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 (165 cards)
1
Q
collimator / collimating device
A
a diaphragm, usually made of lead, used to restrict the size and shape of the x-ray beam
2
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
3
Q
dental radiograph
A
a photographic image produced on a receptor by the passage of x-rays through teeth and related structures
4
Q
electron
A
a tiny, negatively charged particle found outside the nucleus in the atom
5
Q
vacuum tube
A
a sealed glass tube from which most of the air has been evacuated
6
Q
collimation
A
the restriction of the size and shape of the x-ray beam in order to reduce patient exposure
7
Q
radioresistant cell
A
a cell that is resistant to radiation (ex: bone, muscle, and nerve cells)
8
Q
cell differentiation
A
individual characteristics of a cell that determine the response of the cell to radiation exposure
9
Q
copper stem
A
a portion of the anode that dissipates heat away from the tungsten target
10
Q
total dose
A
the quantity of radiation received, or the total amount of radiation energy absorbed
11
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
12
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
13
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
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
15
Q
matter
A
anything that occupies space and has mass
16
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
17
Q
metal housing
A
the metal casing of the dental x-ray tubehead that houses the x-ray tube and transformers
18
Q
latent period
A
the amount of time that elapses between exposure to ionizing radiation and the appearance of observable clinical signs
19
Q
dose-response curve
A
a curve that can be used to correlate the damage of tissues with the amount of radiation received
20
Q
secondary radiation
A
radiation created when the primary beam interacts with matter
less penetrating than primary radiation
21
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
22
Q
voltage
A
in dental imaging, the measurement of force that refers to the potential difference between two electrical charges
23
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)
24
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)
25
wavelength
the distance between the crest of one wave and the crest of the next wave
determines the energy and penetrating power of the radiation
26
exposure incident
a specific incident involving contact with blood or other potentially infectious materials that results from procedures performed by the dental professional
27
recovery period
the period during which cellular damage caused by radiation is followed by repair
28
gray **(Gy)**
a unit for measuring absorbed dose
29
electrical current
the flow of electrons through a conductor to produce x-rays
30
impulse
in dental imaging, a measure of exposure time
31
cumulative effects
the additive effects of repeated radiation exposure
32
nucleon
part of an atomic nucleus (ex: protons, neutrons)
33
dose
the amount of energy absorbed by a tissue
34
maximum permissible dose (MPD)
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
35
dental image
a two-dimensional representation of a three-dimensional object produced by the passage of x-rays through teeth and supporting structures
36
dental imaging
the creation of digital representation of anatomic structures for the purpose of diagnosis
37
x-radiation
a high-energy radiation produced by the collision of a beam of electrons with a metal target in the x-ray tube
38
x-rays
a beam of energy that has the power to penetrate substances and record image shadows on image receptors
39
exposure factors
factors that influence the density of an image *(ex: milliamperage, kilovoltage, exposure time)*
40
nanometer
a measurement used for wavelength
41
thermionic emission
the release of electrons from the tungsten filament when the electrical current passes through it and heats the filament
42
central ray **(CR)**
the central portion of the primary beam of x-radiation
43
dental radiographer
any person who positions, exposes, and processes dental x-ray image receptors
44
rotation center
in panoramic imaging, the axis or pivotal point on which the image receptor and the x-ray tubehead rotate around the patient
45
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 ion
46
leakage radiation
any radiation, with the exception of the primary beam, that is emitted from the dental x-ray tubehead
47
ion pair
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
48
free radical
an uncharged, neutral atom or molecule that exists with a single, unpaired electron in its outermost shell
49
cephalostat
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
50
x-ray tube
a component part of the x-ray tubehead that generates x-rays, including the leaded-glass vacuum tube, cathode, and anode
51
milliamperage
in dental imaging, the quantity (number) of x-ray emitted from the tubehead
52
inverse square law
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
53
focal spot
the tungsten target of the anode that converts bombarding electrons into x-ray photons, concentrating the electrons and creating an enormous amount of heat
54
stepwedge
a device constructed of uniform-layered thickness of an x-ray absorbing material (usually aluminum) used to demonstrate densities and contrast scales
55
transformer
a device used to increase or decrease the voltage of incoming electricity
56
dose equivilent
a measurement used to compare the biologic effects of different types of radiation
57
step-up transformer
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)
58
general radiation / bremsstrahlung radiation / braking radiation
