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2010-08-29 14:46:39

radiobiology chapter 8
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  1. what are 2 incidents of modern radiation incidents?
    Three Mile Island and Chernobyl
  2. Define Late effects
    long-term effects such as malignant disease, local tissue damage, life-span shortening, genetic damage, and potential effects to the fetus.
  3. Three Mile Island - what was the exposure and mile radius?
    8 mrem at 10 miles
  4. Three Mile Island - what was the addition of cancer deaths of population and what was the mile range?
    .7 additional deaths at 50 mile radius
  5. What is the suggestion in regards to death and three mile island
    • political backlash against nuclear power will cause more deaths due to the production of power in the traditional ways
    • 100 per year due to mining and transportation
    • 125,000 per year chronic respiratory disease
    • 1 million person-days of aggraved heart and lung symptoms
  6. Why was Chernobyl more of a threat?
    much larger area impacted and much higher exposure levels
  7. statistics of Chernobyl
    • of 444 workers on site
    • 203 suffered acute radiation syndrome
    • 100-200 rem (105 workers) - no deaths
    • 200-400 rem (53 workers) - one died
    • 400-600 rem (23 workers) - 7 died
    • 600-1600 rem (22 workers) - 21 died
  8. Define epidemiology
    • study the distribution and cause of disease in human populations
    • observation only, not experimentations
  9. what is the focus of epidemiology of radiation been on
    cancer induction
  10. what are the limitations of epidemiology?
    • incidence of cancer is compared to expected incidence
    • increase may not be statistically significant
    • not possible to isolate all factors
    • dosimetry problems
  11. define


    example: 1 million people exposed to 1 rad results in 6 more cases than expected, would be an absolute risk of 6
  12. define

    number of excess cases than what would be expected
  13. define

    • used when dose is unknown
    • exposed group is compared to unexposed group
    • ranges from 1-10
  14. What risk types are preferred?
    Absolute Risk and Relative Risk
  15. what is the most radiogentic tumor
  16. what is the type for adults
    acute and chronic myeloid leukemia
  17. what is the type for children
    acute and chronic lymphocytic leukemia
  18. what dx has the shortest latent period of any malignant dx?
    leukemia at 5-7 years
  19. what is the risk period for leukemia
    considered 20 years
  20. what is osteosarcoma?
    bone cancer
  21. what type of cancer was observed in radium dial painters?
    osteosarcoma or bone cancer
  22. what is the half-life of Radium? Where is it deposited?
    1620 years. Bone
  23. Why is Radium bone cancer not compared to diagnostic x-rays?
    Radium emits high LET alpha and beta particles
  24. with osteosarcoma or bone cancer what bones are most affected?
    femur, mandible, and pelvis
  25. lung cancer
    • increased incidence not seen in chest fluoro study
    • increased incidence was seen in miners
    • attributed to radon
    • most miners also smoked which compound problem
    • increase of 6-8 times in non-smokers
    • increase of 20 times in smokers
  26. Thyroid Cancer - where did this turn up the most
    Chernobyl victims
  27. what is the latent period for thyroid cancer
    10-20 years
  28. what is the response curve of thyroid cancer
    • linear, non-threshold
    • even 1 photon will cause damage
  29. women are how many times more likely to develop radiation induced thyroid tumors over males and why
    4 times greater risk - due to hormonal changes
  30. breast cancer

    can radiation induce this type of cancer
  31. at what age do we see no increased risk
    over 40 years of age
  32. why continue with mammography?
    benefits outweigh the risk
  33. list the 9 conclusions
    1 single exposure can elevate incidence of cancer 2. no radiounique cancer 3. almost all cancers increase with irradiation 4. breast, bone marrow, and thyroid especially radio-sensitive (mitotically active) 5. most prominent radiogenic tumor is leukemia 6. solid tumors of latent period of at least 10 years 7. age of exposed individual most important factor 8. increase in cancer incidence varies between organs and cancer types 9. dose-effect curves are assumed to be linear (linear, non-threshold) - as dose doubles incidence doubles. Law of bergonia and tribedaux
  34. what is the largest organ of the body
  35. what is the function of the skin
    to cover, protect from microbes, control body temp, regulate blood flow, and excrete wastes
  36. at what level is radiation induced damage most likely to occur
    basal level or subcutaneous
  37. skin may not regenerate at what exposure levels?
    levels over 1000 rad - collimated local tissue dose not whole body dose
  38. the male system is considered ___________except for the ___________which are ______ __________.
    radio-resistant, testes, moderately radio-sensitive
  39. in the male reproductive system
    at what levels do we see temporary sterility,
    at what levels do we see permanent sterility?
    • 200-250 rad = temp
    • 500-600 rad = perm
  40. in the female reproductive system
    the female system is _______ ________

