Unit 3 (Radiation Quantities & Units)

  1. Who discovered x-ray and when?
    • Wilhelm Conrad Roentgen
    • November 8, 1895
  2. What was the subject of the first documented x-ray?
    Mrs. Roentgen's hand
  3. When were the first reports of injury due to x-ray?
    early 1896
  4. Who was the first person to die from causes due to radiation exposure?
    • Clarence Madison Dally (glassblower, tube maker, assistant to Mr. Edison)
    • October 1904
  5. Who invented the fluoroscope?
    Thomas A. Edison
  6. How was Thomas Edison affected by the death of his assistant, Clarence Madison Dally?
    It caused him to end his research with x-ray.
  7. When were deaths of physicians who worked with radiation first reported?
    as early as 1910
  8. Occupational exposures contributed to the following disorders/conditions:
    • radiodermatitis (which often developed into cancer)
    • aplastic anemia
    • leukemia
  9. When was the first attempt to determine a workable unit of measuring radiation?
    • 1921
    • it was unsuccessful.
  10. What was the name of the first group that attempted to limit exposure to radiation by determining a workable unit of measurement for it?
    the British X-Ray and Radium Protection Committee
  11. From 1900-1930, what was the unit of measurement for radiation exposure and how was it determined?
    • skin erythema dose
    • determined by the degree of reddening of the skin
  12. Which gender typically has a higher tolerance level for radiation in comparison to the other?
  13. To have the same erythema dose, someone naturally dark would need more or less radiation exposure than someone very light?
  14. Name the even that occurred and the group that formed in 1925:
    • the First International Congress of Radiology
    • International Commission on Radiation Units and Measurements (ICRU)
  15. Name the event that occurred in 1928 and its two main accomplishments:
    • the Second International Congress of Radiology:
    • the "roentgen" was determined as the unit of radiation measurement
    • the International X-Ray and International Commission on Radiological Protection (ICRP) was established
  16. What are Somatic Effects:
    • also known as early or acute
    • effects that appear within minutes, hours, days, or weeks of exposure
    • effects occurring during a person's lifetime
  17. During an early era of understanding, it was thought that if levels of radiation were kept below the _____________, there would be no adverse effects from radiation exposure.
    threshold dose
  18. What was the tolerance dose in 1934?
    .2 roentgen per day
  19. What was the tolerance dose in 1936?
    .1 roentgen per day
  20. The U.S. Advisory Committee on X-Ray and Radium Protection and National Council on Radiation Protection and Measurements (NCRP) developed:
    the International System of Units (SI Units)
  21. What group developed the International System of Units (SI Units)?
    U.S. Advisory Committee on X-Ray and Radium Protection and National Council on Radiation Protection and Measurements (NCRP)
  22. When was the tolerance dose replaced, and what was it replaced by?
    • the early 1950s
    • maximum permissible dose (MPD)
  23. What is the unit of measurement for maximum permissible dose (MPD)?
    rem (radiation equivalent man)
  24. What determination was made that caused the extinction of the "tolerance level" concept?
    the determination that no amount of radiation was safe
  25. When were dosimeters able to differentiate between various radiation types?
    the 1970s
  26. When and how was the effective dose (EfD) developed?
    • 1991
    • developed by referencing the epidemiologic damage to atomic bomb survivors
  27. What is the SI unit of measurement for the effective dose?
    Sievert (Sv)
  28. What is the traditional unit of measurement for the effective dose?
  29. What is the effective dose based on and what does it take into account?
    • based on the energy deposited in biologic tissue by ionizing radiation
    • takes into account the type or radiation and the sensitivity of the tissues
  30. Though the ICRU encourages the use of SI units, the U.S. still commonly uses the traditional units of:
    • roentgen
    • rem
  31. the internationally accepted unit for measurement of exposure to x-radiation and gamma radiation:
  32. ionization in air:
  33. Roentgen is the photon exposure that produces a total positive or negative ion charge of:
    2.58 x (10)-4 coulooumbs per kilogram of dry air.
  34. Survey meters and calibration chambers use the unit R to measure the _________ of radiation in air.
  35. Previously defined as the dose that is equivalent to any type of ionizing radiation that produces the same biologic effect as 1 rad of x-radiation.
  36. Concerning rem, one rad corresponds to an energy transfer of:
    100 ergs per gram of irradiated object
  37. What unit of measurement is used on your Landauer Reports to measure your clinical exposure to radiation?
  38. What is today's SI unit for absorbed dose?
    Gray (Gy)
  39. What is the traditional unit for absorbed dose?
    the rad (radiation absorbed dose)
  40. What concept relates the energy absorbed in a medium to the energy of radiation it was exposed to while taking into consideration the atomic numbers and density of the medium's ability to absorb energy?
    the Bragg-Gray Theory (1936)
  41. What are the four radiation quantities?
    • Exposure (X)
    • Absorbed Dose (D)
    • Equivalent Dose (EqD)
    • Effective Dose (EfD)
  42. The amount of radiation responsible for the ionization of a well-defined volume of air determined by measuring the number of electron-ion pairs or charged particles in that volume of air:
    Exposure (X)
  43. What can be used to measure Exposure (X) ionization in air:
    the standard or free-air ionization chamber with a controlled temperature, pressure, and humidity
  44. What is the SI equivalent to the traditional unit of roentgen?
    Coulombs per kilogram
  45. the amount of energy per unit mass absorbed by the irradiated object
    absorbed dose (D)
  46. If you lower the radiation energy, does the absorption increase or decrease?
  47. If you increase the atomic number or density of the tissue, does the absorption increase or decrease?
  48. The SI unit of measurement for Absorbed Dose (D) is:
    • Gray (Gy)
    • 1Gy=1J/kg
  49. The traditional unit of measurement for Absorbed Dose (D) is:
    • rad
    • 1 rad = 100 erg/g
  50. Quality factor (Q) list:
    • X-ray photons (Q)=1
    • Beta particles (Q)=1
    • Gamma Particles (Q)=1
    • Thermal neutrons (Q)=5
    • Fast neutrons (Q)=20
    • High-energy ext. protons (Q)=1
    • Low-energy int. protons (Q)=2
    • Alpha particles (Q)=20
    • Multiple charged particles unknown (Q)=20
  51. the amount of energy transferred on average by incident radiation to an object per unit length of track through the object
    Linear Energy Transfer (LET)
  52. Does High-LET have a greater or lesser (Q) than Low-LET
  53. If the energy is higher, does that mean an increase or decrease in LET?
  54. the product of the average absorbed dose in a tissue or organ in the human body
    • Equivalent Dose (EqD)
    • associated with radiation weighting factor (Wr)
  55. The probability of biologic damage is dependent on the _____, _______, and ________ of radiation.
    • dose
    • type
    • energy
  56. As the energy decreases, the conversion factor number increases or decreases?
  57. Equivalent Dose weighting factors:
    • X-ray and gamma ray photons (Wr)=1
    • Neutrons, energy less than 10 keV (Wr)=5
    • 10 keV to 100 keV (Wr)=10
    • Greater than 100 keV to 2 MeV (Wr)=20
    • Greater than 2 MeV to 20 MeV (Wr)=10
    • Greater than 20 MeV (Wr)=5
    • Protons (Wr)=2
    • Alpha particles (Wr)=20
  58. How do you calculate the Equivalent Dose (EqD)?
    EqD = D x Wr

