Final Exam

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Final Exam
2010-05-17 19:23:06
Radiologic Equipment Imaging

Fluoroscopy, Mammography, Dexa, QC/QA
Show Answers:

  1. Bone density scanning also called:
    Dual Energy X-ray Absorptiometery (DEXA)
  2. Dexa is today's standard for measuring:
    Bone minderal density (BMD); or bone loss
  3. Dexa is most often performed on
    Lumbar Spine and hips
  4. Dexa is most often used to diagnose:
  5. Dexa can also assess an individuals risk for:
  6. Risk of fracture affected by:
    Age, weight, history or prior fracture, family history of osteoporotic disease, and lifestyle
  7. Bone mineral denisity is calculated by finding the difference between:
    peak energy absorbed by soft tissue and by bone
  8. Dexa score that shows the amount of bone you have as compared to a young adult of the same gender with peak bone mass.
    T Score
  9. Normal T Score
    A score above -1
  10. T score classifying osteopenia (low bone mass)
    A score between -1 and -2.5
  11. T Score identifying osteoporosis
    Score below -2.5
  12. T Score is used to estimate risk of
    developing a fracture
  13. The Dexa number that reflects the amount of bone you have compared with other people in your age group of the same size and gender.
    Z Score
  14. A DXA test cannot predict who will experience a fracture but can provide indications of
    relative risk
  15. Osteoporosis involves a gradual loss of:
  16. X-ray imaging of a selected plan of the obdy by a method that elimiates the outline of structures in other planes.
  17. Principal advantage of tomography:
    Improved contrast resolution
  18. Principal disadvantage of tomography:
    Increased patient dose
  19. X-ray tube attached mechanically to the image receptor; the tube moves in one direction while the bucky moves in the opposite direction.
    Linear Tomography
  20. Imaginary point about which the x-ray tube and image receptor moves
  21. What determines the object plane in Tomography?
    The fulcrum
  22. Anatomical structures lying within what plane are imaged clearly in tomography?
    The object plane
  23. The farther from the object plane an anatomical structure is, the more
    blurred the image will be
  24. Section thickness in tomography is determined by:
    Tomographic angle
  25. A large angle in tomography results in
    A thin section
  26. Long flexible fine spring used to introduce and position an intravascular angiographic catheter:
  27. Hollow flexible tube for insertion into a body cavity, duct, or vessel to allow passage of fluids or distend a passageway.
  28. Common uses of catheter angiography:
    To examine blood vessels in the brain, kidneys, pelvis, legs, lungs, heart, neck and abdomen
  29. X-ray tube and IR move around the head
    Panoramic tomography
  30. Images of structures above and below the object plane become more blurred as tomographic angle
  31. The thickness of tissue to be imaged is called the ____ ____ and is controlled by ____ ____.
    tomographic section/tomographic angle
  32. If the tomographic angle is less than 10 degrees, the section thickness will be ____. This is called _____.
  33. Primary function of fluoroscope:
    To provide real-time dynamic images of anatomic structures; to view motion and function
  34. What is used for the examination of moving internal structures and fluids?
  35. Who invented the fluoroscope? When?
    Thomas Edison; 1896
  36. Original Fluoroscope:
    Zinc Cadmium Sulfide backed by leaded glass
  37. Permanent fixed image taken during fluoroscopy; a small static image on a small format image receptor:
    Spot Film
  38. Fluoroscopic visualization of vessels:
  39. What is Automatic Brightness Control (ABC)?
    The image brightness selected by the radiologist is maintained automatically by varying the kVp, mAs, or both.
