Mammography is an imaging technique that uses X-rays to provide a picture of the internal structure of the breast. The X-rays can show abnormal growths or changes in breast tissue before they can be found by any other method, including breast self-examination.
On this page:
- About mammography
- Mammogram as a screening tool
- Mammography and radiation exposure
- Minimizing your risk
- Government of Canada's role
- More information
Mammography is an imaging technique that uses X-rays to provide a picture of the internal structure of the breast. Mammograms can be done for diagnostic or screening purposes.
Your doctor may recommend a diagnostic mammogram if you have a symptom that needs to be investigated, such as a lump in your breast.
A screening mammogram looks for signs that breast cancer may be developing, even though you have no symptoms.
Breast cancer is one of the leading causes of cancer-related deaths in Canadian women. In 2017, there will be an estimated 26,300 new cases in women aged 20+ and 5,000 deaths from breast cancer in Canada. About 13% of Canadian women (one in eight) will get breast cancer at some point in their lives. The risk of developing breast cancer increases as women get older.
When breast cancer is detected early through a mammogram, there are better treatment options and a greater chance for a successful recovery.
Mammogram as a screening tool
The X-ray images used in mammography can show abnormal growths or changes in breast tissue before they can be felt. In addition to detecting breast cancer in its early stages, mammography is also an effective way to determine that women do not have breast cancer. This makes mammography the best tool available to screen for breast cancer in women.
Mammography is the only technique proven to be safe and effective in screening for breast cancer, and mammography equipment is the only imaging technique licensed by Health Canada for breast cancer screening.
If a suspicious lesion shows up on a mammogram, other techniques - such as ultrasound, biopsy magnetic resonance imaging (MRI) and laser scanning - may be used for further investigation. However, none of these other techniques is recommended for screening purposes at this time.
New technologies are being evaluated to see if they are safe and effective. Also, claims that thermography is useful in diagnosing breast cancer have not been proven, and thermography equipment is not licensed for breast cancer screening in Canada.
Mammography and radiation exposure
The risk of getting cancer from a mammogram is extremely low. An X-ray machine is used for the mammogram and the radiation dose with a mammogram is quite low. Your body can usually repair the few cells that might be damaged by the X-rays. The benefit of early diagnosis and treatment for breast cancer far outweighs the risk of the small amount of radiation received during a mammogram.
Minimizing your risk
There is plenty of evidence that early detection and treatment of breast cancer saves lives.
All women should talk to their doctor about the risk of getting breast cancer. This is especially important for women with a family history of early onset breast cancer; if this is your situation, you may benefit from having mammograms, as well as genetic screening.
Women who are 50 to 74 years of age should have screening mammograms every two to three years. Ask your doctor about this or contact a breast cancer screening program in your province or territory.
Remember, mammography is the only imaging technique proven to be safe and effective for breast cancer screening. Do not take a chance with your health by relying on unproven, alternative technologies to screen for breast cancer.
Government of Canada's role
Health Canada regulates the importation and sale of medical devices and radiation emitting devices in Canada, through the Food and Drugs Act, the Radiation Emitting Devices Act , and the Medical Devices Regulations. These Acts and Regulations assure the safety, effectiveness and quality of medical devices, including mammography equipment, when they are used for their licensed purpose. Health Canada also provides guidance to mammography facilities through the Radiation Protection and Quality Standards in Mammography - Safety Procedures for the Installation, Use and Control of Mammographic X-ray Equipment: Safety Code 36.
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