10. Interaction of Radiation with Matter

Question 1

is defined as the rate of emitted energy from unit surface area through unit solid angle

Answer 1

Radiation Intensity

Question 2

The total reduction in the number of x-rays remaining in an x-ray beam after penetration through a given thickness of tissue

Answer 2

Attenuation

Question 3

is the product of absorption and scattering

Answer 3

Attenuation

Question 4

is an all-or-none condition for an x-ray

Answer 4

Absorption

Question 5

is a quantity that characterizes how easily a material or medium can be penetrated
by a beam of light, sound, particles, or other energy or matter.

Answer 5

Attenuation Coefficient

Question 6

The attenuation coefficient is also called

Answer 6

linear attenuation coefficient,
narrow beam attenuation coefficient, or
absorption coefficient

Question 7

means that the beam is quickly “attenuated” (weakened) as it passes through the medium

Answer 7

large attenuation coefficient

Question 8

means that the medium is relatively transparent to the beam

Answer 8

small attenuation coefficient

Question 9

The difference in x-ray interaction

Answer 9

Differential Absorption

Question 10

Increases as the kVp is reduced

Answer 10

Differential Absorption

Question 11

Differential absorption and attenuation of the x-ray beam depend on the following factors:

Answer 11

o The atomic number (Z) of the atoms in tissue.
o The mass density of the atoms in tissue.
o The x-ray energy.

Question 12

The Thickness of an absorber needed to reduce the intensity of the x-ray beam into half of its original value

Answer 12

Half-Value Layer (HVL)

Question 13

The fraction of the beam that penetrates the block

Answer 13

Transmission Fraction

Question 14

TF = 2^–n

Where n =

Answer 14

block thickness/half value thickness

Question 15

X-ray Interaction Mechanism

Answer 15

• Coherent Scattering
• Compton Scattering
• Photoelectric Effect
• Pair Production
• Photodisintegration

Question 16

Energies below approximately 10 keV

Answer 16

Coherent Scattering

Question 17

Coherent Scattering sometimes called

Answer 17

Classical scattering or Thompson scattering, Rayleigh Scattering

Question 18

No ionization

Answer 18

Coherent Scattering

Question 19

is an interaction between low-energy x-rays and atoms.

Answer 19

Classical scattering

Question 20

The x-ray loses no energy but changes direction slightly.

Answer 20

Classical scattering

Question 21

The wavelength of the incident x-ray is equal to the wavelength of the scattered x-ray

Answer 21

Classical scattering

Question 22

the incident x-ray interacts with an outer shell electron and ejects it from the atom,
thereby ionizing the atom

Answer 22

Compton Effect

Question 23

The ejected electron is called a

Answer 23

Compton electron or a secondary electron

Question 24

occurs between moderate-energy x-rays and outer-shell electrons.

Answer 24

Compton Effect

Question 25

It results in ionization of | the target atom, change in direction, and reduction in x-ray energy.

Answer 25

Compton Effect

Question 26

the wavelength of the scattered x-ray is greater than that of the incident x-ray.

Answer 26

Compton Effect

Question 27

The x-ray continues in a different direction with less energy

Answer 27

Compton Effect

Question 28

The probability of the _______ is inversely proportional to x-ray energy (1/E) and independent of atomic number

Answer 28

Compton Effect

Question 29

Interacts with inner shell electrons

Answer 29

Photoelectric Effect

Question 30

X-rays are absorbed

Answer 30

Photoelectric Effect

Question 31

The electron removed from an atom is called

Answer 31

photoelectron

Question 32

is total x-ray absorption

Answer 32

Photoelectric Effect

Question 33

The probability of the ________ is inversely proportional to the third power of the x-ray energy (1/E)^3

