Region 05 · Preparationbodycomposition.com.au
Before a DXA scan
For a bone density scan, healthdirect says you will need your doctor or specialist to refer you. Victoria’s Better Health Channel adds that several things need talking through with your doctor first, among them whether you are pregnant: it says pregnant women should not have bone density testing.
- Referral
- From your doctor or specialist, for a bone density scan
- Medicare
- Sometimes covers a DEXA bone density scan
- Results
- Sent to your doctor
General information Not medical advice. Call Triple Zero (000) in an emergency, or go to the emergency department of your nearest hospital. For health information, see healthdirect; for radiation safety, see ARPANSA: Code for Radiation Protection in Medical Exposure (RPS C-5).
Method
Why bone density is tested with DXA
Victoria’s Better Health Channel calls DEXA the most popular technique for bone density testing, because it is fast and highly accurate, and says the testing can identify osteoporosis or a milder form of bone loss, osteopaenia. It also says ordinary x-rays can only detect osteoporosis once around a third of bone mass has gone.
Sequence
Five steps, from referral to result
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Referral
Your doctor might refer you for a bone density scan when you have a risk of osteoporosis, healthdirect says. It names males over 60 and females over 50 as having a higher chance of osteoporosis when they also have one or more factors from a list. It lists these factors:
- a family history of a fragility fracture
- smoking, or drinking alcohol above healthy levels
- a vitamin D or calcium deficiency
- low body weight
- recurrent falls
- being immobile (unable to walk or do housework without help) or doing little physical activity
- long-term corticosteroid treatment, or some other medicines taken long term.
healthdirect adds that some medical conditions can also raise the risk of osteoporosis, such as early menopause, endocrine (hormone) disorders, anorexia nervosa, diabetes and HIV. Victoria’s Better Health Channel says osteoporosis is common in the elderly, particularly females, and that some diseases and conditions can add to bone loss, among them hormonal (endocrine) disease, rheumatoid arthritis, chronic liver disease and chronic kidney (renal) failure. It lists the situations in which bone density testing is most often used:
- having osteoporosis, or being postmenopausal and worried about it
- a deformity of the spine (vertebral deformity)
- osteopaenia, meaning decreased bone density
- a fracture in the past.
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Medicare
Medicare sometimes covers the cost of a DEXA bone density scan, healthdirect says. MBS Online’s 2017 fact sheet on the bone densitometry items described two new time-restricted items, from 1 November 2017, for people aged 70 or over. A patient aged 70 or over who has not had the service before is eligible for an initial scan under item 12320. Repeat testing then depends on the T-score:
Repeat testing under the items for people aged 70 or over, from MBS Online’s fact sheet. Check MBS Online for the current items before relying on them. Bone mineral density T-score Repeat testing −1.5 or above Every five years Less than −1.5 and above −2.5 Every two years Patients diagnosed with osteoporosis continue to be tested under other clinically appropriate MBS bone densitometry items, the fact sheet says.
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Talking it through
The Better Health Channel says there are several things to talk through with your doctor before the test. Its list includes:
- your medical history
- your risk factors for bone disease
- whether you are pregnant: the page says pregnant women should not have bone density testing
- any special instructions to follow beforehand.
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The day
Usually you change into a hospital gown, and all jewellery comes off before the test, the Better Health Channel says. The test does not hurt, healthdirect says, and you may not feel anything at all. It usually measures bone density in the lower back and the hip, and sometimes the forearm.
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Results
You can go home straight away, the Better Health Channel says, and you will need a follow-up appointment with your doctor to discuss your results. healthdirect says the results are sent to your doctor. What a scan measures explains how a T-score is read. If repeat tests are needed, as they may be for someone with osteoporosis, the Better Health Channel suggests having them all at the same testing facility, on the same machine.
Body composition
A scan for body composition alone
Radiation note
ARPANSA’s Radiation Health Committee says that a DXA scan done only to find body fat and lean tissue, with no clinical indication behind it, does not justify the radiation, because it brings no net benefit. Other ways of measuring lean body mass that use no ionising radiation are available, it says. For children, it says, extra attention to technique is needed to avoid an increased dose.
ARPANSA’s 2016 statement said DXA as a medical procedure was regulated by its code RPS14, which required appropriate referral, justification and approval by appropriately qualified medical practitioners. ARPANSA has since superseded RPS14 with its Code for Radiation Protection in Medical Exposure (RPS C-5, 2019), together with RPS C-1. In Victoria, management licence holders must comply with the department’s requirements for assessing body composition with DXA (condition M1758). DXA and radiation and Who may run a DXA scan set out both.