Radiation Protection and Safety(Ch. 5)-Mosby Board Review Questions

Card Set Information

Author:
jaxkaty5437
ID:
265549
Filename:
Radiation Protection and Safety(Ch. 5)-Mosby Board Review Questions
Updated:
2014-03-08 17:28:46
Tags:
Radiation Therapy
Folders:
Mosby Board Review Questions,RTT Board Review
Description:
Radiation Protection and Safety(Ch. 5)-Mosby Board Review Questions
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user jaxkaty5437 on FreezingBlue Flashcards. What would you like to do?


  1. According to the current recommendations, which of the following would have the highest dose limit:
    a. lens of the eye
    b. the hands of a member of the general public
    c. the embryo-fetus
    d. the hands of a pregnant therapist
    • a. lens of the eye
    • b. the hands of a member of the general public
    • c. the embryo-fetus
    • d. the hands of a pregnant therapist
  2. *According to the current recommendations, the guidelines levels for cumulative exposures for a 30 yr old occupational worker with three yrs experience:
    300 mSv (30 rem)
  3. *It is recommended that radiation exposure to the fetus should not exceed___for the entire gestation.
    0.5 rem
  4. Which of the following would not normally be used to monitor radiation dose exposure:
    a. film badge
    b. TLD
    c. cutie pie
    d. pocket dosimeter
    • a. film badge
    • b. TLD
    • c. cutie pie
    • d. pocket dosimeter
  5. *The roentgen is a unit of measurement that specifies the ____of air by x-rays or gamma radiation.
    ionization
  6. *The term quality factor(Q):
    varies with different types of radiation
  7. Any container in which radionuclides are transferred, stored, or used must have a label saying:
    Caution-Radioactive Material
  8. *The organization in the US that is principally responsible for recommending radiation dose limits is the ___.
    NRC
  9. The annual dose limit for occupational worker's lens is ___.
    15 rem (150 mSv)
  10. *The annual dose limit for the occupational worker's skin is____.
    50 rem (500 mSv)
  11. The fraction of time that a radiation beam is directed at a specific barrier is the ____.
    use factor
  12. *The annual radiation dose to the lung from radon gas is estimated to be ____
    0.2 rem/yr

    (2 mSv, 200 mrem)
  13. a)The survey meter shows an exposure rate of 300 mrem/hr at 3 ft from the source during the loading of a Fletcher intraacavitary applicator, and the duration of the procedure is expected to be 6 minutes, what would the exposure be for  person standing 3 ft form the sources?

    b)What would the exposure be for the same person if the where 2 ft from the source?
    • a) 6 min =0.1 hr
    • 0.1 x 300 mrem= 30 mrem

    b) I2=30(3/2)2 =67.5 mrem
  14. *The dose rate is 0.5 rem/min at 40 ft away from a source. An office will be constructed 20 ft away the source. An individual will occupy this office 8 hrs/day 5 days/wk and is allowed to receive 10 mrem/wk. How many 10th value layers of material will be needed?
    • 40 hrs x 60 min =2400 min
    • I2 =0.5(40/20)2=2 rem/min x 2400 min=4800 rem/wk at 2 ft

    • 4800 rem= 4,800,000 mrem
    • 4,800,000=0.000002
    • 0.1x =0.000002
    • Log(0.1x )= Log(0.000002)
    • -1x=-5.689
    • x=5.69

    5.7 tenth value layers
  15. A linac accomodates 35 patients/day, 5 days a week. The average number of fields per patient is 4 and the average dose per field is 45 cGy. Calculate the workload:
    35 x 5 x 4 x 45 cGy=31500

    315 Gy/wk
  16. *If the HVL for Co-60 is 1.1 cm of lead, what percent of transmission is expected using 4.4 cm of lead as a barrier?
    • 4.4/1.1=4 HVL
    • 0.54=0.0625

