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QM Registry Ch. 9
Digital and Advanced Imaging Equipment
Question | Answer |
---|---|
active matrix array | large-area (size of conventional f/s IR's) integrated circuit that consists of millions of identical semiconductor elements deposited on glass base that acts as flat-panel IR |
amorphous | without form |
analog-to-digital converter | device for converting analog electronic signal into digital electronic signal for processing by a computer |
aspect ratio | ratio of width of image displayed on computer or video monitor to height of display |
computed radiography | process of creating digitized radiographic image using photostimulable phosphor |
detective quantum efficiency | measure of information transfer efficiency of detector and is defined as signal-to-noise ratio squared coming out of detector divided by signal-to-noise ratio squared going into detector |
Digital Imaging and Communications in Medicine Group | system of computer software standards that allows different digital imaging programs to understand one another |
digital fluoroscopy | computerized enhancement of fluoroscopic images |
digital radiography | method of obtaining digitized radiographic image utilizing active matrix array |
digital subtraction angiography | electronic method of enhancing visibility of vascular structures involving digital fluoroscopy |
digital x-ray radiogrammetry | measure of distances on image and computer software calculates bone volume based on measurements of cortical bone thickness, bone width, and texture analysis |
direct-to-digital radiographic system | method of creating digital radiographic images; involves installing flat-panel IR in the Bucky of radiographic table or upright Bucky, which sends electronic signal directly to digital image processor; AKA flat-panel or flat-plate imaging |
dual-energy x-ray absorptiometry | x-rays with two separate energies used to obtain bone density data |
F-center | empty lattice sites in photostimulable phosphors where crystal electrons are trapped following exposure to x-ray energy |
fill factor | percentage of pixel area that's sensitive to image signal (contains x-ray detector); for most current systems is approximately 80% bc some pixel area must be devoted to electronic conductors and TFT |
image enhancement | use of computer to improve or enhance an image |
image management and communication system | computerized system for storing pt images and medical records |
image restoration | process in digital imaging whereby final image is displayed |
liquid crystal display | flat-panel display form for monitors |
Nyquist frequency | highest spatial frequency resolved by imaging system, measured in lp/mm |
photostimulated luminescence | barium fluorohalide material used to capture radiographic images in computerized radiography CR systems |
picture archiving and communication system | computerized system that stores pt images to allow access from remote locations |
preprocessing | anything done to image data before they are entered into computer memory |
postprocessing | manipulation of image data in memory of computer, before image is displayed on monitor |
refresh rate | refers to how many times each second that a video or computer monitor rewrites or updates image on display of monitor; AKA frame rate or vertical scan frequency |
special procedures laboratory | area in which angiographic, cardiac, and interventional procedures are done within diagnostic imaging departments |
specular reflection | type of reflection coming from surface of electronic display that produces a mirror image of light source creating it |
teleradiology | process of sending digitized images to distant locations for interpretation and consultation |
thin-film transistor | switches for each pixel of array connected to circuity that allows all switches in a row of array to be operating simultaneously |
window level | value in digital imaging that selects level of displayed band of values within complete range |
window width | value in digital imaging that selects width of band of values in digital signal that can be represented as gray tones in image |