Chapter 12 Assignment Flashcards
The principle reason for using a digital radiographic grid during a diagnostic examination is:
a.) reduction in the amount of secondary scatter reaching the image receptor
b.) increase in intensity of the radiation reaching the image receptor
c.) the reduction of the amount of backscatter radiation reaching the IR
d.) reduction of patient exposure
a.) reduction in the amount of secondary scatter reaching the image receptor
The reduction of secondary radiation reaching the IR can be accomplished by using:
(choose all that apply)
a.) an increase OID
b.) digiral radiographic grids
c.) beam limiting devices
a.) an increase OID
b.) digital radiographic grids
c.) beam limiting devices
what is Grid Ratio formula?
r= h/D
Which type of grid pattern wil result in a radiograph with the least amount of primary beam cutoff?
a.) focus grid
b.) parallel grid
c.) crossed grid
d.) rhombic grid
a.) focus grid
The principle function of the potter bucky diaphragm (bucky tray), is to provide a simple means for moving the imaging device without moving the patient. The bucky tray also serves to:
a.) reduce the field of view
b.) reduce the exposure to patients
c.) move the grid during the exposure
d.) reduce the amount of backscattered radiation produced
c.) move the grid during the exposure
Which of the following focus grids will allow for the greatest amount of centering and distance latitude?
a.) 6:1
b.) 8:1
c.) 12:1
d.) 16:1
a.) 6:1
In order to select a grid with the proper ratio which of the following factors should be considered? select all that apply
a.) positioning latitude
b.) degree of cleanup
c.) kv range
a.) positioning latitude
b.) degree of cleanup
c.) kv range
In order to avoid the appearance of grid lines using a moving grid, the bucky tray motion must commence:
a.) before exposure begins
b.) after exposure begins
c.) grid movement is not necessary
a.) before exposure begins
A grid is constructed with all the grid strips running parallel to each other is an example of:
a.) linear focus grid
b.) linear parallel grid
c.) cross hatched grid
b.) linear parallel grid
The distance at which a focus grid can be used is most clsely related to the:
a.) grid ratio
b.) grid frequency
c.) convergence line
d.) interspacing material
c.) convergence line
If a grid ratio was increased and no technical changes made, the resulting radiograph would show an increase in :
a.) gray scale shifting
b.) magnification
c.) image contrast
d.) shape distortion
c.) image contrast
The use of high ratio grids are most often recommended when:
a.) a high kv technique must be employed
b.) a number of different source to image receptor distances are required
c.) the dose reduction to the patient is of great concern
d.) a considerable degree of off centering may be required
a.) a high kv technique must be employed
In a modern 8 to 1 focus grid, the majority of scatter reduction resluts from the:
a.) lead grid strips
b.) aluminum grid strips
c.) Lead interspacing material
d.) aluminum interspacing material
a.) lead grid strips
The amount of primary beam cutoff by grids can be greatly reduced by employing a:
a.) crossed grid
b.) focused grid
c.) linear grid
d.) Moving grid
b.) focused grid
A type of grid in which the grid strips are situatied parallel to the divergetn rays of the xray beam is termed a:
a.) stationary grid
b.) parallel grid
c.) linear grid
d.) focused grid
d.) focused grid
The ability of a grid to absorb scatter radiation after it exits the patient is termed:
a.) contrast improvement factor
b.) grid efficiency
c.) grid uniformity
d.) grid sensitivity
b.) grid efficiency
An increase in the amount fo scatter pickup or contrast improvement factor is associated with an: choose all that apply
a.) increase grid ratio
b.) increase in grid frequency
c.) decrease in grid ratio
a.) increase grid ratio
b.) increase in grid frequency
When a focus type grid is used, the appearance of grid cutoff is not associated with which of the following:
a.) tube angulation directed along the grid strips
b.) a central ray that is directed to the side of the grid
c.) the use of the wrong SID
d.) the excessive tilting of the grid to the tube
a.) tube angulation directed along the grid strips
The mas most often credited with the construction of the first practical digital grid is:
a.) W. K. Roentgen
b.) H. potter
c.) G. Bucky
d.) J.P focus
c.) G. Bucky
The main advantage of a moving grid compared to a stationary grid of the same ratio and frequency: choose all that apply
a.) the ability to reduce the appearance of grid lines
b.) the ability to reduce the amount of grid cutoff
c.) the ability to employ larger tube angulations
a.) the ability to reduce the appearance of grid lines
Which of the following focus grids would be associated with the least amount of centering and distance latitudes?
a.) 6 to 1 linear
b.) 8 to 1 linear
c.) 13 to 1 linear
d.) 16 to 1 linear
d.) 16 to 1 linear
The appearance of grid lines, when a focused grid is used in a bucky tray, is not likely in which of the following situations?
a.) when an excessive SID is used
b.) when the grid is stopped after the exposure commences
c.) when the grid begins to move before the exposure commences
d.) when the grid is not centerd to the tube
c.) when the grid ebgins to move before the exposure commences
Contrast improvement that can be obtained with a particular grid is dependent on: choose all that apply
a.) kvp employed
b.) size of the field
c.) patient thickness
a.) kvp employed
b.) size of the field
c.) patient thickness
