Ultrasound Flashcards
Is US audible to the human ear
No
How is US generated
High frequency electrical generator that is part of an oscillatory circuit which puts energy through a crystal causing it to vibrate emitting sound waves
What is the crystal made of and it’s thickness
Synthetic ceramic 2-3 mm
What does the crystal convert electrical energy to
Mechanical acoustic energy
True or False:
US creates a reverse piezoelectric effect
True
What is the reverse piezoelectric effect
Voltage creating a mechanical compression to the crystal
What is the soundhead made of (3)
Ceramic, aluminum, or stainless steel plate
Is the soundhead interchangeable and why or why not
No because it generally matches the frequency of the crystal
What does the applicator house (2)
- Crystal
2. Soundhead
What is the applicator made out of
Hard insulated plastic
What type of wave do photons move along the wave
Electromagnetic
What type of wave do molecules bump into their neighbor resulting in propagation of energy
Mechanical
What are the 2 types of therapeutic ultrasound waves
- Longitudinal waves
2. Transverse waves
Can sound waves travel through a vacuum why or why not
No because they need to be able to bump into something
True or False:
US creates a wave that goes positive and negative
True
What wave type do the molecules move in the direction the wave travels and perpendicular to the direction the wave travels
Transverse waves
What wave type do molecules move along the direction the wave travels
Longitudinal waves
What is the molecular flow occurring in the same direction as the wave known as
Microstreaming
What is the near field
Area of the US beam closest to transducer
What is another name for the near field
Fresnel zone
What is the far field
Area of the US beam where wave begins to diverge
What is another name for the far field
Fraunhofer zone
What does the near field look like
Sound waves are transmitted in a straight line
What does the far field look like
Sound wave begins to diverge or scatter