Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

ultrasound physics > exam 1 review > Flashcards

exam 1 review Flashcards

(73 cards)

Start Studying
1
Q

Attenuation coefficient in blood

A

0.125 dB/cm*MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Attenuation coefficient in soft tissue

A

0.5 dB/cm*MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Attenuation coefficient in muscle

A

1.0 dB/cm*MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Attenuation coefficient in bone

A

20.0 dB/cm*MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Speed of sound in soft tissue

A

1540 m/s or 1.54 mm/microsecond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Reflection percentage in soft tissue-soft tissue

A

< 1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Reflection percentage in soft tissue-bone

A

10-60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Reflection percentage in soft tissue-air

A

> 99%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Round trip time for sound to travel 1 cm

A

13 microseconds/cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

wavelength equation

A

wavelength= propagation velocity (c)/frequency (f)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

distance equation

A

distance= speed * time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

density equation

A

density= mass/volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

frequency equation

A

frequency * period= 1 (reciprocal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

amplitude equation

A

crest-baseline or trough-baseline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

power equation

A

energy/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

intensity equation

A

power/area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

total attenuation equation

A

TA= attenuation coefficient * MHz * image depth (cm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

impedance equation

A

density * velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

half intensity depth (HID) equation (for soft tissue only)

A

6/frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

attenuation coefficient equation (for soft tissue only)

A

frequency/2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Waves carry ___?

A

Waves carry energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What kind of wave is sound?

A

Sound is a mechanical, longitudinal wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Wave classification

A

Mechanical (needs a medium) vs. electromagnetic (will work in a medium or vacuum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Transverse wave propagation

A

Transverse waves propagate perpendicular to the wave direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Longitudinal wave propagation
Consist of compressions and rarefactions, propagates in the same direction
26
Acoustic variables
Measures sound (determined entirely by the medium). 1. pressure 2. density 3. temperature 4. particle motion (distance)
27
Most common unit for pressure
Pascals
28
In human tissue, if density increases, stiffness will ___?
increase
29
If the intensity/power doubles, what is the decibel value?
+ 3dB
30
If the amplitude doubles, what is the decibel value?
+ 6dB
31
If the intensity/power increases 10X, what is the decibel value?
+ 10dB
32
If the amplitude increases by 10X, what is the decibel value?
+ 20dB
33
If the intensity/power halves, what is the decibel value?
- 3dB
34
If the amplitude halves, what is the decibel value?
- 6dB
35
If the intensity/power decreases by 1/10, what is the decibel value?
- 10dB
36
If the amplitude decreases by 1/10, what is the decibel value?
- 20dB
37
What is attenuation?
A decrease in wave intensity
38
What are the 3 things attenuation is caused by?
1. Absorption 2. Reflection 3. Refraction
39
What is the most dominant form of attenuation in ultrasound?
Absorption
40
What 2 things measure attenuation?
Attenuation coefficient and Half value layer/half intensity depth
41
Reflection is caused by ____?
Impedance (z)
42
Refraction is caused by ___?
Speed of sounds
43
Specular reflection
- smooth, angle dependent, strong echoes - not proportional to frequency - ex: diaphragm, liver capsule, pericardium * think of a mirror*
44
non-specular reflection
diffuse, scattering and Rayleigh
45
diffuse reflection
- rough, irregular, not angle dependent, weak echoes - not proportional to frequency - reflections scatter in random, chaotic directions
46
scattering
- small objects, not angle dependent, weaker echoes - proportional to frequency - reflections scatter in random, chaotic directions
47
Rayleigh
- very, very small objects (red blood cells), not angle dependent, weakest echoes - proportional to frequency(4) - reflections scatter equally in all directions
48
The greater the mismatch of impedance, the ____ the reflection
greater. There needs to be a mismatch of impedance for reflection to occur.
49
Z1=Z2
no reflection, 100% transmitted
50
Z1 >> Z2
100% reflected, 0% transmitted
51
Z2 >> Z1
100% reflected, 0% transmitted
52
Refraction
-Bending of a wave at the interface between two media with different speeds of sound
53
What two things need to occur for refraction to happen?
1. A change in propagation speeds | 2. an incident angle that is NOT perpendicular to the interface (boundary)
54
Snell's law measures ___?
Refraction
55
What happens if the incident angle reaches the critical angle?
The result is a loss of transmission and 100% reflected
56
Fast to Slow bends _____ the normal
Fast to Slow bends Towards the normal (FST)
57
Slow to Fast bends ____ the normal
Slow to Fast bends Away from the normal (SFA)
58
Amplitude is measured in ___?
Volts
59
What determines the speed of sound through a particular medium?
Stiffness and density
60
Unit of measurement for attenuation coefficient
dB/cm*MHz
61
Unit of measurement for HVL or HID
usually cm but can be any length measurement
62
Characteristics of Absorption
- caused by friction - directly exponentially proportional to frequency - directly proportional to viscosity * there is less absorption in body fluids than soft tissue*
63
Cycle, wavelength, period and frequency are all determined entirely by the ____.
Transducer
64
Is the speed of sound faster in air or bone?
air= 347 m/s bone= 4080 m/s Speed of sound is faster in bone
65
Attenuation in air is low, extremely low or extremely high?
Attenuation in air is extremely high
66
Attenuation in water is high, extremely low or intermediate?
Attenuation in water is extremely low
67
sound wave frequencies (infrasound, audible, and ultrasound)
infrasound: < 20Hz audible sound: 20 Hz-20 kHz ultrasound: >20kHz diagnostic ultrasound: 2 MHz-20 MHz
68
If the frequency increases, the wavelength will ____.
The wavelength halves
69
What causes a wave?
Vibrations cause waves
70
What parameter(s) are determined by both the sound source and the medium?
Wavelength
71
What parameter(s) are determined by the sound source only?
Period, frequency, amplitude, power and intensity
72
What parameter(s) are determined by the medium only?
Speed
73
Unit for impedance
Rayls

ultrasound physics (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions