Röntgen refers to X-rays, a form of electromagnetic radiation that can penetrate various materials, including human tissue. Discovered by the German physicist Wilhelm Conrad Röntgen in 1895, X-rays are widely used in medical imaging to help diagnose conditions and injuries. When X-rays pass through the body, they are absorbed at different rates by different tissues. Dense materials, like bones, absorb more X-rays and appear white on the resulting image, while softer tissues appear darker. This contrast allows doctors to visualize the internal structures of the body effectively.