    and is a function of ___________
    moderately radio-resistant

  41. in females the function of age

    what age group is more radio-resistant?
    at younger ages more resistant

    level changes and goes more sensitive as we grow older
  42. chromosomal damage is considered for which reproductive system

    male or female
    considered for both systems
  43. what part of the eye is not as radio-resistant as the other parts
  44. what is the major outcome of exposure to the eyes
  45. what is the latent period for issues with the eyes
    up to 30 years
  46. what is the threshold level (in rad)
    may be 200 rad but this in not certain
  47. hemopoietic systems consists of what
    blood forming organs (marrow), circulating blood, and lymphoid system
  48. where is this most likely found
    in the blood forming marrow; primarily ribs, ends of long bones, vertebrae, sternum, and skull also includes the flat bones of the pelvis
  49. why is marrow radiosensitive
    blood forming stem cells
  50. why is circulating blood radio-resistant
    because it consits of post mitotic RBC and plateletes
  51. what makes up the lymphatic system
    lymph nodes, thymus, spleen, and some bone marrow
  52. what is the primary purpose of the lymph system
    to produce WBC
  53. what is the sensitivity level of the lymph system
    moderately radiosensitive
  54. which is more senstive to radiation

    blasts or cytes
    blasts are more sensitive since they still have their nucleus

    cytes no longer have a nucleus
  55. cardiovascular system consists of
    blood vessels and heart
  56. cardiovascular system is ______ except for _____ _______. why
    radio-resistant, endothelial cells (lining) may divide excessively leading to blockage.

    small vessles are more radiosenstive than larger vessels (takes less to block)
  57. The heart is
  58. respiratory system consists of
    nose, pharynx, trachea, and lungs
  59. the respiratory system is _____ _____.

    what is the only major long-term radiation effect and what is the dose this is seen at
    moderately radio-resistant

    fibrosis major effect seen after doses over 2500 rad
  60. digestive system consists of
    mouth, esophagus, stomach, small bowel, large bowel, and auxillary organs
  61. digestive system is considered
    moderately radio-sensitive - different portions have different radiosensitivities

    doses of 500 rad can cause atrophy

    doses over 1000 rad can permanently destory villi (motility and absorption)
  63. liver is moderatley radio-sensitive - why
    due to large blood supply
  64. what dx usually results form damage to livers blood supply
    radiation hepatitis
  65. urinary system consists of :


    only long term effects are__ & ___ at what rad level?
    kidneys, ureters, bladder and urethra

    considered - relatively radio-resistant

    • renal failure and atrophy
    • 2500 rad
  66. what is the functional part of the urinary system
    paranchima (meaty portion) see damage quickly

    stroma or vasculature - see damage less quick - supportive
  67. growing bone and cartilage

    what type of cells are radio-resistant?

    why are osteoblasts and chondroblasts moderatley radiosenstive?
    mature cells

    consists of stem cells
  68. at what level do we see a halt in mitosis

    at what level do we see permanent suppression in mitosis
    100 rad see halt in mitosis

    1000+ rad see permanent suppression in mitosis
  69. CNS consists of:

    sensitivity level is:

    level we see damage and the damage is:
    brain and spinal cord


    2000 rad see necrosis and fibrosis due to damage to vascularity
  70. life span shortening

    no data supports that radiation causes life-span shortening - true or false

    life-span shortening effects are due to :

    due to the radiation induced effects such as leukemia

    can not prove that radiation induced cancer
  71. genetic damage

    weakest or strongest area of understanding?

    most data has been gained from experiments on

    experiments with fuit flies - H J Muller's experiments
  72. what was found via H J Mullers fruit fly experiments
    • no increase in quality or types of mutations, only increase in incidence
    • most mutations were recessive
    • no threshold (followed linear, non-threshold)
    • did not matter if dose was fractionalized or one large dose
  73. what dose the dose part mean?
    mutations are single hit and cumulative
  74. cytogenetic damage

    define double dose

    define GSD
    double dose - dose necessary to double the frequencey of genetic mutations

    GSD - genetic significant dose - averages the gonadal exposure over an entire population (exposed and unexposed)

    indicates the genetic effect of exposure on a population
  75. Prenatal Death

    what is the usual response?

    what is the rad level that causes prenatal death (divide it down)
    typically an "all or nothing" response

    • 200 rad causes prenatal death
    • day 1 to 80%
    • day 9 to 30%
    • as fetus ages sensitivity decreases
  76. neonatal death

    what exposure will be primarily at root cause
    after birth

    rare but from exposure in organgenesis
  77. 10 day precaution measures

    28 day rule
    10 day - limit to 1st 10 days after menustration onset - least likely to be pregnant

    28 day - can be preformed up to 28 days after menustration

    all or nothing response