The
x-ray has been called one of the most significant advances
in all of medical history. It is used in many different ways
in medical diagnosis. An x-ray image is produced when a small
amount of radiation passes through the body and strikes a
sheet of sensitive film placed on the other side of the body.
The ability of x-rays to penetrate tissues and bones varies
according to the tissue's composition and mass.
Bone, which contains calcium, does not let much radiation
through and results in white images on the x-ray film. The
lungs, which are filled with air, allow nearly all x-rays
to strike the film resulting in a black film image.
