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COMPUTED TOMOGRAPHY > CT - PRELIM L2 & L3 > Flashcards

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

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2
Q

Opening in the gantry of a CT scanner through which the patient is positioned for scanning

A

Gantry Aperture

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2
Q

The Gantry Assembly is also known as _________

A

Doughnut Shape Equipment

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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

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3
Q

General diagnostic CT scanners have gantry apertures measuring ________

A

50-80 cm (20”-34”)

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4
Q

Dedicated machines such as radiation therapy CT scanners have gantry apertures measuring _______

A

100 cm (39.3”)

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5
Q

A _______ aperture might be ideal for high-resolution scans of specific areas (such as the BRAIN or HEART)

A

Smaller

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6
Q

The size of the aperture must be balanced with _______, ensuring that the patient feels at ease during the scan

A

Patient Comfort

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7
Q

Precision in aperture size is important for ensuring
accurate imaging.

A

Scan Quality

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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

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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

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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

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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

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12
Q

Efficiency to receive
photons. Controlled by
detector size and
interspacing

A

Capture Efficiency

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13
Q

Efficiency to convert
photons to light or ions. Controlled by detector
material, size and thickness.

A

Absorption Efficiency

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14
Q

Efficiency to Convert light or ions to digital signal

A

Conversion Efficiency

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15
Q

Detector Dose Efficiency may be calculated with what formula:

A

DDE = CapE + AE + ConE

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16
Q

The ability to maintain in a
quality calibrated state.

A

Stability

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17
Q

Which detectors arrays are the most stable ?

A

Fixed Detector Arrays

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18
Q

The speed of the detector to
react/recognize incoming
x-ray photon and recover for
the next input

A

Response Time

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19
Q

The range of x-ray
intensities a detector can
differentiate

A

Dynamic Range

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20
Q

A ______ provides the
DISCRIMINATION between
small differences in x-ray
attenuation

A

High Dynamic Range

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21
Q

This is a detector that consists of SCINTILLATION CRYSTALS and photomultiplier tube

A

Solid State Detector

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22
Q

Which scintillation material has 100 % Absorption Efficiency

A

Sodium Iodide (Nal)

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23
Q

What are the scintillation materials used for new Solid State Detectors (5):

A
  1. Calcium Fluoride
  2. Bismuth Germinate
  3. Cesium Iodide
  4. Gadolinium Ceramics
  5. Calcium Tungstate
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24
Q

Consist of pressurized Gas-Filled (Inert/Noble Gases)
Ionization chambers and tungsten electrode plate

A

Gas-filled Detectors

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25
Q

What are the elements in Group 18 of the Periodic Table that may be considered as Inert or Noble gases (6):

A
  1. Helium
  2. Neon
  3. Argon
  4. Krypton
  5. Xenon
  6. Radon
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26
Q

TRUE OR FALSE

Gas-filled Detectors may be used in 4th,5th, 6th, and 7th CT Scanners

A

FALSE

Gas-filled Detectors CANNOT BE USED in 4th,5th, 6th, and 7th CT Scanners

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27
Q

A device used to
control and shape the X-ray beam as it exits the X-ray
tube.

A

Collimator

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28
Q

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

A

Beam Shaping

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29
Q

This is unwanted radiation that can bounce off tissues and create noise in the image

A

Scatter Radiation

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30
Q

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.

A

Minimizing Radiation Dose

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31
Q

Located between the X-ray tube and the patient, this
collimator helps to shape the X-ray beam before it
interacts with the body.

A

Pre-Patient Collimator

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32
Q

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

A

Post-patient Collimator

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33
Q

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.

A

Rotate

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34
Q

This refers to the linear movement of the X-ray tube
and detector along the body.

A

Translate

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35
Q

A Curved patient couch is ideal for _______

A

General Radiography

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36
Q

Low Z materials for patient couch is often made of ______

A

Carbon Fiber Graphite

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37
Q

A ________ patient couch is ideal for Radiation Therapy

A

Flat

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38
Q

Receives raw data from
the detectors and
transmits it to the
processor

A

Data Acquisition System (DAS)

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38
Q

Typical weight capacity of patient couch/table ranges from ______ to _____

A

150 kg (330 lbs) to 250 kg (550 lbs)

39
Q

The core component responsible for controlling the
entire CT scanning process, as well as processing, reconstructing, and displaying the images produced by
the scanner

A

CT Scan Computer

40
Q

Manages the processing
power for reconstruction
algorithms and system
control

A

Central Processor (CPU)

41
Q

Uses mathematical
algorithms to convert raw
data into usable images.

A

Image Reconstruction Unit

42
Q

Displays images for
radiologists, with
features for image
manipulation and
analysis

A

Display Workstation

43
Q

Stores images and data
securely, often in a
PACS or cloud-based
system.

A

Storage System

44
Q

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 _________

A

Projections

45
Q

Complete the following:

1st Generation CT Scan

  • Tube and Detector Movement
  • Beam Shape
  • Detector
A
  • Tube and Detector Movement = Rotate-Translate
  • Beam Shape = Pencil Beam
  • Detector = Single Detector, Solid-State
46
Q

Complete the following:

2nd Generation CT Scan

  • Tube and Detector Movement
  • Beam Shape
  • Detector
A
  • 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
Q

Complete the following:

3rd Generation CT Scan

  • Tube and Detector Movement
  • Beam Shape
  • Detector
A
  • 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
Q

Complete the following:

4th Generation CT Scan

  • Tube and Detector Movement
  • Beam Shape
  • Detector
A
  • Tube and Detector Movement = Rotate-Stationary
  • Beam Shape = Fan-shaped X-ray Beam (Wide)
  • Detector = 600-2000 Fixed Circular Detectors, Solid-State
49
Q

