- What RTT Means on This Site
- Who Issues the Credential and How It Is Earned
- Eligibility: Degree, Program, and Clinical Competencies
- How the Exam Is Built and Delivered
- The Three Content Domains in Detail
- Scoring, Attempts, and Pass-Rate Context
- Fees and Registration Mechanics
- Scheduling Your Prep Around the Domains
- After You Pass: Renewal, CE, and CQR
- Where Radiation Therapists Work
- Frequently Asked Questions
- RTT here means Registered Technologist - Radiation Therapy, issued by the American Registry of Radiologic Technologists (ARRT) through its primary pathway.
- The exam has 230 questions: 200 scored and 30 unscored pilot items, delivered at Pearson VUE test centers.
- Procedures carries 103 of the 200 scored questions, making it the largest of the three domains.
- A passing score is 75 on ARRT's 1-99 scaled range, not 75% of questions correct.
What RTT Means on This Site
On rttexam.com, RTT stands for Registered Technologist - Radiation Therapy. It is the site's shorthand for the ARRT's Radiation Therapy (T) discipline, the credential held by radiation therapists who deliver prescribed doses of radiation to patients, most often as part of cancer treatment. Worth noting up front: RTT is the abbreviation this site uses, not ARRT's official discipline designation, which is simply Radiation Therapy (T).
If you landed here searching for a definition, you may also want the related explainers on what RTT stands for and the meaning of RTT. This article goes a step further and walks through how the credential is earned, what the exam tests, and how it is maintained.
Who Issues the Credential and How It Is Earned
The American Registry of Radiologic Technologists issues the credential. Candidates earn it through the primary eligibility pathway, which means the Radiation Therapy credential is its own entry point rather than a postprimary add-on to Radiography. An existing Radiography credential is not a universal prerequisite, so you do not need to become a radiographer first.
Earning the credential has three parts: meet the education requirements, satisfy the ethics requirements, and pass the examination. For a broader view of the credential itself, see our overview of RTT certification and the more detailed explainer on what RTT certification is.
Eligibility: Degree, Program, and Clinical Competencies
Primary eligibility has several moving pieces. Candidates need:
- 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 exam.
- Completion of an ARRT-verified radiation therapy educational program, including its didactic coursework and clinical competencies.
- Compliance with ARRT ethics requirements.
Timing matters. The degree must be earned and the application submitted no more than three years after program completion. That initial application deadline is separate from the three-year window for exam attempts, which is covered in the scoring section below. Our RTT requirements guide covers the full qualification picture.
The Clinical Competency Checklist
Radiation therapy has one of the more specific clinical requirement lists among ARRT disciplines. Program-verified competencies 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 and one specialized accessory-device construction process
- Sixteen radiation treatment procedures, with at least 13 performed on patients and no more than three simulated
How the Exam Is Built and Delivered
The exam is computer-based and delivered at Pearson VUE test centers. Here is the structure at a glance:
| Feature | Detail |
|---|---|
| Total questions | 230 |
| Scored questions | 200 |
| Unscored pilot questions | 30 |
| Answering time | 230 minutes |
| Total appointment time | 250 minutes (includes tutorial, nondisclosure agreement, and survey) |
| Delivery | Pearson VUE test center, computer-based |
| Reference materials | Closed book |
Question Styles
Most items are single-best-answer multiple choice. The ARRT handbook also describes multiple-response and ordered-response formats, and image-based questions are possible. Expect to read an image or scenario, then choose the best answer or arrange steps in sequence.
Test-Day Mechanics
- You must answer each item before advancing, but you can flag questions and revisit them.
- Basic and scientific on-screen calculators are available. Pearson can supply a basic four-function calculator on request, and personal calculators are prohibited.
- The 30 pilot questions are unscored but indistinguishable from scored ones, so treat every item seriously.
Because dose calculation is tested, practice with the same style of calculator you will see on screen. For a candid look at how demanding this format feels, see how hard the RTT exam is.
The Three Content Domains in Detail
The ARRT organizes the exam into three major content categories. The scored-question allocations below are official counts out of 200, and this article keeps them as counts rather than converting them into percentages. For a deeper treatment, visit the complete guide to the three RTT exam domains.
Domain 1: Patient Care (46 scored questions)
This domain covers how therapists interact with patients and manage the information surrounding their care.
- Patient Interactions and Management (29): communication, assessment, and managing patients through a course of treatment.
- Patient and Medical Record Management (17): documentation and record-keeping tied to the treatment process.
Domain 2: Safety (51 scored questions)
Safety blends the science behind radiation therapy with the practical safeguards that protect patients and staff.
- Radiation Physics and Radiobiology (21): how radiation interacts with matter and with living tissue.
- Radiation Protection, Equipment Operation, and Quality Assurance (30): protection practices, operating treatment equipment, and quality-control checks.
Domain 3: Procedures (103 scored questions)
The largest domain, covering about half of all scored questions by count. It is where the day-to-day work of a radiation therapist lives.
