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What is DEXA Scanning?
Dual Energy X-ray Absortiometry
DEXA scanning is the most popular method to measure bone mineral
density and is primarily used for early detection of osteoporosis
and potential
fractures.
DEXA scanning studies have shown that individuals with osteoporosis
have
substantially lower bone density measurements than normal, age-matched
people. Bone mineral density is widely accepted as a good indicator
of bone
strength. Thus low values can be compared against standard bone
density
measurements and help predict a patient's risk for fracture based
upon the
DEXA scan measurements.
What is Osteoporosis?
Osteoporosis is a disease that reduces bone density creating porous,
fragile
bones. More than half of all women over 60 suffer from osteoporotic
fractures. Osteporosis is often first detected when the fracture
actually
occurs. Detected in time, osteoporosis is treatable.
What causes Osteoporosis?
Bone is living tissue that continually breaks down and reforms.
During growth, bone forms faster than it breaks down till it reaches
a peak bone mass between the ages of 25 and 35. After age 35, both
men and women lose bone mass at a greater rate than it forms, causing
bone loss. After menopause, women start to lose bone at a much more
rapid rate than men of the same age. This rapid bone loss is usually
due to the decrease in the production of the estrogen hormone. As
a great amount of the bone mass is lost, the bones become porous
and brittle, and thus break easily.
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What are the Benefits of DEXA Scanning?
DEXA scanning is the most widely used method for measuring bone
mineral
density for several reasons. When compared with radiographic absortiometry
or single energy x-ray absortiometry, DEXA scanning more precisely
documents
small changes in bone mass and is more flexible since it can be
used to
examine both the spine and the extremities. A scan of the spine,
hip or the
total body requires only one, two or four minutes respectively.
Qualitative
computed tomography (QCT) is the only technique that can directly
measure
bone density and volume but can distinguish trabecular from cortical
bone.
DEXA scanning is less expensive, exposes the patient to less radiation
and
is more sensitive and accurate at measuring subtle changes in bone
density
over time or in response to drug therapy than is QCT.
Any special precautions?
Pregnant patients should consult their doctor for advice before
scheduling a scan.
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