- What the Credential Actually Is
- Who Issues It and How the Exam Is Delivered
- Eligibility: Degree, Program, and Ethics
- The Clinical Competency Load
- Exam Format and Question Style
- The Three Content Domains
- Scoring, Attempts, and the Pass Rate
- Fees and Registration Mechanics
- Keeping the Credential Active
- Where Certified Therapists Work
- Sequencing Your Preparation by Domain
- Frequently Asked Questions
- RTT here means Registered Technologist - Radiation Therapy, an ARRT credential in the Radiation Therapy (T) discipline.
- The exam has 230 questions: 200 scored plus 30 unscored pilot items, delivered at Pearson VUE test centers.
- A passing score is 75 on a 1-99 scaled range, not 75% of questions correct.
- Procedures carries 103 of 200 scored questions, more than Patient Care (46) and Safety (51) combined.
What the Credential Actually Is
Registered Technologist - Radiation Therapy is the credential that tells employers, patients, and state licensing boards that a radiation therapist has met a national standard for education, ethics, and examination performance. In ARRT's official terminology, the discipline is Radiation Therapy, designated (T). "RTT" is the shorthand used on this site for that credential; it is not ARRT's own discipline designation, which is why the formal wording matters when you list your credentials on a resume or badge.
If you landed here searching for a definition, the short answer is this: the credential belongs to the clinician who plans and delivers radiation treatment under the direction of a radiation oncologist. That means positioning patients, operating linear accelerators and related equipment, verifying treatment setups, performing simulation procedures, calculating doses, and supporting patients through a course of treatment that often runs for weeks. Our companion pages cover the vocabulary side in detail, including What Is RTT? and What Does RTT Stand For?.
One point deserves emphasis early. This is a primary pathway credential. You do not earn it as a postprimary add-on after sitting for a Radiography examination. An existing Radiography credential is not a universal prerequisite, so candidates can enter through a radiation therapy program directly.
Who Issues It and How the Exam Is Delivered
The credential is issued by the American Registry of Radiologic Technologists (ARRT). ARRT sets eligibility rules, writes and scores the examination, and administers the ongoing requirements that keep a credential active. Examinations are delivered through Pearson VUE test centers, so you will schedule a seat at a proctored center rather than testing at home or at your program.
That structure matters for planning. ARRT decides whether you are eligible; Pearson VUE handles the appointment itself. Confusing the two is a common source of scheduling mistakes, and our guide to RTT exam dates, testing windows, and scheduling walks through how the pieces fit together.
Eligibility: Degree, Program, and Ethics
Primary eligibility rests on three pillars, and all three must be satisfied before you can be certified.
- An associate degree or higher from an ARRT-recognized accredited institution. The degree may be in any major, but it must be conferred before you sit for the examination.
- Completion of an ARRT-verified radiation therapy educational program, including its didactic coursework and clinical competencies.
- Compliance with ARRT ethics requirements, which covers both conviction history and honest conduct throughout the process.
The degree being allowed in any major is a quiet but useful detail. A candidate whose program awarded a certificate in radiation therapy still needs a qualifying degree conferred separately, and that degree need not be in a health science. For the full checklist, see RTT requirements: eligibility, prerequisites, and how to qualify.
The Clinical Competency Load
What separates this credential from many exam-only certifications is the volume of hands-on documentation required before you ever register. Your program must verify that you have performed a defined set of procedures, and verification has to come from direct observation.
Required Clinical Activities
The competency requirements are specific and countable:
- CPR plus six other patient-care activities
- Five quality-control activities
- Six treatment-simulation procedures
- Dose calculations for six treatment plans
- Fabrication of three accessory devices
- Participation in four special treatment procedures
- One specialized simulation procedure and one specialized accessory-device construction process
- Sixteen radiation treatment procedures, including at least 13 on patients and no more than three simulated
The program director or designee must verify clinical competency through in-person direct observation. Remote or virtual observation is not accepted. Practically, this means your clinical site schedule, not your study schedule, is the true gating factor for how soon you can apply. Document each competency as you complete it rather than reconstructing the record near graduation.
