Week 14 pulsed Echo Instrumentation part 1

Question 1

What does a Pulser do?

Answer 1

Creates the electrical singal that excites the PZT.

Question 2

What does a pulser determine?

Answer 2

The amount of power going into a patient.

Question 3

When does the Pulser function?

Answer 3

During transmission

Question 4

What happens when the pulser is set to a low voltage?

Answer 4

The reflected echoes are weak and the entire image tends to be dark.

Question 5

What happens when the pulser is set to a high voltage?

Answer 5

The reflected echoes are stronger and the entire image is brighter.

Question 6

What does the pulser impact?

Answer 6

output power

Question 7

What does the Pulser control?

Answer 7

1. Amplitude
2. PRP
   3.PRF

Question 8

What is the beam former?

Answer 8

Creates and determines the delay pattern for array transducers.
steering (sloped)
Focus ( curved)

Question 9

What is the Thermal Index?

Answer 9

The thermal index determines how much heating there is in the tissue.

Question 10

What is Mechanical Index?

Answer 10

Measures changes to the energy around the cells that are being imaged. (Cavitation)

Question 11

Are Ti and Mi adjustable?

Answer 11

Yes

Question 12

What is the acceptable voltage range that is able to be sent into the body?

Answer 12

0-100 volts

Question 13

What does ALARA stand for

Answer 13

As
Low
As
Reasonably
Possible

Question 14

What does increased output power create?

Answer 14

increased Ti and Mi

Question 15

What does the beam Former control?

Answer 15

Apodization

Question 16

What does a signal refer to?

Answer 16

Meaningful reflections returned to the transducer.

Question 17

What happens to the output power if the signal to noise ratio is increased?

Answer 17

output power increases, making noise less significant.

Question 18

What is the signal-to-noise ratio?

Answer 18

a comparison of the meaningful information (signal) in an image, compared to the amount of contamination (noise).

Question 19

When the signal-to-noise ratio is high, what happens to the image quality?

Answer 19

the signal is stronger than the noise and the image quality is higher.

Question 20

What happens to image when the signal to noise ratio is low?

Answer 20

The strength of the signal is closer to the signal of the noise, degrading image quality.

Question 21

How does transducer output affect noise?

Answer 21

As output power increases, the signal-to-noise ratio also increases.

Question 22

What is apodization?

Answer 22

When the beam former adjusts electrical spike voltages to reduce lobe artifacts.

Question 23

What are the functions of the pulser?

Answer 23

determines PRP, PRF and amplitude of the outgoing signal

Question 24

The beam former determines the

Answer 24

firing delay patterns of phased array systems

Question 25

What is needed to create a display on the US system?

Answer 25

scan converter

Question 26

When a pulser is set to a low voltage

Answer 26

the active element vibrates gently

Question 27

The big advantage to lower pulser voltages

Answer 27

minimize patient exposure

Question 28

A great advantage of high output power:

Answer 28

improved signal to noise ratio

Question 29

How does transducer output power affect noise?

Answer 29

power increases-signal dominates the image, noise disappears

Question 30

What is the most common way to improve signal to noise ratio?

Answer 30

Increase output power

Question 31

What US machine control determines the time between one voltage spike and the next?

Answer 31

Pulser

Question 32

Why are lower pulser voltages desirable?

Answer 32

decrease transmitted acoustic energy
minimize patient’s exposure to ultrasound energy
minimize likelihood of bioeffects

Question 33

What sets the rate of the pulser & pulse delays?

Answer 33

PRF