Chapter 18 review questions/summary/additional info CRB

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Chapter 18 review questions/summary/additional info CRB
2012-11-28 22:15:23
Chapter 18 review questions summary additional info CRB

Chapter 18 review questions/summary/additional info CRB
Show Answers:

  1. Activity is defined as:
    rate of nuclear decay
  2. The source of ionizing radiation that contributes the most to exposure of the general population in the US is:
    natural background radiation
  3. Which type of device is best suited for output measurements of radiation therapy equipment?
    ionization chamber
  4. Stochastic, or non threshold, effects of radiation exposure do not include:
    A. cancer induction
    B. genetic effects
    C. birth defects
    D. cataract formation
    D. cataract formation
    (this multiple choice question has been scrambled)
  5. Exposure of which people would contribute the most of the genetically significant dose?
    A. 50 yr old woman
    B. 70 yr old man
    C. 20 yr old woman
    D. all contribute equally
    C. 20 year old woman
    (this multiple choice question has been scrambled)
  6. The annual effective dose equivalent limit for radiation wokers is:
    50 mSv
  7. A G-M detector is 2 m from a small brachytherapy source and measures an exposure rate of 10 mR/hr. What exposure would you expect to measure if the detector were moved to 4 m from the source?
    • 2.5 mR/hr
    • (10 divided by 4)
  8. Energy absorbed per unit mass
    absorbed dose
  9. Ionization per unit mass of air by photons
  10. Short-range, relatively heavy-mass, high-LET particle
    alpha particle
  11. What are the 2 major sources of radiation exposure in the radiation therapy dept?
    • megavoltage treatment machines (linear accelerators)
    • brachytherapy sources
  12. Regardless of which models are used to estimate the risks of radiation exposure, it is universally agreed that the less radiation received, the ____ the risk.
  13. In keeping with the _____ concept, every means should be taken to reduce individual exposure.
  14. Practical radiation protection from external beam radiation should include the time-honored methods of:
    • time
    • distance
    • shielding
  15. A resurgence in the use of ________ sources requires the radiation therapy practitioner to be prepared to demonstrate a comprehensive knowledge of its uses in terms of radiation ____ and ____.
    • brachytherapy
    • safety
    • protection
  16. Safety equipment must be tested ____ to ensure that it operates properly when needed.
  17. What are the fundamental techniques for radiation protection?
    • time
    • distance
    • shielding
  18. Which dosimeters have largely replaced film badge dosimeters for personnel monitoring?
    • OSL
    • Optically Stimulated Luminescence
  19. The overall risk of exposure to radiation is approximately ____ in _____ persons per rem.
    7 in 10,000
  20. What are the most common types of ionizing radiation used in radiation therapy? (3)
    • X-rays
    • gamma rays
    • electrons
  21. NCRP Recommendation:
    Occupational exposures (annual) for:
    -Effective dose equivalent limit (stochastic effects)
    50 mSv (5 rem)
  22. NCRP Recommendation:Occupational exposures (annual) for:
    Dose equivalent limits for tissues and organs (non stochastic effects)
    -Lens of eye
    -All others (breast, lung, gonads, skin, extremities)
    • Lens of eye - 150 mSv (15 rem)
    • All others -  500 mSv (50 rem)
  23. NCRP Recommendation:Occupational exposures (annual) for:
    -Guidence: cumulative exposure
    10 mSv x age in years (1 rem x age in yrs)
  24. NCRP Recommendation: Public exposures (annual) for:
    -Effective dose equivalent limit, continuous or frequent exposure
    -Effective dose equivalent limit, infrequent exposure
    • 1 mSv (0.1 rem)
    • 5 mSv (0.5 rem)
  25. NCRP Recommendation: Embryo-fetus exposures for:
    -Total dose equivalent limit
    -Dose equivalent in a month
    • 5 mSv (0.5 rem)
    • 0.5 mSv (0.05 rem)
  26. Number of patients per week x amount of radiation for each:
    W - Workload
  27. Fraction of time the beam is aimed at a particular wall:
    U - primary beam use factor for each wall
  28. Fraction of time area will be occupied:
    T - Occupancy factor
  29. Distance from the source of radiation to occupied area:
    d - Distance
  30. Limit for occupied area; radiation worker equivalent limit or general public:
    Effective dose
  31. As expected, the less _____ one is exposed to radiation, the less dose is acquired
  32. Increasing the ___ from a source of radiation can drestically reduce the radiation exposure.