- Which Exam This Cheat Sheet Covers
- The Numbers That Define the Written Exam
- Physics Block: Domains 1-8 at a Glance
- Imaging Block: Domains 9-18 at a Glance
- Fees, Eligibility and Delivery Mechanics
- Oral Examination Facts
- Staying Certified: OCC Quick Reference
- Sequencing Your Review by Domain
- Facts You Should Not Assume
- Frequently Asked Questions
- The written exam is 300 multiple-choice questions in three 100-minute sections: about 50 physics and 250 imaging items.
- The passing score is scaled 500 on a 200-800 scale; the issuer publishes no domain percentage weights.
- Written and oral fees are $800 each, so the two standard initial-stage fees total $1,600.
- Imaging content dominates: Domains 9-18 cover Neuroradiology through Nuclear Medicine, including breast, pediatric and vascular/interventional.
Which Exam This Cheat Sheet Covers
This page is a one-page review of Primary Certification in Diagnostic Radiology issued by the American Osteopathic Board of Radiology (AOBR), with AOA certification approval. It is not the ABR Core exam, not an ARRT technologist credential and not a radiation oncology exam. If a fact in another source mentions a different certifying body, a different fee schedule or a different blueprint, it does not belong in your preparation for this pathway.
Use this sheet as a fast reference alongside the deeper material on the site. For a full preparation plan, see the Diagnostic Radiology Study Guide 2026: How to Pass on Your First Attempt, and for a domain-by-domain breakdown, the Diagnostic Radiology Exam Domains 2026: Complete Guide to All 18 Content Areas.
The Numbers That Define the Written Exam
Memorize these figures first. They shape how you pace yourself and how you allocate review time.
| Item | Fact |
|---|---|
| Format | 300 multiple-choice questions |
| Sections | Three sections of 100 minutes each |
| Total testing time | Five hours, with optional ten-minute section breaks outside that time |
| Question split | Approximately 50 physics and 250 imaging |
| Domain weights | Not published as percentages |
| Passing score | Scaled 500 on a 200-800 scale |
The issuer gives approximate counts for the two parts but no percentage weights, so do not convert the counts into percentages or assume that each of the eighteen listed topics carries equal weight. The practical takeaway is simple: roughly five of every six questions are imaging questions, which makes the imaging block the larger share of your study hours even though physics is where many candidates feel least comfortable. More on scoring is in the Diagnostic Radiology Passing Score 2026: Exactly What You Need to Pass article.
Physics Block: Domains 1-8 at a Glance
Domains 1-8 reproduce the Part I physics topic bullets. Expect these to account for the smaller share of the exam, but they reward precise recall of mechanisms and safety concepts.
Domain 1: Biological effects and safety
Know how radiation interacts with tissue and what that means for patients and staff.
- Distinguish the categories of biological effect and the setting in which each matters
- Connect dose concepts to protective practice
Domain 2: Radiological Physics (radiation production and interaction with matter)
The foundation for everything that follows.
- How x-rays are produced and what shapes the beam
- Interaction mechanisms with matter and how they drive image contrast
Domain 3: Radiation Biology (health effects)
Health consequences of exposure and how they are framed clinically.
- Be ready to reason from exposure scenario to expected effect
Domain 4: Radiation Safety and Protection
Practical protection principles applied in a department.
- Shielding, time, distance and dose-limitation thinking
- Patient and personnel protection scenarios
Domain 5: Radiological Imaging (radiography, fluoroscopy, CT, mammography)
Image formation and quality across modalities that use ionizing radiation.
- Technical factors and their effect on image quality and dose
- Modality-specific considerations for fluoroscopy, CT and mammography
Domain 6: Ultrasound
Physics of sound in tissue and how it becomes an image.
- Transducer behavior, resolution trade-offs and artifacts
Domain 7: MRI
Principles of signal generation and contrast.
- Sequence behavior, tissue contrast and artifact recognition
- MR safety principles
Domain 8: Nuclear Medicine
Physics of radiopharmaceuticals and detection.
- Decay, detection and imaging principles as they apply to clinical studies
Notice that Ultrasound and Nuclear Medicine appear twice in the full list, once in the physics part and once in the imaging part. The repetition is intentional: the first appearance tests physical principles, the second tests clinical diagnosis. Study them as two different skill sets.
Imaging Block: Domains 9-18 at a Glance
Domains 9-18 reproduce Part II: Diagnostic Imaging, which is where roughly 250 of the 300 questions live. The ten headings below also map to the ten oral subject areas, so they serve double duty.
| Domain | Name | What to anchor on |
|---|---|---|
| 9 | Neuroradiology | Pattern recognition across brain, head and spine imaging |
| 10 | Vascular/Interventional Radiology | Vascular anatomy, angiographic findings, procedural indications and complications |
| 11 | Cardiopulmonary | Chest radiographic and CT patterns, cardiac and pulmonary disease |
| 12 | Genitourinary Tract | Renal, ureteral, bladder and reproductive-tract imaging |
| 13 | Ultrasound | Clinical sonographic diagnosis and recognition of artifacts |
| 14 | Breast Radiology | Mammographic and breast-imaging interpretation |
| 15 | Gastrointestinal Tract | Contrast studies, CT and abdominal imaging patterns |
| 16 | Musculoskeletal | Bone, joint and soft-tissue pathology across modalities |
| 17 | Pediatric Radiology | Age-specific disease patterns and normal variants |
| 18 | Nuclear Medicine | Clinical scan interpretation and diagnostic correlation |
Because the exam is built around images, your study should be image-first. Reading about pneumothorax or a pediatric fracture pattern is not the same as recognizing it under time pressure. The How Hard Is the Diagnostic Radiology Exam? Complete Difficulty Guide 2026 article explains why recognition speed, not just knowledge, is what separates comfortable passes from close calls. When you are ready to test yourself under realistic conditions, the Diagnostic Radiology practice test is the place to start.
