Opinion ID: 1773140
Heading Depth: 1
Heading Rank: 5

Heading: x-rays

Text: Roentgen rays are commonly known as x-rays. Images produced on film by these rays are not photographs. Precisely they are roentgenograms, also technically described as radiographs, but best known as x-ray films. When a person examines an x-ray, he is not examining a photograph of the inside of a body, much less seeing inside the body. An x-ray machine produces x-rays that have the unusual ability to penetrate solid matter. The degree of penetration depends upon the density of the body: the greater the density, the less penetration. X-rays passing through a body onto a chemically prepared film form an image when the film is processed or developed. As noted, the more solid or dense the object, the more it absorbs the x-rays. Conversely, the less solid the object, the more easily the x-rays pass on through. In the human body bones and structures containing calcium constitute the densest of barrier to x-rays. Matter with the least density are air and gas. Therefore, when a portion of the anatomy is placed on an x-ray film plate (or cassette surface) and an x-ray is taken, the following takes place: The densest part of the anatomy such as the bone offers the greatest resistance and permits the least number of rays to penetrate through onto the film. That part of the film will be the lightest shade. Where no resistance has been encountered the film will be dark. The part offering some resistance, but not that of bone, will give a grayer, or darker shade than the bone, but not completely dark. The x-ray film is a chemical reproduction of the shadows cast by the object being x-rayed onto the x-ray film plate. In the case of an x-ray film, however, the shadows are light, rather than dark. In this sense an x-ray film is similar to a negative in an ordinary photograph. If a small piece or material, dirt or lint gets onto the undeveloped film, or the film is slightly crinkled when being developed, or is slightly scratched on the surface, this creates a problem in determining whether or not this was a representation of what was in the body, or a defect in the developed x-ray film. Radiologists call these imperfections which appear on the x-rays film artifacts.