Rad Expo Final

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joesaflea
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Rad Expo Final
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2013-12-17 22:57:00
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Rad Expo Final
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  1. Which 2 factors affect size distortion? (Select all that apply)

    Select one or more:

    • OID
    • SID
  2. Name 4 ways technologists can help control patient motion.
    Four ways that technologists can help control patient motion are: using a short exposure time, communicate clearly with patient about breathing, use physical immobilization tools, and use others to help immobilize when needed.
  3. Which 3 factors affect geometric unsharpness? (Select all that apply)

    Select one or more:
    • Focal spot size
    • OID
    • SID
  4. Which is better at spatial resolution?

    Select one:
  5. Based on the following factors, what is the geometric unsharpness? (In mm)
    FSS=0.6mm, SID=62 inches, OID=2 inches
    0.02 mm
  6. A PA projection of the hand was produced with an SID of 40 inches and an OID of 0.5 inches. What is the MF? (with 3 decimal places)
    1.013
  7. Describe how poor film-screen contact will increase image unsharpness.
    Light transmitted from the intensifying screen will diverge from its origin and so it is important to have good film-screen contact.  Poor film-screen contact will expose parts of the film to light that shouldn't be exposed because of that divergent light beam and the space between film and screen.
  8. A PA projection of the chest was produced with an SID of 72 inches and an OID of 4 inches. What is the MF? (with 3 decimal places)
    1.059
  9. To increase recorded detail OID should be maximized.

    Select one:
  10. Radiographic images of structures are always magnified when compared to the actual structure.

    Select one:
  11. Why will radiographs always have some degree of unsharpness?
    Radiographs will always have some sort degree of unsharpness because of all the different variables required to make an accurate radiograph including geometric unsharpness, receptor unsharpness, and motion unsharpness.
  12. Size distortion is affected by:
    1. SID
    2. OID
    3. Tube angulation

    Select one:
  13. Which factor has the most detrimental effect on recorded detail?

    Select one:
  14. What affect does resolution have on recorded detail?

    Select one:
  15. SID is important as a photographic property and a geometric property.

    Select one:

  16. Based on the following factors, what is the geometric unsharpness? (In mm)
    FSS=1.2mm, SID=54 inches, OID=4 inches
    0.09 mm
  17. A misalignment the central ray, radiographed part, or image receptor will cause distortion.

    Select one:
  18. Shape distortion can be useful in radiographic imaging.

    Select one:
  19. Which is better at contrast resolution?

    Select one:
  20. Increasing OID _________ recorded detail.

    Select one:
  21. Which combination of factors results in the optimal image?

    Select one:
  22. Shape distortion includes:

    Select one:
    b. elongation
  23. Radiographic misrepresentation of the size or shape of the anatomic structure being imaged is:

    Select one:
  24. Magnification always results in reduced recorded detail.

    Select one:
  25. Which of these factors ONLY affects recorded detail?

    Select one:
    Focal spot size
  26. List 2 types of additive pathologies for each of the abdomen, chest, and skeleton.
    • Abdomen - aortic aneurysm, calcified stones.
    • Chest - pneumonia, atelectasis.
    • Skeleton - metastases, hydrocephalus.
  27. As compared to a patient with a 24 cm thick abdomen, imaging a patient with a 20 cm thick abdomen will result in _____________ scatter being produced and ______________ image contrast.

    Select one:
  28. List 2 types of destructive pathologies for each of the abdomen, chest, and skeleton.
    • Abdomen - aerophagia, bowel obstruction.
    • Chest - emphysema, pneumothorax.
    • Skeleton - gout, osteoporosis.































    • Air – negative contrast agent
    • Requires no change in exposure – negative contrast agent
    • Increases attenuation – positive contrast agent
    • Barium – positive contrast agent
    • Require increased exposure – positive contrast agent
    • Iodine – positive contrast agent
    • Decreases attenuation – negative contrast agent
  29. With film-screen imaging, for a given exposure technique, increasing part thickness decreases radiographic density.

    Select one:
  30. Generally speaking, what is the kVp value for a pediatric (less than 6 years old) skull compared with the adult skull?

    Select one:
  31. What affect does an increased body part thickness have on scatter?

    Select one:
  32. A misalignment in which of the following factors will cause distortion? (choose all that apply)

    Select one or more:
    x-ray tube, body part, image receptor, entry or exit point of the central ray
  33. With all other factors remaining the same, a patient with which body habitus would require the highest exposure factors?

    Select one:
  34. Generally speaking, what do additive pathologic conditions require?

    Select one:
  35. Match the following subject contrasts to the correct terms




















    B – low subject contrast, Chest – high subject contrast, Abdomen – low subject contrast, A – high subject contrast
  36. Which of the following is a destructive pathology?

    Select one:
  37. With digital imaging, the same mAs and kVp should be used for an AP lumbar spine and a lateral lumbar spine.

    Select one:
  38. Assuming all produce appropriate density images, which of the following would be the best exposure technique choice when performing a chest radiograph on an infant?

    Select one:
  39. You should always increase your technique when imaging a body part that is stabilized by a splint.

    Select one:
  40. What affect does increased scatter have on contrast?

