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QM Registry Ch. 8
Quality Control of Fluoroscopic Equipment
Question | Answer |
---|---|
automatic brightness control | AKA automatic brightness stabilization; it is an electronic method of regulating fluoroscopic image brightness level for variations of pt thickness and attenuation |
automatic gain control | electronic method of regulating image brightness |
brightness gain | degree of image brightness increase obtained with an image intensifier |
charge-coupled device | two-dimensional electronic array for converting light patterns into electronic signals |
cinefluorography | recording of a fluoroscopic image onto motion picture film |
flux gain | gain in image brightness occurring with image intensifier during fluoroscopy resulting from high voltage across the tube |
high-contrast resolution | ability to resolve small, thin black-and-white areas |
image intensifiers | electronic device that brightens fluoroscopic image |
image lag | an image persisting on cathode-ray tube even after termination of radiation |
image-orthicon | type of TV camera tube; largest and most sensitive type of TV camera and functions as both an image intensifier and TV pick-up tube; sensitive to temp changes; req's long warm-up time |
kerma | acronym for linetic energy released in matter, it measures amount of kinetic energy that is released into particles of matter (i.e electrons made from Compton and PE interactions) from exposure to xrays |
low-contrast resolution | performance variable measuring ability to image structures of similar density |
minification gain | an increase in brightness with image intensifier tubes as result of difference in size between input and output phosphors. |
multifield image intensifier | specialized image intensifier that allows for magnified fluoroscopic images |
photoemission | emission of electrons from material after exposure to light or other ionizing radiation |
photofluorospot | method of recording static images during fluoroscopy |
pincushion distortion | type of distortion in image-intensified images caused by projection of curved image onto flat surface |
plumbicon | type of TV camera tube; uses lead oxide as target phosphor and is often used in digital fluoroscopy bc of its short lag time |
relative conversion factor | measures amount of light produced by output phosphor per unit of x-radiation incident on input phosphor |
S distortion | artifact that can occur in image intensifier tubes consisting of warping of image along an S-shaped axis |
veiling glare | glare caused by light being reflected from window of output phosphor in image intensifier; AKA flare |
vidicon | type of TV camera tube; currently most common type of video camera in fluoroscopic systems; target material is antimony trisulfide; long lag time to help reduce image noise |
vignetting | decrease in brightness toward periphery of fluoroscopic image when using image intensifier tube |