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chapter 1 and 4 test
Question | Answer |
---|---|
what is the best mechanism to control involuntary motion during an exposure | shorten exposure time |
which one of the following changes will improve image resolutions | decrease OID |
the misrepresentation of an object size or shape projected onto a radiographic recording medium is called | distortions |
through careful selection and control of exposure and geometric factors, it is possible to elminates all image distortions | false |
list the four primary controlling factros for distrotion | SID OID objects IR alignments central ray placements |
a decrease in SID reduces distortions | false |
an increase in OID reduces distortions | false |
distortion is reduced when the central ray (CR) is kept perpendicular to the plane of the image recetpoor | true |
the SID for general radiographic procedures resulting in maximum recorded resolution is | 44 inches |
a chest x-ray on a patients with an enlarged heart has been request which SID is recommended for this study | 72 inches |
every radiographic images reflects some degree of penumbra or unsharpness, even if it the smallest focal spot is used | true |
as the distance between the object and the image receptor is increase, magnification sis reduces | false |
image distortions increase as the angle divergence increase from the center of x-ray beam to the outer edge | true |
the greater the angle of inclinations of the object or the IR, the greater amount of distortions | true |
digital imaging requires that images be chemically processed | false |
digital images are numeric representation of the x-ray intensities that are transmitted through the patients | true |
digital imaging system have a narrow dynamic ranges | false |
digital processing involve the systematic application sof highly complex mathematical formula scalled | algoithms |
the range of level of image contrast in the digital image is primary controlled by | digital processing |
exposure latitude with digital imaging is more ______ when compared to anag imaging | wide |
list the six image quality factors to evaulate digital images | brightness contrast spatial contrast distortion exposure indicator noise |
in digital imaging the term ____ replaces density as applied in analog base imaging | brightness |
changes in mAs do not have primary controlling effects on digital image brightness | true |
brightness cannot be alter in the digital image onces it has been process | false |
a digital imaging systems ability to distinguish abetween similar tissues is termed | contrast resolutions |
radiographic contrast in the digital image is primarily affected by | applications of processing algoithms |
the greater the bit depth of a digital imaging system, the greater the | contrast resolutions |
list the term describing the two pixel size used in digital imaging | acquistion pixel size display pixel size |
which of the two pixel size listed above is most critical in maintaining high resolution digital images | acquistiion pixel size |
focal spot size has no impact on the resolutions of the digital image | false |
the current range of the spatial resolutions for digital rdaiographic imaging system is between the | 2.5 lp/mm to 5.0 ip/mm |
in addition to acquisition pixel size, spatial resolution in the digital image is controlled by | display matrix |
the factor that affect image distortion for the digital image are different from those that affect film-screen system | false |
a numeric value that is represenative of the exposure the digital image receptor receive is termed the | exposure indicator |
list the four factors that affects the exposure indicator in the digital images | mAs kV total detector area iirrdicated objected exposed |
if the recommended exposure indicator range for a well-exposed image is between 15- to 250 a vaule of 350 would indicated ______ of the images | underexposure |
if the recommended exposure indicator range is between 2.0-2.4 thena value of 1.2 indicates _____ of the images | underexposure |
a random disturbance that obscures or reduces clarity is the definition for | noise |
verifying the exposure indicator for each exposure is essential in producing quality digital images withe the | least possible dose to the patients |
when insufficents mAs is applied in the production sof a digital images it produces a _____ SNR images | low |
another term for image noise is | mottle |
changing or enhancing the electronic image to improve its diagnostic quality is | post-processing |
radding text to images | annotations |
increasing brightness along the margins of structure to increase the visibility of the edges | edge enhancements |
reverseing the dark and ligh pixel values of an images | image reversed |
enlarging all or part of an images | magnifiations |
the application sof specific image processing to reduce the display of noise in an images | smoothings |
removing background anatomy to allow visualizations of contrast media-filled structure | subtractions |
list the three componenets of a photostimulable storage phosphor plates (PSP_CR) systems | image plate IP reader techniologist QC workstations |
a PSP - based digital imaging system may be cassette based or cassette-less | true |
the term describing the iamge being transmitted to a digital archive for viewing and reading by the referring physician or radiolgist is | image archiving |
when using a PSP image plate, patients data can be linked to the image by use of an | bar code reader |
once the PSP image plate has had an image recorded on it it must be discarded | false |
the latent image on a psp image plate is read by a laser within the CR reader | true |
the greater the exposure to th eplate, the greater then intensity of the light emitted from the plate during the reading process | true |
any residual image is eraased on the PSP image plate by applying | bright lights |
the process of transferrring the digital image to a storage device is termed | archeving |
the process of transferring the digital images to a storage devices | archeving |
fifty percent of the IP must be exposed to produce a correct reading of the images | false |
the use of grids is optional with PSP because the IP is not as sensitive to scatter radiation as analog radiography | false |
patients dose may be lower the FPD_TFT as compared with analog radiography | when using FPD_TFT for most nongrid procedure,s one rease the grid is gnerally not removed is its fragil constructions |
FPD_TFT and PSP based systems does not provide the ability to view a previous image to evaluate for position errors and confirm the exposure indicator | false |
in additions to FPD_TFT and PSP based systems a third type of system is used to acquire radiographic images distiallly which is | CCD_ based system |
the size of the image receptor used is dependent primarily on the size of the body part being examined | true |
a PACS automatically trasported film-based images to the chemical processors after they ahve been exposed | false |
the electronic transmission of diagnostic imaging studies is termed | teleradiology |
the _________receptor is made with amorphous selenium or amorphous silicons | FPD_TFT |