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ULTRASOUND PHYSICS > Chapters 4&5 > Flashcards

Chapters 4&5 Flashcards

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1
Q

Pulses used for diagnostic ultrasound are usually _________ cycles long. (Consider gray scale and color)

A

Grey scale 2-3 cycles
Color 3-30 cycles

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2
Q

Spatial Pulse Length (SPL) is the product of
a. velocity and PRP
b. frequency and period
c. propagation speed and PRF
d. wavelength and cycles per pulse
e. wavelength and velocity​

A

D

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3
Q

SPL is determined by
a. Source and medium
b. Medium only
c. Source only
d. Propagation speed
e. Transducer only

A

A

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4
Q

Spatial pulse length is
a. Frequency X wavelength
b. PRF X wavelength
c. Wavelength X number of cycles in pulse
d. Duty factor multiplied by wavelength

A

C

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5
Q

What happens to SPL if depth of view increases using the same transducer?
a. Increases
b. Decreases
c. Remains the same
d. Does not change until sonographer adjusts it

A

C

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6
Q

If frequency increases, the spatial pulse length
a. Increases
b. Decreases
c. Does not change
d. Depends on depth of view

A

B

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7
Q

Pulse A is from a 5 MHz transducer and pulse B is from a 10 MHz transducer. Both pulses have 4 cycles per pulse.
a. Pulse A will have greater SPL
b. Pulse B will have greater SPL
c. Both pulses will have the same SPL
d. It depends on the PRF

A

A

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8
Q

If you increase the depth of view from 2 cm to 3 cm, the SPL
a. Increases
b. Decreases
c. Does not change
d. Depends on the PRF

A

C

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9
Q

Which pulse has a longer spatial pulse length?
a. from a 10 MHz probe
b. from a 1 MHz probe
c. they are the same
d. cannot be determined

A

D

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10
Q

PRP is defined as
a. The product of wavelength and propagation speed
b. The reciprocal of frequency
c. The pulse transmit or “on” time plus the pulse listening or “off” time
d. The time the pulse is transmission

A

C

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11
Q

The number of pulses occurring in 1 sec is called the
a. Pulse repetition period
b. Pulse repetition frequency
c. Spatial pulse length
d. Pulse duration
e. Duty factor

A

B

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12
Q

Two waves can have identical Pulse Repetition Frequencies, even if their frequencies are different.
a. True​​
b. False

A

A

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13
Q

When you change the PRF you are changing
a. The number of cycles in the pulse
b. The number of pulses per second
c. The number of wavelengths per pulse
d. The amplitude of the cycles in the pulse

A

B

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14
Q

The range of PRF used in diagnostic ultrasound is
a. 0.5 to 4 kHz
b. 1 to 10 kHz
c. 1 to 7 kHz
d. 10-15 MHz

A

B

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15
Q

PRP and PRF can be changed by
a. increasing duty factor
b. decreasing spatial pulse length
c. altering depth of view
d. increasing the period

A

C

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16
Q

If the depth of view increases, the PRF
a. Increases
b. Decreases
c. Changes only if the transducer is changed
d. Remains the same

A

B

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17
Q

If the PRF increases, the PRP
a. Increases
b. Decreases
c. Changes only if the transducer is changed
d. Is not affected

A

B

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18
Q

Pulse Repetition Period is the reciprocal of Pulse Duration
a. True​
b. False

A

B

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19
Q

The PRF of a 5 MHz transducer is greater than the PRF of a 2.5 MHz transducer.
a. True ​
b. False

A

A

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20
Q

PRF depends on
a. Source of the sound wave/transducer
b. The propagation speed
c. The time gain compensation
d. The wavelength

A

A

21
Q

What is the formula for Duty Factor? _______________________

A

DF= PD/PRP • 100

22
Q

What is the value of the duty cycle for continuous wave (CW) U/S?
a. 100 %
b. 1 %
c. Depends on the frequency of the wave
d. CW U/S does not have a duty factor

A

A

23
Q

In pulsed ultrasound, the maximum value of the duty factor is
a. 100 %
b. 1 %
c. Less than 100%

