CT Scan Accessories: Quiz and Flashcards

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Questions and Answers

What is one of the software options available for CT scanners?

EEG data analysis

Bone mineral analysis (correct)

Blood pressure measurement

Blood glucose level measurement

What is the purpose of accessories in CT scanners?

To reduce the radiation dose

To increase the weight of the scanner

To reduce the cost of the scanner

To enhance the overall efficiency of the CT examination (correct)

What is the benefit of the modular design concept in CT scanners?

To simplify the upgrading of the scanner (correct)

To increase the cost of the scanner

To reduce the size of the scanner

To reduce the functionality of the scanner

What is the purpose of the rapid or dynamic scan mode in CT scanners?

To reduce the scanning time Signup and view all the answers

What is the purpose of the scanning room in a CT equipment setup?

To accommodate gurneys and emergency equipment Signup and view all the answers

What is typically housed in the computer room of a CT equipment setup?

The host computer and peripheral computing equipment Signup and view all the answers

What does extrapolation refer to in the context of CT scans?

estimation of value beyond the range of known values Signup and view all the answers

What does the pitch ratio in CT scans represent?

ratio of the distance the ct table moves to the distance the x-ray tube moves Signup and view all the answers

What happens to the volume of tissue that can be imaged in each time as pitch increases above 1:1?

it increases Signup and view all the answers

What is the effect of narrow collimation and low pitch on z-axis resolution?

it improves Signup and view all the answers

What is the relationship between spiral CT pitch and patient dose?

as spiral CT pitch increases, patient dose is reduced Signup and view all the answers

What happens to the x-ray beams during a CT scan?

they move in a circular motion around the patient Signup and view all the answers

What is the result of magnification using original image projections?

An improvement in spatial resolution Signup and view all the answers

What is the relationship between the ct number and the x-ray attenuation coefficient (μ)?

The ct number is directly related to the x-ray attenuation coefficient (μ) Signup and view all the answers

What is the purpose of quantitative ct (qct)?

To compare vertebral bone numbers with a standard phantom Signup and view all the answers

What is the result of post-processing in ct imaging?

The same information presented differently Signup and view all the answers

What is the purpose of maximum intensity projection (mip) images?

To separate superimposed vessels Signup and view all the answers

In what modality was maximum intensity projection (mip) first employed?

MRI Signup and view all the answers

What is the term for the smallest element in a digital image?

Pixel Signup and view all the answers

What is the relationship between pixel size and spatial resolution?

Smaller pixel size results in higher spatial resolution Signup and view all the answers

What is the main cause of streaking artifacts in CT images?

Inconsistency in a single measurement Signup and view all the answers

What type of artifact is caused by the physical processes involved in the acquisition of CT data?

Physics-based artifact Signup and view all the answers

What is the term for any discrepancy between the CT numbers in the image and the expected CT number?

Artifact Signup and view all the answers

What is the term for the process of collecting the exit radiation in CT scanning?

Scanning process Signup and view all the answers

What is the main cause of partial volume artifact in CT imaging?

Tissues of widely different absorption encompassed on the same CT voxel Signup and view all the answers

What is the result of tube arcing in CT imaging?

Localized artifact and temporary loss of x-ray output Signup and view all the answers

What is the cause of streak artifact in CT imaging?

Scan done with barium contrast or high osmolar contrast medium Signup and view all the answers

What is the remedy for tube arcing in CT imaging?

Tube replacement Signup and view all the answers

What is the cause of ring artifact in CT imaging?

Malfunction of a detector in a third-generation scanner Signup and view all the answers

What is the term for dose-related image noise in CT imaging?

Photon starvation or quantum mottle Signup and view all the answers

Study Notes

CT Scanner Software and Accessories

Software options for bone mineral analysis, dynamic scan, 3D image reconstruction, and more
Accessories include pediatric cradles, arm and leg supports, and others to enhance patient immobilization and examination efficiency
Modular design concept simplifies scanner upgrading

Operating Modes and Room Layout

Routine scan mode and rapid or dynamic scan mode available
Spiral/helical scan modes include overlap scan, skip scan, and tilt scan
Scanning room houses gantry and patient couch, with computer room for host computer and peripherals

CT Desirable Characteristics

High efficiency, quick response time, and high dynamic range
Stability in image reconstruction

Image Reconstruction

Scanning process produces image through x-ray beam attenuation
Exit radiation collected by detectors, reconstructed into pixels
Pixel size affects spatial resolution and detail in the image

Image Artifacts

Discrepancies between CT numbers and expected values
Appearance: streaking, shading, rings, and bands
Sources: patient, imaging process, and equipment
Types: physics-based, patient-based, and scanner-based

Pitch and Volume Imaging

Pitch is the distance the CT table moves during one x-ray tube revolution
Pitch is expressed as a ratio, affecting volume of tissue imaged in each time
Increasing pitch above 1:1 increases volume of tissue imaged, but reduces patient dose
Low pitch results in better z-axis resolution

Data Collection and Reconstruction

X-ray source and detector must be aligned and move around the patient
Many transmission measurements taken
Beam attenuated by patient, detected by scanner, and converted to digital value
Reconstruction computer processes digital values into image

Post-processing and CT Numbers

Magnification using original image projections (target zoom) improves spatial resolution
Post-processing does not add new information, just presents it differently
CT numbers are directly related to x-ray attenuation coefficient (μ) for tissue in the voxel
Hounsfield scale of Hounsfield units (HU) is the standard scale for CT numbers

Multiplanar Reconstruction and Quantitative CT

Most applied MPR algorithms result in MIP and SSD
MPR produces coronal and sagittal images from stacked transverse images
QCT compares vertebral bone numbers with a standard phantom to assay bone mineralization

Equipment and Imaging Process Artifacts

Partial volume artifact occurs when tissues of widely different absorption are encompassed on the same CT voxel
Streak artifact occurs with barium contrast or high osmolar contrast medium
Tube arcing occurs due to short-circuit within the tube
Ring artifact occurs due to detector malfunction
Staircase artifact occurs due to improper selection of slice thickness and slice increment
Quantum mottle or photon starvation occurs due to insufficient x-ray photons reaching the detector

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Description

This quiz covers the various software options and accessories available for CT scans, including bone mineral analysis, 3D image reconstruction, and patient immobilization tools. Test your knowledge of CT scan equipment and their uses. Learn about the different types of CT scans and their applications.

CT Scan Equipment and Accessories