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201 Cards in this Set
- Front
- Back
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A form of energy carried by waves of a stream of particals
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Radiation
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A high energy radiation produced by the collision of a beam of electrons witn a metal target in a x-ray tube
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X-Radiation
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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 othe forms of radiant energy in the diagnosis and treatment of disease
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Radiology
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A beam of energy that has the power to penetrate substances and record image shadows on photographic films
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X-Ray
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A picture of film produced by then passage of x-rays through an object or body
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Radiograph
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A photigraphic image produced on film by the passage of x-rays through teeth and related structures
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Detntal Radiograph
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The art and science of making radiographs by the exposure of film to x-rays
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Radiography
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the making of radiographs of the teeth and adjecent structures by the exposure of film to x-rays
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Dental radiography
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What are the uses of dental radiographs
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To detect lesions, diseases and condition
to confirm or classify disease To localize foreign objects To provide info, during bdental procedures To evaluate changes secondary to carries, periodontal disease, and trauma to document the condition of a patient at a specific point in time |
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What are the professional goals of a radiographer
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Patient protection
Operator protection Patient education Operator competance operator efficiency production of quality radiographs |
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The atom consits of what two parts?
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Nucleus
Electros |
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The nucleus consists of?
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Protons
Neutrons |
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What are positively charged particles?
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Protons
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What are negatively charged particles?
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Neutrons
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The number of protons and neutrons in the nucleus determine the?
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Atomic weight
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The number of protons determines the? And it equals to the number of?
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Atomic number
Electrons |
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Negatively charged particles that travel around the nucleus in well-defined paths also called?
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Electrons
Orbits or shells |
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How many shells can an atom have?
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7
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How are electrons maintained in their orbits?
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Electrostatic force
Binding energy |
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Two or more atoms bound together by chemical bond.
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Molecule
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When the number of protons and the number of electrons are equal the atom/molecule is said to be?
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State of equilibrium
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What is a neutral atom?
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Protons equal electrons
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An atom that gains or loses an electron and becomes electrically unbalanced.
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Ion
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What is Ionization?
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The process of converting an atom into an ion.
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Process by which certain unstable atoms of elements undergo spontaneous decay in an effort to attain a more balanced nuclear state.
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Radioactivity
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Radiation that is capable of producing ions by removing or adding an electron to an atom.
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Ionizing Radiation
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What are the two types of Ionizing radiation?
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Particulate
Electromagnetic |
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Tiny particles of matter that possess mass and travel in straight lines and at high speeds; transmit kinetic energy by means of their extremely fast-moving, small masses.
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Particulate radiation
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Propagation of wavelike energy (without mass) through space or matter; accompanied by oscillating electric and magnetic fields.
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Electromagnetic radiation
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What are some examples of particulate radiation?
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Electrons
Beta particles Alpha particles Protons Neutrons |
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What are some examples of Electromagnetic radiation?
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Radiotherapy
Dental radiography Sun Photography Microwave Radar Television Radio |
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Most Electromagnetic radiations are nonionizing; _____________ and __________ are ionizing radiations.
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X-rays
Gamma rays |
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What are the properties of Electromagnetic radiation?
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Has no mass or weight
Has no electrical charge Travels at the speed of light Travels as both a particle and wave Propagates an electric field Propagates a magnetic field Has diff. measurable energies (frequencies & wavelengths) |
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What is the particle concept?
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Characterizes Electromagnetic radiation as bundles of energy called photons or quanta.
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What is the wave concept?
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Characterizes Electromagnetic radiation as waves and focuses on velocity, wavelength and frequency.
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Term used to describe speed of a wave? What is the speed of an Electromagnetic wave?
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Velocity
186,000 miles/second |
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What is the distance between waves called? The shorter the distance the _____ the energy.
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Wavelength
greater |
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What determines the energy and the penetrating power of the radiation?
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The wavelength
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How is a wavelength measured?
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Nanometers or meters
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Long wavelength is ___ frequency and short wavelength is ____ frequency.
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Long - Low
Short - High |
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Refers to the number of wavelengths that pass a given point in a given amount of time.
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Frequency
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How is frequency measured?
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In Hertz
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_____ and ____ are inversely related.
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Frequency and Wavelength
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Weightless bundles of energy (photons) without electrical charge that travel in waves with a specific frequency at the speed of light.
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X-rays
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What is the appearance of x-rays?
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Invisible and cannot be detected by any of the senses.
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What is the mass of x-rays?
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X-rays have no mass or weight
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What is the charge of x-rays?
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No electrical charge
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What is the speed of an x-ray?
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Speed of light
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What is the wavelength of an x-ray?
