What is Radiology?

The Merriam-Webster online dictionary defines radiology as “a branch of medicine that uses some forms of radiation (such as X-rays) to diagnose and treat disease.” This website focuses on radiation used to diagnose disease1. More accurately, I will talk about diagnostic imaging, which includes imaging modalities that use radiation—X-ray, CT, Nuclear Medicine, Mammography, PET—and those that do not—MRI and ultrasound. A diagnostic radiologist, usually just called a radiologist, is trained to oversee and interpret diagnostic imaging.

A (somewhat) brief history of radiology

Can you guess what the very first Nobel Prize in physics was awarded for? Hoverboards? Dippin’ Dots? Dyson vacuums? Those with a sharp intuition may sense it has something to do with radiology, and you would be right!

Wilhelm Conrad Röntgen, a magnificently-bearded German physicist—who would not be out of place behind the counter at Starbucks—was honored with the Nobel Prize in 1901 “in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him.”2 Some of you are understandably confused; I thought they were called X-rays, you say, not “Röntgen rays”. It turns out both names are correct. Röntgen coined the term “X-ray” because he did not know what the heck they were, but X-rays were historically also known as Röntgen rays. One of the major professional radiology societies, ARRS, stands for American Röntgen Ray Society. In the end, use of the term “X-ray” almost certainly came down to ease of use. Imagine the atrocities in pronunciation that would occur if we called them “röntgenograms.”

Dude, where's my Röntgen ray?
Dude, where’s my Röntgen ray?

Röntgen’s experiments involved cathode ray tubes, like those in old-school TVs. In 1895, he discovered that when all visible light was blocked from these tubes, they still emitted a magical “X-ray” that made a receptive substance across the room glow when struck by this radiation. Subsequently, he created a type of picture on a photographic plate by “shining” X-rays through different materials. The first ever X-ray was the hand of Röntgen’s wife Anna, and the field of radiology was born.

He liked and, and he put a ring on it
He liked and, and he put a ring on it

I get a little misty-eyed whenever I see a hand X-ray with a ring on it, thinking about Mr. Röntgen irradiating his wife all those years ago.

X-rays—called radiographs by those in the biz—were pretty much the only game in town for the next 50 years. Mammography, which amounts to X-rays of the breast, came into use in the 1930s. In 1946, the field of nuclear medicine was (arguably) born when radioactive iodine was administered to treat thyroid cancer. Later, specialized cameras allowed the visualization of these radioactive substances, including PET scanners developed in the 1970s.

Ultrasound was first utilized for medical imaging in the 1940s, and new ultrasound technologies have led us to the modern “4-D” ultrasound machines of today. Computed tomography (CT) scanning was first described in 1972, and has evolved into a critical imaging tool, particularly in the setting of trauma and acute illness. Magnetic resonance imaging (MRI), also developed in the 1970s, has become widespread and in many ways complementary to CT scanning.

Radiology today

Much has transpired in the field of radiology since Dr. Röntgen took those first X-rays over 100 years ago. Each imaging modality—CT, MRI, etc.— is immensely complex, a world unto itself, and deserves further exploration via future posts to come. Radiology plays a key and ever-increasing role in diagnosing disease, and—with advancements in imaging technology, computers, and digital communications—occupies a critical position in modern health care.

Next, find out what a radiologist does all day.


  1. Radiation oncology deals with using radiation to treat disease, usually cancer. It is a whole different ballgame. As a diagnostic radiologist, I received essentially no training in radiation oncology, and have no special expertise to discuss issues related to this field. Perhaps, one day, there will be a Neighborhood Radiation Oncologist somewhere out there.
  2. “Wilhelm Conrad Röntgen – Facts”. Nobelprize.org. Nobel Media AB 2014. Web. 28 Jan 2016. <http://www.nobelprize.org/nobel_prizes/physics/laureates/1901/rontgen-facts.html>


Nobel Lectures, Physics 1901-1921, Elsevier Publishing Company, Amsterdam, 1967