Radiation Biology & X-ray Tubehead Key Terms Only Flashcards

Use this deck to study the terms for radiation and the creation of x-rays in the x-ray tubehead

1
Q

absorption

A
  • the total transfer of energy from the x-ray photon to the atoms of matter through which the x-ray beam passes
  • depends on the energy of the x-ray beam and the composition of the absorbing matter or tissues
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2
Q

alpha particles

A
  • a type of particulate radiation emitted from the nuclei of heavy metals
  • contain two protons and two neutrons and are positively charged
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3
Q

aluminum disks

A
  • disks or sheets of aluminum, usually 0.5mm thick, that are placed in path of the x-ray beam
  • used to filter our the nonpenetrating, longer-wavelength x-rays
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4
Q

amperage

A

the number of electrons that pass through a conductor

the strength of an electrical current

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5
Q

ampere (A)

A

the unit of measure used to describe the number of electrons passing through a conductor * (electrical current strength)*

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6
Q

anode

A
  • the positive electrode in the x-ray tube
  • consists of a wafer-thin tungsten plate embedded in a solid copper rod
  • converts electrons into x-ray photons
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7
Q

atom

A
  • a tiny, invisible particle that is the fundamental unit of matter
  • the smallest part of an element that has the properties of that element
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8
Q

neutral atom

A

an atom that contains an equal number of protons and electrons

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9
Q

atomic number

A

the total number of protons in the nucleus, which is also equal to the number of electrons outside the nucleus

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10
Q

atomic weight / mass number

A

the total number of protons and neutrons in the nucleus of an atom

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11
Q

autotransformer

A

a voltage compensator that corrects for minor fluctuations in the current flowing through the x-ray machine

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12
Q

beta particles

A

fast-moving electrons emitted from the nucleus of radioactive atoms

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13
Q

binding energy / electrostatic force / binding force

A
  • the attraction between the positive nucleus and the negative electrons that maintains electrons in their orbits
  • determined by the distance between the nucleus and electrons
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14
Q

cathode

A
  • the negative electrode in the x-ray tube
  • consists of a tungsten wire filament in a molybdenum cup
  • supplies the electrons necessary to generate x-rays
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15
Q

cathode ray

A

a stream of high-speed electrons that originate from the cathode in an x-ray tube

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16
Q

cell

A

the basic structural unit of living organisms

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17
Q

cell differentiation

A

individual characteristics of a cell that determine the response of the cell to radiation exposure

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18
Q

cell metabolism

A

the physical and chemical processes of a cell that determine the response of the cell to radiation exposure

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19
Q

central ray (CR)

A

the central portion of the primary beam of x-radiation

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20
Q

cephalostat

A

in extraoral imaging, a device that includes a receptor holder and head positioner that allow the dental radiographer to position both receptor and patient easily

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21
Q

circuit

A

a path of electrical current

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22
Q

filament circuit / low-voltage circuit

A
  • the circuit that regulates the flow of electrical current to the filament of the x-ray tube
  • controlled by the milliamperage settings
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23
Q

high-voltage circuit

A
  • the circuit that provides the high voltage required to accelerate electrons and to generate x-rays in the x-ray tube
  • controlled by the kilovoltage settings
  • uses 65,000-100,000 volts
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24
Q

coherent scatter / unmodified scatter

A
  • one of the interactions of x-radiation with matter in which the path of a low-energy x-ray photon interacts with an outer-shell electron
  • no change in the atom occurs, and an x-ray photon of scattered radiation is produced
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25
Q

collimation

A

the restriction of the size and shape of the x-ray beam in order to reduce patient exposure

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26
Q

collimator / collimating device

A

a diaphragm, usually made of lead, used to restrict the size and shape of the x-ray beam

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27
Q

Compton electron

A
  • an outer-shell electron that is ejected from its orbit during Compton scatter
  • carries a negative charge
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28
Q

Compton scatter

A

one of the interactions of x-radiation with matter in which the x-ray photon collides with a loosely bound, outer-shell electron and gives up part of its energy to eject the electron from its orbit, causing the x-ray photon to lose its energy and continue in a different direction a lower energy level

