RAD EXPOSURES: Chapter 5 Flashcards
Which layer used in the indirect flat-panel digital detector is usually either cesium iodide (CSI) or gadolinium oxysulfide (Gd2 O2 S)?
X-Ray scintillator layer
What material is a photoconductor that conducts electrons when struck by light X-ray photons?
Selenium
_produce(s) lateral spreading of light, which destroys the spatial resolution of the image.
powdered phosphors
What is the name of the structure that will detect the light from the CSI scintillator in the indirect flat-panel TFT detector?
sensing area
What is the purpose of the optical system in Flat-Panel Digital Radiography?
reduces the output of the image from the scintillator phosphor to the size of the CCD array
With indirect flat-panel TFT digital detectors, what is used to first convert X-Ray photons into light photons?
Exposure latitude
Which operation addresses the appearance of the image displayed on a monitor for views and interpretation by a radiologist?
post-processing operation
Which type of image is obtained initially from the detector and contains artifacts due to the bad detector elements?
flat-field image
Too much edge enhancement produces image noise and creates_?
“halo” effect
Which processing operation plays a role in image display optimization?
post-processing operations
Define spatial resolution:
The ability of the imaging system to resolve fine details present in an object; refers to sharpness of the image.
Define/describe the purpose of: modulation transfer function.
complex mathematical function that measures the ability of the detector to transfer it’s spatial resolution characteristics to the image.
An MTF of _represents a perfect transfer of spatial contrast information.
1
The dynamic range of a digital detector is the response of the detector to different levels of_
radiation exposure
Which performance characteristic deals with the efficiency of a detector to convert the x-radiation signal at it’s entrance window into a useful image signal?
DQE Digital Quantum Efficiency
