Contact our breast care nurses 0808 800 6000

Learn about breast x-rays (mammograms), breast ultrasound and other types of imaging used to detect breast changes, and what to expect at your appointment.

1. Mammogram

What is a mammogram?

A mammogram is a breast x-ray. 

You may have a mammogram:

  • During breast screening to check for early signs of breast cancer
  • If you've been referred to a breast clinic to investigate a breast change

What happens during a mammogram?

A mammographer (an expert in taking breast x-rays) will ask you to undress from the waist up and stand in front of the mammogram machine. 

Your breasts will be placed one at a time on the x-ray machine. 

The breast will be pressed down firmly on the surface by a clear plate. 

At least 2 pictures of each breast will be taken, 1 from top to bottom and then a 2nd from side to side to include the part of your breast that extends into your armpit. 

You’ll need to stay in this position while the x-ray is taken. 

3D mammograms

Digital breast tomosynthesis (DBT) is a more detailed type of mammogram used in some hospitals. 

DBT makes 3D images using lower dose x-rays. 

The breast is positioned the same way as when having a mammogram. The x-ray arm rotates and curves around the breast, taking multiple x-ray pictures at different angles. 

The information is then sent to a computer where it makes the pictures into 3D images. This can make it easier to see any overlapping breast tissue more clearly. 

How to prepare for a mammogram

There’s no special way to prepare for having a mammogram. 

It may help to wear a top that’s easy to remove.

If you’re pregnant or think you may be pregnant, let the person doing the mammogram know. 

Is a mammogram painful? 

You may find having a mammogram uncomfortable.

However, it only takes a few seconds and the compression doesn’t harm the breasts.

Are mammograms safe?

Some people worry about the amount of radiation used in mammograms. 

However, they deliver a very low dose of radiation. You’d receive a similar amount flying from London to Australia and back.

Mammograms and younger women

Mammograms are not often used in women under 40. 

Younger women’s breast tissue can be dense, which can make the x-ray image less clear and any changes harder to identify. 

However, for some women under 40, mammograms may still be needed to complete the assessment.

Mammogram results 

As part of breast screening

If you had your mammogram during routine breast screening, your results will be sent to you by letter. 

At a breast clinic appointment 

The breast clinic will let you know how and when you’ll get your results. 

You may hear your results described as a letter and a number. ‘M’ stands for mammogram.

Mammogram results may be described as:

  • M1: normal breast tissue 
  • M2: benign (not cancer) 
  • M3: uncertain but probably benign 
  • M4: suspicious and possibly cancer 
  • M5: cancer

2. Breast ultrasound

What is a breast ultrasound?

An ultrasound scan uses sound waves to produce an image of the breast tissue. 

You may have a breast ultrasound if you have been referred to a breast clinic to investigate a breast change. 

An ultrasound scan is painless. 

It’s generally done in a few minutes but can take longer. 

What happens during a breast ultrasound? 

You’ll be asked to undress from the waist up and lie on a couch with your arm above your head. 

To help get a clear image of the breast, some gel will be spread over the area of the breast first. 

The person doing the scan will move a handheld scanning probe over the breast to look at the underlying tissue. 

The area under your arm may also be scanned. 

Breast ultrasound results

The breast clinic will let you know how and when you’ll get your results. 

You may hear your results described as a letter and a number. 

‘U’ stands for ultrasound. 

Ultrasound results may be described as: 

  • U1: normal breast tissue 
  • U2: benign (not cancer) 
  • U3: uncertain but probably benign 
  • U4: suspicious and possibly cancer 
  • U5: cancer

3. Other types of breast imaging

Although mammograms are usually the best way of detecting any early changes within the breast, sometimes breast clinics use other imaging techniques as well.

An MRI (magnetic resonance imaging) scan uses magnetism and radio waves to produce a series of images of the inside of the breast. An MRI doesn’t expose the body to x-ray radiation.

Contrast enhanced spectral mammography (CESM) uses a special dye to ‘highlight’ areas within the breast in more detail than a standard mammogram.

You may hear about different techniques used to take pictures of the breasts such as thermal imaging and radio waves. These are not routinely used as they are not more reliable than mammograms.

Depending on your test results and symptoms, other types of scans may be recommended.

Was this helpful?

Was this helpful?
Please tell us what you liked about it.
Please tell us why.
We’re sorry you didn’t find this helpful.
Please do not include personal details and be aware we cannot respond to comments.

Quality assurance

Last reviewed in November 2022. The next planned review begins in November 2024.

  • support-cta-icon-telephone

    Call our free helpline

    If you have any concerns about breast cancer, or just want to talk, our specialist nurses are here for you.

    Lines open: Monday to Friday - 9am to 4pm; Saturday - 9am to 1pm

  • support-cta-icon-email

    Explore ways to talk to our nurses

    It can be difficult to talk to someone in person about breast cancer concerns. Explore other ways you can ask a question.

Share this page