DEXA Scan to

Detect

Osteoporosis

DEXA scan

Information

Common questions

About DEXA scan

Who should have a DEXA scan?

Preparition for DEXA scan

What happens during a DEXA scan

Use in paediatrics

Interpretion

What are the risks?

What is DEXA Scanning? (About Dexa

Scan )

DEXA scan is an instrument

used to measure the density

of bones. DEXA stands for

dual energy X-ray

absorptiometry. It is now also called

DXA scan. Measurements of bone mineral density are important in many areas of science, but its most important use is found in clinical assessment of osteoporosis (which is a disease in which there is decreased bone mineral density, possibly due to menopause, malnutrition and various other factors).

Who should have a DEXA scan?

• estrogen deficiency in women at clinical risk for osteoporosis

• evidence of vertebral abnormalities

• long term steroid use

• patients with primary hyperparathyroidism

• the need for monitoring to assess response to approved drug therapies for osteoporosis.

• People with Gorhams vanishing bone disease / Lymphangiomatosis

About DEXA scan

Working of the DEXA Scan

In a DEXA scan, the patient is placed

between two sources of X-ray radiation

and a detector. The two sources of X-ray radiation emit

X-rays of different energy levels. These X-rays

penetrate the body depending on the density of the

body tissues i.e. denser tissues do not allow X-rays to

pass through. The X-rays transmitted out on the other

side are detected by an electronic detector, which then

calculates the density of the entire tissue region

between the X-ray source and the detector.

It also calculates the density of specific tissue such as bone by subtracting the other soft tissue absorption value from the source, and hence can gives a clear idea of the bone mineral density. Using two X-ray sources is simply

Preparition 0f DEXA scan

You probably won't need to make any preparations before scan. If the patient usually take medication, continue to take this as usual unless his/her doctor specifically tells no.

• It's best to wear light clothing that doesn't have metal fasteners over y spine or tummy areas. Remove any metal jewellery that wear in navel because this can interfere with the scan of spine.

• A radiographer (a health professional trained to perform imaging procedures) will operate the scanning equipment.

• A DEXA scan isn't recommended for pregnant women, unless there is an urgent medical reason. Please tell your radiographer if you could be pregnant.

Patient may be asked to sign a consent form. This confirms that he understand the benefits, risks and possible alternatives to the procedure and have given his permission for it to go ahead.

What happens during a DEXA scan

The scan usually takes about 10 minutes. Patient

may be asked to remove clothing and put on a

gown.

Patient will be taken to the X-ray room and asked

to lie down on an X-ray table. The radiographer

will operate the scanner from behind a window.

He or she will be able to see, hear and speak to

pt. during the procedure.

What happens during a DEXA

scan

The X-ray machine will slowly pass over your

body and send X-rays through the bones being

tested, usually the hip and lower spine.

A detector will measure how much X-ray radiation

passes through the bones and sends the

information to a computer. It can take as little as

10 seconds to scan each bone - it's important to

lie very still while this is happening.

Current practice in paediatrics

However, it seems that DXA is still in its early days in paediatrics, and there are widely acknowledged limitations and disadvantages with DXA.

Some clinics may routinely carry out DXA scans on paediatric patients with conditions such as nutritional rickets, lupus, and Turner Syndrome. DXA has been demonstrated to measure skeletal maturity and body fat composition and has been used to evaluate the effects of pharmaceutical therapy. It may also aid paediatricians in diagnosing and monitoring treatment of disorders of bone mass acquisition in childhood

How do you interpret the test

results and who is a candidate for

treatment?

• A DEXA scan report

compares the patient's bone

mineral density values with

those of young normal

patient (T score) and with

age matched normal patient

(Z score). By comparing a

patient's bone density

against there peers, a low

score indicates there may

be a reason other than age

related bone loss.

How do you interpret the test

results and who is a candidate for

treatment?

Patients risk factors for osteoporosis that should play a part in the decision to begin treatment include: a maternal history of a hip fracture, any previous fracture after the age of fifty, tall height at age of 25, poor health, some sedatives and anticonvulsant drugs, and the inability to rise from a chair without the use of the arms. The current treatment recommendations are the start of drug therapy to reduce the risk fracture for all women with a bone mineral density T score of less than -2 without other risk factors and for those with a T score of less than -

interpret ion of the test

results

• between 0 and -1 (for example, -0.5), your bone density is normal

• between -1 and -2.5, this is classed as osteopenia - this means bone density is lower than normal, but don't yet have osteoporosis

• below -2.5, this is classed as osteoporosis

• sometimes Z score be given in a scan. This is a measure of how the bone density compares to the average for a person of his own age. This score isn't used to diagnose osteoporosis, but can be used along with age and gender to calculate risk of having a hip fracture in the next 10 years.

What are the risks?

Radiation exposure

Less then the amount of radiation that one receives on an airline flight from Delhi to London and back.

There are a certain group of individuals who should not have the Dexa Scan test. These are

Women who are pregnant or who think they might could be pregnant

Anyone who has had another “contrast x-ray” within the last seven days (examples--upper GI test, CAT scans…)

Anyone who has had a nuclear scan within the last seven days (examples--bone scan, thyroid study…)

What are the risks & benifits

The dexa scan is used to measure bone mineral density as opposed to a regular x-ray or CAT scan for a variety of reasons. First, the dexa scan is extremely accurate; even more so than an x-ray. For bone density loss to show up on a regular x-ray, a person would have to lose 20-30% of their bone mass. Second, the dexa scan requires much less radiation exposure than a CAT scan or “regular” x-ray (Radiographic Absorptiometry). Ironically and interestingly, a person is exposed to more radiation on a “coast-to-coast” airline flight than during a dexascan! Lastly, dexa scans are much less costly than other tests. The current cost (January 2009) for a dexa scan is around Rs.1000/-for W.B. & 400/- for single site,in Govt. institute, it might be worth your while to have this test if your doctor advises it or you are in one of the risk groups listed above.

DEXA SCANNING FANTASTIC

FOR MEASURING B M D

The dexa scan is a fantastic

test for measuring bone

mineral density&body fat

compositin. It is

affordable, painless and

extremely accurate. Most

definitely this is a test worthy of

your time in relation to

osteoporosis diagnosis and

treatment.

PROTECTION IS

ESSENTIAL