FInal part I

Question 1

1. 25 million Hz, another way to write it?

Answer 1

2.5 x 10 ^ 7 or 25MHz

Question 2

2. What do we call a sound that is below the audible range?

Answer 2

Infrasound

Question 3

3. Know about which items are determined by the sound source

Answer 3

Frequency, Period, amplitude, intensity, power

Question 4

4. Which would be determined by medium and sound

Answer 4

Wavelength

Question 5

5. Determined only by the medium?

Answer 5

Propagation speed

Question 6

6. Acoustic variables?

Answer 6

Density, Distance, Pressure

Question 7

7. Going to have some choices for frequency and which ones has the longest wave length

Answer 7

Lowest frequency has the longest wavelength.

Question 8

8. If the intensity remains the same, the power is doubled, what happens to beam area?

Answer 8

Doubles. I = P/A

Question 9

9. What term describes the start of the pulse to the end of the pulse?

Answer 9

Pulse duration

Question 10

10. What kind of scale has dB, mathematical representation?

Answer 10

Logarithmic, relative scale that requires two intensities.

Question 11

11. Every 3 dB means the intensity will do what?

Answer 11

Double

Question 12

12. Initial intensity is less than normal intensity the gain is what?

Answer 12

Positive

Question 13

13. Rayleigh scattering is related to?

Answer 13

Frequency to the 4th.

Question 14

14. In soft tissue, attenuation coefficient is directly related to what?

Answer 14

Frequency

Question 15

15. Lots of questions on attenuation and speed? Which media will have the greatest attenuation and which doesn’t

Answer 15

Air>bone>muscle >soft tissue>blood>water

Question 16

16. 2 PZT, same material, thicker will make a pulse transducer with?

Answer 16

Lower frequency and slower speeds

Question 17

17. PZT exceeds the curie point what happens to the PZT?

Answer 17

Depolarization

Question 18

18. What are the other names for PZT

Answer 18

Ceramic,active element, crystal, lead zirconate titanate

Question 19

19. Which component of the transducer reduces the ringing of the pulse?

Answer 19

Backing material

Question 20

20. Which crystal will produce sound with the lowest frequency?

Answer 20

Thicker

Question 21

21. Damping material improves what resolution?

Answer 21

Longitudinal resolution page 126 question 9 on the Q and A (Harley S.)

Question 22

21. Damping material improves what resolution?

Answer 22

Longitudinal resolution page 126 question 9 on the Q and Q (Harley S.)

Question 23

22. If the frequency of the electrical citation of the voltage in a pulsed wave transducer is 6 hertz, what is the operating frequency of the transducer?

Answer 23

In pulsed wave transducers, the frequency of sound is not determined by the electrical signal.

Question 24

23. Impedance of a transducer of the active element is … rayls, to the skin is …. Rayls, what would be the acceptable matching layer?

Answer 24

Between the PZT and skin.

Question 25

24.. Which transducer component has a thin barrier of cork or rubber and isolates the internal components from the transducers case

Answer 25

Acoustic Insulator (JL p 115)

Question 26

25. Which component of trans increases the efficiency of sound energy transfer of the active element in the body

Answer 26

Maching layer

Question 27

26. Frequency and near zone length are related in what way?

Answer 27

directly

Question 28

27. Two trans have the same diameter the first probe has a 6Mhz frequency and second has 8Mhz freq which beam will have a shallower focus

Answer 28

6 MHz, smaller diameter, lower frequency

Question 29

28. Which of the following probes will create a beam with the least divergence

Answer 29

. For least divergence we will see larger diameter crystals and higher frequency p 140 box

Question 30

29. Which probe will have more divergence

Answer 30

A probe that has a smaller diameter crystal and a low frequency will create more divergence pg 140 box

Question 31

30. What determines the freq of sound created by a pulsed wave transducer?

Answer 31

The active element the speed of sound in PZT and the thickness of the PZT

Question 32

31. What determines the focal length of sound beam

Answer 32

The characteristics of the active element, transducer diameter and the freq of sound

Question 33

32. Which of the transducer has the best lateral resolution in the far field

Answer 33

Larger diameter crystals improve lateral resolution in the far field p 139

Question 34

33. Sound beam is created by round PZT of diameter of 10mm the focal depth is 8cm what diameter is the sound beam at the depth of 8cm

Answer 34

a. 5mm the diameter is half at the focal depth of 8. Because it is in the middle p 134

Question 35

34. Lateral resolution need to know the other names for it which ones belong and which ones

Answer 35

lateral angular transverse auimuthal. It is the ability to distinctly identify two structures that are very close together when they are side by side. P 151

Question 36

35. Lateral resolution is what to the beam?

Answer 36

Perpendicular p 151

Question 37

36. Know about characteristics of lateral resolution

Answer 37

a. –is determined by width of the sound beam narrower beams have better resolution. Is best at foucus where beam is narrowest Lateral resolution= beam diameter.

Question 38

37. Several different methods are used to describe us beam intensity these different methods important in what kind of studies?

