RAD BIO CH 4 10/19 CH

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RAD BIO CH 4 10/19 CH
2012-10-18 15:05:09

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  1. The total body response to radiation is presented in terms of 3 ______ ______
    Radiation Syndromes
  2. Characteristics of each syndrome are dependent on the ______ received and exposure conditions.
  3. What are the 3 specific exposure conditions that apply in dealing with radiation syndromes?
    • 1. exposure must be acute (minutes)
    • 2. total body or nearly total body exposure must occur
    • 3. exposure must be from an external penetrating source rather than ingested, inhaled, or implanted radioactive sources.
  4. What are the 3 syndromes
    • Hematopoetic
    • Gastrointestinal
    • Cerebrovascular
  5. What is the hemopoetic syndrome
    blood syndrome that has a deficiency of WBCs, lymphocytes and platelets.
  6. What is induced by a total body dose of 100-1000 cGy?
    Hematopoetic Syndrome
  7. In hematopoetic syndrome LD 50/60 for humans is estimated to be between_____ and ______ by varies with ____, _____, and _______
    • 350-450 cGy
    • age, health, and gender
  8. Who is more resistant to get the hematopoetic syndrome?
    • females and the middle aged person
    • males and very young and old are more sensitive
  9. What is the depression of all blood cell counts
  10. Note for hematopoetic syndrome
    • most patients receiving less than 300cGY will survive and eventually recover over 3-6 month period
    • After 300-500 cGy death may occur in 4-6 weeks
    • After 500-1000 cGy death is likely within 2 weeks.
    • No record exists of human survival when the total body dose exceeds 1000 cGy.
  11. Which syndrome is induced if the total body dose is between 1000 and 10,000 cGy?
    Gastrointestinal Syndrome
  12. Which syndrome can also be induced at a dose as low as 600 cGy and overlaps with the cerbrovascular syndrome at doses of 5000 cGy or more?
  13. What is the mean survival time for the gastrointestinal syndrome?
    3-10 days or up to 2 weeks with medical support
  14. How does the gastrointestinal syndrome occur?
    as a result of damage to the gastrointestinal tract and bone marrow.
  15. What is the most radiosensitive portion of the digestive system?
    small intestines
  16. After exposure doses of _______, severe depopulation of crypt cells leads to partial or complete denudation (wearing away) of the villi lining the lumen of the small intestine.
    1000 cGy
  17. This syndrome was formerly known as the _____ _____ _____ _______and occurs exclusively after doses of 10,000 cGy or more.
    • central nervous system syndrome
    • Cerebrovascular syndrome
  18. Which syndrome can overlap the gastrointestinal syndrome because it can be induced by a dose as low as 5000 cGy?
    Cerebrovascular Syndrome
  19. How fast can deat occur after the cerbrovascular syndrome doses at over 10,000 cGy?
    several days or less
  20. what can damage the developing embryo and fetus in utero?
  21. how is radiation damage manifested when given in utero?
    as lethal effects, congenital abnormalities present at birth or late effects observed years later.
  22. How can the below effects be produced?
    lethal effects, congenital abnormalities present at birth or late effects observed years later.
    • 1. irradiation of the sperm or ovum before fertilization, thus resulting in inherited effects
    • 2. exposure of the fetus to radiation , thus resulting in congenital defects.
  23. What are the newly formed balls of cells known as?
  24. At what stage is it considered an embryo?
    10 days to 6 weeks
  25. At the end of the 6th week of pregnancy, what is it called?
  26. Unlike the adult the _____ _____ _____ is responsive to radiation and can be damaged at relatively low doses.
    fetal nervous system.
