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The Mammography Procedure  Two kinds of mammograms are available: (1) screen-film (or analog)
mammography, and (2) full field digital mammography:
In screen-film mammography,
x-ray beams are captured on a film cassette. Special x-ray machines
developed exclusively for breast imaging are used to produce mammography
films. These machines use very low doses of radiation and produce high-quality
x-rays. The procedure produces an image of the breast tissue on a film,
which is examined by a radiologist for abnormalities or
evidence of cancer.
In full
field digital mammography, x-ray beams are captured
on specially designed digital detectors. The digital detector converts
the x-ray beams into electronic signals, which are then sent to a computer.
The radiologist can review the digital mammogram on a high-resolution
computer monitor, like the ones shown above.
When a woman has a mammogram, she must undress
above the waist and wear an open wrap, which is provided by
the mammography facility. A breast-imaging
technologist will place the patient in front of the machine
and position each breast, one at a time, on the mammography equipment. The technologist will position the patient and the breast in the appropriate location for obtaining the best image of the breast. A paddle is then used to gently compress the breast so that the tissue is flattened. 
Compressing the breast is necessary to obtain
the best image. Compression thins and evens the breast tissue,
so that a lower x-ray dose can be used. Even distribution of
breast tissues reduces x-ray scatter, or the spread of radiation
from the targeted tissue, which provides a better quality image.
Compression also prevents the breast from moving during the
procedure, thus reducing or eliminating blurred images. Breast
compression lasts for a few seconds. It is uncomfortable, but
should not be painful.
When the breast is positioned and compression
is complete, the technologist will leave the room or step behind
a screen. Once shielded, the technologist
will turn on the x-ray source to transfer the image of the
breast onto the x-ray film or the digital detector. The process
of positioning and radiating is repeated for additional views of the same breast
and for the other breast.
If a screen-film examination is being conducted,
the technologist will take all of the x-rays needed for the examination.
She will then develop the films before the patient leaves, to make
sure each film shows the right view and exposure.
In digital mammograms, the image for each exposure will appear on
the technologist's computer screen, and she will be able to make
sure each image is acceptable before positioning the patient for
the next view.
The entire procedure for screening mammography should take 15
to 20 minutes for a screen-film examination and slightly less for
digital mammography. The procedure may take longer if additional views are
needed, as is the case in diagnostic mammography or for mammography of women
with breast implants. Breast implants create a unique imaging situation,
because some breast tissue will be covered by the implant and cannot be seen
on x-rays. To compensate for this, additional films are taken, to allow as
much breast tissue as possible to be imaged.
The mammography films are interpreted
by a radiologist, who will look for abnormalities and compare the new films
to previous mammograms, to detect any changes. The radiologist prepares a
report for your mammography facility. The mammography facility is responsible
for notifying the patient of the results.
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