Radbio_11_9 KSW Radiation Protection & Safety(2).txt

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Radbio_11_9 KSW Radiation Protection & Safety(2).txt
2012-12-20 23:40:45
Radiation Protection Safety

Radbio_11_9 KSW Radiation Protection & Safety(2).txt
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  1. Radiation with sufficient energy to separate an electron from its atom is called ______ _______.
    ionizing radiation
  2. Within a RT department there a two major radiation sources. The first  group comprises  ______________(cobalth teletherapy units or linear accelerators) and use xrays,gamma rays, and sometimes electrons.  The second group comprises__________, which uses gamma rays and xrays from sources such as cesium-137, Iridium-192, and Iodine-125.
    • External beam therapy machines
    • brachytherapy sources
  3. ________particles consisit of  2_______ and 2 ______ and are therefor simply helium nuclei. They are emitted from unstable heavy nuclei such as radium or radon during the decay process. They can travel  only short distances (most can be stopped by a sheet of paper), but they produdce intense ionization  and are therefor ______ _______ radiation. They are extremely hazardous if _________ or ________ but less dangerous if exposure is ________.
    • Alpha
    • protons, neutrons
    • high LET
    • ingested  or inhaled

    *alpha particles have to be ingested or inhaled to be dangerous because they are high LET: they travel very short distances and therfor are stopped by the skin(like the sheet of paper)
  4. The only type of ionizing radiation that doesn't originate from the nucleus are _______ which come from  _______.
    • X-rays
    • electron shells
  5. _____particles are electrons emitted by he nucleus and may be either positively charged_____ or negatively charged. _______are not stable and exist for a very short time. Whenever _____particles are emitted, they are acompanied by a ________.Both types of ___ particles have the same rest  mass as an electron and are usually emitted from the nucleus at high velocities.Beta particles and energetic electrons are more penetrating than alpha particles and  pose both an_____and an _______threat.
    • Beta
    • positrons
    • negatrons
    • Beta
    • neutrino
    • beta
    • external
    • internal
  6. Which kind of radiation is made up of two protons and two neutrons?
    alpha radiation
  7. Which kind of radiation can usually be stopped by a sheet of paper?
    alpha radiation
  8. Which kind of radiation is only a hazard if inhaled or ingested?
    alpha radiation

    *like from radon gas
  9. Which kind of radiation is usually emitted from the nucleus at high velocitis and can be either positively or negatively charged?
    Beta(postitrons and negatrons)
  10. Beta particles have a range of ___cm within soft tissue. Metals may be used for shielding, but _________radiation may result. The probability of ________ x ray production is directly proportional to the square of the ______ ______ of the absorber, and inversely proportional to the square of the mass of the incident particle.
    • 2cm
    • bremsstrahlung(braking)
    • bremsstrahlung(braking)
    • atomic number

    *So, bremsstrahlung(braking) radiation more likely with beta particles( reason:inversely portional to the square of the mass of the incident particle-beta particles are smaller so more likely than alpha particles)
  11. Is bremsstrahlung(braking) radiation more likely to occur with alpha or beta particles?
    beta particles
  12. Photons have no _____ or _______.
    • mass
    • charge
  13. _______rays are photons emitted from a nucleus. _____rays are extranuclear and the result of rearrangements of electron shells or ________ radiation.
    Except for their_____, there is no difference between xrays and gamma rays.
    • gamma
    • xrays
    • bremstrahhlung
    • origin
  14. What are the most common types of ionizing radiation used in radiation therapy?
    xrays, gamma rays & electrons
  15. It was not unitl the _____th century that the general public had any exposure to man-made radiation.
    20th Century(1900's)
  16. ____% of radiation exposure of the U.S. populaion comes from  natural background sources.
  17. The main source of natural background radiation ______.
    radon (55%)
  18. Natural background radiation comes from three sources: _______, __________, and __________,
    • Cosmic rays
    • Terrestrial radiation
    • internal deposits of nucleotides in our bodies

  19. Natural background radiation comes from three sources: _______, __________, and __________,
    • Cosmic rays
    • Terrestrial radiation
    • internal deposits of nucleotides in our bodies