a form of radiation that occurs when speeding electrons slow down because of their interaction with the tungsten target in the anode
59
dose rate
the rate at which exposure to radiation occurs and the absorption takes place *(determined by dose/time)*
60
rectification
the conversion of alternating current to direct current
61
ionizing radiation
radiation that is capable of producing ions by removing or adding an electron to an atom
62
period of injury
occurs after the latent period following exposure to radiation and can include a variety of cellular injuries
63
filtration
the use of absorbing materials *(ex: aluminum)* for removing low energy x-rays from the primary beam
64
atomic weight / mass number
the total number of protons and neutrons in the nucleus of an atom
65
beta particles
fast-moving electrons emitted from the nucleus of radioactive atoms
66
tubehead seal
the aluminum or leaded-glass covering of the tubehead that seals the oil in the tubehead and filters the x-ray beam
67
lead collimator
a lead diaphragm used to restrict the size and shape of the x-ray beam
68
extraoral imaging
an inspection of large areas of the skull or jaws that requires the use of extraoral imaging receptors
69
kilovolt (kV)
the unit of measurement for voltage
70
dental radiography
the production of radiographs of teeth and adjacent structures by the exposure of an image receptor to x-rays
71
quantity of the x-ray beam
the number of x-rays produced in the dental x-ray unit
controlled by the milliamperage
72
circuit
a path of electrical current
73
total filtration
the combination of the inherent filtration and added filtration in an x-ray machine
74
aluminum disks
* 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
75
amperage
the number of electrons that pass through a conductor
the strength of an electrical current
76
molybdenum cup
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
77
electricity
* the energy used to make x-rays
* used as a source of power
78
extension arm
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
79
genetic cells
cells that contain genes
reproductive cells *(ex: ova, sperm)*
80
volt (V)
the unit of measurement for voltage
81
radiosensitive cell
a cell that is sensitive to radiation (ex: small lymphocytes, blood, immature reproductive, young bone, and epithelial cells)
82
inherent filtration
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
83
short-term effects of radiation
effects of radiation that appear within minutes, days, or weeks, due to large amounts of radiation absorbed in a short time
84
exposure
a measure of ionization produced in air by x-radiation or gamma radiation
85
lead apron
a flexible lead shield used to protect the patient's reproductive and blood-forming tissues from scatter radiation
86
kilovoltage
in dental imaging, the x-ray tube peak voltage used during an exposure
87
neutron
an electrically neutral or uncharged particle
88
direct current **(DC)**
a current in which electrons flow in one direction
89
cell metabolism
the physical and chemical processes of a cell that determine the response of the cell to radiation exposure
90
radiation
a form of energy carried by waves or streams of particles
91
coulomb **(C)**
a unit of electrical charge
92
autotransformer
a voltage compensator that corrects for minor fluctuations in the current flowing through the x-ray machine
93
tungsten filament
a coiled wire of tungsten in the cathode in the x-ray tube that produces electrons when heated
94
polychromatic x-ray beam
an x-ray beam containing many different wavelengths of varying intensities
95
radiography
the art and science of making radiographs by the exposure of receptors to x-rays
96
nonstochastic effects of radiation
effects of radiation that have a threshold and increase in severity with increasing absorbed dose
97
frequency
* the number of wavelengths that pass a given point in a certain amount of time
* indicates the energy of a radiation
98
Compton scatter
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
99
control devices
* the components of the control panel of the x-ray machine that regulate the x-ray beam
* includes the timer, kilovoltage and milliamperage selectors
100
mitotic activity
process of cell division
determines the response of a cell to radiation exposure (cells that divide frequently are more sensitive to radiation)
101
added filtration
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
102
molecule
two or more atoms joined together by chemical bonds
the smallest amount of a substance that possesses its characteristic properties
103
exposure button
a component of the dental x-ray machine control panel the activates the x-ray machine to produce x-rays
104
element
substances that make up only one type of an atom
105
somatic cells
all cells in the body, with the exception of reproductive cells
106
protective barrier
a barrier of radiation-absorbing material used to protect the operator from primary and scatter radiation (ex: a wall)
107
photoelectric effect
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
108
filament circuit / low-voltage circuit
* the circuit that regulates the flow of electrical current to the filament of the x-ray tube
* controlled by the milliamperage settings
109
nucleus
the central, positively charged core of an atom, composed of protons and neutrons
110
electron volt
the unit of measurement for the binding energy of orbital electrons
111
ion
an electrically unbalanced particle
an atom that gains or loses an electron
112
half-value layer **(HVL)**
the thickness of material that, when placed in the path of the x-ray beam, reduces the exposure rate by one-half
113
ampere **(A)**
the unit of measure used to describe the number of electrons passing through a conductor * (electrical current strength)*
