Quick Review Flashcards
What concept controls the film’s overall darkness?
Density
What measurement primarily controls density?
mAs (mA X s)
What effect does increased mA, s, and/or mAs have on density?
Increased density
What kind of patient will require more mAs and why: smaller or larger patient?
Larger patient due to increase in tissue thickness
What effect does an increase in distance (SID/FFD) have on density?
Decreased density (rule of 3)
What effect does increased kVp have on density?
Increased density (due to increased scatter which adds more gray to the film therefore increasing overall darkness)
Which kind of screen requires more mAs to make them fluoresce: 200 speed or 400 speed?
200 speed (smaller)
What is the purpose of a grid?
Clean up scatter
When using a grid, what measurement must be increased and why?
mAs because the grid takes away levels of scatter (grays) thus takes away some color which takes away darkness
Why do we not increase kVp when using a grid?
Increases scatter production (which is what we are trying to get rid of)
What effect does both too much developer and being in the developer for too long have on density?
Increased density
What is the purpose of filtration?
Even out radiographic density
When x-raying a part with two different thicknesses, a filter is used to cover what part?
Thin part
What is the term for the varying shades of gray on a radiograph?
Contrast
What measurement primarily controls contrast?
kVp
What are the functions of kVp?
1 power in the x-ray bundle
2 brings anatomy to the film
3 causes scatter
Which scale is associated with low contrast and is a result of using high kVp: long or short scale?
Long
Which scale is associated with high contrast and is a result of using low kVp: long or short scale?
Short
Which presents as a very black and white film: short or long scale?
Short
Which presents as a very dull, gray film: short or long scale?
Long
What structure is used when tissue thickness is 11 cm or greater to prevent scatter?
Grid
Altering what measurement is required when a grid is used to remove scatter?
mAs
What kind of grid ratio causes more scatter: low or high?
High grid ratio
What term is used to explain how well represented the anatomy is radiographically aka crispness of the film?
Detail
At what distance do we see the best detail?
SID/FFD of 72”
What is the issue with the tube being close to the object?
Magnification (less definition)
What is the ideal OFD to prevent magnification and destruction of detail?
Have part as close to film as possible
How does density affect detail?
Increased density = decreased detail (film will be too dark to see anatomy
Which scale decreases detail: short or long scale?
Long scale (too gray to see anatomy)
Would increased or decreased developer lead to decreased detail?
Increased developer (because it increases density and visibility)
How can tube tilt affect detail?
Wrong tube tube results in loss of detail (or not using tube tilt when required)
