Biomedical Imaging

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Biomedical Imaging
Dr Mohamed El Safwany, MD.
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Contents

• Mammography

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Mammography
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Intended learning outcome

• The student should learn at the end of this
  lecture Clinical mammographic techniques .

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Introduction and History

• Breast cancer is 2nd only to lung cancer as cause
  of death in women
• Very treatable with early detection!
• Mammography became a reliable diagnostic tool in
  1950s when industrial x-ray film introduced

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Definition of breast cancer

• Cancer that forms in tissues of breast, usually
  ducts (tubes that carry milk to nipple) and
  lobules (glands that make milk).
• Occurs in both men and women (male breast cancer
  is rare)

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Principles Of Breast Cancer

• Pt.s in early stages respond well to treatment
• Patients with advanced disease do poorly
• Earlier diagnosis, better chance of survival
• Mammography is tool for early detection

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Diagnostic Mammogram

• For woman presenting with clinical evidence of
  breast disease, palpable mass or other symptom
• Uses specific projections to
• Rule out cancer
• Demonstrate suspicious area seen on screening
  mammogram

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Breast Anatomy

• Lobule size is affected by age and hormones
• Involution process of decreasing lobule size
  with age and after pregnancy

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Anatomy (contd)

• Breasts vary in size and shape
• Consist of glandular, fat, and fibrous tissue

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Anatomy

• The breast tapers anteriorly ending in the nipple
• Encircled by areola area of pigmented skin
• Breasts are supported by Coopers ligament Female
  breasts are divided into 15 20 lobules

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• Base of breast overlies pectoralis major and
  serratus anterior muscles
• Part of breast extends into axillary fossa

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Typical Mammography Unit
Equipment is C-arm SID is fixed at 24 26
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Mammography Equipment

• Dedicated units have high-frequency generators
• Provide more precise control of kVp, mA, and
  exposure time
• Specially designed to produce high-contrast and
  high-resolution images

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Mammography uses

• Low kVp 25 28
• AEC Automatic Exposure Control
• Anode material made of molybdenum, with rhodium
  target
• Grid with ratio 41, or 51 200 lines/inch

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Magnification

• Increases visibility of small structures
• Radiation dose increases with magnification

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Compression Device

• Compression decreases thickness of breast,
  magnification and scattered radiation
• Increases contrast
• Reduces motion unsharpness
• Reduces dosage

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Compression Device
Made of firm plastic Amount of compression
between 25 and 40 pounds pressure Compression
may be uncomfortable!
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Screen-Film Systems

• Mammography cassettes contain a single screen
• Mammographic film is single emulsion
• Occasionally, extended time processing is used
• (reduces dose and increases contrast)

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Digital Mammography

• State of the art!
• No film or chemical processing
• Images easily sent over internet
• Much better definition

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Procedure

• Complete, careful history and physical assessment
• Take notes on location of scars, palpable masses,
  skin abnormalities, and nipple alterations
• Examine previous mammograms for positioning,
  compression, and exposure factors

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Procedure (cont)

• Patients dress in open-front gown
• Breasts must be bared for imaging
• Cloth will cause image artifact
• Remove deodorant and powder from axilla and
  breast
• Can mimic calcifications on image

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Procedure (contd)

• Explain procedure to pt., including possibility
  for additional projections
• Consider natural mobility of breast before
  positioning
• Support breast firmly so that nipple is directed
  forward
• Profile nipple, if possible

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Positioning
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Procedure

• Apply proper compression to produce uniform
  breast thickness
• Essential to high-quality mammograms
• Place ID markers

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Routine mammography projections

• Craniocaudal (CC)
• Mediolateral oblique (MLO)

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Craniocaudal Projection

• Patient position
• Standing or seated facing IR holder
• Part position
• Elevate inframammary fold to maximum height
• Adjust IR height to inferior surface of breast
• Gently pull breast onto IR holder with both hands
  while instructing patient to press chest to IR
  holder

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Craniocaudal Projection

• Arrange breast on film so nipple is in profile
  and maximum amount of breast tissue is
  radiographed
• CR Perpendicular to base of breast
• Structures Central, subareolar, medial
  fibroglandular breast tissue, posterior pectoral
  muscle

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Craniocaudal Positioning (contd

• Immobilize breast with one hand
• Use other hand to move opposite breast out of
  image
• Shoulder relaxed in external rotation

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Craniocaudal Projection (contd)

• Rotate head away from breast being examined
  (watch out for hair!)
• Lean pt. toward machine
• Compress breast slowly until skin taut

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Mediolateral Oblique Projection

• Position
• Center breast with nipple in profile, if possible
• Hold breast up and out
• Compress breast slowly until taut
• Pull down on abdominal tissue to open
  inframammary fold

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Mediolateral Oblique positioning

• Instruct pt. to hold opposite breast laterally,
  out of anatomy of interest
• Exposure on suspended respiration
• Release compression immediately!

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Mediolateral Oblique

• Open inframammary fold
• Deep and superficial breast tissues well
  separated
• Retroglandular fat well seen
• Uniform tissue exposure
• If compression is adequate

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Mediolateral Oblique

• Degree of obliquity is 30 to 60
• Depends on body habitus
• Tall, thin patients require steeper angulation
• CR perpendicular to base of breast
• Structures lateral aspect of breast and
  axillary tail

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Male Mammography

• Approximately 1000 males develop breast cancer
  every year
• Standard CC and MLO are obtained
• Males not screened- mammogram only if lump
  discovered

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Gynecomastia
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CC view ( lesion)
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Needle Localizations

• Used to localize breast lesions before surgery
• Special, open-hole plate may be used for ease of
  localization
• Plate contains grid to plot coordinates
• Operative stereotactic surgery may be used

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Needle Localization
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Text Book

• David Suttons Radiology
• Clarks Radiographic positioning and techniques

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Assignment

• Two students will be selected for assignment.

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Question

• Define value of compression device in
  mammographic techniques?

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• Thank You

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• Thank you for your attention!