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For more than a century a vital tool for doctors to use in diagnosing a wide range of medical conditions has been X-ray photography.

Today is World Radiography Day, held each year on November 7th to mark the anniversary of the day in 1895 when German engineer and physicist Wilhem Röntgen (pictured below) first detected X-rays. As well as recognising the significant contribution of his milestone discovery to modern healthcare, the annual event is also used to promote radiography as a career and raise public awareness of diagnostic imaging and radiation therapy.

Before X-rays, the only ways for doctors to diagnose what was going on inside the human body was by trying to interpret outwards symptoms or, as a last resort, carrying out exploratory surgery. In days when infection was rife and antibiotics to fight it did not exist, such surgery routinely carried a life-threatening risk.

These days we risk taking X-rays for granted, but the science of using and interpreting them (radiography) gave doctors the precious gift of being able to see inside a patient’s body without picking up a scalpel. It was a truly revolutionary development in modern medicine and one which continues to save countless lives every day.

Röntgen’s discovery of electromagnetic radiation in a wavelength which he later termed ‘X-rays’ earned him the very first Nobel Prize in Physics, presented in 1901. More than a century later, in 2004, the International Union of Pure and Applied Chemistry named a newly-discovered radioactive element “roentgenium” in honour of Röntgen’s contribution to science and medicine.

As with the many scientific discoveries, Röntgen’s was made almost by accident. He had been investigating what happens when an electrical discharge is passed through various types of vacuum tube equipment when he noticed that the invisible cathode rays caused a fluorescent effect on a small cardboard screen painted with barium. He had only put the screen in the equipment to protect a piece of aluminium behind it.

Pursuing this interesting effect in the late afternoon of November 8th, 1895, he carried out further experiments in a darkened room. He then realised that some kind of electromagnetic ray was going right through his test equipment and causing a spare barium-painted cardboard screen to fluoresce several feet away, across his laboratory. Speculating that a new kind of ray might be responsible, he continued refining his experiments and over the next few weeks he ate and slept in his lab, working mostly in secret.

Because he didn’t know what the new rays were, he temporarily termed them “X-rays”, because “X” was the mathematical symbol used for an unknown quantity. He soon discovered that his X-rays could pass through various types of solid matter and, while trying to find out which materials could stop the rays, he discovered they could be used to create an image of what they had passed through.

Almost two weeks after his initial discovery, Röntgen took the very first ‘X-ray picture’ of his wife Anna Bertha’s hand. When she saw her skeleton she exclaimed in alarm: “I have seen my death!”

More weeks of experimenting, refining and meticulously writing up his work followed until, on December 28th, 1895, Röntgen published a paper entitled “On a New Kind of Rays”, revealing his remarkable discovery to the wider scientific world. It met with immediate acclaim, other researchers then duplicating and expanding his experiments and Röntgen himself awarded an honorary Doctor of Medicine degree from the University of Würzburg.

He went on to publish two more highly influential papers on his discovery and is now widely recognised as the father of diagnostic radiology. Today’s celebration of World Radiography Day also recognises his remarkable discoveries and the major advances they have enabled in modern diagnostic medicine.

His X-rays – the name seemed to stick – still play a key role in the diagnosis of a huge range of conditions and, in doing so, have saved millions of lives.

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