DEXA Practice Test

The Certified Bone Densitometry Technologist (CBDT) exam from the International Society for Clinical Densitometry (ISCD) is for technologists who perform DEXA bone density scans. This page has free practice sets grouped by topic and a map of the official content areas. It also explains sample questions in full and lists the key exam facts: 150 multiple-choice questions, pass/fail scaled scoring, and a certification that lasts 5 years.

DEXA Exam at a Glance

What changed for DEXA in 2026

• Oct 25, 2026: Renewal changed to 35 CE/CME credits per 5-year cycle plus current membership or MOC dues ($100/yr non-members) (previously 35 CE/CME credits per 5-year cycle plus current membership or MOC dues ($125/yr non-members), or re-pass the exam).^[3]
• Oct 25, 2026: Eligibility changed to Meet all requirements of 1 of 3 options (e.g., current CBDT/CDT/ARRT(BD)) (previously Current CBDT/CDT/ARRT(BD), OR allied health degree/cert or 12 CE/CME credits + 3 months DXA experience + 100 central DXA scans).^[1]
• Oct 25, 2026: Other (update 2027-01-01) changed to ARRT's revised Bone Densitometry (BD) content specifications, a related DXA credential, take effect January 1, 2027, adding trabecular bone score and whole-body DXA. (previously ARRT's revised Bone Densitometry (BD) examination content specifications, a related DXA credential, take effect January 1, 2027. They add trabecular bone score, whole-body DXA and follow-up scanning, and change dose terminology.).^[4]

What the DEXA is and how it works

According to International Society for Clinical Densitometry, “The CBDT® examination will have a total of 150 multiple choice questions, 125 scored and 25 pretest questions.”^[1]

The International Society for Clinical Densitometry (ISCD) awards the CBDT credential. It shows that a technologist can acquire and analyse DEXA bone density scans safely and accurately. The certification is valid for 5 years.

Delivery and format. The exam is computer-based and offered at PSI test centers worldwide. It has 150 multiple-choice questions. Of these, 125 are scored and 25 are pretest questions that do not count toward your result.

Scoring. Scores are scaled and reported as pass or fail. The cut score is set with a modified Angoff method. You get an unofficial score report as soon as you finish. Candidates who fail also get an analysis of their performance. Your registry listing follows within 2 weeks.

Eligibility. You must meet all the requirements of 1 of 3 eligibility options. Holding a current CBDT, CDT or ARRT(BD) credential is an example of how you might qualify. The requirements differ by option, so check the ISCD CBDT page before you apply.

Retakes and renewal. If you fail, you must wait 30 days from your fail date before you send a retake application. You can make up to 3 attempts within 1 year of the first failure. To renew, you need 35 CE/CME credits per 5-year cycle plus current ISCD membership or MOC dues ($100 per year for non-members). Fees and policies can change, so confirm them in the current ISCD CBDT handbook.

DEXA content outline and where to practise each area

The content areas below are copied from the official DEXA content outline published by International Society for Clinical Densitometry. The right-hand column shows which of our practice sets covers it.

Worked examples: how to reason through DEXA questions

These are practice questions written for this site, not questions from the real exam. Each explanation shows why the right answer is right and why the others are wrong.

Example 1

Question: What is the recommended minimum number of repeat scans used to calculate an in-vivo precision assessment for a DEXA technologist?

1. 30 patients scanned twice or 15 patients scanned three times
2. 10 patients scanned once
3. 5 patients scanned five times each
4. 50 patients scanned once and averaged

Answer: A. 30 patients scanned twice or 15 patients scanned three times

Explanation:

A is correct. For an in-vivo precision assessment, ISCD guidance calls for real patients scanned more than once, with repositioning between scans. You can scan either 30 patients twice or 15 patients three times. Both designs give enough repeat data to calculate a reliable least significant change (LSC). B is wrong because a patient scanned once gives no repeat measurement, so you cannot calculate precision. C uses too few patients. Extra scans on a small group do not represent your patient population. D scans each patient once, and averaging across different people measures how patients differ from each other, not how well you reproduce a scan. Rule to remember: precision needs repeat scans on the same patients, repositioned each time, in the numbers ISCD specifies. You then use the result to set the LSC for follow-up comparisons.

