Exam 2 Quizlet Flashcards
1
Q
What does not take place when electrons are accelerated from the cathode to the anode
A
the formation of gamma x-rays
2
Q
All of the following affect distortion, except:
A
object color
3
Q
Teleradiology is the practice..
A
in which radiologists remotely interpret medical images and report the results
4
Q
CPT codes are used:
A
to refer to a specific clinical situation
5
Q
With digital radiography, the cosine law applies to:
A
off-axis viewing
6
Q
Iodine is a ___ contrast agent
A
Positive
7
Q
The production of heat in the anode increases directly with ___ x-ray tube current.
A
Increases
8
Q
Photon interacts with an outer shell atomic electron and the photon becomes redirected, or scattered, from its original path without a change in energy is called
A
Coherent scattering
9
Q
What does filtration eliminate from the beam?
A
it eliminates lower energy x-rays
10
Q
List the stages of digital radiographing in order. (3)
A
Capture, Coupling, Collection
11
Q
Bremsstrahlung x-rays have a ___of energies.
A
Range
12
Q
Sharpness of Image Detail describes the
A
ability to see the detail on the image.
13
Q
Visibility of Image Detail is best measured by
A
contrast resolution
14
Q
Bremsstrahlung X-ray energy is ________ proportional to its wavelength.
A
inversely
15
Q
Software computer components include:
A
-bits
-bytes
-words
16
Q
Contrast resolution refers to:
A
ability to distinguish between and to image similar tissues
17
Q
Differential absorption increases as the ___ is reduced.
A
kVp
18
Q
Interaction between the x-ray and the nuclear electric field that causes the x-ray to disappear and that causes two electrons - one positive and one negative - to take its place is:
A
Pair production
19
Q
PAC’s primary use is to:
A
store digital images
20
Q
The bothersome magnification can be minimized by using:
A
larger SID
21
Q
Barium is considered a ___ contrast agent
A
Positive
22
Q
X-ray intensity is __________________ to the square of the distance from the source.
A
inversely proportional
23
Q
Increasing filtration _____________ the average energy of an x-ray beam and x-ray intensity _______________
A
increases; decreases
24
Q
All of the following are subject factors when assessing image quality, except:
A
object position
25
X-ray beam energy can best be identified by:
half value layer
26
When mAs are increased what effects happen (2)
-no effect on energy
-increase intensity
27
When kVp is increased what effects happen (2)
-increase energy
-increase intensity
28
When distance is increased what effects happen (2)
-no effect on energy
-reduce intensity
29
When filtration is increased what effects happen (2)
- Energy
- Intensity
-increase energy
-reduce intensity
30
T or F: Square law is a corollary to the inverse square law
True
31
What characteristic of radiographic quality is improved by using reduced x-ray exposure time?
motion blur
32
The purpose of Digital Imaging and Communications in Medicine (DICOM) is to:
transfer images
33
Scotopic vision is related to:
night vision
34
Annotation:
label the images
35
Window & level:
expand the digital grayscale to visible
36
Magnification function:
improve visualization and spatial resolution
37
Image flip:
reorient image presentation
38
Image inversion:
make white-black & black-white
39
Subtraction (DSA) improves:
Image contrast
40
Pixel shift:
reregister an image to correct for patient motion
41
Region of interest (ROI) determines
average pixel value for use in quantitative imaging
42
Mag Factor is represented by which equation.
SID/SOD = Image Size/Object Size use in quantitative imaging
image size/object size
43
T or F: The IDC codes were developed by the American Medical Association.
False
44
Filters for x-ray beams are typically made from:
aluminum
45
T or F: Image artifacts can typically be minimized through proper alignment.
False
46
What x-rays are produced when an electron ionizes an inner-shell electron or a target atom?
characteristic x-rays
47
x-ray intensity & mAs have a ___ relationship
direct relationship
48
X-ray ___ determins the penetrability of an x-ray beam.
Quality
49
When selecting technique factors, keep exposure time as ___ as possible to ensure ___
High, Penetrability
50
Radiopaque appears gray on a radiograph (T/F)
False
51
The cones are used for __ __
Photopic Vision
52
Photometry is the science of the:
response of the human eye to visible light
53
Flatfielding is used to
reduce noise & improve contrast
54
___ appears darker on a radiograph.
Radiolucent
55
Air, when used as a contrast agent, is considered a ___ contrast agent.
Negative
56
The kVp changes the __ and ___ of an X-ray Emission Spectrum.
Amplitude and Shift
57
The kVp changes the amplitude and shift of an X-ray Emission Spectrum. (T/F)
True
58
High penetrability = High ___________ rays
Quality
59
If the kVp are increased, then the electron kinetic energy will ____________.
