Ch12: Beam Restriction Flashcards
What are the advantages of beam restriction?
decreases scatter radiation
decreases patient dose
increases contrast
increases image quality
What are the disadvantages of beam restriction?
increase quantum noise
decreases the amount of photons hitting the IR
How can patient exposure be reduced if exposure factors are being increased?
What are the advantages of using a grid?
What are the disadvantages of using a grid?
How can you adjust the field size to decrease the amount of scatter radiation produced?
decreasing the xray field size
increase collimation/beam restriction
What is not a type of beam restrictor?
aperture diaphragm
positive beam-limiting device
cylinder
lead shield
lead shield
T/F as collimation decreases, the quantity of scatter radiation decreases.
False
scatter radiation would increase
What type of beam-restricting device provides the most flexibility in adjusting the xray field size?
cylinder
aperture diaphragm
collimator
cone
What describes the number of lead lines per unit length?
grid frequency
grid pattern
grid convergent point
grid ratio
a radiographic image was created using a 12:1 grid and 70 kvp at 10 mas. What exposure technique change would maintain a similar exposure to the image receptor when converting to a 6:1 ratio grid?
81 kvp at 5 mas
70 kvp at 16.7 mas
70 kvp at 6 mas
60 kvp at 20 mas
what type of grid has lead strips running parallel to the long axis of the grid?
focused
short dimension
cross hatched
long dimension
angling the xray tube along the long axis of a crossed grid would result in:
increased scatter absorption
grid cutoff
moire effect
lateral decentering
for the air gap technique to be effective in reducing scatter radiation reaching the image receptor, what must be increased?
SID
focal spot size
kvp
OID
With exposure technique compensation, ____ the grid ratio will ____ patient radiation exposure.
decreasing, increase
increasing, decrease
increasing, increase
decreasing, will not affect
