The Virtual Museum of Medical Physics

How would you like to visit a museum dedicated solely to medical physics? Well, with COVID-19 raging, we shouldn’t visit any museums in person. But how about visiting a virtual museum? The History Committee of the American Association of Physicists in Medicine has recently opened a Virtual Museum of Medical Physics.

The Virtual Museum was launched to celebrate the 125^th anniversary of the discovery of x-rays on November 8, 1895 by Wilhelm Roentgen. Existing exhibits include those about Roentgen, Fluoroscopy, Mammography, and External Beam Radiotherapy. Exhibits under construction include Computed Tomography, Ultrasonic Imaging, Magnetic Resonance Imaging, and Nuclear Medicine. Once it’s done, the Virtual Museum will be a wonderful adjunct to Intermediate Physics for Medicine and Biology. If you want to contribute to developing an exhibit, contact the Virtual Museum.

And now, the story of how Roentgen discovered x-rays, as told in Asimov’s Biographical Encyclopedia of Science & Technology.

ROENTGEN, Wilhelm Konrad 

German physicist 

Born: Lennep, Rhenish Prussia, March 27, 1845 

Died: Munich, Bavaria, February 10, 1923

…The great moment that lifted Roentgen out of mere competence and made him immortal came in the autumn of 1895 when he was head of the department of physics at the University of Wurzburg in Bavaria. He was working on cathode rays and repeating some of the experiments of Lenard and Crookes. He was particularly interested in the luminescence these rays set up in certain chemicals.

In order to observe the faint luminescence, he darkened the room and enclosed the cathode ray tube in thin black cardboard. On November 5, 1895, he set the enclosed cathode ray tube into action and a flash of light that did not come from the tube caught his eye. He looked up and quite a distance from the tube he noted that a sheet of paper coated with barium platinocyanide was glowing. It was one of the luminescent substances, but it was luminescing now even though the cathode rays, blocked off by cardboard, could not possibly be reaching it.

He turned off the tube; the coated paper darkened. He turned it on again; it glowed. He walked into the next room with the coated paper, closed the door, and pulled down the blinds. The paper continued to glow while the tube was in operation.

It seemed to Roentgen that some sort of radiation was emerging from the cathode-ray tube, a radiation that was highly penetrating and yet invisible to the eye. By experiment he found the radiation could pass through considerable thicknesses of paper and even through thin layers of metal. Since he had no idea of the nature of the radiation, he called it X rays, X being the usual mathematical symbol for the unknown. For a time, there was a tendency to call them Roentgen rays, but the inability of the non-Teutonic tongue to wrap itself about the German œ diphthong militated against that. The unit of X-ray dosage is, however, officially called the roentgen.