MCQ Tomography Equipment
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Questions and Answers

What are the essential characteristics of scintillation detectors used in CT Scanners?

  • short primary decay time (up to tens of us) (correct)
  • low afterglow (correct)
  • radiation damage resistance (correct)
  • All of the above (correct)
  • high light output (correct)

Gas-ionization detectors, based on the principle of ionization, were first introduced in which generation of CT scanners?

  • First-generation scanners
  • Fourth-generation scanners
  • Second-generation scanners
  • Unique-generation scanners
  • Third-generation scanners (correct)

What type of detectors are primarily used in MSCT scanners?

  • Solid-state detector arrays (correct)
  • Gas-ionization detectors
  • Xenon detectors
  • Scintillation detectors
  • All of the above

How does the attenuation coefficient of a tissue change with its thickness and x-ray photon energy?

<p>Not constant (A), May be altered by the tissue thickness (B), Depends on the energy of the x-ray photon (KeV) (C), The higher the tissue density, the higher its u value (D), All of the above (E)</p> Signup and view all the answers

What is the process called where projected datasets are 'back-projected' to form corresponding images in CT?

<p>BP1, BP2, BP3 and BP4 (B)</p> Signup and view all the answers

What is the key process involved in image reconstruction in CT?

<p>Summing back-projected images to form an image of the object (D)</p> Signup and view all the answers

What is the main advantage of back-projection reconstruction in CT?

<p>Short time for complete reconstruction (≤30-40 slices per second) (E)</p> Signup and view all the answers

What is the primary advantage of iterative image reconstruction algorithms in CT?

<p>To reduce image noise and minimize the higher radiation dose inherent in the filtered back-projection algorithm (B)</p> Signup and view all the answers

What are the two key differences between single-slice CT (SSCT) and multi-slice CT (MSCT)?

<p>The first involves the relationship between slice thickness and x-ray beam width. The second relates to beam configuration effects. (E)</p> Signup and view all the answers

What are the primary advantages of MS/MD-CT over conventional CT?

<p>Its speed can be used for fast imaging of large volumes of tissue with wide sections (B)</p> Signup and view all the answers

What materials are typically used in X-rays films?

<p>Silver bromide (A)</p> Signup and view all the answers

Which unique operating modes are related to dual-source CT (DSCT)?

<p>Dual Source Single Energy (DSSE) (B), Dual Source mode (C), Both a, b and c (D), Dual Source Dual Energy (DSDE) (A)</p> Signup and view all the answers

What is considered an acute or deterministic effect of radiation exposure?

<p>High level of radiation over short period of time (A)</p> Signup and view all the answers

What factors generally limit the maximum field of view achievable in a radiographic system?

<p>Anode angle (E)</p> Signup and view all the answers

Which factor has the greatest impact on limiting the maximum mA used during a radiographic exposure?

<p>Focal spot size (A)</p> Signup and view all the answers

How can you increase the primary x-ray beam penetration (percent) through a patient?

<p>KV (A)</p> Signup and view all the answers

Why are relatively low KV values often utilized in X-ray procedures?

<p>Increasing contrast sensitivity (B)</p> Signup and view all the answers

What are the general consequences of decreasing the KV in X-ray imaging?

<p>Increase patient exposure (C)</p> Signup and view all the answers

Changing from a 5:1 to a 10:1 grid ratio in X-ray imaging will generally result in:

<p>Increase Image contrast (B)</p> Signup and view all the answers

Which of the following factors would NOT generally decrease the visibility and contrast of a 1 cm soft tissue mass in the body?

<p>Focal spot size (A)</p> Signup and view all the answers

What is the primary difference between a 'medium' and a 'high' speed intensifying screen, assuming the same phosphor material?

<p>Visibility of anatomical detail (B)</p> Signup and view all the answers

What is the impact of intensifying screen thickness on image quality?

<p>Image contrast (A)</p> Signup and view all the answers

Which of the following steps is NOT considered part of the CT image reconstruction process?

<p>Image display (A), Storage (B), A, B, and C (D), All of the above (E), Communication (C)</p> Signup and view all the answers

What is the specific number of shades of gray used to represent a CT image called?

