Cathode Ray
a beam of electrons emitted by the cathode of an electrical discharge tube
Fluorescence
light emitted during absorption of radiation of some other (invisible) wavelength
Radiation
a form of energy carried by waves or a stream of particles.
Radiograph, dental
a photographic image produced on film by the prassage of x-ray through teeth and related structures.
Radiographer, dental
Any person who positions, exposes, and processes dental x-ray film.
Radiography
the art or science of making radiographs by the exposure of film to x-rays.
Radiography, dental
the production of radiographs of the teeth and adjacent structures by the exposure of film to x-rays.
Radiology
the science or study of radiation as used in medicine.
Vacuum Tube
sealed class tube from which most of the air has been evacuated.
X-radiation
a high-energy radiation produced by the collision of a beam of electrons with a metal target in an x-ray tube.
X-ray(s)
a beam of energy that has the power to penetrate substances and record image shadows on photographic film.
Radiograph
a picture on film produced by the passage of x-rays through an object or body; also called x-ray film. x-ray
Absorption
refers to the total transfer of energy from the x-ray photon to the atoms of matter through which the x-ray beam passes.
Alpha particles
a type of particulate radiation emmited from the nuclei of heavy metals; contain two protons and teo neutrons and are positively charges.
Aluminum disks
disks or sheets of aliminum, that are placed in the path of the x-ray beam; filter out the nonpenetrating, longer wavelength x-rays.
Amperage
the number of electrons that pass through a conductor, the strength of an electrical currrent
Ampere (A)
a unit of electrical current stregnth. the intensity of an electric current produced by 1 volt acting through resistance of 1 ohm.
Anode
positive pole of x-ray tube. the positive electrode in the x-ray tube. consists of a waffer-thin tungsten plate embedded in a solid copper rod; converts electrons into x-ray photons.
Atom
a tiny, invisable particle that is the fundamental unit of matter; the smallest part of an element that has properties of that element.
Atom, neutral
an atom that contains an equal number of protons (positive) and electrons (negative).
Atomic number
each atom has an atomic number that corresponds to the total number of protons in the nucleus.
Atomic weight
The total number of protons and nuetrons in the nucleus of an atom. (mass number)
Autotransformer
a voltage compensator that corrects for minor fluctuations in the current flowing through the x-ray machine.
Beta Particles
fast moving electrons emitted from the nucleus of radioactive atoms.
Binding energy
the attraction between the positive nucleus and the negative electrons that maintains electrons in thier orbits; determined by the distance between the nucleus and the electrons. K is the strongest O is the weakest. (electrosatic force/binding force)
Bremmstrahlung
general raditaition/breaking radiation, the term breaking refers to the sudden stopping of high-speed electrons when they hit the tungsten target in the anode. most x-rays are produced in this manner, approx 70% of the x-ray energy produced can be classif
Cathode
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.
Circuit, filament
the circuit that regulated the flow of the electrical current to the filament of the x-ray tube; controlled by the miliampere setting(low voltage circuit).
Circuit, high-voltage
the current that provides the high voltage required to accelerate electrons and to generate x-rays in the x-ray tube; controlled by the kilovoltage settings.
Coherent scatter
one of the interactions of the x-radiation with matter in which the path of an x-ray photon is altered by matter without a change in energy. (unmodified scatter)
Compton electron
an outer-shell electron that is ejected from its orbit during Compton scatter; this electron carries a negative charge.
Compton scatter
one of the interactions of x-radiation with matter in which the xray photon is deflected from its path and loses energy.
Control panel
part of the dental x-ray machine that regulate the x-ray beam; includes the timer, kilovotage, and milliamperage selectors.
Copper stem
a portion of the anode that disspitaes heat away from the tungsten target.
Current, alternating (AC)
a current in which electrons flow in oppisite directions.
Current, direct (DC)
a current in which electrons flow in one directions.
Electrical current
the flow of electrons through a conductor, an electrical current used to produce x-rays.
Electricity
an electrical current used as a source of power; the energy used to make x-rays.
Electromagnetic spectrum
energies of eletromagnetic radiation arranged in diagrammatic form on a chart.
Electron
a tiny negatively charged particle found in the atom.
