1. when x-rays strike pt tissues ______ results
  2. true or false. All ionizing is harmful, and biological change from dental x-radiation is small, byt does still have biologic damage
    both statements are true
  3. Ionization of water results in the production of hydrogen and hydroxyl _____ _______
    free radicals
  4. suggests that cell damage results when ionizing radiation directly hits critical areas, or targets within the cell (DNA)
    direct theory
  5. suggests that x-ray photons are absorbed within the cell and cause the formation of toxins, which in turn damage the cell
    indirect theory
  6. When dose and damage of radiation are plotted on a graph, what type of relationship is seen?
    linear, nonthreshold
  7. true or false. there is NO safe amount of radiation, in dental radiation, damage always does occur
  8. effects that occur as a direct function of dose; the probability of occurence increases with dose, but the severity of effects does not depend on the magnitude of the absorbed dose; they do not have a dose threshold
    stochastic effects
  9. cancer induction and genetic mutations are what type of effects?
  10. effects that have a threshold and increase in severity with increasing absorbed dose
  11. erythema, loss of hair, cataract formation, and decreased fertility are examples of what effect?
  12. Why do high dose rates cause more damage?
    because the tissues don't have enough time to repair themselves
  13. result from exposure to a nuclear accident or atomic bomb - associated with large amounts of radiation in small amounts of time
    short-term effects
  14. effects that appear after years and years, associated with small amounts of radiation absorbed repeatedly over a long period of time - linked to the induction of cancer, birth abnormalities, and genetic defects
    long term effects
  15. All cells in the body except the reproductive cells
    somatic cells
  16. reproductive cells
    genetic cells
  17. effects seen in the person irradiated and not transmitted to future generations
    somatic effects
  18. effects not seen in the person irradiated, but passed to future generations
    genetic effects
  19. What are radiosensitive cells?
    • blood cells
    • immature bone cells
    • young bone cells
  20. What cell is most sensitive to radiation?
    small lymphocyte (blood cells)
  21. what are radioresistant cells?
    • cells of bone
    • muscle
    • nerve
  22. What are radiosensitive organs?
    • lymphoid tissue
    • bone marrow
    • testes
    • intestines
  23. What are radioresistant tissues?
    • salivary glands
    • kidney
    • liver
  24. Critical organs in dental radiography include:
    • skin
    • thyroid gland
    • lens of eye
    • bone marrow
  25. a way of measuring radiation exposure by the amount of ionization that occurs in air
  26. The amount of energy absorbed by a tissue; how is it measured?
    • Dose
    • rad (radiation absorbed dose)
  27. How much radiation reduction do you get from using f-speed film?
  28. A longer source to flim distance will _______ pts exposure to radiation
  29. true or false. The Roentgen (R) measures the amount of energy that reaches the surface of an organism, and the amount of radiation absorbed
    FALSE! It does NOT measure the amount of radiation absorbed!
  30. SI unit that measures the number of electrical charges, or ion pairs in 1 kg of air
  31. What measurement is used to compare the biological effects of different types of radiation?
    dose equivalent
  32. the product absorbed dose (in rads) and quality factor specific for the type of radiation; the traditional unit of the dose equivalent
    Rem - roentgen equivalent in man
  33. a _____ _______ or dimensionless multiplier is used to place the exposure effects of different types of radiation on a common scale
    Quality factor
  34. SI unit equivalent of the rem is __________
    sievert (sv)
  35. SI unit equivalent of the rad is ________
    gray (gy)
  36. a form of ionizing radiation that is ubiquitous in the environment, and which humans are exposed to daily
    background radiation
  37. Radiation that originates from the stars and the sun, and the higher the elevation, the more of this you recieve
    cosmic radiation
  38. radiation that is emitted from radioactive materials present in the earth and air including potassium and uranium
    terrestrial radiation
  39. What type of radiation is the single largest contributor to artificial radiation?
    medical radiation
  40. true or false. Risk estimates suggest that death is more likely to occur from common activities than from the dental radiographic procedures, and that cancer is far more likely to be unrelated to radiation exposure
  41. The use of a rectangular collimator reduces absorbed radiation dose by ______ %
    60-70 %
Card Set
ch. four, twelve