elgen said:
Dear all,
Micro-calcification is an indication of breast cancer at its early stage and appears as bright spots in X-ray mammograms.
My question is that X-ray attenuates much in calcium than in regular soft tissue in the human breast, e.g. glands, milk duct, adipose, etc., should not micro-calcification appears as faint spots in mammograms?
Confused,
elgen
Calcium is a metal and breast calcifications do, indeed, attenuate low energy x-ray more than adjacent soft tissue. In classic x-ray images, where ionizing radiation hits the film, the film is blackened; where no x-rays strike the film, the film is clear. Since calcium stops x-rays, just as in images of bones, the calcium appears "white" (from the light of the view box shining through clear film) and the soft tissues appear relatively dark (where fogged, blackened film stops the passage of light from the view box).
Modern mammography is now usually done with digital imaging. No film is involved. The x-rays strike a digital camera, causing a bright spot. But that is somewhat arbitrary as a digital image can be inverted b/w or w/b. Digital images are also affected by image processing algorithms (filters, noise reduction, contrast, window width, window level, etc.
Most calcifications in the female breast are benign. When the good Lord invented the female breast, it was to make milk. Milk is rich in -- yes -- calcium. Metabolically, what breast gland cells do for a living is concentrate calcium.
Here is a digital image of a cancer with calcifications and with a small metal marker clip (following needle biopsy). Air - black, Fat - dark gray, soft tissue - light gray, metal (including calcium) white.
