50 Fun Facts About Radiology

Who discovered X-rays in 1895?

He was experimenting with vacuum tubes at the University of Würzburg on the evening of 8 November 1895.

Why did Röntgen call his discovery 'X'-rays?

He ate and slept in his lab for weeks investigating them; many languages still call them Röntgen rays.

Whose hand appears in the famous first X-ray radiograph, taken about six weeks after the discovery?

On seeing her skeleton she is said to have exclaimed 'I have seen my death!'

Röntgen won which award in 1901 for discovering X-rays?

Like the Curies, he refused to patent his discovery so that everyone could benefit from it.

World Radiography Day is celebrated on which date?

It marks the anniversary of the 1895 discovery; the International Society of Radiographers has celebrated it since 2007.

Which two men shared the 1979 Nobel Prize in Physiology or Medicine for developing the CT scanner?

Cormack, a Tufts physicist, had never earned a doctorate in any scientific field.

At which company did Godfrey Hounsfield build the first CT scanner?

The first production machines were simply called EMI scanners.

Where and when was the first clinical CT scan performed on a patient?

The patient had a cerebral cyst; Hounsfield had tested his prototype on a preserved brain, a butcher's cow brain and himself.

On the Hounsfield scale used in CT, what value is assigned to distilled water?

Air is -1000; each unit is a 0.1 percent change in the attenuation of water.

The word tomography comes from Greek words meaning what?

Tome is slice, graphein is to write.

Which imaging method uses no ionising radiation at all, unlike CT and PET?

It relies on the magnetic spin of hydrogen protons responding to radio-frequency pulses inside a strong magnet.

Who shared the 2003 Nobel Prize in Physiology or Medicine for discoveries concerning MRI?

Mansfield developed echo-planar imaging, the technique behind fast MRI.

Who performed the first full-body MRI scan of a human being, in 1977?

He had proposed an MR body scanner in 1969 and was famously left out of the 2003 Nobel Prize.

In what unit is the field strength of an MRI magnet measured?

Most clinical systems run at 1.5 T; 3 T scanners give better soft-tissue images and research systems reach 7 T.

Which nuclei does conventional MRI image, because they are so abundant in the body's water and fat?

Their nuclear spins resonate with the radio-frequency pulse and emit a signal as they relax.

Marie Curie's mobile X-ray units for First World War field hospitals were nicknamed what?

She learned anatomy and car mechanics for the job and was helped by her 17-year-old daughter Irène.

What killed Marie Curie in 1934, likely a result of her radiation exposure?

She died at a sanatorium in the French Alps aged 66.

Which Glasgow professor pioneered obstetric ultrasound, with a landmark Lancet paper in June 1958?

He worked with obstetrician John MacVicar and engineer Tom Brown of Kelvin & Hughes.

Who probably first imaged the human body with ultrasound, outlining the brain's ventricles in 1941?

The Austrian neurologist worked with his physicist brother Friedrich.

The ultrasound technique for measuring blood flow is named after which 19th-century physicist?

He described the frequency shift of waves from a moving source in 1842.

Superficial structures like the thyroid are scanned at higher ultrasound frequencies. Roughly what range?

Deep organs such as the liver use lower frequencies, 1 to 6 MHz, trading resolution for penetration.

His assistant became one of the first radiation deaths. Which inventor built an early commercial fluoroscope?

Glassblower Clarence Dally lost his left hand and four fingers of his right before dying in 1904.

What is the most common radiographic examination in medicine?

It shows heart, lungs, airways and bones in a single exposure.

Which two elements are the classic positive contrast agents in X-ray imaging?

Air and carbon dioxide are used as negative agents; gadolinium is the MRI contrast.

Which Portuguese neurologist developed cerebral angiography in 1927?

His colleague Reynaldo dos Santos performed the first aortogram in Lisbon two years later.

Who invented angioplasty and the catheter-delivered stent, the 'father of interventional radiology'?