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29
Q

control devices

A
  • the components of the control panel of the x-ray machine that regulate the x-ray beam
  • includes the timer, kilovoltage and milliamperage selectors
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30
Q

control panel

A

a part of the x-ray machine that contains an on/off switch and indicator light, an exposure button and indicator light, and control devices to regulate the x-ray beam

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31
Q

copper stem

A

a portion of the anode that dissipates heat away from the tungsten target

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32
Q

coulomb (C)

A

a unit of electrical charge

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33
Q

critical organ

A

an organ that, if damaged, diminishes the quality of an individual’s life

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34
Q

cumulative effects

A

the additive effects of repeated radiation exposure

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35
Q

cumulative occupational dose

A

the accumulated lifetime radiation dose for occupationally exposed workers

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36
Q

alternating current (AC)

A

a current in which electrons flow in opposite directions

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37
Q

direct current (DC)

A

a current in which electrons flow in one direction

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38
Q

digital image

A

an image composed of pixels

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39
Q

digital imaging

A

a system of filmless imaging used to capture an image using a sensor, breaking it into electronic pieces, and presenting and storing the image using a computer

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40
Q

dose

A

the amount of energy absorbed by a tissue

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41
Q

total dose

A

the quantity of radiation received, or the total amount of radiation energy absorbed

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42
Q

dose equivilent

A

a measurement used to compare the biologic effects of different types of radiation

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43
Q

dose rate

A

the rate at which exposure to radiation occurs and the absorption takes place (determined by dose/time)

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44
Q

dose-response curve

A

a curve that can be used to correlate the damage of tissues with the amount of radiation received

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45
Q

electrical current

A

the flow of electrons through a conductor to produce x-rays

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46
Q

electricity

A
  • the energy used to make x-rays
  • used as a source of power
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47
Q

electromagnetic spectrum

A
  • the entire range of wavelengths of electromagnetic radiations
  • extends from gamma rays (with the shortest wavelengths) to radio waves (with the longest wavelengths)
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48
Q

electron

A

a tiny, negatively charged particle found outside the nucleus in the atom

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49
Q

electron volt

A

the unit of measurement for the binding energy of orbital electrons

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50
Q

element

A

substances that make up only one type of an atom

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51
Q

energy

A

what occurs when matter is altered

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52
Q

exposure

A

a measure of ionization produced in air by x-radiation or gamma radiation

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53
Q

occupational exposure

A

contact with blood or other infectious materials involving the skin, eye, or mucous membranes that results from procedures performed by the dental professional

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54
Q

exposure button

A

a component of the dental x-ray machine control panel the activates the x-ray machine to produce x-rays

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55
Q

exposure factors

A

factors that influence the density of an image (ex: milliamperage, kilovoltage, exposure time)

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56
Q

exposure incident

A

a specific incident involving contact with blood or other potentially infectious materials that results from procedures performed by the dental professional

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57
Q

exposure light

A

a component of the dental x-ray machine control panel that provides a visible signal when x-rays are produced

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58
Q

exposure time

A

the interval during which x-rays are produced

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59
Q

extension arm

A

a part of the dental x-ray machine that suspends the x-ray tubehead and houses the electrical wires that extend from the control panel to the tubehead

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60
Q

extraoral imaging

A

an inspection of large areas of the skull or jaws that requires the use of extraoral imaging receptors

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61
Q

filament circuit

A
  • regulates the flow of the electrical current to the filament of the x-ray tube using 3-5 volts
  • controlled by the milliamperage settings
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62
Q

filtration

A

the use of absorbing materials (ex: aluminum) for removing low energy x-rays from the primary beam

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63
Q

added filtration

A

aluminum disks inserted in the dental x-ray machine between the x-ray tubehead seal and collimator to remove low-energy x-rays from the primary beam

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64
Q

inherent filtration

A

portions of the x-ray tubehead that serve to filter low-energy x-rays, including the glass window of the x-ray tube, the insulating oil, and the tubehead seal

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65
Q

total filtration

A

the combination of the inherent filtration and added filtration in an x-ray machine

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66
Q

focal spot

A

the tungsten target of the anode that converts bombarding electrons into x-ray photons, concentrating the electrons and creating an enormous amount of heat

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67
Q

focal spot size

A

the size of the tungsten target of the anode

68
Q

free radical

A

an uncharged, neutral atom or molecule that exists with a single, unpaired electron in its outermost shell

69
Q

frequency

A
  • the number of wavelengths that pass a given point in a certain amount of time
  • indicates the energy of a radiation
70
Q

genetic cells

A

cells that contain genes

reproductive cells (ex: ova, sperm)

71
Q

genetic effects

A

effects of radiation that are not seen in the person irradiated but are passed on the future generations through genetic cells

72
Q

gray (Gy)

A

a unit for measuring absorbed dose

73
Q

half-value layer (HVL)

A

the thickness of material that, when placed in the path of the x-ray beam, reduces the exposure rate by one-half

74
Q

dental image

A

a two-dimensional representation of a three-dimensional object produced by the passage of x-rays through teeth and supporting structures

75
Q

extraoral image

A
  • an image that results when an image receptor is placed outside the mouth and is exposed to x-rays
  • used to examine large areas of the skull or jaws
76
Q

dental imaging

A

the creation of digital representation of anatomic structures for the purpose of diagnosis

77
Q

impulse

A

in dental imaging, a measure of exposure time

78
Q

indicator light

A

a component of the dental x-ray machine control panel that, when illuminated, indicates that the dental x-ray machine is turned on

79
Q

indirect theory of radiation

A

a theory suggesting that cell damage results indirectly, where x-ray photons are absorbed with the cell, causing the formation of toxins, which in turn, damage the cell

80
Q

insulating oil

A

oil that surrounds the x-ray tube and transformers inside the x-ray tubehead

81
Q

intensity

A

the total energy of the x-ray beam

the product of the quantity (number of x-ray photons) and quality (energy of each photon) per unit of area per time of exposure

82
Q

inverse square law

A

a rule that states that “the intensity of radiation is inversely proportional to the square of the distance from the source of radiation”

as distance is increased, the radiation intensity at the object is decreased, and vice versa

83
Q

ion

A

an electrically unbalanced particle

an atom that gains or loses an electron

84
Q

ion pair

A

one positive and one negative ion, that results when an electron is removed an atom in the ionization process, causing the atom to become the positive ion and the ejected electron becomes the negative ion

85
Q

ionization

A

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 ion

86
Q

ionizing radiation

A

radiation that is capable of producing ions by removing or adding an electron to an atom

87
Q

kiloelectron volt (keV)

A

the unit of measurement for the binding energies of orbital electrons

88
Q

kilovolt (kV)

A

the unit of measurement for voltage

89
Q

kilovoltage

A

in dental imaging, the x-ray tube peak voltage used during an exposure

90
Q

kinetic energy

A

the energy of motion

91
Q

latent period

A

the amount of time that elapses between exposure to ionizing radiation and the appearance of observable clinical signs

92
Q

lead apron

A

a flexible lead shield used to protect the patient’s reproductive and blood-forming tissues from scatter radiation

93
Q

lead collimator

A

a lead diaphragm used to restrict the size and shape of the x-ray beam

94
Q

leaded-glass housing

A

a portion of the glass housing of the x-ray tube that includes lead that prevents x-rays from escaping in all directions

95
Q

long-term effects of radiation

A

effects of radiation that appear years, decades, or generations after exposure

associated with small amounts of radiation absorbed repeatedly over a long period of time

96
Q

matter

A

anything that occupies space and has mass

97
Q

maximum permissible dose (MPD)

A

maximum dose equivalent that a body is permitted to receive in a specific period

the dose of radiation that the body can endure with little to no injury

98
Q

metal housing

A

the metal casing of the dental x-ray tubehead that houses the x-ray tube and transformers

99
Q

milliamperage

A

in dental imaging, the quantity (number) of x-ray emitted from the tubehead

100
Q

millampere (mA)

A

a unit of measurement used to describe the intensity of an electrical current

101
Q

mitotic activity

A

process of cell division

determines the response of a cell to radiation exposure (cells that divide frequently are more sensitive to radiation)

