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
Reading...
Front

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

image

Play button

image

Play button

image

Progress

1/15

Click to flip

15 Cards in this Set

  • Front
  • Back
What portion of sound spectrum is ultrasound?
greater than 20,000 cycles per second (20 KHz)
What are disadvantages of US
attenuated in gaseous medium, especially at high frequencies
What are the components of longitudinal ultrasound waves
compression and rarefaction
Compression
Part of longitudinal wave with more densely packed particles
Rarefaction
component of longitudinal wave with less densely packed particles.
What type of interfaces leads to greatest ultrasound reflection?
Solid/gas interfaces and dense media. Causes poor penetration.
Why does bone reflect?
Because it has so many interfaces.
Which tissues allow greatest penetration?
Soft tissues and blood.
Define an ultrasound wave cycle.
One compression plus one rarefaction.
What is wavelength?
Distance between two similar points along the wave.
What are the wavelengths used in diagnostic ultrasound?
0.15 mm to 1.5 mm
Inversely related to frequency
What is the frequency of the sound wave?
Number of cycles per second (expressed as Hertz or Hz. Inversely related to wavelength.
What is absorption?
Transfer of ultrasound energy to tissue during propagation.
What is acoustic impedence?
The product of the density of the medium and the velocity of sound: The differences in AI between two medium determine the ratio of transmitted versus reflected sound at the interface.
What is amplitude
Magnitude of presure change along a wave. Strength of the wave in decibels.