Part I Flashcards
(127 cards)
1
Q
-oscillation accompanied by the transfer of energy that travel through a medium or a vacuum
-has cyclic variations
A
Waves
2
Q
the back and forth movement at a regular speed
A
Oscillation
3
Q
-any sequence of changes in molecular motion
-one compression and one rarefaction
A
Cycle
4
Q
transmittal to distant regions remote from the sound source
A
Propagation
5
Q
2 Types of Propagation
A
Compression
Rarefaction
6
Q
-area of longitudinal wave where particle are spread apart (low pressure)
-occurs after compression, compressed particles intransfer energy
A
Rarefaction
7
Q
-area of the longitudinal wave where where particle are close together (high pressure) ex. soundwave
-mechanical deformation
A
Compression
8
Q
2 Types of Wave
A
Longitudinal Wave
Transverse Wave
9
Q
particle in the medium oscillates in the same direction as the wave energy propagation or PARALLEL with each other
A
Longitudinal Wave
10
Q
oscillates PERPENDICULAR to the direction as the wave displacement (perpendicular with velocity of propagation)
A
Transverse Wave
11
Q
series of compression and rarefaction, wave front - longitudinal waves
A
Sound
12
Q
reflection of incident energy pulse
A
Echoes
13
Q
T/F sound waves travel faster in solid than in gas
A
True
14
Q
4 Acoustic Variables
A
Pressure
Density
Temperature
Distance (Particle Motion)
15
Q
[acoustic variable]
-concentration of force
-force divided by the area in a fluid
-Pascal = 1 N/m²
-atm = 760 mmHg
-kg/ms² or lbs/in²
A
Pressure
16
Q
[acoustic variable]
-concentration of medium particles (matter)
-kg/m²
A
Density
17
Q
[acoustic variable]
-warming of particle within energy
-C°, F°, K
A
Temperature
18
Q
[acoustic variable]
-particle displacement between wave
-m, ft
A
Distance
19
Q
normal audible sound (Hz)
A
20 to 20, 000 Hz
20
Q
-low frequency sound
-below 20 Hz
A
Infrasound
21
Q
-above 20,000 Hz or 20 kHz
-frequency greater than upper limit of the human hearing range
A
Ultrasound
22
Q
-utilize 3 to 10 MHz
-uses ultrasound energy and acoustic properties of the body to produce image
A
Diagnostic Ultrasound
23
Q
utilize 15 to 20 MHz
A
Therapeutic Ultrasound
24
Q
-(a) pulse transmitted through medium, (b) reach tissue (c) create echoes, (d) sound is reflected
-acquire and record echoes arising from tissue interfaces
-construct “acoustic map” of tissues
A
Pulse Echo
25
[year; animal]
-naturally occurring animals produces ultrasounds
-has transceivers
1790-Bats
26
[year; person]
-discovered Piezoelectric Effect
1880-Pierre Curie
27
'piezin' Greek work, means [.. ]
To press
28
polarization of substances when they are pressed
Piezoelectric Effect
29
basic fundamental principle of ultrasound
Polarization
30
[year; person]
-published about high frequency; sound and the possibility of using sound to produce images
Roentgen
31
-"HEART" of ultrasound
-can transmit and receive sound
Transducer
32
first transducer used to detect icebergs
Hydrophone
33
-first active material in transducer
-first piezoelectric material used in transducer
-when hit with electricity, it will produce sound waves
-can produce and receive sound
Quartz
34
[event]
-developed SONAR (Sound Navigation and Ranging)
-bombard the ocean depths to know the presence of enemies
WWI
35
[year; used in..]
-transducer used in industry as a testing agent
1940s- frictional heat for sealing thermal plastic package
36
[year]
-ultrasound used in field of medicine
1950s
37
[year]
-first ultrasound machine
-big as an iron
1980s
38
2 Types of Biological Effects
Thermal Effects
Mechanical Effects
39
-biologic tissues absorb ultrasound energy and convert it to heat
-dependent in rate of heart deposition and heat removal dissipation
Thermal Effects
40
-dependent/determined on ultrasound intensity and absorption co-efficient of tissues
-ex. bone - high absorption co-efficient
heat deposition
41
-tissue temperature rises 1-2° (below damaging level)
Diagnostic Ultrasound
42
can apply damaging levels with high frequency and longer pulse duration
Some Doppler Instruments
43
-radiation pressure is an effect of [..]