    • D being Dose
    • Wr being Radiation Weighting Factor
  59. It incorporates both the effect of the type of radiation used and the radiosensitivity of the organ or body part irradiated through the utilization of appropriate weighting factors
    Effective Dose (EfD)
  60. How do you calculate Effective Dose (EfD)?
    EfD = D x Wr x Wt

    • D being Dose
    • Wr being Radiation Weighting Factor
    • Wt being Tissue Weighting Factor
  61. Can be used to compare the average amount of radiation received by the entire body from a specific radiologic examination with that from natural background radiation
    Effective Dose
  62. Used to describe radiation exposure of the population or group from low doses of different sources of ionizing radiation
    Collective Effective Dose (ColEfD)
  63. How is Collective Effective Dose determined?
    it is the product of the average effective dose for an individual belonging to the exposed population or group and the number of persons exposed.
  64. How is Collective Effective Dose measured?
    by person-seivert (once called man-rem)
  65. Will ion pairs produced increase or decrease as the intensity of x-ray exposure to a volume of air increases?
  66. Give a decimal or fractional representation of centi, kilo, milli, and mega:
    • centi: 1/100
    • kilo: 1000
    • milli: 1/1000
    • mega: 1,000,000
  67. What is the unit of measurement that represents work done or energy expended when a force of 1 newton acts on an object along a distance of 1 meter?
  68. What is the SI unit for electrical current?
  69. One joule of energy absorbed from any type of ionizing radiation in 1 kg of matter in the irradiated object equals how many Gray?
    1 Gy
  70. Describe how to convert from roentgen to coulomb/kilogram and vice versa
    • roentgen mutiplied by (2.58 x 10-4) = Coulomb/kg
    • coulomb/kg divided by (2.58 x 10-4) = roentgen
  71. Describe how to convert from rad to gray and vice versa
    • rad x .01 = gray
    • gray / .01 = rad
  72. Describe how to convert from rem to sievert and vice versa
    • rem x .01 = sievert
    • sievert / .01 = rem
  73. Describe how to convert from curie to becquerel and vice versa.
    • curie multiplied by (3.7 x 1010) = becquerel
    • becquerel divided by (3.7 x 1010) = curie
Card Set
Unit 3 (Radiation Quantities & Units)
do not rely solely upon these cards. last revised fall2011.