  20. ______ _______originate from nuclear reactions in space or from our own sun. Although the earth's atmosphere acts as a protective barrier against much of the initial bombardment, the primary ______  ________ interact with molecules in the atmosphere to create other reactive agents , known as ________  ________.
    • Cosmic rays
    • cosmic rays
    • secondary particles
  21. Secondary particles that are created by cosmic rays interacting with molecules in the atmosphere include:______, _____ and ______which go on to produce energetic electrons, ____, and _______.
    • neutrons
    • protons
    • pions(short-lived subnuclear particles)
    • (energetic electrons)
    • muons(another subatomic particle)
    • photons
  22. Exposure is higher at the ____ and at the ______. Latitude, solar cycles, and other factors may account for a variation of ______% in exposure. The intensity varies even more with increasing _________.
    • polar regions
    • equator
    • 10%
    • altitude

    • *the variation in dose due to latitude is because charged particles incident n the earth are drawn along the magnetic field lines, which are directed towards the poles.
    • *exposure increases with altitude because there is less atmosphere to absorb the rays.
  23. Are people  who live on the Eastern Seaboard or  people who live in the the Rocky Mountains exposed to more radiation?
    People who live in the Rocky Mountains recieve more radiation exposure because of the higher altitude(less atmosphere to block the cosmic rays)
  24. Which make more difference in radiation exposure: latitude or altitude?

    • *Latitude. solar cycles, and other factors may only account
    •  for a 10% variaion in exposure. Intensity varies more with altitude. The dose aprx. doubles with each 2000 meter increase in altitude.
  25. The earth is made up of humdreds of materials, many of which are radioactive because of small amounts of long lived isotopes of uranium, thorium, and radium, among others. This is called _______ radiation.  The largest exposure of this type involves ______which is the 2nd leading cause of lung cancer in the U.S.
    • terrestrial
    • radon(55% of all ionizing radiation exposure in the U.S.)
  26. _______ exposure results from the radioactive materials that are normally present in our bodies. ____ delivers the highest dose to the body.
    • Internal
    • Potassium-40

    *concentrationsof these radioactive material (carbon-14, hydrogen-3, strontium-90 and very small amountss of uranium and thorium) depend on geographic location.
  27. _____ ______ sources include medical x-rays, nuclear medicine procedures, consumer products such as ____ and ________, nuclear reactors, and the fuel cycle and fallout from above-ground nuclear weapons testing. All____ ____ sources make up ____% of the ionizing radiation exposure in the U.S.  _____% of that is medical xrays. etc.
    • Man-made
    • Televisions
    • tobacco products
    • man-made
    • 18%
    • 15%(medical)
  28. Is radon exposure greater in the U.S. or in Kerala region of India?
    Kerala, India(3-4 times more)
  29. Most of the radiation which the general population is exposed comes from _____ _______ radiation, smokers excluded.
    natural background (82%)
  30. ________ is defined as the amount of ionization produced by photons in air per unit mass of air.The traditional unit for _______ is the _____.
    • Exposure
    • Roentgen

    (The SI unit of exposure is the coulomb per kilogram (C/kg). One R =2.58 x 10-4 C/kg.)
  31. Exposure is defined ONLY for ionization produced by photons interacting with_______.

  32. _______  is defined as the energy absorbed per unit mass of  ANY MATERIAL. The traditional unit for ______ is the ______ which is defined as 100 ergs of energy absorbed per gram of the absorbing material The SI unit is the _______.
    • Absorbed dose
    • absorbed dose
    • rad
    • Gray(Gy)

    *(not to be confused with EXPOSURE which only pertains to ineraction with AIR)

    1 gray (Gy) =100 cGy=100 rad (cGy=rad)   1cGy=1rad
  33. For most interactions between photons and soft tissue(most tissue OTHER than BONE), the numeric values for rad and the exposure in R(Roentgen) will be the same to within ______%

