Medical imaging was discovered just like many of histories greatest inventions, by accident in 1895. Physicist Wilhelm Roentgen was working with electron beams in a glass tube and noticed a fluorescent screen in the lab glowing when the beam was turned on. He found that even though his screen was covered with heavy black cardboard, waves of some type penetrated it. He put items between the screen and the tube, and found that he could see through or into items. The most famous being his wife ?s hand. He called his discovery X-rays (X standing for unknown). Roentgen placed a photographic plate behind the screen, and found the image of the bones in her hand and a ring on her finger could be captured on it just like the photographic processes of the day.
Even though the first X-Ray clearly showed the bones in the hand, the uses were not medical at first. Radiography at the time was considered akin to photography. Most of the equipment was owned by independent businessmen who opened up shops to give the curious public a look at their bones for a small fee.

The main medical application for the new discovery was for chest X-Rays for the early detection of tuberculosis, the leading cause of death at the time and diagnosing broken bones. By 1906 a contrast medium for the renal system (kidneys) was developed, followed several years later by Barium Sulfate to add contrast to gastro-intestinal X-Rays. These contrast liquids were administered by mouth, or injection, and absorb X-rays better than surrounding soft tissue, making it easier to see in X-Rays.

It would be another five years before Marie Curie ?s Theory of Radioactivity was published. In the meanwhile X-Rays began showing up in doctor ?s offices around 1910. Doctors would operate the equipment themselves, and soon recognized that doing routine maintenance on equipment was a poor use of a physicians time. The job was turned over to office assistants, who in many cases had no training in anatomy. It would not be known until twenty years after the discovery of X-Rays that protective lead lined garments needed to be worn while administering X-Rays The death rate among office assistants was high in the early days. Exposure times were high, for example, it would have take over ten minutes exposure to get an image that could be made in less than a second today, The American Association of Radiological Technicians was formed in Chicago in 1920 to standardize the practice of Radiology and establish an ethics code.

Gains in medical imaging technology came slow after the initial discovery of the X-Ray, but the science that would eventually become state of the art in medical imaging was being developed in the 1920 ?s through the 1970 ?s. Work on sonic waves, or SONAR was discovered to image under water in World War I, but did not see widespread use until World War II. Separate studies were on going, Radio Frequency, Magnetic Resonance, and hydrogen atom studies and how atoms align were studies in the 1930 ?s and 1940 ?s funded by the U.S. Government, Department of Defense. These studies would come together some years later as MRI technology.

Most technological gains over the next 30 years were in ways to X-ray parts of the body that could not be imaged before. Coronary artery imaging began was first used in 1945, Nuclear Medicine in 1950, ultrasound in 1960, X-Ray mammography in 1970. Technological advances became coming at a much faster rate after the CAT scan was introduced in 1972. Every year since has marked a great improvement in one area or another of medical imaging.