RAD-139 MIDTERM

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anatomy12
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266020
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RAD-139 MIDTERM
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2014-05-06 15:23:55
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xray
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  1. what is ionizing radiation
    ionization removes electrons from the atoms of composing the molecular structures
  2. what is diagnostic efficacy
    the degree to which the diagnostic study accurately reveals the presence or absence of a disease
  3. ALARA:
    • as low as reasonably achievable
    • the use of smallest amt of radiation while producing the most optimal image
  4. what is ORP
    • optimization for radiation protection and is synonymous with ALARA
    • it is to keep radiation exposure and consequent dose to the lowest possible level
  5. what are the cardinal rules for radiation protection
    time distance shielding
  6. describe ways to educate the patient about procedures
    • make the patient aware of the procedure
    • what is expected of them in the procedure through appropriate communication and
  7. what are the advantages of BERT
    what does it not imply
    • does not imply a radiation risk; it is simply a means for comparison
    • it emphasizes that radiation is an innate part of our environment
    • it is an easy way for the patient to comprehend
  8. what is bert
    background equivalent radiation time is the comparison of radiation received to a patient to that of natural radiation received over a period of time on the earth
  9. what is the mrem and BERT of a chest xray
    • bert = 10 days
    • mrem =10
  10. what is the trace program
    what does it stand for
    tools for awareness and community education is a tool that creates a better awareness of radiation doses to reduce patient dose
  11. What is standardized dose reporting
    is keeping a record of a patients dosage history from radiation of different procedures (modalities) such as ct scan fluoro interventional radiation
  12. Describe different radiations along the electromagnetic spectrum (list the radiation in both parts)
    • ionizing radiation:
    • xrays
    • gamma rays
    • high energy ultraviolet rays

    • nonionizing radiation:
    • low energy ultra violet
    • visible light
    • infrared rays
    • microwaves
    • radiowaves
  13. describe particulate radiation (contains 4 types)
    subatomic particles that are ejected from atoms at a high speed