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X-rays travel in wavelengths and have short wavelengths with a high frequency.
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What is the path of travel of an x-ray?
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X-rays travel in a straight of line and can be deflected or scattered.
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What is the focusing capability of an x-ray?
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X-rays cannot be focused to a point and always diverge from a point.
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What is the penetrating power of an x-ray?
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X-rays can penetrate liquids, solids, and gases.
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What are the absorption properties of x-rays?
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X-rays are absorbed by matter; the absorption depends on the atomic structure of matter and the wavelength of the x-ray.
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What are the ionizing capabilities of x-rays?
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X-rays interact with materials they penetrate and cause ionization.
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What are the fluorescence capabilities of x-rays?
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X-rays can cause certain substances to fluoresce (visible light, ultraviolet light)
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What effect do x-rays have on film?
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X-rays can produce an image on photographic film.
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What effect do x-rays have on living tissue?
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X-rays can cause biologic changes in living cells (ionization).
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What are the components of an x-ray machine?
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Control panel
Extension arm Tube head aka PID |
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What are the compents of the x-ray tube?
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Leaded-gladd housing
Cathode Anode |
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What is the cathode?
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Negative electrode, consists of tungsten filament and molybdenum cup.
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A coiled wire found in the cathode which produces electrons when heated.
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Tungsten filament
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Focuses electrons into a narrow beam and directs the beam across the tube toward the anode.
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Molybdenum cup
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What is an anode?
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Positive electrode, consists of a tungsten target and copper stem; converts electrons into x-ray photons.
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A plate which serves as a focal spot and converts bombarding electrons into x-ray photons>
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Tungsten target
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Functions to dissipate the heat away from the tungsten target.
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Copper stem
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Energy that is used to produce x-rays; consists of a flow of electrons through a conductor.
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Electricity
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Measurement of the number of electrons moving through a conductor.
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Amperage
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Current is measured in?
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Ameres (A) or milliamperes (mA)
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Measurement of electrical force that causes electrons to move from a negative pole to a positive one.
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Voltage
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Voltage is measured in?
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vots (V) or kilovolts (kV)
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Path of electrical current.
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Circuit
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Low voltage circuit, uses 3 to 5 volts, and is controlled by mA.
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Filament circuit
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This type of circuit, uses 65,000 to 100,000 volts, and is controlled by kV.
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High-voltage circuit
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Device used to either increase or decrease the voltage in an electrical circuit.
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Transformer
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What decreases voltage?
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Step-down transformer
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What increases voltage?
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Step-up transformer
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Serves as a voltage compensator that corrects for minor flunctuations in the current.
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Autotransformer
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Release of electrons from the tungsten filament when the electrical current passes through and heats up the filament.
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Thermionic emission
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Which direction do the electrons travel in the x-ray tube?
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From the cathode to the anode.
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When the electron strike the tungsten target and their kinetic energy (energy in motion) is converted to?
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X-ray energy 1%
Heat 99% |
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What are the types of x-rays produced?
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General or braking aka (bremsstrahlung)
Characteristic radiation |
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When the electrons come to a stop when they hit the tungsten target and go off to another direction. What percentage of this type of radiation takes place?
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General or braking (bremsstrahlung) 70%
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Type of x-ray produced when one electron hits another inner electron and dislodges it from the atom causing ionization. % of time that this happens?
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Characteristic radiation
30% |
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Type of radiation that exits the tubehead and patient is exposed to it.
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Primary radiation
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Type of radiation that is created after radiation hits matter and bounces off in another direction; exposes operator.
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Secondary radiation
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Type of radiation that hits matter and goes all over the place.
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Scatter radiation
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What are the interactions of x-radiation?
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x-rays can pass through patient w/o interaction
x-rays can be completely absorbed by the patient x-rays can be scattered |
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Which type of interaction of x-rays makes dental radiography possible?
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No interaction
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When an x-ray photon collides with a tightly bound inner shell electron and gives up all it's energy by ejecting the electrons. The photon ceases to exist.
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Photoelectric effect - where ionization occurs. 30%
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When an x-ray photon collides with a loosely bound outer-shell electron and gives up part of its energy to eject the electron. The photon loses energy and continues in a different direction.
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Compton Scatter - 62%
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When a low energy x-ray photon interacts with an outer-shell electron, no change occurs, no energy is lost and scatter radiation is produced; no ionization occurs. Change in direction without change in energy.
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Coherent Scatter - 8%
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The scatter in coherent scatter is termed?
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Coherent scatter or unmodified scatter
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Used to describe the mean energy or penetrating ability of the x-ray beam.
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Quality
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What is quality controlled by?
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Kilovoltage (kV)
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Determines the speed of electrons that travel from cathode to anode.
