X-ray sources: 125 years of developments of this intriguing technology

Why took it nearly four decades, from the first evidence of artificial creation of bremsstrahlung, noted indirectly in literature in 1857 by Julius Pluecker, Professor of mathematics and physics in Bonn, Germany, to Professor Conrad Wilhelm Roentgen's breaking discovery and announcement of X-rays in 1895? Following introductory remarks on the difficulties adjusting the parameters required to generate X-rays and the way medical X-rays occupied clinical routine after Roentgen's revolutionary discovery, and answering the question at the beginning, this paper will discuss in depth the paths taken for improvement up to the present, and some of the culs-de-sac.