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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

What is 1 joule equal to

The energy expended in 1 second by an electric current of 1 ampere in a resistance of 1 ohm