Mammography (Breast Imaging)
- An introduction to mammography
- How does a mammogram work?
- Who needs a mammogram?
- Preparing for a Mammogram
- How is a mammogram performed?
- Results of a mammogram
- What are the benefits and risks of mammography?
An introduction to mammography
A mammogram is a radiological tool used to image breast tissue. It can detect calcifications, cysts, fibroadenoma (non-cancerous breast lumps) and cancer. Simply an x-ray of the breast, mammography helps to evaluate and diagnose conditions.
This imaging does not prevent cancer, but rather aids in early detection of cancer before it has a chance to spread. Early detection of breast changes through mammography can play an important role in reducing deaths from breast cancer.
In Australia, it is recommended that all women over 50 years of age have a screening mammogram every two years.
How does a mammogram work?
A mammogram is basically an x-ray with a particular focus on imaging the breast. Breast tissue is quite dense; therefore a mammography unit is designed to increase the quality of the pictures without increasing the radiation. This means that only the breast tissue is exposed to the x-rays.
The unit achieves this with a paddle that compresses the breast against a platform to produce even images at various angles. The images are then produced on film using the conventional x-ray method, or created digitally and stored on a computer.
Mammograms aim to detect abnormalities in women with no symptoms, because with early detection there is a better chance of treatment and recovery.
Who needs a mammogram?
In Australia, the National Breast Cancer Centre recommendations regarding screening mammograms are as follows:
- Women aged under 40 years: mammographic screening is not recommended.
- Women aged 40-49 years: women in this age group are eligible for free two-yearly screening mammograms through the BreastScreen Australia program, but they are not targeted by the program. This is because the benefits of screening are not clear. Women should consider the risks and benefits before deciding whether to access mammograms.
- Women aged 50-69 years: these women are encouraged to have free two-yearly screening mammograms through BreastScreen Australia.
- Women aged 70 years and over: women in this age group are eligible for free two-yearly screening mammograms, but they are not targeted by the BreastScreen Australia program. Women should consider the risks and benefits of mammography, including factors such as their general health or other medical conditions.
Women who are at increased risk of developing breast cancer, such as those with a strong family history, should have an individualised surveillance program established in consultation with their doctor.
Preparing for a mammogram
Before scheduling a mammogram is it important to inform your doctor of your family history (especially if any relatives how had breast cancer or cancer), any hormone treatments, surgeries and the results of any prior mammograms. If you can obtain the images of any prior mammograms, make them available to both your doctor and radiologist/technician.
Preparation for a mammogram is much the same as any other radiological procedure. You will be required to remove all jewellery and metal items and it is recommended that you leave your valuables at home. Wear loose fitting clothing, as you will be asked to remove all clothing to the waist and to wear a gown.
In preparing for a mammography there are some points that are important to note. It is recommended that you do not schedule your mammogram for the week prior to your menstrual period, as your breasts may be tender during this time. One week following your period is the best time to schedule a mammogram. It is also recommended that on the day of the exam you do not wear any deodorant, anti-perspirant or talcum powder under your armpits as these products can appear on the mammogram images.
Inform your doctor or radiologist/technician if you suspect or you are pregnant as this is a radiological procedure and there are associated risks to an unborn foetus.
How a mammogram is performed
Once you are in the procedure room, you will be asked to sit in front of the mammography unit.
The rectangular unit is specifically designed to image the breasts. Once the breast is positioned on the platform and the paddle (often made of plastic or Plexiglas) compresses the breast onto the platform.
There are a few reasons why this is beneficial for imaging. Compression evens out the breast tissue so that the tissue can be imaged at the same thickness. It also reduces the amount of radiation needed to penetrate the tissue and it reduces the amount of scatter radiation on the rest of the body.
Compression can be uncomfortable and for some women with sensitive breasts and discomfort may be experienced. It is important to schedule your mammogram at a time when your breasts are least tender. If you experience discomfort, inform your radiologist, who may be able reduce the compression.
During the procedure, the technologist/radiologist will step behind a screen. You may be required to alter your position for various parts of the imaging. There is usually a set of two images, one from top to bottom, and one from the side on both breasts.
