What Is A RTT?

What the Title Actually Means

On this site, RTT stands for Registered Technologist - Radiation Therapy. It is the credential held by radiation therapists: the professionals who deliver prescribed doses of ionizing radiation to patients, most often to treat cancer. If you have searched "what is a RTT" and landed on a page about network latency or another certification that shares the letters, you are in the wrong place. Everything here concerns the radiation therapy credential.

A small clarification on terminology. The ARRT's official name for the discipline is simply Radiation Therapy (T). "RTT" is the abbreviation this site uses for the credential, not a designation the ARRT assigns. If you want to see how the ARRT itself asks people to list credentials after their names, its credential-designation page is the authoritative reference. For broader orientation on the abbreviation, see our companion articles What Does RTT Stand For? and RTT Meaning.

Who Issues the Credential

The credential is issued by the American Registry of Radiologic Technologists (ARRT), the same organization that certifies radiographers, nuclear medicine technologists, sonographers and several other imaging and therapy professionals. The ARRT sets the eligibility rules, writes the examination content specifications, determines the scoring standard and administers ongoing maintenance requirements.

The examination itself is delivered through Pearson VUE test centers. That matters for planning: you will sit in a proctored, secure testing environment rather than taking the exam at home. The practical consequences, including calculator rules and check-in procedures, are covered below.

What a Radiation Therapist Does

The credential makes more sense once you understand the work behind it. A radiation therapist is a member of the oncology team who works alongside radiation oncologists, medical physicists, dosimetrists and nurses. Typical responsibilities map closely to the exam's content areas:

• Interacting with patients who are often frightened, fatigued or in pain, explaining procedures, monitoring side effects and recognizing when a patient needs medical attention.
• Positioning and immobilizing patients precisely, often with custom devices, so treatment is delivered to the intended volume session after session.
• Operating treatment delivery equipment, including verifying the plan, checking imaging for alignment and delivering the prescribed dose.
• Participating in simulation, the planning session where the treatment area is localized and reference marks and immobilization are established.
• Performing quality assurance checks and following radiation protection principles for patients, colleagues and the public.
• Maintaining accurate records, since the treatment chart is a legal and clinical document where errors have serious consequences.

Because the daily work involves repeated, high-stakes accuracy, the exam leans heavily on applied procedural knowledge rather than abstract theory.

Who Hires Registered Technologists in Radiation Therapy

Radiation therapists work wherever external-beam radiation and related treatments are delivered. Common employers include:

• Hospital radiation oncology departments, both community hospitals and large academic medical centers.
• Freestanding cancer centers and comprehensive cancer institutes.
• Physician-owned or network-affiliated radiation oncology practices operating outpatient treatment facilities.
• University health systems, where therapists may also take on student supervision, research protocols or advanced technique roles.

Employers generally treat the ARRT credential as the baseline qualification, and many states link licensure or practice authorization to it. Because requirements vary by state, check your state's rules separately. For a closer look at the job market and the kinds of positions available, read RTT Jobs. If you are weighing earnings, the RTT Salary Guide 2026 and the RTT certification ROI analysis go deeper. We avoid quoting specific pay figures here because they vary by region, employer and experience.

How You Become Eligible

This is where the credential is most distinctive. Eligibility under the ARRT's primary pathway has three pillars, and all must be satisfied.

Education

You need an associate degree or higher from an ARRT-recognized accredited institution. The degree can be in any major, but it must be conferred before you sit for the examination. You must also complete an ARRT-verified radiation therapy educational program, including its didactic coursework and clinical competencies.

Clinical competency

The clinical requirements are specific and demanding. They 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, plus 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

Your program director or designee must verify these competencies through in-person direct observation. Remote or virtual observation is not accepted.

Ethics

You must comply with the ARRT's ethics requirements, which include disclosure of certain legal and disciplinary matters. Review them before you apply, since certain histories require advance review.

