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2010-11-18 07:43:46
Chapter twenty four

Digital radiography
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  1. radiograph image produced by conventional film
    analog image
  2. number of possible grey-scale combintations for each pixel (8 bit depth=28 or 256 shades of gray)
    bit depth image
  3. The sensor used in digital radiography transmits the information to a computor in analog form, and the computer converts it to digital form using what?
    analog-to-digital converter (ADC)
  4. unique 'filmless' imaging system in computer technology
    digital radiography
  5. What year was digital radiography introduced to dentistry?
  6. What is used in the digital radiography technique instead of film or processing?
    electronic sensor and computerized imaging system
  7. A solid state detector used in many devices (fax machine, home video camera, etc) in digital radiography, it is an image receptor found in the intraoral sensor.
    Charge-coupled device (CCD)
  8. a filmless imaging system; a method of capturing a radiographic image using a sensor, breaking it into electron pieces, and, presenting and storing the image using a computer
    digital radiography
  9. one feature of digital radiography; a method of reversing the gray-scale as an image is viewed; radiolucent images (normally black) appear white and radiopaque images (normally white) appear black.
    digital subtraction
  10. in digital radiography, to convert an image into a digital form that, in turn, can be processed by a computer
  11. a method of obtaining a digital image in which an intraoral sensor is exposed to x-rays to capture a radiographic image that can be viewed on a computer monitor
    direct digital image
  12. a method of obtaining a digital image in which an existing radiograph is scanned and converted into a digital form using a CCD camera
    indirect digital imaging
  13. a discrete unit of information. in digital electronic images, digital information is contained in, and presented as, discrete units of information (picture element)
  14. In digital radiography, a small detector that is placed intraorally to capture a radiographic image
  15. a method of obtaining a digital image in which the image is recorded on phosphor-coated plates and then placed into an electronic processor where a laser scans the plate and produces an image on a computer screen
    storage phosphor imaging
  16. What is the purpose of digital radiography?
    to generate images that can be used in the diagnosis and assessment of dental disease
  17. What are the 6 uses of digital radiography?
    • detect lesions, diseases, and contitions of the teeth and surrounding structures
    • confirm or classify suspected disease
    • provide info during dental procedures (root canal, implants, etc)
    • evaluate growth and development
    • illustrate changes secondary to caries, periodontal disease, or trauma
    • document the condition of a pt at a specific point in time
  18. a method of capturing a radiographic image using a sensor, breaking it into electronic pieces, and presenting and storing the image using a computer
    digital radiography
  19. in digital radiography, what term is used to describe the pictures that are produced on the computer screen?
  20. a small detector placed inside the mouth of the patient to capture the radiographic image
  21. In digital radiography the___________is used instead of intraoral dental film
  22. The x-ray beam is aimed to strike the sensor, then, an electronic charge is produced on the surface of the sensor; this electronic signal is___________, or converted into 'digital' form
  23. _____________is used to store the image electronically after it has been digitized by the sensor and processed by a computer
  24. true or false. The image is displayed within seconds and may be readily manipulated to enhance the appearance for interpretation and diagnosis
  25. Can extraoral images such as panoramic and cephalometric radiographs be used and taken in digital radiography?
  26. Does digital or conventional radiography require less radiation exposure? Why?
    digital, because less x-radiation is necessary to form a digital image on the sensor because the typical sensor is more sensitive to x-rays than conventional film
  27. Exposure time for digital radiography are______to_____ % less than that required for conventional radiography using E-speed film
    • 50
    • 80
  28. How many impulses are required in typical exposure time to produce an image for digital radiography? For E-speed intraoral film in conventional radiography?
    • 3 impulses (3/60 or 0.05 seconds)
    • 12 impulses (12/60 or 0.2 seconds)
  29. Name the 3 essential components of a direct digital imaging system
    • x-radiation source
    • intraoral sensor
    • computer
  30. True or false. The conventional radiation source is compatible with the digital imaging system. A standard x-ray unit that is adapted for digital radiography can still be functional for conventional radiography
    both statements are true
  31. When using a conventional x-radiation source with the digital imaging system, what must you adapt the x-ray unit timer to?
