Chapter 3: Interaction Of Radiation With Matter

Question 1

Average number of primary and secondary ion pairs produced per unit lenth of the charged particle’s path

Answer 1

Specific ionization

Question 2

Transfer of some of the incident particles energy to electrons in the absorbingmaterial promoting them to electron orbits father from the nucleus

Answer 2

Excitation

Question 3

The electron will return to a lower energy level with the emission of the excitation energy in the form of electromagnetic radiation or Auger electrons

Answer 3

De excitation

Question 4

Result of ionization, consisting of an ejected electron and positively charged atom

Answer 4

Ion pair

Question 5

Ejected electrons possess sufficient energy to produce further ionizations (definition)
What do you call these electrons

Answer 5

Secondary ionization

Delta rays

Question 6

Defined as the distance the particle travels

Answer 6

Path length

Question 7

Defined as the depth of penetration of the particle in matter

Answer 7

Range

Question 8

Measure of the average amount of energy deposited locally in the absorber per unit path length

Answer 8

Linear energy transfer

Question 9

Refers to an interaction that deflects a particle or photon from its original trajectory

Answer 9

Scattering

Question 10

A scattering event in which the total kinetic energy of the colliding particles is unchanged

Answer 10

Elastic

Question 11

When scattering occurs with a loss of kinetic energy

Answer 11

Inelastic

Question 12

Radiation emission accompanying electron deceleration

Answer 12

Bremsstrahlung

Question 13

4 major types of xray and gamma ray photon interaction

Answer 13

Rayleigh scattering
Compton scattering
Photoelectric absorption
Pair production

Question 14

Incident photon interacts with and excites the TOTAL ATOM as opposed to individual electrons

Answer 14

Rayleigh Scattering

Question 15

Occurs mainly with very low energy xrays such as those use in mammography (15 to 30 keV)

Answer 15

Rayleigh Scattering

Question 16

Does ionization occur in Rayleigh Scattering

Answer 16

No

Question 17

Also referred to as coherent or classical scattering

Answer 17

Rayleigh scattering

Question 18

Also called inelastic or non classical scattering

Answer 18

Compton scattering

Question 19

Predominant interaction of xray and gamma ray photons in diagnostic energy range with soft tissue

Answer 19

Compton scattering

Question 20

All of the incident photon energy is transferred to an electron, which is ejected from the atom.

Answer 20

Photoelectric absorption

Question 21

This xray interaction improves attenuation between tissues with slightly different atomic numbers, thereby improving image contrast

Answer 21

Photoelectric effect

Question 22

Xray or gammay ray interacts with the electric field of the nucleus of an atom

Answer 22

Pair production

Question 23

is the removal of photons from a beam of xrays or gamma rays as it passes through matter

Answer 23

Attenuation

Question 24

Fraction of photons removed from a monoenergetic beam of xrays or gamma rays per unit thickness of material

Answer 24

Linear attenuation coefficient

Question 25

Defined as the thickness of material required to reduce the intensity of an xray or gamma ray beam to one half of its initial value.

Answer 25

Half value layer

Question 26

Refers to an experimental configuration that is designed to exclude scattered photons from being measured by the detetctor

Answer 26

Narrow beam geometry

Question 27

The beam is sufficiently WIDE that a substantial fraction of scattered photons remain in the beam

Answer 27

Broad beam geometry

Question 28

This is an ESTIMATE of PENETRATION power of the xray beam

Answer 28

Effective energy

Question 29

The sift of the xray spectrum to higher effective energies as the beam transverses matter

Answer 29

Beam hardening

Question 30

Kinetic energy released in matter

Defined at th ekinetic energy transferred ri charged particlesby indirectly ionizing radiration per unit mass

Answer 30

Kerma

Question 31

Number of photons or particles passing through a unit cross sectional area

Answer 31

Fluence

Question 32

Fluence rate + unit area per unit time

Answer 32

Flux

Question 33

Amount of energy passing through a unit cross sectional area

Answer 33

Energy fluence

Question 34

Defined as the energy imparted by ionizing radiation per unit mass of irradated materal

Answer 34

Absorbed dose

*this is designed for all types of ionizing radiation

Question 35

Amount of electrical charge produced by ionizing electromagnetic raidation per mass

Answer 35

Exposure

Question 36

Total amount of energy deposited in matter

Product of the dose and the mass over which the energy is imparted

Answer 36

Imparted energy

Question 37

To modify the dose to reflect the relative effective of the type of radiation in producing biologic damage

Answer 37

Radiation weighing factor

Question 38

Product of the absorbed dose and the radiation weighing factor

Answer 38

Equivalent dose

Question 39

The sum ofthe products of the equivalent dose to each organ or tissue irradiated and the corresponding weighting factor for that organ or tissue is called…

Answer 39

Effective dose

Question 40

Particle interaction, where energy transferred to an e- < binding energy
Results in the release of EM radiation/Auger electrons

Answer 40

Excitation

Question 41

Particle interaction where in the transferred energy > binding energy
Results in an ion pair (Ejected e- and atom+) -emission-> Delta rays

Answer 41

Ionization

Question 42

Defined as the probability distribution of xray photons as function of photon energy (keV)

Answer 42

Bremsstrahlung Radiative Interaction

Question 43

calculated through mass energy TRANSFER coefficient

Answer 43

KERMA (Kinetic Energy Releases in Matter)

Question 44

calculated from mass energy ABSORPTION coefficient

Answer 44

Absorbed Dose