Mechanical Effect
44
movement of particles in the medium or a torque of the tissue structures in the acoustic streaming
Radiation Pressure
45
steady circulatory flow
Acoustic Streaming
46
-sonically generated activity of highly compressible bodies composed of gas and/or vapor
-by high energy deposition over a sort period (short pulses)
Cavitation
47
2 Types of Cavitation
Stable Cavitation
Transient Cavitation
48
peak pulse needed to power for transient cavitation to occur
1kW/cm²
49
High Power Levels/Longer Duration Doppler Studies
[two damages]
Macroscopic Damage
Microscopic Damage
50
[damage] ex. rupturing of blood vessels, lower duration doppler studies, breaking up of cells
Macroscopic Damage
51
[damage] ex. breaking of chromosomes, changes in cell mitotic index
Microscopic Damage
52
below threshold for known adverse effects
Typical Doppler Studies
53
no bioeffects below an ISPTA (Intensity Spatial Peak Temporal Average) of [..]
100 mW/cm²
54
waves formed by variations in acoustic variable
Soundwaves
55
-particle motion parallel to wave motion
-used in soundwaves
Longitudinal Waves
56
-sound waves are classified as [..]
-requires medium to travel
-carry energy not matter
-travel in straight lines
Mechanical Waves
57
EXPLAIN Piezoelectric Effect
1. Conversion of electrical energy to mechanical energy TRANSMISSION of the sound beam
2. Conversion of mechanical energy to electrical energy RECEIVING the reflected beam information - analyzed by the UTZ machine
58
vibrates to emit mechanical sound/pressure waves (UTZ waves) when electricity is applied to it
Piezoelectric Crystal
59
Two Types of Wave Production
Continuous Wave Production
Pulse Wave Production
60
[wave production]
-more efficient
-requires two piezoelectric elements, one to transmit and one to receive
Continuous Wave Production
61
[wave production]
-uses one piezoelectric element and alternates using it to transmit and receive soundwaves
Pulse Wave Production
62
-λ
-distance travelled by one cycle
-distance between rarefaction and compression or between crests
-mm or um
Wavelength
63
-f
-no. of complete cycles per second
-Hz
Frequency
64
-T (Time)
-time duration of one cycle
-T=1/f
-inversely proportional with frequencies
-sec,ms,um
Period
65
-c
-speed at which the pressure wave ,oves through the medium
-largely determined by resistance of a medium to compression
Propagation Velocity
66
propagation velocity formula:
-c = λf
-c = √B/p
B (bulk modulus) -stiffness of a medium and resistance to compression
p (density)
67
Relationships of Propagation Velocity
↑Compressibility - c↓
↑Stiffness - c↑
↑Density - c↓
68
resistance to bend of medium
Stiffness
69
[propagation velocity]
AIR
330c
70
[propagation velocity]
LUNG
600c
71
[propagation velocity]
FAT
1,450c
72
[propagation velocity]
WATER
1,480c
73
[propagation velocity]
SOFT TISSUE
1,540c
74
[propagation velocity]
KIDNEY
1,565c
75
[propagation velocity]
LIVER
1,555c
76
[propagation velocity]
MUSCLE
1,600c
77
[propagation velocity]
BONE
4,080c
78
λ = c/f
Determined by frequency and speed
Determines spatial resolution along the direction of the beam
Ultrasound wavelength
79
p
Caused by particle displacement and pressure variation in the propagation medium
Pa= 1N/m2
14.7 psi
Pressure amplitude
80
Peak maximum or peak minimum value from the average pressure on medium
Pressure amplitude
81
Pressure amplitude of diagnostic ultrasound beams
1 MPa
82
Rate of energy production, absorption or flow
Watt (W) = J/s
Power
83
I
Loudness,distribution of particles
Amount of power per unit area
1 W/cm2 = P/cm2
Intensity
84
Wave interference patterns
Constructive
Distractive
Complex
85
2 waves with the same frequency and phase, result in a higher amplitude wave
Constructive
86
Waves of phase result in a lower amplitude output wave
Disruptive
87