  27. Hematopoetic  Syndrome dose range is
    100-1000 cGy
  28. Hematopoetic  Syndrome recovery time is
    dose dependent- 3 weeks to 6 months; some people do not survive
  29. Hematopoetic  Syndrome time of death?
    3 weeks to 2 months
  30. Hematopoetic  Syndrome organ and system damaged?
    Bone marrow
  31. Hematopoetic  Syndrome signs and symptoms
    • Decreased # of stem cells in bone marrow
    • increased amt of fat in bone marrow
    • pancytopenia (depression of all blood counts)
    • anemia
    • hemorrhage
    • infection
  32. Gastrointestinal Syndrome dose range
    1000-5000 cGy
  33. Gastrointestinal Syndrome time of death
    3-10 days
  34. Gastrointestinal Syndrome organ and system damage
    small intestine
  35. Gastrointestinal Syndrome signs and symptoms
    • denudation (wearing down) of villi in small intestine
    • neutropenia
    • infection
    • bone marrow depression
    • electrolyte imbalance
    • watery diarrhea
  36. Gastrointestinal Syndrome recovery time
  37. Cerebrovascular Syndrome dose range
    > 5000 cGy
  38. Cerebrovascular Syndrome time of death
    <3 days
  39. Cerebrovascular Syndrome organ and system damaged
  40. Cerebrovascular Syndrome signs and symptoms
    • Vasculitis
    • edema
    • meningitis
  41. Cerebrovascular Syndrome recovery time
  42. What should not exceed .5 rem (5 mSv) with monthly exposure not exceeding .05 rem )0.5 mSv) ?
    The maximum permissible dose to the fetus during the entire gestational period from occupational exposure of the mother
  43. The _____ _______ dose to the fetus during the entire gestational period from occupational exposure of the mother should not exceed .5 rem (5 mSv) with monthly exposure not exceeding .05 rem )0.5 mSv) ?
    maximum permissible
  44. what are the most radiosensitive forms of animals and humans?
    embryo and the fetus
  45. in regard to fetal effects of radiation, the principal factors of importance are......
    the dose and the stage of gestation at which it was delivered
  46. Because the latent period for an effect from radiation is inversely proportional to radiation does, the biological response to low dose is not observable for extended periods of time ranging from years to generations. These effects are known as late effects and are termed ____ _____ if body cells are involved and ____ _____ if reproductive (germ) cells are involved
    • somatic effects
    • genetic effects
  47. What is the time interval between irradiation and the appearance of a malignancy?
    latent period
  48. What is the most important late somatic effect induced by radiation?
  49. Radiation is classified as a
    carcinogen or cancer-causing agent
  50. What is considered to be an all or nothing event?
  51. Any dose no matter how low, has some potential of inducing _____
  52. What is a non threshold even with the probability of an effect increasing as the dose increases?
    cancer induction
  53. Carcinogenesis is an example of a ____ _____ in which every dose carries some magnitude of risk
    stochastic effect
  54. The latent period for leukemia induction by radiation is usually ____ to _____ _____ with the peak incidence approx____ to ____ _____ after exposure
    • 4-7 years
    • 7-10 years
  55. Radiation induced solid tumors have a latent period ranging from
    20-30 years or longer
  56. When and where was the 1st radiation induced skin cancer?
    1902 on the hand of a radiologist
  57. what have been the most frequently observed skin cancers following radiation exposure?
    squamous cell and basal cell carcinomas
  58. when the young female watch dial painters licked their brushes that had radium paint on the tip to paint the clock faces, what did they develop in 1915-1930
    osteosarcoma or bone cancer
  59. What is the naturally occurring deposits of radioactive materials in the rocks of the earth and decay thru a long series of steps until they reach a stable isotope of lead?
    Radon gas
  60. The dose range from 1200-6000 cGy was a popular treatment for what and had a 100 fold increase in thyroid cancer
    Irradiation of the enlarged thymuses in children before the 1930s
  61. Ionizing radiation is known as a
  62. Note
    somatic late effects can occur in an irradiated individual, and exposure of reproductive (germ) cells in that individual may affect future generations.
