As early as 1896, physicist Wilhelm Conrad Röntgen discovered invisible rays—later called X-rays by him—while experimenting. These rays can penetrate almost any material and darken photographic plates. His first shadow images of his wife’s hand and of a medical colleague attracted international attention. Very quickly, so-called X-ray institutes were established everywhere. During the technological revolution of the past 20th century, modern X-ray systems were developed, consisting of highly sensitive films, intensifying screens, and highly focused, precisely exposed X-ray equipment. This allowed the production of increasingly better, high-resolution X-ray images with ever lower ionizing radiation exposure for patients. Initially used in computed tomography, and more recently in “conventional” X-ray, X-ray-sensitive semiconductor detectors are now employed, enabling digital imaging. These images can be transmitted directly via computers or storage media such as CDs, and are available shortly after acquisition through data networks at remote hospital locations or to the referring physician. Conventional X-ray imaging can produce images of the chest, including the lungs and heart, as well as all bones in the body.