Lesson 3 (PRELIMS) Flashcards
(104 cards)
1
Q
Enumerate CT Generations
A
- Scanning pencil beam
- Scanning fan beam
- Full fan - beam with rotating detector
- Full fan - beam with stationary detector ring
- Electron - beam CT (EBCT)
- Spiral CT
- Multislice CT
2
Q
Types of scanner
A
- Single-slice CT scanner
- Multi-slice CT scanner
- Spiral (helical) CT scanner
- Cone-beam CT scanner
- Cardiac CT scanner
- Dual-energy CT scanner
- PET-CT scanner
- Interventional CT scanner
- Portable CT scanner
2
Q
Types of Scanner: Description: The most basic form of CT scanner.
A
Single-slice CT scanner
3
Q
Types of Scanner: Description: Takes one slice (cross-sectional image) of the body at a time.
A
Single-slice CT scanner
4
Q
Types of Scanner: Description: The X-ray tube and detectors rotate around the body to capture a series of 2D images.
A
Single-slice CT scanner
4
Q
Types of Scanner: Common Uses: Basic diagnostics, such as detecting fractures or simple tumors.
A
Single-slice CT scanner
5
Q
Types of Scanner: Common Uses: Less commonly used today due to advancements in multi-slice technology.
A
Single-slice CT scanner
6
Q
Types of Scanner: Common Uses: Basic, Older Technology and for General Use.
A
Single-slice CT scanner
6
Q
Types of Scanner: Description: 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
7
Q
Types of Scanner: Description: Faster than single-slice scanners and provides higher resolution images.
A
Multi-slice CT scanner
8
Q
Types of Scanner: Description: Can produce 3D images by stacking the multiple slices.
A
Multi-slice CT scanner
9
Q
Types of Scanner: Common Uses: More detailed diagnostic imaging.
A
Multi-slice CT scanner
10
Q
Types of Scanner: Common Uses: Used in various fields, including oncology, cardiology, and trauma care.
A
Multi-slice CT scanner
11
Q
Types of Scanner: Common Uses: Faster and better for imaging complex areas such as the heart or blood Vessels.
A
Multi-slice CT scanner
12
Q
Types of Scanner: Common Uses: Advanced, faster, and better resolution for complex imaging (e.g., organs, blood vessels).
A
Multi-slice CT scanner
13
Q
Types of Scanner: Description: The X-ray tube continuously rotates around the patient while they move through the scanner in a spiral motion.
A
Spiral (helical) CT scanner
13
Q
Types of Scanner: Description: Produces continuous images without interruption and allows for a more efficient scan.
A
Spiral (helical) CT scanner
14
Q
Types of Scanner: Common Uses: Highly beneficial in emergency situations.
A
Spiral (helical) CT scanner
14
Q
Types of Scanner: Common Uses: Frequently used for chest, abdominal, and brain imaging.
A
Spiral (helical) CT scanner
14
Q
Types of Scanner: Common Uses: Used to detect conditions like pulmonary embolisms, strokes, and certain types of cancers.
A
Spiral (helical) CT scanner
14
Q
Types of Scanner: Common Uses: Quick imaging of the chest, abdomen, and pelvis; diagnosing pulmonary embolism, appendicitis, and cancer staging.
A
Spiral (helical) CT scanner
15
Q
Types of Scanner: Description: A specialized CT scanner that focuses on imaging the heart and blood vessels.
A
Cardiac CT scanner
16
Q
Types of Scanner: Description: Often used to assess coronary artery disease, heart function, and abnormalities in the heart’s structures. Common Uses:
A
Cardiac CT scanner
16
Q
Types of Scanner: Common Uses: Assessing coronary artery disease (such as blockages or narrowing of arteries).
A
Cardiac CT scanner
17
Types of Scanner: Common Uses: Planning heart surgery or evaluating heart function.
Cardiac CT scanner
18
Types of Scanner: Common Uses: Used to visualize blood vessels for conditions like aneurysms.
Cardiac CT scanner
19
Types of Scanner: Common Uses: Designed for imaging the heart and coronary arteries with high-speed scanning for detailed heart and blood vessel analysis.
Cardiac CT scanner
20
Types of Scanner: Description: Primarily used in dental, ENT (ear, nose, and throat), and orthopedic imaging.
