What is a DEXA scan?
DEXA stands for 'Dual Energy X-ray Absorptiometry'. It is a test
that measures the density of bones and, in general, the more dense
the bone, the stronger it is, and the less likely it is to
break.
A DEXA scan uses low energy X-rays. The more dense the bone is,
the fewer X-rays get through to the detector. By using two
different X-ray sources rather than one it greatly improves the
accuracy in measuring the bone density.
The amount of X-rays that comes through the bone from each of the
two X-ray sources is measured by a detector. This information is
sent to a computer which calculates a score of the average density
of the bone. A low score indicates that the bone is less dense than
it should be, some material of the bone has been lost, and is more
prone to fracture.
What does this involve?
A DEXA scan may be advised if you are at increased risk of
osteoporosis even though you may have no symptoms at
first. However, if you do have osteoporosis, you have an increased
risk of breaking a bone. If a DEXA scan shows that you have
osteoporosis, then you may be given advice and treatment to help
strengthen your bones. Therefore, a DEXA scan may be advised if you
have:
- A fracture following a minor fall or injury.
- Loss of height due to fracture of a vertebra (back bone).
- Taken steroid tablets for three months or more.
- An early menopause (aged less than 45).
- A history of periods stopping (amenorrhoea) for more than one
year before the menopause.
- Other disorders associated with osteoporosis such as rheumatoid
arthritis or coeliac disease.
- A family history of hip fracture on your mother's side.
- A body mass index of less than 19. (That is, if you are very
underweight.)
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When will I recover?
A DEXA scan can be done as an outpatient procedure and you can
go straight home afterwards.
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What risks should I know about?
Although x-rays are used for this scan, the
radiation dose is so low that the Radiographer can safely stay in
the room with you. The radiation exposure from a DEXA scan is very
small and is equivalent to less than 10% of one day's natural
radiation exposure from the atmosphere. However, if there is any
possibility that you may be pregnant, please inform the x-ray
department before you come for your appointment.
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Circle care
DEXA scanning is carried out by our specialist
radiographers in state of the art facilities where you can be sure
of the best possible care.
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