Increase
60
What is the result on the image when an anatomic structure is not equally magnified?
distortion
61
T or F: The toe effect results in reduced x-ray intensity to the anode side of the central axi
False (Heel effect)
62
Spatial resolution refers to:
ability to image small objects that have high subject contrast
63
What principle factors influence the shape of the x-ray emission spectrum? (3)
1. Thick target, causing multiple of interactions of projectile electrons
2. Electrons with low KE
3. Added Filtration
64
T or F: Distortion is a misrepresentation of object size & shape on the image
True
65
T or F: The probability of Compton scattering depends on the atomic number of the target atom
False
66
Photopic vision is associated with:
cone vision
67
What is the magnification factor? ___/___
image size/object size
68
The rods are used principally for which of the following?
dim vision
69
Heat production also ___ indirectly with increasing kVp (at least in the diagnostic range).
Decreases
70
All of the following are types of filtration, except:
compounding filters
71
Absorption of an x-ray by ionization is:
Photoelectric effect
72
Hardware computer components include all of the following except:
bits
73
Adaptation of computer technology to mimic the human mind in cognitive activities is _______________.
artificial intelligence
74
When assessing image quality, which of the following would be considered a geometric factor?
image blur
75
T or F: Characteristic x-rays have a range of energies.
False
76
T or F: Characteristic x-rays have precisely fixed energies
True
77
T or F: Image Receptor sometimes referred to a cassette.
False
78
Sthenic:
"strong active"; average patients
79
Hyposthenic:
thin, but healthy appearing
80
Hypersthenic:
big in frame and usually overweight
81
Asthenic:
small, frail, sometimes emaciated, often elderly
82
Process by which very high-energy x-rays can escape interaction with electrons and the nuclear electric field and can be absorbed directly by the nucleus is:
photodisintegration
83
An increase in mAs which increases the number of x-rays produced, ___________ the amplitude of the spectrum.
increase
84
T or F: X-ray quality is the output intensity of an x-ray imaging system.
False
85
If the mAs increase, the number of projectile electrons racing towards the target _____________.
increase
86
Interaction between an X-ray and a loosely bound outer-shell electron that results in ionization and X-ray scattering.
compton scattering
87
In medical imaging, noise results in:
deterioration of the radiographic image
88
Penetrability is:
Ability of X-rays to penetrate deeper in tissue and to be transmitted through the patient to the image receptor
89
Attenuation is:
the reduction in x-ray intensity due to absorption and scattering
90
X-ray intensity is:
the number of x-rays in a useful beam
91
X-ray beam hardening is achieved by:
increasing the number of high-energy X-rays in the
beam by removing the lower-energy non-penetrating x-rays
92
What is the primary purpose of x-ray beam filtration?
to filter low-energy x-rays
93
What is increased by added filtration?
"Effective" energy
94
What x-rays are produced by the slowing down of an electron by the target atom's nuclear field?
Bremsstrahlung X-rays
95
What is the primary function of the x-ray tube?
accelerate electrons from the cathode to the anode
96
___ Hardware is the components of the system that include various input and output devices
Physical
97
Magnification factor equation:
SID/OID
(Image size/objest size)
98
99
T or F: Bremsstrahlung X-rays have precisely fixed energies.
False
100
T or F: The treatment console is typically located inside the linac treatment room with a lead glass barrier
False
101
Which of the following could be used for IGRT? (Select All that Apply) (3)
-CBCT
-kV imaging
-EPID
102
Multi-Leaf Collimators are made of _________.
Tungsten
103
During IGRT, the images are compared __________ treatment to see if changes need to be made.
prior to
104
The drive stand contains all of the following except:
Electron gun
105
A ___________________ is a type of accelerator that accelerates electrons in the vacuum around a circular path.
betatron
106
The modulator cabinet consists of all of the following, except:
water cooling system
107
_______________ allow(s) many components in the gantry and drive stand to operate at a constant temperature.
water cooling system
108
Treatment couches in the treatment room are typically made of:
carbon fiber
109
Electron gun function:
produces electrons and injects them into the accelerator structure
110
Cathode is a:
spherically shaped structure made of a material with a high atomic number
111
Accelerator structure (guide):
accelerates electrons through multiple coupled cavities in a linear fashion
112
Treatment head:
comprised of several components designed to shape & monitor the treatment beam
113
Bending magnet:
magnet system that focuses and directs the electron beam from the accelerating structure toward the treatment head
114
X-ray target:
placed in electron beam to create an x-ray beam
115
Primary collimator:
shapes the beam; sets maximum field size of the beam at isocenter
116
Beam-flattening filter
flattens the x-ray beam exiting the target
117
Scattering foil:
catter electrons to create a uniform beam of electrons for treatment
118
Ion chamber measures (3):
1. Dose
2. Beam Flatness
3. Symmetry
119
Secondary collimators:
jaws of the machine, sets the field of the beam, often asymmetric
120
An orthovoltage unit would produce an energy of:
250 kV (150-500)
121
Which of the following treatment units produces x-rays ranging from 40 -150 kV?
