Radiologic Technologist Credentials 2026: What R.T.(R) Means

What do radiologic technologist credentials like R.T.(R) mean?

ARRT is the American Registry of Radiologic Technologists. Its guide to listing credentials says to write your full name, a comma, then R.T., the discipline abbreviations in brackets and (ARRT) at the end, with no spaces inside the brackets. A radiographer writes Pat Smith, R.T.(R)(ARRT). Someone with Radiography, computed tomography (CT) and magnetic resonance imaging (MRI) credentials writes Pat Smith, R.T.(R)(CT)(MR)(ARRT). ARRT says most people list them in the order they earned them. An R.R.A. lists that first: Pat Smith, R.R.A., R.T.(R)(ARRT).

ARRT: How to list your credentials ↗

ARRT disciplines and their letters

Primary disciplines are a first credential, earned through an ARRT-approved program. Postprimary ones are added on top of a supporting credential.

Discipline	Letters	Pathway
Radiography	R	Primary
Nuclear Medicine Technology	N	Primary
Radiation Therapy	T	Primary
Sonography	S	Primary
Magnetic Resonance Imaging	MR	Primary or postprimary
Vascular Sonography	VS	Primary or postprimary
Computed Tomography	CT	Postprimary
Mammography	M	Postprimary
Bone Densitometry	BD	Postprimary
Cardiac Interventional Radiography	CI	Postprimary
Vascular Interventional Radiography	VI	Postprimary
Breast Sonography	BS	Postprimary

The other two of the 14, Quality Management (QM) and Cardiovascular Interventional Radiography (CV), are no longer issued, though people who hold them can keep them. Radiography is the supporting credential for every postprimary discipline and for the R.R.A. Holders of a Nuclear Medicine Technology Certification Board (NMTCB) or American Registry for Diagnostic Medical Sonography (ARDMS) credential can use it as the supporting credential for some disciplines.

ARRT: R.T. credential options ↗ARRT CT certification →ARRT MRI certification →

ARRT sonography and mammography

Sonography is a primary discipline with its own program. Its exam is the longest ARRT gives: 360 scored and 40 pilot questions in two sessions, with a 30-minute break between them. It also has an extra passing rule for two sections, set out on the pass rate page.

Mammography is postprimary, with Radiography as the supporting credential. Like CT, it needs structured education and documented clinical experience before you apply. Breast Sonography needs both Radiography and Mammography, or a Sonography or Vascular Sonography credential.

ARRT: Supporting category requirements ↗Sonography’s passing rule and pass rates →

How do I become a radiologist assistant?

The Registered Radiologist Assistant (R.R.A.) is ARRT’s advanced practice credential. R.R.A.s are radiographers who have completed an extra radiologist assistant program and passed ARRT’s exam, and they perform some procedures under a radiologist’s supervision. You need an ARRT credential in Radiography, a master’s degree or higher and an ARRT-recognized radiologist assistant program. A radiologist is a physician; that’s a different career and not an ARRT credential.

ARRT: Registered Radiologist Assistant ↗R.R.A. renewal and continuing education →

The Imaging Assistant credential

ARRT describes the Imaging Assistant, Magnetic Resonance, I.A.(MR), as an entry point into medical imaging: you must be 18 or older with a high school diploma or General Educational Development (GED) credential, rather than an associate degree. To pass its exam you need a 75 overall and at least 7.5 in the MRI screening and safety section.

ARRT: Imaging Assistant requirements ↗The steps to an R.T. credential →

Sources: ARRT and 8 more. Checked October 2026.