Cone - Beam CT Scanner
21
Types of Scanner: Description: The scanner uses a cone-shaped X-ray beam to capture detailed 3D images of the body, particularly the head and neck region.
Cone - Beam CT Scanner
21
Types of Scanner: Common Uses: Used for sinus, ear, and nasal cavity scans.
Cone - Beam CT Scanner
22
Types of Scanner: Common Uses: Dental and orthodontic imaging, such as evaluating the jaw, teeth, and bones of the face.
Cone - Beam CT Scanner
22
Types of Scanner: Common Uses: Less radiation exposure compared to traditional CT in some cases.
Cone - Beam CT Scanner
23
Types of Scanner: Common Uses: Dental and maxillofacial imaging, planning dental implants, and evaluating head and neck conditions.
Cone - Beam CT Scanner
23
Types of Scanner: Description: Uses two different X-ray energy levels to create images, which are then analyzed to differentiate between materials based on their atomic composition.
Dual - Energry CT Scanner
24
Types of Scanner: Description: This technology allows for more precise imaging of soft tissues, blood vessels, and organs, and can be used to distinguish between different types of stones (like kidney stones).
Dual - Energry CT Scanner
25
Types of Scanner: Common Uses: Used for advanced imaging of tissues, particularly in oncology to differentiate between tumors and healthy tissue.
Dual - Energry CT Scanner
26
Types of Scanner: Common Uses: Helpful for identifying conditions like gout or kidney stones, as it can distinguish different types of tissue or stones based on their material.
Dual - Energry CT Scanner
27
Types of Scanner: Common Uses: Differentiating tissue types, detecting cancer, assessing kidney stones, gout, and vascular conditions.
Dual - Energry CT Scanner
27
Types of Scanner: Description: Combines Positron Emission Tomography (PET) and CT scanning technology in a single machine.
PET - CT Scanner
28
Types of Scanner: Description: The PET scan shows metabolic activity (how tissues and organs are functioning), while the CT scan provides detailed anatomical images.
PET - CT Scanner
28
Types of Scanner: Description: Particularly useful for detecting cancers, assessing heart function, and evaluating brain disorders.
PET - CT Scanner
29
Types of Scanner: Common Uses: Mostly used in oncology to locate and evaluate cancer cells.
PET - CT Scanner
30
Types of Scanner: Common Uses: Used in evaluating heart disease and brain disorders (like Alzheimer's).
PET - CT Scanner
31
Types of Scanner: Common Uses: Cancer detection and monitoring, evaluating brain conditions (like Alzheimer's), cardiac assessments, and tracking cancer treatment effectiveness.
PET - CT Scanner
32
Types of Scanner: Description: Used in a procedure where CT scans guide the doctor during surgery or a minimally invasive procedure.
Interventional CT Scanner
33
Types of Scanner: Description: Provides real-time imaging to help doctors make precise decisions during interventions, such as biopsies or the insertion of stents.
Interventional CT Scanner
34
Types of Scanner: Common Uses: Used during procedures like biopsies, drain placements, or the removal of tumors.
Interventional CT Scanner
35
Types of Scanner: Common Uses: This are vital in emergency care, offering quick, on-site diagnostic capabilities that improve patient outcomes by enabling timely decision- making and treatment.
Portable CT Scanner
36
Types of Scanner: Common Uses: Common in emergency settings for trauma care.
Interventional CT Scanner
37
Types of Scanner: Common Uses: Provides high-precision imaging for real-time guidance. Minimizes the need for open surgery by enabling minimally invasive procedures.
Interventional CT Scanner
38
Types of Scanner: Description: 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
39
Types of Scanner: Description: Less powerful than traditional CT scanners but still offers useful diagnostic capabilities.
Portable CT Scanner
39
Types of Scanner: Common Uses: Used for critically ill patients who cannot be moved easily, providing faster imaging in emergency or critical care settings.
Portable CT Scanner
40
Types of Scanner: Common Uses: Typically used in situations where transport to a full CT room is not feasible.