    *in other words, because the variable of absorption in air(Roentgen) and tissue(rad-or Gy)
    there is a variation, but it is small(within 10%) For radiation protection purposes, the difference is ignored, but is significant when therapeutic doses to patients are being calculated or measured
  34. __________ takes into account the fact that different types of radiation produce different amounts of radiation in the body. to account for the differencs in biologic effects from different kinds of radiation, each type of radiation is assigned a _____ _____(___).
    • Dose equivalent
    • Quality Factor(QF)

    *For example:Alpha particles and neutrons are high LET and therefor have a greater biologic effect than xrays.(A 20 cGy absorbed dose of alpha particles would be much more damaging in human tissue than a 20 cGy absorbed dose of X-rays0
  35. The traditional unit for exposure is the _____, and the SI unit is __________. The traditional  absorbed dose unit is the _________. The SI unit for absorbed dose is the _____. One  cGy =_______, or 100 rads = _______. The traditional unit for dose equivalent is the ______, and the SI unit is the_______. 100 rems= 1______.
    The traditional unit for activity(disentegration) is the_____  and  the SI unit is the _______.1 curie (Ci) = 3.7 × 10v10 Bq
    • Roentgen(R)in airC/kg
    • Rad, Gray(Gy)  1 cGy= 1 rad or 100 rads= 1 Gy
    • Rem, Sievert(Sv) 1 Sv= 100 rems
    • Curie(Ci), Becquerel (Bq) 1 curie= 3.7x10v10 Bq

  36. For photons and most electrons the quality factor is ______.

    *to come up with equivalent doses -mulitply the dose by the quality factor for that type of radiation.
  37. Quality factors for Various Ionizing Radiations:
    Xrays and gamma rays(photons): ____
    Beta particles, positrons, muons______
    High-energy external protons______
    Protons other than recoil protons in energy >MeV_____
    Thermal Neutrons_______
    Fast Neutrons______
    Alpha Particles_____
    Fission fragments, other heavy nuclei_____
    • Quality factors for Various Ionizing Radiations:
    • Xrays and gamma rays(photons): _1___
    • Beta particles, positrons, muons___1___
    • High-energy external protons___1___
    • Protons other than recoil protons in energy >2 MeV__2__
    • Thermal Neutrons__5_____
    • Fast Neutrons___20___
    • Alpha Particles__20___
    • Fission fragments, other heavy nuclei__20___
  38. Quality factor for Alpha particles:
  39. Quality factor for xrays and gamma rays(photons)?
  40. Quality factor for beta particles?
  41. Quality factor for positrons?
  42. Quality factor for muons?
  43. Quality factor for high energy protons?
  44. Quality factor for protons, other than recoil protons and energy >2MeV?
  45. Quality factor for thermal neutrons?
  46. Quality factor for fast neutrons?
  47. Quality factor for alpha particles?
  48. Quality factor for fission fragments, other heavy nuclei?
  49. Which types of radiation have a quality factor of 20?
    • Alpha particles,
    • fast neutrons
    • fission fragments and other heavy nuclei.
  50. Which types of radiation have a quality factor of 1?
    • Photons(xrays, gamma rays)
    • Beta particles, positrons, muons
    • high energy external protons
  51. __________takes into account the effect of irradiation of only part of the body or nonuniform irradiation of the body.
    Effective dose equivalent

    • *NOT TO BE CONFUSED WITH QUALITY FACTORS:QF's are numbers that when multiplied(factors) by the dose,take into account the different strengths of different kinds of radiation. QF's make it possible to compare the biologic effect of dosages of different kinds of radiation.
    • EFFECTIVE DOSE EQUIVALENT: different organs are given different weighting factors depending oh theeir sensitivity. The dose to each significant organ is multiplied its weighting factor, and then a sum is taken that provides a meausre of risk to the individual that a uniform exposure to the entire body of the same value would have.
  52. 1 Ci =________mCi, 1mCi = ______µCi
    • 1000
    • 1000
  53. A _____ is an instrument that has a chamber filled with gas that is ionized in part or whole when radiation is present.
    Either the total quantity of the ____ ______ is measured or  the rate at which charge is _______ is ________. Two kinds of ________ may be found in a radiation therapy department. The ________ and the ________.
    • gas filled detector
    • electrical charge
    • produced
    • measured
    • gas filled detector
    • ionization chamber
    • Geiger-Muller detector
  54. Describe a gas- filled detector:
    The ionization chamber is the simplest and consists of two electrodes within a gas-filled chamber, an applied voltage across the electrodes, and electronics and a meter to amplify and measure the electrical signal.
  55. Which kind of radiation detector, because of it sensitivity, is better suited for finding contaminaion and oher low levels of radiation?
    • The Geiger-Muller(G-M) detector.
  56. When______ _____ are properly calibrated, their accuracy approaches _______, which makes them suitable for measurement of the radiation output of  therapy equipment.;
    ionization chambers, 2%

