Digital Image Processing
How many bits are in one byte?
8 bits in 1 byte.
In CR systems, what is the image referred to as before and after processing?
Latent= Before
Manifest= After
What are the two classes of DR panels?
Indirect and Direct
What is an example of a Digital Marker that can be added after an image is captured?
Upright, Supine, Decub, Cross-table, Inspiration, Expiration... R and L can be added, but it is better practice for them to be from the lead markers.
What are the two types of distortion?
Size and Shape
What is the 2D/picture element of the matrix?
A Pixel
What are the two common CR PSP phosphors?
Barium Flourohalide Bromides 85% (BaFBR:Eu)
Barium Flourohalide Iodides 15% (BaFL:Eu)
What do Direct Detectors use as a photoconductor?
Amorphous Selenium
What is an example of a type of Digital Artifact?
Quantum mottle, inadequate exposures, algorithm artifact, histogram analysis error, non-parallel collimation, poor grid alignment.
What is additive and subtractive pathology?
Subtractive= pathology that decreases density.
What is the 3D/volume element if the matrix?
The Voxel
Where is the Latent Image stored in a CR PSP?
In the Europium holes/ F centers
What is the photodiode of an Indirect Detector made of?
Amorphous Silicon
What is the ASRT's position on cropping?
It should not be performed because it may result in a missed incidental finding.
A digital receptor has a _____ response to radiation exposure.
Linear
Smaller pixels= _______ resolution?
Higher
What determines pixel bit depth in CR?
The ADC
What are the two types of scintillators?
Cesium Iodide (CsI)- *Preferred*
Gadolinium Oxysulfide (Gd2O2S)
What causes data drop?
DEL Saturation; Excessive exposure.
How does atomic number affect attenuation?
High atomic number = high attenuation
What are the three types of image processing?
Point, Local, and Geometric
Name the layers of the CR PSP.
Protective, Phosphor, Conductor, Support, Light shield, Backing.
Does a high TFT fill factor yield a higher or lower spacial and contrast resolution?
It yields a higher spatial and contrast resolution.
What is the Deviation Index "sweet spot"?
-0.5 to +0.5
-3 to -1 is underexposed
+1 to +3 is overexposed
What is spacial resolution?
The sharpness of anatomical structures that are displayed on the IR.