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WorksheetsMI237 Unit 1 Scatter Control 2024
Total questions: 37
Worksheet time: 20mins
Compton interaction results in a significant radiation dose to the:
patient
radiologic technologist
Photons scattered through Compton interaction have:
lower energy and longer wavelengths
higher energy and shorter wavelengths
lower energy and shorter wavelengths
higher energy and longer wavelengths
Where is scatter produced?
at the anode of the xray tube
in the tissues of the patient
in the layers of the image receptor
at the shutters of the collimator box
Which of the following two factors affect scatter production? (Select 2)
Amount of tissue exposed
mAs
kVp
Amount of tube current
What affect does increased beam restriction have on scatter?
Increased scatter production
decreased scatter production
Which of the following controls scatter production the most?
beam restriction
grids
filtration
digital processing
Which of the following occurs with increased beam restriction?
the field size gets smaller
the amount of scatter increases
the contrast is reduced
the occupational exposure increases
If a lack of photons occur due to significant increased beam restriction, what would best remedy the receptor exposure?
increase mAs
increase kVp
Decrease mAs
Decrease kVp
This is an image of:
positive beam limiters
aperture diaphragms
cones
cylinders
Which of the following is a disadvantage of aperture diaphrams, cones, and cylinders?
fixed field sizes
increased patient dose
limited scatter absorption
Which of the following two options are recommendations for using a standard grid? (Select 2)
part size >10cm
part size >18cm
>60kVp
>80kVp
What is the equation for grid ratio?
height of lead/width of interspace material
height of lead/width of lead
height of lead x width of lead
width of interspace/height of lead
Which of of the following occurs with an increase in grid ratio?
decreased photon absorption
increased photon absorption
decreased scatter production
increased scatter production
Which two of the following are consequences of maintaining receptor exposure when using a grid? (select 2)
mAs increases
mAs decreases
pt dose increases
pt dose decreases
Which of the following grid ratios would clean up the most scatter?
5:1
8:1
12:1
16:1
When maintaining receptor exposure, which of the following grid ratios would cause the greatest patient dose?
5:1
8:1
12:1
16:1
Which two of the following choices are true regarding focused grids? (select 2)
Specific SIDs must be used
lead strips are angled
lead strips are cross hatched
Specific focal spot sizes must be used
The grid radius is determined by the:
grid ratio
grid frequency
imaginary lines extending from canted strips to a convergence point
imaginary lines extending from the surface of a parallel grid
This is an example of which of the following types of grids?
short dimension
long dimension
cross hatched
focused
What is the grid conversion factor for a 6:1 grid?
1
2
3
4
When using a parallel or focused grid, a tube angle can only be applied if angled:
parallel to the length of the strips
perpendicular to the length of the strips
What term is used to describe a decrease in receptor exposure because of misalignment of a grid?
grid failure
grid cut off
grid termination
grid off put
Significant grid cut off on 2 outer edges depicted here is most likely caused by which of the following errors?
an upside down focused grid
an off level grid
an off center grid
an off angle grid
Which type of grid provides more leeway for misalignment and centering errors that may occur during portable imaging situations?
cross hatch
5:1
8:1
16:1
Which of the following is the greatest advantage of using a virtual grid over a standard grid?
increased scatter absorption
decreased pt dose
increased grid ratios
decreased scatter production
Which of the following mimics the use of a grid?
line focus principle
air gap technique
space charge effect
anode heel effect
When increasing the OID to decrease scatter reaching the IR, what can be done to correct for distortion?
increase SID
decrease kVp
increase tube angle
decrease focal spot size
What is the intensity of a scattered photon 1 meter from the pt?
1% of the primary beam
1/1000 of the primary beam
10% of the primary beam
1/100 of the primary beam
What is the minimum lead equivalency of protective aprons and thyroid shields? (NCRP102)
0.5mm Pb
0.25mm Pb
2.5mm Al
0.35mm Al
To best protect against scatter during portable radiography, a technologist should stand 90 degrees to the path of the beam and at a minimum of what distance?
6 inches
2 feet
2 meters
12 inches
Where would you stand during fluoroscopy for lowest occupational dose?
head of table
foot of table
90 degrees perpendicular to table
behind secondary barrier
Which of the following situations would give the radiographer the highest dose?
Carm tube angled toward operator
Fluoro room standing at side of table
Carm II on top
Fluoro room behind control console or mobile barrier
What is meant by an off level grid error?
tube angled against strips
grid not flat
wrong focus distance used for grid
upside down grid
The primary effect of scatter radiation on radiographic image quality is decreased:
Receptor Exposure
Contrast
Brightness
Spatial Resolution
Which of the following statements is accurate regarding focused grids?
Lead strips are angled to match the divergence of the x-ray beam
Lead strips are perpendicular to each other
Two sets of lead strips are present at 90 degrees to each other
Lead strips are closer together in focused grids
Which of the following exam scenarios would utilize a moving grid?
Portable AP Erect Chest
Tabletop hand
Tabletop ankle
Supine femur with table bucky
What type of grid allows for a wide range of focal distances?
Multi-focus
Long range
Short range
Lattice