    • alpha particles
    • beta particles
    • neutrons
    • protons
  14. describe alpha particles
    • emitted from the nuclei of very heavy elements such as uranium
    • contains 2 protons and 2 neutrons
    • lose energy quickly can travel short distance
  15. when are alpha particles considered harful and harmless
    • harmless = as an external source a piece of paper can act as a shield
    • hamrful = from an internal source if emitted from a radioisotope deposited in the body
  16. beta particles are how many times lighter than alpha
    what is their mass and charge
    what are they capable of doing
    • 8000x
    • small mass and neg charge
    • penetrating biological matter to a much greater depth than alpha particles w/ less ionizations also
  17. describe protons and neutrons
    • protons pos charged components of an atom
    • neutrons are electrically neutral components of an atom
  18. equivalent dose is expressed in what unit
    Rad x rem =
    • REM or Sv
    • QF
  19. what is equivalent dose or EqD
    a quantity that attempts to take into account the variation in biological harm produced by diff types of radiation
  20. describe the diff sources from nat radiation and bg radiation
    • terrestrial = radon largest contributor of natural radiation
    • cosmic (radiation exposure when on a plane) = extraterrestrial intensity varies with altitude; atmosphere and magnetic field act as a shield
  21. The CURRENT annual ionizing radiation exposure from both manmade and natural sources to the population of the united states is ______ mrem
    How much if it was just natural radiation?
    • 625 or 6.25 mSv
    • 2.95 mSv 295 mrem
  22. how much radiation is someone exposed to per hour of air travel on a typical commercial airliner
    0.005-0.01 mSv/hr
  23. the NCRP report No 93 states that medical use (nuclear Medicine.CT Fluoro interventional and conventional radiography) now makes up ____ % of total collective dose for the population of the united states
    48%
  24. the NCRP report 93 from 2006 states that the main cause associated with the new annual background radiation dose is the increased in what studies
    CT studies
  25. what are ESE (entrance skin exposures) for chest abdomen lumbar spine and extremities
    • chest pa - 10mR
    • abdomen ap - 220 mR
    • extremity - 5mR
    • lumbar - 250mR
  26. in the electromagnetic spectrum higher frequencies are associated with what wavelengths and energies:
    shorter wavelengths and higher energies
  27. if a person spends 10 hours flying aboard a commercial aircraft during a period of normal sunspot activity the dose of radiaition received is equivalent to _____
    a chest xray
  28. what is the effective dose
    takes into account dose for all types of ionizing radiation to organs tissues and the overall harm (weighing factor) for developing radiation induced cancer or genetic damage
  29. what is kvp and mAs
    • kvp the highest (strongest) energy level of photons in the beam
    • mAs product of electron tube current and the amt of time in seconds that the xray tube is activated
  30. what is the production of primary x radiation
    produces brems and characteristic photons
  31. List the two functions of grids
    Grids remove scatter and improve contrast
  32. when using a grid what technical factor must we increase
    mAs
  33. what is the minimum kvp for a characteristic interaction to happen
    above 70kvp
  34. what is the average energy of an xray beam
    30-40 percent or 1/3 of the primary beam
  35. describe the energy of photons in an xray beam
    it consists of xray photons of various energies are produced but the strongest is the one with w.e. kvp selected
  36. what happens when xrays interact with human tissue (2things)
    they may interact with the atoms of the biological material in the patient or pass through without interaction (penetration)
  37. what is another word for attenuation and what does it mean
    • attenuation = absorption
    • attenuation is the reduction in the number of primary photons in the beam through absorption and scatter
  38. primary photons:(list 2)
    • brems(happens more often) and characteristics
    • xrays that leave the tube
  39. what are exit photons
    (list 2 examples)
    • radiation that leaves the patients body
    • (scatter or penetrating photons)
  40. what are attentuated photons
    scatter or absorption
  41. what is coherent scattering
    an interaction that occurs between low energy xray photons and matter
  42. what are the two types of coherent scatter
    and describe each
    • rayleigh
    • thompson
    • rayleigh scatter - involves all electrons in the interaction
    • thompson - involves a single electron in the interaction
  43. what is compton scattering
    occurs when an incident xray photon interacts with a loosely bound outer shell electron removes the electron from its shell and then proceeds in a different direction as a scattered photon
  44. what is small angle scatter radiation affects what
    • it is scatter created from compton scattering
    • it affects IR and image
  45. what is responsible for most of the scatter produced during an xray radiologic examination
    compton scattering
  46. what is photoelectric absorption
    what is a by product of characteristic radiation
    secondary radiation is aka
    • happens when an xray photon interacts with an inner shell electron
    • secondary radiation
    • characteristic radiation
  47. what two things determine the probability of a photoelectric absorption
    in regards to technical factors how can we increase the photoelectric absorption
    • the energy of the incident photon
    • and a high atomic number of the irradiated anatomy
    • lower kvp or energy of incident photon decreases
  48. what are the differences of attenuation in bone and soft tissue
    what other risk increases as absorption increases
    • soft tissue is more penetrable than bone
    • bone absorbs majority of the photons because of the high atomic number
    • biological damage
  49. the less attenuation(absorption) of a given structure the ______ the radiographic density
    greater = more penetration = darker image
  50. the more attenuation (absorption) of a given structure the ____ radiographic density
    lesser= less penetration = lighter image
  51. what contributes to radiographic fog
    it is created by additional unwanted sctter produced by the pt's body from compton scattering
  52. a positive contrast medium has what kind of atomic number
    negative contrast medium has what kind of atomic number
    • high atomic number
    • low atomic number
  53. what affects the probability of photon interaction with matter
    when xrays interact with matter electromagnetic energy is transferred from the xrays to the atoms of the patients biologic material (absorption) and the amt of energy absorbed per unit mass is the absrobed dose
  54. what is pair production
    happens when the energy of xray photons is converted to matter in the form of a positron and a negatron (2 electrons)

