What is bone densitometry?

Bone densitometry, also known as dual-energy X-ray absorption (DEXA), is a painless test to help your doctor diagnose osteoporosis or to determine whether certain steps should be taken to protect your bone health. The results from your DEXA exam will be compared with the peak bone mass of the average healthy same-sex adult. A bone densitometry exam is more precise than conventional diagnostic imaging (X-rays) and can help to diagnose bone loss at an early stage.

Discuss with your doctor about having a bone densitometry test if you have one or more of the following risk factors for osteoporosis:

  • Your mother, grandmother or another close relative had osteoporosis or bone fractures
  • You have low body weight, a slight build or a light complexion
  • You have a history of cigarette smoking or heavy drinking
  • You experienced the early onset of menopause, naturally or surgically (early is defined as before the age of 45)
  • Over a long period of time, you have taken medication that accelerates bone loss such as corticosteroids for treating rheumatoid arthritis or other conditions, or some anti-seizure medications
  • You have already experienced a bone fracture that may be the result of thinning bones
  • Your ethnic background is Caucasian or Asian

Preparing for a bone densitometry exam

You may eat normally on the day of your exam; however, you should avoid taking calcium supplements for at least 24 hours before the test. You will be asked to remove any ear or body piercings or other metal or electronic objects from your body before the exam as these objects interfere with the quality of the images.

Generally, the portion of your body that is being examined will be undressed; you may be asked to wear a hospital gown to cover yourself during the exam.

For your safety

Tell your doctor if you are pregnant or suspect you may be pregnant. Your doctor may decide to postpone the exam or use an alternative exam such as an ultrasound to reduce the possible risk of exposing your baby to radiation.

Tell your doctor if you have recently had a barium exam or have been injected with a contrast medium for a CT scan or had a nuclear medicine exam. Your doctor may wish to postpone a DEXA scan for five to seven days.

What to expect during a bone densitometry exam

The DEXA bone density exam typically takes 15 to 20 minutes to complete.

Our technologist will prepare and guide you by explaining the procedure, helping you remove clothing or piercings and positioning you to ensure the highest-quality images are obtained from your exam.

The technologist performs the exam and can always see and hear you. The technologist may ask you to, and assist you with, change positions to obtain images from multiple areas of interest.

The DEXA exam has two parts: one to assess your spine and the other to assess your hips. For the spine scan, you will lie flat on your back with your legs elevated. For the hip scan, you will lie flat on your back with your legs outstretched. Both hips are scanned unless you have had a hip replacement, in which case the hip without replacement would be scanned. If both hips have been replaced, only your spine will be scanned.

For both parts, the detector portion of the machine will slowly pass over the area without direct contact with your body. At no time is your body confined or enclosed or your face covered.

When your exam is complete, you can leave and resume regular activities.


A radiologist will review your exam images and report the findings to your doctor. Your doctor will then discuss the findings and next steps with you.