102
Q

molecule

A

two or more atoms joined together by chemical bonds

the smallest amount of a substance that possesses its characteristic properties

103
Q

molybdenum cup

A

a portion of the cathode in the x-ray tube that focuses the electrons into a narrow beam and directs that beam across the tube toward the tungsten target in the anode

104
Q

nanometer

A

a measurement used for wavelength

105
Q

neutron

A

an electrically neutral or uncharged particle

106
Q

nonstochastic effects of radiation

A

effects of radiation that have a threshold and increase in severity with increasing absorbed dose

107
Q

nucleon

A

part of an atomic nucleus (ex: protons, neutrons)

108
Q

nucleus

A

the central, positively charged core of an atom, composed of protons and neutrons

109
Q

orbit / shell

A

the well-defined path of an electron around the nucleus of an atom

110
Q

period of injury

A

occurs after the latent period following exposure to radiation and can include a variety of cellular injuries

111
Q

photoelectric effect

A

one of the interactions of x-radiation with matter where the x-ray photon collides with a tightly bound, inner-shell electron and gives up all its energy to eject that electron from its orbit; all of the energy of the photon is absorbed by the displaced electron in the form of kinetic energy

112
Q

photon

A

a bundle of energy with no mass or weight that travels as a wave at the speed of light and moves through space in a straight line

113
Q

polychromatic x-ray beam

A

an x-ray beam containing many different wavelengths of varying intensities

114
Q

position-indicating device (PID) / cone

A

an open-ended, lead-lined cylinder extending from the opening of the tubehead

aims and shapes the x-ray beam

115
Q

protective barrier

A

a barrier of radiation-absorbing material used to protect the operator from primary and scatter radiation (ex: a wall)

116
Q

proton

A

a positively-charged particle with a mass of one

117
Q

quality of the x-ray beam

A

the mean energy or penetrating ability of the x-ray beam

controlled by the kilovoltage

118
Q

quality factor (QF)

A

a factor used for radiation protection purposes that account for the exposure effects of different types of radiation

119
Q

quantity of the x-ray beam

A

the number of x-rays produced in the dental x-ray unit

controlled by the milliamperage

120
Q

radiation

A

a form of energy carried by waves or streams of particles

121
Q

background radiation

A

a form of ionizing radiation that is ubiquitous in the environment (ex: cosmic and terrestrial radiation)

122
Q

characteristic radiation

A

a form of radiation that occurs when a high-speed electron dislodges from an inner-shell electron from an atom, causing ionization of the atom

123
Q

electromagnetic radiation

A

the propagation of wavelike energy through space or matter, accompanied by electric and magnetic fields (ex: cosmic rays, gamma rays, x-rays, ultraviolet rays, visible light, infrared light, radar waves, microwaves, and radio waves)

124
Q

general radiation / bremsstrahlung radiation / braking radiation

A

a form of radiation that occurs when speeding electrons slow down because of their interaction with the tungsten target in the anode

125
Q

leakage radiation

A

any radiation, with the exception of the primary beam, that is emitted from the dental x-ray tubehead

126
Q

particulate radiation

A

tiny particles of matter that possess mass and travel in straight lines and at high speeds (ex: electrons, beta particles, alpha particles, protons, and neutrons)

127
Q

primary radiation / primary beam / useful beam

A

the penetrating x-ray beam produced at the target of the anode and exits the tubehead

128
Q

scatter radiation

A

a form of secondary radiation that results from an x-ray beam that has been deflected from its path by the interaction with matter

129
Q

secondary radiation

A

radiation created when the primary beam interacts with matter

less penetrating than primary radiation

130
Q

radiation absorbed dose (rad)

A

a unit for measuring absorbed dose

131
Q

radiation biology

A

the study of the effects of ionizing radiation on living tissues

132
Q

radioactivity

A

the process by which certain unstable atoms or elements undergo spontaneous disintegration, or decay, in an effort to attain a more balanced nuclear state

