Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

32 Cards in this Set

  • Front
  • Back
Who invented the fluoroscope in 1896?
Thomas Edison
What is used for examining moving internal structures and fluids?
The fluoroscope.
If less than 5 mA are used in fluorosocopy, why is it that pt dose is considerably higher during fluoroscopic exams than with radiographic exams which use hundreds of mA?
In fluoroscopy, the x-ray beam exposes the pt for a considerably longer time.
What is the principal advantage of image intensified fluoroscopy over earlier fluoroscopy?
Increased image brightness.
Which structures in the human eye are responsible for the sensation of vision?
Rods and cones. Rods = night vision (scotopic); colorblind. Cones = daylight vision (photopic); can perceive color.
The brightness of the fluoroscopic image depends primarily on what 3 things?
Anatomy being examined, kVp and mA.
When an x-ray interacts with the input phosphor, its energy is converted into what?
Visible light.
What component of the image intensifier emits electrons when illuminated by the input phosphor?
The photocathode.
What is electron emission following light stimulation?
What is electron emission following heat stimulation?
Thermionic emission.
Which portion of the image intensifier do the electrons interact & produce light?
The output phosphor.
What is the ratio of light photons at the output phosphor to the number of x-rays at the input phosphor?
Flux gain.
What is the ability of the image intensifier to increase the illumination level of the image?
Brightness gain.
Increased magnification of image using magnification mode during fluoroscopy results in what?
Decreased minification, ABC (automatic brightness control) increases mA consequently increasing pt dose (because mag'd images are dimmer).
How wide is the input & output phosphor?
Input phosphor: 5 - 12".
Output phosphor: 1/2 - 1".
What 3 things does magnification mode result in?
Better contrast resolution, better spatial resolution, & higher pt dose.
What is spatial resolution measured in?
LP/MM = Line pairs per millimeter.
What type of camera is most often used in television fluoroscopy?
What does the tv camera tube do?
It converts light image from the output phosphor to an electrical signal that is sent to the tv monitor, where it can be reconstructed as an image on the tv screen.
What are some advantages of the tv camera tube?
Can increase brightness level & controlled electronically without increased pt dose, as well as allow for storage of image in its electronic form.
What does the target assembly of the vidicon consist of?
Outside layer = faceplate/window.
Inside layer = signal plate which is a thin layer of metal/graphite.
Photoconductive layer = Target made of antimony trisulfide.
What part of the target assembly of a vidicon conducts video signal out of the tube into the external video circuit?
Signal plate.
What part of the target assembly of a vidicon conducts electrons when illuminated and behaves as an insulator when dark?
What are the 5 ways that x-rays interact with matter?
Coherent scatter, aka Thomspon, classical.
Compton effect.
Photoelectric effect.
Pair production.
Describe coherent scattering.
AKA Thomspon, classical. X-rays has < 10 keV. Low energy. Little importance to radiology. Can reduce image contrast. Scatter energy = Incident energy, but scatters in different direction.
Describe Compton effect.
Occurs with moderate - high energies. Outer electron is ionized. Reduces image contrast. Source of occupational rad exposure (especially in fluoro). Incident energy > scatter energy and changes direction.
Describe photoelectric effect.
Occurs with low - moderate energies. Affects inner shell electron, producing characteristic x-ray production after photoelectric interaction.
Describe pair production.
Doesn't occur during x-ray imaging. Needs 1.02 MeV to occur. Affects nuclear electric field. X-ray disappears. 2 electrons appear: a positively charged positron and a negatively charged negatron.
Describe photodisintegration.
Doesn't occur in diagnostic radiology. Needs 10 MeV to occur. Nucleon is emitted from nucleus.
What are 2 important ways that x-rays can interact with tissue?
Compton (occupational dose) and photoelectric effect (pt dose).
What are 2 methods of x-ray production important to radiography?
Bremstrahlung (braking) and characteristic (k-shell knockout).
What is the difference in x-ray interaction called?
Differential absorption, which increases when kVp is decreased to obtain short-scale images. However, this results in higher pt dose.