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Questions and Answers
What are the essential characteristics of scintillation detectors used in CT Scanners?
What are the essential characteristics of scintillation detectors used in CT Scanners?
Gas-ionization detectors, based on the principle of ionization, were first introduced in which generation of CT scanners?
Gas-ionization detectors, based on the principle of ionization, were first introduced in which generation of CT scanners?
What type of detectors are primarily used in MSCT scanners?
What type of detectors are primarily used in MSCT scanners?
How does the attenuation coefficient of a tissue change with its thickness and x-ray photon energy?
How does the attenuation coefficient of a tissue change with its thickness and x-ray photon energy?
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What is the process called where projected datasets are 'back-projected' to form corresponding images in CT?
What is the process called where projected datasets are 'back-projected' to form corresponding images in CT?
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What is the key process involved in image reconstruction in CT?
What is the key process involved in image reconstruction in CT?
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What is the main advantage of back-projection reconstruction in CT?
What is the main advantage of back-projection reconstruction in CT?
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What is the primary advantage of iterative image reconstruction algorithms in CT?
What is the primary advantage of iterative image reconstruction algorithms in CT?
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What are the two key differences between single-slice CT (SSCT) and multi-slice CT (MSCT)?
What are the two key differences between single-slice CT (SSCT) and multi-slice CT (MSCT)?
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What are the primary advantages of MS/MD-CT over conventional CT?
What are the primary advantages of MS/MD-CT over conventional CT?
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What materials are typically used in X-rays films?
What materials are typically used in X-rays films?
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Which unique operating modes are related to dual-source CT (DSCT)?
Which unique operating modes are related to dual-source CT (DSCT)?
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What is considered an acute or deterministic effect of radiation exposure?
What is considered an acute or deterministic effect of radiation exposure?
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What factors generally limit the maximum field of view achievable in a radiographic system?
What factors generally limit the maximum field of view achievable in a radiographic system?
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Which factor has the greatest impact on limiting the maximum mA used during a radiographic exposure?
Which factor has the greatest impact on limiting the maximum mA used during a radiographic exposure?
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How can you increase the primary x-ray beam penetration (percent) through a patient?
How can you increase the primary x-ray beam penetration (percent) through a patient?
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Why are relatively low KV values often utilized in X-ray procedures?
Why are relatively low KV values often utilized in X-ray procedures?
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What are the general consequences of decreasing the KV in X-ray imaging?
What are the general consequences of decreasing the KV in X-ray imaging?
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Changing from a 5:1 to a 10:1 grid ratio in X-ray imaging will generally result in:
Changing from a 5:1 to a 10:1 grid ratio in X-ray imaging will generally result in:
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Which of the following factors would NOT generally decrease the visibility and contrast of a 1 cm soft tissue mass in the body?
Which of the following factors would NOT generally decrease the visibility and contrast of a 1 cm soft tissue mass in the body?
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What is the primary difference between a 'medium' and a 'high' speed intensifying screen, assuming the same phosphor material?
What is the primary difference between a 'medium' and a 'high' speed intensifying screen, assuming the same phosphor material?
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What is the impact of intensifying screen thickness on image quality?
What is the impact of intensifying screen thickness on image quality?
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Which of the following steps is NOT considered part of the CT image reconstruction process?
Which of the following steps is NOT considered part of the CT image reconstruction process?
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What is the specific number of shades of gray used to represent a CT image called?
What is the specific number of shades of gray used to represent a CT image called?
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What is the center or midpoint of the CT number range that defines a CT image's gray scale called?
What is the center or midpoint of the CT number range that defines a CT image's gray scale called?
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What is the television monitor that displays the grayscale image in CT called?
What is the television monitor that displays the grayscale image in CT called?
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What does CT stand for?
What does CT stand for?
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What is computed tomography also known as?
What is computed tomography also known as?
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Compared to conventional radiography, what are the key advantages of CT?
Compared to conventional radiography, what are the key advantages of CT?
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What are some of the primary applications of industrial computed tomography scanning?
What are some of the primary applications of industrial computed tomography scanning?
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What is NOT typically a primary application of industrial CT scanning?
What is NOT typically a primary application of industrial CT scanning?
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What are some of the features that enable industrial CT scanning to provide measurements even of hidden parts?
What are some of the features that enable industrial CT scanning to provide measurements even of hidden parts?
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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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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.
