CT - PRELIM L2 & L3 Flashcards
1
Q
Most prominent part of a CT scanner characterized as a circular rotating frame with an x-ray tube mounted on one side and a detector on the opposite side
A
Gantry Assembly
2
Q
Opening in the gantry of a CT scanner through which the patient is positioned for scanning
A
Gantry Aperture
2
Q
The Gantry Assembly is also known as _________
A
Doughnut Shape Equipment
2
Q
The size of the aperture varies depending on the model
of the CT scanner, but it generally needs to be ________
enough to accommodate the body part being imaged.
A
Large
3
Q
General diagnostic CT scanners have gantry apertures measuring ________
A
50-80 cm (20”-34”)
4
Q
Dedicated machines such as radiation therapy CT scanners have gantry apertures measuring _______
A
100 cm (39.3”)
5
Q
A _______ aperture might be ideal for high-resolution scans of specific areas (such as the BRAIN or HEART)
A
Smaller
6
Q
The size of the aperture must be balanced with _______, ensuring that the patient feels at ease during the scan
A
Patient Comfort
7
Q
Precision in aperture size is important for ensuring
accurate imaging.
A
Scan Quality
8
Q
The X-ray tube used in a CT scanner (computed tomography scanner). It is a critical component that generates X-rays, which are used to create cross- sectional images of the body.
A
CT Tube
9
Q
This CT tube has a stationary anode with 2mm x 16 mm focal spot with 120 kVp and 30 mA
A
80x80 Matrix Display
10
Q
This CT tube has a rotating anode with 0.6 mm x 1.2 mm focal spot with selectable kVp (80, 120, 140), 1000 mA, and 0.5-5 million heat units thermal capacity
A
512x512 Matrix Display
11
Q
It helps capture the X-ray data that is used to create cross-sectional images (slices) of the body
A
CT Scan Detector
12
Q
Efficiency to receive
photons. Controlled by
detector size and
interspacing
A
Capture Efficiency
13
Q
Efficiency to convert
photons to light or ions. Controlled by detector
material, size and thickness.
A
Absorption Efficiency
14
Q
Efficiency to Convert light or ions to digital signal
A
Conversion Efficiency
15
Q
Detector Dose Efficiency may be calculated with what formula:
A
DDE = CapE + AE + ConE
16
Q
The ability to maintain in a
quality calibrated state.
A
Stability
17
Q
Which detectors arrays are the most stable ?
A
Fixed Detector Arrays
18
Q
The speed of the detector to
react/recognize incoming
x-ray photon and recover for
the next input
A
Response Time
19
Q
The range of x-ray
intensities a detector can
differentiate
A
Dynamic Range
20
Q
A ______ provides the
DISCRIMINATION between
small differences in x-ray
attenuation
A
High Dynamic Range
21
Q
This is a detector that consists of SCINTILLATION CRYSTALS and photomultiplier tube
A
Solid State Detector
22
Q
Which scintillation material has 100 % Absorption Efficiency
A
Sodium Iodide (Nal)
23
What are the scintillation materials used for new Solid State Detectors (5):
1. Calcium Fluoride
2. Bismuth Germinate
3. Cesium Iodide
4. Gadolinium Ceramics
5. Calcium Tungstate
24
Consist of pressurized Gas-Filled (Inert/Noble Gases)
Ionization chambers and tungsten electrode plate
Gas-filled Detectors
25
What are the elements in Group 18 of the Periodic Table that may be considered as Inert or Noble gases (6):
1. Helium
2. Neon
3. Argon
4. Krypton
5. Xenon
6. Radon
26
TRUE OR FALSE
Gas-filled Detectors may be used in 4th,5th, 6th, and 7th CT Scanners
FALSE
Gas-filled Detectors CANNOT BE USED in 4th,5th, 6th, and 7th CT Scanners
27
A device used to
control and shape the X-ray beam as it exits the X-ray
tube.
Collimator
28
The collimator shapes the
X-ray beam to match the
area of the body being
scanned. This ensures
that the X-rays are
directed only to the
specific region of interest, helping to minimize
exposure to surrounding
tissues
Beam Shaping
29
This is unwanted radiation that can bounce off tissues and create noise in the image
Scatter Radiation
30
By restricting the X-ray
beam to the area being
scanned, the collimator
ensures that only the
targeted body area
receives radiation,
thereby __________ to
the patient.
Minimizing Radiation Dose
31
Located between the X-ray tube and the patient, this
collimator helps to shape the X-ray beam before it
interacts with the body.