  57. Beause ionization chambers are not very _____, they are not suitable for detection of low levels of radiation or radiation contamination.

    *GM detectors are best for finding contamination and other low levels of radiation
  58. Because of their small size ,_________ are widely used to measure radiation in a number of applications. ________materials(LiF among others) give off light when heated. At a later time the crystal is heated to 100-200 degrees and the amount of light it given off is a measure of the dose recieved by the crystal.TLDs are used in mailed intercomparison of therapy unit calibration, in ring badges used for personnel monitoring, and for measurements of enviormental levels of radiation.
    • Thermoluminescent dosimeters
    • thermoluminescent

  59. The atomic number of ___ is close to that of tissue so ________mimics tissue closely and is therefore useful as a patient of phantom dosimeter.
    • LiF
    • LiF
    • LiF is a crystalline powder that comes in capsules for this application
  60. After development, xray film exposed to radiation turns _____. The amount of _______ is called _______and is related to the amount of radiation received by film. The actual relationship is NOT ________ and depends on the type of film, the type and energy of the radiation, and the details of the processing of the film. However, once calibrated, film is a convenient and inexpensive way to provide imformation about doses received by individuals working in or visiting areas where radiation may be present.
    • BLACK
    • blackness
    • optical density =(the amount of BLACKNESS)
    • linear
  61. A typical ______has a slot in which film(in it's protective paper cover) may be placed in several thin metal ______ that surround portions of the film. The _____ allow discrimination between different types  and energies of radiation. ________ energy radiation will not penetrate any of  the _____ but can reach the film in the area where no _____ are present. ________ energy radiation will penetrate the _____ and the _____ areas but will not get through the lead ______. High -energy radiation penetrates all areas.
    • film badge
    • filters
    • filters
    • Low
    • filters
    • filters
    • Medium
    • no filter (and the) tin filter
    • (lead) filter
    • *tin blocks low energy radiation only
    • *lead blocks medium and low energy radiation
    • High energy is not blocked by tin or lead
  62. The primary job of _________ agencies is to analyze the existing data related to radiation exposure and to assess the risks associated with these exposures. These agencies can then develop recommendations for dose limits.
  63. Some of the advisory agencies include:
    • (NCRP) National Council on Radiation Protection & Measurement
    • (ICRP) International  Commission on Radiation Protection
    • (UNSCEAR) United Nations Scientific Committee on the Effect of Atomic Radiation
    • (NAS-BEIR) National Academy of Science on the Biological Effects of Ionizing Radiation
    • *yikes!!
  64. The primary job of ______ agencies is to liscense users of radioactive materials, and radioactive producing equipment, inspect such users, and enforce the appropriate laws.
  65. Some of the regulatory agencies include:
    • *NRC- The Nuclear Regulatory Committee:
    • it oversees the use of isotopes produced in nuclear reactors. These isotopes are commonly used in nuclear medicine departments, in laboratories, as sources for teletherapy(EXTERNAL BEAM RADIATION!), and brachytherapy.
    • DOT-Department of Transportation-transportation of radioactive materials
    • FDA-Food and Drug Administration-the use of machines that produce ionizing radiation(xray units, linacs) also State Agencies
    • EPA-Environmental Protection Agency
    • OSHA-Occupational  Safety  & Health Administration
  66. regulatory or advisory agency: EPA?
  67. Is OSHA a regulatory or advisory agency, and what does it stand for?
    • regulatory
    • Occupational Safety & Health Administration
  68. Is the NRC a regulatory or advisory agency, and what does NRC stand for?
    • regulatory
    • Nuclear Regulatory Committee

