Flashcards in Ultrasound Deck (116)
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1
Is US audible to the human ear
No
2
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
3
What is the crystal made of and it's thickness
Synthetic ceramic 2-3 mm
4
What does the crystal convert electrical energy to
Mechanical acoustic energy
5
True or False:
US creates a reverse piezoelectric effect
True
6
What is the reverse piezoelectric effect
Voltage creating a mechanical compression to the crystal
7
What is the soundhead made of (3)
Ceramic, aluminum, or stainless steel plate
8
Is the soundhead interchangeable and why or why not
No because it generally matches the frequency of the crystal
9
What does the applicator house (2)
1. Crystal
2. Soundhead
10
What is the applicator made out of
Hard insulated plastic
11
What type of wave do photons move along the wave
Electromagnetic
12
What type of wave do molecules bump into their neighbor resulting in propagation of energy
Mechanical
13
What are the 2 types of therapeutic ultrasound waves
1. Longitudinal waves
2. Transverse waves
14
Can sound waves travel through a vacuum why or why not
No because they need to be able to bump into something
15
True or False:
US creates a wave that goes positive and negative
True
16
What wave type do the molecules move in the direction the wave travels and perpendicular to the direction the wave travels
Transverse waves
17
What wave type do molecules move along the direction the wave travels
Longitudinal waves
18
What is the molecular flow occurring in the same direction as the wave known as
Microstreaming
19
What is the near field
Area of the US beam closest to transducer
20
What is another name for the near field
Fresnel zone
21
What is the far field
Area of the US beam where wave begins to diverge
22
What is another name for the far field
Fraunhofer zone
23
What does the near field look like
Sound waves are transmitted in a straight line
24
What does the far field look like
Sound wave begins to diverge or scatter
25
What are rarefactions
Dispersion of molecules
26
When do rarefactions occur during US
The peak of the wave
27
When does compression occur during US
The valley of the wave
28
What is power
Amount of energy per unit of time
29
1W equals what
1 joule/sec
30
