Frequently Asked Questions Regarding DEXA
What is a DEXA scan?
A DEXA scan is a low dose x-ray that checks for signs of mineral loss and bone thinning. The x-rayed areas are usually the spine, the hip and the wrist. A DEXA scan delivers a minute amount of radiation. It is a simple painless procedure which takes about 15 minutes.
When should a woman have a DEXA scan?
For women, the best time to have a DEXA scan is around menopause when the estrogen production in your body starts to decline and you become susceptible for bone loss and fractures. It is also a good time to establish a baseline measurement for future comparison.
How should I prepare for the DEXA scan?
You will be asked to wear a comfortable two piece outfit or you may put on a gown. You must not wear any metal buttons, buckles or zippers, as these materials may interfere with your results.
What happens during the DEXA scan procedure?
You will be asked to lie down on your back and side on the exam table. An overhead scanner will travel above your body and take readings of the bone density. Please lie still during the exam so that the pictures are clear.
How long does the DEXA scan procedure take?
The DEXA scan exam will take about 15 minutes.
When will I know the results?
Once the exam is completed, a computerized print-out will be analyzed by the radiologist. The radiologist will then send your doctor a written report. You should contact your physician within two days of your exam to make an appointment to go over your results and discuss your next step.
What is a bone density measurement?
A bone density measurement provides a way to quantify your bone mineral density. It is mainly used to detect osteopenia or osteoporosis, wherein the bone’s mineral density is low and the risk of fractures are high.
What are some common uses of the procedure?
Physicians may recommend DEXA to:
- Determine the risk of developing fractures (broken bones)
- 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
How does the bone densitometry procedure work?
A DEXA 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.
How much radiation will a patient be exposed to?
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 imaging techniques, it is important to inform the physician in advance if you are pregnant.
What does the scanning equipment look like?
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.
Who should undergo BMD test?
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
- Women aged 65 years and older (regardless of additional risk factors, who sustain a fracture)
How long does it take to complete a BMD test?
The whole procedure will take about 10–20 minutes to complete, and this will again depend on how many regions are measured.
How to prepare for a bone density scan?
As bone density tests are easy and painless, there is no special preparation required for the same. 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.
How is the bone densitometry procedure performed?
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 X-ray 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 X-ray images is taken) in order to reduce the possibility of a blurred image.