Chapters 1-5 Flashcards Preview

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Flashcards in Chapters 1-5 Deck (121):
1

What does the horizontal axis represent?

x-axis

2

What does the vertical axis represent?

y-axis

3

what are some units for area?

cm2, ft2
*anything squared

4

What are some units for volume?

cm3, ft3
*anything cubed

5

What is the reciprocal of giga?

nano

6

What is the reciprocal of hecto?

centi

7

What is the reciprocal of deca

deci

8

What do all waves have in common?

all waves carry energy from one location to another.

9

What is a sound wave?

mechanical and longitudinal

10

What is defined as the effects of the medium upon the sound wave?

acoustic propagation properties

11

What is defined as the effects of the sound waves upon the tissue through which it passes?

biologic effects

12

What are the acoustic variables?

pressure, distance (particle motion), density

13

What are the acoustic parameters?

period
freq
amplitude
power
intensity
wavelength
prop speed

14

What is it called when the peaks occur at the same time and location?

in phase waves

15

what is it called when the peaks occur at different times?

out of phase waves

16

What is interference?

the combo when multiply beams arrive at the same time and location but they lose their individual characteristics at the moment and combine to make a single wave

17

What are constructive interference?

in phase and the formation of a single wave of greater amplitude than either of the components
the resulting wave is larger

18

What are destructive interference?

out of phase and the single wave is lesser amplitude and the resultant wave is smaller

19

What happens when interference of waves with different freq occurs?

when freq differs, both constructive and destructive interference occurs.

20

Define period

the time it takes to complete a cycle units of time

21

What are typical values for period?

0.06-0.5 microsecond

22

What is the source of sound determined by?

transducer and ultrasound system

23

What is the medium determined by?

the tissue

24

Can you adjust period?

no

25

Define frequency

the number of cycles that occur in one sec units hertz
cycle/sec per sec

26

Is frequency adjustable?

no

27

what are freq ranges in imaging?

2-15MHz

28

What parameters are determined by the sound source?

period, freq, amplitude, intensity, power

29

What is considered infrasound?

less than 20hz

30

what is considered audible sound?

between 20-20,000hz

31

what is considered ultrasound?

greater than 20,000hz

32

What is the relationship between freq and period?

inverse

33

What are the bigness parameters?

amplitude, intensity, power

34

What is amplitude?

the difference between the min value and the average value of the acoustic variable

35

What are units for amplitude?

pressure-pascals
density -g/cm3
particle motion (distance)- cm, inches
dB

36

What are typical pressure amplitude?

1MPa-3Mpa

37

Is amplitude adjustable?

yes

38

Define power

the rate at which work is performed
units watts

39

is power adjustable?

yes

40

True or false: amplitude decreases as sound propagates through the body

true

41

How are power and amplitude related?

power-amplitude2

42

Define intensity

concentration of energy in a sound beam
units W/cm2

43

What is the formula for intensity?

=power/area

44

Is intensity adjustable?

yes

45

how is power and intensity related?

direct

46

How are amplitude and intensity related?

intensity-amplitude2 (squared)

47

Define wavelength

the distance or length of one complete cycle
units length- mm

48

how is wavelength determined?

sound source and medium

49

is wavelength adjustable?

no

50

what is the typical value for wavelength?

0.1-0.8mm

51

how are wavelength and frequency related?

inverse

52

What is the formula for wavelength?

=propagation speed/freq

53

What is the formula for frequency?

=propagation speed/wavelength

54

Shorter wavelengths are created with higher frequency which produces ____ images.

higher quality

55

true or false: higher frequency transducer produce better quality images

true

56

Define propagation speed

the rate at which a sound waves travels through a medium
units meters per second
m/s

57

What is propagation speed determined by?

medium only

58

Is propagation speed adjustable?

no

59

what is the propagation speed in soft tissue?

1,540 m/s or 1.54 mm/microsecond or 1.54 km/s

60

Arrange these tissue types in increasing order:
gas, solid, liquid

gas, liquid, solid or
air, lung, fat, soft tissue, liver, blood, muscle, tendon, bone

61

what is the formula for propagation speed?

