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21 Cards in this Set
- Front
- Back
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What does kVp control ? Higher and lower ? |
Controls contrast Higher kVp is a shorter wavelength & higher frequency Lower kVp is a longer wavelength & lower frequency |
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What does mAs control? |
Primarily controls brightness in digital |
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CPU |
Central processing units are the brains of the computer |
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What is a bit ? |
Single unit of data with a gray color value assigned too each bit |
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How do we get better spacial resolution ? |
By using a greater matrix size for the same field of vision |
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What is spacial resolution? |
Sharpness of an image *limited by pixel size and pixel characteristics |
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Pixel characteristics |
The number of photons detected within the pixel determines the shades of gray displayed |
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Bit Depth |
Number of gray shades that can be displayed within a pixel |
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Increasing pixel depth does what ? |
Increases shades of gray available to display on the digital image improves its contrast resolution |
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Pixel Pitch |
The distance between adjacent pixels & is measured from the center of one pixel to the center of the next |
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What does pixel pitch determine ? |
Spacial resolution |
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CR Pixel Pitch Vs. Dr Pixel Pitch |
Cr is determined by sampling frequency DR is determined by Detector Element (DEL) size |
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CR (computer rafiography) |
Cassette based Photostimulable phosphor plate |
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What is a latent image ? |
The invisible image which can now be processed by the image reader |
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How is a cr plate scanned ? |
Inside the reader the plate is scanned with a laser beam (helium-neon) |
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What does the ADC do ? |
Converts the light released into a digital image |
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Quantization |
When the analog signal is converted (digitized) to digital bits used by the computer |
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Histogram Formation |
A graph of the number of pixels in an image |
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The information that is important on the histogram is determined by ? |
The value of interest (VOI) |
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Look-Up-Table (LUT) |
Determines what numbers are assigned to the input pixel & then changes them to output signals |
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What is the purpose of contrast enhancement ? |
To optimize the image contrast & brightness |
