What is it?

This scan is an X-ray examination, which allows us to take a series of images of the bones in a patient’s body. We use this scan to measure the density of your bones, which shows us how strong your bones are. We do this by using a small, but safe, amount of radiation with the X-ray scanner to take images of your bones. It is a non-invasive scan. 

As we age our bones naturally become less dense. However, if this process is accelerated it may lead to the development of osteoporosis.

Osteoporosis is a condition that weakens a person’s bones, which makes them fragile and more likely to fracture (break). The areas most affected by osteoporosis are the spine, hips and wrists.

In the UK osteoporosis affects approximately one in three women and one in five men. Some contributing factors are:

  • Early menopause
  • Hysterectomy
  • Regular use of steroids
  • Thyroid problems
  • Low calcium intake
  • Heavy smoking
  • Heavy alcohol consumption.

How to prepare for the scan

There is no special preparation for this scan but you can:

  1. Eat and drink as you normally would before the scan
  2. Continue to take your usual medication before the scan
  3. Wear loose trousers, with no metal buttons attached to them, on the day of the scan. If this isn’t possible, we may ask you to change into a gown.

If you think you may be pregnant, or if you are breastfeeding, inform us before the scan.

What happens?

  1. We will ask you to lie on the scanning couch, and we will ask you to lay still. A mechanical arm moves above the area on your body that we are looking at, which is normally your lower back and right hip, and we take a series of pictures of this area. The scan will take approximately 15 minutes
  2. Once this part of the scan has finished, we will let you know the results and you are then free to leave the department.

If you are feeling uncomfortable during the scan, please let our staff know. We will ensure you are relaxed and comfortable during your stay.

After the scan

We will check the pictures from your scan and identify the values for your bone density. We can determine if you have a future risk of developing osteoporosis and discuss this with you before you leave the department.

There are no side effects from this scan, as the amount of radiation you are exposed to is very small and painless.

For information on any side effects or risks, click on the 'Information' tab. 

Asthma is a common lung condition that causes occasional breathing difficulties. There is no cure for asthma but in most sufferers, available treatments keep their symptoms under control. 

Radiation risk

The amount of radioactive material used for this scan is very small, and the benefits of the scan far outweigh the risk. If you have any concerns, talk to the team before the scan.

To make sure that children are not exposed to unnecessary radiation, we ask that you don't bring them into the department with you.


If you are pregnant or think you might be pregnant, you must tell us before the scan because this is something you will not be able to have. You should also tell us if you are breastfeeding or have very young children.

Diabetes and medications

If you are diabetic, you will not need to change your routine for this appointment. Bring in any insulin you may need to the scan, as well as a snack if you need to.

There is no need to change your normal medication routine for this scan. But if you have any concerns or questions, you can call the team before the scan to talk with them.

Side effects, after the scan and results

There are no side effects, you will be able to carry on with any normal tasks, such as driving a car, after your scan. 

How to find us

Royal Brompton nuclear medicine

Level 3, Chelsea Wing, Sydney Street


Monday to Friday, 9am to 5pm

Tel: 020 7351 8666 / 9
Fax: 020 7351 8668
Email: nmadvice@rbht.nhs.uk

Patient advice line: 020 7351 8667

If you have any questions or concerns about the scan please call our patient advice line.

It is an answerphone service – leave a message and we will call you back within 24 hours.

Department head

Kshama Wechalekar

Information for doctors

Please ensure that a valid request form (below) is filled in at the time of booking and sent to the bone densitometry unit.

Request for DEXA scan [doc / 22KB] Bone Densitometry (DEXA)  Department

Location: Basement of Fulham Wing / South Block, Fulham Road, Chelsea, SW3 6HP
Telephone: 020 7351 8666 (9am-5pm for enquiries and bookings)

Scan availability

Mon-Fri, 1.15pm-4pm

Harefield Hospital 

Our nuclear medicine department is located in the ANZAC Centre, which is behind our main reception. 

If you need to speak to the team, call 01895 826 514 (Monday - Friday, 9am to 4pm).