio (TMR) 12 x 12 cm: 0.85
Tissue Maximum Ratio (TMR) 11 x 11 cm: 0.84
Tray Factor: 0.99
Wedge Factor: .925
Field 1: 182 ; Field 2: 191
Field 1: MU = 150 cGy / (1 * 1.02 * 0.97 * 0.84 * 0.99) = 182.3
Field 2: MU = 150 cGy / (1 * 1.02 * 0.98 * 0.85 * 0.925) = 190.85
141
Digitally reconstructed radiographs (DRRs) contain _____ information and are considered _____ images.
isocenter, beam's eye view
142
The number of images generated by a computed tomography (CT) scan is determined by the _____ of each slice.
thickness
143
The radiation therapist should check the gantry _____ after the table has been offset to eliminate a possible collision.
clearance
144
Radiation oncology goals include all of the following except:
increase toxic effects
ensure precise dose delivery
reduce side effects
achieve optimal treatment accuracy
increase toxic effects
145
The tilting of an isodose curve from its normal position is best accomplished by the use of:
wedge filters
146
When treating to a depth of 5cm using partial arc therapy the isocenter should be placed at:
2.5cm
5.0cm
7.0cm
1.5cm
7.0cm
147
A lesion is being treated using an arc of 100º. If the midpoint of the tumor volume is at 7cm, the isocenter should be placed at:
7cm
3.5cm
10.5cm
1cm
10.5cm
148
When using parallel opposed fields, if the gantry is rotated 180º for the opposing field:
the collimator rotation must be reversed
149
The movement of the field matching point will help to:
improve the dose uniformity near the skin surface
150
Which of the following has no units?
Relative Biological Effectiveness
151
Arrange 4 kev electrons, 4 MeV electrons and 20 MeV electrons in increasing order of their ability to penetrate tissue.
4 kev, 4MeV, 20MeV
152
Radiation therapists and radiation oncologists prefer the kV images because the _______________________.
contrast is better
153
What is the tumor staging system for breast cancer?
TNM
154
What is the tumor staging system for lung cancer?
TNM
155
Which of the following management strategies is least likely to be used in the management of a patient with prostate cancer?
Chemotherapy
156
The Gleason system assigns a value based on the ____ of malignant cells.
grade
157
The staging system employed for most gynecologic tumors is:
FIGO
158
Xerostomia is caused by irradiation of the:
salivary glands
159
All of the following are major etiologic factors of head and neck cancer except:
poor dental hygiene
handwashing
alcohol consumption
smoking
handwashing
160
BID radiation therapy is a form of:
hyperfractionation
161
All of the following are considered simple immobilization devices except:
thermoplastic mask
162
_________________complex immobilization devices, such as thermoplastic immobilization devices and foaming agent devices, to the treatment couch will provide for “tighter” tolerance settings.
Indexing
163
A(n) __________ is a reproduction of an external body shape, usually taken through the transverse plane of the CA of the treatment beam.
contour
164
_______________________ contours are the most accurate of all transverse contouring methods.
CT-generated
165
Of the four desired qualities of a CT image, which refers to the ability to see shades of gray in tissue?
image contrast
166
An MRI reveals a brain lesion predominately on the right side of the brain. The MD has prescribed 3000cGy using POP fields with the right side delivering two times the left. What is the dose delivered from the left lateral field?
1000 cGy
167
An MRI reveals a brain lesion predominately on the right side of the brain. The MD has prescribed 3000cGy using POP fields with the right side delivering two times the left. What is the dose delivered from the right lateral field?
2000 cGy
168
A dose of 3000 cGy is to be delivered at a depth of 8cm at a percent depth dose of 76%. What is the dose to an organ at 14cm depth and a percent depth dose of 58%?
2289 cGy
169
What is the given dose for a patient receiving 250 cGy a day treated at 5cm depth with SSD technique, if the %DD is 84.5%?
296
170
A patient was treated in 2008 via a 5cm x 18cm PA spine field at 100cm SSD. She has returns and needs an adjacent area of the spine treated. The new field is 23cm long at 80cm SSD. What is the skin gap necessary to match the fields at 5.5cm depth?
1.29cm
171
Electrons are useful in radiotherapy treatment to a maximum practical range of:
7cm
172
If a 30 degree wedge is left out of the treatment by mistake:
the central axis dose is increased and the isodose distribution is affected
173
Central axis depth dose distribution depends on beam energy. Which of the following is true?
depth of a given isodose curve increases with beam quality
174
The principal advantage to the use of an electron beam is a:
rapid buildup of dose at the skin surface
175
The electron density of compact bone will have a value of about __ when compared to that of muscle or water.
1.65
176
_______ corrections account for the dose effects produced by the presence of materials of density different than water or unit density:
heterogeneity
177
in treatment planning, when dose delivery parameters are computed based on target-dose delivery and normal-tissue avoidance criteria, the process is termed ______ planning:
inverse
178
IMRT is a treatment planning and delivery process that seeks to achieve treatment plan optimization by varying the ____ of the treatment beams in addition to their position:
intensity
179
Image _____ is a process by which images produced by different modalities can be combined to use the best features of each modality:
fusion
180
Annihilation radiation is used in which of the following modalities?
