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This is a picture of a a diagram on how a x-ray process works

Computed Radiography

What is CR?

CR stands for "computed radiography". Simply put, it is like a digital camera that is able to store images in a digital form instead of on a conventional form such as film. Conventional radiography uses x-ray film to store images; CR radiography uses a phosphor plate to store an image until it is processed with a special processor that turns it into a digital form which is able to be saved in a computer. When x-rays interact with the phosphor plate, the atoms are raised to an excited state. The phosphor plate is then scanned by a very thin laser beam in the processor which allows the phosphors to release their energy in the form of violet light and the phosphors return to there unexcited (ground) state. The violet light is then captured by the processor and assigned a value corresponding to its intensity and saved in the computer. This image can then be saved to a computer disc to be taken to a doctor appointment or printed off on film at a later date without worrying about image degradation.

What Are The Advantages of CR?

Since CR images are stored in digital form they are able to be archived and accessed by multiple people at the same time. This is useful when x-rays need to be read by our radiologist but you also need to have them for another doctor to look at. Now we can have both. Before CR, films could get misplaced or never returned from doctors office appointments, but now they are permanently stored in our PACS archive. Also, copies of x-rays used to be severely inferior in quality to the original because the process was like taking a picture of a picture. On x-ray copies much pathology could be missed. Now, the original information is stored in the computer so that every film that is printed off whether the first or hundredth time looks identical. Another advantage of CR is the dynamic range (the # of shades of gray that can be seen). X-ray film is only capable of storing a limited number of shades of gray. With CR, contrast and brightness can easily be manipulated so that a much wider range of information can be seen. One more advantage of CR is faster reading time. X-rays used to be hung on view boxes for radiologists to read and taken down and filed afterwards, a very timely process with room for human error such as misfiling. Now the radiologist is able to eliminate this entire process by simply pulling up a list of patient names and choosing whomever he needs.


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