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ISCD CCD Certified Clinical Densitometrist

Practice Questions106 questions

Exam Review

Key Facts: ISCD CBDT Exam

150 questions

CBDT exam has 150 multiple-choice items, 125 scored and 25 pretest

ISCD CBDT Candidate Handbook (2025)

3.5 hours

Time allowed to complete the closed-book CBDT examination

ISCD CBDT Candidate Handbook (2025)

5 domains

Bone Concepts, Radiation Safety, Technology, Scan Acquisition, Scan Analysis

ISCD CBDT Content Outline

31%

Scan Acquisition is the largest scored domain on the CBDT exam

ISCD CBDT Content Outline

$375 / $525

CBDT exam fee for ISCD members versus non-members (USD)

ISCD Certification Fees Schedule

100 central scans

Minimum DXA scans at two skeletal sites for the experience pathway

ISCD CBDT Candidate Handbook (2025)

5-year certification

CBDT credential is valid for five years and maintained through MOC

ISCD CBDT Candidate Handbook (2025)

100

Free original CBDT practice questions in this bank

OpenExamPrep

The ISCD CBDT is the NCCA-accredited credential for technologists who perform DXA bone densitometry scans, separate from the physician CCD. The closed-book PSI exam has 150 multiple-choice questions (125 scored plus 25 pretest, with 25 case-based items) and a 3.5-hour limit. Content is weighted Bone Concepts 25%, Radiation Safety and Science 11%, Technology and Equipment 14%, Scan Acquisition 31% and Scan Analysis 19%. The fee is $375 for ISCD members and $525 for non-members, scoring is pass/fail on a scaled cut score, and the certification is valid for five years. This 100-question bank gives original, domain-weighted practice across DXA physics, positioning, quality control, precision/LSC, T-scores/Z-scores and ISCD Official Positions.

Sample ISCD CBDT Practice Questions

Try these sample questions to review concepts for the ISCD CBDT exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Using the WHO diagnostic classification, a T-score of -2.7 at the lumbar spine in a postmenopausal woman is classified as:

A.Normal

B.Low bone mass (osteopenia)

C.Osteoporosis

D.Severe (established) osteoporosis

Explanation: The WHO criteria classify a T-score of -2.5 or lower as osteoporosis, so -2.7 meets that threshold. Severe (established) osteoporosis additionally requires a fragility fracture, which is not stated here.

2A T-score compares a patient's bone mineral density to which reference population?

A.A young adult of the same sex at peak bone mass

B.An age-, sex- and ethnicity-matched population

C.The patient's own previous scan

D.A pediatric reference of the same age

Explanation: A T-score is the number of standard deviations a patient's BMD differs from the mean BMD of a healthy young adult of the same sex at peak bone mass. It is the basis of the WHO diagnostic categories in postmenopausal women and men over 50.

3For which patient should a Z-score, rather than a T-score, be used for the BMD diagnostic statement?

A.A 68-year-old postmenopausal woman

B.A 35-year-old premenopausal woman

C.A 60-year-old man

D.A 72-year-old man

Explanation: ISCD Official Positions state that Z-scores, not T-scores, should be used for premenopausal women, men younger than 50 and children. A 35-year-old premenopausal woman therefore falls into the Z-score group.

4A Z-score of -2.0 or lower in a child or premenopausal woman is best described as:

A.Osteoporosis

B.Below the expected range for age

C.Normal

D.Osteopenia

Explanation: ISCD Official Positions state that a Z-score of -2.0 or lower is defined as 'below the expected range for age', and a Z-score above -2.0 is 'within the expected range for age'. The terms osteoporosis and osteopenia are not applied based on BMD alone in these groups.

5Bone mineral density measured by DXA is most commonly reported in which units?

A.Hounsfield units

B.Grams per cubic centimeter (g/cm3)

C.Grams per square centimeter (g/cm2)

D.Milligrams per deciliter (mg/dL)

Explanation: DXA measures an areal (two-dimensional) bone mineral density expressed in grams per square centimeter (g/cm2). It is areal because DXA projects a three-dimensional bone onto a two-dimensional image.

6Which type of bone has a higher surface-to-volume ratio and a faster metabolic turnover, making it more responsive to early bone loss?

A.Cortical bone

B.Trabecular bone

C.Lamellar bone

D.Woven bone

Explanation: Trabecular (cancellous) bone has a high surface-to-volume ratio and turns over faster than cortical bone, so changes appear there earliest. This is one reason the trabecular-rich spine is sensitive for monitoring.

