Wilhelm Rönteng born in March of 1845 in Lennep, Germany. He was a problematic boy because he was expelled of the High School for draw a cartoon of his teacher who never believed in him, but in 1900 he managed to be a Physics Professor and later he was the headmaster of Wüzburg University
On November 8, 1895, when he was experiencing the power of penetration of cathode rays whit a pipe or tube of de Hittorff-Crookes.
He observed that a cardboard plate covered with platinum-barium cyanide crystals emitted a fluorescence an this dissapeared when he discconect electricity
He soon discovered that these rays, which he called "X", suddenly through different types of materials such as paper, wood, a thin sheet of aluminum, etc... and Lead
He also realized that by holding a lead ring with his fingers, he not only saw the ring but also the bones of his hand. He thought he could "print" the image on a photographic plate.
They are a great support for diagnosis in medicine, but they are also used in airport scanners.