The procedure takes approximately fifteen minutes and once the mammogram is complete you may need to enquire whether the results will be forwarded to your doctor or received by you.
Information on re-publishing of our images
Results of a mammogram
Women who are called back to a testing centre with an abnormal mammogram result do not necessarily have cancer. Instead, there is a need for further examination into what the mammogram indicated. It is possible the test was a false positive (ie. returned a positive result, but there is no cancer present). If this is the case, additional mammograms or ultrasounds will confirm the normal result. If the further examinations do not give a definitive answer, then a biopsy may be required to test the tissue for any abnormal cells.
It is important to be aware that mammograms cannot detect all breast cancers. Some may go undetected, for example because the cancer may be the same density as the normal tissue surrounding it. Mammograms work best when they are studied with reference to prior mammograms, where radiologists can track any changes in the breast tissue, as breast cancer develops slowly. Being aware of the normal look and feel of your breasts is also important, as more than half the breast cancers diagnosed in Australia are first detected by a woman or her doctor, not on mammography.
Some abnormal changes to look out for include:
- A lump: If a this lump is something new or unusual and does not go away after your last period you should see your doctor.
- Nipple discharge or changes in the nipple such colour, position or appearance (eg. nipple inverting)
- Changes in the skin’s appearance such as a change in colour or texture, skin dimpling, puckering or depressions (often referred to as an ‘orange peel’ appearance).
- General changes in the shape and appearance of the breast.
Apart from cancer, there are some other conditions that can occur in the breast that can be detected on a mammogram.
- Cyst: A cyst is a collection of fluid, that can occur in the breast and in other areas of the body. Cysts are harmless; they do not cause cancer and are not indicative of cancer. They are thought to occur due to hormone changes during menstruation or hormone replacement. Most cysts, if left to themselves, will resorb and disappear, but sometimes they may need to be drained.
- Calcifications: Otherwise known as microcalcifications, are small mineral deposits in the breast. They may be due dried up secretions, reabsorbed blood, breast trauma or reaction to inflammation. They do indicate changes in the breasts, and although mostly harmless, they may be an indication of breast cancer.
- Fibroadenoma (FA): A fibroadenoma is a non-cancerous (benign) lump of solid tissue. It is round, firm and moves easily under the skin. It can be either painless or painful and tender. A fibroadenoma is not cancerous, cannot become cancerous and does not increase your chances of developing cancer.
- Carcinoma in situ: In situ refers to cancer that has not spread outside the area in which it began. In the breast, this usually means the ducts or the lobules and has not spread into the surrounding tissue or other organs in the body. Ductal carcinoma in situ (DCIS) is the most common of non-invasive breast cancer.
Benefits and risks of mammography
As this is a radiological procedure there is a risk of side effects associated with radiation exposure. However like many other radiological procedures, the risks are minimal due to the reduced amount of radiation used and the specificity of the area of examination. Safety measures are taken for both radiologists and patients, and strict guidelines are enforced.
The diagnostic benefits of mammograms include early detection, treatment and ongoing check-ups for reoccurrences. These significantly outweigh the slight possibility of any side effects from this radiological procedure.
|For more information on breast cancer, types of breast cancer and its investigations and treatments, as well as some useful videos, see Breast Cancer.|
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- Humphrey LL, Helfand M, Chan BK, Woolf SH. Breast cancer screening: a summary of the evidence for the U.S. Preventive Services Task Force. Ann Intern Med. 2002;137(5 Part 1):347-60.
- International Agency for Research on Cancer. Breast Cancer Screening. Lyon: World Health Organization; 2002.
- Nystrom L, Andersson I, Bjurstam N, et al. Long-term effects of mammography screening: updated overview of the Swedish randomised trials. Lancet. Mar 16 2002;359(9310):909-19.
- National Breast Cancer Centre. Position statement: Early Detection of Breast Cancer [online]. 2004 [cited 2006 December 22]. Available from: http://www.nbcc.org.au/resources/documents/EDP_earlydetectionposition0804.pdf
- National Breast Cancer Centre. Breast Imaging: A Guide for Practice [online]. 2002 [cited 2006 December 27]. Available from: http://www.nbcc.org.au/bestpractice/resources/BIG_breastimagingguide.pdf