<p>The window width (WW) (B)</p> Signup and view all the answers

What is the center or midpoint of the CT number range that defines a CT image's gray scale called?

<p>Window level (WL) (A)</p> Signup and view all the answers

What is the television monitor that displays the grayscale image in CT called?

<p>Cathode ray tube [CRT] (A)</p> Signup and view all the answers

What does CT stand for?

<p>Computed Tomography Scan (B)</p> Signup and view all the answers

What is computed tomography also known as?

<p>Transmission tomography (B)</p> Signup and view all the answers

Compared to conventional radiography, what are the key advantages of CT?

<p>Better spatial resolution and improved contrast resolution (A)</p> Signup and view all the answers

What are some of the primary applications of industrial computed tomography scanning?

<p>flaw detection (A), reverse engineering (B), failure investigation (C)</p> Signup and view all the answers

What is NOT typically a primary application of industrial CT scanning?

<p>None of the above (E)</p> Signup and view all the answers

What are some of the features that enable industrial CT scanning to provide measurements even of hidden parts?

<p>Software programs (A)</p> Signup and view all the answers

Flashcards

Scintillation Detectors

A type of detector used in CT scanners that converts X-ray energy into light, which is then converted into electrical energy by a photodetector.

Gas-Ionization detectors

A type of detector used in older CT scanners that are based on the principle of ionization. They were introduced in the first generation of CT scanners.

Solid-state detectors

A type of detector used in modern CT scanners, especially MSCT scanners, that rely on the interaction of X-rays with a solid material.

Attenuation Coefficient (μ)

The measure of how much a substance attenuates (weakens) an X-ray beam. It is dependent on the energy of the X-ray photon and the density of the tissue.

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Back Projection (BP)

A method of reconstructing images in CT by combining multiple projections of an object.

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Filtered Back Projection (FBP)

A type of reconstruction algorithm used in CT that involves summing multiple back-projected images to create a final image. It is simple but can lead to artifacts - blurring or streaks.

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Iterative Reconstruction

A type of reconstruction algorithm that uses iterative methods to reduce noise and artifacts in the CT image. It can provide better quality images with lower radiation dose, but requires more processing time.

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Multi-Slice CT (MSCT)

A type of CT scanner that uses multiple X-ray sources and detectors to acquire multiple slices of data simultaneously. It's much faster than single-slice CT (SSCT), allowing for faster scans and capturing larger volumes of tissue.

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Single-Slice CT (SSCT)

A type of CT scanner that only acquires data for a single slice at a time. It's slower than MSCT, but it's more affordable.

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Silver Bromide

A type of x-ray film material that is sensitive to X-rays and produces an image when exposed.

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Fan beam

A type of x-ray beam arrangement used in some CT scanners. The beam is shaped like a fan beam with a wider coverage, allowing for faster scan times and larger volumes to be captured.

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Cone beam

A type of x-ray beam arrangement used in some CT scanners. The beam is shaped like a cone beam, allowing for even faster scan times and larger volumes to be captured.

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Dual Source CT (DSCT)

A type of CT scan that uses two x-ray sources and detectors to acquire data at two different energies, providing better tissue differentiation and reducing artifacts.

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Acute Radiation Effects

The effect of high-dose radiation exposure over a short period of time. It can cause immediate symptoms like burns or radiation sickness.

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Chronic Radiation Effects

The effect of low-dose radiation exposure over a long period of time. It can lead to increased risk of cancer over the lifetime.

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Field Of View (FOV)

The maximum size of an object that can be clearly visualized with a specific radiographic system, often limited by the size of the x-ray tube anode.

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Focal Spot

The point where the x-ray beam originates from within the x-ray tube. It's a key factor in image sharpness.

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Anode Angle

The angle of the anode in the x-ray tube. It affects the focal spot size and X-ray beam distribution.

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Film-Focus Distance

The distance from the x-ray tube to the detector. It affects the sharpness and magnification of the image.

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Milliamperage (mA)

The amount of electrical current flowing through the x-ray tube. It directly affects the intensity of the x-ray beam.

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Kilovoltage (kV)

The voltage applied across the x-ray tube. It determines the energy of the x-ray beam.

