X-rays are a kind of electromagnetic radiation, which also includes visible light, radio waves, and gamma rays. X-rays travel at the speed of light, which is 186,282 mi/s, and in straight lines in the form of related electric, and magnetic energy called electromagnertic waves. Because the wave lengths of x-rays are much shorter than those of light, they can penetrate deeply into many substances that does not transmit light.

The History of the X-Ray

X-Rays date back all the way to 1895, when they were discovered by a German Physicist by the name of Willhelm K. Roentgen. He called them x-rays because at first he did not understand what they were, and in scientific terms "X" stands for the unknown.

After Roentgen discovered x-rays in 1895, he experimented with them and soon demonstrated most of their characteristics. Within a few months, doctors were using x-rays to examine broken bones. In the 1896, the American inventor Thomas Edison improved the fluoroscope so it could be used to view x-ray images. During the next 17 years, various scientists and inventors refined the x-ray tube.

In 1913, the Americans physicist William D. Coolidge devised a way to make more efficient x-ray tube. Modern x-ray tubes are similar to the type develop by Coolidge.

In the 1970's radiologists began to use new processes for recording x-ray pictures. One process called xeroradiography, records the image on a sheet of clear plastic instead of on photographic film. Xeroradiography is less expensive and requires less exposure than the old process. Another process is digital imaging, which is the process in which the detectors measure the x-rays that pass through the body and send this information to a computer. The computer then converts the data into an image that is displayed on a television screen and is stored on a magnetic disk.