    1/100 of a second
  32. true or false. Intraoral sensors used in digital radiography may be wired or wireless
  33. the fact that the imaging sensor is linked by a fiber optic cable to a computer that records the generated signal
  34. with wired systems, the cables vary in length from ____to_____feet
    • 8
    • 35
  35. the_________the cable, the more limited the range of motion will be
  36. the fact that the imaging sensor, a phosphor-coated plate, is not linked by a cable
  37. What are the 3 types of direct sensor technologies that exist?
    • charged-coupled device (CCD)
    • complementary metal oxide semiconductor/active pixel sensor (CMOS/APS)
    • charge injection device (CID)
  38. Which of the 3 direct sensor technologies is the most commonly used?
    charge-coupled device (CCD)
  39. When was the CCD technology first developed?
    in the 1960's
  40. Name 4 examples of other devices that CCD is used in.
    • fax machines
    • home video cameras
    • telescopes
    • microscopes
  41. a solid state detector that contains a silicon chip with an electronic current embedded in it
  42. What part of the CCD is sensitive to x-rays or light?
    the silicon chip
  43. The electrons that make up the silicon CCD can be visualized as being divided into an arrangement of blocks or picture elements known as__________
  44. a small box or 'well' into which the electrons produced by the x-ray exposure are deposited.
  45. What is the digital equivalent to silver crystal used in conventional radiography?
    a pixel
  46. film emulsion contains a____________arrangement of silver crystals, a pixel is structured in an_______ arrangement
    • random
    • ordered
  47. The CCD is how large in individual pixel size? And contains how many pixels?
    • 640 x 480
    • 307,200
  48. What is the function of all the pixels of the CCD?
    to sense transmitted light and translate it into an electronic image
  49. x-ray photons that come into contact with the CCD cause what to happen?
    electrons to be released from the silicon and produce a corresponding electric charge
  50. What causes electrons to be released from the silicon and produce a corresponding electronic charge?
    the x-ray photons that come in contact with the CCD
  51. Why does each pixel arrangement, or electron potential well, contain an electronic charge proportional to the number of electrons that reacted within the well?
    because the x-ray photons that come into contact with the CCD cause electrons to be released from the silicon and produce a corresponding electronic charge
  52. Each pixel arrangment, or electronic potential 'well' contains an electronic charge proportional to what?
    the number of electrons that reacted within the well
  53. When is an electronic latent image produced in digital radiography?
    when x-rays activate electrons and produce electronic charges
  54. Where is the latent image transmitted and stored?
    on the computer
  55. What type of sensor technology is the standard in the making of semiconductor chips?
    complementary metal oxide semiconductor/active pixel sensor (CMOS/APS)
  56. When did the CMOS become useful in digital radiography?
    when the APS was developed
  57. What is the name of the manufacturer that uses a CMOS/APS sensor instead of a CCD, and claims that it has 25% greater resolution?
    shick technologies
  58. Shick technologies says that CMOS/APS has a__________greater resolution.
  59. What are 2 additional advantages of the CMOS/APS technology?
    • the chip is less expensive to produce
    • offers greater durability than the CCD
  60. sensor technology, a silicon based solid state imaging receptor much like the CCD, but is structurally different from the CCD
    charge injection device (CID)
  61. What is the name of the person who introduced to the charge injection device? And what device did he use it with?
    • Welch Allyn
    • intraoral video platform
  62. true or false. No computer is required to process that images from the charge injection device (CID)
  63. What are 4 system features of the charge injection device?
    • CID x-ray sensor
    • cord
    • plug inserted into:
    • reveal light source on the camera platform
  64. a____________is used to store the incoming electronic signal.
  65. the____________is responsible for converting the electronic signal from the sensor into a shade of gray that is viewed on the monitor.
  66. Each pixel is represented numerically in the computer by________and_________and__________ of_____.
    • location
    • level
    • color
    • gray
  67. What does the range of numbers for a pixel vary from? And how many shade's of gray does that create?
    • 0-255
    • 256
  68. the range of numbers for a pixel in shades of gray is referred to as what?
    pixel's gray-scale resolution
  69. How many shades of gray can a human eye appreciate?
    only 32 (small compared to the 256 pixel's gray scale resolution)
  70. What does the pixel's gray scale resolution technology allow the dental professional to do in regards to radiation exposure to the patient?
    It allows them to enhance contrast and density without additional radiation exposure to the patient
  71. What are 3 things the computer does with the information received from the sensor?
    • digitizes
    • processes
    • stores
  72. The computer monitor allows for_____________viewing of the exposure to the sensor.
  73. How long does it usually take for an image to be recorded on a computer monitor?
    .5-120 seconds
  74. A digital system feature that allows the operator to view and compare multiple images on the same screen
    split screen technology
  75. split screen technology is helpful in the comparison and evaluation of disease progression involving what 2 conditions?
    • caries
    • periodontal disease
  76. Digital systems provide a feature that allows specific images to be magnified up to_________times their original size