Chapter 4 Flashcards
Which of these statements is false?
A) Structures should be magnified to enhance interpretation.
B) An area of interest must be recorded completely with sufficient surrounding structures for a frame of reference.
C) A radiograph should be of proper density, contrast, and definition.
D) An image should be free of errors.
A) Structures should be magnified to enhance interpretation.
Each of the following is a term used to describe visual image characteristics except one. Which one is the exception?
A) Sharpness
B) Contrast
C) Milliamperage
D) Density
C) Milliamperage
Which of these statements regarding radiographic contrast is false?
A) There are few shades of gray in a radiograph with short-scale contrast.
B) Short-scale contrast describes a radiograph in which the density differences between adjacent areas are large.
C) There are many shades of gray in a radiograph with long-scale contrast.
D) Long-scale contrast describes a radiograph in which the density differences between adjacent areas are large.
D) Long-scale contrast describes a radiograph in which the density differences between adjacent areas are large.
The degree of overall blackness of a radiographic image is termed
A) Sharpness.
B) Density.
C) Resolution.
D) Contrast.
B) Density.
The difference in densities between adjacent areas on the radiograph is termed
A) Sharpness.
B) Density.
C) Resolution.
D) Contrast.
D) Contrast.
Which of these is not a shadow-casting principle?
A) A large focal spot
B) Long target—image receptor distance
C) Short object—image receptor distance
D) Parallel object—image receptor relationship
A) A large focal spot
Which of the following statements about dental radiographic exposure variables is true?
A) Increasing the mA darkens the radiograph.
B) Decreasing exposure time darkens the radiograph.
C) Exposure time is difficult to change on most x-ray machines.
D) Milliamperage affects radiographic contrast.
A) Increasing the mA darkens the radiograph.
An original radiograph is exposed at 8 mA for 1.0 second. If the mA is increased to 10, which of the following exposure times would be correct to maintain radiographic density?
A) 0.4 second
B) 0.6 second
C) 0.8 second
D) 1.0 second
C) 0.8 second
Which of these statements is false?
A) Increasing the target-image receptor distance reduces penumbra.
B) Radiation intensity is directly proportional to the square of the distance from the source.
C) A long PID increases image sharpness.
D) A recessed tube increases the target-image receptor distance.
B) Radiation intensity is directly proportional to the square of the distance from the source.
Which of the following is recommended for increasing radiographic contrast while maintaining radiographic density?
A) Increase kVp and increase exposure time.
B) Decrease kVp and decrease exposure time.
C) Increase kVp and decrease exposure time.
D) Decrease kVp and increase exposure time.
D) Decrease kVp and increase exposure time.
Which of these statements is false?
A) Structures should be magnified to enhance interpretation.
B) An area of interest must be recorded completely with sufficient surrounding structures for a frame of reference.
C) A radiograph should be of proper density, contrast, and definition.
D) An image should be free of errors.
A) Structures should be magnified to enhance interpretation.
Each of the following is a term used to describe visual image characteristics except one. Which one is the exception?
A) Sharpness
B) Contrast
C) Milliamperage
D) Density
C) Milliamperage
Radiolucent images appear dark or black because:
A) Hard radiation was not allowed to reach the image receptor.
B) Dense structures stopped x-rays from reaching the image receptor.
C) Soft radiation was stopped before reaching the image receptor.
D) Less dense structures permitted more x-rays to reach the image receptor.
D) Less dense structures permitted more x-rays to reach the image receptor.
Each of the following appears radiopaque except one, which is the exception?
A) Bone
B) Dentin
C) Pulp
D) Enamel
C) Pulp
Which kVp setting produces long-scale image contrast?
A) 65 kVp
B) 75 kVp
C) 85 kVp
D) 95 kVp
D) 95 kVp
Which of the following results in reduced image sharpness except one?
A) Patient movement during exposure
B) Image receptor positioned close to the teeth
C) A short PID
D) The use of intensifying screens
B) Image receptor positioned close to the teeth
A radiographic film emulsion with a small crystal size:
A) Creates sharpness.
B) Causes magnification.
C) Decreases exposure time.
D) Increases contrast.
A) Creates sharpness.
Image magnification can be decreased by:
A) Increasing the target-object distance.
B) Increasing the object-image receptor distance.
C) Decreasing the target-surface distance.
D) Increasing the focal spot size.
A) Increasing the target-object distance.
When changing the PID length from 8 inches (20.5 cm) to 16 inches (41 cm), what change should be made to maintain image density?
A) Decrease exposure time.
B) Increase exposure time.
C) Decrease kilovoltage.
D) Increase kilovoltage.
B) Increase exposure time.
The inverse square law states that the intensity of radiation:
A) Increases as the distance from its source increases, because the beam of radiation converges.
B) Decreases as the distance from its source increases, because the beam of radiation diverges.
C) Increases as the distance from its source increases, because the beam of radiation diverges.
D) Decreases as the distance from its source increases, because the beam of radiation converges.
B) Decreases as the distance from its source increases, because the beam of radiation diverges.
Which of the following refers to a radiographic image with many shades of gray?
A) Low contrast
B) High contrast
C) Low density
D) High density
A) Low contrast
Which of the following indicates a radiographic image with few shades of gray?
A) Short resolution
B) Long resolution
C) Short scale
D) Long scale
C) Short scale
White areas on a radiographic image are termed “radiolucent.”
False
Radiographic density (film darkening) is decreased when the milliamperage or exposure time is increased.
False
The term “short-scale contrast” describes a radiograph in which density differences between adjacent areas are small.
False
Increasing the kV results in a more penetrating x-ray beam.
True
Sharpness/definition refers to the detail and clarity of the structures on a radiograph.
True
Grids absorb scattered x-rays.
True
A small focal spot reduces penumbra.
True
Theoretically, the ideal focal spot would be a point source.
True
The target-image receptor distance should be short to create radiographs with the best definition.
False
The film should be in close physical contact with the intensifying screens.
True
A radiographic image with many shades of gray is said to have low contrast.
True
That portion of the radiographic image that appears light is called “radiolucent.”
False
Penumbra is a device used in extraoral radiography to prevent scatter radiation from fogging the image receptor.
False
It is a collimator
Some clinicians prefer a radiographic image that is of low contrast, and others prefer a radiographic image that is of high contrast.
True
Radiographic image unsharpness is generally caused by movement of the patient, image receptor, or tube head during exposure.
True
Digital imaging sharpness can be affected by pixel size and distribution.
True
Thicker intensifying screens increase the sharpness of extraoral radiographs.
False
The target-object distance is the distance between the focal spot on the target and the skin surface of the patient.
False
Only one film should be placed in contact with the intensifying screens used for extraoral radiography.
True
Slight movement of the tube head during exposure of a radiograph effectively increases the size of the focal spot on the target within the tube head.
True
The focal spot in an X-ray tube is the area on the anode surface where electrons hit and cause X-rays to be emitted
