6: Image Quality Flashcards
A film with a large/wide latitude will typically have a…
High speed compared to low latitude film
The sharpness of a radiographic image’s outline (abruptness of density transition) is termed radiographic:
Definition
A long dark line running through a processed radiograph can be due to what fault?
A scratch in the lead screen
Sensitivity depends on what?
Contrast and definition
What is subject contrast?
Ratio intensities transmitted by 2 selected portions of a specimen of varying thicknesses/densities
A high contrast film will produce what type of latitude?
Narrow
Increasing the energy will do what to subject contrast?
Somewhat reduce it HOWEVER it may also widen latitude slightly
What do high densities look like on a characteristic curve?
Slope is steeper - film is more sensitive, requires less exposure
Max contrast of films used with lead foil screens is at a density of about what?
2.0
Greatest sensitivity when exposure provides this density
On a DIN (Deutsch Industrie-Norm), what indicates image quality?
The thinnest wire
ASTM “A, B, C & D” penetrameters are each a different wire diameter for different ____________.
Material types
What checks precision of a densitometer?
Calibrated density strips
Typically ranging from 1.0-4.0
How often should densitometers be compared the the density strips?
Every 90 days
IQI’s or penetrameters are made of what?
The same or similar material as the specimen being radiographed
The amount of film darkening in radiography is called what?
Density
