Diagnostic Mammography

Authors: Dr Helen Frazer*
                            A/Prof Liz Wylie *

What is diagnostic mammography?

A diagnostic mammogram is an X-ray examination of the breasts. This is carried out when a person, their doctor or another health professional discovers unusual signs or symptoms in one or both breasts; that is, a lump, tenderness, nipple discharge or skin changes. The mammogram confirms whether the changes are benign (non-cancerous) and no treatment is needed, or whether the changes indicate possible breast cancer and further tests and treatment may be required.

Why would my doctor refer me to have this procedure?

Your doctor would refer you for this procedure, as mammography is a sensitive test to show breast cancers and benign causes of breast symptoms, particularly in women aged older than 40 years.

How do I prepare for diagnostic mammography?

If you have menstrual or monthly periods, it is best to have your diagnostic mammogram appointment 1 week after the start of your period. The breasts will not be as tender at this time and you will not feel as much discomfort or pain for the few seconds when the breasts are pressed between two plates to take the X-ray pictures or images.

If you have breast implants, please let the hospital, clinic or radiology practice know, so they can schedule a longer appointment. The presence of implants needs more time to make sure clear images are taken.

When you make the diagnostic mammogram appointment, you will be told not to wear any deodorant, perfume, lotion or talcum powder on the day of your appointment, because these substances may show up as shadows on your mammogram. If you have had previous mammograms at other centres, please bring them with you to your appointment, so they can be compared with the new diagnostic mammogram. It is better to wear a two-piece outfit, so you only need to undress from the waist up.

What happens during a diagnostic mammography?

When you have undressed, a radiographer will explain the mammography procedure to you and ask a few questions; for example, ‘have you had a prior mammogram?’, ‘do you have a history of prior breast procedures’, ‘do you have a family history of breast disease?’. Your breasts will then be put, one at a time, between two special plates and compressed (pressed down) between the plates by the X-ray machine for a few seconds while X-rays are taken. Two views of each breast are taken as a minimum.

The mammography and the compression are carried out by a specially trained radiographer (medical imaging technologist). While the compression may be uncomfortable and perhaps painful, it lasts only seconds. Without compression, the X-rays would be blurry, which makes it hard to see any abnormality. Compression also reduces the amount of radiation required for the mammogram.

Are there any after effects of diagnostic mammography?

After effects are rare. You may experience breast tenderness, bruising or, very occasionally, minor splitting of the skin if your skin is fragile. Please tell the radiographer who is doing the test if you tend to bruise or have skin that breaks easily.

How long does diagnostic mammography take?

Standard diagnostic mammography takes between 10–15 minutes. Sometimes extra views are taken, which will take longer. If you have breast implants, the mammography will take approximately 30 minutes, because it takes more time to make sure clear images are taken.

What are the risks of diagnostic mammography?

Like all X-rays, having a mammogram exposes you to some radiation, but only a small amount. Scientists estimate that there is less than a 1 in 25,000 risk of a mammogram causing breast cancer (see InsideRadiology: Radiation Risk in Medical Imaging for Adults and Children).

Such risk is far outweighed by the benefit of early detection of breast cancer, significantly reducing the death rate from the disease and providing better treatment options. The Health Protection Agency of the United Kingdom estimates the risk of an additional cancer in a lifetime from a single mammographic examination to be in the low-risk range: 1 in 100,000 to 1 in 10,000.1 The risk of developing cancer from a mammogram is no greater than developing cancer from exposure to the natural background radiation accumulated from the normal environment in 1 year.

If you have breast implants, there is an extremely small risk of damage to the implant.

For women with a lump that can be felt, it is important to note that mammography does not detect all breast cancers, even when the cancer has caused a lump that can be felt. In such a circumstance, a normal mammogram does not mean that the lump can be ignored. In this situation, other diagnostic tests, such as breast ultrasound with needle biopsy, may be necessary to find out the cause of the lump.

Dense breasts:

You may have heard of women having dense breasts. Dense breasts are where there is a large amount of glandular tissue present that could mask and obscure the detection of breast abnormalities.

If your doctor believes you may have dense breasts and you have a significant breast symptom, or a strong history or personal history of breast cancer, they may recommend you have a breast ultrasound (see InsideRadiology: Breast ultrasound) as well as a mammogram.

What are the benefits of diagnostic mammography?

The benefits of mammography far outweigh the risk. Multiple scientific studies have provided plenty of evidence that early diagnosis and treatment of breast cancer can save lives.

Early detection increases the likelihood of a cancer being successfully treated and often allows for greater treatment options.

Who does the diagnostic mammography?

The X-rays are taken by a radiographer (medical imaging technologist), who has received specialist training in the field of mammography. The mammograms are then read and interpreted by a radiologist (a specialist doctor with training in breast imaging), who will provide your referring doctor with a report of the examination.

Where is diagnostic mammography done?

Diagnostic mammography is carried out in hospital radiology departments, breast clinics or private radiology practices.

When can I expect the results of my diagnostic mammography?

The time it takes your doctor to receive a written report on the test or procedure will vary depending on:

  • the urgency with which the results are required by your doctor;
  • the complexity of the test or procedure;
  • whether more information is needed from your doctor before the test or procedure can be interpreted by the radiologist;
  • whether you have had previous X-rays or other medical imaging that need to be compared with this test or procedure (this is commonly the case if you have a disease or condition that is being assessed as to its progress);
  • how the report is sent to your doctor (i.e. phone, email, fax or mail).

Please feel free to ask the private practice, clinic, or hospital when the written report will be provided to your doctor.

It is important that you discuss the results with your doctor, either in person or on the telephone, so that they can explain what the results mean for you.


  1. The Health Protection Agency, X-rays – How safe are they?, May 2001, https://www.phe-protectionservices.org.uk/cms/assets/gfx/content/resource_3317cs2c758933af.pdf
*The author has no conflict of interest with this topic.

Page last modified on 31/8/2018.

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