Answer 38

Study of bioeffects p 70

Question 39

38. When reporting a beams intensity at the location where it is maximum is referred to as what

Answer 39

spatial peak intensity pg 70

Question 40

39. What are units for intensity

Answer 40

W/cm2

Question 41

40. What is measured where intensity is max and averaged over transit time

Answer 41

Sppa spatial peak pulse average. P73

Question 42

41. Intensity is maximum and average over all time, transmit and receive?

Answer 42

Spta spatial peak temporal average p 73

Question 43

42. Which intensity is measure over the entire cross-section of crossbeam and time?

Answer 43

Sata spatial average temporal average p 73

Question 44

43. All of the terms that mean the same as normal incidence?

Answer 44

PORN perpendicular orthogonal right angle nighty degrees p 91

Question 45

44. What is the sound beam before it hits the boundary?

Answer 45

Incident intensity p 92

Question 46

45. The portion of the incident intensity after striking the boundary continues on what is that called?

Answer 46

Transmitted intensity p 92

Question 47

46. The half value layer thickness depends on which factors

Answer 47

medium and the frequency of sound p87

Question 48

47. If we have normal incidence that means that the sound beam strikes the boundary at how many degrees

Answer 48

90 degrees see question 38 p 91

Question 49

48. Sound waves with an intensity with 50 w/cm2, strikes back completely, what is the intensity reflection coefficient?

Answer 49

100percent p 94 Q2

Question 50

49. Sound wave strikes the same intensity 50 wcm2 totally reflected what is the reflected intensity?

Answer 50

50w/cm^2

Question 51

50. If the intensity reflection coefficient 99.9%, what percent is transmitted into the body?

Answer 51

.1 p99

Question 52

51. W normal incidence reflection depends upon different what? What do you have to have normal incidence

Answer 52

Impedance difference between the two media on either side of a boundary p 98

Question 53

52. What type of incidence do we not know anything about?

Answer 53

Oblique

Question 54

53. Specular reflections arise when the interface is what?

Answer 54

Smooth

Question 55

58. 2 waves travel through the medium at the same time and arrive at the same time what event takes place

Answer 55

Interference

Question 56

59. Which will create fastest speed of sound?

Answer 56

Thinner PZT, higher frequency

Question 57

54. Transmission with a bend is what?

Answer 57

Refraction

Question 58

55. If we have oblique incidence and different speeds, what will occur?

Answer 58

Refraction p 103

Question 59

56. What does snells law describe?

Answer 59

Refraction

Question 60

57. Sound waves strike a boundary at normal incidence the impedance of the media are identical what percent of the sound wave is refracted

Answer 60

None will reflect reflections don’t happen if no impedance difference p95

Question 61

58. 2 waves travel through the medium at the same time and arrive at the same time what event takes place

Answer 61

interference

Question 62

59. Which will create fastest speed of sound?

Answer 62

Thinner PZT, higher frequency

Question 63

60. 3MHz through 2 medium, attenuation 5 dB in a, 6db in b, what is the total attenuation of the sound beam as it travel through both media?

Answer 63

11dB

Question 64

61. Which are of the following are considered contributors to attenuation and which is the most important of those contributors

Answer 64

Reflection scattering and absorption p 81 Absorption p 84

Question 65

62. As path length increases and attenuation coefficient in soft tissue does what as well

Answer 65

remains the same (JL p 89 #13)

Question 66

63. Attenuation in soft tissue is less than which of the following?

Answer 66

Which attenuates more than soft tissue … muscle bone lung and air p 86

Question 67

64. Impedance is a characteristic of what?

Answer 67

Reflection p 88

Question 68

65. Reflections occur if only the 2 medium at the boundary have different what?

Answer 68

impedances p 96 from Q&A

Question 69

67. Low freq trans is best at imaging what type of structures

Answer 69

deep

Question 70

q68. Ability to distinguish to objects close together is what?

Answer 70

When parallel its axial when side by side its lateral | resolution

Question 71

69. Which of the following is the best to image the thyroid

Answer 71

High freq probe 7-9 Mhz

Question 72

70. What is the best estimate for attenuation coefficient for sound traveling in soft tissue

Answer 72

One half the frequency p 85 atten coef = freq /2

Question 73

71. Attenuation is determined by what 2 factors

Answer 73

Path length and frequency of sound p 80

Question 74

72. Know what contributes to attenuation

Answer 74

Reflection, scattering and absorption (JL p81)

Question 75

74. When a boundary is rough the reflected sound is disorganized and random what is that called

Answer 75

Diffuse or backscatter

Question 76

75. Time of flight is known, what else can you determine?

Answer 76

We can know the reflector depth and the total distance traveled p 108

Question 77

76. When one reflector is 2X as deep as the other reflector, time of flight for deeper reflector?

Answer 77

twice as long

Question 78

77. Sound wave is created by transducer, reflection off and returns, 10 cm depth, 2 sec time

Answer 78

10cm | 20cm (time of flight)/ 2s = 10cm JL ESP bottom of 52

Question 79

78. Time needed for a pulse to travel from a transducer to the reflector is called a what?

Answer 79

Go return time and or time of flight p 107

Question 80

79. Sound wave is created by transducer, reflection returns is 52microseconds, reflector depth?

Answer 80

4cm p 108

Question 81

80. Max imaging depth is 4 cm, go to 8 cm, what happens to PRP?

Answer 81

It gets longer p 109

Question 82

83. Freq increases the numerical value of LARD res does what?

Answer 82

decrease

Question 83

81. Go return is 39 microsecondss, total distance traveled?

Answer 83

a. 6cm p 108

Question 84

82. Axial res deals with structures that are what to the sound beam

Answer 84

Parallel

Question 85

84. 2 different transducer different pulse, 5 MHz, which will more likely to create better image in regards to axial resolution

Answer 85

Similar Question #10, pg 150

Question 86

85. Conservation of energy

Answer 86

Pg 97, 99

Question 87

87. Which one has less biological effects focus or unfocus

Answer 87

Focus