- The Headline Number: 77.1% in 2025
- How to Read That Figure Correctly
- The February 2025 Cut-Score Revision
- Why 75 Is Not 75 Percent
- What the Exam Actually Tests: Where Candidates Win and Lose
- Format and Logistics That Affect Outcomes
- The Eligibility Filter Behind the Statistic
- Attempt Limits, Fees, and the Cost of a Miss
- A Domain-Weighted Prep Sequence
- 2026 Scope Versus the 2027 Specifications
- Frequently Asked Questions
- The ARRT Annual Exam Report - 2025 shows a 77.1% first-time pass rate for Radiation Therapy, based on 958 candidates.
- The passing score is 75 on a 1-99 scaled range, not 75% of questions answered correctly.
- A revised cut-score standard took effect February 1, 2025, while the reported passing score stayed at 75 scaled.
- Procedures carries 103 of the 200 scored questions, making it the largest domain by a wide margin.
The Headline Number: 77.1% in 2025
If you are searching for the Registered Technologist - Radiation Therapy pass rate, the most defensible figure comes straight from the issuer. The American Registry of Radiologic Technologists (ARRT) reported in its Annual Exam Report - 2025 that 77.1% of first-time candidates passed the Radiation Therapy examination in 2025, with a sample of 958 candidates.
That is the number to anchor on. It is specific to this credential, specific to first-time test takers, and specific to a single reporting year. Anything else you read online that lists a different percentage without citing the ARRT report should be treated with suspicion, especially because several unrelated credentials share the "RTT" abbreviation. On this site, RTT refers only to the ARRT Radiation Therapy (T) discipline, earned through the primary pathway.
For a deeper look at how hard candidates find the test, see our companion piece, How Hard Is the RTT Exam? Complete Difficulty Guide 2026.
How to Read That Figure Correctly
A pass rate is only useful when you understand what population it describes. Three details matter here.
First-time candidates only
The 77.1% figure describes people sitting the exam for the first time. It does not blend in repeat test takers, who historically perform differently from first-attempt candidates. If you are a first-time candidate, this is the relevant benchmark for you.
A modest sample size
With 958 first-time candidates, the Radiation Therapy cohort is far smaller than the cohorts for broad imaging disciplines. A smaller population means year-to-year swings can be more pronounced. A few percentage points of movement in either direction is not necessarily a signal of the exam getting easier or harder.
A self-selected, program-vetted pool
Nobody walks into this exam off the street. Candidates have already completed an ARRT-verified radiation therapy educational program, earned an associate degree or higher, and had their clinical competencies verified through in-person direct observation by the program director or designee. That filtering is part of why a specialized credential with a demanding clinical component can still show a pass rate in the high 70s.
The February 2025 Cut-Score Revision
One factor that deserves attention when interpreting recent data: a revised examination cut-score standard took effect February 1, 2025. ARRT announced the change in advance through a news notice, and it applies to the Radiation Therapy examination.
Two points are worth keeping straight:
- The cut-score standard was revised, meaning the underlying judgment about how much knowledge defines minimally competent performance was updated.
- The reported passing score did not change. It remains 75 on the scaled score.
Because the 2025 calendar year straddles that effective date, the 77.1% figure reflects a year in which candidates tested under a mix of conditions. If you are comparing 2025 against earlier years, treat the comparison cautiously; the exam's difficulty reference point shifted partway through. For the mechanics of how scores are reported, read our explainer on the RTT passing score.
Why 75 Is Not 75 Percent
The single most common misunderstanding about this exam is the passing score. ARRT reports results on a scaled score range of 1-99, and a 75 is the passing standard. That is not the same as getting 75% of questions right.
Scaled scoring exists so that scores remain comparable across different exam forms. Because forms are assembled from different sets of questions, one version may be marginally harder than another. The scale adjusts for that so that a candidate is held to the same standard regardless of which form they received.
| Concept | What It Means for You |
|---|---|
| Passing score | 75 on ARRT's 1-99 scaled range |
| Scored questions | 200 of the 230 total items |
| Unscored pilot questions | 30 items, indistinguishable from scored ones |
| Raw percent required | Not published as a fixed percentage; do not assume 75% |
Practically, this means you should never try to reverse-engineer a "safe" number of questions you can miss. Aim for broad competence across all three domains instead. Our full breakdown lives in the article on the exact RTT passing score.
