Dexa Scan Bone Density

Submitted by Medical Health Test Team on October 17, 2012

A DEXA scan is an X-ray based test to measure the bone density of an individual. The full form of the name is the Dual Energy X-ray Absorptiometry test. The bones form an integral part of the body and their good health is essential for a person to live a normal life. The bones are important for body structure, rigidity and movement. Human bone is made up of mineralized tissue. This tissue forms a sort of honeycomb shaped web within the bone that makes it strong while retaining the lightness that is required for easy movement. This is an extremely efficient design but it does have its limitations. The density of the mineral structure of the bone is important. If this density falls below a certain amount, then the person is likely to suffer from the effects of weakened bones.

Osteoporosis is a condition that causes bone density reduction. A reduction can occur due to other conditions as well, including cancer. Cancer itself cannot be tested by using a DEXA scan but the effects of the cancer on the bone density could be measured using the DEXA scan for bone density. A DEXA scan for bone density can be conducted using a specialized X-ray machine. This machine fires two different beams at the bones of the body. One beam is weaker while the other is stronger. The response of the bones to each beam and the amount of absorption of the beam energy that takes place is used to measure the density of the mineral structure being measured. A DEXA scan for bone density takes just a few minutes and can be conducted without any prior preparation. It is important to note that the DEXA scan is different from the traditional bone scan which uses a radioactive isotope and is used for other diagnostic applications.

The results of the DEXA scan are represented in the form of a test score. The score is a result of the calculation of the machine and the criteria used to judge the patient. There are two forms of criteria used. For a T-score, there is only one criteria and that is the patient's gender. The more comprehensive Z-score uses factors such as the patient's age, gender, ethnic heritage and body weight as factors by which the test results are compared. The Z-score is more likely to provide an accurate result than the T-score because of the various extra factors that are taken into consideration.

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