Intensities Ch 5 Flashcards

1
Q

the beam’s power divided by it’s area

A

Intensity

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2
Q

Five key words related to reporting intensities of pulsed waves

A
  • SPATIAL
  • PEAK
  • AVERAGE
  • TEMPORAL
  • PULSED
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3
Q

Refers to distance or space,

does not have the same intensity at different locations within the beam

A

Spatial Intensity

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4
Q

Number of possibilities used to measure spatial intensity

A

Two possiblities, Isp and Isa

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5
Q

The beams intensity at the location where it is maximum

A

Isp (spatial peak intensity)

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6
Q

The average intensity across the beam’s entire cross-sectional area

A

Isa (spatial average intensity)

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7
Q

Refers to time
*with pulsed ultrasound, the transducer is usually receiving (listening), but for brief moments it is transmitting (talking)

A

Temporal

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8
Q

Number of methods of measuring intensity, pulsed waves

A
Four methods,
Itp
Imax or Im
Ipa
Ita
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9
Q

Intensity of the beam at the instant in time of it’s maximal value

A

Itp (temporal peak intensity)

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10
Q

average intensity during the most intense half cycle

A

Imax or Im

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11
Q

average intensity during -the transmit time — is called

A

Ipa (pulse average intensity)

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12
Q

Averaging the intensity during the entire pulse repetition period—both the transmit and receive times— is called

A

Ita (temporal average intensity)

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13
Q

Measured during transmit time only

A

Pulse average intensity

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14
Q

Measured during both the transmit and receive times

A

Temporal average

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15
Q

The highest temporal intensity is _______ and it is slightly higher than ___________

A

Itp and it is slightly higher than Imax

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16
Q

Is lower than Imax, because it includes values over the entire pulse duration, and the tail end of the pulse is less intense than the beginning

A

Ipa (pulse average intensity)

17
Q

The lowest of all temporal intensities is ____________ because it is the only method that includes the receive and transmit time

A

Ita (temporal average intensity)

18
Q

Measured at the location where intensity is maximum, and at the instant in time that the most powerful fart of the pulse passes

A

Isptp (spatial peak/temporal peak)

19
Q

Measured at the location where intensity is maximum, averaged over the transmit time (pulse duration)

A

Isppa (spatial peak/pulse average)

20
Q

Measured at the location where intensity is maximum and averaged over all time, both the transmit and receive times

A

Ispta (spatial peak/temporal average)

21
Q

Measured over the entire cross-sectional area of the sound beam, and over all time

A

Isata (spatial average/temporal average)

22
Q

Temporal intensities From Largest to Smallest

A

Itp (temporal peak)
Imax (average of most intense half cycle)
Ipa (pulse average)
Ita (temporal average)

23
Q

All measurements have units of

24
Q

Six different methods to measure and report intensities. Methods describe the same wave in a variety of ways

A
SPTP (spatial peak/temporal peak)
SATP (spatial average/temporal peak)
SPTA (spatial peak/ temporal average)
SATA (spatial average/temporal average)
SPPA (spatial peak/pulse average)
SAPA (spatial average/pulse average)
25
No independently confirmed significant bioeffects have been confirmed in mammalian tissue below (medical usage)
100W/cm^2
26
Two bioeffects of ultrasound
Heat and cavitation
27
As sound energy is transmitted through tissue, some energy is reflected and some energy is absorbed as
Heat
28
The formation, growth and dynamic behavior of gas bubbles
Cavitation
29
The peak intensity at the point in space where the intensity is the highest, and that occurs when the ultrasonic emitting device is "on" * It is the highest of the measured intensities
SPTP (spatial peak/ temoporal peak
30
The average power output of the device over the pulse repetition period, divided by a reference, usually that of the transducer face * yields the lowest, and more commonly used measures of intensity - most quickly determined & most frequently quited by manufacturers
SATA (spatial average/ temporal average)
31
The peak intensity over a selected area, such as the transducer face, that occurs when the ultrasonic emitting device is "on"
SATP (spatial average/ temporal peak)
32
The maximum spatial intensity when the sound beam is "on" average over the pulse reptition period
SPTA (spatial peak/ temporal average)
33
The pulse averaged intensity measured at the point in space where the value is maximal
SPPA (spatial peak/ pulse average)
34
The pulse average intensity averaged over the beam cross-sectional area of the sound beam, averaged over the transmit time ( pulse duration)
SAPA (spatial average/ pulse average)