Portable CT Scanner
41
Enumerate scan parameters
1. kVp (Kilovolt Peak)
2. mAs (Milliampere Seconds)
3. Slice Thickness
4. Pitch Ratio
41
Scan Parameters: _____ kVp _____ the ability of the X-rays to penetrate dense structures (e.g.,bones). _____ contrast in soft tissues.
kVp (Kilovolt Peak)
Higher
Improves
Reduces
42
Scan Parameters: Controls the energy level of the X-ray beam, determining its penetration ability.
kVp (Kilovolt Peak)
43
Scan Parameters: _____ kVp _____ contrast for soft tissue imaging. May be useful for imaging the chest or abdomen, where distinguishing soft tissues is important.
kVp (Kilovolt Peak)
Lower
Increases
43
Scan Parameters: Typical Range: ___ to ___ kVp.
kVp (Kilovolt Peak)
70–140
44
Scan Parameters: Effect on Image: _____ kVp provides better penetration and can result in _____ patient dose but may _____ soft tissue contrast.
kVp (Kilovolt Peak)
Higher
Reduced
Decrease
45
Scan Parameters: The product of the X-ray tube current and the exposure time. It determines the total radiation dose delivered to the patient and affects image quality.
mAs (Milliampere Seconds)
46
Scan Parameters: _____ mAs _____ noise and _____ image quality by _____ signal intensity _____radiation dose.
mAs (Milliampere Seconds)
Higher
Reduces
Increases
Improving
Increases
47
Scan Parameters: ______ mAs results in _____ noise and grainier images _____ radiation dose but may compromise image quality, particularly in _____ patients or in detailed imaging.
mAs (Milliampere Seconds)
Lower
Higher
Reduces
Large
48
Scan Parameters: Typical Range: ___to___ mAs, depending on the body part and size.
mAs (Milliampere Seconds)
100–400
49
Scan Parameters: Effect on Image: _____ mAs improves image clarity and _____ noise, but _____radiation dose.
mAs (Milliampere Seconds)
Higher
Reduces
Increases
50
Scan Parameters: Refers to the thickness of each individual cross-sectional image (or "slice") obtained during the scan. Common range from ___ to ___.
___ is often used for higher resolution imaging, particularly for detailed views like in neurology or vascular imaging. ___ slices may be used in routine chest or abdominal scans, where a lower resolution might suffice.
Slice Thickness
0.5 mm to 5 mm
1 mm
5 mm
51
Scan Parameters: _____ Slices are often used for more routine imaging when fine detail is less critical, such as general surveys of large areas of the body. (e.g., ___ to ___). They may help _____ the overall radiation exposure.
Slice Thickness
Thicker
3 mm to 5 mm
Reduce
51
Scan Parameters: _____ Slices offer higher resolution and better detail, especially useful for detecting small lesions, fine anatomical structures, or in 3D reconstructions (e.g., ___ to ___) .However, they _____ the radiation dose and the amount of data to be processed, which might be a consideration in some cases.
Slice Thickness
Thinner
0.5 mm to 1 mm
Increase
52
Scan Parameters: The relationship between patient couch movement and x-ray beam width.
Pitch Ratio
53
Scan Parameters: Pitch Ratio Formula
PITCH = Couch movement each 360 deg. ÷ Beam width High Pitch (Fast Table Movement)
53
Scan Parameters: _____ Pitch (Slow Table Movement)
- _____ scan time:
- _____ radiation dose
- _____ image quality
- Used for: Detailed imaging of small or critical areas, such as the brain, coronary arteries, or areas needing high precision.
Pitch
Low
Longer
Higher
Higher
54
Scan Parameters: _____ scan time:
- _____ radiation dose
- _____ image quality
- Used for: Faster imaging of less critical areas, where high image resolution is less important (e.g., routine screenings or large organs like the abdomen).
Pitch
Faster
Lower
Lower
55
Scan Parameters: Beam width has some overlap at each view angle from rotation to rotation
Pitch < 1
55
Image Quality: For two objects to be seen as separate the detectors must be able to identify a gap between them.
Resolution
55
In CT the technologist has access to numerous scan parameters that can have a dramatic effect on image quality. The four main factors contributing to image quality are _____, _____, _____ and _____
Image Quality: Spatial resolution, contrast resolution, noise, and artifacts.
56
Scan Parameters: o overlap of beam width at each view angle and no view angles not covered at certain table positions
Pitch = 1
57
Scan Parameters: Some view angles are not covered by the beam width at certain table positions
Pitch > 1
57
Image Quality: _____ is the measure of how far apart two objects must be before they can be seen as separate details in the image.
