Week 1 Flashcards
What are the three types of x-ray?
Conventional, CR (Computed Radiography), DR (Digital Radiography)
Radiography that uses intensifying screens and film
Conventional Film/Screen Radiography
Another name for Computed Radiography that is used more often
Photostimulable Phosphor (PSP)
Digital acquisition modality that uses storage phosphor plates to produce projection images
PSP (CR)
Where are film intensifying screens primarily used?
Conventional Radiology
Acquires image through use of photostimulable phosphor plate storage
CR - Computed Radiography
What generally stays the same when comparing computed and conventional radiograhy?
Efficiency levels
What is the active element in a phosphor plate?
Barium Fluorohalide
In reference to a psp image capture to release the latent image a ___ ____ ____must be scanned over
Focus Laser Light
Indirect capture is very similar to PSP systems in that the X-ray energy stimulates a ____which gives off light that is detected and turned into an electrical signal
Scintillator
Converts x-ray energy directly to a digital electrical signal?
photoconductor
Exposure latitude in conventional is equivalent to what in DR?
Dynamic range
What is a look-up table ?
Maps the image gray scale values
What are the components of PACS?
Reading stations, physician review stations, web access, technologist quality control, administrative stations, many interfaces to various hospital and radiology systems.
What type of imaging would require all new equipment?
Digital Radiography
T/F - Indirect capture converts absorbed energy into visible light.
True
T/F - Changing matrix and FOV will not change the pixel size.
False
What is each square in a matrix called?
picture element
Term for Number of bits per pixel
Bit Depth
What does exposure index refer to?
Amount of exposure received by the image receptor (not the patient)
The difference between the actual exposure (Kind) and the Target (Ktgt) exposure
Deviation Index
Ability of the digital system to display subtle changes in the shade of gray
contrast resolution
Ability of the imaging system to demonstrate small details of an object
spatial resolution
How efficiently a system converts x-ray input signal into useful output image
Detective quantum efficiency (DQE)
T/F -Reflection of ambient light can be problematic
true
Failure of the system to find the collimated edges can result in…
incorrect data collection, and images may be too bright or too dark
Histogram displays the useful image by locating….
minimum and maximum signal within the anatomic regions of interest
The higher the kvp, the more ___ the histogram, the lower the kvp, the more ___ the histogram
narrow, wider
Result when not enough pixels in image.
Low resolution
When exposure is greater or less than what is needed to produce an image, this occurs in an effort to display the pixels for the area of interest
Automatic Rescaling
Images are produced regardless of this amount
contrast and density
If you change the slope of a look up table this decreases/increases what?
contrast
An improper algorithm application may cause image to
enhance contrast
Term for Amplifications of frequencies
Edge Enhancement
Suppressing frequencies that can result in the loss of detail
masking
Low-pass filtering is best used for what type of anatomy images?
Bones
High-pass filtering is best used for what type of anatomy images?
organs and tissues
What do image level parameters control on a image?
brightness
What controls the ratio of black and white, or contrast, on a image?
window width
When unexposed borders around the collimation edges allow excess light to enter the eye.
veil glare
Image manipulation used to blacken out the white collimated borders, effectively eliminating veil glare
Automatic Shuttering
Used when anatomy or the area of interest it too large to fit on one cassette, multiple areas can be “stitched” together using specialized software programs
Image Stitching
What is the shape of a histogram specific to?
anatomy