He described angioplasty in 1964; it was first used for peripheral arterial disease.

What is the most commonly used medical radioisotope in the world?

Its six-hour half-life and 140 keV gamma rays make it ideal; it is 'milked' from molybdenum-99 generators.

What is the half-life of the metastable isotope used in most nuclear medicine scans?

Roughly 94 percent of it decays within 24 hours, keeping patient dose low.

Which glucose analogue is the workhorse radiotracer of PET scanning in oncology?

Cancer cells gobble up the sugar mimic, lighting up on the scan.

In PET, what happens when the emitted positron meets an electron?

Detectors on opposite sides of the ring catch the pair, which is how the scanner locates the source.

The SI unit of absorbed radiation dose, one joule per kilogram, is named after which physicist?

The sievert, for biological effect, honours Swedish medical physicist Rolf Sievert instead.

Per the ICRP, one sievert raises the lifetime chance of fatal cancer by roughly how much?

That figure rests on the disputed linear no-threshold model.

What does the radiation-safety acronym ALARA stand for?

The British version, ALARP, swaps 'achievable' for 'practicable'.

Which German surgeon founded mammography in 1913 by X-raying 3,000 mastectomy specimens?

He was the first to spot microcalcifications on film.

Which US body, founded in 1915, hosts the world's largest medical imaging conference in Chicago?

RSNA also publishes the journal Radiology and RadioGraphics.

In an imaging department, who is the medical doctor who interprets the scans and writes the report?

For medicine's first three decades, from 1897 into the 1930s, nobody distinguished the two roles.

Since the 1950s, what device in most fluoroscopes brightens the picture and sends it to a remote screen?

Fluoroscopy shows moving X-ray images in real time, useful for swallowing studies and catheter guidance.

Which of these is the classic protective garment worn during dental and fluoroscopic X-rays?

Thyroid shields and lead gloves round out the personal kit; rooms are often lined with lead-backed drywall.

Röntgen made a better public demonstration radiograph in 1896 using the hand of which anatomist friend?

Kölliker proposed on the spot that the new rays be called Röntgen rays.

Where in the electromagnetic spectrum does X-radiation sit?

They are high-energy radiation with wavelengths shorter than UV and longer than gamma.

Molybdenum-99, the parent isotope 'milked' in hospital generators, has a half-life of how long?

The generator is nicknamed a 'moly cow' because technetium is 'milked' from it.

At which university's Physical Institute was Röntgen working when he discovered X-rays in 1895?

He was testing Crookes-Hittorf tubes under black cardboard when a nearby barium platinocyanide screen began to glow.

Why was the teenage Röntgen expelled from Utrecht Technical School in 1865?

Without a diploma he could only audit university courses, so he moved to Switzerland and passed the Zurich polytechnic's entrance exam.

What was the very first radiographic image Röntgen saw, glowing on his fluorescent screen?

He was moving a piece of lead into the beam when his own flickering bones appeared on the barium platinocyanide screen.

What was the title of Röntgen's original X-ray paper, published on 28 December 1895?

He published only three papers on X-rays in all, and shared the Royal Society's Rumford Medal with Philipp Lenard in 1896.

Which American university had Röntgen agreed to join before the First World War kept him in Munich?

He had family in Iowa and had already bought his transatlantic tickets.

Why did Röntgen, like the Curies, refuse to patent his discovery?

Too shy to speak in public, he also declined to give a lecture when he received the first Nobel Prize in Physics.

At what field strength do the majority of clinical MRI systems operate?

Commercial systems range from 0.2 to 7 T, and research whole-body machines run at 9.4 T and beyond.

What name did Paul Lauterbur give his 1973 method of using magnetic field gradients to make a 2-D NMR scan?

He demonstrated it by imaging the proton density of two tubes of water in an artificial sample.

What is the common name for the dominant type of CT scanner, in which the whole X-ray tube spins around the patient?

Such scanners lead the market because they have been made longer and cost less to build and buy, despite their bulk and inertia.