X-rays for the benefit of all

Many innovations that have transformed everyday life and industry are the result of years of development and the persistent work of a small number of entrepreneurs. Yet some discoveries emerge from unexpected observations made in the course of scientific research. This is also true of the radiation that still bears the name of its discoverer today.

Making the Invisible Visible

Exactly how Wilhelm Conrad Röntgen discovered the new type of radiation is no longer fully known. The scientific records that might have provided further insight were destroyed after his death. According to historical accounts, on the evening of November 8, 1895, Röntgen was conducting experiments when he noticed that a fluorescent screen some distance from the tube which was covered began to glow, and suddenly the physicist is said to have seen the bones of his own hand. When Röntgen was later asked what he had thought when he made his discovery which he called »X-rays«, he reportedly replied: »I did not think. I investigated.«

Wilhelm Conrad Röntgen: From School Dropout to Professor

The fact that Röntgen was able to pursue an academic career was far from a given, as he did not have a high school diploma: In 1863, he had to leave the Technical School in Utrecht without graduating after being falsely accused of a disciplinary offense. A few years later, however, he was admitted to the Swiss Federal Polytechnic in Zurich. There, he studied mechanical engineering and graduated as a mechanical engineer in 1868. He subsequently turned to physics under the influence of his mentor, August Kundt.

After academic positions in Strasbourg and Gießen, Röntgen eventually became Professor of Physics in Würzburg in 1888. Seven years later, it was there that he made the observation that would make his name known far beyond the world of science.

From Discovery to New Field

After his initial observation on November 8, 1895, Röntgen began investigating the new radiation systematically. Just a few weeks later, on December 22, he produced the now-famous X-ray image of his wife Bertha’s hand. The photograph clearly shows her bones and joints – as well as her wedding ring. The image provided striking evidence of the potential of the new technology.

Although Röntgen’s discovery quickly attracted international attention, he did not apply for a patent. He believed that his discovery and its possible applications should be available for the benefit of society as a whole. The technology soon moved from the laboratory into practical use. As early as 1896, Reiniger, Gebbert & Schall (RGS) began producing and selling X-ray equipment. The company would later become part of the Siemens group.

The new technology established itself particularly quickly in medicine. Doctors could now examine bones, foreign objects and structures inside the body without having to operate on the patient. At the same time, the increasing use of X-rays revealed that the radiation was not harmless. Skin damage and burns among physicians and technicians exposed to the radiation were among the early consequences. Over time, these findings led to the development of radiation-protection measures and regulations. Today, X-ray imaging is an established part of medical diagnostics, while computed tomography uses X-rays to produce detailed cross-sectional images of the body.

But X-rays can do more than reveal structures inside the human body. The technology has also become established in a wide range of other fields. In industry, X-rays can be used to inspect components without damaging or altering them. They can, for example, reveal faulty welds, cracks or cavities in castings. In archaeology and the preservation of cultural heritage, X-ray imaging can provide insights into hidden structures within historical objects without requiring them to be opened or damaged.

Although Wilhelm Conrad Röntgen therefore neither invented an X-ray machine nor founded a company, his discovery had far-reaching consequences for science, medicine and technology. In 1901, he received the Nobel Prize in Physics. His name has also remained closely associated with his discovery: In German, the verb »röntgen« has even become part of everyday language – a lasting reminder of the professor from Würzburg who made the invisible visible.