Unit 2 Review Questions

Question 1

What is the controlling factor for IR exposure?

Answer 1

mAs

Question 2

What are the influencing factors of IR Exposure?

Answer 2

-SID
-OID
-kVp
-Grid
-Beam restriction(Collimation)
-Screen factors
-Patient factors
-Anode heel effect

Question 3

What is the controlling factor for subject contrast?

Answer 3

kVp

Question 4

What are the influencing factors for subject contrast

Answer 4

-OID
-Grid
-Beam restriction(Collimation)
-Contrast media
-Patient factors
-Scatter
-Beam filtration

Question 5

“Lowest contrast”

Answer 5

-High kVp, lowest OID, Scatter

Question 6

“Highest Contrast”

Answer 6

-Low kVp, big grid ratio, collimation

Question 7

Controlling factor for spatial resolution

Answer 7

Focal spot

Question 8

Influencing factors for focal spot

Answer 8

-SID, OID, Motion

Question 9

“Best spatial resolution”

Answer 9

-Small Focal spot, long SID, short OID

Question 10

Controlling factor for size distortion

Answer 10

SID

Question 11

Influencing factor for size distortion

Answer 11

OID

Question 12

“Most size distortion” or “Most magnification”

Answer 12

-short SID, Big OID

Question 13

Controlling factor for shape distortion

Answer 13

Positioning

Question 14

What controls foreshortening?

Answer 14

Alignment of the part to the IR

Question 15

What controls elongation?

Answer 15

Alignment of CR to IR

Question 16

Shape distortion and Size distortion examples

Answer 16

-Shape: an AP axial foot with a 30 degree angle towards the heel
-Size: a PA chest at a 40” SID

Question 17

Which factor will affect the total production of scatter radiation?

Answer 17

Collimation field size

Question 18

Photoelectric effect interaction photons/electron

Answer 18

One photon in, one electron out

Question 19

Coherent scatter interaction photons

Answer 19

Photon in, scattered photon out

Question 20

Compton scatter photons and electron

Answer 20

One photon in, one electron and one scattered photon out

Question 21

The following circumstances will increase the amount of photoelectric absorption

Answer 21

-Increase in atomic number of tissue
-Increase in tissue density
-Decrease in kVp

Question 22

Circumstances that will increase the amount of Compton scatter

Answer 22

-Increase in tissue density
-Increase in volume of tissue
-Increase in kVp

Question 23

“Lowest exposure” is also known as

Answer 23

“Quantum mottle”

Question 24

“Lowest exposure” “Quantum mottle”

Answer 24

-Low mAs, low kVp, big SID, big OID, big grid ratio

Question 25

“Highest exposure”

Answer 25

-High mAs, high kVp, short SID, short OID, no grid

Question 26

Which Interactions have Ionization?

Answer 26

Photoelectric and Compton scatter

Question 27

Which interaction does not cause Ionization?

Answer 27

Coherent

Question 28

Define Ionization

Answer 28

Removing an electron from an atom

Question 29

Compton scatter increases with

Answer 29

-increased tissue density -increased tissue volume

Question 30

What is the term to describe the x-ray beam after it has been attenuated by the tissue, but before it hits the IR?

Answer 30

Remnant beam

Question 31

The chance of a Compton event occurring ________________ as photon energy increases

Answer 31

Decreases

Question 32

The chance of a Compton event occuring _________________ as atomic number of the tissue increases

Answer 32

Stays the same

Question 33

This is emitted by the electrons as they move from a higher energy state to a lower energy state in order to fill the hole after a photoelectric interaction.

Answer 33

Secondary radiation

Question 34

The force that holds electrons in orbit around the nucleus. It is also the minimum amount of energy required to remove an electron from its orbit.

Answer 34

Electron binding energy

Question 35

These reactions do not cause any ionization. They are the interactions of very low energy x-rays with atoms in which the atom is elevated to an excited state and releases a scattered photon that is also very low energy.

Answer 35

Unmodifying

Question 36

An x-ray photon that is released by an atom during the transfer of an electron from one energy shell to another

Answer 36

Characteristic photon

Question 37

The ejected electron resulting from ionization during the photoelectric effect

Answer 37

Photoelectron

Question 38

The total amount of lead content in a grid determines it?

Answer 38

Selectivity

Question 39

The collimator shutters are most often made up of

Answer 39

Lead

Question 40

The interspace material in most focused grids is made of

Answer 40

Aluminum

Question 41

If a radiographer chooses to increase the grid ratio WITHOUT proper mAs compensation, what will happen to the exposure to the IR?

Answer 41

It will decrease

Question 42

If a radiographer chooses to increase the grid ratio WITHOUT proper mAs compensation, what will happen to the patient dose?

Answer 42

It will stay the same

Question 43

Functions of x-ray beam filtration

Answer 43

Reduce patient skin dose Increase mean energy of the beam Make beam harder

Question 44

Flat sheet of metal, usually lead with a hole cut in the center and attached to the x-ray tube por

Answer 44

Aperture diaphragm

Question 45

The range of source-image distances (SID) at which the grid will not absorb significant amounts of primary radiation.

Answer 45

Focal range

Question 46

An electromagnet pulls the grid to one side and then releases it during the exposure

Answer 46

Oscillating

Question 47

A type of compensating filter used to even out densities such as in the foot or lower extremities

Answer 47

Wedge filter

Question 48

A filter that uses two or more materials that complement each other in their absorbing abilities.

Answer 48

Compound filter

Question 49

A type of compensating filter used to even out densities such as in the mediastinum

Answer 49

Trough filter

Question 50

“highest amount of scatter radiation”

Answer 50

High kVp, high mAs, high Collimation, no grid/lowest grid

Question 51

“Lowest amount of scatter radiation”

Answer 51

Low kVp, low mAs, small Collimation, biggest grid ratio

Question 52

For which interaction: Photon energy must be slightly higher than the binding energy(BE) of the electron

Answer 52

Photoelectric

Question 53

T or F: PE decreases with increased atomic #

Answer 53

False, increases

Question 54

T or F: Higher atomic density of tissue = increased chance of Photo Electric effect

Answer 54

True