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Digital Radiography
Digital Radiography: An introduction Chapter 3 (Euclid Seeram)
Question | Answer |
---|---|
____ ________ refers to X-ray exposure of the phosphor plate storage. | Image Acquisition |
Photostimulable phosphors have the property of creating and storing a ____ _____ when exposed to x-rays. | latent image |
The _____ _____ contains the photostimulable phosphor. | imaging plate |
The phosphors that meet the certain radiological requirements are ____ _____ _____ _______. | Barium Flouro Halide: Europium |
The phosphor is usually doped with _________ , which acts as an activator to improve the efficiency of PSL. | Europium |
When x-rays fall upon the PSP IP, the europium atoms are ionized by the radiation and the electrons move from the valence band to the _______ ____. | Conduction band |
Electrons in the conduction band are in a higher energy state and free to move into an electron trap known as the __ ______. | F center |
The number of trapped electrons is ________ to the absorbed radiation. | proportional |
The process of rendering the latent image visible by taking the PSP IP to a CR reader to be scanned by a laser beam. | Photostimulated excitation |
The laser light in the CR reader causes the trapped electrons to move up to the conduction band, where they are free to return to the ______ ____. | Valence band |
When the electrons transition from a higher energy state to a lower energy state: it results in an emission of bluish-purple light referred to as ____________ ________. | photostimulable luminescence |
The PSL from the IP is collected and sent to a _______ ____ that produces an electrical signal which is subsequently sent off to the ADC. | photomultiplier tube |
The time it takes for the latent image to disappear. | Fading |
The PSL decreases by about 25% if the time between exposure and image reading is ___ hours or more. | 8 |
Standard resolution IPs have thick _____ ______ and absorb more radiation. | phosphor layers |
High resolution IPs have thinner phosphor layers and provide _____ images. | sharper |
___ ________ ___ have thinner phosphors which reduce the lateral spreading of the laser light. | High resolution IPs |