Image Quality Flashcards
What are image evaluation factors
Contrast
Distortion
Spatial resolution
IR exposure
Gross exposure error
Quantum noise
Radiation fog
Artifacts
Markers
What’s another word for grayscale
Contrast
What is visual darkness referred to
Brightness
What is low brightness
Black areas
What is high brightness
Bones
What is is called when there is a big difference between dark & bright areas ( hand xray)
High contrast
Short scale
What is it called when there is a small difference between dark & bright areas ( ankle xray)
Low contrast
Long scale
What is contrast
The difference between areas of brightness on an image
What is exposure criteria
When brightness and contrast are in proper balance
What are the 2 reasons grayscale is important
- Still need to evaluate images for criteria
- Knowing criteria helps to know if image is diagnostic or not
What is distortion
The size and shape of anatomical structure
What is spatial resolution
Sharpness of anatomical structure on the image
-looks blurry
What is the number 1 cause of poor resolution
Motion
What other factors effect spatial resolution
SID, OID
FOCAL SPOT
IMAGE RECEPTOR
PIXEL SIZE
What is image receptor exposure
The dose received by the imaging plate
Good image quality is based on what ?
The IR receiving an appropriate exposure
How is proper IR exposure determined
by the exposure indicator value (deviation index) DI
What is Gross exposure error
excessive IR exposure & poor image quality
what is saturation
part of gross excessive IR exposure
part of image can’t be interpreted
what is ghosting
IR received so much exposure that it’ll show in next image
what is quantum noise (mottle)
Graininess of an image
what causes quantum noise (mottle)
insufficient IR exposure
(Grainy image )
what is radiation Fog
Hazy, grayness obscuring anatomy
excessive scatter due to large body part (large pt w/o grid)
what are artifacts
objects or technical errors obscuring anatomy