  63. The # of spontaneous mutations that occur in each generation of an organism is
    mutation frequency
  64. If the mutation frequency in a generation is doubled by exposure to radiation, the radiation dose is known as
    doubling dose
  65. What is the TD 5/5 for bladder
    6000 cGy 
  66. What is the TD 5/5 for the rectum
    6000 cGy
  67. What is the TD 5/5 for the Lens
    500 cGy
  68. What is the TD 5/5 for the Fetus 
    200 cGy 
  69. What is the TD 5/5 for the heart
    4500 cGy 
  70. What is the TD 5/5 for the Intestine
    4500 cGy
  71. What is the TD 5/5 for the kidney
    1500 cGy 
  72. What is the TD 5/5 for the Liver
    2500 cGy
  73. What is the TD 5/5 for the lung
    3000 cGy
  74. What is the TD 5/5 for the spinal cord
    4500 cGy
  75. What is TD 5/5
    The tissue dose associated eith a 5% injury rate within 5 years
  76. what is TD 50/5
    tissue dose associated eith a 50% injury rate within 5 years
  77. what is TD 5/5 for the brain
    5000-6000 cGy
  78. What is the TD5/5 for the esophagus
    6000 cGy
  79. What is the goal of Radiation therapy
    To eradicate the tumor all the while not destroying normal tissue
  80. ___ ____ can be induced in tumor AND in normal tissues
    biologic damage
  81. The tolerance dose of the normal tissue limits the ____ that can be administered to the tumor
  82. What is the functional cells of an organ (mutant cells)
  83. What are connective tissue cells called
  84. Describe cells belonging to group 1 of parenchymal
    • viable
    • actively mitotic
    • responsible for tumor growth
  85. the % of group 1 cells in a tumor varies from ___ to ____ and is termed ___ ____
    • 30-50%
    • growth fraction
  86. The ____ _____ typically decreases as the size (volume) of the tumor increases
    growth fraction
  87. describe cells belonging to group 2 of parenchymal
    • viable
    • not dividing
    • basically in the G0 phase
  88. Which cells have retained the ability to re enter the cell cycle and divide if properly stimulated?
    G0 phase or group 2
  89. Which group is not viable
    3 and 4
  90. The rate at which tumors grow depends on 3 major factors
    • the division rate of proliferating parenchymal cells
    • the % of these cells in the tumor
    • the degree of cell loss from the tumor
  91. What is  characteristically unorganized compared with that of normal cells
    tumor growth
  92. During the early stages, tumors begin to outgrow their_____ _____
    vascular supply
  93. Differing levels of O2 availability is
    oxygen tension PO2
  94. Tumors located more than 200 um from the nearset blood vessels (capillaries) are ____ and unable to proliferate
  95. What do anoxic cells that have died form?
    necrotic area
  96. Tumor cells closest to blood vessels are well oxygenated and called _____ and are actively dividing and compose the GF of the tumor
    oxic cells
  97. Gradually decreased O2 tensions are
    hypoxic cells
  98. 15% or more of the tumor cell population may be ____ and this is known as the ___ ____ of the tumor
    • hypoxic
    • hypoxic fraction
  99. The vasculature network that forms in each growing tumor with factors such as division rate, GF, cell loss, ultimately gives rise to ___,____,and ____ cell populations in the tumor.
    • anoxic
    • hypoxic
    • oxic
  100. What is the #1 radiosensitizer
  101. The biologic effects on tissue from fractionated radiation therapy depend on the
    • 4 Rs
    • Repopulation
    • Redistribution
    • Repair
    • Reoxygenation
  102. What are the most radiosensitive phases
    G2 and M
  103. What results in a redistribution of surviving cells after radiation
    Partial Synchronization
  104. When you irradiate a cell population that is in various phases, typically results in death of cells in G2 and M and survival to cells in S, this process is known as
    partial synchronization
  105. What has occurred within hours of radiation exposure in normal and tumor cells in vitro?
    Repairs of sublethal damage
  106. What takes advantage of repair processes in normal tissues that are active between radiation fractions?
    Fractionated radiation treatment
  107. Repair of sublethal damage is ____ dependent
  108. Because a proportion of tumor cells are thought to be ____, tumors in general are presumed to be incapeable of repairing sublethal radiation damage as efficiently as normal tissues
  109. Which R only applys to tumors?
  110. What is the process by which hypoxic cells gain access to O2 and become radiosensitive between radiation fractions?
  111. what decreases during fractionation of xrays and gamma rays
    • OER
    • O2 enhancement ratio
  112. what 5 methods have been used with varying degrees of success of improved tumor response
    • radiosensitizers
    • radioprotectors
    • high LET radiations
    • chemotherapy agents
    • hyperthermia (heat)
  113. what related the treatment schedule in terms of total dose and time with clinical outcome including early and late effects and tumor cure?
    Isoeffect curves
  114. The use of ___ ____ led to treatment schedules fro fractionate XRT that gave a high probability of tumor control without exceeding the tolerance of normal tissue
    Isoeffect curves
  115. What has reduced radiation toxicity to surrounding tissues altering the ratio of normal tissue dose to tumor dose?
    • IMRT
    • intensity modulated radiation therapy