- Treatment Sites and Tumors (26): anatomy and disease sites you will treat.
- Treatment Volume Localization (18): simulation and defining where treatment is directed.
- Prescription and Dose Calculation (24): turning a prescription into delivered dose.
- Treatments (35): delivering treatment accurately and consistently.
Scope Boundaries Worth Knowing
The content specifications set deliberate limits that can save you study time:
- SI units are primary.
- Brachytherapy coverage is limited to basic common-use, surrounding-tissue-dose, and radiation-protection concepts, not detailed procedures or isotope characteristics.
- Staging is limited to basic concepts rather than site-specific staging.
- Specific CPT codes are excluded.
Key Takeaway
Procedures alone accounts for 103 of 200 scored questions, and Treatments (35) is the single largest subtopic. Weakness in this domain is hard to offset elsewhere, so give it the most study time.
Scoring, Attempts, and Pass-Rate Context
The passing score is 75 on ARRT's 1-99 scaled-score range. That is a scaled score, not 75% of questions answered correctly. A revised examination cut-score standard took effect February 1, 2025, while the reported passing score remains 75 scaled. Read more in our breakdown of the RTT passing score.
Candidates get three examination attempts within three years of the opening of the initial examination window. This is separate from the application deadline described earlier.
For context, the ARRT Annual Exam Report for 2025 lists a first-time candidate pass rate of 77.1% (n=958). That is one year's figure for one group of candidates, so treat it as a reference point rather than a forecast. Our RTT pass rate analysis discusses how to interpret it responsibly.
Fees and Registration Mechanics
ARRT fees for the Radiation Therapy primary pathway are straightforward:
| Item | Amount (USD) |
|---|---|
| Initial application | $225 |
| Examination reapplication | $200 |
| Annual renewal | $65 (regardless of the number of ARRT credentials held) |
You apply through ARRT and then schedule your appointment with Pearson VUE. Keep in mind that the initial application must be submitted within three years of program completion. For the full financial picture, including prep costs, see the RTT certification cost breakdown, and for timing details, our guide to RTT exam dates and scheduling.
Scheduling Your Prep Around the Domains
Generic study advice matters less than allocating time where the points are. Using the official counts, here is one way to sequence an eight-week plan, with Procedures getting the lion's share of attention. For a longer roadmap, see our RTT study guide.
Safety foundations
- Radiation physics and radiobiology (21 questions) underpin everything else, so start here.
- Move to radiation protection, equipment operation, and quality assurance (30 questions).
Procedures, the heavy lifter
- Treatment sites and tumors, then volume localization.
- Prescription and dose calculation, practicing on the on-screen calculator.
- Treatments, the largest single subtopic at 35 questions.
Patient Care
- Patient interactions and management (29), plus medical record management (17).
Integrated review
- Mixed practice sets under timed conditions, then a one-page review with the RTT cheat sheet.
Physics comes first because dose calculation and treatment delivery questions in Procedures assume you already understand it. Once you have a baseline, take a few questions from our RTT practice test to see which domains need extra time.
After You Pass: Renewal, CE, and CQR
Earning the credential is the start of a maintenance cycle:
- Annual renewal of certification and registration at $65, no matter how many ARRT credentials you hold.
- Ethics compliance on a continuing basis.
- 24 approved continuing education credits per two-year biennium, counted per biennium rather than per credential.
- Continuing Qualifications Requirements (CQR) every 10 years for credentials earned on or after January 1, 2011. 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.
Where Radiation Therapists Work
Radiation therapists work in settings that deliver radiation treatment, commonly hospital-based cancer centers, freestanding radiation oncology clinics, and academic medical centers. The role is hands-on and patient-facing: you position patients, operate treatment equipment, verify setups, and monitor patients across what may be many weeks of treatment. That daily patient contact is why Patient Care is a full exam domain rather than an afterthought.
If you are weighing the career side, our guides on RTT jobs, the RTT salary guide, and whether the RTT certification is worth it go deeper on employment and earning potential. For help with the learning side, see RTT training.
Frequently Asked Questions
RTT stands for Registered Technologist - Radiation Therapy. It refers to the ARRT's Radiation Therapy (T) credential, earned through the primary eligibility pathway. RTT is this site's abbreviation, not ARRT's official discipline designation.
No. An existing Radiography credential is not a universal prerequisite. You qualify through the primary pathway by holding an associate degree or higher, completing an ARRT-verified radiation therapy program, and meeting the ethics requirements.
The exam has 230 questions: 200 scored and 30 unscored pilot questions. You get 230 minutes of answering time within a 250-minute appointment that also covers the tutorial, nondisclosure agreement, and survey.
No. The passing score of 75 is on ARRT's 1-99 scaled-score range. Scaled scores reflect the exam's cut-score standard rather than a raw percentage of questions answered correctly.
You have three attempts within three years of the opening of your initial examination window. Each reapplication costs $200. This three-year attempt period is separate from the deadline to submit your initial application after completing your program.