Fees, Eligibility and Delivery Mechanics
Fee quick reference
Written and oral examination fees are $800 each, including the listed corresponding reexamination fees. By addition, the two standard initial-stage fees total $1,600. Anything beyond that, such as review materials, licensure costs or travel, is separate and outside the issuer's fee table. A fuller itemization lives in the Diagnostic Radiology Certification Cost 2026: Complete Pricing Breakdown.
Eligibility checklist
- A qualifying medical degree, or a valid ECFMG pathway
- A one-year approved internship
- A four-year diagnostic-radiology residency that includes 700 nuclear-medicine training hours
- Active licensure
- Ethics and training approval
Remote delivery
The written examination can be taken with remote proctoring that follows MonitorEDU Secure Browser/PARADIGM instructions. Run the technical checks well before test day rather than discovering a compatibility problem in the final hour.
Dates
The timeline page and the oral page do not fully agree on oral application dates: the timeline lists calendar dates while the oral page uses relative application windows. Treat the official pages as the authority and verify before you plan travel or leave. For general scheduling context, see Diagnostic Radiology Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
Oral Examination Facts
Oral entry requires success on the written examination and fourth-year or later training. The oral page states the following:
- The session runs 4.5 hours
- Eight cases are described
- Each case is allotted 20 minutes
- Passing requires success at all ten stations
These statements are quoted as published; they do not support a reconciled oral case count or any derived timer, so do not invent arithmetic to make them line up. What you can rely on is that all ten oral subject headings sit within Domains 9-18, which means your imaging-block review feeds directly into oral preparation. Practice presenting findings aloud, structuring a differential and committing to a diagnosis, because the oral format rewards verbal clarity as much as raw recall.
Staying Certified: OCC Quick Reference
Continuing certification is governed by AOBR's OCC (osteopathic continuous certification) program. The current components are:
| Component | Requirement |
|---|---|
| Enrollment and fee | Automatic enrollment for time-limited diplomates; $300 annual fee |
| CME (2025-2027) | 60 credits per three-year cycle, with no category or specialty quota |
| Self-assessment | 15 SAMs/SA-CME per three-year cycle, also counting toward CME |
| Licensure and practice performance | Maintain active licensure; complete one practice-performance assessment per cycle |
| Cognitive assessment | Replaces the former ten-year OCC examination |
Key Takeaway
For 2025-2027, the component-specific CME guidance (60 credits, no category or specialty quota) takes precedence over the older specialty-credit wording in the OCC overview. If you see a conflicting number in an older document, defer to the current component page. Also note that the 2013 policies document describes a historical separate-exam structure and legacy ten-year certificates; it is not a current blueprint and should not be read as a blanket rule for new certificate validity.
Whether the credential justifies all of this ongoing effort is a fair question, and the Is the Diagnostic Radiology Certification Worth It? Complete ROI Analysis 2026 article tackles it directly, while the Diagnostic Radiology Salary Guide 2026: Complete Earnings Analysis covers compensation context.
Sequencing Your Review by Domain
A compact plan beats an elaborate one. This sequence front-loads physics because it is the most compressible block and then moves into the large imaging block, with weeks tied to the specific domains above.
Physics foundation (Domains 1-5)
- Radiation production, interaction, biology and protection
- Technical factors for radiography, fluoroscopy, CT and mammography
Ultrasound, MRI and nuclear physics (Domains 6-8)
- Artifacts, sequence behavior, detection principles
High-volume imaging (Domains 9, 11, 15, 16)
- Neuroradiology, Cardiopulmonary, Gastrointestinal Tract and Musculoskeletal images, read aloud
Remaining imaging (Domains 10, 12, 13, 14, 17, 18)
- Vascular/Interventional, Genitourinary, Ultrasound, Breast, Pediatric and Nuclear Medicine cases
Adjust the timeline to your own residency rotations and strengths; the point is to cover the physics block quickly, then spend the bulk of your hours on images. If you want a longer-form plan with additional strategy, the study guide expands on this.
Facts You Should Not Assume
A good cheat sheet is as clear about unknowns as it is about knowns. Keep these cautions in mind:
- No verified pass rate. No AOBR diagnostic-radiology pass rate has been verified. Statistics from the ABR or from residency-level programs are not valid substitutes. See Diagnostic Radiology Pass Rate 2026: What the Data Shows for how to think about this gap.
- No published domain percentages. Only approximate question counts for the two parts are given.
- Eighteen is a count of listed topic entries, not an issuer-declared number of top-level domains.
- New-certificate validity term. A specific validity period for newly issued certificates is not independently asserted here; confirm it with the AOBR.
For background on the credential itself, you can read Diagnostic Radiology Certification and What Is Diagnostic Radiology Certification?, and for career context, Diagnostic Radiology Jobs.
Frequently Asked Questions
There are 300 multiple-choice questions delivered in three 100-minute sections, for five hours of testing. The issuer describes approximately 50 physics questions and 250 imaging questions.
The written passing score is scaled 500 on a 200-800 scale. The issuer does not publish domain percentage weights, so a raw-percentage target is not something this sheet can state.
Written and oral fees are $800 each, including the listed corresponding reexamination fees. The two standard initial-stage fees total $1,600 by addition.
Yes. Oral entry requires success on the written examination and fourth-year or later training. The oral page describes a 4.5-hour session and passing all ten stations.
Under current OCC, time-limited diplomates are automatically enrolled and pay a $300 annual fee. Each three-year cycle calls for 60 CME credits, 15 SAMs/SA-CME, active licensure and one practice-performance assessment, along with a current cognitive assessment that replaces the former ten-year OCC examination.