Health Care Imaging

Bone Density (DEXA) Scan

What is Osteoporosis?

Osteoporosis is a condition characterised by low bone density. Low bone density makes bones fragile, brittle and more susceptible to fractures. In patients with osteoporosis, a minor fall can cause a major injury which is why early detection and treatment of this condition is important. Bone densitometry is a specialised, low-dose x-ray procedure used to measure bone density. Osteopaenia is the intermediate stage of bone weakening which, if left untreated, may lead to osteoporosis.

What is Bone Density Test?

A bone density test, also known as a DEXA scan, is the single most useful method in the diagnosis of Osteoporosis and evaluating the risk of fracture. The scan is a fast (20 minutes), safe and painless diagnostic test that reveals how strong the bones are and can help referring doctors make decisions about the types of treatments options that are the most appropriate for the patient. A Bone Density test can also be used to predict the response to treatment for osteopaenia and osteoporosis.

The Bone Density Scan

There are two items of equipment in the bone densitometry room; the table with the x-ray machine and the computer system. The table has a padded top for comfort. The bone densitometry scanner produces a narrow x-ray beam which cannot be seen or felt, that passes from the x-ray source in the table through the patient, to the detectors in the scanner arm above the patient. The operator, a trained BMD technologist, sits at the computer console during the scan. Each region scanned takes between 3 to 5 minutes to complete. There is no preparation required for Bone Density testing.

Is the scan harmful?

The total radiation dose received in a bone density test is less than one-tenth of that emitted during a chest x-ray. It is thus considered to be a safe and non-invasive procedure.

Who interprets the results?

Once the test is complete, the technologist will give the results to the imaging specialist (Radiologist or Nuclear Medicine Physician) for interpretation. The imaging specialist analyses the images and measurements from the examination and a signed report with his/her interpretation is sent to the referring practitioner. The scans may be given to the patient on the day and results are usually ready within 24 hours.

What should a patient tell the technologist before a Bone Density test?

The technologist should be informed if the patient is pregnant or if they think they may be pregnant.

The technologist will also need to know if any barium examinations, contrast injections or radioisotope tests have been performed recently. If so, the scan should not be performed for 10-14 days after this.

What should the patient bring to a Bone Density test?

The patient should bring the referral from their Doctor, Medicare card and any previous bone density scans and results. The patient should also bring a list of current medications, if any.

What clothing should be worn for a Bone Density test?

Wear loose comfortable clothing free of zippers, belt and buttons made of metal. In the case where zippers or metal buttons are unavoidable, the patient will be given a gown to be worn during the examination.

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