A DEXA Bone density scan is a test to measure bone mineral concentration which is a measure of bone strength. DEXA scanning may be used for baseline measurement , fracture risk assessment, follow up from a previous scan, and to measure change following therapy and / or life style change .

Osteoporosis
Bone density increases in the average person until around age 30 years. The bone density may plateau or bone loss starts to occur at around 1% per year. There is continuous turnover of bone mineral content by both osteoclastic and osteoblastic activity. Osteoporosis results from an imbalance between these processes, either through accelerated bone loss or insufficent bone formation. Accelerated bone loss may occur for a number of lifestyle or physical reasons and 'risk factors'.
For women, the decrease in oestrogen production at menopause results in bone loss. For some women this may be rapid and severe because women generally have smaller, thinner skeletons than men; and because women go through menopause. Other factors such as dietary deficiency, lack of exercise, smoking and alcohol contribute to bone fragility in both sexes.

A DEXA scan can:

• detect low bone density before a fracture occurs
• predict any increased risk of fracture
• confirm a diagnosis of osteoporosis
• determine rate of bone loss, with serial studies
• monitor the effect of treatment for osteoporosis

Risk factors
Risk factors are helpful when identifying people more likely to develop osteoporosis, Risk factors that increase the chances of developing osteoporosis are:

• being female
• a small slender body habitus
• advanced age
• a family history of osteoporosis
• early menopause
• abnormal absence of periods (amenorrhea)
• anorexia nervosa or bulimia
• a diet low in calcium
• use of certain medications, (eg. Steroids, anticonvulsants, thyroxine)
• low testosterone levels in men
• a sedentary lifestyle
• cigarette smoking
• excessive alcohol intake
• malabsorption problem

			Pre Examination
	An appointment is required. Patients may be referred by a Medical Practitioner or self refer. Self referring patients will be advised to send a copy of their report to their Doctor.

			The Examination
	Patients will be asked to complete a short questionnaire and provide give weight and height. The Patient lies on a table and a ‘C arm' scanner moves over not touching the patient.  The patient does not need to undress if they wear loose fit clothing without large buckles, metallic buttons and zips. The scan takes about 20-30 minutes. Most commonly the areas scanned are hip and lower spine although wrist and whole body scans are also performed for some indications.

			Post Examination
	A Radiologist or Osteoporosis Specialist will report on the images giving T and Z scores for scanned areas. The report will provide risk assessments compared to age. A paper copy of the images and report are sent to your patient.