Radiology PP-X Radiation biology and protection

Home > Preview

The flashcards below were created by user haitianwifey on FreezingBlue Flashcards.


  1. What two mechanisms of radiation injury are possible
    • Ionization-produced by the photoelectric effect or Compton scatter (little effect, unless DNA)
    • Free Radical Formation-when xray photons ionize water, free radicals are formed and can cause damage
  2. What are the two Theories of Radiation Injury
    • Direct: When ionizing radiation directly hits critical areas or targets within the cell (DNA)
    • Very rare: Most x-ray photons pass thru the cell causing little or no damage
    • Indirect effects: Occur more frequently
    • x-rays absorbed within the cell and produce toxins which, in turn, cause cell damage (thus, not a direct hit by x-ray photons)
  3. Linear relationship=
    response of tissue directly related to dose
  4. Threshold relationship=
    no response until reaches a certain level or threshold
  5. Nonthreshold relationship=
    a threshold dose level for damage does not exist (no matter how small the amt. of radiation, some biologic damage occurs)
  6. WHEN DAMAGE AND DOSE ARE PLOTTED ON A GRAPH, A __________ RELATIONSHIP IS SEEN
    LINEAR, NONTHRESHOLD
  7. Stochastic Effects _____ a dose threshold and ____ increase in severity of effects.
    • do not have
    • no
  8. Non-stochastic _____ a threshold and there is ____ increase in severity with increasing absorbed dose
    • have
    • an
  9. THREE stages in sequence of rad injury are identified:
    • Latent period
    • Period of injury
    • Recovery period
  10. What is the latent period
    The time between the exposure to radiation and the observable clinical signs
  11. MOST OF THE DAMAGE CAUSED BY LOW-LEVEL RADIATION IS
    REPAIRED WITHIN THE CELLS OF THE BODY
  12. What are some determining Factors for Radiation Injury
    • Total Dose
    • Dose Rate:
    • Amount of Tissue
    • Cell Sensitivity
    • Age
  13. More radiation damage occurs in cells that are
    rapidly dividing and young cells
  14. What are some effects of large amounts of radiation over a short period
    Nausea, vomiting, diarrhea, hair loss, hemorrhage
  15. What are some effects of small amounts of radiation over a long period
    Linked to birth defects, cancer and genetic defects
  16. Somatic effects are _________ and the changes are seen in _________
    • radiation injuries that produce changes in somatic cells
    • the person irradiated
  17. Genetic effects are
    passed on to the offspring
  18. What is the most sensitive and the least sensitive cells
    • lymphatics
    • nerve cells
  19. What are the (4) Critical Organs in Dentistry
    • Thyroid gland
    • Bone marrow
    • Skin
    • Lens of the eye
  20. In dental radiography what two units of radiation methods are equivalent
    the gray and the sievert are equal
  21. _________ is the greatest source of background radiation in the U.S.
    Radon gas arising from soil
  22. What is the lead Apron/Thyroid Collar requirement
    .25mm
  23. A Rectangular Collimation and/or PID results in a _____% reduction of exposure
    60-70
  24. What are the 2 types of filtration used in the dental xray tubehead ?
    • Inherent
    • Added
  25. What is the Inherent Filtration
    when primary beam goes through glass window, insulating oil, and tubehead seal (not enough for mandated levels of filtration)
  26. What is the added filtration
    Aluminum disks placed between tubehead seal and collimator
  27. Inherent is = how many mm filtration
    .5 to 1 mm
  28. Added filtration is placed in _____ mm increments
    . 5 – 2.0
  29. Mandated Total Filtration (Inherent + Added) Above 70 kV is
    total of 2.5 mm of aluminum
  30. Mandated Total Filtration (Inherent + Added) at or below 70 kV is
    1.5 mm
  31. What is the half-value layer
    When placed in the path of the xray beam, the thickness of a specified material (for example, aluminum) that reduces the intensity by half
  32. Federal mandates: no larger than a _____ opening at PID
    2.75
  33. The operator protection GUIDELINES ARE BASED ON THE FOLLOWING RULE: _________ and operators are to stand __ feet away and at a _____ degree angle from primary beam OR:
    • AVOID THE PRIMARY BEAM
    • 6
    • 90-135
  34. What is the Maximum Permissible Dose for an operator
    5.0 rem/year (.05 Sv, 50mSv)
  35. What is the Maximum Permissible Dose for a pregnant operator
    .5mSv per month
  36. What is the Maximum Permissible Dose for a patient
    0.1 rem/year (.001Sv, 1mSv)
  37. What is the newest recommendation for calculating the Cumulative occupational dose
    “Cumulative occupational dose should not exceed age X 10mSv”

Card Set Information

Author:
haitianwifey
ID:
329628
Filename:
Radiology PP-X Radiation biology and protection
Updated:
2017-04-20 13:50:00
Tags:
Radiology PP Radiation biology protection
Folders:
Radiology
Description:
Radiology PP-X Radiation biology and protection
Show Answers:

Home > Flashcards > Print Preview