Grids

Question 1

Three things happen when the beam passes through the body

Answer 1

1. Pass through unaffected
2. Be absorbed
3. Interact and change direction (scatter)

Question 2

Which interaction is caused by scatter?

Answer 2

Compton interaction

Question 3

Increasing kVp, ________ Compton interactions.

Answer 3

Increases

Question 4

Interactions with the IR from scatter radiation will be of no

Answer 4

Diagnostic value

Question 5

What controls the quantity of scatter produced?

Answer 5

The patient

Question 6

The amount of scatter radiation _________ with increase in patient thickness, larger field sizes, and _________ with higher atomic number tissues/parts

Answer 6

Increases
Decreases

Question 7

Thin, flat, rectangular device made by placing a series of radiopaque lead strips side by side and separating the strips by an interspace material that is radiolucent

Answer 7

Grids

Question 8

The lead strips are very thin _____ and the interspace material is thicker and made of ______.

Answer 8

Aluminum

Question 9

When should you use a grid?

Answer 9

Body part thickness exceeds 10cm
kVp is above 60

Question 10

When was the grid invented and who invented it?

Answer 10

1913
Gustav Bucky

Question 11

The lead strips are

Answer 11

Radiopaque

Question 12

The radiopaque strips are made of

Answer 12

Lead

Question 13

The interspace strips are

Answer 13

Radiolucent

Question 14

What are the interspace strips made of

Answer 14

Aluminum of plastic fiber

Question 15

The function of the grid involves the selection of

Answer 15

Material
Grid ratio
Grid frequency

Question 16

the ratio of the height of the lead strips to the distance between the strips

Answer 16

Grid ratio

Question 17

What is the grid ratio formula?

Answer 17

H/distance

Question 18

_____ grid radios allow less scatter radiation to pass through to the IR

Answer 18

Higher

Question 19

Number of grid lines per inch or centimeter

Answer 19

Grid frequency

Question 20

By combining the info from grid ratio and grid frequency, the radiographer can determine the total _____ of lead in a grid.

Answer 20

Quantity

Question 21

Grids with higher grid frequency have _______ lead strips

Answer 21

Thinner

Question 22

______ content of the grid is what determines the grid’s efficiency at cleaning up scatter and improving contrast.

Answer 22

Lead

Question 23

Lead strips running in only one direction

Answer 23

Linear grids

Question 24

Lead lines running at right angles to one another

Answer 24

Criss-crossed or cross hatched grids

Question 25

Linear grids are most common due to

Answer 25

Tube angulation

Question 26

Angulation across the long axis would result in the beam hitting the lead strip and getting absorbed. This is known as _______.

Answer 26

Grid cutoff

Question 27

Lead and interspace material run parallel to one another

Answer 27

Parallel grid

Question 28

Lead lines are angled to match the angle of divergence of the primary beam

Answer 28

Focused grid

Question 29

If the lines of a focused grid were extended, the strips would intersect along a line in space known as ________

Answer 29

Convergence line

Question 30

________ grids also allow more transmitted photons to reach the IR

Answer 30

Focused

Question 31

Parallel grids are best used with ____ SID’s.

Answer 31

Long