For the full eligibility picture, see RTT Requirements 2026 and RTT Training.

How the Exam Is Built

The examination is computer-based and closed book. Here is the structure at a glance:

Two details deserve attention. First, the 30 unscored pilot questions are indistinguishable from scored ones, so treat every item seriously. Second, because you must answer each question before moving forward, you cannot skip and return to a blank. Use the flag feature instead: commit to a best answer, flag it, and revisit if time allows. Learn more about difficulty and what makes the questions challenging in How Hard Is the RTT Exam?

The Three Content Areas in Detail

The ARRT organizes the exam into three major content categories. These come from the official content specifications, and the scored-question counts below are the official allocations. The controlling document for exams through January 31, 2027 is the Radiation Therapy Examination Content Specifications (board approved January 2021, effective January 1, 2022). A separate 2027 specification takes effect February 1, 2027; do not mix it into your 2026 preparation.

Several scope boundaries help you avoid wasting study time. Brachytherapy coverage is limited to basic common-use concepts, surrounding-tissue dose and radiation protection, not detailed procedures or isotope characteristics. Staging is limited to basic concepts rather than site-specific staging systems. Specific CPT codes are excluded.

For a domain-by-domain walk-through, see RTT Exam Domains 2026, and for a quick refresher before test day, the RTT Cheat Sheet.

Scoring, Attempts and Fees

The score you need

The passing score is 75 on the ARRT's 1-99 scaled-score range. This is a scaled score, not a percentage of questions answered correctly. Scaling accounts for differences in difficulty between exam forms, so the raw number of correct answers needed can differ slightly between forms. A revised cut-score standard took effect February 1, 2025, while the reported passing score remains 75 scaled. Details are in RTT Passing Score 2026.

Pass rate

According to the ARRT Annual Exam Report for 2025, 77.1% of first-time candidates passed in 2025 (n=958). Treat this as a snapshot of one year rather than a guarantee, and see RTT Pass Rate 2026 for context.

Attempts

You have three examination attempts within three years of the opening of your initial examination window. Plan your first attempt as if it will be your only one.

Fees

Always confirm current amounts on the ARRT fee page before paying, and see RTT Certification Cost 2026 for the full breakdown. Scheduling windows and deadlines are covered in RTT Exam Dates 2026.

Keeping the Credential Active

Passing the exam is the beginning of a maintenance cycle, not the end. To keep the credential and your registration current, you need to:

• Renew annually for $65, which covers all of your ARRT credentials together.
• Stay in compliance with ethics requirements, including reporting relevant events.
• Earn 24 approved continuing education credits each two-year biennium. This is per biennium, not per credential, so holding multiple ARRT credentials does not multiply the total.
• Complete Continuing Qualifications Requirements (CQR) every 10 years if your credential was earned on or after January 1, 2011. CQR involves a professional profile, a structured self-assessment and any prescribed continuing education. The ARRT also allows you to accept the maximum CQR CE prescription instead of taking the self-assessment.

Think of the exam as a licensing gate and CE as the long game. Choosing credits that reinforce your clinical specialty keeps your skills sharp and makes the requirement feel like professional development rather than paperwork.

Sequencing Your Preparation by Domain

You do not need an elaborate system. Tie your schedule to the exam's weighting and to the way the content builds on itself. Here is one reasonable sequence for a candidate with several weeks to prepare:

Why this order? Physics and radiobiology explain why techniques work, which makes the large Procedures domain easier to retain. Patient Care is lighter in raw question count and more intuitive for people with clinical experience, so it fits well as a final integration week. Adjust to your own weaknesses; a candidate strong in clinical work but rusty on dose calculation should shift time toward the latter. For a fuller plan, read the RTT Study Guide 2026, and use our practice tests to find your weak spots early. When you are ready to measure yourself under exam-like conditions, take a full-length practice exam and review every miss against the content areas above.

Frequently Asked Questions