What the Exam Actually Tests: Where Candidates Win and Lose
The pass rate is the outcome; the content specifications are the cause. For examinations through January 31, 2027, the controlling document is the Radiation Therapy Examination Content Specifications (board approved January 2021, effective January 1, 2022). The 200 scored questions are allocated across three official major content categories. ARRT's allocations are counts, so we present them as counts rather than percentages.
| Domain | Scored Questions (of 200) | Subcategories and Counts |
|---|---|---|
| Patient Care | 46 | Patient Interactions and Management (29); Patient and Medical Record Management (17) |
| Safety | 51 | Radiation Physics and Radiobiology (21); Radiation Protection, Equipment Operation, and Quality Assurance (30) |
| Procedures | 103 | Treatment Sites and Tumors (26); Treatment Volume Localization (18); Prescription and Dose Calculation (24); Treatments (35) |
Notice the imbalance. Procedures alone accounts for 103 scored questions, which is more than Patient Care and Safety combined (97). A candidate who is strong on communication and radiation protection but vague on dose calculation and treatment delivery is gambling against the structure of the exam. For a domain-by-domain walkthrough, see RTT Exam Domains 2026: Complete Guide to All 3 Content Areas.
Domain 3: Procedures (103 questions)
This is where the exam is won or lost. It rewards candidates who can move from anatomy and tumor behavior to localization, prescription math, and delivery.
- Treatments (35): the single largest subcategory, covering delivery of therapy.
- Treatment Sites and Tumors (26): site-specific considerations for common treatment locations.
- Prescription and Dose Calculation (24): numerical reasoning, which is where on-screen calculator fluency pays off.
- Treatment Volume Localization (18): simulation and target definition concepts.
Domain 2: Safety (51 questions)
Safety blends physics, biology, and day-to-day quality assurance in a department that operates high-energy equipment.
- Radiation Protection, Equipment Operation, and Quality Assurance (30): the larger half of this domain.
- Radiation Physics and Radiobiology (21): the scientific foundation underneath dose and biological response.
- SI units are the primary system, so make sure unit conversions are second nature.
Domain 1: Patient Care (46 questions)
Often underestimated because it feels intuitive, but 46 scored items is a meaningful share of the exam.
- Patient Interactions and Management (29): communication, patient condition, and care during treatment courses.
- Patient and Medical Record Management (17): documentation and record accuracy.
Scope limits that save you study time
The content specifications also tell you what the exam does not go deep on, which is valuable for calibrating effort:
- Brachytherapy coverage is limited to basic common-use, surrounding-tissue-dose, and radiation-protection concepts. It does not extend to detailed procedures or isotope characteristics.
- Staging is limited to basic concepts rather than site-specific staging systems.
- Specific CPT codes are excluded.
If you have been memorizing isotope half-lives or detailed staging tables, you may be investing in material the exam deliberately keeps shallow.
Format and Logistics That Affect Outcomes
Pass rates are also shaped by test-day mechanics. Know these before you sit.
- Delivery: computer-based at Pearson VUE test centers.
- Length: 230 total questions, made up of 200 scored and 30 unscored pilot items. You cannot tell which are which, so treat every question as if it counts.
- Time: 230 minutes of examination answering time, within a 250-minute appointment that also covers the tutorial, nondisclosure agreement, and survey.
- Item types: primarily single-best-answer multiple choice, with possible alternative formats and image-based questions. The ARRT handbook also describes multiple-response and ordered-response formats.
- Navigation: you must answer each item before advancing, but you may flag questions and revisit them.
- Resources: closed book. Basic and scientific on-screen calculators are available, and Pearson can supply a basic four-function calculator on request. Personal calculators are prohibited.
The Eligibility Filter Behind the Statistic
Understanding who is allowed to sit the exam helps explain why the pass rate is what it is. The primary pathway requires:
- An associate degree or higher from an ARRT-recognized accredited institution. The degree may be in any major, and it must be conferred before the examination.
- Completion of an ARRT-verified radiation therapy educational program and its didactic and clinical competencies.
- Compliance with ARRT ethics requirements.
An existing Radiography credential is not a universal prerequisite, which distinguishes this discipline from some postprimary routes. The degree must be earned and the application submitted no more than three years after program completion, and that deadline is separate from the later three-year examination-attempt period.
Clinical competency is heavy
Before you can test, your program verifies a substantial set of hands-on requirements through in-person direct observation (remote or virtual observation is not accepted). These include 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, one specialized accessory-device construction process, and 16 radiation treatment procedures (at least 13 on patients and no more than three simulated).