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Milliampere-seconds (mAs)

The product of mA and exposure time (seconds), representing the total amount of x-ray energy delivered to the patient during an exposure.

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Grid

A device used in x-ray imaging to absorb scattered radiation and improve image contrast. It consists of thin lead strips interspersed with radiolucent material.

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Photostimulable Phosphor (PSP) Plate

A type of imaging plate used in digital radiography. It contains a photostimulable phosphor material that stores X-ray energy and releases it as light when stimulated.

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Image Reconstruction

The process in CT where acquired data is used to create images. It involves combining multiple projections of the object to reconstruct a 3D representation of the object.

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Filtering

A type of image enhancement technique in CT that uses specific filters to reduce noise and emphasize edges in the images.

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Window Width (WW)

The range of CT numbers that are displayed in the final CT image. It affects the contrast of the image.

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Window Level (WL)

The center point of the CT number range that is being displayed. It affects the overall brightness of the image.

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Cathode Ray Tube (CRT)

The type of monitor used in CT systems to display images. It uses a cathode ray tube to produce images.

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Study Notes

MCQ Tomography Equipment

  • X-ray energy is converted into light, then light into mechanical or electrical or magnetic energy by a photodetector.
  • CT scintillation detectors require high light output, short primary decay time, low afterglow, and radiation damage resistance.
  • Gas-ionization detectors, based on ionization, were introduced in first-generation scanners.
  • Multislice CT scanners (MSCT) use solid-state detector arrays.
  • Tissue attenuation coefficient is not constant, and depends on x-ray photon energy and tissue thickness, with higher tissue density corresponding to higher u-value.
  • Back-projected datasets form images of the object.
  • The reconstruction process uses back-projected images of an object to form an image of the object.
  • Back-projection is explained using matrices such as 2x2, 3x3 ,1x1, X4 matrix
  • Advantages of Back Projection (BP) include short reconstruction times (e.g., ≤30–40 slices per second).
  • Iterative image reconstruction algorithms reduce image noise and minimize radiation dose compared to filtered back-projection (FBP)

X-Ray Tomography

  • Modern multislice/multidetector CT (MS/MDCT) scanners have faster imaging of large volumes of tissue with wide sections or wide areas.
  • Photosensitive materials used in X-ray films include silver bromide or zinc sulfide
  • Dual-source CT (DSCT) has different operating modes like Dual Source Single Energy (DSSE) and or Dual Source Dual Energy (DSDE) using different kVp settings (e.g., 20 kVp and 140 kV) for different energies.
  • Acute or deterministic effects of radiation exposure are high levels of radiation over short periods.
  • Radiographic system limits are related to focal spot size, anode size, anode angle, focal length and cathode temperature.

CT Image Quality

  • Increasing x-ray beam penetration (percent) is achieved by increasing kV.
  • Low kV values are used to increase contrast sensitivity, reduce patient exposure, or decrease area contrast.
  • Changing kV from 90 to 70 generally decreases calcium-soft tissue contrast and increases patient exposure.
  • Changing from a 5:1 ratio to a 10:1 ratio grid will decrease patient exposure and increase image contrast resulting in reduction in KV or MAS values.
  • Increasing focal spot size, field of view (FOV), and decreasing object-receptor distance will reduce tissue mass visibility and contrast
  • Radiographic intensifying screen speed changes such as high-speed screen will reduce quantum noise and exposure latitude , with less visibility of anatomical detail and contrast reduction
  • CT image display involves image storage, communication, and display, with the number of shades of gray called window space and window width (WW).
  • The center or midpoint of the CT# range is called window level.
  • The display on a television monitor is called a cathode ray tube (CRT/CRm).

Industrial CT

  • Industrial CT scans are used for assembly analysis, material analysis, void, cracks, and defect detection.
  • Industrial CT scanning employs software programs, flat-panel X-ray detectors, or cone beam X-ray sources.

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Ibn Khaldun University College MCQ Tomography Equipment 2023-2024 PDF

Description

Test your knowledge on the various tomography equipment and techniques used in medical imaging. This quiz covers topics such as X-ray energy conversion, detector types, and image reconstruction processes. Perfect for students and professionals in radiology and medical imaging.

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