radiology

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Author:
sweetpea281
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50312
Filename:
radiology
Updated:
2010-11-17 20:40:33
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ch24
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digital radiography
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  1. when was digital radiography introduced into dentistry?
    1987
  2. No ______ is required with digital radiography like film
    processing
  3. digital radiography produces what kind of image?
    instant
  4. what two things are used to in digital radiography?
    electronic sensor and computerized imaging system
  5. what is a radiographic image produced b conventional film
    analog image
  6. what is the number of possible gray scale combinations for each pixel
    bit depth image
  7. what is a solid state detector used in many devices, in digital radiography it is an image receptor found in the intraoral sensor?
    charge-coupled device
  8. filmless imaging system; 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
  9. an image composed of pixels
    digital image
  10. one feature of digital radiography; a method of reversing the gray scale as an image is viewed; radiolucent images appear white and radiopaque images appear black?
    digital subtraction
  11. in digital radiography to convert an image into a digital form that in turn can be processed by a computer
    digitize
  12. method of obtaining a digital image in which an intraoral sensor is exposed to xrays to capture a radiographic image that can be viewed on a computer monitor
    direct digital imaging
  13. 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
  14. measurement used to evaluate the ability of the computer to capture the resolution of a radiographic image
    line paires/millimeter (lp/ml)
  15. a discrete unit of information. In digital electronic images, digital information is contained in and presented as discrete unites of information also termed picture element
    pixel
  16. in digital radiography a small detector that is placed intraorally to capture a radiographic image
    sensor
  17. 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
  18. the purpose of digital radiography is to generate _____ that can be used in the _____ and _____ of dental disease
    • images
    • diagnosis
    • assessment
  19. what are the uses for digital radiograph? (6)
    • detect lesions, disease and conditions of the teeth and surrounding structures
    • confirm or classify suspected disease
    • provide info during dental procedures
    • evaluate growth and development
    • illustrate changes secondary to caries, perio or trauma
    • document the condition of a patient at a specific point in time
  20. In digital radiography a ____ is placed inside the mouth of the patient to capture the radiographic image
    sensor
  21. when the xray beam strikes the sensor what happens?
    an electronic charge is produced on the surface of the sensor and the electronic signal is digitized and the sensor transmits the info to a computer in analog form and the computer converts it to digital form using an analog to digital converter and then the computer stores and displays the info within seconds
  22. what kind of charge is produced on the sensor when the xray beam hits it?
    electronic charge
  23. what form does the sensor transmit the info to the computer?
    analog form
  24. what must the computer do to the info the sensor has given it?
    convert it from analog to digital with a converter (ADC) and then store the image and display it
  25. with digital radiography what is it called instead of a radiograph or xray film?
    image
  26. digital radiography is not limited to ______ images
    intraoral
  27. t/f digital radiography requires more x-radiation than conventional radiography
    FALSE! sensor is more sensitive
  28. the exposure times for digital radiography are what % less than conventional?
    50 to 80%
  29. ____ impulses are used for digital radiography vs ____ for conventional
    3 vs 12
  30. with less exposure time the absorbed does to the patient is ____
    lower (significantly)
  31. what is the x-radiation source for digital radiography?
    conventional dental xray unit
  32. what must does the time frame need to be for digital?
    1/100 of a second
  33. t/f once the conventional unit has been altered for digital it can no longer be used as a conventional dental unit
    FALSE! it can still be used for conventional
  34. what are the three exxential components of a direct digital imaging system?
    • x-radiation source
    • intraoral sensor
    • computer
  35. some sensors are _____, _____ and _____ but others mimic conventional film in their size and flexibility.
    thick, bulky and rigid
  36. what are the sensor sizes similar to?
    size 0, 1, 2 and 4 intraoral films
  37. intraoral sensors can be ____ (linked by a fiberoptic cable) or ____ (not linked by a cable)
    • wired
    • wireless
  38. what are the three types of direct sensor technologies
    • charge-coupled device
    • complementary metal oxide semiconductor/active pixel sensor
    • charge injection device
  39. what is one of hte most common image receptors used in dental digital radiography?
    charge coupled device (CCD)
  40. _____ _____ ______ uses special fabrication that is expensive to manufacture
    charge coupled device
  41. what other devices is CCD technology used in
    • fax machines
    • home video cameras
    • microscopes
    • telescopes
  42. what type of direct sensor technology is a solid state detector that contains a silicon chip with an electronic circuit embedded in it
    charge coupled device (CCD)
  43. the silicon chip in CCD is sensitive to what?
    x-rays or light
  44. how are the electrons arranged on the silicon CCD
    divided into ordered pizels (like silver crystals)
  45. are the pixels for the CCD arranged randomly or ordered?
    ordered
  46. the CCD is ____ x ____ individual pixels in size
    640 x 480
  47. how many pixels does the CCD contain?
