A bone density scan can detect thinning bones at an early stage. If you already have osteoporosis, bone scans can also tell you how fast the disease is progressing.
But an abnormal bone scan can create as many questions as it answers. Who should get a bone density scan, and what do the results mean? If your bone density is below normal, what can you expect, and what should you do?
Reality:Osteoporosis and bone disease often result in painful and debilitating fractures. These injuries can have significant long-term consequences, leaving the individuals with chronic pain, loss of height, and impaired ability to do the things they need to do to care for themselves, such as dress, bathe, walk, and take care of their household.
Many osteoporosisfractures -- about 300,000 every year -- are hip fractures, which are particularly dangerous and debilitating. One in four hip fracture...
Most bone scans use a technology called DEXA (for dual energy X-ray absorptiometry). In a DEXA scan, a person lies on a table while a technician aims a scanner mounted on a long arm. (Think of the machine that X-rays your teeth at the dentist; the difference is that this test uses very low energy radiation.)
"DEXA currently is the easiest, most standardized form of bone density testing, so that's what we use," says Mary Rhee, MD, MS, an endocrinologist and assistant professor of medicine at Emory University in Atlanta.
The DEXA scanner uses beams of very low-energy radiation to determine the density of the bone. The amount of radiation is tiny: about one-tenth of a chest X-ray. The test is painless, and considered completely safe. Pregnant women should not get DEXA scans because the developing baby shouldn’t be exposed to radiation, no matter how low the dose, if possible.
Other less commonly used technologies can measure bone density. They include:
Variations of DEXA, which measure bone density in the forearm, finger, or heel.
Quantitative computed tomography (QCT). Essentially a CAT scan of the bones, QCT provides more detailed images than DEXA.
Ultrasound of the bones in the heel, leg, kneecap, or other areas.
While all of these can determine bone density and osteoporosis risk, "DEXA is the most important test and is the gold standard," says Felicia Cosman, MD, clinical director for the National Osteoporosis Foundation.