Pre-Patient Collimator
32
Located after the patient, this collimator controls the X-rays that pass through the body and reach the detector, helping eliminate any scattered x-rays that might contribute to noise or artifacts in the image
Post-patient Collimator
33
This refers to the circular movement of the X-ray tube
and the detector around the patient’s body, allowing the scanner to take multiple x-ray images from different angles.
Rotate
34
This refers to the linear movement of the X-ray tube
and detector along the body.
Translate
35
A Curved patient couch is ideal for _______
General Radiography
36
Low Z materials for patient couch is often made of ______
Carbon Fiber Graphite
37
A ________ patient couch is ideal for Radiation Therapy
Flat
38
Receives raw data from
the detectors and
transmits it to the
processor
Data Acquisition System (DAS)
38
Typical weight capacity of patient couch/table ranges from ______ to _____
150 kg (330 lbs) to 250 kg (550 lbs)
39
The core component responsible for controlling the
entire CT scanning process, as well as processing, reconstructing, and displaying the images produced by
the scanner
CT Scan Computer
40
Manages the processing
power for reconstruction
algorithms and system
control
Central Processor (CPU)
41
Uses mathematical
algorithms to convert raw
data into usable images.
Image Reconstruction Unit
42
Displays images for
radiologists, with
features for image
manipulation and
analysis
Display Workstation
43
Stores images and data
securely, often in a
PACS or cloud-based
system.
Storage System
44
As the X-ray tube rotates around the patient and the
detectors collect the transmitted X-rays, the computer receives this data in the form of raw data also called as _________
Projections
45
Complete the following:
1st Generation CT Scan
* Tube and Detector Movement
* Beam Shape
* Detector
* Tube and Detector Movement = Rotate-Translate
* Beam Shape = Pencil Beam
* Detector = Single Detector, Solid-State
46
Complete the following:
2nd Generation CT Scan
* Tube and Detector Movement
* Beam Shape
* Detector
* Tube and Detector Movement = Rotate-Translate
* Beam Shape = Fan-shaped X-ray Beam (Narrow)
* Detector = 30 Linear Detectors of Solid-State or Gas-filled
47
Complete the following:
3rd Generation CT Scan
* Tube and Detector Movement
* Beam Shape
* Detector
* Tube and Detector Movement = Rotate-Rotate
* Beam Shape = Fan-shaped X-ray Beam (Wide)
* Detector = 250-750 Curvilinear Detectors of Solid-state or Gas-filled
48
Complete the following:
4th Generation CT Scan
* Tube and Detector Movement
* Beam Shape
* Detector
* Tube and Detector Movement = Rotate-Stationary
* Beam Shape = Fan-shaped X-ray Beam (Wide)
* Detector = 600-2000 Fixed Circular Detectors, Solid-State
49
Complete the following:
5th Generation CT Scan
* Official Name
* Tube and Detector Movement
* Beam Shape
* Detector
* Official Name = Electron-beam Computed Tomography
* Tube and Detector Movement = Stationary
* Beam Shape = Fan Beam
* Detector = 600-2000 Fixed Detectors
50
Complete the following:
6th Generation CT Scan
* Official Name
* Tube and Detector Movement
* Beam Shape
* Detector
* Official Name = Helical / Spiral CT Scan
* Tube and Detector Movement = Rotate - Stationary
* Beam Shape = Fan-shaped Beam (Wide)
* Detector = 600-2000 Fixed, Solid State Detectors
51
Complete the following:
7th Generation CT Scan
* Official Name
* Tube and Detector Movement
* Beam Shape
* Detector
* Official Name = 64/128/254 Multi-Slice CT
* Tube and Detector Movement = Rotate-Stationary
* Beam Shape = Fan-shaped Beam (Wide)
* Detector = Multiple Detectors
52
Which CT scanner generation is prone to Ring Artifacts ?
3rd Generation CT Scan
53
Which CT scanner generation is extremely fast and capable of imaging the beating heart ?