A

C

24
Q

Duty factor depends on the frequency of the transducer
a. true​​
b. false

A

B

25
Q

Duty factor is determined by
a. The sonographer
b. The transducer only
c. The depth of view
d. The propagation speed

A

B

26
Q

If the PRF decreases, the duty factor
a. Decreases
b. Increases
c. Is not changed
d. Depends on the propagation speed

A

A

27
Q

When the spatial pulse length increases, the duty factor
a. Decreases
b. Increases
c. Is not changed
d. They are not related

A

B

28
Q

Two pulses are created by different transducers and both have the same frequency, the pulse containing more cycles has
a. Lower PRF
b. Shorter pulse duration
c. Longer pulse duration
d. Longer PRP

A

C

29
Q

Duty factor can be changed by the sonographer.
a. True
b. False

A

A

30
Q

The units for duty factor are
a. Decibels
b. Watts
c. microseconds
d. A ratio without units

A

D

31
Q

In continuous wave ultrasound, which of the following are the same?
a. SPTA
b. SAPA
c. SATA
d. SPTP

A

B&C

32
Q

Which is the highest intensity?
a. SPTP
b. SPTA
c. SATP
d. SATA

A

A

33
Q

What are the units of intensity?
a. Watts
b. decibels
c. watts/cm squared
d. Hz

A

C

34
Q

Intensity is equal to
a. Power/ area
b. Area/power
c. Amplitude/distance
d. Power in decibels

A

A

35
Q

Intensities are important because
a. Of overheating in the transducer
b. Bioeffects on the tissue being scanned
c. Efficient use of the power of the scanner

A

B

36
Q

Temporal intensity is
a. The beam intensity during the transmitting time
b. The beam intensity across the area being scanned
c. The intensity compared to the duty factor

A

A

37
Q

Spatial intensity is
a. The beam intensity during the transmitting time
b. The beam intensity across the area being scanned
c. The intensity compared to the duty factor

A

B

38
Q

The beam uniformity coefficient describes
a. The SPTP
b. The spread of a beam in space (SP/SA factor)
c. A unitless ratio of bioeffects

A

B

39
Q

The spatial intensity is usually highest at
a. The center of the beam
b. The circumference of the beam
c. A strip across the diameter of the beam
d. The same across the width of the beam

A

A

40
Q

Which of the following will results in a decrease in beam intensity?
a. Increasing amplitude
b. Increasing output power
c. Decreasing receiver gain
d. Increasing beam area

A

D

41
Q

Power divided by beam areas is equal to
a. Propagation speed
b. Intensity
c. Amplitude
d. Fundamental frequency

A

B

42
Q

Pulse duration is equal to
a. Frequency X period
b. Period X wavelength
c. Number of cycles in pulse divided by wavelength
d. Period X number of cycles in pulse

A

D

43
Q

Pulse duration is determined by
a. Source
b. Medium
c. Both source and medium
d. Sonographer

A

A

44
Q

A sonographer can adjust the duration of an acoustic pulse since it depends on the maximum imaging depth.
a. True​
b. False

A

B

45
Q

The units of pulse duration are units of
a. Time
b. Frequency
c. Distance
d. Number
e. Volume

A

A

46
Q

If the depth of view increases, the pulse duration
a. Increases
b. Decreases
c. Remains unchanged
d. Depends on the transducer frequency

A

C

47
Q

Pulses from a 2.5 MHz transducer and a 5 MHz transducer each have 3 cycles per pulse. The pulse from the 2.5 MHz transducer has
a. A lower PRF
b. A higher Pulse repetition period
c. A shorter pulse duration
d. A longer pulse duration

A

D

48
Q

A sonographer can adjust the pulse duration by
a. Changing the angle of the transducer
b. Increasing the gain
c. Reducing the image depth
d. Increasing the PRF
e. None of the above

A

E

49
Q

Which of the following is determined by both source and medium?
a. frequency
b. period
c. propagation speed
d. wavelength

A

D

ULTRASOUND PHYSICS (7 decks)

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