Radiology Chapter five

  1. what is the affect of X-radiation on cells?
    it causes biological changes in living cells, and adversely affects all living tissue
  2. When can patient protection from radiation be used?
    prior to, during, and after x-ray exposure
  3. What is the first step in limiting the amount of radiation a dental pt recieves?
    proper prescribing of dental radiographs
  4. Who is responsible for prescribing dental radiographs? And what are the dental radiograph prescriptions made for?
    • The dentist
    • number
    • type
    • frequency
  5. How should the dentist determine how to prescribe radiographs?
    • based on the pt's individual needs
    • according to guidelines from the FDA for prescribing dental radiographs
  6. What must the dental x-ray tubehead be equipt with for patient protection
    • aluminum filters
    • lead collimator
    • position indicating device
  7. 2 types of filtration used in the dental x-ray tubehead
    • inherent filtration
    • added filtration
  8. takes place whtn the primary beam passes through the glass window of the x-ray tube, the insulating oil, and the tubehead seal. The inherent filtration of the dental x-ray machine is equivalent to approximately 0.5 to 1.0mm of aluminum.
    inherent filtration
  9. does inherent filtration alone meet the standards regulated by state and federal law?
    no, so added filtration is required
  10. refers to the placement of aluminum disks in the path of the x-ray beam between the collimator and the tubehead seal in the dental x-ray machine. They can be added to the tubehead in 0.5-mm increments. Their purpose is to filter out longer wavelength, and low energy x-rays from the x-ray beam.
    Added filtration
  11. the___________energy and ________________wavelength x-rays are harmful to the pt and not usedful in diagnostic radiography.
    • low
    • long
  12. _______________of the x-ray beam results in higher energy, and more____________ useful beam.
    • filtration
    • penetrating
  13. the required thickness of this is regulated by state and federal law.
    inherent and added filtration together.
    total filtration
  14. state and federal law requirements for total filtration
    • machine operating at or below 70 kVp require a minimum total of 1.5 mm aluminum filtration
    • machines operating at above 70 kVp require a minimum total of 2.5 mm aluminum filtration
  15. used to restrict the size and shape of the x-ray beam and to reduce the patient exposure
  16. lead plate with a hole in the middle fitted directly over the opeing of the machine housing where the x-ray beam exits the tubehead
  17. this collimator restricts the sized of the x-ray beam to an area slightly larger than a size 2 intraoral film and siginificantly reduces patient exposure
    rectangular collimator
  18. this collimator produces a cone shaped beam that is 2.75 inches in diameter, considerably larger than a size 2 film
    circular collimator
  19. appears as an extension of the x-ray tubehead and is used to direct the x-ray beam
    position indicating device
  20. three types of PIDs
    • conical
    • regular
    • round
  21. appears as a closed, pointed plastic cone, when x-rays exit from it they penetrate the plastic and produce scatter radiation. Not recommended
    Conical PID
  22. Why aren't the conical PIDs used in dentistry anymore?
    because they produced too much scatter radiation
  23. What lengths are round and rectangular PIDs commonly available in?
    • short 8-inch
    • long 16-inch
  24. Which lenght of PID is preferred and why?
    • the long PID
    • because less divergence of the x-ray beam occurs
  25. Of the 3 types of PIDs, which is most effective in reducing pt exposure?
    rectangular type
  26. name devices used during x-ray exposure to protect the pt.
    • thyroid collar
    • lead apron
    • fast film
    • film holding devices
  27. a flexible lead shield that is placed securely around the pts neck to protect the thyroid gland from scatter radiation. The lead prevents radioation from reaching the gland and protects the highly radiosensitive tissues of the thyroid.
    thyroid collar
  28. When is the use of the thyroid collar recommended?
    during all intraoral films
  29. why is the use of the thyroid collar not recommended for extraoral films?
    because it obscures information on the film and results in a nondiagnostic radiograph
  30. a flexible shield that is placed over the patients chest and lap to protect the reproductive and blood-forming tissues from scatter radiation; it prevents the radiation from reaching these radiosensitive organs.
    lead apron
  31. When is the use of a lead apron recommended?
    for all intra and extraoral films
  32. What is the single most effective method of reducing a pt's exposure to x-radiation?
    the use of fast film
  33. What is the fastest film speed available?
    F-speed; reduces exposure 20% over E-speed
  34. Extaspeed
  35. helps to stabilized the film position in the mouth and reduces the chance of movement. It also eliminates the need for the pt to hold the film in place.
    film-holding devices
  36. How can the dental radiographer control the exposure factors?
    • adjust the:
    • kilovoltage peak
    • milliamperage
    • time settings
  37. a setting of ____________kVp keeps pt exposure to a minimum
  38. Helps to ensure the diagnostic quality of films and reduce the amount of exposure a patient recieves
    proper technique
  39. all retakes must be____________!
