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97 Cards in this Set
- Front
- Back
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At what relative speed is a fast system usually available?
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400 speed system
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At what relative speed is a slow system usually available?
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100 speed system
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Screen systems that are relatively slow, thereby reqiuring greater exposure and resulting in higher patient doses
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"Detail" or "Extremity" systems
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Detail or extremity screen systems produce excellent recorded detail. T OR F
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True
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Factors that affect how fast or slow an intensifying screen.
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-Absorption efficiency
-Conversion efficiency -Thickness of phosphor layer -Size or phosphor layer |
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Refers to the screen's ability to absorb the incident x-ray photons.
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Absorption efficiency
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Describes how well the screen phosphors takes x-ray photons and converts them to visible light.
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Conversion efficiency
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Absorbs approximately 60% of the incident photons.
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Rare earth phosphors
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Absorbs approximately 30% to 40% of incident photons.
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Calcium tungstate
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What causes rare earth phosphors to be faster than calcium tungate?
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Increased absorption and conversion efficiency
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What has an impact on screen speed for both calcium tungstate and rare earth materials?
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-Thickness of phospher layer
-Size of crystal |
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What are the final factors that affect screen speed?
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-presence or absence of reflecting layer
-light absorbing layer -light absorbing dyes in phospher layer |
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Used to increase screen speed by reflecting light back toward the film.
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Reflecting layer
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Thin film transistors (TFTs) are used in DR systems to what?
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Temporarily store the electrical charge
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The latent image that consists of electrons trapped in the phosphor layer is found with what?
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CR latent image
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Typically, as screen speed decreases,________ decreases.
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Density
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The wire mesh tool is used to evaluate what?
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Film screen contact
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The image receptor for computed radiography (CR)is composed of what?
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Barium Flourohalide
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What strategy reduces quantum mottle?
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Reducing kVp and increasing mAs
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Both types of DR flat panel detector digital imaging systems convert x-rays energy into what?
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Electrical charges
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What is the result of deposits of silver ions at the sensitivity specks in the emulsion?
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Film latent image
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What is formed by electrons trapped in the barium fluorohalide (in the phosphor layer)?
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CR latent image
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What is the electrical charge stored in the transistor?
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DR latent image
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System that has the x-ray absorbed by a layer of cesium iodide(CsI), a scintillation phosphor, which then produces a flash of light.
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Indirect conversion system
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System that has the x-ray interact directly with a layer of amorphous selenium(a-Se), which then produces the electrical charge.
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Direct conversion system
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Converts the invisible image on exposed film into permanent visible radiographic image.
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Processing
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What does automatic processing equipment consist of?
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-Tanks
-Rollers -systems -processing stages |
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Is a device that encompasses chemical tanks, a roller transport system, and a dryer system for the processing of radiographic film.
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Automatic processor
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Reduces exposed silver halide to metallic silver and to add electrons to exposed silver halide.
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Developing or reducing agents
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What is the pH of the developing stage?
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alkaline
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What is the pH of the fixing stage?
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acid
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List the 4 types of rollers in a processor
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entrance, transport, turnaround, crossover
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List in order the steps in automatic film processing
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developing, fixing, washing, drying
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This is said to be a fast reducer, producing gray densities.
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phenidone
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If film is not washed properly brownish or yellowish staining may occur due to. . .
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thiosulfate remaining on film
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What percentage of moisture should the radiograph retain after drying stage?
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10-15%
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This is a said to be a slow reducer, producing black densities.
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hydroquinone
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Replenishment is necessary because chemicals eventually become ________.
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exhausted
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_________ is the heating coil that is immersed in the developing and fixing tanks.
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Immersion heater
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Darkrooms must be free from all outside ____ ______.
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white light
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FIFO is an acronym for. . .
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first in first out
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Film should be stored at temperatures between ________ and humidity between ________.
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50 - 70 degrees and 40 - 60%
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Three types of darkroom doors
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single, revolving, maze
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Name the two types of roller positioning.
