Chapter 5

Question 1

Two factors affecting amount of scatter reaching IR:
A. kVp=controls __1__ - Increased kVp&raquo_space; Increased __2__
B. Volume of tissue - Increased tissue thickness&raquo_space; Increased __3__.

Answer 1

1. Scatter
2. Scatter
3. Scatter

Question 2

As collimation decreases (__1__ field size)=__2__ production of scatter and __3__ pt. doses it’s decreased contrast/__4__ density.

Answer 2

1. Increased
2. Increased
3. Increased
4. Increased

Question 3

As collimation increases (__1__ field size)=__2__ production of scatter and __3__ pt. dose with increased contrast/__4__ density.

Answer 3

1. Decreased
2. Decreased
3. Decreased
4. Decreased

Question 4

First step in pt. protection?

Answer 4

OPTIMUM COLLIMATION

Question 5

Significant COLLIMATION may require an increase in _______

Answer 5

MAS

Question 6

There is _____ unsharpness on the anode side of the tube.

Answer 6

Less

Question 7

Simplest type of collimator. Piece of lead with a hole in it. NOT variable and not used often.

Answer 7

Aperture Diaphragm

Question 8

Cone=shaped like a __1__ and correlates to divergent of beam.
Cylinder=shaped like a __2__ and can extend down. Used mostly for __3__, though not used much anymore. ___4___ are better than __5__. Are __6__ variable.

Answer 8

1. Megaphone
2. Tube
3. Skull work
4. Cylinders
5. Cones
6. NOT

Question 9

Best type of variable beam restricting device. Two sets of adjustable lead shutters and a light source for centering.

Answer 9

Box-Type Collimator

Question 10

NCRP says COLLIMATION must be wishing ______ of the SID

Answer 10

+/- 2%

Question 11

Nine Penny Test checks ______.

Answer 11

COLLIMATION

Question 12

PBL/AC only used with __1__ due to sensors located there. It was a law (__2__) that all manufactured equipment have them, but no longer a law, although most manufactures still include it.
Can be overrode with a __3__, but not suggested. Can increase __4__ when it is on (“__5__”), but no larger than IR.

Answer 12

1. Bucky
2. 8/1/74-1994
3. Key
4. Collimation
5. Cone down

Question 13

__1__ invented the stationary grid in 1913. Typically used if part is __2__ or thicker & __3__ kVp or above. Does NOT decrease production of scatter, but does increase __4__ and __5__.

Answer 13

1. Gustave Bucky
2. 10cm.
3. 60
4. Contrast
5. Pt. Dose

Question 14

Grid Ratio=

Answer 14

Height of Pb strips/Distance between Pb Strips

Question 15

Interspace get materials can be __1__ or __2__.

Answer 15

1. Organic

2. Inorganic

Question 16

Scatter is a result of __1__, which results from an interaction with an __2__ Shell Electron. End Results=Compton or __3__ X Ray Photon. __4__ color on radiograph.

Answer 16

1. Compton
2. Outter
3. Weakened
4. Gray

Question 17

Grid Frequency=number of __1__ lines/inch or cm. Typically __2__ Pb lines/in (25-45 Pb/cm)

Answer 17

1. Pb

2. 60-110

Question 18

5: 1=__1__
6: 1=__2__
8: 1=__3__
12: 1=__4__
16: 1=__5__

Answer 18

1. 75%
2. 85%
3. 90%
4. 95%
5. 98%

Question 19

Grid Conversion Formula (GCF)»mAs1/__1__=__2__/__3__

Answer 19

1. MAs2
2. GCF 1
3. GCF 2

Question 20

Linear Grids=__1__ lines run in one direction only (__2__). Used most often. Can angle __3__ or __4__ but not ACROSS grid lines.

Answer 20

1. Pb
2. Head to toe
3. Cephalic
4. Caudal

Question 21

Pb lines run at right angle to one another. Cannot angle in any direction. MOST restrictive.

Answer 21

Crossed or Cross Hatch

Question 22

These grids have Pb lines parallel to one another and have no set focusing distance.

Answer 22

Parallel or Non-Focused

Question 23

Angled lead lines to use in a specific focusing distance

Answer 23

Focused Grids

Question 24

Where points converge in space from a focused grid.

Answer 24

Convergent Point

Question 25

Lay on top of IR; usually taped to IR

Answer 25

Wafer/Stationary Grid

Question 26

Who invented the moving grid?

Answer 26

Hollis Potter

Question 27

``` Movement of a moving grid includes 1. 2. 3. 4. NOT __5__ ```

Answer 27

1. Reciprocating 2. Recipromatic 3. Oscillating 4. Single-Stroke/Sling Shot 5. Elliptical (tomorrow tube travel pattern)

Question 28

Grids increase contrast by

Answer 28

Absorbing scatter

Question 29

Grids do what to pt. Dose and why

Answer 29

Increase because mAs is increased to maintain density.

Question 30

Grid to Non-Grid you _____

Answer 30

Divide

Question 31

Non grid to grid you _______

Answer 31

Multiply

Question 32

Upside down focused grid cut-off=complete __1__ grid cut off (acceptable density in center with no exposure on __2__).

Answer 32

1. Peripheral | 2. Outer Edges