Electron volt (eV)
the unit of measurement for the binding energies of orbital electrons.
Electrostatic force
the attraction between the positive nucleus and the negative electrons that maintain electrons in their orbit;determined by the distance between the nucleus and electrons. K is the stongest O is the weekest. (binding force/binding energy)
Element
a simple substance made up of atoms.
Energy
the capacitiy for doing work.
Extension arm
a part of the dental x-ray machine; suspends the x-ray tubehead and houses electrical wires that extend from the control panel to the tubehead.
Frequency
the number of complete wave lengths that pass a point in a given time; indicates the energy of the radiation.
Insulating oil
oil that surrounds the x-ray tube and transformers inside the tubehead.
Ion
an elecrtically charged particle; an atom that gains or loses an electron
Ion pair
a pair of ions, one positive and one negative, that results when an electron is removed from an atom on the ionization process.
Ionization
the production of ions; the process of converting an atom into an ion.
Kilo electron volt (keV)
1000 electron volts, the unit of measurement for the binding energies of orbital electrons.
Kilovolt (kV)
1000 volts; a unit of electromotive force that drives an electrical current through a circuit.
Kilovoltage peak (kVp)
the maximum or peak voltage that is used during x-ray exposure.
Kinetic energy
energy of motion
Lead collimator
a lead diaphragm or tubular device used to restrict the size and shape of the x-ray beam.
Lead-glassed housing
the leaded-glass housing of the x-ray tube.
Mass number
atomic weight
Matter
something that occupies space and has weight.
Metal housing
the metal body of the dental x-ray tubehead that surrounds the x-ray tube and transformers.
Milliamperage
the intensity of the x-ray tube current used during exposure, measured in mA's.
Milliampere (mA)
1/1000 of a ampere; a unit of measurement used to describe the intensity of an electrical current.
Molecule
two or more atoms joined together by chemical bonds, or the smallest amount of a substance that possesses its characteristic properties.
Molybdenum cup
a portion of the cathode in the x-ray tube; focuses the electrons into a narrow beam and directs the beam across the tube toward the tungsten target in the anode.
Nanometer
a measurement used for wavelength; one equals one-billionth of a meter
Neutron
an electrically neutral or charged particle with the mass of one.
Nucleon
part of an atomic nucleus. (protons/neutrons)
Nucleus
the central, positively charged core of an atom; composed of protons and neutrons.
Orbit
the well-defined path of an electron around the nucleus of an atom. (shell)
Periodic Table (of the elements)
a chart that arranges elements in increasing atomic number.
Photoelectric effect
one of the interactions of x-radiation with matter; an x-ray photon interacts with an orbital electron, and all the energy of the photon is absorbed by the displaced electron in the form of kenetic energy.
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. (quatna)
Position-indicating device (PID)
an open-ended, lead-lined cylinder extending from the opening of the metal housing of the tubehead; aims and shapes the x-ray beam. (cone)
Primary beam
the penetrating x-ray beam produced at the target of the anode. (primary beam/useful beam)
Proton
a positively charged particle with a mass of one.
Quanta
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. (photon)
Radiation, breaking
(bremsstrahlung/radiation general) the term breaking refers to the sudden stopping of high-speed electrons when they hit the tungsten target in the anode. most x-rays are produced in this manner. approx 70% of the x-rays energy produced can be classified
Radiation, characteristic
a form of radiation that occurs when a high-speed electron dislodges an inner-shell electron from an atom, casuing excitation or ionization of the atom.
Circuit
a path of electrical current.
Radiation, electromagnetic
the propagation of wavelike energy through space or matter; the prpoagated energy is accompanied by electric and magnetic fields, thus the term electromagnertic. (ie. cosmic waves, gamma rays, x-rays, ultraviolet rays, visible light, infrared light, radar
Radiation, general
bremsstrahlung/breaking raditaion, the term breaking refers to the sudden stopping of high speed electrons when they hit the tungsten target in the anode. most x-rays are produced in this manner. approx 70% of the x-rays energy produced can be
Radiation, ionizing
radiation capable of producing ions; includes particulate or electromagnetic raditaion.
