Density Flashcards
X-rays that penetrate the body (black on the image)
Radiolucent
What is density?
Overall blackness on a radiographic film
X-rays that are absorbed in the body (white on the image)
Radiopaque
Is density directly or inversely controlled by mAs?
Directly
If you double mAs, what happens to density?
It doubles
If mAs is halved, what happens to density?
It’s halved
What 3 words could describe mAs?
Current
Number
Quantity
What is the major controlling factor for density?
mAs
If mAs increases, what happens to density?
Density increases
How much does mAs have to be increased in order to see a difference in density on the film?
30%
2 ways to double density
Double mAs
Increase kVp by 15%
If you increase kVp by 15%, what should you do with mAs?
Why?
Decrease mAs by 1/2 it’s original value
To result in the same density
If you decrease kVp by 15%, what should you do with mAs?
Increase mAs by 2 times
Increasing kVp by 15% is equal to _________.
Doubling mAs
Increasing kVp and reducing mAs will do what?
Reduce patient dose
Help reduce motion on image
If you increase beam restriction/collimation, what happens to density?
Why?
Decreases
Reduction of scatter produced
If you increase body habits, what happens to density?
Why?
Decreases
More attenuation and absorption
If you increase screen speed, what happens to density?
Why?
Density increases
Increased size of phosphors
If you increase grid ratio, what happens to density?
Why?
Density decreases
Grids absorb scatter
Decreasing kVp by 15% is the same as ____________.
Dividing mAs in half
increasing kVp & reducing mAs will do what?
reduce patient dose
reduce motion on the image
if you increase beam restriction, what happens to density?
why
density decreases
reduction of scatter produced
if you increase body habitus, what happens to density?
why?
density decreases
more attneuation & absorption
if you increase screen speed, what happens to density?
why?
density increases
increased size of phosphors
