The use of high-mAs, low-kVp and of slower image receptors reduces______ .
quantum mottle.
Fast image receptors have___ noise and low spatial resolution and low contrast resolution. 1)no Noise
2)Low Noise
3)High Noise
3)high
Fast image receptors have High noise and____ spatial resolution and low contrast resolution.
1)no spatial resolution
2)Low spatial resolution
3)High spatial resolution
2 Low
Radiographic noise has four components:
film graininess,
structure mottle,
quantum mottle,
scatter radiation.
·
The principal source of radiographic noise is
scatter radiation
Distribution of phosphor crystals in an intensifying screen is called
Structure mottle
Radiographic noise produced by the random interaction of x-rays with an intensifying screen. This effect is more noticeable when very high rare Earth systems are used at a high kVp. this is called
Quantum mottle
Lower noise results in a better radiographic image because it improves contrast resolution.
true or false
true
The Ability to image small objects that have high subject contrast is called.....
Spatial resolution
Spatial resolution improves as screen blur 1)decreases
2)Increases
3)No Change,
1)Decreases
the ability to distinguish anatomical structures of similar subject contrast such as liver–spleen and gray matter–white matter.is
Contrast resolution
refers to the ability to visualize recorded detail when image contrast and optical density (OD) are optimized.
Visibility of detail
Degree of sharpness of structural lines on a radiograph.
Detail
the random fluctuation in the OD of the image.
Radiographic noise
Sensitivity is the ability of the CCD to detect and respond to very____ levels of visible light
low
________ is the ability of the CCD to respond to a wide range of light intensity, from very dim to very bright.
Dynamic range
The CCD has Lower sensitivity for radiation and a much wider dynamic range than screen-film image receptors.
True or False
False
CsI/CCD is an indirect DR process by which x-rays are converted first to light and then to electric signal. .
True or False
true
The percentage of the pixel face that is sensitive to x-rays is the ______.
fill factor
The fill factor is approximately___%; therefore, ___% of the x-ray beam does not contribute to the image.
80%
20%
_________ in DR is pixel limited.
Spatial resolution
a-____ is a direct DR process by which x-rays are converted to electric signal.
Se
special optics that can keep beam size shape and speed independent of the beam position
beam shapeing optics
moves laser beam rapidly back and fourth across the screen to stimulate sequentaily each point along the scar line
Beam Deflector
the _____ are used to collect as much of the emitted light from the screen and channel with minimal loss to the photo-detector where it is converted into a electrical image
Light Collection Optics
the____ plays a crucial role in keeping the stimulated light from entering the photo detector and swamping the desired image signal
optic filter
the___ converts the emited light photons into an electrical signal that can be processed into a digital image
Photo-Detector
______ refers to a continuously varying quantity; a digital system uses only two values that vary discretely through coding. .