superficial x-ray unit
122
A cyclotron accelerates charged particles outwards from the center of a flat cylindrical vacuum chamber in a _________ pattern.
spiral
123
Which of the following kV x-ray machines would be used to treat a skin cancer less than 1.5 cm thick?
orthovoltage
124
Obliques include all of the following except:
PA
125
A rectum patient setup might be as follows:
prone belly board, arms above head, wedge under ankles
126
The iliac crest are located at _______.
L4
127
A 4-fld box includes:
AP, PA, and laterals
128
Select all of the following that are true of a conventional simulator. (2)
1. 2D
2. Fluoro capability
129
The thyroid and cricoid cartilage are at the level of ________.
C5-C6
130
The kidneys typically fall between ________.
T11-L3
131
When using the conventional simulator, the isocenter is placed _____________.
at the time of sim typically under fluoro
132
Carina is at the vertebral level ___________.
T4-T5
133
A Klystron amplifies __________ (supplied by radiofrequency driver) in machines >10 MV light waves
microwaves
134
What year was the first linear accelerator used clinically?
1952
135
What is the type of planning utilized when beam parameters and modifiers are added the treatment plan first and then the dose distribution is reviewed (often referred to as Trial-and-error Method)?
forward planning
136
A Tomotherapy unit would best be classified as:
helical delivery treatment machnie
137
A standard lung setup would be as follows:
ingboard, Clr B, Upper Vaclok, Arms Up, Wedge Knees
138
The umbilicus falls at __________.
L3-L4
139
AP refers to:
Anterior posterior
140
The advantages of 2D therapy are: (2)
-treatment planning is quick
-can easily start same day
141
The disadvantages of 2D therapy are: (3)
-large treatment fields
-blocking is more time consuming
-more side effects
142
T or F: Tangents are typically used to treat breast cancer
True
143
When respiratory motion is added to the treatment planning it is considered:
4D
144
Sternal Angle of Louis is at the level of _____.
T4-T5
145
The tip of the xiphoid process is at the ________ vertebral level.
T10
146
A typical head and neck setup is as follows:
S-board, Long Mask, Clr C, Arms at sides, Wedge Knees
147
T or F: Different immobilization devices are used for patient positioning when utilizing the conventional simulation.
False
148
The hyoid bone is at the level of __________.
C4
149
Magnetron is a source of microwave power in machines _____Power Level_____.
< or = 10 MV
150
A typical pelvis setup is as follows:
regular pillow, arms on chest, lower vaclok
151
The angle of the mandible is at the level of ______.
C3
152
The spinal cord ends in ____.
L1
153
Arc (or Rotational Therapy)
radiation is delivered while the gantry is rotating in an arc from one set point to another
154
Stereotactic Radiosurgery
high-dose radiation therapy in a single dose, usually cranial tumors
155
Stereotactic Body Radiation Therapy:
high-dose radiation therapy in fractionated doses, usually outside the cranium tumors
156
Field in Field
technique employs small fields, often only a "few centimeters in diameter" with small numbers of monitor units, frequently as few as five; alternative to the use of wedged fields
157
Simultaneous Integrated Boost (SIB)
a differential dose per fraction is delivered to selected sub-regions during the same treatment session, leading to different total nominal doses given to target volumes in the same number of fractions
158
Intensity Modulated Radiation Therapy (IMRT)
advanced version of 3-D planning creating a nonuniform radiation beam allowing a better dose to the tumor while sparing more organs at risk (OAR)/normal tissue
159
Step and Shoot (Static IMRT)
the beam is delivered with MLC's in a stationary position, turned off as the MLC's move to the next segment, and then turned back on
160
Sliding Window (Dynamic IMRT)
the beam remains on as the MLC's & gantry move throughout the treatment
161
Volumetric modulated arc therapy (VMAT)
the beam is continuously delivered while the gantry & MLC's are both in motion
162
The dome (top) of the diaphragm is considered to be at _______.
T9
163
The treatment blocks are drawn on ____________.
Films
