Limitations of Conventional Radiology

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Limitations of Conventional Radiology

• Superposition problem
• Solution conventional axial tomography
• Better, but still have some superposition
  problems and it is difficult to determine
  anatomical boundaries.
• 5-10 difference in density still not detectable

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Computed Tomography

• Combines power of numerical computation and
  mathematical theory withy multi-angular scanning.
• Developed in early 1970s
• Nobel Prize 1979 in Physiology and Medicine
  awarded to Allan Macleod Cormack and Godfrey
  Newbold Hounsfield
• First clinical scanner called the EMI Brain
  Scanner in Atkinson Morleys Hospital in
  Wimbledon, England

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Computed Tomography
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X-ray Computed Tomography

• Collimate beam to reduce scattering
• Trans-axial scan eliminates superposition
• Record transmissions every 0.5 to 10
• 1-2 seconds for single slice
• Density differences of just 0.5 are detectable

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X-ray Computed Tomography
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Spiral CT

• Increases volume of body scanned/slice
• Decreases time/slice
• Reconstruction of image depends on speed of table
  movement and tightness of spiral

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Spiral X-ray CT
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Spiral X-ray CT
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CT of Lungs
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Electron Beam Computed Tomography (EBCT)
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ECBT
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EBCT Image of Heart