How does the densitometer work?
The bone densitometer uses small amounts of x-ray to produce images of the spine, hip, or even the whole body. The x-ray is composed of two energy levels which are absorbed differently by the bones in the body. The technical term for the method is “dual-energy x-ray absorptiometry”, or DEXA. A computer is able to determine from these differences how much bone mineral is present. The spine and hip are measured because that is where osteoporotic fractures occur most.
What can I expect during my bone densitometry test?
The bone densitometer is like a large examination table. It is 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, which is painless and typically takes one to ten minutes. You just need to lie still and breathe normally.
Is the test safe?
Even though x-rays are used, the amount absorbed by the patient is only about 1/10th of that received from a chest x-ray. Other x-ray procedures have even higher x-ray doses. The x-ray dose from the bone densitometry test is comparable to the naturally occurring radiation your are exposed to in one week.
Caution: Even though the x-ray dose from the bone densitometry test is very low, please inform the operator if you are pregnant or might be pregnant before your test.