7In the bone remodeling cycle, which cells are primarily responsible for bone resorption?

A.Osteoblasts

B.Osteoclasts

C.Osteocytes

D.Chondrocytes

Explanation: Osteoclasts are large multinucleated cells that resorb (break down) bone, releasing mineral into circulation. Antiresorptive osteoporosis drugs such as bisphosphonates act by suppressing osteoclast activity.

8An atypical femur fracture (AFF) is most associated with long-term use of which class of medication?

A.Anabolic agents

B.Bisphosphonates

C.Calcium supplements

D.Loop diuretics

Explanation: Atypical femur fractures occur in the subtrochanteric or diaphyseal femoral shaft and are linked to long-term antiresorptive therapy, particularly bisphosphonates. ISCD supports imaging the femur shaft (e.g., AFF scans) to look for early features in at-risk patients.

9Postmenopausal (Type 1) primary osteoporosis is driven mainly by the decline of which hormone?

A.Estrogen

B.Calcitonin

C.Thyroxine

D.Cortisol

Explanation: Type 1 (postmenopausal) osteoporosis results chiefly from estrogen deficiency after menopause, which accelerates osteoclastic resorption and preferentially affects trabecular bone. This raises the risk of vertebral and distal forearm fractures.

10Which of the following is a cause of SECONDARY osteoporosis rather than primary osteoporosis?

A.Normal aging in an 80-year-old

B.Long-term glucocorticoid (steroid) therapy

C.Menopause in a 55-year-old woman

D.Peak bone mass reached at age 30

Explanation: Secondary osteoporosis results from an identifiable disease or medication, such as long-term glucocorticoid therapy, hyperthyroidism or hyperparathyroidism. Primary osteoporosis (Types 1 and 2) is related to menopause and aging.

About the ISCD CBDT Exam

The ISCD Certified Bone Densitometry Technologist (CBDT) is an NCCA-accredited certification for technologists and other allied-health professionals who perform DXA bone densitometry scans. It is distinct from the physician-oriented Certified Clinical Densitometrist (CCD). The closed-book, computer-based exam is delivered at PSI test centers worldwide and contains 150 multiple-choice questions (125 scored, 25 pretest) built on five content domains: Bone Concepts, Radiation Safety and Science, Technology and Equipment, Scan Acquisition and Scan Analysis. The exam emphasizes correct scan acquisition, patient positioning, quality control and precision, T-score and Z-score reporting, the WHO diagnostic classification, and the ISCD Official Positions. Certification lasts five years and is maintained through ISCD's Maintenance of Certification program.

Exam sponsor: International Society for Clinical Densitometry (ISCD), delivered by PSI Services LLC. The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

150 multiple-choice questions: 125 scored and 25 unscored pretest items. 25 of the scored questions are case-based. Five content domains: Bone Concepts (25%), Radiation Safety and Science (11%), Technology and Equipment (14%), Scan Acquisition (31%) and Scan Analysis (19%).

Time Limit

Three and a half hours (210 minutes) to complete the closed-book examination.

Passing Score

Pass/fail using a scaled cut score determined by a periodic ISCD/PSI Cut Score Study; no fixed percentage is published. There is no penalty for wrong answers, so every question should be answered.

Exam / Certification Fees

$375 USD for ISCD Professional or Full Members and $525 USD for community members or non-members; re-test fees are $200 (member) or $300 (non-member).

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

25%

Bone Concepts

Key terms including osteoporosis and low bone mass, BMD, T-scores and Z-scores and FRAX; bone science covering anatomy and physiology, trabecular versus cortical bone, the remodeling cycle and fracture types including atypical femur fractures; and osteoporosis including primary (Type 1/Type 2) and secondary causes, risk factors, prevention, antiresorptive and anabolic treatments, and the Bone Mass Measurement Act.

11%

Radiation Safety and Science

X-ray science and ionizing radiation factors such as time, mA and kVp; the physics of dual-energy X-ray absorptiometry; and radiation protection including ALARA, who to protect (patient, technologist, pregnant women), protection by time, distance and shielding, and radiation dose units and comparisons to natural background and other imaging.

14%

Technology and Equipment

BMD measurement devices and the advantages and limitations of DXA, QCT and QUS; scanner types including pencil-beam and fan-beam systems; and DXA standard practices covering calibration, quality assurance, quality control (spine phantom scanning, shifts and drifts), precision assessment and calculation of the Least Significant Change, cross-calibration when changing systems, and data backup and archiving.