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Voltage
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Voltage is controlled by?
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Vots or Kilovolts
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Unit of measure used to describe the potential that drives an electrical current through a circuit.
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Volt
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How many kV does dental radiography require?
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65 - 100 kV
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A highter kV should be used when the area to be examined is?
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Thick or dense
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Kilovoltage is controlled by?
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Kilovoltage peak (kVp)
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Maximum voltage
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Kilovoltage peak
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What type of x-ray beam does a peak voltage result in?
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Polychromatic x-ray beam
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Beam that contains many different wavelengths of varying intensities.
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Polychromatic x-ray beam
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Overall darkness or blackness of film.
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Density
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Refers to how sharply dark and light areas are differentiated or separated on a film.
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Contrast
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Refers to the interval of time during which x-rays are produced.
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Exposure time - 1/60 sec.
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Refers the number of x-rays produced.
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Quantity
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Quantity is controlled by?
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Milliamperage
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How is exposure time measured?
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Impulses
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Unit of measure used to describe the number of electrons, or current flowing through the cathode filament.
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Ampere
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What regulates the temperature of teh cathode filament.
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Milliamperage
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Distance from the source of radiation tot he patient's skin is called?
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Target-surface distance
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Distance from the source of radiation to the tooth is called?
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Target-object distance
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Distance from the source of radiation to the film is called?
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Target-film distance
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The intensity of radiation is inversely proportional to the square of the distance from the source of radiation.
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Inverse Square Law
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If you double the target-film distance, the exposure time must be ______.
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Quadrupled.
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If you raise the milliamperage what happens to the number of x-rays?
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It goes up.
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The product of the quantity and quality per unit of time of exposure.
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Intensity
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Intensity is affected by?
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kVp, mA, exposure time, and distance
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The thickness of a material such as aluminum, that when placed in the path of the x-ray beam reduces the intensity by half.
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Half-value layer. (HVL)
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An instrument that is used to help the dental radiographer position the PID in relation to the tooth and film is the?
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Beam alignment device
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A device used to stabilize an intraoral film is a?
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Film holder
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A metal instrument that is used to restrict the size of teh x-ray beam to the size of an intraoral film is the?
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Collimating device
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What visual characteristics directly influence the diagnostic quality of a dental radiograph?
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Density
Contrast |
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What is density influenced by?
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mA
kVp Time Subject thickness |
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An increase in mA produces more or less x-rays? increases or decreases density? Will the radiograph appear lighter or darker?
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More x-rays
Increase in density Darker radiograph |
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If kVp is increased, what happens to the density and the color of radiograph?
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Increased density
Darker radiograph |
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An increase in exposure time will result in ____ density and the radiograph will be ______
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Increased density
Darker radiograph |
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Difference in the degrees of blackness between adjacent areas.
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Contrast
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Contrast is influenced by?
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kVp
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Refers to the characteristics of the film that influence radiographic contrast.
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Film contrast
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Refers to the characteristics of the subject that influences radiographic contrast.
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Subject contrast
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What influences subject contrast?
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Thickness
Density Composition of subject |
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If you increase kVp what happens to the contrast?
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Low contrast
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High contrast is also referred to as?
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Short-scale contrast
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Low contrast is also referred to as?
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Long-scale contrast
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A device used to demonstrate short-scale and long-scale contrast.
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Stepwedge
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What can be used to monitor the quality of the film and film processing.
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Stepwedge
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What can be used to demonstrate film densities?
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Stepwedge
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Capability of the x-ray film to reproduce the distinct outline of an object.
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Sharpness
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The fuzzy, unclear area that surrounds a radiograph image is termed?
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Penumbra
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The sharpness of a film is influenced by?
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Focal spot size
Film composition Movement |
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Another term for tungsten target is?
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Focal Spot
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The smaller the focal spot area the more or less sharp the image appears.
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More sharp
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Smaller crystals produce more or less image sharpness
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More sharp
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Larger crystals produce more or less image sharpness
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Less sharp
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Enlargement of the image, results from the divergent paths of teh x-ray beam.
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Magnification
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What is magnification influenced by?
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Target-film distance
Object-film distance |
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A longer PID (16 inches) and target-film distance results in more or less image magnification?
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Less image magnification
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What happens to film magnification when the proximity of the tooth to film is closer?
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Less magnification
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Object-film distance should be ____________ in order to reduce image enlargement.
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As close as possible
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A variation in the size and shape of the object, results from the unequal magnification of different parts of teh same object.
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Distortion
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What is distortion influenced by?
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Object-film alignment
X-ray beam angulation |
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How do you get proper object-film alignment?
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Tooth and film must be parallel.