  40. Radiographs are visualized under illumination levels of:
    100-1000 lux
  41. LUX=
    Lumen per square meter
  42. How many rods and cones are there in the eye per cubic mm of retina?
    More than 100,000
  43. Cones are concentrated at the ___ ____ and are used for ____ vision.
    fovea centralis/photopic
  44. Rods are concentrated at the ____ of the retina and are used for ____ vision.
  45. Threshold for rod vision:
    2 lux
  46. Threshold for cone vision:
    100 lux
  47. Ability to perceive fine detail:
    Visual Acuity
  48. Detecting differences in brightness:
    Contrast Perception
  49. Developed to replace conventional fluorescent screen:
    Image intensifier
  50. An image intensifier raises illumination into the:
    Cone vision region
  51. Complex electronic device that receives the image forming x-ray beam and converts it into a visible light image of high intensity:
    Image intensifier tube
  52. X-rays that exit the patient and are incident on the image intensifier tube interact first with the:
    Input phosphor
  53. The input phosphor is composed of:
    Cesium Iodide
  54. When x-rays interact with the input phosphor, their energy is converted to:
    visible light
  55. What is bonded directly to the input phosphor with a thin transparent adhesive?
    The photocathode
  56. The photocathode responds to light from the input phosphor by emission of:
  57. The emission of electrons by the photocathode is called:
  58. The number of electrons emitted by the photoemission of the photocathode is _____ to the intensity of the incident image forming x-ray beam.
  59. Circular plate with a hole through which electrons pass to theh output phosphor.
  60. What is the potential difference maintained across the tube between the photocathode and anode?
    25,000 V
  61. Site where electrons interact and produce light:
    Output phosphor
  62. The output phosphor is composed of:
    Zinc Cadmium Sulfide
  63. What are located along the length of the image intensifier tube to ensure that the electrons are reduced to the small output phosphor?
    Electrostatic focusing lenses
  64. What is the flux gain?
    The ratio of the number of light photons at the output phosphor to the number of x-ray photons at the input phosphor
  65. Each photoelectron that arrives at the output phosphor produces how many times the light photons as were necessary to create it?
    50-70 times
  66. What is the minification gain?
    The ratio of the square of the diameter of the input phosphor to the ratio of the square of the diameter of the output phosphor
  67. What is the Brightness gain?
    The minification gain x the flux gain; the ablility of the image intensifier to increase ilumination level of the image
  68. Brightness gain of most image intensifiers:
  69. The conversion factor of most image intensifiers is:
  70. Conversion factor
    Output illumination/input exposure rate
  71. What reduces the contrast of an image with internal scatter radiation?
    Veiling glare
  72. What uses a smaller diameter to result in a magnified image in direct proportion to the ratio of diameters?
    Multifield Image intensification
  73. In magnified mode, the minification gain is____.
  74. In magnified mode ____ photoelectrons incident on the output phosphor
  75. In magnified mode, the image is _____.
  76. Magnification mode results in ____ patient dose.
  77. What effect does magnified mode in fluoroscopy have on spatial and contrast resolution.
  78. Reduction in brightness at the periphery of the image:
  79. In television fluoroscopy, the output phosphor is coupled:
    directly to the camera tube
  80. Television camera tube used most often in television fluoroscopy:
  81. The input surface of the vidicion is the same size as:
    the output phosphor
  82. The vidicion converts light from the output phosphor into an:
    electrical signal
  83. Electromagnetic coils in the television camera are used to:
    properly steer the electron beam within the tube
  84. Two methods commonly used to couple the television camera tube to the image intensifier:
    • 1. Bundle of Fiber Optics
    • 2. Lens coupling
  85. Power supply of 60Hz results in ___ television fields per second, and ____ frames per second. Each frame is ___
    60, 30, 33ms
  86. Describe interlace
    An active trace in field 2 lies between two active traces in field 1. This forms a frame.
