Podcast
Questions and Answers
Conventional tomography allows for obtaining three-dimensional images of tissues.
Conventional tomography allows for obtaining three-dimensional images of tissues.
False
Computed tomography uses computerized methods to transform data into images.
Computed tomography uses computerized methods to transform data into images.
True
A slice in CT imaging refers to a two-dimensional part of the body.
A slice in CT imaging refers to a two-dimensional part of the body.
False
The term 'photon' refers to a unit of all electromagnetic waves.
The term 'photon' refers to a unit of all electromagnetic waves.
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Projections in CT refer to a single X-ray beam passing through the patient.
Projections in CT refer to a single X-ray beam passing through the patient.
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Conventional X-rays interact with tissues in a manner that allows for high accuracy in soft tissue lesion detection.
Conventional X-rays interact with tissues in a manner that allows for high accuracy in soft tissue lesion detection.
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The thickness of a CT slice is determined by the width of the X-ray beam.
The thickness of a CT slice is determined by the width of the X-ray beam.
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Computed Axial Tomography (CAT scan) aims to avoid tissue superimposition.
Computed Axial Tomography (CAT scan) aims to avoid tissue superimposition.
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Slip ring technology allows the X-ray tube to rotate continuously in both directions around the patient.
Slip ring technology allows the X-ray tube to rotate continuously in both directions around the patient.
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CT scans create images by compressing three-dimensional structures onto a two-dimensional recording system.
CT scans create images by compressing three-dimensional structures onto a two-dimensional recording system.
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The sensitivity of CT is at least ten times higher than conventional film-screen recording systems due to reduced scatter.
The sensitivity of CT is at least ten times higher than conventional film-screen recording systems due to reduced scatter.
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The basic function of a CT scanner is to measure X-ray attenuation through a single point in the body.
The basic function of a CT scanner is to measure X-ray attenuation through a single point in the body.
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CT images are reconstructed using data analyzed by a computer from measurements taken at various angles.
CT images are reconstructed using data analyzed by a computer from measurements taken at various angles.
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Computers can reconstruct cross-sectional images of the body using an infinite number of projections from one angle.
Computers can reconstruct cross-sectional images of the body using an infinite number of projections from one angle.
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The first CT head scanner was developed in 1969.
The first CT head scanner was developed in 1969.
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Axial sections in CT are important for increasing image quality and avoiding superimposition.
Axial sections in CT are important for increasing image quality and avoiding superimposition.
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Computed tomography utilizes ultrasound technology to generate images of the body.
Computed tomography utilizes ultrasound technology to generate images of the body.
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The Nobel Prize in 1979 was awarded to Cormack and Hounsfield for their contributions to the development of CT technology.
The Nobel Prize in 1979 was awarded to Cormack and Hounsfield for their contributions to the development of CT technology.
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Typically, during one complete 360° rotation, about 500 projections are measured for CT imaging.
Typically, during one complete 360° rotation, about 500 projections are measured for CT imaging.
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CT scans can be used to detect conditions like brain tumors and cardiac issues.
CT scans can be used to detect conditions like brain tumors and cardiac issues.
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The first clinically used CT scan took place in 1975.
The first clinically used CT scan took place in 1975.
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Study Notes
CT Introduction & Historical Outline
- Tomography = layer, section, or slice
- Conventional Tomography: Special imaging for specific tissue layers; superimposes other tissues
- Disadvantages of conventional X-rays:
- Travels in straight lines, resulting in absorbed/scattered X-rays
- Two-dimensional images; tissue overlying and superimposition causes blurring and reduced visibility
- Inability to differentiate tissue with similar densities
- Less accurate detection of soft tissue lesions
- X-ray photons interact with specific parts
- Computed Tomography (CT): Tomo meaning layer, slice, section or cut; Computed using computerized methods and processors to transform data into images of axial or transverse slices.
Terminology of Computed Tomography
- Tomography: Meaning layer, section, slice or cut
- Computed Tomography (CT): Computer-based imaging modality utilizing X-ray tissue interaction to produce multiple axial (transverse) slices. Avoids the superimposition of tissues typical of conventional X-ray imaging.
Slice Definition
- Slice: Cross-sectional part of body scanned to produce a CT image. Has three dimensions (length, width and depth); thickness determined by the X-ray beam width.
CT Axial Cuts
- Conventional tomography scans have low contrast resolution and long scanning times; produces images in layers
- Axial scans achieved by rotating X-ray tube 360 degrees with patient motion simultaneously to produce a cross-section of body
- X-ray travels in straight lines; this axial view avoids superimposition.
Specific Terminology
- Photon: Unit of electromagnetic wave
- Ray: Imaginary line between the tube and detector
- Beam: Group of rays with a different angle
CT Principles
- CT reconstructs cross-sectional images from multiple X-ray projections
- The body's internal structure can be reconstructed from multiple X-ray projections
- The transmitted radiation measured from sensitive radiation detectors around the patient in a ring.
- A computer reconstructs a digital image from these measurements
- X-ray beam rotates around the patient creating different projections
- CT scans are more sensitive (10 times higher) to subtle changes in X-ray attenuation and it eliminates scatter.
- Measurement of X-ray attenuation through different sections of body results in multiple scans, a computer software reconstruct the digital image of the cross sectional body part from these measurements
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Description
This quiz explores the fundamentals of Computed Tomography (CT) and its historical development. It covers the advantages of CT over conventional X-rays, including imaging techniques and terminology used in the field. Test your knowledge on how CT produces images and its significance in medical diagnostics.
