Chapter 8 Flashcards
Which of the following is an exception about digital radiography?
A) The radiographer “acquires an image” in digital imaging.
B) A digital image has no physical form.
C) Digital radiography systems are limited to intraoral systems.
D) Indirect digital imaging replaces film with a photostimulable plate.
C) Digital radiography systems are limited to intraoral systems.
What is the term for the allowable amount of radiation exposure to produce a diagnostic image?
A) Noise
B) Gray value
C) Digital subtraction
D) Dynamic range
D) Dynamic range
Which statement about pixels is false?
A) The digital image is composed of structurally ordered pixels.
B) Each pixel is a single dot in a digital image.
C) “Pixel” is short for “pixel element.”
D) Each pixel has a number from 1 to 10.
D) Each pixel has a number from 1 to 10.
Which statement about pixels is an exception?
A) The more pixels, the higher the resolution and sharper the image.
B) The number and size of pixels determine the spatial resolution of an image.
C) When pixels are few, the image appears jagged.
D) A pixel with a stored number of 0 would be pure white.
D) A pixel with a stored number of 0 would be pure white.
How many shades of gray can the human eye detect?
A) 32
B) 320
C) 3,200
D) 32,000
A) 32
Which is not a use of digital radiography?
A) To evaluate growth and development
B) To image soft tissues of the head and neck region
C) To detect, confirm, and classify oral diseases
D) To detect and evaluate trauma
B) To image soft tissues of the head and neck region
Which of the following is not a type of digital image receptor?
A) Photostimulable phosphor (PSP) plate
B) Scanner
C) Complementary metal oxide semiconductor active pixel sensor (CMOS-APS)
D) Charge-coupled device
B) Scanner
Which of these is used in indirect digital imaging?
A) Photostimulable phosphor (PSP) plate
B) Complementary metal oxide semiconductor active pixel sensor (CMOS-APS)
C) Charge-coupled device
D) Artificial intelligence
A) Photostimulable phosphor (PSP) plate
Which of the following is not an advantage of digital imaging over film-based imaging?
A) There is less radiation exposure.
B) It eliminates the need for a darkroom.
C) It is easier to place into position in the oral cavity.
D) Images may be manipulated to enhance interpretation.
C) It is easier to place into position in the oral cavity.
Which of these is false about photostimulable phosphor plates?
A) They use plates coated with a storage phosphor.
B) The plates are disposable.
C) They store x-ray energy until stimulated by a laser beam.
D) They are similar to film-based radiography in that they must be “developed” later.
B) The plates are disposable.
Which of these is not a limitation of digital imaging?
A) The need for plastic infection control barriers may hinder placement intraorally.
B) Smaller overall dimensions limit recording area.
C) The initial costs to convert from film-based imaging can be expensive.
D) System malfunction or computer crash may be possible.
A) The need for plastic infection control barriers may hinder placement intraorally.
The more pixels in a digital image, the…
A) lower the resolution and the sharper the image.
B) lower the resolution and the less sharp the image.
C) higher the resolution and the sharper the image.
D) higher the resolution and the less sharp the image.
C) higher the resolution and the sharper the image.
How many gray levels can a computer monitor display?
A) 8
B) 32
C) 256
D) 65,500
C) 256
Which of the following is false regarding a digital sensor?
A) It requires a different technique than a film packet.
B) It replaces an intraoral film packet.
C) It may be wired or wireless.
D) It is available in sizes similar to film packets.
A) It requires a different technique than a film packet.
Which digital image receptor uses plates coated with a storage phosphor to store the x-ray energy until stimulated by a laser beam?
A) Charge-coupled device
B) Photostimulable phosphor
C) Complementary metal oxide semiconductor
B) Photostimulable phosphor
How much less radiation exposure does digital radiography require compared to fast-speed film-based radiography?
