Quality of the radiographic image

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Quality of the radiographic image

• Contrast
• Image geometry
• Characteristics of the x-ray beam
• Image sharpness and resolution

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Perception of the radiographic image

• Partial images-we all see the same partial images
  but we dont necessarily perceive the same object
• Contrast
• Context

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Effect of partial image
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The effect of contrast
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The effect of context
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Image geometry

• Positioning of the film, object and x-ray beam
• Focal spot size and principle of line focus
• Focal spot-object distance (FSOD), object-
• to film-distance (OFD)

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Ideal image geometry requirements
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Focal spot size, heat distribution and image
sharpness

• Focal spot 1mm
• Heat needs to be distributed over as large
• as possible area
• Principle of line focus

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Focal spot-to film-distance(FSFD)
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FSFD

• Increasing the distance between the focal
• spot and the object results in an image
• with increased sharpness and less
• magnification of the object

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Object-to film- distance (OFD)
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• Decreasing the distance between the
• object and the film increases the
• sharpness and result in less magnification
• of the object

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Image shape distortion
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Contd
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Bisecting angle technique-shape distortion
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Contd