DA Radiography Week 3
Dental Assisting Radiography Week 3 Study Guide. - Dental Radiography Principles & Techniques Fourth Ed.
Dental Assisting Radiography Week 3 Study Guide. - Dental Radiography Principles & Techniques Fourth Ed.
RADIOLUCENT
- the portion of a processed radiograph that is dark or black. *A structure that appears radiolucent lacks density & permits the passage of the x-ray beam with little or no resistance
RADIOPAQUE
- the portion that appears light or white. Radiopaque structures are dense and absorb or resist passage of the x-ray beam -ex. dentin, enamel and bone.
DIAGNOSTIC RADIOGRAPH
- proper density and contrast
*The ideal radiograph is not too light and not too dark
DENSITY
- the overall blackness or darkness of a radiograph
* Millamperage (MA), kilovoltage peak (kVp) and exposure time can all affect the density of a radiographMILLIAMPERAGE & KILOVOLTAGE PEAK
- Milliamperage (mA) is the quantity of x-rays emitted from the tubehead. If mA is increased, density increases making film darker - Kilovoltage peak (kVp) is the maximum or peak voltage that is used during an x-ray exposure. The quality of the x-ray depends on the kVp. If kVp is increased, so is density
EXPOSURE TIME
- exposure time defines the density of a film. *The longer the exposure time, the darker the radiograph. *The shorter the exposure time the lighter the radiograph.
SUBJECT THICKNESS
- the thickness of soft tissue and bone in a patient.
CONTRAST
- Contrast refers to the density of radiograph
-High contrast- very dark and very white areas on a radiograph
-Low contrast-not very dark or light areas, but many shades of gray
FILM CONTRAST
-Film contrast-refers to the characteristics of the receptor (film) that influence radiographic contrast.
* The qualities of the film are under the control of the manufacturer and cannot be changed.
* Film processing is under the control of the dental radiographer.
SUBJECT CONTRAST
- the characteristics of the subject that influence radiographic contrast. *Subject contrast is determined by thickness, density and composition & can be altered by increasing or decreasing the kVp
SCALES OF CONTRAST
- Scale of contrast refers to the range of useful densities seen on a dental radiograph. - Short scale contrast is a radiograph that shows only areas of black and white. A lower kilovoltage results in a short scale contrast. - Long scale contrast is a radiograph that exhibits many shades of gray. A higher kilovoltage results in a long scale contrast.
STEPWEDGE
- a stepwedge can be used to demonstrate short and long scale contrast. *A stepwedge consists of uniform-layered thickness of an x-ray absorbing material.
SHARPNESS
- (also known as detail, resolution, definition) refers to how well the smallest detail of an object is reproduced on a radiograph
* The sharpness of an image is influenced by 3 factors: focal spot size, film composition, & movement.
PENUMBRA
- the un-sharpness or blurring of the edges on a radiograph
FOCAL AREA
- The smaller the focal area, the sharper the image - The larger the focal area, the less-sharp the image
SILVER HALIDE CRYSTALS - SHARPNESS
- Sharpness is relative to the size of crystals found in the film emulsion. *Larger crystals produce less sharpness *smaller crystals produce more image sharpness
TARGET RECEPTOR DISTANCE
- the distance between the source of x-rays and the image receptor which is determined by the length of the PID.
*A longer PID results in less image magnification
OBJECT-RECEPTOR DISTANCE
- the distance between the object being radiographed (the tooth) and the image receptor.
*The tooth and the film should be placed as close as possible to each other. -The closer the tooth is to the film, the less it is magnified.
DISTORTION
- Distortion of a radiographic image is a variation in the true size and shape of the object being radiographed. *Distortion results from improper film alignment or beam angulation *To minimize distortion, the object & the film must be parallel to each other. <A distorted image may appear too short or too long. (foreshortened or elongated)> * The central ray of the x-ray beam must be perpendicular(at a right angle or intersecting) to the tooth and the film
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Flashcards
RADIOLUCENT
- the portion of a processed radiograph that is dark or black. *A structure that appears radiolucent lacks density & permits the passage of the x-ray beam with little or no resistance
RADIOPAQUE
- the portion that appears light or white. Radiopaque structures are dense and absorb or resist passage of the x-ray beam -ex. dentin, enamel and bone.
DIAGNOSTIC RADIOGRAPH
- proper density and contrast
*The ideal radiograph is not too light and not too dark
DENSITY
- the overall blackness or darkness of a radiograph
* Millamperage (MA), kilovoltage peak (kVp) and exposure time can all affect the density of a radiographMILLIAMPERAGE & KILOVOLTAGE PEAK
- Milliamperage (mA) is the quantity of x-rays emitted from the tubehead. If mA is increased, density increases making film darker - Kilovoltage peak (kVp) is the maximum or peak voltage that is used during an x-ray exposure. The quality of the x-ray depends on the kVp. If kVp is increased, so is density
EXPOSURE TIME
- exposure time defines the density of a film. *The longer the exposure time, the darker the radiograph. *The shorter the exposure time the lighter the radiograph.
SUBJECT THICKNESS
- the thickness of soft tissue and bone in a patient.
CONTRAST
- Contrast refers to the density of radiograph
-High contrast- very dark and very white areas on a radiograph
-Low contrast-not very dark or light areas, but many shades of gray
FILM CONTRAST
-Film contrast-refers to the characteristics of the receptor (film) that influence radiographic contrast.
* The qualities of the film are under the control of the manufacturer and cannot be changed.
* Film processing is under the control of the dental radiographer.
SUBJECT CONTRAST
- the characteristics of the subject that influence radiographic contrast. *Subject contrast is determined by thickness, density and composition & can be altered by increasing or decreasing the kVp
SCALES OF CONTRAST
- Scale of contrast refers to the range of useful densities seen on a dental radiograph. - Short scale contrast is a radiograph that shows only areas of black and white. A lower kilovoltage results in a short scale contrast. - Long scale contrast is a radiograph that exhibits many shades of gray. A higher kilovoltage results in a long scale contrast.
STEPWEDGE
- a stepwedge can be used to demonstrate short and long scale contrast. *A stepwedge consists of uniform-layered thickness of an x-ray absorbing material.
SHARPNESS
- (also known as detail, resolution, definition) refers to how well the smallest detail of an object is reproduced on a radiograph
* The sharpness of an image is influenced by 3 factors: focal spot size, film composition, & movement.
PENUMBRA
- the un-sharpness or blurring of the edges on a radiograph
FOCAL AREA
- The smaller the focal area, the sharper the image - The larger the focal area, the less-sharp the image
SILVER HALIDE CRYSTALS - SHARPNESS
- Sharpness is relative to the size of crystals found in the film emulsion. *Larger crystals produce less sharpness *smaller crystals produce more image sharpness
TARGET RECEPTOR DISTANCE
- the distance between the source of x-rays and the image receptor which is determined by the length of the PID.
*A longer PID results in less image magnification
OBJECT-RECEPTOR DISTANCE
- the distance between the object being radiographed (the tooth) and the image receptor.
*The tooth and the film should be placed as close as possible to each other. -The closer the tooth is to the film, the less it is magnified.
DISTORTION
- Distortion of a radiographic image is a variation in the true size and shape of the object being radiographed. *Distortion results from improper film alignment or beam angulation *To minimize distortion, the object & the film must be parallel to each other. <A distorted image may appear too short or too long. (foreshortened or elongated)> * The central ray of the x-ray beam must be perpendicular(at a right angle or intersecting) to the tooth and the film
