bone densitometry

Bone density scanning, also called dual-energy x-ray absorptiometry (DXA) or bone densitometry, is an enhanced form of x-ray technology that is used to measure bone loss. Bone density studies are today’s established standard for measuring bone mineral density.

Bone densitometry is most often used to diagnose osteoporosis, a condition that often affects women after menopause but may also be found in men and rarely in children. Osteoporosis involves a gradual loss of calcium, as well as structural changes, causing the bones to become thinner, more fragile and more likely to break.

Bone densitometry is effective in tracking the effects of treatment for osteoporosis and other conditions that cause bone loss. Bone density testing can assess an individual’s risk of developing fractures. The risk of fracture is affected by age, body weight, history of prior fracture, family history of osteoporotic fractures and life-style issues such as cigarette smoking and excessive alcohol consumption. These factors are taken into consideration when deciding if a patient needs therapy.

Bone density testing is strongly recommended for the following risk factors:

  • Post-menopausal women who are not taking estrogen
  • Personal or maternal history of hip fracture or smoking 
  • Men with clinical conditions associate with bone loss
  • Use of medications that are known to cause bone loss, including corticosteroids such a Prednisone, various anti-seizure medications such as Dilantin and certain barbiturates, or high-dose thyroid replacement drugs
  • Type 1 (formerly called juvenile or insulin-dependent) diabetes, liver disease, kidney disease or a family history of osteoporosis
  • High bone turnover, which shows up in the form of excessive collagen in urine samples
  • Thyroid conditions such as hyperthyroidism
  • Parathyroid conditions such as hyper-parathyroidism
  • Experienced a fracture after only mild trauma
  • X-ray evidence of vertebral fracture or other signs of osteoporosis

Preparation for the study:

On the day of the exam you may eat normally. You should not take calcium supplements for at least 24 hours before your exam. You should wear loose, comfortable clothing avoiding garments that have zippers, belts or buttons made of metal. You may be asked to remove some or all of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, removable dental appliances, eye glasses and any metal objects or clothing that might interfere with the x-ray images. Inform your physician if you recently had a barium examination or have been injected with contrast material for a CT scan or radioisotope scan. You may have to wait 10 to 14 days before undergoing a bone density test.

Women should always inform their physician and x-ray technologist if there is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy so as not to expose the fetus to radiation. X-ray is necessary, precautions will be taken to minimize radiation exposure to the baby.