Rad Exposures Test Review

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In digital radiography, the ______ and ______ are permanent part of equipment
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Terms in this set (85)
In digital radiography, the ______ and ______ are permanent part of equipment
Detector, reader
Two part process that converts incoming x-ray photons to light- then converts light to electronic signal
Indirect conversion
Indirect conversions use _______ and a _______
Amorphous silicon, thin film transistor (TFT) array
Directly converts incoming x-ray to an electrical signal
Direct conversion
Two system types in DR
Direct and Indirect conversion
Computed radiography is considered an ______ system
Indirect
Direct conversion systems use _____ and ______
Amorphous selenium, TFT array
Standardized digital imaging software for viewing images
DICOM standard
Matrix rows and columns that give form to the image is a characteristic of _______ imaging
Digital
Pixel box of information transformed into gray scale levels (brightness) is a characteristic of ______ imaging
Digital
Voxels (3 dimensional data) is a characteristic of ______ imagingDigitalSpatial location domain is the _____ locationx, y axisHow radiographers view the image isPixel location and line numberMathematical algorithm that changes an image from spatial location to spatial frequency domainFourier transformationHow engineers view imageSpatial frequency domainWhat is rescaling the histogramIf exposure is outside range the computer will correct the imageA use of a LUTAdjustment of contrastProcessing operations applies to small groups of pixels (kernal) (true or false)TrueLocal processing is known asArea or group processingEdge enhancement or sharpnessHigh pass filteringSmoothing or blurring of the images, reduces noise and decreases detailLow pass filteringDigital imaging quality is described in terms ofSpatial resolution, noiseSpatial resolution is controlled by theMatrix size and number of pixelsDensity resolution is affected byBit depth (how much information)The measure of the sensitivity and accuracy of the image receptorDetective quantum efficiency (DQE)Exposure indicators reflect....Amount of x-ray exposure to an image receptorApproximately _____ mR of exposure is necessary to produce a diagnostic image1A comparison between the actual exposure and the proper exposure received by the image detectorDeviation index (DI)Cassette based- light proof container is used to protect imaging plate- imaging plate stores image until processedPhotostimulable phosphor systems (PSP)Layer of photostimulable phosphor that traps the electron during exposurePhosphor layer (active layer)Most common in phosphor layerBarium fluorohalide bromides and iodides with europium activatorsThe remnant beam from the patient interacts with electron in the barium fluorohalide crystals causing fluorescenceLatent image productionIn latent image production, electrons are trapped in the ______- this is the phosphor centercrystal (f centers)Latent image will lose _____% of its energy in 8 hours25When reading the latent image, imaging plate is scanned by a ______Heium neon laser beamThe latent image is read in a _______Raster patternLaser beam frees the electrons allowing them to return to a lower energy statePhotostimulated luminescenceIf plate is grossly overexposed, a ________ will remainGhosting imageSingle laser point reads in a raster patternPoint scanLaser reads entire line at a timeLine scanQuantifies the average value of the signal-determines the brightness level or grayscale level of the pixelAnalog to digital converter (ADC)Analog signal is converted to a digital signal for the computer to work with by an ______ADCThe movement of the laser across the imaging plateFast scanThe movement of the imaging plate through the readerSlow scanSoftware process that eliminates data that is irrelevant to the exam determined by under and over exposureData clippingInformation that is important to the examValue of interest (VOI)Algorithm chosen to provide appropriate contrast for the body partLUTCan process ______ shades of gray256Window width controlscontrastWindow level controlsdensity/brightnessOperations that are performed between the receipt of the input image from the image receptor an the output image that is viewed on the monitorPoint processingOperations that are mathematical calculations that are applied to only a small group of pixels, although the operation will often be continue until all pixels have been subjected toLocal processingA histogram analysis error will occur whenAn image does not fit in the parameters used for the reference histogramAllows multiple images to be stitched togetherImage stitchingImage stitching is useful forScoliosis studies, full spine, long bone studies, angio of peripheral vesselsIndirect conversion is a _____ step process2Direct conversion is a _____ step process1Step one of indirect processScintillatorStep two of indirect processPhotodetectorsScintillators do what?Converts incoming x-ray photons to light firstPhotodetectors do what?Converts light photons to electronic signalPhotodetectors use what as the conversion materialAmorphous siliconElectronic readout is performed by theCharged coupled device (CCD) or thin film transistor (TFT) arrayUsed for electronic readout of electronic signal coming from photodetector, can be used with direct or indirect systemsTFTReceives exposure and collects signal, then refferred to as a dexel because of its bit depth characterDELSmaller DEL, the ______ resolutionBetterSensing area of DEL is determined by _____Fill factorIncrease fill factor _______ resolutionIncreasesCharged coupled devices are used in ______ conversionIndirectFiber optics couple scintillator toCCDA sensor chip photodetector capable of converting visible light into an electric charge and storing itCCDActive layer of direct detectorAmorphous seleniumBad DELS can createArtifactsLayers of the PSP imaging plateProtective layer, phosphor layer, reflective layer, conductive layer, color, support, and backing layerWhat is the active component of the phosphor layerBarium fluorohalideWhat are other terms for a slow scan?Subscan or translatorPACS stands for?Picture Archiving and Communication SystemDICOM stands for?Digital Imaging and Communications in MedicineHow many shades of gray are in an 8 bit system?256Shades of gray are determined in digital imaging byBit depthPixels contain....Switches for sensing and storingWhat is the active component of the CCD scintillator?Cesium iodideWhat is DEL blooming?Overfilling of the DEL- electrons spill over into adjacent DELSWhat type of technology uses lenses and fiber optics?CCDWhat is a CMOS system?Complementary Metal Oxide Semiconductor System