mammo

• Full-Field Digital Mammography (FFDM)


  Also known as digital mammography, replaces traditional x-ray film with electronics that convert x-rays into digital images of the breast
• FFDM


  • Offers superior dose and contrast performance compared to traditional mammography
  • Particularly effective for women under 50, those with radiographically dense breasts, and pre/perimenopausal women
  • Advanced applications like computer-aided diagnosis and contrast enhancement further improve diagnostic accuracy
• Indirect-Conversion Digital Detectors


  • Uses a two step process similar to screen-film systems for x-ray detection
  • A scintillator absorbs the x-rays and generates light that is then detected by an array of thin-film diodes
  • The diodes convert the light to electric signals that are captured using thin film transistors
  • Thicker scintillators result in decreased resolution
• Direct-Conversion Digital Detectors


  • X-rays are absorbed by the detector and the electric signal is created in a single step
  • Electrons and holes travel along the direction of the electric field lines without lateral charge spreading, resulting in high resolution
  • Selenium (Se) flat-panel detectors are used in direct systems
• Specifications of Digital Detectors

  • Digital Detector Pixels
  • Digital Detector Field of View
• Digital Detector Pixels

  • The layout of pixels in rows and columns, each corresponding to a specific location in the image
  • Higher bit depth represents higher contrast
  • Smaller pixel size increases data but also electronic noise
  • Mammographic imaging requires detection of objects as small as 100-200 μm
• Digital Detector Field of View (FOV)

  • Can be an operator-defined parameter controlling the apparent size of the area to be imaged
  • FOV should be the size of the largest screen-film cassette: 24 × 30 cm
  • If the breast is too large, multiple exposures that "tile" the breast are required
  • Larger detectors can be advantageous for smaller breasts
• Approaches of Digital Mammography

  • Single-Exposure (Standard Digital Mammography)
  • Multiple-Exposure (Advanced Techniques)
• Single-Exposure (Standard Digital Mammography)


  • A single X-ray image of the breast is captured, creating a two-dimensional (2D) flat image
  • Simpler and faster procedure, lower radiation dose
  • Overlapping breast tissue can obscure details and dense breast tissue can appear similar to cancerous lesions
• Multiple-Exposure (Advanced Techniques)


  • Multiple X-ray images are captured from different angles, often with the breast compressed in different positions
  • Techniques like Digital Breast Tomosynthesis create a 3D reconstruction of breast tissue
  • Improved visualization of breast tissue, especially for overlapping structures, can potentially lead to earlier detection of breast cancer
  • More complex and time-consuming, may involve a slightly higher radiation dose
• How the mammography procedure works

  1. Breast is placed on a flat support plate and compressed with a parallel plate

  2. X-ray machine produces a small burst of X-rays that pass through the breast to a detector

  3. Detector transmits electronic signals to a computer to form a digital image
• Mammogram images


  • Low-density tissues appear translucent (darker shades of gray), while dense tissues appear whiter
  • Both a top and a side view are typically taken of each breast
  • Effective radiation dose in women is 0.4-0.7 mSv
• Why the breast needs to be compressed

  • Compression holds the breast in place to minimize blurring from patient motion
  • Compression evens out the breast shape to reduce radiation dose and improve image quality
  • Compression allows all tissues to be visualized in a single plane to avoid obscuring small abnormalities
• How patients should prepare for mammography

  • Schedule when breasts are not tender or swollen
  • Do not wear deodorant, talcum powder, or lotion on the day of the exam
  • Describe any breast symptoms or problems to the technologist
  • Obtain prior mammograms for comparison
• What the mammogram results look like

  • Radiologists look at the size, shape, and contrast of abnormal regions to assess the possibility of malignancy
  • They also look for tiny bits of calcium (microcalcifications) which may signal the presence of a specific type of cancer
  • If a mammogram shows suspicious regions, additional views, imaging studies, or a biopsy may be ordered
• Limitations of mammograms


  • Not 100% accurate in detecting breast cancer
  • False-negative results can occur, especially in women with dense breasts
  • False-positive results are common and can lead to additional testing, anxiety, and cost
• Advantages of digital mammography

  • Radiation dose reductions
  • Image enhancement
  • Time
  • Tele-mammography
  • Productivity
• Disadvantages of digital mammography

  • Expense
  • Additional equipment
  • Connectivity
  • Compatibility
  • Radiologist's computer literacy
• false-positive mammogram looks abnormal even though no cancer is actually present.
• More common in women who are younger, have dense breast, have breast biopsies, have breast cancer in the family, or are taking estrogen.
• The odds of a false positive finding our highest for the first mammogram.
• Woman who have past mammograms available for comparison reduce their odds of a false positive finding by about 50%