Types of Medical Imaging

Sonographer looking at medical imaging pictures

Radiology is an ever-changing, dynamic field of medicine that provides a wide range of career opportunities. As a diagnostic imaging technologist, you will be part of a life-saving team that diagnoses and treats a vast array of medical conditions. From the most common imaging test ordered, the chest x-ray, to a life-saving diagnosis of an unborn baby’s rare condition, radiologic professions are both challenging and rewarding. Some sub-specialties allow for a broad base of exposure to imaging, while others have a narrower, specific skill set.

There are multiple imaging modalities you can consider if you want a career in radiology, including x-ray, CT, MRI, nuclear medicine and ultrasound. Each of these paths offers different options for levels of education, from certifications to master’s degrees. Because there are so many specialties and subspecialties within radiology, we wanted to give you a rundown of some of the terms most commonly associated with diagnostic medicine education and careers.

What is Diagnostic Imaging?

  • Diagnostic Imaging – The field of using technology that produces images of body parts to diagnose illnesses.
  • Radiology – The field of using technology to produce images of body parts to diagnose illnesses. Used interchangeably with “diagnostic imaging.”
  • Anatomy – The medical terms for the individual parts of the body.
  • Pathology – Abnormal functions of the body. Radiologists use technology to determine pathology.

Radiology Terminology

Radiology is a field of medicine that includes several different types of imaging, each with its own set of technology and equipment, in order to provide diagnosis or treatment of medical conditions. The common types of radiology are x-ray, CT, MRI, nuclear medicine and ultrasound. Each of these is discussed in more detail below.

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  • Radiologist – Medical doctors that specialize in reading and interpreting diseases and injuries with the use of different modalities of medical imaging.
  • Radiology Technician – A term that may be used for someone who performs medical imaging in more than one specialty.

Visit our radiology page for more information on radiology education and careers.

Sonography Terminology

Sonography, or ultrasound, is performed by a sonographer (or “ultrasound technologist”) and uses sound waves to produce images of different parts of anatomy. Sonographers often work in a sub-specialty of sonography including general abdomen, vascular, cardiac, or obstetrics.

  • Sonographer – Someone who performs an ultrasound. Used interchangeably with ultrasound technologist and ultrasound technician.
  • Sonography – Taking and interpreting images of body structures taken by producing soundwaves that are returned to the transducer.
  • Ultrasound Technologist – Someone who performs an ultrasound. Used interchangeably with sonographer and ultrasound technician.
  • Ultrasound Technician – Someone who performs an ultrasound. Used interchangeably with sonographer and ultrasound technologist.
  • Probe – The handheld “camera” used by sonographer so transmit the sound waves into the appropriate area of the body. Used interchangeably with transducer.
  • Transducer – The handheld “camera” used by sonographer so transmit the sound waves into the appropriate area of the body. Used interchangeably with probe.

If you want to learn more about sonography education and careers, visit our sonography page.

X-Ray Terminology

X-rays are obtained by technologists or technicians that use an x-ray machine to obtain images of anatomy, most commonly bone. In this quick and painless procedure, bone and metal are both shown as white, making them easy to evaluate.

  • X-Ray Technologist – Someone who performs x-rays for interpretation by a radiologist. Used interchangeably with x-ray technician.
  • Radiography Technician – Someone who performs x-rays. Used interchangeably with x-ray technologist or x-ray technician.
  • Radiograph – An x-ray film with an anatomical image.

MRI Terminology

Magnetic resonance imaging, or MRI, is often used to evaluate the soft tissue structures, such as the brain, or identify tumors within the body. MRI technologists are unique in the radiology field in that the machines they operate use magnets and radio waves rather than radiation.

  • MRI – MRI stands for Magnetic Resonance Imaging. Images of the body are produced using magnetic and radio waves.
  • MRI Technologist – Someone who performs MRI exams for interpretation by a radiologist. Used interchangeably with MRI technician.

Learn more about MRI professions and degrees.

CT Terminology

Computed tomography – Also known as CT, computed tomography holds a distinctive place in radiology, as it is capable of images all types of tissue, including soft tissue, bone and vasculature. The computerized manipulation of the special x-rays in CT allow for three-dimensional evaluation of anatomy.

  • CT – CT stands for computed tomography, which is a computerized form of x-ray used for more detailed evaluation of anatomy or pathology.
  • CT Technologist – Someone who performs CT exams. Used interchangeably with CT technician.

Nuclear Medicine Terminology

Nuclear medicine technologists utilize special medicine to allow a person’s anatomy to be radioactive for a short time to better take images of it. Unlike other types of radiology, the focus of nuclear medicine is not just on imaging the anatomy, but on evaluating its function. Nuclear medicine can also be used to treat some conditions.

  • Nuclear medicine – A branch of medical imaging that utilizes radioactive material in order to diagnose and treat disease.
  • Radiopharmaceuticals – Radioactive medication given to patient to allow their anatomy to be radioactive for a short time.
  • Gamma camera – A camera used to receive the radiation emitted from the patient’s body during a nuclear medicine exam.
  • PET Scan – PET stands for Positron Emission Topography. It is one of the most common types of nuclear medicine scans.


A sub-specialty is a more focused area of one of the imaging types included under the umbrella of radiology (ultrasound, CT, MRI, X-Ray, nuclear medicine). Of the main types of radiology, ultrasound has the most sub-specialties. If you work within a sub-specialty, you will focus on the images specific to that specialty and may not do any imaging of the areas included in the other sub-specialties.

  • Vascular – Specific imaging related to the blood flow throughout the body, focusing on the applicable individual veins and arteries needed for the type of exam being performed.
  • Cardiac – Specific imaging related to the heart. Focusing on all aspects of the heart and the blood flow through and around the heart. There are three specialties within cardiac and some people may be able to work within more than one, as the training often overlaps.
    • Adult
    • Pediatric
    • Fetal
  • General Abdomen – Imaging specific to the internal organs not included in other specialties. This includes liver, kidneys, pancreas, gallbladder, thyroid, scrotum, and female pelvic. This specialty is often combined with vascular.
  • OBGYN – General or low-risk pregnancy.
  • MFM – Maternal Fetal Medicine – high risk pregnancy.
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Radiology Certification Terminology

  • Board – Exam one must pass in order to become credentialed in a specialty. Used interchangeably with registry.
  • ARDMS – American Registry of Diagnostic Medical Sonography – credentialing body of registered sonographers.
  • SPI – Sonography Principals and Instrumentation – The board exam that focuses on physics of ultrasound and instrumentation that must be passed prior to application for any other registry with the ARDMS.
  • RVT – Registered Vascular Technologist – The credential obtained after passing the board for vascular ultrasound.
  • DCS – Diagnostic Cardiac Sonographer – The credential obtained after passing the ultrasound registry for adult or fetal cardiology.
  • RDMS – Registered Diagnostic Medical Sonographer – The credential obtained after passing an ultrasound registry board in the following subspecialties:
    • OBGYN
    • Abdomen
    • Breast
    • Fetal Echo
  • ARRT – American Registry of Radiologic Technologists – Credentialing body of registered radiologic technologists in multiple subspecialties.
  • RT – Registered technologist – Credentials held by x-ray technologists.
  • MR – Credential obtained after becoming certified in MRI.
  • CT – The credential obtained after becoming certified in CT.
  • NMTCB – Nuclear Medicine Technology Certification Board – Considered the premium credentialing board for nuclear medicine.

About the Author:

Lyndsay Fundell has a worked as a perinatal sonographer supervisor in an academic health system since June 2011. She has a degree in diagnostic medical ultrasound and a master’s in healthcare administration.