Final exam review Flashcards
ability to distinguish between similar objects as having different shades of gray
contrast resolution
exposure error still resulting in a quality image at an appropriate dose
exposure latitude
how accurately a system converts x-ray input signals into a useful output image defines:
MTF
how efficiently a system converts x-ray input signals into a useful output image defines:
DQE
when was computed radiography introduced?
1981
what are the different layers of the phosphor layer?
conduction band (traps electrons)
valence band (houses electrons)
phosphor layer
what is the purpose of the reflective layer?
sends light toward the photodetector
what is the purpose of the conductive layer?
absorbs and reduces static electricity
what type of phosphor is typically used in computed radiography?
barium fluorohalide doped w/ europoum
the second emission of light during exposure of a CR imaging plate represents:
electrons being released due to the red laser scanning the plate
what is the latent image?
trapped electrons in the PSP
what is the manifest image?
image that shows up on the computer
list the steps needed to produce a manifest image:
what sends an electrical signal to the ADC?
photodetector/photomultiplier
what is a histogram?
graphical display of the pixel intensity distribution for digital image
what is rescaling?
adjusts overall exposure up or down to correct exposure errors
what is the controlling factor in producing image contrast?
increased contrast resolution
how do we adjust image brightness?
window level
how do we adjust image contrast?
window width
what controls an imaging system’s ability to produce differing levels of contrast resolution?
bit depth
what is smoothing?
reduction of noise
what is equalization?
making underexposed areas dark and overexposed areas light
how do we erase IPs after use?
flood them with white light
how many shades of gray can a system that has a bit depth of 10 show?
1024
how is spatial resolution measured?
line pairs/mm
specific to DR, list three factors that contribute to spatial resolution:
these factors share a ________ relationship with spat. res.
speed class
phosphor layer thickness
laser diameter;
direct
