DEXA Cheat Sheet 2026

The 30 highest-yield DEXA facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. ISCD guidelines recommend that a minimum of how many lumbar vertebrae must be analyzable for a valid spine BMD result? → Two
2. When conducting a risk assessment for DEXA operations, which factor should receive the HIGHEST priority? → Probability and severity of potential harm
3. A DEXA technologist calculates an in-vivo spine precision of 1.8% RMS-CV. What is the least significant change (LSC) at 95% confidence? → ~5.0%
4. What is the recommended minimum number of repeat scans used to calculate an in-vivo precision assessment for a DEXA technologist? → 30 patients scanned twice or 15 patients scanned three times
5. The Haversian canal system (osteon) is a structural unit found primarily in which type of bone? → Cortical (compact) bone
6. Which DEXA QA action should be performed if the daily phantom scan image shows unusual artifacts or distortion? → Halt patient scanning, document findings, and contact the service engineer
7. In bone remodeling, what is the correct sequence of events? → Quiescence → Activation → Resorption → Reversal → Formation
8. Which statistical tool is typically used to track DEXA daily phantom data over time and identify trends? → Shewhart control chart (QC chart)
9. How should the technologist handle a patient who has received an oral contrast agent (barium) within the last 7 days before a DXA scan? → Reschedule the scan until contrast has cleared the GI tract
10. When comparing DXA body composition results across serial scans, the technologist should ensure: → The same DXA system and software version are used for each scan
11. What is precision in DEXA scanning? → Reproducibility of results
12. In DEXA Bone Density Scan Certification, what is the PRIMARY purpose of conducting an initial assessment? → To establish a baseline and identify needs for appropriate action
13. What should patients remove before a DEXA scan? → All metal objects
14. What is the function of osteoclasts? → Bone resorption
15. When performing a lumbar spine DXA scan, which vertebrae are typically included in the standard analysis region? → L1 through L4
16. Which lab values are most important to review before initiating bisphosphonate therapy in a patient with low bone density? → Serum creatinine/eGFR (renal function) and 25-hydroxyvitamin D
17. In DEXA Bone Density Scan Certification practice, what is the CORRECT sequence when performing a technical procedure? → Plan, prepare, execute, verify, and document
18. What is the primary reason for using a foam positioning block between the patient's knees during a hip DXA scan? → To maintain consistent internal rotation and abduction of the femur
19. Bone tissue that is rapidly deposited during fracture healing or in Paget's disease, characterized by disorganized collagen fibers, is called: → Woven (fiber) bone
20. Which regulatory body sets the annual occupational radiation dose limit of 50 mSv for radiation workers in the United States? → NRC
21. How long should a DEXA technologist wait before performing a follow-up BMD scan to assess treatment response for a patient on bisphosphonate therapy? → At least 1–2 years after initiating therapy
22. The EWGSOP2 (European Working Group on Sarcopenia in Older People) recommends which DXA-based cutoff for low appendicular lean mass index (ALM/ht²) in men? → Less than 7.0 kg/m²
23. In a serial DEXA report, the phrase 'statistically significant decrease in BMD' should only be used when: → The BMD change exceeds the facility-specific Least Significant Change (LSC)
24. In DEXA Bone Density Scan Certification practice, what is the CORRECT sequence when performing a technical procedure? → Plan, prepare, execute, verify, and document
25. Which type of collagen predominates in bone extracellular matrix and provides tensile strength? → Type I collagen
26. What does a T-score represent? → Comparison to young adult average
27. In DEXA Bone Density Scan Certification, what is the PRIMARY purpose of conducting regular safety drills and exercises? → To ensure personnel can respond effectively in emergencies
28. Why must patients be asked about recent oral contrast or CT contrast agents before a DEXA scan? → Residual contrast can artificially alter BMD measurements
29. Which class of medications is most commonly prescribed as first-line pharmacotherapy for postmenopausal osteoporosis in the US? → Bisphosphonates (e.g., alendronate, risedronate)
30. A patient received a nuclear medicine bone scan 24 hours ago. How does this affect their DEXA appointment? → Postpone DEXA for at least 72 hours to allow radiopharmaceutical decay