Dual-energy X-ray absorptiometry is a means of measuring bone mineral density using spectral imaging. Two X-ray beams, with different energy levels, are aimed at the patient’s bones. When soft tissue absorption is subtracted out, the bone mineral density can be determined from the absorption of each beam by bone. DEXA is the most commonly used and the most standard method for diagnosing osteoporosis, to assess an individual’s risk for developing osteoporotic fractures.


• This procedure requires exposure to ionizing radiation.
• If there is a possibility that you are pregnant, please inform the Nuclear Medicine staff.
• If the patient is undergoing investigations with radiopharmaceuticals on the same day, the DEXA should be done first. Both 99mTc and 18F-FDG can influence the DEXA results.
• For 7 days before BMD scan: No radiographic contrast (Iodine & Barium) gastrointestinal or lumbar studies.
• For 3 days before BMD scan: No Calcium & Vitamin supplements.
• Before leaving home/ward for study: No metal or dense objects in clothing or on surface of
your body as they may affect the accuracy of the test.
• Fasting is not required for this procedure.
• Before Scan: Please inform the Nuclear Medicine staff and the doctor if you have internal
hardware e.g. hip prosthesis, lumbar metal rods, and screws.


What you need to know about Nuclear Medicine
Basic Introduction to Nuclear Medicine