    6.25 %
  17. Compare how dose is measure using a film badge and a TLD:
    • Film Badge: Crystals in the emulsion on the film badge are transformed, film is processed-density is measured with a densitometer to measure dose
    • TLD: Lithium fluoride crystals trap electrons when exposed in the TLD. When the TLD is heated, trapped electrons are released in the form of light.Light photons are proportional to dose
  18. *Compare how exposure is measured in using an ion chamber and a Fricke dosimeter:
    • Ion chamber measure ionization of air, or migration of charges between charged plates by the liberation of electrons.
    • Fricke dosimeter relies on chemical reactions. Ferrous sulfate(Fe2+) is oxidized when exposed to radiation and becomes Fe3+ ions.
  19. Dose equivalent is measured in units of:
    Sievert (or rem)
  20. *T/F:
    Maximum exposure rate at a specific distance from the patient following the insertion of radioactive sources can be measured with TLDs
    FALSE

    (ION CHAMBER USED)
  21. *T/F
    The requirement for barrier protection in walls/ceiling for a given radiation is reduced when there is a beam stopper on the treatment unit.
    TRUE
  22. The agency that regulates the use of radiation producing machines is the:
    FDA
  23. *An example of a deterministic effects is:(pick one or any)
    1)Carcinogenesis
    2)Genetic effects
    3)Birth Defects
    4)Cataracts
    • 1)Carcinogenesis
    • 2)Genetic effects
    • 3)Birth Defects
    • 4)Cataracts
  24. The radiation detection device that would be useful in locating a lost radioactive source would be:
    Geiger-Muller counter
  25. *The largest dose from natural background  radiation comes from:
    1)Terrestrial
    2)Radon
    3)Cosmic
    4)Internal
    • 1)Terrestrial
    • 2)Radon
    • 3)Cosmic
    • 4)Internal
  26. *The amount of energy absorbed in a medium is expressed in units of:
    Gray
  27. *One major contributor of _____radiation is Potassium-40.
    internal
  28. *_____radiation varies according to the composition of the soil.
    terrestrial
  29. The two main types of background radiation are:
    cosmic and terrestrial
  30. *The exposure from cosmic rays at sea level is lower than the exposure in Denver because:
    The altitude is higher in Denver
  31. *What quantity is measured directly by the TLD?
    absorbed dose
  32. *Appropriate disposal of radioactive sources include:(Pick any or all)
    1)Transfer to authorized recipient
    2)Incineration
    3)Burial
    ALL
  33. *The radioactive source inventory room should have a sign that reads:
    Caution:Radioactive Material
  34. The workload describes:
    How much the primary beam is in use
  35. *In the construction of a new RT center, the choices for primary barriers include concrete, lead, and iron. Measure for measure, I would need more_______for adequate absorption.
    Concrete
  36. The HVL for a 6x beam is 22 mm of lead. It's linear attenuation coefficient is:
    • HVL=.693/μ
    • 22=.693/μ
    • 22μ=.693
    • μ=.693/22=0.0315 mm-1
  37. *When a radiation worker is away from work, it is best to store his film badge:
    In a safe place away from the source of radiation
  38. *Patients undergoing I131 thyroid ablation should not be released from the facility until survey meters read less than ___mrem/hr at ___ m
    5 mrem/hr at 1 m
  39. Internal radiation exposure comes from radioactive materials in our body such as:
    Hydrogen-3
  40. *Radioactive sources should be transported around the treatment facility in:
    shielded containers
  41. Nursing and other pt care staff caring for pt undergoing LDR brachy should:
    Use standard precautions and perform duties as quickly as possible
  42. *A  monthly radiation exposure report says an employee received 0.5 Sv. If the source of exposure was gamma radiation, the translation to absorbed dose would be:
    0.5 Sv=0.5 Gy
  43. *How many HVLs reduce the exposure to 2%?
    • 0.5x = 0.02
    • Log (0.5x )  = Log (0.02)
    • -0.301 x= -1.698
    • x=5.64
    • 5.6 HVL
  44. Three TVLs reduce transmission to ____%:
    • 0.13=0.001
    • 0.1 %
  45. *The shielding around stored radioisotopes must be adequete to radiation levels to less than ___mrem/hr at ___meter.
    2 mrem/hr at 1 meter.
  46. *The linear coefficient  for a certain megavoltage beam  using concrete is
    0.089 cm-1 , what is the HVL? How much concrete is required to reduce the beam to 2%
    • HVL=.693/0.089
    • 7.8 cm


    • 0.5=0.02
    • Log(0.5x) =Log(0.02)
    • -.301x=-1.69
    • x=5.64 HVLs  x 7.8 cm=43.79
    • 43.8 cm

What would you like to do?

Home > Flashcards > Print Preview