Answer 33

Photoelectric Effect

Question 34

``` The probability of _______ is directly proportional to the third power of the atomic number of the absorbing material (Z^3) ```

Answer 34

Photoelectric Effect

Question 35

Incident electron interacts with the nuclear field

Answer 35

Pair Production

Question 36

The interaction between the x-ray and the nuclear field causes the x-ray to disappear, and in its place, two electrons appear, one positively charged (positron) and one negatively charged (electron)

Answer 36

Pair Production

Question 37

positively charged

Answer 37

positron

Question 38

negatively charged

Answer 38

electron

Question 39

Occurs above 1.02 MeV

Answer 39

Pair Production

Question 40

Occurs with x-ray energies above 10 MeV

Answer 40

Photodisintegration

Question 41

The nucleus is raised to an excited state and instantly emits a nucleon or other nuclear fragment

Answer 41

Photodisintegration

Question 42

it means there is decrease in x-ray quantity or the amount of the x-ray beam

Answer 42

Attenuation

Question 43

The ______ the linear attenuation coefficient, the ______ capability of the material to absorb radiation. Organizing radiation.

Answer 43

greater, | greater

Question 44

type of interaction occurs when there is no interaction

Answer 44

Excitation

Question 45

the incoming electron does not possess enough energy to remove any electron the atom; the atom will just raise to the higher energy state and eventually return to its normal state; in the process,

Answer 45

Excitation

Question 46

In Excitation, ______ is being emitted but there is no removal of electrons involve.

Answer 46

Infrared Radiation

Question 47

The incident photon strikes the atom but its energy is not enough it is deflected; atoms are just trembles or shaken and eventually return to normal

Answer 47

Classical scattering

Question 48

Occurs when the energy of the incoming electron is about approximately 20 or 27 up to 37 kEv

Answer 48

Compton Effect

Question 49

The energy of the incoming electron is not that much but it’s enough to produce ionization in outer shell electrons; the ejected electrons is what we call the ______, it will be scattered. If the scattered electrons still have enough energy, it will continue ionizing others till the energy is gone, just like the billiard-ball analogy.

Answer 49

Compton Electron

Question 50

Compton effect SI Unit:

Answer 50

kEv

Question 51

X-rays are scattered

Answer 51

Compton Electron

Question 52

Interacts with outer shell

Answer 52

Compton Electron

Question 53

If you increased the kVp, the probability of Compton effect will

Answer 53

decrease

Question 54

The incoming electron will remove the inner shell electron; the ejected electron is known as PHOTOELECTRON, if it has enough energy, it will ionize other atom, it will strike and eject other electron, the second electron that will be ejected is what we called

Answer 54

Auger Electron

Question 55

In the photoelectric effect once the inner shell electrons have been ejected; there are 2 possible ways:

Answer 55

1) electrons drops the fill of vacancy of the emitting photon or 2) the energy is transfer to outer electron and ejects it

Question 56

The higher the atomic number the _____ the chance of having photoelectric effect; _____ chance of having an absorption.

Answer 56

greater, | greater

Question 57

Incoming electron interacts with the nuclear field; the atom will be divided into a positive charge and negative charge both of the particles possess 0.511 MeV a total of 1.02 MeV, in order to create pair production, the energy of the projectile electron must be equal or greater than 1.02 MeV.

Answer 57

Pair Production

Question 58

does not occur in diagnostic radiography, it only occurs in PET imaging or nuclear medicine

Answer 58

Pair Production

Question 59

are the only interaction contributes in diagnostic radiography

Answer 59

Photoelectric Effect and Compton Effect

Question 60

Occurs in nuclear bomb explosion

Answer 60

Photodisintegration

Question 61

Incoming electron interacts with the nucleus and disappear in nuclear fragments and scattered away

Answer 61

Photodisintegration

Question 62

Indicates the ability of material to attenuate

Answer 62

Linear Attenuation Coefficient

Question 63

is the total reduction of | radiation intensity

Answer 63

Attenuation

Question 64

The type of interaction that will occur in coherent scattering is

Answer 64

Excitation

Question 65

Does not contribute to the formation of the image

Answer 65

Coherent Scattering

Question 66

is not capable of removing the electron in the shells

Answer 66

Low energy

Question 67

99% of coherent scattering is

Answer 67

heat or infrared radiation

Question 68

The more the energy is decreased, photoelectric effect ______

Answer 68

increases

Question 69

The term “_____” is used because the types of substance is an aggregation of different types of element.

Answer 69

Effective

Question 70

Fat effective atomic number

Answer 70

6.3

Question 71

Soft tissue effective atomic number

Answer 71

7.4

Question 72

Lung effective atomic number

Answer 72

7.4

Question 73

Bone effective atomic number

Answer 73

13.8

Question 74

Air effective atomic number

Answer 74

7.6

Question 75

Iodine effective atomic number

Answer 75

53

Question 76

Barium effective atomic number

Answer 76

56

Question 77

Concrete effective atomic number

Answer 77

17

Question 78

Molybdenum effective atomic number

Answer 78

42

Question 79

Tungsten effective atomic number

Answer 79

74

Question 80

Lead effective atomic number

Answer 80

82

Question 81

Rhodium atomic number

Answer 81

45

Question 82

Rhenium atomic number

Answer 82

75

Question 83

Calcium atomic number

Answer 83

20

Question 84

Hydrogen K-shell electron binding energy

Answer 84

0.02

Question 85

Carbon K-shell electron binding energy

Answer 85

0.3

Question 86

Nitrogen K-shell electron binding energy

Answer 86

0.4

Question 87

Oxygen K-shell electron binding energy

Answer 87

0.5

Question 88

Aluminum K-shell electron binding energy

Answer 88

1.6

Question 89

Calcium K-shell electron binding energy

Answer 89

4.1

Question 90

Molybdenum K-shell electron binding energy

Answer 90

19

Question 91

Rhodium K-shell electron binding energy

Answer 91

23

Question 92

Iodine K-shell electron binding energy

Answer 92

33

Question 93

Barium K-shell electron binding energy

Answer 93

37

Question 94

Tungsten K-shell electron binding energy

Answer 94

69

Question 95

Rhenium K-shell electron binding energy

Answer 95

72

Question 96

Lead K-shell electron binding energy

Answer 96

88