    307,200
  48. the CCD senses transmitted _____ and translates it into ______ message
    • light
    • electronic
  49. what does the xray photon cause for the CCD?
    electrons to be released from the silicon and to produce a corresponding charge
  50. what does CMOS/APS stand for?
    complementary metal oxide semiconductor/active pixel sensor
  51. what manufacturer uses CMOS/APS?
    Schick Technologies
  52. what does Schick Technologies claim about CMOS/APS?
    25% greater reolution
  53. CMOS/APS claims to have _____% greater resolution
    25%
  54. the complementary metal oxide semiconductor/active pixel sensor (CMOS/APS) is ____ expensive to produce and offers _____ durability
    • less
    • greater
  55. what does CID stand for?
    Charge injection device
  56. CID like CCD is what kind of receptor?
    silicon based solid state imaging receptor
  57. t/f no computer is required for charge injection device (CID)
    true (its magic)
  58. what is CID produced to work with?
    reveal intraoral video camera docking platform
  59. how are CID images viewed?
    on the system monitor
  60. CID pictures can be printed with a _____ _____ printer
    color video
  61. how can the pictures be saved with CID
    on a computer file or a video disk recorder
  62. what is the computer used for with digital radiography?
    • used to store incoming electronic signals
    • converts the electronic signal from sensor into a shade of gray
  63. what does the computer convert the electronic signal into?
    shade of gray
  64. where are digital images viewed with a computer?
    computer monitor
  65. how are the pixels represented on the computer?
    mumerically by location and level of color of gray
  66. what is the range of numbers for pixels?
    varies from 0-255
  67. how many shades of gray do the pixels show?
    256
  68. how many shades of gray can the human eye see?
    32
  69. what is the gray scale resolution?
    0-255 pixel range totaling in 256 shades of gray
  70. the number of possible gray scale combinations per pixel is known as?
    bit-depth image
  71. what does the computer software allow?
    manipulation of pixels (enhancing contrast density)
  72. t/f software requires more radiation exposure to the patient
    FALSE! it allows for manipulation of pixels without additional exposure to patient
  73. the computer ____, ____ and stores information received from the ____
    • digitizes
    • processes
    • sensor
  74. the image is viewed on the monitor in ____ to ____ seconds
    .5-120 seconds
  75. the computer allows for a magnification of ___x
    4x
  76. what measurements can be made from the image on the monitor?
    linear and angular measurements
  77. what allows for the operator to view and compare multiple images on the same screen?
    split screen technology
  78. what equipment is needed for direct digital imaging?
    • xray machine
    • intraoral sensor
    • computer monitor
  79. what are the components needed for indirect digital imaging?
    CCD camera and compouter
  80. t/f indirect digital imaging is not as good of quality as direct digital imaging
    True!!
  81. what is a second type of indirect digital imaging?
    storage phosphor imaging
  82. is storage phosphor imaging wired or wireless
    wireless
  83. what does storage phosphor imaging use instead of a sensor?
    reusable imaging plate coated with phosphors
  84. what is the storage phosphor plate similar to?
    intensifying screens
  85. how is the image cleared from a storage phosphor plate?
    light
  86. how are storage phosphor plates digitized?
    high speed scanner converts information into electronic files
  87. how long does the extra step of scanning during storage phosphor imaging take?
    30 to 5 min
  88. what must the sensor be covered with before use? why?
    • disposable barrier
    • it cannot be sterilized
  89. what guidelines should you follow when taking digital radiography?
    manufacturers recommendations
  90. what is the preferred exposure method for digital radiography, why?
    • paralleling technique
    • for dimensional accuracy of images and ease of standardizing such images
  91. why must film holders be used for digital radiography?
    stabilize the sensor in the mouth
  92. what are 7 advantages to digital radiography?
    • superior gray scale resolution
    • reduced exposure to xradiation
    • increased speed of image viewed
    • lower equipment and film cost
    • increased efficiency
    • enhancement of diagnostic image
    • effective patient education tool
  93. what are 5 disadvantages to digital radiography
    • initial setup cost
    • image quality
    • sensor size
    • infection control
    • legal issues

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