Bone densitometry, or DEXA (dual energy X-ray absorptiometry), is an exam that detects early bone loss by measuring bone mineral density with a low-dose radiation (less than one-tenth of a single view chest X-ray). The X-ray is composed of two energy levels, which are absorbed differently by the bones in the body. A computer is able to determine the quantity of bone mineral present from the amount of X-ray absorption. The spine and hip are the most common sites of measurement.
The bone densitometer is like a large examination table, padded and comfortable. Your name, age, height, weight and ethnicity will be entered into the computer before your test. This information is used to compare your results to a normal reference group. You will be asked to lie on your back, remaining in your normal clothing in most cases. Belt buckles, metal or thick plastic buttons, and metal jewelry will need to be removed from the region being examined. The operator will position your arms and legs for the test.
The needs for bone densitometry vary somewhat depending on the physician and/or medical provider.
General reasons for the procedure include:
Length of procedure:
The procedure lasts for approximately 45 minutes.
Preparation prior to procedure:
There are no injections or oral preparations.
Post exam instructions:
No special instructions.