Chapter 4 radiation Biology

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Chapter 4 radiation Biology
2014-03-03 12:08:59
Chapter4 radbio

Chapter 4 Rad Bio
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  1. TD 5/5 indicates the dose required to cause a 5% chance of injury to people irradiated within _________ following exposure
    5 years
  2. LD 50/30 indicates the dose likely to cause death in 50% of the population within ________ following exposure
    30 days
  3. The TD5/5 for the whole kidney using standard fractionation is approximately: ___________
    23 Gy
  4. The TD 5/5 for the whole brain using standard fractionation is approximately: _____________
    45 GY
  5. The period of organogenesis normally occurs during the _____ week(s) of fetal development
    2-8 week
  6. The radio sensitivity in tissue may be enhanced by ________________
    increasing the oxygen in tissue
  7. The phase of cellular division most resistant to radiation is the ____ phase
  8. The immediate symptoms that appear after an acute radiation exposure are called: _________
    Prodromal symptoms
  9. the development  of a radiation-induced cancer is known as a (deterministic/stochastic) effect

    Choose one
  10. Radiation interacts with tissue (uniformly/randomly)

    Choose one
  11. Cells are most sensitive during the (M,G2, S) phase of division
  12. The period over which radiation is delivered is referred to as the (protraction/fractionation)
  13. Erythematous skin reactions during fractionated radiation therapy are seen as a result of ______________________
    vascular dilation in the area
  14. The production of free radicals most often occurs from the irradiation of ____________
  15. Which of the following is a effect of radiation on DNA?
     - Cross-linking
     - Increased viscosity
     - Free radical formation
     - Hydroxyl formation
    Cross linking
  16. In a linear or non-linear threshold dose-response curves, the following is true of the response:
    Response may not occur at low doses
  17. The average energy deposited per unit of path length to a medium by ionizing radiation as it passes through that medium best describes: ______________________
    Linear energy transfer
  18. The 4 R's of radiation biology are:
    • Reoxygenation
    • Repopulation
    • Redistribution
    • Repair
  19. Which of the following would be a stochastic or late radiation response?
    Bone Marrow Suppression
    Skin Erythema
    Lung Cancer
    Lung Cancer
  20. The standard radiation used to determine RBE is:
    250 keV x-ray
  21. Without medical intervention, a person exposed to a single whole body dose of _____ may die within 10 days
    10 Gy
  22. Irradiation of the salivary glands may lead to permanent xerostomia above dose of _____ using the typical 2 Gy per treatment, 5 treatments per week fractionation scheme
    40 Gy
  23. Tissue injury ____ as the volume of tissue irradiated increases.
  24. The TD 5/5 is (higher/lower) for immature bone than for mature bone
  25. AN anticipated response to radiation dose above 55 Gy to the colon is (erythema/fistula)
  26. The following are examples of (nonstocastic.stochastic) effects:
    -The effects are never in the one exposed
    -The effects are never seen in future generations
    - The probability of occurring is related to dose
    - The severity of effects is related to dose
  27. The part of the cell between the membrane and the nucleus is known as the
  28. The primary function of the cell nucleus is
    housing DNA & RNA
  29. redness of the skin caused by a change in permeability of the capillaries is:
  30. Division of total dose into smaller dose given at intervals
  31. Liberated constituent of a molecule
    free radical
  32. The main objectives in Radiation protection include:
    prevention of radiation induced deterministic effects
  33. A grade 3 morbidity score for the skin would indicate
    confluent moist desquamation
  34. Somatic effects are:
    the effects limited to the exposed individual
  35. Ellis' formula did not accommodate:
    different tissue types with varying sensitivities
  36. Note:
    When irradiating the spleen for metastatic disease, hypo fractionation may be employed, whereas certain primary head & neck cancers may employ hyper fractionation. Briefly explain the rationale for this difference
    • head & neck cancers originating in the mucosa have a high mitotic activity and short intervals between mitotic events.
    • Hyperfractionation attempts to delay mitotic activity and synchronize cells to the most sensitive phases of division to increase cell kill.
    • The spleen stores blood cells that are very radiosensitive.
    • Hypofractionation provides the opportunity to cause cell death in any malignant cells infiltrating the organ and at the same time providing time for the sensitive normal cells to repair
  37. regarding the tolerance of tissue, as the volume irradiated increases:
    the tolerance dose decreases
  38. lethal damage:
    is irreparable and leads to cell death
  39. ionizing radiation can disrupt chemical _____ in important biologic materials
  40. The structure of DNA is referred to as a:
    Double helix
  41. Which phase of the cell cycle occurs between the two gap phases, G1 and G2
  42. A cell survival curve:
    usually has a shoulder and a straight portion
  43. Which dose effect curve implies that if radiation dose is doubled, the biologic effect will be doubled?
  44. Cellular growth and development is called
  45. Cells are about _____ water
  46. radiation would have less effect on a cell if given
    over a longer period of time