Blog and News

How Does A DEXA Scan Measure Bone Density?

How Does A DEXA Scan Measure Bone Density?

Dual Energy X-ray Absortiometry, or DEXA scanning, is currently the most widely used method to measure bone mineral density. It has become the most widely used method for measuring bone mineral density for several reasons.

When compared with radiographic absortiometry or single energy x-ray absortiometry, DEXA scanning more precisely documents small changes in bone mass and is also more flexible since it can be used to examine both the spine and the extremities. A scan of the spine, hip or the total body requires only one, two or four minutes respectively.


Qualitative computed tomography (QCT) is the only technique that can directly measure bone density and volume but can distinguish trabecular from cortical bone. DEXA scanning is less expensive, exposes the patient to less radiation and is more sensitive and accurate at measuring subtle changes in bone density over time or in response to drug therapy than is QCT.


Studies using DEXA scanning have shown that people with osteoporosis have substantially lower bone density measurements than normal, age-matched people. Bone mineral density is widely accepted as a good indicator of bone strength.


A DEXA scanner is a machine that produces two X-ray beams, each with different energy levels. One beam is high energy while the other is low energy. The amount of X-rays that pass through the bone is measured for each beam. This will vary depending on the thickness of the bone. Based on the difference between the two beams, the bone density can be measured.


A DEXA scan report compares the patient’s bone mineral density values with those of young normal patient (T score) and with age matched normal patient (Z score). By comparing a patient’s bone density against there peers, a low score indicates there may be a reason other than age related bone loss.


At present, DEXA scanning focuses on two main areas — the hip and spine. Although osteoporosis involves the whole body, measurements of BMD at one site can be predictive of fractures at other sites. Scanning generally takes 10 to 20 minutes to complete and is painless and noninvasive.


If your physician has ordered a bone density test or DEXA scan, consider Fox Valley Imaging for the procedure. Our clean, modern facility is easy to find, has plenty of parking and our technicians and radiologist have extensive experience and a kind bedside manner. Call us at (630) 416-1300 to schedule an appointment.

Recent Posts

17 Apr, 2024
Are Steroid Medications and Lifestyle Factors Triggering the Need for Bone Density Scans?
11 Apr, 2024
3D MRI Prostate mapping is a new procedure which offers a number of improvements compared to the traditional TRUS (transrectal ultrasound) biopsy for people who have prostate cancer. TRUS guided biopsies have been the go-to way of diagnosing prostate malignancy for the last 20 years, but this procedure is quite invasive, and it is not very precise.
03 Apr, 2024
A lot of people are at risk of heart disease and do not even know it. The good news is that there are simple procedures which can help to identify people who are at risk of heart disease so that they can take precautions to reduce their risk, and get the medical care that they most need.
28 Mar, 2024
Here is a comprehensive guide to help you understand how your Calcium Score could be an important indicator of your risks of suffering from a heart attack. Your Calcium Score can be found after performing a CT scan of your heart. This score is calculated by measuring the quantity of calcium that is present in the arteries that take blood to your heart, also known as the coronary arteries.
21 Mar, 2024
Osteoporosis is a disease of the bones that happens when your body loses too much bones, makes too little bone material or both. As a result, your bones become weak and may break more easily.
Share by: