Chapters 1-2: Radiation History & Radiation Physics Flashcards
Ionization, X-Radiation, X-ray Machine, Dental X-ray Production (146 cards)
1
Q
List the two types of electrical circuits used in the production of x-rays.
A
- filament circuit / low-voltage circuit
- high-voltage circuit
2
Q
Define the term: photoelectric effect
A
- one of the interactions of x-radiation with matter in which the x-ray photon collides with a tightly-bound, inner-shell electron and gives up all its energy to eject the electron from its orbit
- all of the energy of the photon is absorbed by the displaced electron in the form of kinetic energy
3
Q
What component of the tubehead surrounds and protects the x-ray tube with insulating oil?
A
the metal housing
4
Q
Define the term: ion
A
- an electrically unbalanced particle
- an atom that gains or loses an electron
5
Q
How is voltage measured in the production of x-rays?
A
kilovoltage (kVp)
6
Q
What is the term for the electrical current when the electrons flow in one steady, constant direction through the conductor?
A
direct current (DC)
7
Q
Define the term: image
A
a picture or likeness of an object
8
Q
What component of the anode in the x-ray tube us used to dissipate the heat away from the tungsten target during the production of x-ray photons?
A
the copper stem
9
Q
List the two parts of an atom
A
- nucleus
- electrons in orbit
10
Q
Which type of x-radiation is the most detrimental to humans?
A
scatter radiation
11
Q
Describe the process of the electrical current in a step-down transformer.
A
- the primary/input coil contains more wire coils that receive and energize the alternating electrical current
- this induces an electrical current in the secondary/output coil that contains less wire coils
- the resulting electrical current is directed in the x-ray tube
12
Q
Define the term: x-ray
A
a beam of energy that has the power to penetrate substances and record image shadows on image receptors
13
Q
What is the particle concept of electromagnetic radiations?
A
electromagnetic radiations are discrete bundles of energy with no mass or weight that travel in waves at the speed of light in a straight line
14
Q
Why would a substance be considered radioactive?
A
if it gives off energy in the form of particles or rays as a result of the disintegration of the atomic nuclei
15
Q
What charges are present in a neutral atom?
A
an equal number of protons (positive charges) and electrons (negative charges)
16
Q
What is the term for the path of an electrical current?
A
circuit
17
Q
What percentage of Compton scatter occurs in dental radiography?
A
62%
18
Q
How many volts are used in the high-voltage circuit?
A
65,000-100,000 V
19
Q
How many volts are used in the filament circuit?
A
3-5 V
20
Q
What is considered “the heart” of the x-ray generating system?
A
the x-ray tube
21
Q
What forms when atoms are combined?
A
molecules
22
Q
What is the wave concept of electromagnetic radiation?
A
electromagnetic radiations are waves that travel in various wavelengths at the speed of light
23
Q
Which component of the cathode in the x-ray tube produces electrons when heated?
A
tungsten filament
24
Q
Is the cathode in the x-ray tube positively or negatively charged?
A
negatively charged
25
What is radiography the science of?
the art and science of making radiographs by the exposure of an image receptor to x-rays
26
Describe the speed of x-rays.
X-rays travel at the speed of light
27
Define the term: dental radiograph
a photographic image produced on an image receptor by the passage of x-rays through teeth and related structures
28
What is the term used to measure the speed of a wave?
velocity
29
Define the term: element
substances made up of only one type of atom
30
Are frequency and wavelength conversely or inversely related?
conversely *(if the frequency of the wave is high, the wavelength will be short, and vice versa)*
31
How is the atomic number of an atom determined?
by the number of protons inside the nucleus, which equals the number of electrons outside the nucleus
32
List the four types of particulate radiation.
1. electrons *(beta particles or cathode rays)*
2. alpha particles
3. protons
4. neutrons
33
Define the term: beta particles
fast-moving electrons emitted from the nucleus of radioactive atoms
34
What is the conversion of alternating to direct current of electricity?
rectificatoin
35
What are placed in the in the x-ray tubehead to filter out the nonpenetrating, longer-wavelength x-rays from the exiting x-ray beam?
aluminum disks
36
What is the purpose of a step-up transformer?
to increase the voltage from the incoming 110-220 line voltage to the necessary 65,000-100,000 V used by the high-voltage circuit
37
Define the term: nucleus
the dense core of the atom, composed of protons and neutrons
38
How do electrons travel inside an atom?
in well-defined paths called orbits or shells
39
What is the purpose of an autotransformer?
a voltage compensator that automatically corrects minor fluctuations in the electrical current
40
Define the term: dental imaging
the creation of digital, print, or film representations of anatomic structures for the purpose of diagnosis
41
Describe the fluorescence capabilities of x-rays.
X-rays can cause certain substances to fluoresce or emit radiation in longer wavelengths
42
List the two concepts of that describe how electromagnetic radiations move through space.
1. particle concept
2. wave concept
43
What electrical charge do neutrons carry?
* no electrical charge
* they are neutral
44
Approximately how much of the x-ray energy produced at the anode is considered general radiation?
approximately 70%
45
What component of the anode in the x-ray tube serves as a focal spot for the bombarding electrons from the cathode, which will then convert those electrons into x-ray photons?
the tungsten target
46
Define the term: scatter radiation
a form of secondary radiation that is caused by an x-ray beam being deflected from its path by its interaction with matter
47
List the two components of the anode in the x-ray tube.
1. tungsten target
2. copper stem
48
What component of the x-ray tubehead aims and shapes the exiting x-ray beam?
the position-indicating device **(PID)**
49
Define the term: secondary radiation
x-radiation that is created when the primary beam interacts with matter
50
Describe the penetrating power of x-rays.
X-rays can penetrate liquids, solids, and gases, depending on the composition of that substance
51
What occurs when matter is altered?
energy
52
Where is the beginning of the electricity needed to generate x-rays created?
when the x-ray machine is turned on, the electrical current enters the control panel from the wall outlet
53
How are electromagnetic radiations arranged?
according to their energies on the electromagnetic spectrum
54
Define the term: coherent scatter / unmodified scatter
* one of the interactions of x-radiation with matter in which the path of a low-energy x-ray photon interacts with an outershell electron
* no change in the atom occurs
* scatter radiation is produced
55
What occurs when the x-rays produced inside the tube are directed to exit the tubehead?
1. the leaded-glass housing prevents the x-rays from escaping in all directions and allows a small number to pass through
2. the x-rays travel travel through th tubehead seal and the aluminum disks filter out the longer wavelengths from the x-ray beam
3. the lead collimator restricts the size of the x-ray beam
4. the remaining x-ray beam travels down the position-indicating device and exit at the opening of the tubehead
56
What component of the x-ray tubehead alters the voltage of the incoming electricity?
the transformer
57
What component of the x-ray tubehead seals in the insulating oil and filters out the x-ray beam?
the tubehead seal
58
Describe the appearance of x-rays.
X-rays are invisible
59
Define the term: ionization
* the production of ions
* the process of converting an atom into an ion, resulting in the formation of a positive atom and a dislodged negative electron
60
What are particulate radiations?
tiny particles of matter that possess mass and travel in straight lines at high speeds to create kinetic energy
61
Do shorter wavelengths carry more or less penetrating power?
more penetrating power
62
What determines the energy and penetrating power of the radiation?
wavelength
63
Define the term: molecule
two or more atoms joined together by chemical bonds
64
Which circuit in the x-ray tube is controlled by the milliamperage settings?
the filament circuit
65
Describe the wavelength of x-rays.
X-rays travel in waves and have short wavelengths with a high frequency
66
Describe the absorption properties of x-rays.
X-rays are absorbed by matter, depending on the atomic structure of that matter and the wavelength of the x-ray
67
Explain the difference between radiology and radiography.
* radiology is the overall branch of medicine that studies the uses of radiation in medicine
* radiography is the science of making physical radiographs by exposing x-rays
68
Define the term: mass number / atomic weight
the number of protons and neutrons in the nucleus of an atom
69
List the three types of transformers used to adjust the electrical current during the production of x-rays.
1. step-down transformer
2. step-up transformer
3. autotransformer
70
Describe the mass of x-rays.
X-rays have no mass
71
Define the term: wavelengths
the distance between the crest of one wave and the crest of the next
72
Define the term: frequency
the number of wavelengths that pass a given point in a certain amount of time
73
Define the term: general radiation / braking radiation / bremsstrahlung radiation
a form of radiation that occurs when speeding electrons slow down because of their interactions with the tungsten target in the anode
74
What occurs within the x-ray tube when the exposure button is pushed?
