About Mammography and Tomosynthesis [DOC]

Description: Mammograms and Tomosynthesis are special x-ray exams of the breast. 

X-ray or radiography, is the oldest and most common form of medical imaging.
An x-ray machine produces a controlled beam of radiation, which is used to create an image of the inside of your body. This beam is directed at the area being examined. After passing through the body, the beam falls on a piece of film or a special plate where it casts a type of shadow. Different tissues in the body block or absorb the radiation differently. Dense tissue, such as bone, blocks most of the radiation and appears white on the film. Soft tissue, such as muscle, blocks less radiation and appears darker on the film. Often multiple images are taken from different angles so a more complete view of the area is available. The images obtained during x-ray exams may be viewed on film or stored digitally and viewed on a computer screen.
Mammogram: A mammogram is an x-ray exam of the breast. A special machine designed specifically to examine breast tissue is used. It takes a different form of x-ray and uses lower doses of radiation than a usual x-ray. Because these x-rays do not go through breast tissue as easily, the mammogram machine has two plates that compress the breast to spread the tissue apart. A more accurate image is obtained with less radiation this way.
Tomosynthesis: Tomosynthesis is a special kind of mammogram that produces a 3-dimensional image of the breast by using several low dose x-rays obtained at different angles. For tomosynthesis, the breast is positioned and compressed in the same way as for a mammogram but the x-ray tube moves in a circular arc around the breast. It takes less than 10 seconds for the imaging. The information from the x-rays is sent to a computer, which produces a focused 3-D image of the breast. The x-ray dose for a tomosynthesis image is similar to that of a regular mammogram.
Preparation for a mammogram or tomosynthesis scan
  • Wear 2-piece clothing (top and pants/skirt) to simplify undressing for exam.
  • Do not apply talc, deodorant, oils or creams on your upper body the day of the exam.
  • Some women experience breast tenderness with their menstrual cycle. If this is the case, she  may want to schedule the exam 1-2 weeks after her period when breasts tend to be less tender.
  • In some women, caffeine-containing products (cola, coffee, chocolate) could make breasts more tender. Women who are sensitive should limit caffeine intake for 2 weeks prior to exam.
  • If you have had prior mammograms performed at other imaging facilities, notify your doctor so that the previous study may be requested for comparison.
  • Tell the technologist if you have breast implants.
  • Women should inform their doctor if they are or may be pregnant or nursing prior to any radiological imaging. Your doctor may recommend another type of test to reduce the possible risk of exposing your baby to radiation.
During the Exam: You will be asked to remove all clothing and jewelry above the waist. You will be given a gown to wear. You will be asked to stand in front of a special mammography x-ray machine. The radiology technician will place the breast between 2 plastic plates. The technologist will press the breast between the two plates. This compression may be uncomfortable for a few seconds while the x-ray is taken. You will be asked to hold very still, without breathing for a few seconds. The technologist will step behind a radiation barrier and activate the x-ray machine. Immediately after the x-ray is taken the pressure is released. Compression needed for a tomosynthesis exam is usually about the same as that for a regular mammogram. For a mammogram, two x-rays of each breast are taken. For a tomosynthesis scan, the breast will be held in place while a special tube rotates around the breast. This should take about 10 seconds. You will not feel the radiation.
Time Required:            15-30 minutes
Noise During Exam:    Minimal clicking or buzzing noises.
Space During Exam:   You will stand next to the x-ray machine with ample space around you.
·        X-ray exams are fast and easy.
·        The equipment used is relatively inexpensive and widely available.
·        The risk of radiation from a mammogram is considered minimal and not significant.
·        Some breast cancers do not show up on mammograms or “hide” in dense breast tissue. A normal (negative) exam is not a guarantee that a woman is cancer-free.  When a mammogram appears normal, but cancer is later found the mammogram is called a false negative exam. The false negative rate is estimated to be 15-20%; higher in younger women and women with dense breasts.
·        A mammogram may show areas that are considered suspicious or not normal. When this happens additional testing is usually suggested, such as additional mammograms, ultrasound, MRI imaging or a breast biopsy. When  the mammogram shows a suspicious change in the breast but no cancer is found, the mammogram is called a false positive exam.. It is estimated that 75-80% of all breast biopsies resulted in benign results (no cancer is found). 
Mammograms and Tomosynthesis exams can be recorded digitally and stored electronically on computers. Some mammograms are recorded on film. A radiologist, who is a physician with specialized training in x-ray and other imaging tests, will analyze and interpret the results of your exam and then send a report to your personal physician. For non-emergency situations, it usually takes a day or so to interpret, report, and deliver the results. Contact your personal physician for information on the results of your exam.
For more information:

This information, as well as additional imaging descriptions, can be found in the “Patients” section of the ACRIN Web site:


Tomosynthesis machine (very similar to a mammography machine. Photo courtesy of Hologic)



  Tomosynthesis image of the breast

 The development of lay imaging descriptions is a project of the 
American College of Radiology Imaging Network
Patient Advocacy Committee.