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Digital Xray Imaging
Radiography for Veterinary Technicians
| Question | Answer |
|---|---|
| Define Resolution | related to the size of the pixels that make up the image- A lot of smaller pixels= sharper image; fewer, larger pixels= less sharp, grainy |
| Describe Image Noise | random variations in the shades of gray— caused by electric or quantum interference— more noise equals decreased contrast |
| What is the term used to describe increases in exposure factors made in an attempt to reduce the amount of image noise? | Dose creep |
| What controls the range of densities displayed on the final image? | Windowing |
| What is the material used with digital radiography (DR) systems that fluoresces when exposed to the X-ray beam? | Scintillator |
| What can incomplete erasure of the imaging plate (IP) result in? | Ghosting |
| What device do direct detector DR systems utilize to detect and display the image? | Thin-film-transistor (TFT) |
| What % of the image on an IP will be lost in eight hours? | 25% |
| What describes the sensitivity and accuracy of the digital system? | Detective quantum efficiency |
| Aside from a TFT detector, what else do Indirect digital systems use to detect fluorescence? | Charged-couple-device (CCD) |
| Differentiate between computerized radiography and direct digital imaging. | CR systems require a cassette with intensifying screens, whereas DDI systems have image receptors built into the table. These are converted to digital data in real time. CR requires the imaging plate to be put into a reader. |
| What factors determine image quality? | resolution, noise, pixel size & number, and field of view |
| What is the difference between direct detector systems and indirect detector systems? | The mechanism in which images are produced- DD uses thin-film-transistor to collect & convert electrons. ID uses a scintillator to detect and convert light energy |
| What is a pixel? | the smallest component of the digital image matrix |
| How do you try to remove image noise? | using higher mAs or kVp can minimize noise, as noise is directly inverse to contrast |
| What type of cassette screen is used in CR? | a screen composed of photostimulable phosphors |
Created by:
BrianaPenn
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