Bone densitometry (DEXA) (dual-energy-x-ray-absorptiometry)
is an enhanced form of x-ray technology that is used
to measure bone loss. DEXA is used to diagnose osteoporosis,
a condition that more often affects women after menopause
but may also be found in men. Osteoporosis involves
a gradual loss of calcium, causing the bones to become
thinner, more fragile and more likely to break. A DEXA
test can be used to assess a patient’s risk for
developing fractures, and determine if preventative
treatment is needed.
An X-ray is a painless medical test that helps physicians
diagnose and treat medical conditions. Involves exposing
a part of the body to a small dose of ionizing radiation
to produce pictures of the inside of the body. This
procedure is most often performed on the lower spine
and hips.
Bone Density testing is strongly recommended if you:
Post-menopausal woman and not taking estrogen.
Have a personal or maternal history of hip fracture
or smoking.
Are a post-menopausal woman who is tall (over 5 feet
7 inches) or thin (less than 70 kg).
Are a man with clinical conditions associated with bone
loss.
Use medications that are known to cause bone loss, including
corticosteroids such as Prednisone, various anti-seizure
medications such as Dilantin and certain barbiturates,
or high-dose thyroid replacement drugs.
Have type 1 (formerly called juvenile or insulin-dependent)
diabetes, liver disease, kidney disease or a family
history of osteoporosis.
Have high bone turnover, which shows up in the form
of excessive collagen in urine samples.
Have a thyroid condition, such as hyperthyroidism.
Have experienced a fracture after only mild trauma.
Have had x-ray evidence of vertebral fracture or other
signs of osteoporosis.
Preparation for procedure
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, 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 a contrast material for a
computed tomography (CT) scan or radioisotope scan.
You may have to wait 10 to 14 days before undergoing
a DEXA test.
Women should always inform their physician or x-ray
technologist if there is any possibility that they are
pregnant. Many imaging tests are not performed during
pregnancy because radiation can be harmful to the fetus.
If an x-ray is necessary, precautions will be taken
to minimize radiation exposure to the baby.
How long does the exam take?
The DEXA examination takes about thirty minutes. The
patient rests, without moving. This exam emits a very
small amount of radiation, with two different energy
levels to assess the differences of the bone density.
What Should I wear?
You should wear comfortable lightweight clothing, you
may be asked to change into a patient gown.
What are my risks for developing osteoporosis?
The typical risk factors include:
family history
female
Caucasian race
poor calcium intake
poor dietary vitamin D intake
low estrogen levels
small or thin body build
lack of activity
|