A bone densitometry (DEXA – Dual Energy X-ray Absorptiometry) scan is performed using low-dose x-rays with two distinct energy peaks that are absorbed by soft tissue and bone respectively. A total density value is obtained. By subtracting the soft tissue density value from this total, the bone mineral density is obtained. The data is processed on a computer and the bone density measurements are displayed on the monitor.
Two scores are of interest. The T score compares one’s bone density to that of a young adult of same gender with peak bone mass. This is used to estimate potential risk of skeletal fractures. The Z score compares one’s amount of bone to that of others with same age, size and gender.
BMD is quick and painless and the preferred procedure for diagnosing osteoporosis.

Discontinue any Calcium supplements for at least 24 hours prior to the examination.
The study should not be done within 10 to 14 days of any previous barium examination or radiological examination requiring the intravenous administration of contrast e.g. CT, IVP, MR or radioisotope scan.
No other dietary limitations.

Inform the technologist of any possibility of pregnancy or recent intravenous administration of contrast or barium study as described above.
Prior lumbar spine or hip surgery or some bone maladies may influence the results and these should be mentioned to the technologist.

Patients will be required to remove their clothing and jewelry prior to the examination and wear gowns provided. Any garments that contain metal zippers, belts or buttons and jewelry may interfere with x-ray images.
During the examination, one lies on a flat, padded bed while a mechanical, arm-like device passes over the body, emitting low-dose radiation. It usually takes 5 to 10 minutes. The arm-like device never touches the body.
Regions that enjoy specific attention include the lumbar vertebrae, the femoral necks and the wrists and forearms.

Provide the technician with a detailed medical history, referring specifically to family history of osteoporosis; medical conditions like diabetes, thyroid, parathyroid, liver or kidney diseases; medications like Prednisone, barbiturates, certain anti-seizure drugs and Eltroxin.
Cooperation with the technician is essential to the success of the procedure. Patient must remain stationary throughout the short examination.

Make an appointment beforehand to avoid long waiting periods.
Be at the radiology department at least 20 minutes before the scheduled time of examination to complete the necessary administrative tasks.