Example 2

Question: Which risk management approach is MOST effective for DEXA professionals when evaluating potential workplace hazards?

1. Reactive analysis after incidents occur
2. Proactive hazard identification and assessment
3. Relying solely on historical accident data
4. Delegating all safety decisions to management

Answer: B. Proactive hazard identification and assessment

Explanation:

B is correct. Proactive hazard identification means looking for risks before anyone is hurt. You check room layout, equipment condition, patient transfer routes, trip hazards and radiation safety practice. Then you fix the problems or add controls. A is reactive and acts only after harm has happened. C is too narrow, because past accident data misses new equipment, new procedures and near misses that were never recorded. D leaves out the technologist, who sees the work every day. Staff share the job of spotting and reporting hazards. Rule to remember: when a question asks for the most effective safety approach, choose the option that prevents harm in advance and involves the people doing the work. Do not choose the option that responds after the fact or hands responsibility to someone else.

Example 3

Question: What is the typical radiation dose in a DEXA scan?

1. High
2. Moderate
3. Very high
4. Low

Answer: D. Low

Explanation:

D is correct. DEXA uses a very low dose of ionising radiation, much lower than a standard chest X-ray. That is why it is acceptable for screening and for repeated follow-up scans. A and C describe higher-dose imaging such as CT or fluoroscopy, not bone densitometry. B also overstates the dose, because DEXA sits at the low end of diagnostic imaging. A low dose does not mean you can skip precautions. Technologists still follow ALARA, confirm pregnancy status where the protocol requires it, and keep a suitable distance from the source. Rule to remember: DEXA is a low-dose exam. On safety questions, expect correct answers to follow ALARA rather than treat the scan as hazardous.

How to use these practice tests

Download the current CBDT handbook from ISCD and read the content outline so you know what each official area covers. Then take the full practice test without notes to find your weak spots.

• Weak on bone biology: work through Anatomy & Physiology of Bone Structure.
• Weak on positioning and acquisition: use Scan Operation & Technique and Clinical Procedures & Techniques.
• Weak on analysis: use Data Interpretation & Reporting.
• Weak on equipment and safety: use Quality Assurance & Equipment Calibration and Radiation Safety & Patient Preparation.

After each set, read every explanation, including those for questions you got right. Write a short rule for each miss. Spend extra time on precision, least significant change and phantom quality control, because these topics link several areas. In the last stretch before test day, take mixed sets in timed sittings so that working through a 150-question exam feels normal. Confirm your PSI appointment, ID rules and eligibility option directly with ISCD.

Sources & last verified

1. International Society for Clinical Densitometry — number of questions, retake policy, validity, delivery (official source). “The CBDT® examination will have a total of 150 multiple choice questions, 125 scored and 25 pretest questions.” Verified Oct 25, 2026 · source checked Oct 19, 2026.
2. International Society for Clinical Densitometry — passing score, score release (official source). “Scores reported are scaled scores. Candidates receive scores as pass/fail with an analysis provided for those who fail the exam.” Verified Oct 25, 2026.
3. International Society for Clinical Densitometry — renewal (official source). “CBDT Maintenance of Certification (MOC) $100.00” Verified Oct 25, 2026 · source checked Oct 25, 2026.
4. arrt.org — other (official source). “The ARRT Board of Trustees recently approved changes to the following document which goes into effect on January 1, 2027.” Verified Oct 25, 2026 · source checked Oct 19, 2026.
5. International Society for Clinical Densitometry — other (official source). “bone concepts” Verified Oct 28, 2026.

How we verify: editorial & fact-checking policy. Report an error: contact us.