    the xray photon comes in and interacts with the nucleus, in the process it ejects two new particles at the same time (positron and negatron)
  55. what is photodisintegration
    an incoming high energy photon that collides with the nucleus of the atom and absorbs all the photons energy
  56. what diagnostic field uses annihalation (destroys nucleus) reaction
    PET scan positron emission tomography
  57. at what energy does photodisintegration
    10MeV
  58. Which of the following is not a type of interaction between xradiation and biologic matter (compton brems pair production or photoelecetric absorption)
    brems
  59. In photoelectric absorption, the kinetic energy of the incoming xray photon must be ____ to be able to dislodge an inner shell electron from its orbit
    the same as or greater than the energy that binds the electron in its orbit
  60. the probablility of occurrence of photoelectric absorption ______ as the energy of the incident photon decreases and the atomic number of the irradiated atoms _____
    Increases markedly , increases
  61. xray photons that penetrate through the patient and strike the image receptor are called
    exit radiation
  62. what is considered as attenuation (2 things)
    Which of the different interactions refers to the radiation that occurs when an electron drops down from an outer orbit to fill a vacancy in an inner orbit of the parent atom
    • scatter photons
    • absorbed photons

    characteristic radiation
  63. which two interactions between xradiation and matter may result in the production of small angle scatter
    coherent scattering and compton scattering
  64. according to your text what is the term for the number of characteristic xrays emitter per inner shell vacancy during photoelectric absorption
    fluorescent yield
  65. as kvp increases the total number photons that are transmitted without interaction (penetration) increases 
    T or F
    t
  66. the xray photon energy required to initiate pair production is
    1.022 meV
  67. who invented xradiation and in what year
    wilhelm roentgen in 1895
  68. who was the first american fatality
    clarence madison dally
  69. somatic damage:
    what is SED and when was it used
    biological damage to the body of the exposed individual caused by ionizing radiation

    skin erythema dose is the unit in use for measuring the quantity of radiation exposure that caused redness over an area of skin after irradiation from 1900-1930
  70. differentiate between short term (non stochastic) and long term somatic effects (stochastic)
    • short term damage that appears within minutes hours days or weeks
    • long term effects damage that appears after many months or years after exposure and possibility of genetic risks
  71. who are the NCRP
    radiation standards organization
  72. what traditional quantities and units are used today
    • roentgen
    • rem
    • rad
  73. Define roentgen
    what does rem stand for
    fluorscopic entrance exposure rates are measured in _____
    • unit for measurement of exposure to x and gamma radiation in air
    • radiation equivalent man
    • roentgen
  74. define rad:
    • is the unit for absorbed dose (RAD or GY)
    • the amt of energy per unit mass absorbed by an irradiated object
  75. define rem
    it measures dose equivalent or equivalent dose
  76. what SI units are used today
    how do you convert from traditional to SI
    mill to no milli
    no milli to milli
    • Gy Sv and coulombs per kilo
    • Rad - Gy (divide by 100)
    • REM - Sv (divide by 100)

    • divide by 1000
    • mult. by 1000
  77. how is fluorscopic entrance dose measured
    in roentgen per minute
  78. define exposure
    absorbed dose
    effective dose
    • ionizing radiation in air
    • the amt of energy per unit mass absorbed by an irradiated object

    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
  79. equivalent dose:
    the product of the average absorbed dose in a tissue or organ and its associated radiation weighing factor (Wr)(alpha or beta)
  80. 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
  81. what is Wt and what is Wr
    which dose involves the tissue weighting factor
    • wt = tissue weight factor that describes
    • relative risk associated with irradiation of diff body tissues
    • wr =radiation weight factor of various types of ionizing radiation
    • effective dose
  82. which dose involves the radiation weighting factor
    which does deals with the amount of radiation absorbed in an irradiated object per unit mass and is measured in rad or gy
    • equivalent dose
    • absorbed dose
  83. what is TEDE
    total effective dose equivalent is a radiation dosimetry quantity that was defined by the NRC to monitor and control human exposure to ionizing radiation
  84. who invented the xray and in what year
    wilhelm roentgen in 1895

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