Written Exam 2 Flashcards
This person discovered X-rays
Used cathode rays on photo plate in his physics lab
Roentgen
This individual performed the first intraoral x-ray in 1895
Walkoff
This individual is known as the father of U.S. dental radiography
Kelly
Who developed “hot cathode” coolidge tube (hot, inefficient) using tungsten
Shockproof unit in 1919
Coolidge
This individual warned of X-ray damage and developed patient protection guidelines
Rollins
What warned of X-ray damage and developed patient protection guidelines
Rollins
What is the study or science of radiation as used in medicine/dentistry
Radiology/Roentgenology
What is a recorded images produced by X-ray on photographic film
radiograph
What is a transparent material covered with photographic emulsion
film
What serves the same purpose as film, receive the radiation?
What are the different types?
sensor
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Direct digital detectors = wired to the computer, receives the remnant radiation
- Most sensitive - meaning less radiation is necessary
- Indirect digital detector = are used like film, photostimulable phosphor (PSP) imaging plates are thin and w/o wires, take in the remnant radiation and a computer reads it and produces a latent image
What is the act of making or exposing a radiograph?
exposure
***Radiographs are MADE, not taken
What appears dark on the radiograph, signifies a lack of structure or a less dense structure which higher amounts of remnant radiation passed through to sensor during exposure
Radiolucent
X-rays go through the image and have slight refraction
pulp chambers and sinuses
Appears light on a radiograph, signifies the presence of increasingly dense structure where little remnant radiation from exposure can reach the sensor
Radiopaque
X-rays cannot penetrate the structure
Enamel, restorations
What is the lamina dura?
Space around the tooth root
Explain the process of producing an X-ray
- Produced by bombarding a tungsten target (anode) with a stream of high-velocity electrons
- The electrons are produced at the tungsten filament (cathode) and are propelled toward the anode
- Onto a focal spot
Explain the component of an X-ray Tube
-
Cathode (-)
- Filament is a coil of tungsten
- Electrons released by thermionic emission - “boiling off” of electrons
- Focusing cup of negative molybdenum directs the cathode electrons to the Anode
-
Anode (+)
- Tungsten in a copper stem
- Target of the Cathode electrons
-
Focal Spot
- Where in the Tungsten target of the Anode the electrons are directed, smaller means a sharper image
What are the types of radiation produced upon electrons hitting the target?
- Bremsstrahlung Radiation (Breaking Radiation) - high energy electrons are deflected by forces within the atom
- Characteristic Radiation - the high energy electrons strike and eject electrons from their valence shells
- Give off energy as photons
What are the types of controlling factors in X-rays?
-
kV - kilovoltage
- Controls speed of electrons from cathode to anode (- to +)
- Controls quality of the X-ray beam
- High vK means more penetrating power
-
mA - milliamperage
- controls the number of electrons produced, thus controlling quantity of X-rays
- High mA means a dark radiograph
-
s- Time
- Also has an impact on quantity of X-rays
- Ex: 1 impulse = 1/60 sec
Which of the following controls the number of electrons produced, thus controlling quantity of X-rays
mA - milliamperage
What controls speed of electrons from cathode to anode (- to +) and controls the quality of the X-ray beam.
kV - kilovoltage
High vK means more penetrating power
What is the degree of blackness of the radiograph?
How is it effected?
What are the controlling factors?
Radiographic Density
Effected by X-ray quantity - how many X-rays are produced
Controlling factors: milliamperage (mA) and time (s)
What is the number of shades of gray on the radiograph?
How is it effected?
What is the controlling factor?
Radiographic Contrast
Effected by X-ray quality - how well the beam can penetrate
Controlling Factor: Kilovoltage (kV)
What the difference between high contrast and low contrast?
- High contrast = short scale, less shades of gray
- Low contrast = long scale, lots of shades of gray
High vK means increased energy/penetration and lower contrast
Think of contrast as an amount of “difference”
- High contrast, high difference - less gray area, each color contrasts more with the next
- Low contrast, low difference - more gray, each color is less contrasting with the next
From a grain hopper and belt standpoint, describe the difference between the Density vs. contrast
- Quantity of grains (electrons) controlled by mAs
- Speed (energy/quality) of the grains (electrons) controlled by kV
Explain the process of making an X-ray
- X-radiation (production of X-ray as described previously) is emitted from the end of the cone
- X-rays pass through patient tissues
- Relatively Dense tissues arrest some of the X-rays
- Some X-rays pass through tissue and hit the film/sensor
- X-rays that hit the film/sensor produce varying shades of gray (beam quality, penetration, kV) depending on the amount of radiation exposure
- Produce the black, white, gray representation of the various densities of each tissue - relative to tissue densities ad the X-ray
What does a full mouth radiographic survey consist of?
Explain each type of x-ray
14 periapical and 4 bitewings
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Bitewings - see both upper and lower arches, apex of the root and alveolar bone not well represented
- Diagnostic, used to detect caries
- Must be able to visualize the interproximal spaces to see incipient decay
- Overlap of proximal surfaces would mean the bitewing is non-diagnostic
- Periapical - show only an upper and lower, visualize the crown, root and 2-3 mm of surrounding bone
Explain the types of pulpal abnormalities and what they are caused by
- Pulp stones - age or parafunctional activities
- Obliterated pulp - hard tissue deposits fills the pulp, leave it narrow and restricted
What are bitewing carious lesions?
Serve diagnostic purpose of bitewing
- Demineralization
- Consider the carious lesion’s proximity to the DEJ
What is at the apex of the tooth, lesion as a result of pulp death?
Periapical