10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The CBDT exam has 150 questions and runs 3 hours 30 minutes.
These 10 free CBDT questions are organized by exam domain, so you can see how each part of the Certified Bone Densitometry Technologist blueprint is tested. Reveal the answer and explanation under each question.
A 44-year-old man undergoes his first DXA during an evaluation for hypogonadism. He has no fragility-fracture history. His lumbar T-score is -2.3 and his Z-score is -1.6. Under ISCD reporting conventions, how should his BMD be described?
Correct answer: A - Within the expected range for age.
An untreated 67-year-old postmenopausal woman in the United States has valid T-scores of -1.8 at the femoral neck, -1.5 at the total hip, and -1.2 at the lumbar spine. She has no prior fragility fracture. Her correctly calculated 10-year FRAX probabilities are 3.8% for hip fracture and 14% for major osteoporotic fracture. Which statement correctly separates her densitometric classification from the BHOF treatment criteria?
Correct answer: D - She has low bone mass, and the hip probability supports considering pharmacotherapy.
At a follow-up DXA appointment, a woman receiving denosumab asks whether she can take a medication holiday now that her T-score has improved. Which drug-action and discontinuation pairing explains why this requires a specific plan from her prescriber?
Correct answer: D - RANKL blockade; an unplanned interruption can trigger rebound resorption and multiple vertebral fractures.
After a technologist declares her pregnancy, the radiation safety officer reviews her workload, workstation, and dosimetry. The review confirms that all applicable declared-pregnancy requirements can be met without reassignment. Which work arrangement is justified?
Correct answer: B - Continue scanning with the reviewed controls and assigned monitoring.
Two technically comparable total-hip studies on the same scanner show BMD increasing from 0.780 to 0.805 g/cm². The facility's in-vivo precision error at this site is an RMS-SD of 0.012 g/cm²; repeated phantom scans have an SD of 0.002 g/cm². Which conclusion uses the appropriate 95% least significant change (LSC)?
Correct answer: A - No significant change; the applicable patient LSC is approximately 0.033 g/cm².
Before a detector replacement, phantom BMD clustered around 1.000 g/cm². With the same phantom and verified positioning, the next five checks are 1.023, 1.024, 1.023, 1.025, and 1.024 g/cm². The approved action limits remain 0.985-1.015 g/cm². What does this pattern demonstrate?
Correct answer: A - Repeatability is preserved, but post-service calibration is outside the approved action limits.
The foot is secured in the positioning device for a left hip DXA, yet the image shows a prominent lesser trochanter and a foreshortened femoral neck. The patient has no hip pain or movement restrictions. Which correction addresses the acquisition error?
Correct answer: C - Increase internal rotation of the femur and reacquire the hip.
The referral documents primary hyperparathyroidism in a 59-year-old woman. Her PA spine and hip scans are technically valid, with T-scores of -0.6 and -0.8. Neither forearm has a prior fracture or hardware. An additional measurement is still indicated at which site?
Correct answer: D - The nondominant 33% radius, emphasizing a predominantly cortical site.
Four patients are being considered for vertebral fracture assessment. All listed T-scores are from valid diagnostic sites; none reports a prior vertebral fracture or has additional risk factors beyond those stated. Under the ISCD VFA indications, which patient qualifies?
Correct answer: B - A 66-year-old woman with T-score -1.6, historical height loss of 5 cm, and no glucocorticoid use.
Review of a PA lumbar scan confirms correct vertebral labeling and marked focal degenerative sclerosis at L3. The other levels are technically evaluable. Individual T-scores are L1 -2.4, L2 -2.2, L3 -0.4, and L4 -2.3. Which vertebrae should contribute to the reported lumbar BMD?
Correct answer: C - L1, L2, and L4; retain the unaffected levels.
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