Week 10 - Photographic Properties Flashcards
(34 cards)
Defined by brightness and density, visible result of an IRs response to an exposure
Brightness
Differences between brightness levels and densities, differentiates anatomic tissue
Contrast
What two factors affect radiographic visibility?
Brightness and contrast
T/F
Brightness is not related to IR exposure
True
Digital post process that produces changes in brightness
Window level
What is brightness controlled by?
The look up table (LUT)
Term used to reflect exposure to the radiographic film - the viewable result of a films response to exposure
Density
What term is interchangeable with density?
IR exposure
What is shown by an area of increased brightness on a monitor?
Decreased density on image
What is shown by an area of decreased brightness on a monitor?
Increased density on the image
ROI
Anatomic structures of interest
T/F
mAs is directly proportional to IR exposure
True
Numerical value that compares data from many images (accurately exposed images)
EXI values (exposure index)
Intensity is inversely proportional to the square of the distance
Inverse square law
T/F
For every 4-5cm of thickness, mAs should be adjusted by a factor of 2
True
*4-5cm attenuate 50%
How do grids affect exposure?
Use of a grid will reduce scatter reaching the IR, thereby reducing density/exposure
A photographic property that affects the visibility of recorded detail
Radiographic contrast
T/F
Any change that affects density will affect contrast
True
Fewer discernible shades of gray
High contrast
More discernible shades of grey
Low contrast
Fewer shades of grey levels wity greater differences between them
High contrast
Many shades of grey levels with few differences between them
Low contrast
What controlling factor Results in fewer density differences in the anatomic tissue (low/long scale contrast)
High kVp
What controlling factor results in greater density differences in the tissue (high/short scale contrast)
Low kvp