114
orbit / shell
the well-defined path of an electron around the nucleus of an atom
115
alpha particles
* a type of particulate radiation emitted from the nuclei of heavy metals
* contain two protons and two neutrons and are positively charged
116
cathode ray
a stream of high-speed electrons that originate from the cathode in an x-ray tube
117
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 outer-shell electron
* no change in the atom occurs, and an x-ray photon of scattered radiation is produced
118
stochastic effects of radiation
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
119
critical organ
an organ that, if damaged, diminishes the quality of an individual's life
120
quality factor (QF)
a factor used for radiation protection purposes that account for the exposure effects of different types of radiation
121
tungsten target
a portion of the anode in the x-ray tube that serves as a focal spot and converts bombarding electrons into x-ray photons
122
characteristic radiation
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
exposure light
a component of the dental x-ray machine control panel that provides a visible signal when x-rays are produced
124
binding energy / electrostatic force / binding force
* 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
125
insulating oil
oil that surrounds the x-ray tube and transformers inside the x-ray tubehead
126
digital imaging
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
127
high-voltage circuit
* 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
128
proton
a positively-charged particle with a mass of one
129
digital image
an image composed of pixels
130
energy
what occurs when matter is altered
131
velocity
in dental imaging, the speed of a wave
132
background radiation
a form of ionizing radiation that is ubiquitous in the environment *(ex: cosmic and terrestrial radiation)*
133
kiloelectron volt (keV)
the unit of measurement for the binding energies of orbital electrons
134
position-indicating device (PID) / cone
an open-ended, lead-lined cylinder extending from the opening of the tubehead
aims and shapes the x-ray beam
135
electromagnetic spectrum
* the entire range of wavelengths of electromagnetic radiations
* extends from gamma rays (with the shortest wavelengths) to radio waves (with the longest wavelengths)
136
anode
* 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
137
photon
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
138
leaded-glass housing
a portion of the glass housing of the x-ray tube that includes lead that prevents x-rays from escaping in all directions
139
radiation biology
the study of the effects of ionizing radiation on living tissues
140
indicator light
a component of the dental x-ray machine control panel that, when illuminated, indicates that the dental x-ray machine is turned on
141
radioactivity
the process by which certain unstable atoms or elements undergo spontaneous disintegration, or decay, in an effort to attain a more balanced nuclear state
142
filament circuit
* regulates the flow of the electrical current to the filament of the x-ray tube using 3-5 volts
* controlled by the milliamperage settings
143
electromagnetic radiation
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)*
144
alternating current **(AC)**
a current in which electrons flow in opposite directions
145
focal spot size
the size of the tungsten target of the anode
146
quality of the x-ray beam
the mean energy or penetrating ability of the x-ray beam
controlled by the kilovoltage
147
radiation absorbed dose (rad)
a unit for measuring absorbed dose
148
radiograph
an image or picture produced on a receptor by exposure to ionizing radiation
149
atom
* a tiny, invisible particle that is the fundamental unit of matter
* the smallest part of an element that has the properties of that element
150
exposure time
the interval during which x-rays are produced
151
cumulative occupational dose
the accumulated lifetime radiation dose for occupationally exposed workers
152
neutral atom
an atom that contains an equal number of protons and electrons
153
somatic effects
radiation injuries that produce changes in somatic cells and produce poor health in the irradiated individual (ex: the induction of cancer, leukemia, or cataracts)
154
indirect theory of radiation
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
155
cell
the basic structural unit of living organisms
156
Compton electron
* an outer-shell electron that is ejected from its orbit during Compton scatter
* *carries a negative charge*
157
extraoral image
* 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
158
kinetic energy
the energy of motion
159
genetic effects
effects of radiation that are not seen in the person irradiated but are passed on the future generations through genetic cells
160
x-ray beam angulation
one of the influencing factors for image distortion that refers to the direction of the x-ray beam
161
occupational exposure
contact with blood or other infectious materials involving the skin, eye, or mucous membranes that results from procedures performed by the dental professional
162
atomic number
the total number of protons in the nucleus, which is also equal to the number of electrons outside the nucleus
163
primary radiation / primary beam / useful beam
the penetrating x-ray beam produced at the target of the anode and exits the tubehead
164
scatter radiation
a form of secondary radiation that results from an x-ray beam that has been deflected from its path by the interaction with matter
165
millampere (mA)
a unit of measurement used to describe the intensity of an electrical current