Radiation, particulate
tiny particles of matter that posses mass, travel in straight lines, and travel at high speeds. (ie electrons, beta particles, alpha particles, proton, and neutrons.)
Radiation, primary
the penetrating x-ray beam produced at the target of the anode. (ie primary/useful beam)
Radiation, scatter
a form of seconary radiation; results from an x-ray beam that has been deflected from its path by the interaction with matter.
Radiation, secondary
radiation created when the primary beam interacts with matter. Secondary radiation is less penetrating than primary radiation.
Radioactivity
the process by which certain unstable atoms or elements undergo spontaneous disintegration in an effort to attain a more balanced nuclear state.
Recoil electron
Compton electron. An outter shell electron that is ejected from its orbit during compton scatter; this electron carries a negative charge.
Rectification
the conversion of alternating current to direct current.
Scatter
refers to the type of radiation that it is possible for an x-ray photon to be deflected from its path during its passage through matter.
Shell
Orbit. the well defined path of an electron around the nucleus of an atom.
Thermionic emission
the release of electrons that occur when the tungsten filament of the cathode is heated to incandescence; the outer-shell electons of the tungstenatom acquire enough to move away from the filament surface and form an electron cloud.
Transformer
a device used to increase or decrease tje voltage of incoming electricity.
Transformer, step-down
a device used to decrease the voltage from the incoming 110-220 DOWN TO THE 3-5 volts used by the filament circuit. has MORE coils in the primary than the secondary coil. (primary is recieving coil/ the secondary coil in the output coil).
Transformer, step-up
a device used to increase the voltage from the voltage from the in coming 110-220 line voltage to the 65,000 to 10,000 volts used by the high-voltage circuit. A high-voltage circuit uses both a step-up and an autotransformer.
Tubehead
the tightly sealed heavy metal housing that contains the dental x-ray tube; includes the metal housing, insulating oil, tubehead seal, x-ray tube, transformers, alumnium disk, lead collimator, and PID(position indicating device).
Tubehead seal
the aluminum or lead-glass covering of the tubehead that permits the exit of x-rays from the tubehead; seald the oil in the tubehead and filters the x-ray beam.
Tungsten Filament
a portion of the cathode in the x-ray tube. a coiled wire of tungsten that produces electrons when heated.
Tungsten target
a portion of the anode in the x-ray tube. serves as a focal point and converts bombarding electrons into x-ray photons.
Unmodified scatter
Coherent scatter. one of the interactions of x-radiation with matter in which the path of an x-ray photon is altered by metter without a change in energy.
Useful beam
the [enetrating x-ray beam produced at the target of the anode (primary beam/radiation).
Velocity
speed. in dental radiography the speed of a wave.
Volt (V)
the unit of electromotive force that drives an electrical current through a circuit.
Voltage
in dental radiography, electrical pressure or force that drives the electrical current through the circuit of the x-ray machine.
Wavelength
the distance between the crest of one wave to the crest of the next; determines the energy and penetrating power of the radiation. (shorter wavelength the higher the energy.)
X-ray tube
a component part of the x-ray tubehead that generates the x-rays. (includes leaded-glass vacuum tube, cathode, and anode.)
Contrast
the differencce in degrees of blackness between adjacent areas on a radiograph.
Density
the overall darkness or blackness of a radiograph
Exposure time
the time interval during which x-rays are produced.
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.
Impulse
a measure of exposure time; 60 impulses occur in 1 second.
Intensity (of an x-ray beam)
the total energy of the x-ray beam. the product of the quantity (# of x-ray photons) and the quality(energy of each photon) per unit of area per time of exposure.
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, radiation intensity at the object is decreased, and vise versa.
Kilovoltage
the x-ray tube peak voltage that is used during an x-ray exposure.
Milliampere-seconds (mAs)
a unit of radiographic exposure equal to the product of milliamperage and exposure time.
Polycromatic x-ray beam
an x-ray beam containing many different wavelengths of varying intensities.
Quality (of x-ray beam)
the mean energy or penetrating ability of the x-ray beam; the quality of the x-ray beam is controlled by kilovoltage.
Quantity (of x-ray beam)
the number of x-rays produced from the tubehead; the quantity of x-rays produced is controlled by millamperage.