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ARRT Bone Densitometry Examination Practice Test

Bone densitometry practice centers on DXA acquisition and interpretation, with attention to how positioning, scan-field contents, and measurement conditions affect bone mineral density results. The question bank samples decisions involving artifacts, implants, patient motion, and alternative skeletal sites, as well as the technical safeguards needed to produce interpretable measurements.

Exam overview

Exam providerAmerican Registry of Radiologic Technologists
Exam codeBD
CategoryRadiologic Technology

About the ARRT Bone Densitometry Examination Exam

Relevant work includes assessing whether anatomy and positioning permit a reliable measurement, recognizing when metal or other artifacts may distort analysis, and responding appropriately when a patient cannot remain still. Questions also sample interpretation of DXA concepts such as bone mineral apparent density (BMAD), including its use to account for bone size in pediatric assessment. Quality practice involves limiting the scan field to the required anatomy, maintaining consistent measurement conditions, and using routine phantom scans to monitor system performance. For longitudinal comparisons, technologists need to understand why the same scanner is preferred and why cross-calibration matters when equipment changes. The bank also includes workflow decisions such as handling unsaved examination data and selecting a site when standard spine or hip measurements are not usable.

Sample Practice Questions

Review a selection from this exam's published US Practice Tests practice bank.

Question 1

A DXA image includes a region with a surgical implant near the measurement area. What is the most appropriate general approach to analysis?

  1. ARecognize that the implant may distort local measurements and follow applicable analysis guidance for the affected region
  2. BInclude the implant because it is part of the patient's anatomy
  3. CAssume the implant always lowers the reported BMD
  4. DCopy the region boundaries from an unrelated prior examination
Show answerCorrect answer: A

Metal implants can alter X-ray attenuation and compromise measurements in the affected region. The image should be assessed under applicable system and facility guidance; an affected region may not be suitable for valid analysis.

Question 2

A patient is unable to remain still because of severe pain during a DXA examination. What is the most appropriate initial action?

  1. AContinue scanning without documenting the limitation
  2. BPause and address comfort and safe positioning before proceeding, when feasible
  3. CAsk the patient to hold an uncomfortable position for the entire examination
  4. DIncrease scan speed without considering image quality
Show answerCorrect answer: B

Comfort and safe positioning support cooperation and reduce motion-related image problems. The technologist should pause, assess what adjustment is feasible, and follow local procedures rather than forcing a painful position or ignoring the limitation.

Question 3

What does a DXA bone mineral apparent density (BMAD) calculation attempt to address, particularly in children?

  1. AThe influence of bone size on areal BMD measurements
  2. BThe patient's radiation dose from the scan
  3. CThe difference between cortical and trabecular bone at the forearm
  4. DThe amount of calcium consumed in the previous day
Show answerCorrect answer: A

DXA reports areal BMD, which can be influenced by bone size. BMAD is an approach that estimates volumetric density and can help account for size-related effects, an important consideration in pediatric assessment.

Question 4

Which skeletal site is commonly used for DXA assessment when the lumbar spine and hip cannot be measured or interpreted reliably?

  1. ADistal radius of the nondominant forearm
  2. BMidshaft of the tibia
  3. CCalcaneus of the dominant foot
  4. DClavicle
Show answerCorrect answer: A

The 33% (one-third) radius of the nondominant forearm is a recognized DXA measurement site when standard spine or hip sites are unavailable or unsuitable. Other peripheral sites are not interchangeable with this standard forearm region for diagnostic classification.

Question 5

Why should serial DXA scans ideally be performed on the same scanner or on scanners with a documented cross-calibration?

  1. ATo ensure that observed differences can be distinguished from measurement-system differences
  2. BTo eliminate the need for patient positioning
  3. CTo make every patient's reference database identical
  4. DTo guarantee that BMD will remain unchanged between scans
Show answerCorrect answer: A

Different systems may produce systematically different measurements. Using the same scanner, or applying appropriate cross-calibration and quality-control procedures, supports valid comparison of change over time.

Question 6

What does dual-energy X-ray absorptiometry (DXA) primarily measure when assessing bone density?

  1. ABone mineral content divided by projected bone area
  2. BThree-dimensional bone mineral concentration
  3. CBone turnover rate from blood flow
  4. DCortical thickness at every point in the skeleton
Show answerCorrect answer: A

DXA reports areal bone mineral density, calculated as bone mineral content divided by the projected area of the scanned region. It is a two-dimensional measure rather than a volumetric density.

Question 7

Why is limiting the DXA scan field to the required anatomy useful?

  1. AIt avoids unnecessary scanning and can reduce the chance of including irrelevant structures
  2. BIt increases the patient's bone mineral content
  3. CIt guarantees a higher T-score
  4. DIt eliminates the need for correct region-of-interest placement
Show answerCorrect answer: A

A properly selected scan field covers the anatomy needed for the examination without unnecessary coverage. Appropriate field selection supports efficient imaging and can help avoid irrelevant anatomy or artifacts affecting analysis.

How to use this practice test

The free practice session presents up to 20 randomly selected questions from the 50-question bank. Use each item to test DXA acquisition, artifact recognition, measurement interpretation, quality control, and workflow decisions. Results appear after the session, helping you identify which sampled topics need another review.

Preparation tips

  • For artifact questions, distinguish metal-related attenuation from anatomy and consider whether the affected region can support valid analysis.
  • Review DXA measurement concepts, including the purpose of BMAD in accounting for bone size in children.
  • Practice choosing an alternate skeletal measurement site when spine or hip results are unavailable or unreliable.
  • Connect phantom quality-control scans, scanner consistency, and cross-calibration to the comparability of serial measurements.
  • For workflow scenarios, identify immediate steps that preserve patient safety, image interpretability, and examination data integrity.
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