Positron emission tomography (PET)
181
Respiratory motion can be managed by which of the following?
I. Rapid CT scanning
II. 4DCT
III. Two–breath-hold CT
II and III
182
A single fraction of radiation to a brain metastasis would be what kind of stereotactic treatment?
Stereotactic radiosurgery (SRS)
183
Which processes are responsible for electron interactions with matter?
I. Collisional processes
II. Radiation processes
III. Gradient processes
I and II
184
What is the practical range of a 25-MeV electron beam?
12.5 cm
185
What is the depth of the 80% isodose line of a 15-MeV electron beam?
5 cm
186
What is the depth of the 90% isodose line of a 9-MeV electron beam?
2.25 cm
187
Which electron beam energy is most likely to under-dose at the surface?
12 MeV
16 MeV
9 MeV
20 MeV
9 MeV
The region from the surface to the depth of maximum dose is at risk for being under-dosed in many clinical situations. This is most true for lower-energy electron beams (less than 12 MeV).
188
What thickness of lead is necessary to adequately shield a 9-MeV electron beam?
4.5 cm
189
What thickness of Lipowitz alloy is necessary to adequately shield a 9-MeV electron beam?
5.4 cm
190
The carina is located at:
T4 to T5, sternal angle.
191
What is (are) spatial representation(s) of the magnitude of the dose produced by a source of radiation?
Dose distributions
192
What determines the hinge angle?
| The angle between two beams' central axes that share an isocenter
193
Which type of IMRT treatment involves the “sliding window” technique?
Dynamic MLC
194
In the convolution algorithm, primary fluence is represented by what symbol?
y(r)
195
The internal target volume (ITV) is the __________.
CTV + IM
196
Tumor-suppressor genes are also known as ___________.
anti-oncogenes
197
Which of the following is true of anaplastic tumors?
Do not resemble the cells of origin
198
What is the “workup”?
A series of diagnostic examinations
199
A T1N0MX tumor has how many positive lymph nodes?
0
200
Which of the following are not cell-cycle specific?
I. Alkylating agents
II. Antimetabolites
III. Antibiotics
IV. Hormonal agents
V. Nitrosoureas
VI. Vinca alkaloids
I, III, and V
201
Which class of chemotherapy agents is derived from the periwinkle plant?
Vinca alkaloids
202
In which class are chemotherapy agents lipid-soluble and capable of crossing the blood-brain barrier?
Nitrosoureas
203
Which of the following is a radio-sensitizing chemotherapy agent?
Doxorubicin
| also known as Adriamycin
204
A cancer designated with an N1 classification using the TNM staging system likely indicates which of the following?
Positive lymph nodes are involved near the site.
205
In radiation therapy planning, why is it crucial to define the ITV (Internal Target Volume) in addition to the CTV and GTV?
The ITV accounts for physiological movements of the target during treatment, such as breathing or peristalsis.
206
A patient's isocenter was moved due to new clinical findings. What should be the appropriate adjustments made by the radiation therapist?
Recalculate monitor units, recontour to include new areas included in the field.
207
A spinal cord compression at the level of T5-T6 is being treated emergently. The most likely field arrangement would be:
A single posterior photon field.
208
Assuming the patient is positioned supine with the head into the gantry, referencing an axial image view, a shift from the isocenter should be:
lsocenter X -1.0cm
lsocenterY +1.0 cm
Isocenter Z -2.0 cm
1.0 cm to the patient's right
209
Which of the following methods may reduce the dose to the small bowel during radiation therapy? (select two)
Empty bladder
Supine positioning
Full bladder
Prone positioning
full bladder
prone positioning
210
To avoid beam divergence from the tangential fields into the supraclavicualr field, which of the following methods can be used? (select two)
The foot of the couch is turned toward the collimator.
The head of the couch is turned away from the collimator.
Use asymmetrical collimators and a single isocenter
The foot of the couch is turned away from the collimator.
Use asymmetrical collimators and a single isocenter
The foot of the couch is turned away from the collimator.
211
Which of the following are included in the radiation therapy prescription? (Choose all that apply)
number of treatments
monitor units
beam-shaping devices
frequency of treatment
beam energy
dose per treatment
tumor dose
treatment volume
all but monitor units
212
Which of the following are forms of portal imaging? (select two)
1. radiographs
2. respiratory gating
3. electronic portal imaging devices (EPID)
4. kv surface imaging
radiographs
electronic portal imaging devices
213
Radiation therapists must be able to identify which of the following: (select three)
1. the location of a tumor
2. organs in close proximity to a tumor
3. findings of post-treatment imaging studies
4. effects of patient movement on a tumor
the location of a tumor
organs in close proximity to a tumor
effects of patient movement on a tumor
214
Which of the following modalities create tight dose constraints around the tumor volume, allowing surrounding tissue to be spared more easily? (select two)
1. electron setup
2. intensity modulated radiation therapy
3. 2d radiation therapy
4. volumetric modulated arc therapy
2 and 4
