Bone Mineral Densitometry
Bone Mineral Densitometry

Bone mineral densitometry (BMD), also called dual-energy x-ray absorptiometry (DEXA) is an x-ray examination used to measure bone loss. DEXA is today’s established standard for measuring bone mineral density.

BMD is often used to diagnose osteoporosis, a disease wherein a loss of bone tissue occurs. This makes bones brittle and more prone to breakage. Some common causes of osteoporosis includes:

  • Lack of physical activity
  • Inadequate calcium in the diet
  • Menopause
  • Simultaneous illness, hormonal irregularities and thyroid disorders

BMD is also effective in tracking the effects of treatment for osteoporosis and other conditions that cause bone loss.


You will be asked to lie on your back on a couch and keep still while an x-ray detector comes over for your test. The x-ray equipment is energised and the detector measures the rays that come through the bone. This information is sent to a computer that calculates a score of the average density of the bone. A low score indicates that the bone is less dense than it should be, some material of the bone has been lost, and is more prone to fracture.

The bones commonly scanned are the vertebrae (backbones), hip and wrist. These are the bones common to fractures due to osteoporosis. The scan is painless and takes 15-20 minutes.

Your test results will be in the form of two scores:

  • T score – This number shows the amount of bone you have compared with a young adult of the same gender with peak bone mass. A score above -1 and -2.5 is classified as osteopenia, the first stage of bone loss. A score below -2.5 is defined as osteoporosis. The T score is used to estimate your risk of developing a fracture.
  • Z score – This number reflects the amount of bone you have compared with other people in your age group and of the same size and gender. If this score is unusually high or low, it may indicate a need for further medical tests.

Small changes may normally be observed between scans due to differences in positioning and usually are not significant.

Benefits and Risks


  • DEXA bone densitometry is a simple, quick and non-invasive procedure.
  • The amount of radiation used is extremely small – less than one-tenth the dose of a standard chest x-ray.
  • DEXA bone density testing is the most accurate method available for the diagnosis of osteoporosis and is also considered an accurate estimator of fracture risk.


  • The effective radiation dose from this procedure is about 0.01 mSv, which is about the same as the average person receives from background radiation in one day.
  • Women should always inform the radiographer if there is any possibility that they are pregnant.
Bone Mineral Densitometry is available at:

Radiology Department,
Gleneagles Hospital

6A Napier Road,
Singapore 258500
(65) 6470 5730
Fax: (65) 6470 5749

Radiology Department,
Mount Elizabeth Novena Hospital

38 Irrawady Road, Level 2,
Singapore 329563
(65) 6933 1188
Fax: (65) 6933 0526

Radiology Department,
Parkway East Hospital

321 Joo Chiat Place
Singapore 427990
(65) 6470 5749
Fax: (65) 6340 8670

Radiologic Clinic,
Mount Elizabeth Medical Centre

3 Mount Elizabeth, #01-01
Mount Elizabeth Medical Centre
Singapore 228510
(65) 6731 2727
Fax: (65) 6235 5279

Radiologic Clinic,
Breast Imaging Centre

290 Orchard Road
#07-04 Paragon
Singapore 238859
(65) 6732 1166
Fax: (65) 6732 5933


Visit this FAQs page for more information.



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