Complete the following:

5th Generation CT Scan

  • Official Name
  • Tube and Detector Movement
  • Beam Shape
  • Detector
A
  • Official Name = Electron-beam Computed Tomography
  • Tube and Detector Movement = Stationary
  • Beam Shape = Fan Beam
  • Detector = 600-2000 Fixed Detectors
50
Q

Complete the following:

6th Generation CT Scan

  • Official Name
  • Tube and Detector Movement
  • Beam Shape
  • Detector
A
  • 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
Q

Complete the following:

7th Generation CT Scan

  • Official Name
  • Tube and Detector Movement
  • Beam Shape
  • Detector
A
  • Official Name = 64/128/254 Multi-Slice CT
  • Tube and Detector Movement = Rotate-Stationary
  • Beam Shape = Fan-shaped Beam (Wide)
  • Detector = Multiple Detectors
52
Q

Which CT scanner generation is prone to Ring Artifacts ?

A

3rd Generation CT Scan

53
Q

Which CT scanner generation is extremely fast and capable of imaging the beating heart ?

A

5th Generation CT Scan

54
Q

It is the most basic form of CT scanner taking one slice of the body at a time

A

Single-Slice CT Scanner

55
Q

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

A

Spiral (Helical) CT Scanner

55
Q

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

A

Multi-Slice CT Scanner

55
Q

Primarily used in dental, ENT (ear, nose, and throat), and orthopedic imaging

A

Cone-Beam CT Scanner

56
Q

Uses two different X-ray energy levels to create
images, which are then analyzed to differentiate
between materials based on their atomic composition

A

Dual-Energy CT Scanner

56
Q

PET Scan shows _______ while the CT scan provides ______

A

PET Scan = Metabolic Activity

CT Scan= Detailed Anatomical Images

57
Q

Combines PET and CT Scanning technology in a single machine

A

PET-CT Scanner

57
Q

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).

A

Portable CT Scanner

57
Q

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

A

Cardiac CT Scanner

58
Q

Controls the energy level of the X-ray beam, determining its penetration ability.

A

Kilovolt Peak (kVp)

58
Q

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

A

Interventional CT Scanner

58
Q

High kVp = ____ Contrast

59
Q

Low kVp = _____ Contrast

59
Q

Typical mAs range for CT

A

100-400 mAs

59
Q

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.

A

Milliampere-Seconds (mAs)

60
Q

TRUE OR FALSE:

Higher kVp provides better
penetration and can result in increased patient dose but
may decrease soft tissue contrast.

A

FALSE

Higher kVp provides better
penetration and can result in REDUCED patient dose but
may decrease soft tissue contrast.

61
Q

Typical range of kVp in CT

A

70 - 140 kVp

62
Q

Refers to the thickness of each individual cross- sectional image (or “slice”) obtained during the scan

A

Slice Thicknesss

63
Q

Common slice thicknesses in CT range from ______ to ______

A

0.5 mm to 5 mm

64
Q

These slices are often used for more routine imaging when fine detail is less critical

A

Thicker Slices

64
Q

Which type of slice offer higher resolution and better detail, especially for detecting small lesions, fine anatomical structures, or in 3D reconstructions

A

Thinner Slices

65
Q

The relationship between patient couch movement and
x-ray beam width

A

Pitch Ratio

66
Q

Pitch Ratio formula is:

A

Couch Movement each 360 degrees ÷ Beam Width

66
Q

TRUE OR FALSE

High Pitch means Lower Radiation Dose and Lower Image Quality

66
Q

TRUE OR FALSE:

Low Pitch means Higher Radiation Dose and Higher Image Quality

66
Q

A single square or picture element within a matrix

67
Q

The four (4) main factors contributing to image quality are:

A
  1. Spatial Resolution
  2. Contrast Resolution
  3. Noise
  4. Artifacts
67
Q

Measure of how far apart two objects must be before they can be seen as separate details in the image

A

Resolution

67
Q

Resolution is measured in ________

A

Line Pairs per Centimeter (lp/cm)

68
Q

Array of numbers arranged in a grid of rows and columns

69
Q

Pertains to the added dimension / tissue volume given to a pixel

70
Q

Describes the amount of blurring in an image

A

Spatial Resolution

70
Q

What are the five (5) scan parameters that affect spatial resolution:

A
  1. Focal Spot Size
  2. Slice Thickness
  3. Display FOV
  4. Matrix
  5. Reconstruction Algorithm
71
Q

It is the most significant geometric factor contributing to spatial resolution

A

Detector Aperture Width

71
Q

Ability to differentiate
between small differences in density within the image.

A

Contrast Resolution

72
Q

Primarily affects contrast
resolution by serving as graininess in the image

73
Q

Any distortion or error in the image that does not represent true anatomy or pathology of the patient.

74
Q

If a patient cannot or will not hold still, the scan will likely be non - diagnostic.

A

Patient Factor

75
Q

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

A

Slice Thickness

76
Q

Are usually preselected by the computer as part of the scan program, but they can be altered by the technologist.

77
Q

Scan Diameter is also called as _______

77
Q

The image that appears on the CRT depends on the ______

A

Scan Diameter

78
Q

Give the seven (7) types of artifacts in CT:

A
  1. Motion Artifacts
  2. Metal Artifacts
  3. Beam Hardening
  4. Partial Volume Artifacts
  5. Aliasing Artifacts
  6. Ring Artifacts
  7. Noise
79
Q

Noise is also known as _______

A

Quantum Mottle

COMPUTED TOMOGRAPHY (2 decks)

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