RAD-139 CH.4 RADIATION PROTECTION QUANTITIES & UNITS

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anatomy12
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264168
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RAD-139 CH.4 RADIATION PROTECTION QUANTITIES & UNITS
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2014-03-12 18:12:07
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  1. what is the unit for measurement of expsure to x and gamma radiation
    roentgen
  2. what does rem stand for
    radiation equivalent man
  3. fluorscopic entrance exposure rates are measured in _____
    roentgen
  4. what other device meausres radiation in air
    pocket dosimeter (R)
  5. we express exposure(X) as
    what is the definition of this unit
    • roentgen
    • measurement of radiation in air
  6. what is an ionization chamber used for
    measure radiation exposure
  7. what is the unit for absorbed dose
    what is absorbed dose
    • RAD or GY
    • the amt of energy per unit mass absorbed by an irradiated object
  8. what energy is responsible for any biological damge resulting from exposure
    absorbed energy
  9. how do reduce absorbed dose to patient
    use high kvp and low mas
  10. what technical affects absorption into the body
    low kvp
  11. the amoutn of absorption is is dependent on what three things
    • atomic # of tissue composing the structure
    • mass density of the tissue
    • energy of the incident photon
  12. Absorption increases when:
    atomic # ______
    Mass density ______
    Photon enrgy _____
    • increases
    • increases
    • decreases
  13. what is radiolysis
    when radiation splits a water molecule in the body
  14. what is LET
    linear energy transfer is the amt of ionizations per unit length of tissue
  15. the majority of the energy is emitted  with ____ of the maximum kv
    1/3 or 30-40 percent
  16. what absorbs more ionizing radiation bone or soft tissue
    bone
  17. rad to gy?
    gy to RAD?
    REM to Sv
    Sv to REM
    • divide by 100
    • mult. by 100
    • divide by 100
    • mult. by 100
  18. mill to no milli
    no milli to milli
    • divide by 1000
    • mult. by 1000
  19. Radiation with high LET transfers ______ amounts of energy to a ______ area
    • large
    • small
  20. High LET has ____ penetration
    low LET has _____ penetration
    • low penetration but more energy in a closed area
    • high penetration but less energy or ionizations per unit length
  21. list examples of high LET and low LET
    • high LET = alpha and beta particles
    • low LET = x and gamma radiation
  22. Dose equivalent or Equivalent dose, effective dose is measured in what unit
    • REM or Sv or Eqd
    • rem or Sv
  23. what is dose equivalent
    the product of the average absorbed dose in a tissue or organ and its associated radiation weighing factor (Wr) (type of radiation)
  24. the Wr stand for what and is the same as what
    • Wr= weight of radiation (weight of beta alpha and gamma radiation)
    • sames a quality factor of particles
  25. what are stochastic effects
    non threshold, randome probability of occuring biological effects of ionizing radiation such as cancer & genetic abnormalties
  26. what are non stochastic effects
    these effects have a threshold you would need a certain amount of radiation (threshold) to get cataracts, hair loss or burns
  27. what is the effective dose(EfD)
    what two things does it incorporate
    the sum of the weighted equivalent doses for all irradiated tissues or organs, it includes the type of radiation used(xray gamma neutron) and the variability in radiosensitivity of the specific organ or body part irradiated thru the use of proper weighting factors
  28. what unit is the tissue weighing factor expressed as
    what is the definition of this value
    • Wt
    • it is a vlue that denotes the % of the summed stochastic riscks (cancer+genetic)stemming from tissue irradiation
    • it accounts for the risks to the entire organism brought on by irradiation of individual tissues and organs
  29. what is collective effective dose (ColEfd)
    what is its SI unit
    • describes radiation exposure of a population or group from low doses of different sources of ionizing radiation
    • person-sievert
  30. what is the formula for effective dose:
    formula for equivalent dose:
    formula for dose equivalent:
    • DxWrxWt
    • DxWr
    • DxQ (quality factor)
  31. what does air kerma stand for (3 acronyms)
    what is it
    • kinetic energy in matter
    • kinetic energy released in material
    • kinetic energy released per unit mass
    • an SI quantity that can be used for radiation concentration transferred to a point that maybe at the surface of a patients or radiographers body
  32. coulomb per kilogram is the SI unit for what?
    radiation in exposure in air
  33. surface integral dose
    total amount of radiant energy transferred by ionizing radiation to the body during radiation exposure
  34. which dose involves the tissue weighting factor
    effective dose
  35. which dose involves the radiation weighting factor
    equivalent dose
  36. which does deals with the amoutn of radiation absorbed in an irradiated object per unit mass and is measured in rad or gy
    absorbed dose
  37. how is one rad expressed mathematically
    1rad=100 erg/g
  38. what is dap and what does it stand for
    dose area product is the sum of air kerma over the exposed area of the patients body
  39. what contains a known quantity of air with precisely measured temperature and humidity
    free air ionization chamber

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