1. the high-voltage circuit is activated
2. the electrons in the cathode are accelerated across the x-ray tube to the molybdenum cup in the anode
3. the electrons are directed in a narrow beam to the tungsten target and are converted into x-ray energy and heat
4. the heat is absorbed by the copper stem and insulating oil
5. the remaining x-rays are directed into the x-ray tubehead
75
During the ionization process, what is the result of an ion pair?
* when an electron is removed from the atom
* *the atom becomes the positive ion*
* *the ejected electron becomes the negative ion*
76
Describe the effect of x-rays on an image receptor.
X-rays can produce an image on an image receptor
77
When electrons are being converted into x-rays, how much is converted into x-ray energy and heat?
* 1% x-rays
* 99% heat
78
Do longer wavelengths carry more or less penetrating power?
less penetrating power
79
What is the purpose of a step-down transformer?
to decrease the voltage from the incoming 110-220 line voltage to the necessary 3-5 V used by the filament circuit
80
What is the term for the energy used to make x-rays?
electricity
81
From the following, which is the only radiation to be created in the x-ray tube?
1. alpha particles
2. beta particles
3. cathode rays
4. protons
5. neutrons
cathode rays *(the rest originate in the nucleus of an atom)*
82
List some of the uses/benefits of dental images.
* to detect lesions, diseases, and conditions of the teeth and surrounding structures that cannot be seen clinically
* to confirm or classify suspected diseases
* to localize lesions or foreign objects
* to provide information during dental procedures
* to evaluate growth and development
* to illustrate the changes of caries, disease, and trauma
* to document the condition of a patient at a specific point in time
* to aid in the development of a clinical treatment plan
83
What is the difference between the wire coils of a step-up transformer and a step-down transformer?
the wire coils in a step-up transformer have more coils in the secondary/output coil than in the primary/input coil
84
Define the term: characteristic radiation
a form of radiation that occurs when a high-speed electron dislodges an inner-shell electron from an atom, causing ionization of th atom
85
Define the term: image receptor
a recording medium *(ex: film, phosphor plates, digital sensors)*
86
What are the two ways that molecules can be formed?
1. by the transfer of electrons
2. by the sharing of electrons between the outermost shells of an atom
87
How are electrons maintained in their orbit inside the atom?
by electrostatic force (the attraction between the positive nucleus and the negative electrons)
88
What three events can occur after the x-ray beam exits the tubehead and arrives at the patient?
1. the x-rays can pass through the patient with no interaction
2. the x-rays can be completely absorbed by the patient
3. the x-rays can be scattered
89
Define the term: Compton electron / recoil electron
* an outer-shell electron that is ejected from its orbit during Compton scatter
* carries a negative charge
90
List the two groups of ionizing radiation.
1. particulate radiation
2. electromagnetic radiation
91
List the four possibilities of x-ray photon interaction with matter.
1. no interaction
2. absorption/photoelectric effect
3. Compton scatter
4. coherent scatter
92
What type of x-radiation interaction occurs most in scatter radiation?
Compton effect
93
Is the anode in the x-ray tube positively or negatively charged?
positively charged
94
What is placed over the opening of the metal housing in the x-ray tubehead to restrict the size of the exiting x-ray beam?
the lead collimator
95
List the two components of the cathode in the x-ray tube.
1. tungsten filament
2. molybdenum cup
96
Describe the effect of x-rays on living tissues.
X-rays can cause biologic changes in living cells
97
Define the term: radiation
a form of energy carried by waves or a stream of particles
98
Which has more penetrating power- primary or secondary radiation?
primary radiation
99
Describe the path of travel of x-rays.
X-rays travel in straight lines, but can be deflected/scattered
100
During the production of x-rays, what is considered a self-rectifier to alter the current of electricity?
the x-ray tube
101
Cosmic rays, gamma rays, x-rays, ultraviolet rays, visible light, infrared light, radar waves, microwaves, and radio waves are all examples of what time of ionizing radiation?
electromagnetic radiation
102
List the two types of radiation created by the conversion of the electron's kinetic energy into x-ray photons.
1. general radiation / braking radiation / bremsstrahlung radiation
2. characteristic radiation
103
What are the two measurements used to determine the binding energy?
1. electron volts **(eV)**
2. kilo electron volts **(keV) **
104
What is the purpose of the anode in the x-ray tube?
to convert the bombarding electrons from the cathode into x-ray photons that will exit the x-ray tubehead
105
What is found on the control panel of the x-ray machine?