    *notice the word Regulatory in the name is a dead giveaway to the type of agency it is
  69. Is the DOT a regulatory or advisory agency, and what does DOT stand for?
    • regulatory(regulates transportaion of radioactive materials)
    • Department of Transportation
  70. Is the NCRP a regulatory or advisory agency, and what does NCRP stand for?
    • advisory
    • National Council on Radiation Protection & Measurement
  71. Is the ICRP a regulatory or advisory agency, and what does ICRP stand for?
    • advisory
    • International Commision on Radiation Protection
  72. Is UNSCEAR a regulatory or advisory agency, and what does UNSCEAR stand for?
    • advisory
    • United Nations Scientific Committee of Atomic Radiation
  73. Is NAS-BEIR regulatory or advisory agency, and what does NAS-BEIR stand for?
    • advisory
    • National Academy of Science on the Biological Efffects of Ionizing Radiation
  74. Is the FDA a regulatory or advisory agency?
    • regulatory (regulates xray machines, linacs)
    • Food and Drug Administration
  75. Is the DOT a regulatory or advisory agency, and what does DOT stand for?
    • regulatory
    • Department of Transportation(regulates transportation of radioactive materials)
  76. Which agency regulates the the transportation of radioactive materials?
    Department of Transportation(DOT)
  77. Which agency regulates the use of machines that produce radiation such as xray units and linacs?
    Food and Drug Administration(FDA)
  78. Which agency oversees the use of isotopes produced in nuclear reactors commonly used in nuclear medicine departments, in laboratories, and as sources for teletherapy(eternal beam radiation) and brachiatherapy.
    Nuclear Regulatory Commission(NRC)
  79. We have far greater knowledge of the effects of ___doses of radiation than ____ doses.
    high, low

    *This is becuse much of the knowledge comes from study of victims of Hiroshima, Cheronobyl, Nagasaki, as well as children treated with radiation for enlarged thymuses
  80. In sufficiently high doses, radiation can be ______.
    A single whole-body exposure of approximately_____Gy is lethal for 50% of the exposed population in 30 days. In other words, the LD50/30 is ______.
    • lethal
    • 4.5
    • LD 50/30= 4.5 Gy (450 rads)
  81. LD50/ 30 is _____Gy.  LD50/30 is considered a _____ dose.
    • 4.5 Gy
    • lethal
  82. Effects related to radiation fall into two general classifications:________ and non_________.
    • stochastic
    • nonstochastic
  83. _________effects are those for which a threshold exists and for which severity of the effect increases with dose. Examples of ______ effects are  erythema, _____, _______, and infertility.
    • Nonstochastic
    • cataracts
    • epilation(hair loss)

    • *remember: NONstochastic=yes threshold(it's kind of counter intuitive unless you remember that
    • stochastic effects DO NOT have a threshold and the severity of effect is NOT a function of the dose
  84. ______ effects are those that have NO THRESHOLD and for which the probability of occurance is a function of the dose. In this case the severity of he effect is NOT A FUNCTION OF THE DOSE. Examples of _____ effects include_______ induction, _______,and _________.
    • Stochastic
    • cancer induction
    • genetic effects
    • embryologic and teratogenic effects.
  85. Because of a lack of threshold dose, _______ effects are of more concern at ____ levels of radiation.
    • stochastic
    • low

    *Because we don't know how much radiation it takes to induce cancer(because their is no threshold), for example, any amount is a concern. Survivors of Nagasaki are the primary source for estimating cancer risks with ionizing radiation: a linear-quadratic response for leukemia and a a linear response for solid tumors.
  86. The overall risk of exposure to radiation is approximately ____ in ______ persons per rem.
    7 in 10,0000  persons per rem
  87. In terms of embryologic and teratogenic effects, the NCRP assigned a total overal risk estimate of _____ in _____ per Gy
    4 in 10 per Gy