X-rays, fluoroscopy, ultrasound, computerized tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) scans - the use of medical imaging has become a routine part of healthcare today. In January 1896, though, when the news of Wilhelm Roentgen's discovery of X-rays swept around the world, the very idea of looking inside the living body was inconceivable. However, by the 1920s, this technology was commonplace. Over the course of the century, X-rays, floroscopy, and the newer inventions transformed the practise of medicine.