  87. When the electron beam blanks and turns off to return to the left side of the screen, this is called:
    Horizontal retrace
  88. How many new cases of breast cancer are there yearly?
  89. How many breast cancer patients are cured with early diagnosis?
  90. Ratio of benefit to risk in mammography:
  91. What tissue is most sensitive to cancer by radiation?
  92. What percentage of breast tissue is ductal?
  93. Incidence of breast cancer is highest in what part of the breast?
    Upper outer quadrant
  94. A baseline mammogram is usually obtained before age:
  95. Optical densisty is highest with what kind of breast tissue?
  96. Low kVp is used in mammography to minimize____, maximize ____, and enhance ____.
    Compton scatter/ Photoelectric effect/ differential absorption
  97. What kVp is effective in mammography?
  98. What type of target/filter combination is best for thick, dense breasts?
  99. What type of target/filter combination is best with thin, fatty breasts?
  100. In mammography, effective focal spot is obtained with an anode angle of ____ and a tube tilt of ____.
    23 degrees/ 6 degrees
  101. The cathode is positioned toward the chest wall during mammography to make use of the:
    anode heel effect
  102. Focal spot blur in mammography results in reduced:
    spatial resolution
  103. SID of most mammography imaging systems: 60-80 cm
  104. Inherent filtration of mammography imaging systems:
    .1 mm Al equivalent
  105. Total beam filtration of mammography imaging system should never be less than:
    .5 mm Al equivalent
  106. The use of a filter of the same element as the target in mammography is done to allow ____ to expose the breast while limiting high and low ____.
  107. Compression of breast reduces:
    Motion blur, scatter, tissue superimposition, focal-spot blur, absorption blur, and patient dose.
  108. Most mammography systems have a moving grid of:
    4:1 or 5:1
  109. HTC grid ratio:
  110. Why are phototimers for mammography positioned after the IR?
    to reduce OID and improve spatial resolution
  111. Two types of AEC for mammography:
    1. Ionization chamber 2. Solid State Detector
  112. Magnification mammography requires a focal spot size no larger than:
    .1 mm
  113. When used with AEC, screen-film mammography must have a
    low absorbing back cover
  114. Quality assurance deals with:
  115. Quality Control deals with:
    Instrumentation and equipment
  116. QA is principally the responsibility of:
    the radiologist
  117. QC is principally the responsibility of:
    the medical physicist
  118. The ten step monitoring and evaluation process resolves
    identified patient care problems
  119. Pertaining to whether the patient's ultimate disease or condition agree with the radiologist's diagnosis.
    Outcome analysis
  120. Three steps of an acceptable QC program:
    Acceptance testing, monitoring and maintenance
  121. In private officies, clinics and hospitals, the QC program is established and overseen by:
    a medical physicist
  122. The most important protection characteristic of a radiographic imaging system:
  123. Collimation misalignment must not exceed
    2% of the SID
  124. Distance must be acurate within
    2% of the SID
  125. Centering must be accurate within
    1% of the SID
  126. Spatial resolution is determined principally by:
    focal spot size
  127. Focal spot size must be measured when:
    new equipment or replacement tube are installed
  128. Filtration should be evaluated annually or any time after
    a change has occured in the tube or housing
  129. 3 tools used to measure focal spot size
    slit camera, pinhole camera, star pattern
  130. What is the standard tool for measuring focal spot size?
    slit camera
  131. The star pattern is only useful for measuring focal spot sizes greater than
    .3 mm
  132. Specification of focal spot size depends on
    geometry of the tube and focusing of the electron beam
  133. An acceptable alternative to focal spot size measurement:
    Line pair test tool
  134. kVp calibration should be evaluated annually or when
    high voltage generator components have changed
  135. Measured kVp should be within
    10% of the indicated kVp
  136. For times above 10ms, exposure timer accuracy must be within
    5% of indicated time
  137. For times 10 ms or less, exposure timer accuracy should be within
  138. AEC is evaluated by exposing an image receptor through:
    varying thickness of aluminum or acryllic
  139. The accuracy of the exposure timer should be assessed annually or more frequently if repairs have been made to:
    the operating console or high voltage generator
  140. Assessing the function of the backup timer can be done by inserting a
    lead filter