Resolution
58
Image Quality: Resolution is measured in _____ i.e. the number of line pairs that can be imaged as separate structures within one centimeter.
Line pairs per centimeter (lp/cm)
59
Image Quality: _____ detectors identify the gap between the objects and so display them as separate
Smaller
60
Image Quality: _____ detectors cannot identify a gap between the two objects and so they are seen as one _____ object
Large
61
Image Quality: _____ resolution, increase image quality
Increase
62
Technical aspects:
A volume element
- The tissue volume
Voxel
62
The _____ is an array of numbers arranged in a grid of rows and columns called a _____. A single square,or picture element, within the matrix is called a _____. The slice thickness gives the pixel an added dimension called the volume element, or _____. Each _____ in the image corresponds to the volume of tissue in the body section being imaged. The _____ volume is a product of the pixel area and slice thickness
Digital image
Matrix
Pixel
Voxel
Pixel
Voxel
63
Technical aspects:
A picture element
- Each cell of information
- Two-dimensional
Pixel
64
Technical aspects:
Total number of pixel displayed (DRT).
-Rows and columns of pixels displayed on a digital
image
Matrix
65
Image Quality: Describes the amount of blurring in an image.
Spatial Resolution
66
Image Quality: The scan parameters that affect spatial resolution include _____, _____, _____, _____ and _____. The _____ is the most significant geometric factor that contributes to spatial resolution.
Focal spot size, slice thickness, display FOV, matrix, and reconstruction algorithm
Detector aperture width
67
Image Quality: The ability to differentiate between small differences in density within the image. Currently, tissues with density differences of less than _____% can be distinguished with CT.
Contrast Resolution
0.5%
68
Image Quality: Image graininess from quantum mottle and statistical fluctuation in the information detected.
Noise
69
Image Quality: The scan parameters that affect contrast resolution are _____, _____, _____ and _____. The _____ and _____ also have a direct effect on contrast resolution.
Slice thickness, reconstruction algorithm, image display, and x-ray beam energy
Size of the patient and the detector sensitivity
69
Image Quality: Standard normal noise values are ___ to ___% of the image. Ruled out by _____ test
3-5%
Water phantom
69
Image Quality: As noise increases, contrast resolution _____.
Decreases
70
Image Quality: - Noise in a CT image primarily affects _____.
Contrast resolution
71
Image Quality: Enumerate artifacts
● Motion Artifacts
● Metal Artifacts
● Beam Hardening
● Partial Volume Artifacts
● Aliasing Artifacts
● Ring Artifacts
● Noise
71
Image Quality: Among the scan parameters that influence noise are _____, _____, _____ and _____. _____ and _____ also contribute to the noise of an image.
Matrix size, slice thickness, x-ray beam energy, and reconstruction algorithm
Scattered radiation and patient size
71
Image Quality: _____ gives an image a grainy quality or a mottled appearance.
Noise
71
Image Quality: Refers to any distortion or error in the image that doesn't represent the true anatomy or pathology of the patient.
Artifact
71
Image Quality: Artifacts can arise from various factors, often related to the _____, _____, or the way data is _____.
Equipment, patient motion
Processed
72
Image quality factors under technologist control include _____, _____, _____ and _____.
Slice thickness, scan time, scan diameter, and patient factors
73
_____ If a patient cannot or will not hold still, the scan will likely be _____. _____ also can have an effect on image quality. _____ patients attenuate more radiation than _____ patients; this can _____ image noise, detracting from overall image quality. An _____ in milliampere-seconds (mAs) is usually required to compensate for _____ body size.
Patient Factor
Non - diagnostic
Body size
Large
Small
Increase
increase
Large
73
_____is usually dictated by image protocol. As in tomography, the _____ the slice thickness, the better the image recorded detail. _____-section CT scans, often referred to as _____, are used to better demonstrate structures.
Slice thickness
Thinner
Thin
High resolution scans
74
_____ are usually preselected by the computer as part of the scan program, but they can be altered by the technologist. When selecting a scan time, the technologist must take into account possible patient motion such as inadvertent _____, ______ or _____.
Scan times
Body movements, breathing, or peristalsis
74
The image that appears on the CRT depends on the _____ also called _____. The anatomy displayed is often referred to as the _____.
Scan Diameter
Scan FOV
Display FOV