5th Generation CT Scan
54
It is the most basic form of CT scanner taking one slice of the body at a time
Single-Slice CT Scanner
55
The X-ray tube continuously rotates around the patient
while they move through the scanner in a spiral motion, frequently used for chest, abdominal, and brain imaging
Spiral (Helical) CT Scanner
55
This is a more advanced CT scanner that uses multiple
rows of detectors (usually 16, 32, 64, or more) to capture multiple slices at once
Multi-Slice CT Scanner
55
Primarily used in dental, ENT (ear, nose, and throat), and orthopedic imaging
Cone-Beam CT Scanner
56
Uses two different X-ray energy levels to create
images, which are then analyzed to differentiate
between materials based on their atomic composition
Dual-Energy CT Scanner
56
PET Scan shows _______ while the CT scan provides ______
PET Scan = Metabolic Activity
CT Scan= Detailed Anatomical Images
57
Combines PET and CT Scanning technology in a single machine
PET-CT Scanner
57
A smaller, more compact version of a CT scanner that
can be moved to different locations, such as in
emergency rooms or intensive care units (ICUs).
Portable CT Scanner
57
A specialized CT scanner that focuses on imaging the
heart and blood vessels; often used to assess CAD, heart function, and abnormalities in the heart's structures
Cardiac CT Scanner
58
Controls the energy level of the X-ray beam, determining its penetration ability.
Kilovolt Peak (kVp)
58
Used in a procedure where CT scans guide the doctor
during surgery or a minimally invasive procedure; providing real-time imaging to help doctors make precise decisions during interventions, such as biopsies or the insertion of stents
Interventional CT Scanner
58
High kVp = ____ Contrast
Low
59
Low kVp = _____ Contrast
High
59
Typical mAs range for CT
100-400 mAs
59
The product of the X-ray tube current (mA) and the exposure time (seconds). It determines the total
radiation dose delivered to the patient and affects image
quality.
Milliampere-Seconds (mAs)
60
TRUE OR FALSE:
Higher kVp provides better
penetration and can result in increased patient dose but
may decrease soft tissue contrast.
FALSE
Higher kVp provides better
penetration and can result in REDUCED patient dose but
may decrease soft tissue contrast.
61
Typical range of kVp in CT
70 - 140 kVp
62
Refers to the thickness of each individual cross- sectional image (or "slice") obtained during the scan
Slice Thicknesss
63
Common slice thicknesses in CT range from ______ to ______
0.5 mm to 5 mm
64
These slices are often used for more routine imaging when fine detail is less critical
Thicker Slices
64
Which type of slice offer higher resolution and better detail, especially for detecting small lesions, fine anatomical structures, or in 3D reconstructions
Thinner Slices
65
The relationship between patient couch movement and
x-ray beam width
Pitch Ratio
66
Pitch Ratio formula is:
Couch Movement each 360 degrees ÷ Beam Width
66
TRUE OR FALSE
High Pitch means Lower Radiation Dose and Lower Image Quality
TRUE
66
TRUE OR FALSE:
Low Pitch means Higher Radiation Dose and Higher Image Quality
TRUE
66
A single square or picture element within a matrix
Pixel
67
The four (4) main factors contributing to image quality are:
1. Spatial Resolution
2. Contrast Resolution
3. Noise
4. Artifacts
67
Measure of how far apart two objects must be before they can be seen as separate details in the image
Resolution
67
Resolution is measured in ________
Line Pairs per Centimeter (lp/cm)
68
Array of numbers arranged in a grid of rows and columns
Matrix
69
Pertains to the added dimension / tissue volume given to a pixel
Voxel
70
Describes the amount of blurring in an image
Spatial Resolution
70
What are the five (5) scan parameters that affect spatial resolution:
1. Focal Spot Size
2. Slice Thickness
3. Display FOV
4. Matrix
5. Reconstruction Algorithm
71
It is the most significant geometric factor contributing to spatial resolution
Detector Aperture Width
71
Ability to differentiate
between small differences in density within the image.
Contrast Resolution
72
Primarily affects contrast
resolution by serving as graininess in the image
Noise
73
Any distortion or error in the image that does not represent true anatomy or pathology of the patient.
Artifacts
74
If a patient cannot or will not hold still, the scan will likely be non - diagnostic.
Patient Factor
75
It is usually dictated by image protocol. As in tomography, the thinner the slice thickness, the better the image recorded detail. Thin-section CT scans, often referred to as high resolution scans, are used to
better demonstrate structures
Slice Thickness
76
Are usually preselected by the computer as part of the scan program, but they can be altered by the technologist.
Scan Time
77
Scan Diameter is also called as _______
Scan FOV
77
The image that appears on the CRT depends on the ______
Scan Diameter
78
Give the seven (7) types of artifacts in CT:
1. Motion Artifacts
2. Metal Artifacts
3. Beam Hardening
4. Partial Volume Artifacts
5. Aliasing Artifacts
6. Ring Artifacts
7. Noise
79
Noise is also known as _______
Quantum Mottle
