A bone density scan is an imaging test that uses x-rays and computer technology to measure bone density. A bone density scan is also called a bone densitometry or dual energy x-ray absorptiometry (DXA) scan.
A bone density scan is done to:
Bone loss can result from:
Osteoporosis is a condition in which the bone mineral density is lower than normal. The risk factors for osteoporosis include:
A bone density scan is usually done as an outpatient procedure in the x-ray (radiology) department of a hospital or clinic. Depending on the number of areas being scanned, the test takes between 5 and 20 minutes.
During the test:
X-rays involve low levels of ionizing radiation, which has the potential to cause cancer and other defects. As with any x-ray test, there is some radiation exposure, but the amount from a bone density scan is very little (less than one-tenth the amount of radiation used in a chest x-ray) and poses no danger.
X-rays are strictly monitored and controlled to make sure they use the smallest amount of radiation possible. The expected benefits of the x-rays must always outweigh any possible risk for the x-rays to be done.
Bone density scan results tell the doctor how dense the bones are. The way in which the results are used depends on the age of the person. A bone density scan does not tell a person that they will have a bone fracture, but it provides an idea about how great their risk is.
For people over age 50, the results of the bone density scan are combined with age, gender, history of certain fractures and history of using a glucocorticoid (for example, prednisone). Together, these factors are used to determine a person’s chance of breaking a bone over the next 10 years. Risk is classified as:
For people under 50 years of age, absolute risk is not determined. Instead, their results are compared to values that would be expected for a young, healthy person and are classified as being either normal or reduced.
The doctor will decide whether further tests, procedures, follow-up care or treatment to manage bone loss are needed.
Being prepared for a test or procedure can reduce anxiety, increase cooperation and help the child develop coping skills. Parents and caregivers can help prepare children by explaining to them what will happen, including what they will see, feel and hear during the test.
The preparation you can provide for this test depends on the age and experience of the child. See the following for more age-specific information on helping children cope with tests and treatment.