31%

Scan Acquisition

Scan selection (central versus peripheral, site substitution, patient health information and scan mode for body habitus); correct positioning of the lumbar spine, femur/hip and forearm; recognizing artifacts (anatomical, internal and external, motion, contrast agents); serial scanning, reproducibility and using previous scan settings; and other measurements such as total body composition and vertebral fracture assessment (VFA).

19%

Scan Analysis

Placing and adjusting regions of interest, selecting the correct reference database (WHO criteria, NHANES III for the total hip, NOF guidance), applying the WHO diagnostic classification of T-scores, recognizing and correcting analysis and labeling errors, and applying the relevant ISCD Official Positions for the spine, hip and forearm and for which sites and values to report.

Preparing for the ISCD CBDT Exam

What You Need to Know

Passing score: Pass/fail using a scaled cut score determined by a periodic ISCD/PSI Cut Score Study; no fixed percentage is published. There is no penalty for wrong answers, so every question should be answered.
Assessment: 150 multiple-choice questions: 125 scored and 25 unscored pretest items. 25 of the scored questions are case-based. Five content domains: Bone Concepts (25%), Radiation Safety and Science (11%), Technology and Equipment (14%), Scan Acquisition (31%) and Scan Analysis (19%).
Time limit: Three and a half hours (210 minutes) to complete the closed-book examination.
Exam / certification fees: $375 USD for ISCD Professional or Full Members and $525 USD for community members or non-members; re-test fees are $200 (member) or $300 (non-member). Official sources

Using Our Practice Resources

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ISCD CBDT: Suggested Study Strategy

1Download the ISCD CBDT Content Outline and study to its weightings: Scan Acquisition (31%) and Bone Concepts (25%) together make up over half the scored exam, so spend the most time on positioning and core terminology.

2Memorize the WHO T-score thresholds (normal at or above -1.0, osteopenia/low bone mass between -1.0 and -2.5, osteoporosis at or below -2.5) and remember that Z-scores, not T-scores, are used for premenopausal women, men under 50 and children.

3Learn the precision and Least Significant Change workflow: perform an in vivo precision study, calculate the precision error as a root-mean-square SD, and multiply by 2.77 to get the 95% LSC before calling a serial change real.

4Practice the standard positioning rules for each site: lumbar spine straight with legs elevated to flatten lordosis, femur with the leg internally rotated about 15-25 degrees, and forearm using the non-dominant arm scanned at the 33% (one-third) radius.

5Review the ISCD Official Positions on which vertebrae and hip region to use, when to exclude vertebrae with artifacts, and reporting only one valid skeletal site value when others are invalid.

6Run the manufacturer phantom QC daily and know how to interpret shifts and drifts on the QC chart, because calibration and quality control questions appear in the Technology and Equipment domain.

Frequently Asked Questions

What is the difference between the CBDT and the CCD?

The CBDT (Certified Bone Densitometry Technologist) is for technologists and allied-health staff who perform DXA scans, while the CCD (Certified Clinical Densitometrist) is for physicians and advanced providers who interpret them. Both are ISCD credentials but are separate exams.

How many questions are on the CBDT exam and how long is it?

The CBDT exam has 150 multiple-choice questions, of which 125 are scored and 25 are unscored pretest items; 25 of the scored items are case-based. Candidates have three and a half hours to finish the closed-book exam.

How is the CBDT exam scored and what is the passing score?

Scoring is pass/fail based on a scaled cut score set by a periodic ISCD/PSI Cut Score Study, so there is no fixed published percentage. Wrong answers are not penalized, so candidates should answer every question.

How much does the CBDT exam cost?

The exam fee is $375 USD for ISCD Professional or Full Members and $525 USD for community members or non-members. Re-test fees are $200 for members and $300 for non-members.

What are the eligibility requirements for the CBDT?

Candidates must meet one of three pathways: already hold a CBDT, CDT or ARRT(BD) in good standing; hold an allied-health degree plus 3 months of DXA experience and 100 central scans at two sites; or document 12 CME/Category A skeletal-health credits plus that same experience.

How long is the CBDT certification valid?

The CBDT is a five-year certification maintained through ISCD's Maintenance of Certification program, which requires continuing education in musculoskeletal health from at least two sources over the cycle.