A) 0 to 20 percent
B) 0 to 30 percent
C) 0 to 50 percent
D) 0 to 80 percent
C) 0 to 50 percent
A wide dynamic range means a wide range of exposure settings will produce an image of acceptable density and contrast. A narrow dynamic range means the exposure settings must be relatively precise. Which is true?
A) The first statement is true. The second statement is false.
B) The first statement is false. The second statement is true.
C) Both statements are true.
D) Both statements are false.
C) Both statements are true.
What determines the quality of a digital image?
A) Gray scale
B) Spatial resolution
C) Combination of pixels
D) All of the above
D) All of the above
Which image receptor is the least sensitive to radiation and requires more radiation exposure to produce an image?
A) CCD
B) CMOS-APS
C) PSP plate
D) Film
A) CCD
The size and number of pixels that make up a digital image determine the spatial resolution. Spatial resolution is measured in line pairs. Which is true?
A) The first statement is true. The second statement is false.
B) The first statement is false. The second statement is true.
C) Both statements are true.
D) Both statements are false.
C) Both statements are true.
There are two methods of acquiring a digital image.
True
CCD and CMOS-APS direct digital sensors work equally well at converting x-rays into an electronic signal that is sent to a computer.
True
Direct digital imaging uses film.
False
A digital image is the same as an analog image.
False
Each pixel is a single dot in a digital image.
True
Most digital imaging systems cannot be used with conventional x-ray machines.
False
Solid-state digital sensors are available wired or wireless.
True
CMOS-APS and CCD are types of direct digital sensors.
True
Line pairs refers to the total number of shades of gray visible in an image.
False
Digital radiography requires a computer and monitor to capture and view an image.
True
The lower the line pairs per millimeter, the better the spatial resolution.
False
The discernable separation of closely adjacent image details is referred to as “contrast.”
False
Artificial intelligence uses a computer to superimpose two standardized radiographic images, causing the like areas of the image to “cancel” each other out, leaving only the changes visible.
False
Using digital radiographic software to analyze bone around a dental implant is an example of artificial intelligence.
True
Film-based radiographs contain analog data.
True
The digital technology used in digital radiographic sensors is similar to that used in digital cameras and computer memory chips.
True
The x and y coordinates are used by the computer to reconstruct digital data obtained by the sensor into an image that can be viewed on the computer monitor.
True
If more radiation reaches the digital sensor, the gray value will decrease.
False
CCD and CMOS-APS digital image receptors very closely resemble film and capture x-ray energy in a manner similar to film.
False
Photostimulable phosphor plates are light sensitive.
True
What is the difference between a digital image and a radiograph?
A digital image has no physical form
Are digital radiography systems limited to intraoral images?
No. There are intraoral and extraoral digital imaging systems available.
Do digital imaging systems necessarily require a computer and monitor to capture and view an image?
Yes
By what mechanism are PSP plates reusable?
The images stored on PSP plates can be erased by exposing them to bright light. One image stored on the plate must be erased before the plate can be exposed again.
What is the purpose of digital imaging measuring software?
Linear and angular measurements obtained with a software “ruler” or measuring feature are useful in measuring the length of root canals during endodontic treatment and for estimating bone loss.
What is digital subtraction?
A technique that permits comparison of digital images to detect changes over time, and prior to and after therapeutic interventions. Digital subtraction merges two images of the same area, taken at two different times. The areas where change has occurred stand out conspicuously.
How can two images, taken over time, be compared using digital subtraction?
Two standardized radiographic images of the same area, taken at different times, are merged together electronically. Areas that are the same cancel each other out, leaving areas of change to stand out conspicuously.
Which requires less radiation to produce an image, digital or conventional film-based radiographs?
Digital radiography. Radiation exposure from digital imaging systems can be from 0 to 50 percent less than exposures from film-based dental radiography, depending on the film speed used.
What is the digital equivalent of film fog?
Electronic noise, an electrical disturbance that clutters the image, is the equivalent of film fog.