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staggered and parallel
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Conversion of the latent image to the manifest image is accomplished by:
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radiographic processing
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the sequential order for processing radiographic film is:
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developing, fixing, washing, drying
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which of the following solutions are responsible for reducing the exposed silver halide crystals to black metallic silver: 1. ammonium thiosulfate, 2. hydroquinon, or 3. phenidone?
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2 & 3 only (hydroquinon & Phenidone)
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the pH environment required for proper development of the exposed film is
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alkaline
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the fixing agent used to clear the undeveloped silver halide crystals is:
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ammonium thiosulfate
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Staining or fading of the permanent image results when too much ________ remains on the film w/ improper washing.
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Thiosulfate
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finished radiographs should retain what percentage of their moisture:
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10%-15%
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The type of roller responsible for moving the film from the bottom of the tank upward is a(n)________ roller
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turnaround
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The type of roller responsible for moving the film from one tank to another is a(n) __________ roller
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crossover
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Processing chemicals must be replenished to maintain activity and volume when depleted primarily by
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exhaustion
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Decreasing the developer temperature
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decreases density
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Under what environmental conditions should radiographic film be stored?
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temperature between 50 degrees and 70 degrees F and relative humidity between 40% and 60%.
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Safelight filters are chosen based on the
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film sensitivity
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the type of silver-recovery unit that uses an electrically charged drum to attract the silver is called a(n) ________ unit.
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electrolytic
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A comon plus-density artifact caused from bending the film is
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half-moon marks
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The more Xrays phospor layer absorbs, the ______ efficient the screen is in absorbing xray photons
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More efficient
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The more xray photons converted to visibl light the _______ efficient the scren's conversion is
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More efficient
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What does phosphor do?
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creates light
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The thinner the phosphor layer the more light emitted (T or F)
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False, the THICKER the layer
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The more light produced the faster the screen speed (T or F)
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True
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Larger phosphor crystals ____________ detail (because it produces more light, more spread)
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Decreases detail
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because the reflecting layer causes the light photons to travel frther and spread out more the recorded detail is ____________
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decreased
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Where is the foil located on cassettes and what is it used for?
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On the back, to stop back scatter from reaching back to the film
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What is the most common digital system?
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CR
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what does the photstimulatable layer contain?
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barium photo halide
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What makes your latent image in CR? Is it released light or trapped electrons?
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Trapped electrons
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A cassette is used in CR (computed radiography Imaging) True or False?
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true
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How is a latent image created in DR imaging?
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via electrical charge pattern
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What type DR conversion is converted to light then to charge?
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indirect conversion
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What type of DR conversion is converted directly to charge?
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Direct conversion
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What makes a latent image on film?
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deposits of silver ions at the sensitivity specks in the emulsion
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what makes a latent image on CR?
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electrons trapped in the barium fluorohalide crystals (in the phosphor layer)
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what makes the latent image on DR?
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electric charge stored in the transistor
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What converts latent image to manifest image?
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processing
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what is the processor capacity?
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number of fils that can be processed per hour.
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what color densities does phenidone produce?
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gray densities
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what color densities does hydrouinone produce?
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black densities
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What pH is developer?
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alkaline
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what is solvent
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when processing chemicals are mixed up w/ water
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What chemical is used in the fixor for processing?
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ammonium thiosulfate
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what does an acidic pH do?
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stops development of image
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what will happen if you do not remove ammonium thiosulfate?
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you will have brownish yellow staining and fading.
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How much water needs to be removed from film during drying process?
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85-90%
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The higher the develoer temperature the _________ the radiographic density
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greater
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Silver recovery must be done off-site (true or false)
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False, can be done on or off-site
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Exposes the film to water that contains less thiosulfate than the film does
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Diffusion
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Clears away unexposed silver halide
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Fixing agent
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Dilutes the chemicals
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Solvent
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Clears undeveloped silver halide from film
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Silver halide
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Amount of time it takes to process a single piece of film
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Processing cycle
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Responsible for reducing the exposed silver halide crystals to metallic silbver, visualized as radiographic densities.
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Developing agents
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Needs an alkaline pH environment for the chemicals to fuction properly
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Developer solution
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Absorbs radiation and converts the energy into electrical signals.
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flat panel direct capture detector(in permanent location)
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