Term
| The larger the crystal in the intensifying screen the _____ amount of radiation is needed? |
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Definition
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Term
| The detail of the larger crystal in the intensifying screen is? |
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Definition
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Term
| Fast screens require a smaller or larger exposure? |
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Definition
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Term
| What is the primary purpose of an intensifying screen? |
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Definition
| To achieve the same radiograph with less radiation. |
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Term
| T/F-Approximately 75% of the exposure recorded on a film is due to the light emitted from the intensifying screens? |
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Definition
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Term
| T/F-A cassette must not maintain close contact between the intensifying screens and the film. |
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Definition
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Term
| T/F-Faster screen speeds require a small exposure and produce less detail; slow screens require a larger exposure and produce greater detail. |
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Definition
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Term
| T/F-Screens must be cleaned regularly. Dirt and hair on the screen can cause radiographic artifacts. |
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Definition
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Term
| T/F-X-ray film is manufactured in only one speed and by one manufacturer. |
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Definition
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Term
| The conversion of x-radiation into visible light occurs via: |
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Definition
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Term
| To absorb backscatter, the back of most cassettes is lined with: |
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Definition
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Term
| Intensifying screens allow: |
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Definition
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Term
| The main advantage of today's rare earth coated intensifying screens is: |
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Definition
| They have a higher x-ray to light conversion efficiency |
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Term
| T/F-Non-screen film requires greater exposure. |
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Definition
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Term
| A processed film that has not been exposed to ionizing radiation or visible light will appear: |
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Definition
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Term
| What are the appropriate storage conditions for radiographic film? |
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Definition
| 10-15C, 40%-60% humidity, vertical |
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Term
| Which film screen systems is most commonly used in veterinary medicine? |
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Definition
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Term
| What type of crystals are present in an intensifying screen? |
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Definition
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Term
| What percent of the latent image on the film are a result of the intensifying screens? |
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Definition
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Term
List four advantages to using an intensifying screen?
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Definition
1) Decrease patient motion due to shorter exposure time.
2) Decrease patient exposure level
3) Decrease scatter radiation level to personnel
4) Permist use of smaller focal spot size; hence better detail
5) Increase tube life because of lower mAs required
6) Permits greater selection in kVp settings |
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Term
| List and describe the four layers of an intensifying screen. |
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Definition
1) Base or support layer-tough, moisture resistant surface, flexible support to attach to cassette
2) Reflective layer-attached to the base, made of aa white substance (titanium dioxide) that reflects light back to the x-ray film
3) Phosphorus crystal layer-phosphorus crystals suspended within a binding material
4) Protective coat-clear coating that protects the phosphorus layer; easy to clean |
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Term
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Definition
| Inconsistent fluorescence from the phosphor layer results in spotty, moth-eaten appearance. |
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Term
| What x-ray intensifying screen provides the least detail on the developed film? |
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Definition
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Term
| Calcium tungstate in the intensifying screens of an x-ray casset emits what color of light when bombarded by an x-ray beam? |
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Definition
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Term
| One disadvantage of the rare-earth screen is the resultant density variation that can occur on a uniform exposed radiographic film as a result of the fewer x-rays required. What is the name of this spotty radiographic artifact? |
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Definition
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Term
| An intensifying screen that contains large crystals of calcium tungstate produces which of the following characteristics? |
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Definition
| Fast screens, less detail, high grain |
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Term
| What consideration is most important when splitting an x-ray cassette into two separate images? |
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Definition
| Position the animal so that all views are facing the same direction. |
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Term
| Why are intensifying screens added to an x-ray cassette? |
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Definition
| To cause light exposure of the film |
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Term
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Definition
| A permanent record containing diagnostic information for immediate diagnostics and future reference. |
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Term
| List and describe the four layers of an x-ray film. |
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Definition
1) Base-provides a flexible support with a thin adhesive layer on each side that binds the emulsion to the base.
2) Emulsion-gelatin layer that contains silver halide microcrystals suspended and evenly dispersed in the gelatin.
3) Silver halide-contain members of the halogen family. Billions of crystals suspended in emulsion.
4) Supercoat-protective outer layer. |
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Term
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Definition
| The invisible image on the x-ray film after it is exposed to ionizing radiation or visible light before processing. |
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Term
| What color does a piece of film right out of the box appear (according to the board questions)? |
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Definition
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Term
| What happens to the silver halide crystals that are exposed? |
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Definition
| They split. When processed they will convert to metallic silver and turn black. |
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Term
| What happens to unexposed silver halide crystals when the film is processed? |
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Definition
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Term
| List and describe the three types of film speed. |
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Definition
1) Fast film-larger silver halide crystals, requires less exposure, grainy image lacking definition
2) Medium film-Most widely used. Compromise between a fine grain and speed.
3) Slow film-smaller silver halide crystals, requires greater exposure or light from screens, less grainy image with good definition |
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