How often should a Dexa (Dual-Energy X-ray Absorptiometry) scan be performed?

DEXA Scan Frequency Guidelines

DEXA scans should be performed every 2 years for routine monitoring in most cases, with annual scans reserved only for high-risk individuals with conditions causing rapid bone loss. 1

General Population Recommendations

• Standard monitoring frequency: Every 2 years for routine bone density assessment 1
• Initial baseline scan: Recommended when clinical risk factors for osteoporosis are present 1

High-Risk Population Recommendations

For specific high-risk groups, more frequent monitoring is recommended:

Cancer Survivors

• Postmenopausal breast cancer survivors: Baseline DEXA scan followed by repeat scans every 2 years if on aromatase inhibitors 2
• Premenopausal women on tamoxifen and/or GnRH agonists: DEXA scans every 2 years 2
• Women with chemotherapy-induced premature menopause: DEXA scans every 2 years 2

Diabetes Patients

• Type 2 diabetes: DEXA scan at least 5 years after diagnosis, with reassessment every 2-3 years depending on additional risk factors 2
• Type 1 diabetes: Consider BMD assessment after age 50 2

Factors Warranting More Frequent Monitoring

More frequent monitoring (annually) may be appropriate for:

• Patients receiving glucocorticoid therapy for more than 3 months 1
• Patients initiating therapy with medications known to adversely affect bone mineral density 1
• Individuals with decreasing BMD despite treatment 1

Common Pitfalls to Avoid

1. Scanning too frequently: Performing DEXA scans more often than annually is not recommended as it may not show meaningful changes in BMD 1
2. Using different machines: Follow-up scans should be performed on the same DEXA machine to ensure accurate comparisons 1
3. Relying solely on T-scores: When comparing serial scans, absolute BMD values should be used rather than just T-scores 1
4. Ignoring risk factors: Failing to consider specific risk factors that might warrant more frequent monitoring can result in suboptimal care 1

Special Considerations

• For patients with normal BMD and minimal risk factors, scanning every 2-3 years is appropriate 1
• In patients with osteoporosis receiving treatment, monitoring is essential to assess treatment response 1
• After a fragility fracture, patients should be diagnosed with osteoporosis regardless of DEXA data and monitored accordingly 2

DEXA scanning remains the gold standard for bone mineral density assessment due to its low radiation dose, short scan times, high-resolution images, and good precision 3. While CT technology has shown correlation with DEXA measurements 4, DEXA continues to be the preferred method for diagnosing osteoporosis and monitoring treatment response.