=freq (Hz) x wavelength (m)

62

What characteristics determine the speed of sound?

stiffness and density

63

How are stiffness and speed related?

directly

64

How are density and speed related?

inverse

65

What are some words to describe opposite of stiff?

elasticity and compressibility

66

What factors will affect a medium to travel fast?

more stiff, less dense

67

What factors will affect a medium to travel slow?

less stiff, more dense

68

What has the greatest influence of speed?

stiffness

69

five parameters that describe pulsed sound

Pulse duration
PRP
PRF
Duty factor
SPL

70

What is pulse duration?

the actual on time from the start of that pulse to the end of that pulse
"on" time, talking or transmit
units of time

71

What are typical values for pulse duration?

0.3-2.0 microseconds

72

what is pulse duration determined by?

sound source

73

is pulse duration adjustable?

no

74

What are the two formulas for pulse duration?

=#cycles x period or
=#cycles/freq

75

how are period and pulse duration related?

directly

76

how are pulse duration of freq related?

inverse

77

What type of pulses are more desirable for imaging and why?

shorter duration pulses b/c they create images of greater accuracy

78

define spatial pulse length

the distance that a pulse occupies in space from the start to the end of a pulse
units-length

79

What are typical values for SPL?

0.1-1.0 mm

80

What is SPL determined by?

source and medium

81

is SPL adjustable?

no

82

What is the formula for SPL?

=#cycles x wavelength

83

How are wavelength and SPL related?

directly

84

How are freq and SPL related?

inverse

85

Which type of pulses is more desirable in imaging?

pulses of shorter length are desirable because they create more accurate images.

86

define PRP

the time from the start of one pulse to the start of the next pulse. includes pulse duration plus listening time
units: time

87

What is PRP determined by?

sound source and imaging depth

88

is PRP adjustable?

yes

89

how is PRP and imaging depth related?

directly

90

What are the two components of PRP?

the transmit time and receive time or on and off time

91

true or false: transmit time is also called pulse duration

true

92

When is listening time longer?

with deep imaging

93

When is listening time shorter?

with shallow imaging

94

Define PRF

the number of pulse that is transmitted into the body each second
units
hertz

95

typical value for PRF?

1,000 to 10,000 hertz

96

What is PRF determined by?

sound source and maximum imaging depth

97

is PRF adjustable?

yes

98

When imaging shallow, the PRF will be ____

higher

99

When imaging deep, the PRF will be ____

lower

100

what is the relationship between PRF and frequency?

unrelated
PRF is only related to depth of view

101

What is the relationship between PRF and depth of view?

inverse

102

What is the relationship between PRF and PRP?

inverse or reciprocals

103

Define duty factor

the percentage or fraction of time that the system transmits a pulse

104

what are the typical values for duty factor?

0.2%-0.5%

105

What is the duty factor for CW?

1.0 or 100%

106

What is duty factor determined by?

sound source only

107

is duty factor adjustable?

yes

108

what is the formula for duty factor?

=pulse duration/PRP x 100

109

How is duty factor altered?

by changing imaging depth

110

What is the relationship between duty factor and depth?

inverse

111

What happens with shallow imaging?

less listening, shorter PRP, higher PRF. and higher duty factor

112

What happens with deep imaging?

more listening, longer PRP, lower PRF. and lower duty factor

113

What are key words related to intensity?

spatial, peak, average, temporal, and pulsed

114

Which is higher? spatial peak intensity or spatial average intensity?

spatial peak intensity

115

What are the temporal intensities from largest to smallest?

Itp, Imax, Ipa, Ita

116

What is the most relevant intensity with respect to tissue heating?

SPTA

117

What is another name for beam uniformity coefficient?

SP/SA factor which describes the beam in space

118

For CW, which intensities are always equal to one another?

SPTA=SPPA and SATA=SAPA

119

When CW and pulsed have the same SPTP intensities, then CW has the higher _____intensity?

SPTA

120

When CW and pulsed have the same SATP, then CW has the higher ____intensity

SATA

121

Rank the intensities from largest to smallest

SPTP-Im-SPPA-SPTA-SATA