Components of Radiographic Image Quality. Radiologic Technology 244 created: Fall 2005 Rev 12-01-2009. Review handouts. Main Factors Affecting Recorded Detail. kVp & mAs Technique Selection (Time) Motion Object Unsharpness Focal Spot Size SID (Source to Image Distance)
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Radiologic Technology 244
created: Fall 2005
OID SID SIZE SHAPE
-sharpness of detail
-degree of noise
What does they
On a radiograph it’s called ______________
MAGNIFICATION (size distortion)
TRUE DISTORTION (shape distortion)
Distortion (object & film not parallel)
Distortion of multiple objects in same image (right) due to x-ray beam not being centered over objects.
Compensate for MAG : ↑ OID by ↑ SID =
“increase SID 7” for every 1” OID”
In terms of recorded detail and magnification, the best image is produced with a small OID and a large SID.
Film is designed to be sensitive to the color of light emitted by the intensifying screens.
Red safe light
Speed – the response to photons
Faster response= less detail, and
less exposure (chest x-ray)
=Slower response, greater detail, more exposure (extremity)
With double emulsion – an image is created on both emulsions – then superimposed – slight blurring of edges
QUANTUM MOTTLEFilm grain, or graininess, refers to the tiny black spots that make up the visible image, one grain from each silver halide crystal exposedMORE COMMON IN CR SYSTEMS NOWNOT ENOUGH PHOTONS TO CREATE IMAGE