What is Bone Densitometry?
The Centre offers DEXA (Dual Energy X-ray Absorptiometry) bone densitometry for accurate assessment of bone mineral density.
Bone densitometry, commonly known as a DEXA or DXA scan, is a low-dose X-ray test that measures the amount of calcium and other minerals packed into a segment of bone. It is the most widely used and most accurate method of measuring bone mineral density (BMD), and is typically performed on the lower spine and hips. The test is quick, painless and non-invasive, using a very small amount of radiation — far less than a standard chest X-ray.
Why is the test performed?
A bone densitometry scan is mainly used to diagnose osteoporosis and osteopenia (low bone density that can lead to osteoporosis) before a fracture occurs, and to monitor bone health over time. It helps your doctor to:
- • Detect low bone density before a fracture happens.
- • Confirm a diagnosis of osteoporosis if a fracture has already occurred.
- • Predict future fracture risk.
- • Monitor the effectiveness of osteoporosis treatment over time.
The test is generally recommended for postmenopausal women, men over 50 with risk factors, individuals on long-term steroid therapy, and anyone with a family history of osteoporosis or a previous fragility fracture. Your doctor will advise how often you may need repeat scans.
How to prepare
- • No special preparation is usually required.
- • Avoid calcium supplements for at least 24 hours before the test.
- • Wear loose, comfortable clothing without metal zips, buttons or buckles.
- • Remove jewellery, belts and any metal objects near the area being scanned.
- • Inform staff if you are or may be pregnant, or have had a recent X-ray, CT scan or contrast study.
What happens during the scan?
You will be asked to lie down on a padded table. The scanner arm passes over your body — usually over the lower spine and hip — without touching you, sending a low-dose X-ray beam through the bone. You will need to stay still for a few moments while each area is scanned. The entire procedure is painless and typically takes about 10 to 20 minutes. There is no need for anaesthesia or sedation, and you can resume your normal activities immediately afterwards.
FAQs
Is a DEXA scan painful?
No. The scan is completely painless. You simply lie still on a table while the scanner arm passes over you.
How much radiation is involved?
The radiation dose is very low — significantly less than a standard chest X-ray — making it safe for routine and repeat screening.
How long does the test take?
Most bone densitometry scans take about 10 to 20 minutes to complete.
What do the results mean?
Results are usually reported as a T-score, which compares your bone density to that of a healthy young adult. A T-score of -1.0 or above is considered normal, between -1.0 and -2.5 indicates low bone mass (osteopenia), and -2.5 or below indicates osteoporosis. Your doctor will interpret the report along with your clinical history.
Who should get this test?
It is commonly recommended for postmenopausal women, men over 50 with risk factors, people on long-term steroid medication, and anyone with a family history of osteoporosis or a previous fracture from a minor fall. Your doctor can advise if and when you need one.
Do I need to fast before the test?
No fasting is required. You should only avoid taking calcium supplements for 24 hours before the scan.