  141. If the phototimer fails, the backup timer should terminate the exposure at
    600 mAs or 6 seconds
  142. The ability of a radiographic unit to produce a constant radiation output for various combinations of mA and time:
    Exposure linearity
  143. Exposure linearity must be within:
    10% for adjacent mA stations
  144. Exposure linearity is determined by a:
    precision radiation dosimeter
  145. Method of assessing exposure linearity:
    Hold exposure time constant and vary the mA
  146. Two methods to evaluate exposure reproducibility:
    1. Make a series of at least 3 exposures with the same technical factors while changing between exposures. 2. Select technique factors and hold constant for 10 exposures
  147. Sequential radiation exposures should be reproducible within:
  148. Screen cleaning should not occur less often than
    every other month
  149. Screen-film contact is evaluated:
  150. Protective apparel should be radiographed/fluoroscoped
  151. Viewbox illumination is analyzed annually with a:
  152. Filters used to determine adequacy of ABS:
    aluminum, copper, lucite, and lead
  153. As the active area of the input phosphor is increased, patient dose is:
  154. Fluoroscopic ABC should be evaluated:
  155. For conventional tomography, patient exposure should be measured for:
    the most common procedures
  156. Most frequent tomographic procedures:
    TMJ, C-spine, T-spine, Chest, IVP, Nephrotomogram
  157. In conventional tomography, section uniformity is evaluated by imaging:
    a hole in a lead sheet
  158. A 90 second film processor can handle
    500 films per hour
  159. 90 second film processor requirements:
    Water 87 degrees, developer temperature 95 degrees, high concentration chemistry, 22 second developer immersion
  160. In most facilities, processor cleaning is done
  161. Processor monitoring should be done at least
    once per day
  162. 3 types of maintenance programs for QC
    Scheduled maintenance, preventative maintenance, non-scheduled maintenance
  163. Average ESE during fluoroscopy:
  164. Skin dose during fluoro
    10 rads
  165. Skin dose during interventional procedures
    100 rads
  166. ESE for fluoroscopy should not exceed:
  167. ESE for interventional studies should not exceed
  168. Proper exposure of cassette spot film depends on:
    kVp, mAs, and sensitivity characteristics of screen-film combination
  169. ESE for cassette spot film:
    200 mR
  170. Input exposure rate to the image intensifier tube should be in the range of:
    10-40 microR/s
  171. In tomography, agreement between the indicated section level and the measure level should be within
    5 mm
  172. Incrementing from one tomographic section to the next, section level should be within
  173. QC team for mammo
    Radiologist, Mammographer, and Medical Physicist
  174. Daily QC the responsibility of:
  175. How many specific tasks does the QC mammographer have and what is the total annual time required for mammographic QC?
    12, 160 hours
  176. Daily mammo. QC tasks:
    Darkroom cleaning, processor monitoring
  177. What kind of thermometer should never be used to check developer temperature in the processor?
  178. Which end of the sensitometeric strip should be fed into the feed tray first?
    Least exposed, emulsion side down
  179. OD closest to 1.2 but not less than 1.2
    Mid density/speed index
  180. Difference between OD of 2.2 and OD closest to but not less than. 5
    Density difference/contrast index
  181. Average OD from unexposed area of the strips:
    Base + Fog
  182. MD and DD allowed to vary within:
  183. Base plus fog allowed to vary within
  184. Weekly mammography QC tasks:
    Viewbox, screen cleaning, phantom images
  185. Technique used for imaging mammographic phantom should be the same as used clinically for:
    4.5cm compressed breast, 50% glandular, 50% adipose
  186. Time or mAs values for mammographic phantom images should be within
  187. For mammographic phantom images, background OD should be ___ with a range of ____
    1.4, .2
  188. For mammographic phantom images, DD should be ___ with a range of ___
    .4, .05
  189. Monthly mammographic QC tasks:
    Visual checklist
  190. Quarterly mammo QC tasks:
    Repeat analysis, analysis of fixer retention, conferense w/radiologist
  191. Quarterly repeat analysis valid if patient volume results in at least:
    250 exams
  192. Analysis of fixer retention in film is used as an indicator of:
    archival quality
  193. They hypo estimator should not result in more than
  194. Semi-annual mammographic QC tasks:
    Screen/film contact, compression, darkroom fog
  195. Safelight or fluorescent light fog should not exceed
  196. Background of the phantom image should be: