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Ultrasound Physics > Ch 14: Pulsed Echo Instrumentation > Flashcards

Ch 14: Pulsed Echo Instrumentation Flashcards

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1
Q

What are the two major functions of the u/s system?

A
  1. preparation and transmission

2. reception

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2
Q

This u/s component transforms electrical energy into acoustic energy. During reception it converts the returning acoustic energy into electrical energy.

A

transducer

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3
Q

The u/s component creates and controls the electrical signals sent to the transducer that generates sound pulses.

A

pulser and beam former

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4
Q

The u/s component determines the amplitude, pulse repetition period, and pulse repetition frequency.

A

pulser

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5
Q

This u/s component determines the firing delay patterns for phased array systems.

A

beam former

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6
Q

This u/s component transforms the electrical signals from the transducer into a form suitable for display.

A

receiver

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7
Q

This u/s component presents processed data.

A

display

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8
Q

This u/s component archives the u/s studies.

A

storage

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9
Q

This u/s component maintains and organizes the proper timing and interaction of the system’s components.

A

master synchronizer

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10
Q

T/F? The pulser functions during reception.

A

FALSE, during transmission

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11
Q

Synonyms for pulser voltage?

A
  1. output gain
  2. acoustic power
  3. pulser power
  4. energy output
  5. transmitter output
  6. power
  7. gain
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12
Q

Is the pulser voltage adjustable by the sonographer?

A

yes

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13
Q

Can output power alone make an image of uniform brightness from top to bottom?

A

nope

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14
Q

This is loosely defined as a random and persistent disturbance that obscures or reduces a signal’s clarity.

A

noise

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15
Q

This is a comparison of the meaningful information in an image compared to the amount of contamination.

A

signal-to-noise ratio

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16
Q

When the signal-to-noise ratio is high, the signal is much ___ than the noise and the image is of ___ quality.

A

stronger, high

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17
Q

When the signal-to-noise ratio is low, the signal is much ___ and the image is of ___ quality.

A

lower, low

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18
Q

How does transducer output affect noise?

A

Increasing power output also increases signal-to-noise ratio.

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19
Q

The ___ determines the time between one voltage spike and the next (PRP).

A

pulser

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20
Q

The beam former adjusts electrical spike voltages to reduce lobe artifacts in a process called…

A

apodization

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21
Q

Modern beam formers use advanced microprocessor technology called a…

A

digital beam former.

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22
Q

What are the advantages of a digital beam former?

A
  1. softward programming
  2. extremely stable
  3. versatile
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23
Q

The ___ protects the receiver components from the signals that are created for pulse transmission and directs the electrical signals from the transducer to the appropriate electronic and processing components.

A

switch

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24
Q

The ___ prepares the information contained in minuscule signals for eventual display on the system’s monitor.

A

receiver

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25
Q

What is the order of receiver operations?

A
  1. amplification
  2. compensation
  3. compression
  4. demodulation
  5. reject
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26
Q

During ___, each electronic signal returning from the transducer is made larger.

A

amplification

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27
Q

T/F? Each signal undergoes an equal amount of amplification.

A

true

28
Q

T/F? Amplication alone can make an image of uniform brightness from top to bottom.

A

FALSE, cannot

29
Q

Is amplification adjustable by the sonographer?

A

yes

30
Q

Amplification is measured in units of…

A

decibels (dB)

31
Q

What’s a typical value for amplification?

A

60-100 dB

32
Q

This is the process of improving the quality of a signal before it is amplified.

A

preamplification

33
Q

Preamplification occurs where?

A

in the transducer itself

34
Q

The receiver corrects for attenuation with a process called…

A

compensation

35
Q

T/F? Compensation creates an image that is uniformly bright from top to bottom.

A

true

36
Q

Is compensation adjustable by the sonographer?

A

yes

37
Q

Synonyms for compensation?

A
  1. time-gain compensation (TGC)
  2. depth gain compensation (DGC)
  3. swept gain
38
Q

The depth at which variable compensation begins is known as the….

A

delay.

39
Q

Compensation corrects for the effects of increasing attenuation that result from increasing path length in the region of the…

A

slope.

40
Q

Reflections are maximally compensated by the u/s at the region of the…

A

knee.

41
Q

This region indicates the maximum amount of compensation that the receiver can provide.

A

far gain

42
Q

T/F? Compression is performed twice.

A

true

43
Q

This keeps the electrical signal levels within the accuracy range of the system.

A

compression

44
Q

This keeps an image’s gray scale content within the range of detection by the human eye.

A

compression

45
Q

Is compression adjustable by the sonographer?

A

yes

46
Q

Synonyms of compression?

A

log compression, dynamic range

47
Q

Compression is reported in units of…

A

decibels (dB)

48
Q

This is a two-part process that changes the electrical signals within the receiver into a form more sutiable for display ona monitor.

A

demodulation

49
Q

This converts all negative voltages into positive voltages.

A

rectification

50
Q

This places a smooth line around the ‘bumps’ and evens them out.

A

smoothing or enveloping

51
Q

Is demodulation adjustable by the sonographer?

A

nope

52
Q

How does demodulation effect the image?

A

Trick question! It doesn’t.

53
Q

This allows the sonographer to control whether low-level gray scale information within the data will appear on the displayed image.

A

reject

54
Q

Synonyms for reject?

A

threshold or suppression

55
Q

Is reject adjustable by the sonographer?

A

yes

56
Q

How does reject effect the image?

A

It effects only low-levels echoes, not bright echoes.

57
Q

Systems with ___ use only the high frequency part of the reflected pulse’s bandwidth to create the superficial portion of the image.

A

dynamic frequency tuning

58
Q

This affects image brightness by altering the strength of the sound pulse that the transducer sends to the body.

A

output power

59
Q

Increasing output power improves the ___ because the meaningful diagnostic echoes become stronger while the noise level remains unchanged.

A

signal-to-noise ratio

60
Q

This alters the strength of the voltages in the receiver that the transducer created during reception.

A

receiver gain (amplification)

61
Q

T/F? Increasing amplification does not alter the signal-to-noise ratio.

A

true, both signals and noise are treated identically

62
Q

Patient exposure to sound energy is affected by alteration in ___ but not by changes in ___.

A

output power, amplification

63
Q

ALARA stands for…

A

As Low As Reasonably Achievable

64
Q

If the image is too dark, first increase the ___ which does no increase patient exposure.

A

receiver gain

65
Q

If the image is too bright, first decrease the ___ which decreases patient exposure.

A

output power

Ultrasound Physics (23 decks)

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