    Select one:
    b. decreases
  41. Exposure factors used for adult skulls can be used for pediatric patients 6 years old and older.

    Select one:
  42. Which one of the following immobilizing devices requires an increase in the exposure technique?

    Select one:
  43. In general, what should you do to your technique when imaging a body part with a cast?

    Select one:
  44. In order to image a structure that is located anteriorly in the body, it is best radiographed to minimize magnification by doing a(n) _____ projection.

    Select one:
    c. Posterior-anterior
  45. What is the purpose of technique charts? (Give at least 2 reasons)
    The purposes of technique charts are: to help produce consistent images, satisfy ALARA, and to expand the life of the tube.
  46. What is the appropriate setting for backup time/mAs?

    Select one:
  47. A variable kVp-fixed mAs chart may be most effective with:

    Select one:
  48. When the radiographer is considering whether to repeat an image using AEC, it is important to determine the reason the first radiograph failed.

    Select one:
  49. AEC devices directly control the:

    Select one:
  50. What is the purpose of setting a backup time/mAs?

    Select one:
  51. Exposure time will ______ using AEC when patient thickness decreases.

    Select one:
  52. Why was automatic exposure control (AEC) originally developed?

    Select one:
  53. List and BRIEFLY discuss 4 technical considerations when using AEC.
    Four technical considerations when using AEC are: proper centering of the part, correct detector selection, kVp and mA selections, and your density selection.
  54. Why are calipers used?

    Select one:
  55. What would the result be if a film-screen radiographic examination required an exposure time shorter than the minimum response time of the AEC sensors?

    Select one:
  56. Select the correct 2 types of technique charts.

    Select one or more:
    Variable kVp/fixed mAs, Fixed kVp/variable mAs
  57. Technique charts should follow which principle?

    Select one:
  58. In order to become familiar with manual technical factors (i.e., setting mAs and kVp and not using AEC), it is very helpful to pay attention to the:

    Select one:
    a. mAs readout
  59. It is correct to call all AEC devices phototimers.

    Select one:
  60. If a part measures 14 cm and requires the use of 75 kVp, how much kVp would a part measuring 18 cm require when using a variable kVp-fixed mAs technique chart?

    Select one:
  61. When using a fixed kVp-variable mAs technique chart, if part thickness increases by 5 cm, what needs to happen to the mAs?

    Select one:
  62. Technique charts help in which of the following areas? (Choose all that apply)

    Select one or more:
    Produce consistency in image quality, Reduce repeats, Reduce exposure
  63. Where is the sensor located in an automatic exposure device that converts light into an electrical signal?

    Select one:
  64. Match the following descriptions to the proper type of AEC device.



















    • More sophisticated – Phototimers
    • Less prone to failure – Ionization chambers
    • More accurate – Phototimers
    • Most common AEC device – Ionization chambers
  65. Which automatic exposure device works by converting x-ray photons first into light and then into an electronic signal?

    Select one:
    a. Phototimer
  66. When using AEC with film-screen, what should the radiographer adjust to manipulate the overall density of the image?

    Select one:
  67. With digital imaging, AEC can be used with tabletop exams.

    Select one:
  68. Where is the sensor located in an automatic exposure device with a gas-filled chamber?

    Select one:
  69. What is the appropriate change in kVp when using a variable kVp-fixed mAs technique chart for a 1 cm change in tissue thickness?

    Select one:
  70. What kind of chart uses a kVp value that is high enough to adequately penetrate the part but does not diminish radiographic contrast?

    Select one:
  71. When comparing how radiation exposure is converted into electrical energy, what is the difference between phototimers and ionization chambers?
    Phototimers make light with photons which converts into electrical signals.  Ionization chambers are cells containing air that interacts with photons to create an electrical charge.
  72. Technique charts are still needed when using AEC.

    Select one:
  73. Briefly list and explain the 5 steps in technique chart development.
    • Step 1 - Determine phantom and radiographic factors
    • Step 2 - kVp and mAs using 15% rule
    • Step 3 - Eliminate unacceptable radiographs
    • Step 4 - Choose optimal radiograph
    • Step 5 - Extrapolate chart based on optimal image
    • Each body part requires these steps. Pick your part and make multiple images with varying techniques and choose the optimal image/technique.  Use that as you technique on the chart.
  74. AEC devices help control:

    Select one:
  75. A technique chart should be established for:

    Select one:
  76. A good time to use AEC is when the radiographer is unable to accurately center the x-ray beam

    Select one:
  77. Accurate patient measurement is most critical for the:

    Select one:
  78. What describes the shortest exposure time required for the AEC device to operate?

    Select one:
  79. When doing a CR study using AEC, what will happen to the patient exposure when changing from the -1 to +1 density setting?

    Select one:
  80. When exposure factors are selected using APR, the variables should not be adjusted.

    Select one:
  81. Which automatic exposure device works by using a gas-filled chamber?

    Select one:
  82. Which factors on a technique chart are standardized? (Choose all that apply)

    Select one or more:
    • Measuring point
    • SID
    • IR
    • Grid ratio
    • FSS
  83. When doing a film-screen study using AEC, what will happen to the density in the area of interest when changing from 70 kVp to 90 kVp?

    Select one:
    b. Density will not change

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