CT Intro

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Bilon
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36317
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CT Intro
Updated:
2010-09-22 18:33:07
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Intro CT
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Intro to CT
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  1. The process of creating a cross-sectional tomographic plane of any part of the body:
    Computed Tomography
  2. What measures the radiation exiting the patient and feeds back the primary data to the host computer?
    A detector assembly
  3. In the early 70's, CT scanning was only used clinically for imaging the:
    brain
  4. The first CT scanners were capable of producing only ____ images.
    Axial
  5. The differentiation of densities is referred to as:
    contrast resolution
  6. The improved contrast resolution with CT when compared to conventional is due to a reduction in the amount of:
    scattered radiation
  7. When and by whom was CT first demonstrated?
    1970, Godfery Hounsfield
  8. The early CT scanners were categorized by:
    4 generations
  9. The first generation scanners worked by the process of:
    translation/rotation
  10. First generation scanners produced a ____ beam.
    pencil
  11. First generation scan time was :
    3-5 minutes
  12. The first generation scanner had a linear tube movement known as ____ followed by a rotation of ___.
    translation, 1 degree
  13. Why was early CT limited almost exclusively to neurologic examinations?
    Slow scanning and reconstruction time
  14. Second generation scanners emitted a ____ beam measured by ____ detectors.
    fan shaped, 30
  15. Second generation scanners were _____/______ movement, but the rotation was ____ degrees between each translation.
    translation/rotation, 10
  16. Scan time of second generation scanners was ____ for a single slice.
    20 seconds
  17. Third generation scanners introduced a _____/_____ movement with ____ detectors.
    rotate/rotate, 750
  18. Third generation scanners reduced scan time to ____ per slice.
    1-10 seconds
  19. Fourth generation scanners introduced _____ movement. The tube moves ____ while the detectors are ____.
    rotate-only, around the patient, in fixed positions
  20. In contemporary CT scanners, both ___ and ___ generation designs are incorporated.
    3rd and 4th
  21. A relative comparison of x-ray attenuation of a voxel of tissue to an equal volume of water:
    CT Number, or Housefield unit
  22. Tissues that are denser than water are given ____ CT numbers whereas tissues with less density than water are given ____ CT numbers.
    positive, negative
  23. The scale of CT numbers ranges from _____ for air and _____ for dense bone.
    -1000, 14000
  24. Three main components of the CT scanner:
    Computer, Table, and Gantry
  25. The computer system used in CT has 4 basic functions:
    control of data acquisition, image reconstruction, storage of image data, and image display
  26. CT studies are removed form the limited memory of the host computer and stored independently, a process called:
    archiving
  27. The gantry is a circular device that houses the:
    x-ray tube, data acquisition system (DAS), and the detector array
  28. The gantry can be tilted forward or backward up to ____
    30 degrees.
  29. The opening within the center of the gantry is termed the ____ and measures about ____.
    aperture, 28 inches wide
  30. CT tables are made of ____ or ____ and have weight limits of ____-_____.
    low-density carbon composite or wood; 300-600 lbs
  31. The special device used for head CT examinations is called:
    a cradle
  32. The postprocessing technique which allows image reconstruction in a variety of planes without additional radiation to the patient is:
    Multiplanar Reconstruction (MPR)
  33. Original CT's were used to diagnose:
    neurologic disorders
  34. Most commonly requested CT procedures:
    head, chest and abdomen
  35. Contrast media for CT is of ____ concentration.
    low
  36. Four main factors contributing to image quality:
    spatial resolution, contrast resolution, noise and artifacts
  37. The amount of blurring in an image:
    spatial resolution
  38. The latest technology of detector arrays has ___ rows of elements.
    64
  39. Muli-slice helical CT systems are referred to as ____ CT systems because covering entire body sections is easily accomplished in a single breath-hold.
    volume
  40. The bones of the skull are categorized into ___ facial bones and ____ cranial bones.
    14, 8
  41. The brain is surrounded by three layers of protective membranes called the:
    meninges
  42. From internal to external, the meninges are:
    pia matter, arachnoid matter, and dura matter
  43. The two hemispheres of the brain are connected by the:
    corpus callosum
  44. A unique arterial anastomosis exits in the brain to protect it from sudden loss of blood supply; it is called:
    the Circle of Willis
  45. Venous drainage in the brain is accomplished by two systems:
    cerebral veins and dural venous sinuses
  46. Degree of arc angulation described by the movement of the x-ray tube and cassette during a tomographic motion
    exposure angle
  47. tomographic fulcrum remains at a fixed height
    fixed fulcrum
  48. plane of tissue that is in focus on a tomogram
    focal plane
  49. point of axis of rotation for a tomographic motion
    fulcrum
  50. Basic tomographic movement that occurs when x-ray tube and cassette movement occurs with the longitudinal axis of the tomographic table
    linear tomographic motion
  51. Tomographic principle in which the fulcrum, or axis of rotation, is raised or lowered to alter the level of the focal plane; the tabletop height remains constant.
    planigraphic principle
  52. Storage of CT images on long-term storage device such as cassette tape, magnetic tape, or optical disk.
    Archiving
  53. Same as transverse:
    Axial
  54. Preset amount of contrast injected rapidly per IV administration to visualize high-flow vascular structures
    Bolus
  55. Area of anatomy displayed by the CRT
    Field of View
  56. Determines field of view; also referred to as zoom or focal plane
    scan diameter
  57. Cancer of plasma cells in bone marrow:
    Multiple Myeloma
  58. Acquired language disorder in which there is impairment of any language modality; including producing or comprehending spoken or written language.
    Aphasia
  59. Muscle weakness on one side of the body:
    hemiparesis
  60. Why is a dry head done before administering contrast?
    To check for conditions that may be hidden by contras; prior surgeries/calcifications etc.
  61. Body section radiography:
    Tomography
  62. Basic positions for tomographic examinations:
    AP and Lateral
  63. In tomographic examinations, structures are oriented either:
    parallel or perpendicular to the tomographic plane

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