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How do you get proper x-ray beam angulation?
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The x-ray beam must be directed perpendicular to the tooth and the film.
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What are the principles of shadow casting?
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The source of radiation should be as small as possible.
The distance from source to object should be as long as possible. The distance from object to the film should be as small as possible. The object and the film should be parallel. The radiation should strike the object and film at right angles. |
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What are the 3 types of intraoral radiographic examinations?
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Periapical examination
Interproximal examination Occlusal examination |
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This type of examination is used to examine the entire tooth, crown and root.
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Periapical examination
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What type of film do you use in periapical examination?
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Periapical film
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What technique do you use in periapical examination?
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The paralleling technique
The bisecting technique |
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Type of examination that examines the crowns of both the maxillary and mandibular teeth in a single film.
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Interproximal examination
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Why type of film do you use in interproximal examinations?
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Bite-wing film
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What technique do you use in interproximal examinations?
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Bite-wing technique
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Type of examination that examines large areas of the maxilla or the mandible on one film.
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Occlusal examination
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What type of film do you use with an occlusal examination?
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Occlusal film
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What technique do you use with an occlusal examination?
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Occlusal technique
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What is the term used to describe a full-mouth series or complete series?
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CMRS (Complete Mouth Radiographic Series)
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Regions of the maxilla and mandible where 32 teeth of the human dentition are normally located.
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Tooth-bearing areas
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What types of radiographs are included in CMRS?
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Periapical and bite-wing radiographs.
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What are some examples of extraoral radiographs?
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Panoramic radiograph
Lateral jaw Lateral cephalometric Posteroanterior Waters Submentovertex reverse Towne Transcrania Tomographic projections |
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What are the two types of film mounting methods?
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Labial and Lingual
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Which method of mounting places raised or convex side of the dot facing the radiographer?
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Labial
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Which method of mounting places depressed (concave) side of the dot facing the radiographer?
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Lingual
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Which mounting method is recommended by the American Dental Association?
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Labial
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In which mounting method are the radiographs viewed as if the technician is looking directly at the patient?
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Labial
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In which mounting method is the patient's right the technician's left?
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Labial
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What information do you include on a film mount?
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Patient's full name
Date of exposure Dentist's name Radiographer's name |
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Flexible piece of polyester plastic .2 mm in thickness that is constructed to withstand heat, moisture, and chemical exposure.
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Film base
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Thin layer that covers both sides of the film base.
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Adhesive layer
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Coating attached to both sides of the film base that gives film greater sensitivity to x-radiation.
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Emulsion
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Is made up of a homogenous mixture of gelatin and silver halide crystals.
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Emulsion
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Chemical compound that is sensitive to radiation or light.
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Halide
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Thin transparent coating placed over the emulsion.
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Protective layer
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Invisible pattern of stored energy exposed on film
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Latent image
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This sheet is positioned behind the film to shield it from secondary radiation.
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Lead foil sheet
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This side of the film packet is solid white and has a raised bump in one corner.
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Tube side
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This side of the film packet has a flap used to open the film packet and remove the film for processing.
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Label side
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Explain the different sizes of Periapical film.
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Size 0 - very small children
Size 1 - Anteriors of adults Size 2 - Ant. & Post of adults aka standard film |
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Explain the different sizes of Bite-wing film.
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Size 0 - Post. of very small children
Size 1 - Post. in children and Ant. in adults (vertically Size 2 - Post. in adults (most used) Size 3 - longer and narrower shows all post. teeth on one side of arch |
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Explain the different sizes of Occlusal film.
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Four times as large as size 2
Size 4 - used to show large areas of upper or lower jaw. |
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Refers to the amount of radiation required to produce a radiograph of standard density.
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Film speed
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Film speed is determined by?
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Size of silver halide crystals
Thickness of emulsion Presence of special radiosensitvie dyes |
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The larger the crystals, the slower or faster the film speed.
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The faster
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What are two common extraoral films.
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Panoramic
Cephalometric |
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This type of extraoral film shows the bony and soft tissue areas of the facial profile.
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Cephalometric film
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A device that transfers x-ray energy into visible light.
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Intensifying screen
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Fluorescent crystals found in intensifying screens are called.
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Phosphors.
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Conventional screens that have phosphors that emit blue light.
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Calcium tungstate screens
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Screens that emit green light and are more efficient and faster.
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Rare earth screens
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Why is contact between the screen and the film critical?
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Because lack of contact will result in loss of image sharpness.
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Explain the process of duplicating film.
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Duplicating film must be processed in dark room, has emulsion on one side only and it's dull, side without emulsion is shiny. The emulsion side of the film must contact the radiograph during the duplication process.
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