  40. to produce diagnostic films one must what?
    • have a thourgough knowledge of the techniques used and how to expose
    • have an organized routine for taking films
  41. techniques used most often in x-radiation
    • paralleling
    • bisecting
    • bitewing
  42. How is pt protection implemented after radiation exposure?
    meticulous and proper film handling and film processing to prevent the existence of artifacts and other things on the film that will render them nondiagnostic, and therefor result in retaking films
  43. Why must the dental radiographer also use proper protection measures for themselves?
    • to avoid occupational exposure to radiation:
    • primary radiation
    • leakage radiation
    • scatter radiation
  44. What is the main rule for operator protection guidelines?
    the dental radiographer must aviod the primary beam
  45. What is the distance recommendation for the dental radiographer?
    stand atleast 6 feet away from, and perpendicular to the beam; or used a protective barrier
  46. What are the position recommendations for the dental radiographer?
    • stand perpendicular to the beam
    • never hold a film in place for a pt during x-ray exposure
    • never hold the tubehead during x-ray exposure
  47. What are the shielding recommendations for the dental radiographer?
    stand behind a protective barrier such as a wall consisting of several thickness layers of common construction materials such as dry wall
  48. the monitering of equipment and dental personnel; can identify excess occupational exposure
    radiation monitering
  49. What must dental x-ray machines be monitered for?
    leakage radiation
  50. any radiation, with the exception of the primary beam, that is emitted from the dental tubehead
    leakage radiation
  51. measures the amount of x-radiation that reaches the body of the dental radiographer
    film badge
  52. What does the film badge consist of? When and where should it be worn and stored?
    • a piece of radiographic film in a plastic holder
    • worn at waist level
    • whenever the radiographer is exposing films
    • stored when radiographer is undergoing x-ray exposure
    • stored in a radiation safe place
  53. has been established at both the state and federal levels to protect the patient, operator, and general public from radiation hazards.
    Radiation safety legislation
  54. When and why was the radiation control for health and safety Act enhanced?
    • 1968
    • to standardized the performance of the x-ray equipment
  55. When and why was the consumer-patient radiation health and safety act at the federal level enhanced?
    • 1981
    • to address the issues of the education and certification of persons using radiographic equipment
  56. True or False. radiation legislation differs greatly from state to state so the dental radiographer must be familiar with the laws that apply to their workplace.
  57. defined by the national council on radiation protection and measurements as the maximum dose equivalent that a body is permitted to recieve in a specific period of time. The dose of radiation that the body can endure with little or no injury
    maximum permissable dose
  58. What is the current MPD for occupationally exposed persons?
    5.0 rem/year
  59. what is the current MPD for nonoccupationally exposed persons?
    0.5 rem/year
  60. what is the MPD for an occupationally exposed pregnant women?
    0.5 rem/year
  61. accumulated lifetime radiation dose that occupationally exposed workers must not exceed.
  62. what is the formula that determines MAD?
    MAD= (perosons age in years - 18) x 5 rem/year
  63. How much radiation does one recieve from a tv set at 1 inch?
    0.5 mrem/yr
  64. how much radiation does one recieve from airline travel at 39,000 ft?
    0.5 mrem/ yr
  65. how much radiation does one recieve from nuclear power plants at plant boundary?
    0.6 mrem/yr
  66. how much radiation does one recieve from natural gas in a home?
    9 mrem/yr
  67. How much radiation does one recieve from terrestrial backgrounds (rocky mountains)?
    40 mrem/yr
  68. How much radiation does on recieve from dental x-rays?
    10 mrem
  69. How much radiation does one recieve from head/neck x-rays?
    20 mrem
  70. how much radiation does one recieve from chest x-rays (average)?
    8 mrem
  71. How much radiation does one recieve from radionuclides in the human body (i.e. potassium)
    39 mrem/yr
  72. how much radiation does one recieve from building material (concrete)?
    3 mrem/yr
  73. how much radiation does one recieve from drinking water?
    5 mrem/yr
  74. states that all exposure to radiation must be kept to a minimum or "as low as reasonably achievable"
    ALARA concept
  75. What are some ways that patient education about x-radiation are implemented?
    • informal discussion
    • printed material
Card Set
Radiology Chapter five
radiation protection