Mammography

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Mammography
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Soft Tissue Radiography

• Requires different techniques from conventional
  radiography due to the structures subject
  contrast that is being imaged.

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History of Mammography

• 1920
• First attempt at mammography
• 1950
• First utilized low kVp and high mAs techniques
• 1960
• Development of xero-mammography
• 1990
• Screen film mammography was accepted
• 1991
• ACR volunteer accreditation program
• MQSA federally mandated act

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Breast Cancer

• One of every eight women will develop breast
  cancer during her life

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Types of Mammography

• Diagnostic mammography
• Performed on patients with symptoms
• Screening mammography
• Performed as a preventative measure
• Usually done between the ages of 40 and 50
• Baseline mammogram
• Performed as the first radiographic examination
  of the breast so that comparisons may be made
• Usually done at age of 35

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Breast anatomy

• Fibrous tissue
• Mainly in pre-menopausal women
• Glandular tissue
• Mainly in pre-menopausal women
• Adipose tissue
• Replaces fibrous and glandular tissue in
  postmenopausal women

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Mammographic Imaging System

• Dedicated mammographic imaging systems are
  designed for flexibility in patient positioning
  and have an integral compression device,
  low-ratio grid, AEC and micro-focus x-ray tubes.

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High voltage generation

• Results in 1 voltage ripple with an essentially
  constant potential
• Smaller and less expensive than 3 phase equipment

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Target composition

• Composed of either
• Tungsten
• Molybdenum
• Rhodium

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Focal Spot

• Must be very small
• .3 mm
• .1 mm
• Preferably round
• Anode angle of approximately 23
• Tube tilt of 6 degrees

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Filtration

• The window must be equivalent of .1 mm Al
• Total beam filtration should not be more than .5
  mm Al

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Heel Effect

• Due to compression the heel effect is not
  necessary to image the breast effectively
• A long SID (60 80 cm) is required

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Compression

• The act of flattening the soft tissue to improve
  optical density is important
• Vigorous compression must be used to provide an
  even tissue density to be radiographed.
• Compression will also lower patient dose
• Improves spatial resolution and contrast
  resolution

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Grids

• High Transmission Cellular Grids
• Composed of copper as grid strip material and air
  for interspace material
• Uses a honeycomb design for its construction

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Automatic Exposure Control

• Designed to measure x-ray intensity and x-ray
  quality
• Positioning of photocell depends on patient
  anatomy
• Types
• Ionization chambers
• Solid state diode

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Magnification mammography

• Investigates small suspicious lesions or micro
  calcifications seen on normal mammograms
• Utilizes small focal spots of .1 mm, compression
  devices and patient positioning devices which
  gives a greater OID.

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Screen film mammography

• One of the methods of mammography used today
• The use of single emulsion film with a single
  intensifying screen is the method of choice
• The emulsion surface of the film must always be
  next to the screen and the film must be closer to
  the x-ray tube than the intensifying screen.

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Digital mammography

• Replaces the screen and film with a charged
  couple device (CCD)
• CCD converts light into electrons
• Electrons are sent to the computer where it is
  converted into a digital format and a
  radiographic image is produced on the CRT

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THE END