133
Q

radiograph

A

an image or picture produced on a receptor by exposure to ionizing radiation

134
Q

dental radiograph

A

a photographic image produced on a receptor by the passage of x-rays through teeth and related structures

135
Q

dental radiographer

A

any person who positions, exposes, and processes dental x-ray image receptors

136
Q

radiography

A

the art and science of making radiographs by the exposure of receptors to x-rays

137
Q

dental radiography

A

the production of radiographs of teeth and adjacent structures by the exposure of an image receptor to x-rays

138
Q

radiology

A

the science or study of radiation as used in medicine

a branch of medical science that deals with the use of x-rays, radioactive substances, and other forms of radiant energy in the diagnosis and treatment of disease

139
Q

radiosensitive cell

A

a cell that is sensitive to radiation (ex: small lymphocytes, blood, immature reproductive, young bone, and epithelial cells)

140
Q

radioresistant cell

A

a cell that is resistant to radiation (ex: bone, muscle, and nerve cells)

141
Q

recovery period

A

the period during which cellular damage caused by radiation is followed by repair

142
Q

rectification

A

the conversion of alternating current to direct current

143
Q

rotation center

A

in panoramic imaging, the axis or pivotal point on which the image receptor and the x-ray tubehead rotate around the patient

144
Q

short-term effects of radiation

A

effects of radiation that appear within minutes, days, or weeks, due to large amounts of radiation absorbed in a short time

145
Q

somatic cells

A

all cells in the body, with the exception of reproductive cells

146
Q

somatic effects

A

radiation injuries that produce changes in somatic cells and produce poor health in the irradiated individual (ex: the induction of cancer, leukemia, or cataracts)

147
Q

stepwedge

A

a device constructed of uniform-layered thickness of an x-ray absorbing material (usually aluminum) used to demonstrate densities and contrast scales

148
Q

stochastic effects of radiation

A

biologic effects from radiation that occur as a direct function of dose

the probability of occurrence increases with increasing absorbed dose; however, the severity of effects does not depend on the magnitude of the absorbed dose

149
Q

thermionic emission

A

the release of electrons from the tungsten filament when the electrical current passes through it and heats the filament

150
Q

transformer

A

a device used to increase or decrease the voltage of incoming electricity

151
Q

step-down transformer

A

in dental imaging, a device used to decrease the incoming voltage from 110 or 220 volts to the low voltage required (usually 3-5 volts)

152
Q

step-up transformer

A

in dental imaging, a device used to increase the incoming line voltage from 110 or 220 volts to the high voltage required (usually 65,000-100,000 volts)

153
Q

tubehead

A

the tightly sealed heavy metal housing that contains the dental x-ray tube, including the metal housing, insulating oil, tubehead seal, x-ray tube, transformers, aluminum disks, lead collimator, and position-indicating device

contains a filament used to produce electrons and a target used to produce x-rays

154
Q

tubehead seal

A

the aluminum or leaded-glass covering of the tubehead that seals the oil in the tubehead and filters the x-ray beam

155
Q

tungsten filament

A

a coiled wire of tungsten in the cathode in the x-ray tube that produces electrons when heated

156
Q

tungsten target

A

a portion of the anode in the x-ray tube that serves as a focal spot and converts bombarding electrons into x-ray photons

157
Q

vacuum tube

A

a sealed glass tube from which most of the air has been evacuated

158
Q

velocity

A

in dental imaging, the speed of a wave

159
Q

volt (V)

A

the unit of measurement for voltage

160
Q

voltage

A

in dental imaging, the measurement of force that refers to the potential difference between two electrical charges

161
Q

wavelength

A

the distance between the crest of one wave and the crest of the next wave

determines the energy and penetrating power of the radiation

162
Q

x-radiation

A

a high-energy radiation produced by the collision of a beam of electrons with a metal target in the x-ray tube

163
Q

x-rays

A

a beam of energy that has the power to penetrate substances and record image shadows on image receptors

164
Q

x-ray beam angulation

A

one of the influencing factors for image distortion that refers to the direction of the x-ray beam

165
Q

x-ray tube

A

a component part of the x-ray tubehead that generates x-rays, including the leaded-glass vacuum tube, cathode, and anode