Waves of different frequencies interact resulting in areas of higher and lower amplitude
Complex
88
Negative ratio of stress
Bulk Modulus
89
T/F - Decibel signal is attenuated; + signal is amplified
True
90
All transmitted waves emit smaller wavelets that also emit soundwaves
Huygen’s Principles
91
Composed of dipolar molecules
Crystalline materials
92
Natural materials [piezoelectric]
Quartz t
Tourmaline
Rochelle Salt
93
Synthetic materials [piezoelectric]
Lead zirconate titanate
Barium titanate
Lead metaniobate
Ammonium dihydrogen phosphate
Lithium sulphate
94
Intermittently transmitted
Listening time - majority of he time
Receiving reflective echoes
Pulse wave production
95
Number of cycles in a pulse
Time from beginning until end of pulse
Pulse duration
96
Wavelength times the number of cycles in a pulse
Physical length of pulse
Pulse duration
97
Pulse duration plus listening time
Time from the onset of pulse until the start of the next pulse
Pulse repetition period
98
Percentage of time that the transducer is emitting soundwaves
DF =PD/PRP
Duty Factor
99
Duty factor in [pulse prod.] [continuous prod.]
Pulse wave -low in DF bc majority is listening time rather than emitting
Continuous wave - 1 bc always emit soundwaves
100
Pulse Wave Intensities
I SPTP
I SPTA
I SATP
I SATA
I SPPA
I SAPA
S- Spatial
P- Peak/Pulse
A- Average
T- Temporal
101
Interaction of UTZ with Matter
Absorption
Reflection
Refraction
Attenuation
102
Conversion of energy of soundwaves to heat within the medium
[proportional with frequency]
Can cause thermal effects
Absorption
103
z
Give rise to differentiation in transmission and reflection of ultrasound energy
Acoustic Impedence
104
Only process where sound energy is dissipated into a medium
Absorption
105
Explains how particles of a substance behave when subjected to pressure waves
Z=pc
Kg/m2/s
Acoustic impedance
106
Differences between acoustic impedance at the interface
Determine the amount of energy reflected at the interface
Impedance mismatch
107
determined by the size and surface features of the interface
Reflection
108
A fraction of incident energy reflected by the acoustic interference
R (reflection coefficient)
109
Types of Reflectors
Speculation reflectors
Diffuse Reflectors
110
Large and relatively smooth interfaces
Reflects sounds like a “Mirror”
Speculation reflectors
111
Specular reflector examples
Diaphragm, urine filled bladder, endometrial stripe
112
T/F Echoes return to transducers only if the sound beam is perpendicular to the interface
True
113
smaller interfaces of the body where most echoes arise
Echoes are scattered in all directions
Diffuse reflectors
114
Major interaction of reflected beams
Occurs at the interface between two dissimilar materials
Reflection
115
Mediums used in reflection
Medium 1: KY jelly
Medium 2: Skin of interest
116
Change in direction of the soundwave when passing through tissues with different propagation velocities
Governed by Snell’s Law
One of the cause of misinterpretation
Refraction
117
Nonspecular reflection
Responsible for creating echoes of internal organs
Scattering
118
Scattering is prominent in these organs
Kidney
Pancreas
Spleen
Liver
119
Explain SNELL’S LAW
For a given pair of media, the ratio of the series of angle of incidence Ø1 and angle of refraction Ø2 is equal to the ratio of phase velocities (c1/c2)
120
Loss/transfer of energy to tissue as sound passes through it
Combined effects of absorption, refraction and scattering
Attenuation
121
No echo
Fluid bile (lipids), blood (hemorrhage)
Anechoic
122
Low echogenicity
Fats
Hypoechoic
123
Similar echogenicity
Isoechoic
124
Moderate to high echogenecity
Stones, fibrous plaques
Hyper echoic/echogenic
125
Strongly echogenic with acoustic shadow
Stone bone
Calcified
126
Not uniform or diverse in echogenicity
Inhomogenous/heterogenous
127
Mixed echogenicity
Solid and cystic components
Complex
