Bone Densitometry (DEXA) Test – Frequently Asked Questions and Answers Bone densitometry, (also known as dual energy X-ray absorptiometry) is a test that uses a small dose of ionizing radiation to calculate bone density quickly and accurately. Bone densitometry test (also called dual energy X-ray absorptiometry/DXA or DEXA) is an advanced medical ultrasound imaging technique that calculates bone mineral content and density quickly and accurately. Primarily used to discover osteopenia or osteoporosis, the test uses a very small dose of ionizing radiation to capture images inside the body, normally the lower spine and hip, to measure bone loss. Osteoporosis is a bone disorder that causes weakening of the skeleton due to loss of bone minerals and calcium, which increases the possibility of fractures. In most cases, the bone density test is recommended after the age of 60 years. However, it can also be advised earlier in cases where reduced bone density is suspected. If you are planning to do DEXA scans in Queens, NY area, make sure to choose a reputable and certified medical imaging center that uses state-of-the-art technology to produce high-quality images. Here are some of the frequently asked questions and answers about bone densitometry scans. Q: What is a bone density measurement? A: A bone density measurement is a quantitative noninvasive test (like an X-ray) that quickly and accurately measures the mineral density of the bone or area measured. It is mainly used to detect osteopenia or osteoporosis, wherein the bone's mineral density is low and the risk of fractures are high. Q: What are some common uses of the procedure? A: Physicians recommend bone densitometry test to – *
Determine the risk of broken bones (fractures)
* Confirm a diagnosis of osteoporosis (gradual loss of calcium and structural changes, causing the bones to become thinner, more fragile and more likely to break) *
Monitor osteoporosis treatment
Q: How does the bone densitometry procedure work? A: A DXA scan measures bone mineral density (BMD) by using a thin, invisible beam of low-dose X-rays with two distinct energy peaks, which is passed through your bones. One peak is absorbed mainly by the soft tissue and the other by bone. The soft tissue amount is deducted from the total and what remains is – the patient’s total BMD. All devices feature special software to compute the data and display them on a monitor, thereby allowing the physician to make an accurate diagnosis.
Q: How much radiation will a patient be exposed to? A: Patients will be exposed to extremely small amount of radiation – less than one-tenth the dose of a standard chest x-ray. However, as with any specific diagnostic ultrasound imaging techniques, it is important to inform the physician in advance if you are pregnant. Q: What does the scanning equipment look like? A: DEXA equipment consists of a central device and a peripheral device. Central devices have a large, flat table and an “arm” suspended overhead, and measure the bone density in the spine and hip. A peripheral device on the other hand, is a portable box-like structure which measures bone density in the wrist, heel or finger. Q: Who should undergo BMD test? A: Physicians advise BMD test for the following people – *
Patients with osteoporosis, or are concerned about having osteoporosis
* Postmenopausal women below the age of 65 years who have one or more additional risk factors for osteoporosis *
Patients who are or have been undergoing hormone replacement therapy for long periods
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Women aged 65 years and older (regardless of additional risk factors, who sustain a fracture)
Q: How long does it take to complete a BMD test? A: The whole procedure will take about 10-20 minutes to complete, and this will again depend on how many regions are measured. Q: How to prepare for a bone density scan? A: As bone density tests are easy and painless, there is no special preparation required for the same. If you are doing the test at a medical center or a hospital, inform your physician in advance about contraindications which include – pregnancy, recent contrast CT (contrast material injected for a CT scan or nuclear medicine test) or radioisotope examination. The patient should avoid taking calcium supplements for at least 24 hours before the BMD test. Wear loose and comfortable clothing without zippers, belts or buttons. In addition, remove all metal objects such as keys or coins from dress pockets. Q: How is the bone densitometry procedure performed? A: The dexa bone densitometry procedure is generally performed on an outpatient basis. In the central DEXA scan (which measures bone density in the hip and spine), the patient lies on a padded table. An Xray generator is located below the patient and an imaging device or detector is positioned above. To
assess the spine, the patient’s legs are supported on a padded box to flatten the pelvis and lumbar spine. For the hip part, the patient’s foot is placed in a brace (that rotates the hip inwards). In both cases, the detector is slowly passed over the area, generating images on a computer monitor. On the other hand, the peripheral tests are quite simpler wherein the patient’s finger, hand, forearm or foot is positioned in a small device that captures a bone density reading within a few minutes. Patients must remain immobile and may sometimes be asked to keep from breathing for a few seconds (while the Xray images is taken) in order to reduce the possibility of a blurred image. Q: What happens after a DEXA scan? A: There is no special type of care required after undergoing a bone density scan. Generally, patients can resume their normal activities (unless your physician advises differently). In some cases, your physician may give you additional or alternate instructions after the procedure depending on your particular condition. The results of the scan can be obtained within 24 hours after the test. Osteoporosis is one of the most common skeletal disorders, (particularly among aged people) resulting in increased risk of future fracture. Measuring bone mineral density using DEXA scan has been widely accepted as a simple, quick and non-invasive procedure for the accurate diagnosis and management of osteoporosis. This in turn may reduce the incidence of fracture and improve the quality of life of people.
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