Test 1 Ch 1-3 Flashcards
What controls Density?
mAs
# of X-rays
The amount of blackness on the image
25-30% to see difference
What controls Contrast ?
KvP
Can be described at long or short scale !!
KvP controls penetrating power
15% increase to see change
Low contrast (long scale) for chest
What is a grid used for ?
To absorb scatter
Wedge filter is used for what ?
To even out thickness/anatomy densities
What is a trough filter used for ?
Used for chest imaging
What is a boomerang filter used for?
Placed behind patient for shoulder or upper thoracic spine radiographs
What is the anode heel effect ?
Greater attenuation or absorption in thicker portion of the body part.
Cathode for thicker body part, anode on less thickness portion
What is penumbra
Unshared edges of objects
X-rays originate from ?
Or the source of X-rays come from ?
Th focal spot
Effective/equivalent dose measures in what unit ?
Sievert
Exposure unit is measured in what unit ?
R) roentgen or C/kg
Absorbed dose is measured in what unit ?
Gy or Rad
The annual dose limit for occupational workers?
50 mSv (5000mrem)
Annual dose for general public
1 mSv (100mrem)
What’s the purpose of filtration ?
To absorb low energy X-rays
Copper or aluminum is used