* on-off switch and its indicator light
* exposure button and its indicator light
* control devices *(exposure time, kilovoltage, milliamperage settings)*
106
Fill in the blank: A radiograph is a ______-dimensional representation of three-dimensional object
A radiograph is a **two** -dimensional representation of a three-dimensional object
107
What is the term for the electrical current when the electrons flow in two, opposite directions?
alternating current **(AC)**
108
What part of the dental x-ray machine produces the x-rays?
the x-ray tubehead
109
When and where does thermionic emission occur in the production of x-rays?
when the electrons pass through and heat the tungsten filament in the cathode
110
What is the term for the measurement of the number of electrons moving through a conductor?
amperage **(A)**
111
What is the term for the measurement of force that causes electrons to move from the negative cathode to the positive anode in the x-ray tube?
voltage *volts = V*
112
What is the fundamental unit of matter?
the atom
113
Define the term: radiograph
an image or picture produced on an image receptor (ex: digital sensor, phosphor plate) by exposure to ionizing radiation
114
Define the term: x-radiation
a high-energy radiation produced by the collision of a beam of electrons with a metal target in an x-ray tube
115
Which component of the cathode in the x-ray tube focuses the electrons into a narrow beam to direct them toward the anode?
the molybdenum cup
116
Describe the focusing capability of x-rays.
X-rays cannot be focused to a point and will always diverge from a point
117
Define the term: ionizing radiation
radiation that is capable of producing ions by removing or adding an electron to an atom
118
What suspends the x-ray tubehead from the control panel?
the extension arm
119
How is current measured in the production of x-rays?
milliamperage **(mA)**
120
Define the term: Compton scatter
* one of the interactions of x-radiation with matter in which the x-ray photon collides with a loosely-bound, outershell electron and gives up part of its energy to eject the electron from its orbit
* the x-ray photon loses energy and continues in a different direction at a lower energy level
121
Describe the charge of x-rays.
X-rays have no charge
122
What percentage of interactions of the dental x-ray beam with matter account for the photoelectrical effect?
30%
123
Who is a dental radiographer?
any person who positions, exposes, and processes dental x-ray image receptors
124
Which circuit in the x-ray tube is controlled by the kilovoltage settings?
the high-voltage circuit
125
What device is used to increase or decrease the voltage in an electrical current?
a transformer
126
Define the term: electromagnetic radiation
the propagation of wavelike energy *(without mass)* through space or matter
127
Define the term: cathode rays
streams of high-speed electrons that originate in an x-ray tube
128
Is general or characteristic radiation more common in the conversion of electrons to x-ray photons?
general radiation
129
What type of ionizing radiation are x-rays?
electromagnetic radiation
130
Define the term: absorption
the total transfer of energy from the x-ray photon to the atoms of matter through which the x-ray beam passes
131
What electrical charge do protons carry?
positive charge
132
What prevents overheating in the metal housing of the tubehead by absorbing the heat that is created during x-ray production?
insulating oil
133
What does x-radiation absorption depend on?
* the energy of the x-ray beam
* the composition of the absorbing matter
134
What is radiology the study of?
the science or study of radiation as used in medicine
135
In dentistry, is radiation or radioactivity used?
radiation
136
Define the term: matter
anything that occupies space and has mass
137
Define the term: radioactivity
138
Why is it important that the x-ray tube rectifies the electrical current to a direct current during the production of x-rays?
direct current creates a smooth, steady supply power that will produce similar x-rays that will reduce the patient's exposure to radiation
139
Define the term: electrical current
the flow of electrons through a conductor to create electricity
140
Define the term: binding energy / binding force
the attraction between the positive nucleus and the negative electrons that maintains electrons in their orbits
141
What is the purpose of the cathode in the x-ray tube?
to produce and supply the electrons necessary to generate x-rays
142
Define the term: dental radiography
the production of radiographs of the teeth and surrounding structures by the exposure of an image receptor to x-rays
143
List the two electron classifications in particulate radiation.
1. beta particles
2. cathode rays
144
Define the term: primary radiation / primary beam / useful beam
the penetrating x-ray beam that is produced at the target of the anode and that exits the tubehead
145
What electrical charge do electrons carry?
negative
146
What component of the x-ray tube prevents generated x-rays from escaping in all directions?
the leaded-glass housing
