fauber questions: chapter 4, 5, and 9 Flashcards
which of the following would improve spatial resolution?
-large matrix
-large pixel size
-decreased pixel density
-increased pixel density
large matrix and increased pixel density
the type of IR that uses a PSP to acquire a latent is ______________-
computed radiography
what is used to extract the latent image from an imaging plate?
laser beam
(increased/decreased) sampling frequency and (increased/decreased) sampling pitch will improve spatial resolution
increasing, decreasing
what will improve spatial resolution of the digital image for a given FOV?
-large/small/fixed matrix size
-large/small IP
fixed matrix size and a small IP
does a higher or lower bit depth give a greater range of shades of gray?
higher bit depth
small anatomic detail has (high/low) spatial frequency
high spatial frequency
___________ refers to the range of exposures that should be used to produce a diagnostic image
exposure latitude
true/false: a lower SNR improves quality of an image
false
true/false: decreasing the displayed FOV for a given matrix size will decrease the size of the pixels and increase spatial resolution
true
what is a measurement of the efficiency of an IR in converting the x-ray exposure it receives to a quality radiographic image?
DQE
a higher sampling frequency during CR latent image digitization will ____________
increase spatial resolution
what will provide an indication of patient radiation risk during a radiographic procedure?
DAP and KAP
image artifacts can be caused by…
-dirty CR plates
-low sampling frequency
-increased pixel density
dirty CR plates, low sampling frequency
graphic representation of pixel values is a ___________
histogram
what process is employed to maintain consistent digital image brightness for over or underexposure?
automatic rescaling
which of the following is not a numerical value indicating the level of radiation exposure to the IR?
-sensitivity number
-exposure indicator
-window level
-exposure index
window level
which of the following may impact the location and shape of the histogram?
-exposure technique
-positioning
-collimation
1, 2, and 3
what digital process alters image brightness and grayscale to improve visibility of anatomic structures?
lookup tables (LUTs)
true/false: maintaining a low level of ambient lighting can improve soft copy viewing of digital images
true
display monitors used for soft-copy viewing of digital images should have __________
high luminance
which of the following is not a function during post-processing of displayed digital images?
-histogram analysis
-electronic masking
-windowing
-edge enhancement
histogram analysis
wider window width (increases/decreases) (brightness/contrast)
decreases contrast
what postprocessing technique suppresses image noise?
smoothing
what is the communication standard for information sharing between PACS and imaging modalities
DICOM
true/false: the DI is a value that reflects the difference between desired or target exposure to the IR and actual exposure to the IR
true
true/false: a DI of -0.75 reflects insufficient exposure to the IR
false
DI values of 0.5 to -0.5 are _____________
within target range
which of the following may occur as a result of the DI value greater than +3.0?
-excessive noise visible
-saturation
-patient over exposure
2 and 3
to transmit and store large amounts of imaging data, what may occur?
compression
what is the latent image center for radiographic film?
sensitivity speck
what describes a film’s sensitivity to x-rays or light?
speed
intensifying screens are used to _________
decrease patient exposure
what automatic processing system primary maintains the chemical activity level?
replenishment
what term is defined as a measure of the amount of light transmitted through the film?
optical density
what is the diagnostic range of optical densities?
0.5 to 2.0
a change of ____________ in OD results from a change in the percentage of light transmittance by a factor of 2
0.3
changes in radiation exposure have the greatest effect on optical densities in which sensito-metric region?
straight line
when the exposure technique used produces densities outside the sight-line portion of a senito0metric curve, how was contrast affected
decreased
