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X-ray Properties and Discovery
X-rays are electromagnetic radiation carried by photons. Much like the visible light spectrum, another portion of the electromagnetic scale, X-rays may either pass through, be absorbed by or reflect off a material based on its subatomic structure. The key difference between X-rays and visible light is that X-rays exist farther up on the electromagnetic scale. Thus they have a smaller wavelength and higher energy level. A German physicist named Wilhelm Roentgen discovered X-rays by accident in 1895. Roentgen noticed that a fluorescent screen eliminated one electron beam that was directed at it. Though this phenomenon was well known at the time, Roentgen was puzzled because there was, in fact, a large piece of cardboard between the screen and electron beam. Roentgen experimented with several objects placed between the electron source and the fluorescent screen until finally he placed a hand in the path of the electron beam. He found that he could see the shadowy structure of bones projected onto the fluorescent screen.

X-ray Propagation and Capture
Wilhelm Roentgen's discovery of X-rays undoubtedly constitutes one of the most monumental advancements in modern medicine. As of 2009, X-ray machines utilize powerful cathodes and anodes to produce electron beams. When pointed at a human specimen, the electron beams send X-rays through the body's soft tissue but are blocked by hard tissue such as bone or denser tissue. This projection is either captured on X-ray film or digitally captured by an X-ray sensitive receiver on the opposite side of the human specimen for digital analysis. Scientists and physicians use X-ray imaging alone and in complex tomography to create multiple two-dimensional images of a specimen. This latter process is known as a computed tomography (CT) scan.

X-ray Image Use
Doctors primarily use X-ray images in the diagnosis and analysis of broken bones and tooth structure, and the presence of cancer, gaps, lumps or other problems in soft tissue. Utilizing captured images, medical professionals can diagnose and properly treat simple fractures, fractures that don't break the skin and hidden structural defects within teeth. When combined with CT scans, X-rays help to diagnose brain tumors and bone malformations that may be hidden by other bones, and to guide medical equipment such as needles safely through a patient for less invasive surgery. X-ray imaging also provides a security measure in public buildings and airports to ascertain the contents of bags, purses and luggage. This last utilization aids in screening for devices such as bombs or guns, which contain materials, such as metal, that are dense enough to be adequately imaged with X-rays.

Read more: How X-Rays Work | eHow.com http://www.ehow.com/how-does_4883938_x-rays-work.html#ixzz2PrkL9DrG