That experience is a large part of why candidates arrive prepared. It also means your clinical rotations are your best study resource for Procedures content. For the complete eligibility picture, read RTT Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Attempt Limits, Fees, and the Cost of a Miss
A pass rate that leaves roughly one in four first-time candidates short is a reminder to understand the retake rules before you test.
| Item | Detail |
|---|---|
| Initial application fee | $225 USD |
| Examination reapplication fee | $200 USD |
| Attempts allowed | Three attempts within three years of the opening of your initial examination window |
| Annual renewal after certification | $65, regardless of the number of ARRT credentials |
Each reattempt costs $200 in reapplication fees, so a first-attempt miss carries a real financial and scheduling cost on top of the stress. The three-attempt, three-year window creates a hard ceiling, which makes the first attempt the most valuable one. Full pricing context is in RTT Certification Cost 2026: Complete Pricing Breakdown, and scheduling specifics are in RTT Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
Key Takeaway
Treat attempt one as the attempt that counts. With a fixed three-attempt window and a $200 reapplication fee after the initial $225 application, readiness before you schedule is cheaper than recovery afterward.
A Domain-Weighted Prep Sequence
The pass-rate data suggests most prepared candidates succeed, and the content specifications tell you where to point your effort. Here is one way to sequence an eight-week plan around the exam's actual weighting rather than around generic habits.
Safety foundations first
- Radiation physics, radiobiology, and SI unit fluency, since these underpin dose questions later.
- Radiation protection, equipment operation, and quality assurance (the larger Safety subcategory at 30 questions).
Procedures, the heavyweight
- Prescription and dose calculation: drill on-screen calculator workflow until it is automatic.
- Treatment volume localization, then treatment sites and tumors.
- Treatments, the largest single subcategory at 35 questions, with attention to delivery concepts.
Patient Care and records
- Patient interactions and management (29), then medical record management (17).
- Review ethics and documentation scenarios.
Timed integration
- Full-length timed sets against the one-minute-per-question benchmark.
- Review flagged-question strategy and ordered-response formats.
This sequencing is deliberate: Safety concepts feed the math in Procedures, and Procedures gets the most calendar time because it holds 103 of 200 scored questions. For a full preparation framework, see the RTT Study Guide 2026: How to Pass on Your First Attempt, and keep the RTT Cheat Sheet 2026 handy for last-week review. You can also test your readiness with timed questions on our RTT practice test site.
2026 Scope Versus the 2027 Specifications
If you are testing in 2026, study to the 2026 scope. The Radiation Therapy Examination Content Specifications (V.2021.02.25, effective January 1, 2022) govern examinations through January 31, 2027. A separate set of 2027 Radiation Therapy Content Specifications becomes effective February 1, 2027.
Do not blend the two. Candidates who study from a 2027 outline for a 2026 sitting risk spending time on material weighted differently than the exam they will actually take. When you read any prep resource, confirm which specification it references. As always, verify directly with ARRT before scheduling, because the issuer's documents are the controlling source.
Frequently Asked Questions
The most recent verified figure is from the ARRT Annual Exam Report - 2025, which shows 77.1% of first-time Radiation Therapy candidates passing in 2025 (n=958). We do not present a 2026 percentage because no verified 2026 figure was available in the sources reviewed.
No. The passing score is 75 on ARRT's 1-99 scaled-score range. Scaled scores account for differences between exam forms, so 75 does not mean 75% correct. See our guide to the RTT passing score for detail.
A revised cut-score standard took effect February 1, 2025, but the reported passing score remains 75 scaled. Because that date falls mid-year, comparisons between 2025 and earlier years should be made cautiously rather than treated as proof the exam became easier or harder.
You have three examination attempts within three years of the opening of your initial examination window. Each reapplication costs $200 USD, following the initial $225 USD application fee.
Procedures, which carries 103 of the 200 scored questions, with Treatments (35), Treatment Sites and Tumors (26), Prescription and Dose Calculation (24), and Treatment Volume Localization (18). Then cover Safety (51) and Patient Care (46) so no domain is left weak.
The 77.1% first-time pass rate is encouraging, but it describes a pool of candidates who arrived with accredited education and verified clinical competencies. Your best move is to map your preparation to the 200 scored questions and the 103 that sit in Procedures. Start with our RTT study guide, check cost and timing in RTT Certification Cost 2026, and weigh long-term value in Is the RTT Certification Worth It?. When you are ready to measure yourself against exam-style questions, head to the RTT Exam Prep practice tests.