Exam Format and Question Style
The examination is computer-based and closed book. You will see 230 total questions, of which 200 are scored and 30 are unscored pilot questions that ARRT uses to evaluate future items. You cannot tell which are which, so treat every question as if it counts.
| Feature | Detail |
|---|---|
| Total questions | 230 (200 scored, 30 unscored pilot) |
| Answering time | 230 minutes |
| Total appointment | 250 minutes, including tutorial, nondisclosure agreement, and survey |
| Primary item type | Single-best-answer multiple choice |
| Other possible formats | Alternative formats, image-based questions, multiple-response, ordered-response |
| Reference materials | None; closed book |
| Calculators | On-screen basic and scientific; four-function supplied by Pearson on request; personal calculators prohibited |
Two behaviors of the testing interface shape strategy. You must answer each item before advancing, but you may flag questions and revisit them. That combination rewards a disciplined first pass: commit to your best answer, flag anything uncertain, and use remaining time for review rather than leaving blanks you cannot return to.
The calculator rules deserve rehearsal. Because dose calculation is a heavy content area, you should practice with an on-screen scientific calculator, since your personal device will not be allowed in the room. For a candid look at what makes the test demanding, read How Hard Is the RTT Exam?
The Three Content Domains
ARRT organizes the examination into three official major content categories. The scored-question allocations below come directly from the content specifications and are best treated as counts, not percentages you should recompute. This article reflects the specifications that govern examinations through January 31, 2027; a separate set of 2027 content specifications becomes effective February 1, 2027, and should be consulted if your test date falls after that point.
Domain 1: Patient Care (46 of 200 scored questions)
This domain covers the human side of treatment and the records that document it.
- Patient Interactions and Management (29): communication, assessment, side-effect recognition, and supporting patients through treatment
- Patient and Medical Record Management (17): accurate documentation, verification, and record integrity
Domain 2: Safety (51 of 200 scored questions)
Safety blends foundational science with the day-to-day discipline of running equipment correctly.
- Radiation Physics and Radiobiology (21): how radiation interacts with matter and tissue, and why fractionation works as it does
- Radiation Protection, Equipment Operation, and Quality Assurance (30): shielding, monitoring, machine operation, and QA checks
Domain 3: Procedures (103 of 200 scored questions)
This is the dominant domain, accounting for more than half of the scored items.
- Treatment Sites and Tumors (26): anatomy, disease behavior, and site-specific considerations
- Treatment Volume Localization (18): simulation, imaging, and defining the volume to be treated
- Prescription and Dose Calculation (24): turning a prescription into monitor units and verifying the math
- Treatments (35): delivery, setup, verification, and technique
For a deeper walk through each content area, see the complete guide to all three RTT content areas.
Scoring, Attempts, and the Pass Rate
ARRT reports results on a scaled score from 1 to 99, and the passing score is 75. This is a scaled score, not a percentage: earning a 75 does not mean you answered 75% of questions correctly. The conversion accounts for the difficulty of the particular form you received, which keeps standards consistent across versions. A revised examination cut-score standard took effect February 1, 2025, while the reported passing score remains 75 scaled. Details are in our RTT passing score explainer.
You have three examination attempts, and they must fall within three years of the opening of your initial examination window. That window is separate from the application deadline discussed above, which is why a retake plan should be built before your first attempt, not after a disappointing result.
On outcomes, ARRT's Annual Exam Report for 2025 shows a 77.1% first-time candidate pass rate among 958 first-time candidates. Treat that as a single-year snapshot rather than a prediction for any individual. We discuss how to read the figure responsibly in RTT pass rate: what the data shows.
