dig img quiz 1 set1 Word Scramble
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Question | Answer |
When was the flouroscope invented and by who? | Thomas A. Edison in 1896 |
What was the early flouroscopic screen (II) made of? | Zinc-Cadnium Sulfide |
Who is responsible for the development of the screen (II) in 1941? | William Chamberlain |
What type of vision are the rods of the eye used for? | scoptic or night vision |
Where are rods found in the eye? | around the periphery |
Why type of light do rods use? | dim/low light |
What are the cones of the eye used for? | visua acuity, contrast and brightness differentiation |
Where are the cones of the eye found? | around the fovea centralis |
What type of vision are the cones of the eye used for? | photooptic/color vision |
What part of the eye is the image intensifier designed to utilize? | cones |
Visual acuity | ability to peserve fine detail (cones) |
Contrast perception | ability to detect differences in light levels (cones) |
protective covering of the eye: | cornea |
light projected through the cornea is focused where? | through the lens and onto the retina |
how long is the image intensifier? | 50cm |
what is the potential difference applied to the image intensifier? | 25,000 Volts (25 kV) |
what is the lead equivalency of the image intensifier and why? | minumum 2mm Pb eq, it is a primary barrier. |
What is the function of the input phosphor | convert the remnant x-ray beam to visible light |
What is the input phosphor made of? | cesium iodide |
What is the function of the photocathode? | converts light to electrons (photoemission) |
Photoemission | electron emission after might stimulation |
What is the photocathode made of? | cesium and other e- emmiting coponents |
What type of charge does the electrostatic focusing lens have and why? | negative, to repel e-s and direct them toward output phosphor |
How much of what material makes up the output phosphor? | 2.5 to 5cm zinc-cadnium sulfide |
What does the output phosphor do? | convert electrons to visible light |
In the flux gain formula, flux gain equals what? | number of input light photons / number of input x-ray photons |
What is flux gain? | measure of increase in light photons at the output phosphor to x-ray photons at the input phosphor |
What controls flux? | mA |
What is brightness gain? | ability of the image intensifier tube to increase illumination level of the image |
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annaluz87
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