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Concerning image acquisition in computed radiography: a. It depends on fluorescence within the X-ray screen b. An image plate is used c. The equipment chosen will depend on the degree of resolution required d. The latent image is stored by electrons located within the valence bands of the phosphor e. It requires electrons to return to their resting state for the image to be obtained |
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Answer» a. False. It depends on photo-stimulated phosphorescence. Fluorescence describes the emission of light immediately after the phosphor is exposed to X-rays, while phosphorescence describes delayed emission, which is the property exploited in computed radiography. b. True. This is the name for the screen comprising barium fluorohalide crystals (halogen elements of bromine, iodine and chlorine) with europium ions, which are usually embedded in a light-reflective layer. c. True. High-resolution image plates are designed with a thinner layer of phosphor crystals without a light-reflective layer. The compromise with these plates is that they will require a higher dose to obtain an adequate image. d. False. Electrons located in ‘electron traps’ within the phosphor store the latent image. These represent energy levels, which differ from those in which the electrons usually exist (the valence bands) prior to irradiation. e. True. |
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