The DXA: Dual-energy X-ray absorptiometry is a bone mineral density (BMD) analyzer including trabecular bone score (TBS) used to assess the risk of osteoporosis. The DXA is also capable of analyzing various components in the body, including fat mass, muscle mass, osteoporosis, and the average bone mass of the whole body. The DXA is considered as a test that has been accepted all over the world since it is highly accurate and can be easily and quickly examined by using very small radiation doses.
The elements that can be detected by the DXA are as follows.
- Lumbar spine, a test for bone mineral density and quality within the lumbar spine
- Femur, thigh bone density determination test
- VFA (vertebral fracture assessment), to check whether there is any fracture or collapse of the dorsal vertebra
- Body composition, a measurement of body fat, muscle mass and the average bone mass of the whole body
The main functions of the DXA SCAN machine
- Bone density analysis (BMD) is generally performed on the lumbar spine and femur. It may also be examined at the wrist bone (forearm) in some patients who have abnormal high levels of parathyroid hormone (Hyperparathyroidism). Bone density analysis is also used in patients who cannot examine the lumbar spine or thighs. It is also an option for the patients with overweight who a bed cannot bear. The analysis includes a structural examination of the lumbar spine (TBS) to assess the risk of developing osteoporosis and 10-year risk of fracture due to osteoporosis.
- Analyze various components within the body, including fat mass, muscle mass and mean total bone mass which the machine are able to analyze.
- a. The amount of fat stored in the body: The DXA SCAN machine can tell both the quantity and the percentage when compared with muscle mass and bone. It is able to analyze the distribution of fat in any part such as fat accumulation in the limbs, torso or hips which may be more important than the amount of body fat. It is found that having more visceral fat in the abdomen has a higher risk of developing cardiovascular disease, high blood pressure, insulin-resistant diabetes, high blood lipid levels, fatty liver, etc.
- b. Muscle mass in the body: The machine can analyze total muscle mass and distinguish muscle mass in different parts of the body, such as muscle mass in the limbs and trunk. Decreased muscle mass in the elderly may cause unhealthy overall health and lead to easily fall. People with illness also have a higher risk of complications or side effects from the drug than people with normal muscle mass. It will also be useful in people who want to lose weight. Wrongly losing weight may result in decreased muscle mass which is more of a disadvantage. The DXA SCAN machine is an alternative for athletes and body builder who want to create muscle data in different parts of the body. The machine will help you plan your exercise.
In addition, information on the various components within the body, including fat and muscle will help in nutritional planning, both in patients who need to lose weight and patients who have problems with intestinal function (Malabsorption). The data also allows for optimal dose adjustment in cancer patients, HIV-associated lipodystrophy testing and in patients who have to do physical therapy. The information will help to adjust a more appropriate treatment plan.
Preparation before the examination
- For Bone Mineral Density (BMD) examination
- No need to abstain from water and food.
- The examination takes about 15-20 minutes.
- For checking Body Composition
- Abstain from food for at least 4 hours, but can drink plain water.
- Abstain from alcoholic beverages for at least 48 hours.
- Do not exercise 12 hours before the examination.
- The examination takes about 20-30 minutes.
- The examination should be postponed in case of previously undergoing a barium study over one week, or having had a contrast agent or a nuclear medicine examination in a period of 1-2 days
- Not recommended for pregnant women. Although this test has a small amount of radiation, the examination should be postponed first if you suspect of pregnancy.
Examination procedure
Change into the uniform provided by the hospital and take of a bra.You are advised to go to a toilet before being examined. After that, the staff will place the patient on the bed in proper posture. While examining, stay still, do not moving but able to breathe normally.
