Lecture 2 Flashcards

1
Q

Diagnostic ultrasound systems are ______ systems

A

Pulse echo

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2
Q

Diagnostic ultrasound systems determines

A

Echo strength and location of echo generating sites

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3
Q

Echo strencth is shown by

A

Brightness

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4
Q

Location of object is determined by

A

Arrival time and direction of returning echoes

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5
Q

The ultrasound instrument consists of 4 main section s

A

Beam former
Signal processor
Image processor
Display

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6
Q

What is the beam former

A

Where it all begins

Works with the transducer

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7
Q

Are we working with sound or voltage at the beam former

A

Voltage

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8
Q

Instruments of beam former

A
Master syncronizer 
Pulser 
Pulse delays
Transmit/recieve switch 
Amplifiers 
Analog-to-diigital converters 
Echo delays 
Summer
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9
Q

Beam former involves _______ and ______. It is divided into these 2 channels

A

Transmission and reception

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10
Q

Each path to each individual element is a

A

Transmission channel

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11
Q

Each path from each individual element is a.

A

Reception channel

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12
Q

Components of transmitter (4)

A

Master synchronizer
Pulser
Pulse delays
Transmit/recieve switch

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13
Q

Components of receiver (4)

A

Amplifier
Analog-to-digital
Echo delays
Summer

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14
Q

What does the master synchronizer do (4)

A

Coordinates the entire system
Tells the pulser when to fire
Transmission/ receiver functions
Waits for echo to come back before firing the next pulse

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15
Q

Why does the master synchronizer wait for the echo to come back before firing the next pulse

A

Prevents range abuguity artifacct

This is the incorrect placement of echo along scan line

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16
Q

What does the pulser do

A

Produces electric voltages that drive the transducer

17
Q

Pulser is ____ cycle of voltage of desired ______

A

Single

Frequency

18
Q

What is the to the electric voltage sent from the pulser?

A

The transducer produces ultrasound pulse

19
Q

What is the fundamental frequency eequal to

A

Resonance=operating= transmit freq

20
Q

Fundamental frequency ranges from ___-____ MHz

21
Q

PRFvoltage of the pulse is equal to _______ becuase

A

PRF pulse

Becuase for each pulse one US pulse is generated

22
Q

PRPvoltage of pulser =

23
Q

Unit for frequency of pulser

24
Q

Unit for PRF of pulser

25
Typical values of PRF in greyscale 2D
4-15kHz
26
Typical values of PRF in doppler
5-30
27
PRF is operator control in
doppler
28
In greyscale imaging PRF is
Automatic Depth of image will determine PRF (indirect control)
29
PRF is limited by
Depths
30
PRF is always less than
77kHz
31
All echoes from one pulse must be recieved before
The next pulse is emitted
32
Three qualities of deeper images
Echoes take longer to return PRF is decreased Frame rate is decreased
33
Instrument automatically achieves _____ PRF
Highest
34
The power or strength of the beam entering the tissue is closely related to
Intensity
35
Stronger the voltage= stronger
Pulse
36
What happens if we go over 77cm/ms
We would get echo misplacement/range ambuguity artifact
37
What happens to the PRF in 2D if the depth is increased by 4X
It will decrease by 4X
38
Pulser can be controlled by
Output dial on some machine Displayed in dB/%