Fees and Registration Mechanics
The fee structure is simple but easy to misread. The initial application fee is $225 USD, and examination reapplication costs $200 USD each time you need to retest. Annual renewal after certification is $65 regardless of how many ARRT credentials you hold.
| Item | Amount (USD) |
|---|---|
| Initial application | $225 |
| Examination reapplication | $200 |
| Annual renewal | $65, regardless of number of ARRT credentials |
Fees change, so confirm current amounts on ARRT's fee page before budgeting. For the full picture including study materials and program-related costs, see the RTT certification cost breakdown.
Keeping the Credential Active
Certification is not a one-time event. To remain in good standing you must renew annually, continue complying with ethics requirements, and complete 24 approved continuing education credits per two-year biennium. Those credits are counted per biennium, not per credential, so holding multiple ARRT credentials does not multiply your CE obligation.
Credentials earned on or after January 1, 2011 also carry Continuing Qualifications Requirements every 10 years. CQR involves a professional profile, a structured self-assessment, and any prescribed CE. ARRT also permits accepting the maximum CQR CE prescription instead of taking the self-assessment, which gives candidates a choice about how to satisfy the requirement.
Key Takeaway
Build your CE habit in your first year of practice. Twenty-four credits across two years is manageable when spread out, and painful when compressed into the final weeks before a biennium closes.
Where Certified Therapists Work
Employment for radiation therapists centers on settings that deliver external-beam treatment. Hospital-based cancer centers, freestanding radiation oncology practices, and academic medical centers are the typical employers, often alongside radiation oncologists, medical physicists, and dosimetrists. Roles can extend beyond the treatment console into simulation, quality assurance, and clinical education as experience grows.
Certification matters in hiring because many employers and state regulators use it as a baseline qualification. To explore openings and the shape of the market, see RTT jobs, and for compensation context read the RTT salary guide. If you are weighing the investment itself, Is the RTT certification worth it? lays out the return-on-investment reasoning.
Sequencing Your Preparation by Domain
Generic study advice is plentiful; the more useful question is how to order the three domains given their weights and how they interact. Because Procedures holds 103 of 200 scored questions, it should anchor your calendar, while Safety's physics underpins the dose calculation you will face there.
Safety foundations first
- Review radiation physics and radiobiology (21 questions) because later dose logic depends on it
- Cover radiation protection, equipment operation, and quality assurance (30 questions)
Procedures, the heavy lift
- Work Prescription and Dose Calculation with the on-screen calculator you will actually use
- Study Treatment Volume Localization, then Treatments (the largest subdomain at 35)
- Cycle through Treatment Sites and Tumors alongside anatomy review
Patient Care and integration
- Cover Patient Interactions and Management and record management
- Take a timed practice set to rehearse the flag-and-return workflow
Adjust the timeline to your program calendar and clinical schedule, but keep the logic: physics before dose math, dose math before treatment delivery, and a timed full-length rehearsal before test day. For a fuller plan, see the RTT study guide, and keep the RTT cheat sheet handy for last-week review. When you are ready to test yourself under realistic conditions, try the RTT practice tests.
Frequently Asked Questions
No. Radiation Therapy (T) is its own ARRT discipline earned through the primary pathway. An existing Radiography credential is not a universal prerequisite, and this is not a Radiography postprimary examination.
No. The 75 is on ARRT's 1-99 scaled-score range. Scaled scoring adjusts for form difficulty, so the raw number of correct answers needed can differ between exam forms.
You have three attempts within three years of the opening of your initial examination window. Each reapplication costs $200 USD, and this attempt period is separate from the initial application deadline after program completion.
No. Personal calculators are prohibited. Basic and scientific on-screen calculators are available, and Pearson can supply a basic four-function calculator on request.
No. The program director or designee must verify clinical competency through in-person direct observation. Remote or virtual observation is not accepted.
Understanding the credential is the first step; the rest is disciplined preparation against the three domains. For additional background on terminology and the path ahead, see RTT certification and RTT training.