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.
Numbers in brackets link to the official sources listed under Sources & last verified. Dates that have passed are removed automatically.
| Item | Detail | Source · Verified |
|---|---|---|
| Number of questions | 150 multiple-choice questions (125 scored, 25 pretest)[1] | International Society for Clinical Densitometry · Oct 25, 2026 |
| Passing score | Scaled score, reported pass/fail (modified Angoff cut score)[2] | International Society for Clinical Densitometry · Oct 25, 2026 |
| Retake policy | Wait 30 days; up to 3 attempts within 1 year of the first failure[1] | International Society for Clinical Densitometry · Oct 25, 2026 |
| Validity | 5 years[1] | International Society for Clinical Densitometry · Oct 25, 2026 |
| Renewal | 35 CE/CME credits per 5-year cycle plus current membership or MOC dues ($100/yr non-members)[3] | International Society for Clinical Densitometry · Oct 25, 2026 |
| Delivery | Computer-based at PSI test centers worldwide[1] | International Society for Clinical Densitometry · Oct 25, 2026 |
| Eligibility | Meet all requirements of 1 of 3 options (e.g., current CBDT/CDT/ARRT(BD))[1] | International Society for Clinical Densitometry · Oct 25, 2026 |
| Score release | Unofficial score at end of exam; registry listing within 2 weeks[2] | International Society for Clinical Densitometry · Oct 25, 2026 |
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.
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.
| Official content area | Practice on this site |
|---|---|
| Bone Concepts[5] | DEXA Anatomy & Physiology of Bone Structure Practise bone structure, how bone remodels, and how osteoporosis changes bone mineral density at the sites you scan. |
| Radiation Safety and Science[5] | DEXA Radiation Safety & Patient Preparation Practise ALARA principles, typical DEXA dose levels, pregnancy screening and how to protect staff and patients. |
| Scan Acquisition[5] | DEXA Scan Operation & Technique Practise patient positioning for the spine, hip and forearm, choosing the right site, and spotting artifacts before you finish the scan. |
| Scan Analysis[5] | DEXA Data Interpretation & Reporting Practise placing regions of interest, excluding vertebrae correctly, reading T-scores and Z-scores, and using precision and least significant change for follow-up scans. |
| Technology and Equipment[5] | DEXA Quality Assurance & Equipment Calibra... Practise daily phantom quality control, reading calibration trends, and knowing when a machine change means a new precision baseline. |
Prepare for the DEXA - DEXA Bone Density Scan Certification exam with our free practice test modules. Each quiz covers key topics to help you pass on your first try.
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.
Question: What is the recommended minimum number of repeat scans used to calculate an in-vivo precision assessment for a DEXA technologist?
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.
Question: Which risk management approach is MOST effective for DEXA professionals when evaluating potential workplace hazards?
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.
Question: What is the typical radiation dose in a DEXA scan?
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.
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.
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.
The CBDT exam has 150 multiple-choice questions. Of these, 125 are scored and 25 are pretest questions that do not count toward your result. You take it on a computer at a PSI test center, and PSI has locations worldwide. Treat every question with the same care, and use timed practice sets to get used to the exam's length.
ISCD does not publish a fixed raw passing score. Scores are scaled and reported as pass or fail, with the cut score set by a modified Angoff method. You get an unofficial score report when you finish the exam. If you fail, you also get an analysis of your performance that shows where to focus before a retake.
Yes. You must wait 30 days from your fail date before you submit a retake application. You can make up to 3 attempts within 1 year of the first failure. Use the score analysis you receive after a fail to choose which practice sets to repeat before your next attempt.
The CBDT certification is valid for 5 years. To renew, you need 35 CE/CME credits per 5-year cycle. You also need current ISCD membership or must pay Maintenance of Certification (MOC) dues, which are $100 per year for non-members. Check the ISCD maintenance of certification page for the current rules before your cycle ends.
You must meet all the requirements under 1 of 3 eligibility options set by ISCD. Holding a current CBDT, CDT or ARRT(BD) credential is an example of how you might qualify. Each option has its own requirements, so read the ISCD CBDT page and handbook to confirm which option fits you before you apply.
No. We wrote the questions on this page for practice, with help from AI tools. They are not taken from the real exam. They follow the topics in the official ISCD content areas so you can find gaps and practise the reasoning. For official details, rely on the ISCD CBDT handbook.
How we verify: editorial & fact-checking policy. Report an error: contact us.