Chapter 3 Interaction With Matter

Question 1

The highest energy level of photons in the x-ray beam, equal to the highest voltage established across the X-ray tube?

Answer 1

Peak kilovoltage (kVp)

Question 2

The produce of electron tube current and the amount of time in seconds that the X-ray tube is activated?

Answer 2

Milliampere-second (mAs)

Question 3

Controls the quality, or penetrating power, of the photons in the X-ray beam and to some degree also affects the quantity, or numbers of photons in the beam?

Answer 3

KVp

Question 4

Is the X-ray tube current and time (in seconds) during which the X-ray tube is activated and is the main determinant of how much radiation is directed toward a patient during a pre selected X-ray exposure?

Answer 4

MAs

Question 5

Xrays are carriers of?

Answer 5

Human made electromagnetic energy

Question 6

If X-rays enter a material such as biologic tissue they may?

Answer 6

1) interact with the atoms of biological material in the patient and be absorbed
2) interact with the atoms in the biologic material and be scattered, causing some indirect transmission
4) pass through without interaction

Question 7

Happens when electromagnetic energy is transferred from the X-rays to the atoms of the patients biologic tissue?

Answer 7

Absorption

Question 8

Amount of energy absorbed per unit mass is referred to as?

Answer 8

Absorbed dose (D)

Question 9

Who also benefits when the patients dose is minimal because less radiation is scattered from the patient?

Answer 9

The radiographer

Question 10

The anode is made of tungsten or an alloy of tungsten and rhenium, these materials have?

Answer 10

High melting points
High atomic numbers (tung 74 Rhen 75)

Question 11

Permits passage of all but lowest energy components of the X-ray spectrum? Therefor acts as a filter by removing diagnostically useless, very low energy X-rays.

Answer 11

The glass window.

Question 12

A certain thickness of what is placed within the collimator assembly to intercept the emerging X-rays before they reach the patient

Answer 12

Aluminum

Question 13

Combination of the X-ray tube glass wall and the added aluminum placed within the collimator is called

Answer 13

Permanent inherent filtration of the X-ray unit.

Question 14

The filtered X-ray photon beam is collectively referred to as?

Answer 14

Primary radiation

Question 15

Photons that interact with atoms of the patient but only surrender part of their energy and will continue to exist but will emerge from the interaction at a different angle these photons are said to be?

Answer 15

Scattered

Question 16

X-rays sometimes interact with atoms of a patient such that they give up all of their energy and cease to exist, these photons are said to be?

Answer 16

Absorbed

Question 17

Photons that strike the image receptor?

Answer 17

Transmitted photons

Question 18

Are photons that have undergone either absorption or scatter and do not strike the image receptor are called?

Answer 18

Attenuated photons

Question 19

If a person were counting photons that were emitted from the X-ray tube, the total number of photons _______ would equal the total number of photons ______ plus the total number that _____ away from the IR

Answer 19

• attenuated
• absorbed
  -scattered

Question 20

If photons pass through the patient without interacting with atoms of the patient is referred to as?

Answer 20

Direct transmission photons

Question 21

If photons interact but still happen to strike the IR they are termed?

Answer 21

Indirect transmission photons

Question 22

What type of transmission is always the result of scatter?

Answer 22

Indirect transmission

Question 23

Before the four photons produced by the X-ray source enter the human tissue are referred to as?

Answer 23

Primary photons

Question 24

If only two photons emerge from the tissue and strike the X-ray detector below it they are referred to as?

Answer 24

Exit, or image formation photons

Question 25

The two photons that miss the detector are classified as?

Answer 25

Attenuated

Question 26

Refers to both absorption and scatter process that prevent photons from reaching a predefined location

Answer 26

Attenuation

Question 27

If photon 2 reaches the IR, it is part of the exit, or image formation, radiation but the bending of its path represents what?

Answer 27

Small angle scatter

Question 28

Interferes with the radiologist ability to distinguish different structures in the image?

Answer 28

Radio graphic fog

Question 29

Radiographer can confine or collimate the X-ray beam as much as possible to include only the region of interest is the best way to reduce what?

Answer 29

Fog

Question 30

Five types of interaction with X-ray radiation and matter?

Answer 30

1) coherent scattering
2) photoelectric absorption
3) pair production
4) Compton scattering
5) photodisintegration

Question 31

Of the five types of interaction between X-ray radiation and matter, only two are important in diagnostic radiology?

Answer 31

1) Compton scatter
2) photoelectric absorption

Question 32

Coherent scatter is also called what? And is simply a process of what?

Answer 32

-classic scattering
- elastic scattering
-unmodified scattering
It is a simple process that results in no loss of energy as X-rays scatter.

Question 33

Is an interaction between an X-ray photon and an inner shell electron (usually in the K or L shells).

Answer 33

Photoelectric absorption

Question 34

To dislodge an __________ from its atomic orbit, the incoming X-ray photon must be able to transfer a quantity of energy as________ or ________ that the amount of energy that holds the electron in its orbit

Answer 34

• inner-shell electron
• large or larger

Question 35

Unbound orbital electron and possesses energy equal to the energy of the incident photon minus the binding energy of its electron shell

Answer 35

Photoelectron

Question 36

Promotion of electrons from lower energy shells to higher energy shells

Answer 36

Excitation

Question 37

Complete ejection of the electron from an atom

Answer 37

Ionization

Question 38

As a result of _________ a vacancy is created in an inner shell of the target atom, for the ionized atom this represents an unstable energy situation

Answer 38

Photoelectric interaction

Question 39

Released energy is carried off in the form of a photon in photoelectric absorption called a________, because it’s energy is directly related to the shell structure of the atom from which it was emitted.

Answer 39

Characteristic photon, or characteristic X-ray

Question 40

Process of photoelectric interaction, when an inner electron removed from an atom in a photoelectric interaction, thus causing an inner shell vacancy, the energy liberated when this vacancy is filled can be transferred to another electron, instead of emerging from the atom as characteristic radiation

Answer 40

Auger effect

Question 41

What a process does not include any X-ray emission

Answer 41

Radiationless effect
Like the Auger effect

Question 42

Number of X-rays emitted per inner shell vacancy

Answer 42

Fluorescent yield

Question 43

The less a given structure attenuates radiation the _________ it’s appearance will be on a raw digital detector image, and the more it absorbs radiation, the less radiation will be received by the detector and a _________ shade of gray it will display as a raw image.

Answer 43

Brighter
Darker

Question 44

Is most likely to occur at less than 10 keV?

Answer 44

Coherent scattering