Module 1 Review

Question 1

Label the parts

Answer 1

1. Transducer wire
2. Backing layer
3. Crystal
4. Matching layer
5. Insulator ring

Question 2

What type of probe excitation will result when an ultrasound system uses a voltage that resembles the following diagram?

Answer 2

Spike

Question 3

What part of the probe has the function of reducing the reflection of sound thus improving it’s transmission into tissue?

Answer 3

Matching layer

Question 4

T or F. A high transducer is more desirable for doppler application?

Answer 4

True

Question 5

The ratio of the amount of energy contained in a vibrational cycle to the amount of energy lost in that cycle is referred to as the transducer Q? T or F?

Answer 5

True

Question 6

If the frequency of transmitted sound decreases the spatial pulse length decreases? T or F?

Answer 6

False

Question 7

What crystal thickness is required to obtain a resonance frequency of 2 MHz if the propagation speed in the crystal is 4000m/s

Answer 7

1mm

C = 4 mmm/ms
F = 2 MHz
Lambda = 2

CT = 2/1 = 1

Question 8

The damping material in probes results in a shorter transmitted pulse of sound. How does this effect the efficiency and bandwidth of the probe respectively?

Answer 8

Decreased efficiency; wider bandwidth

Question 9

High of the following probe types is considered to be both mechanical and electronic?

Answer 9

Annular array

Question 10

Which of the following values best describes the thickness required to create the resonant frequency of a piezoelectric element?

1. 1/2 lambda
2. 1/3 Lambda
3. 1/4 Lambda
4. 1/8 Lambda

Answer 10

1/2 lambda

Question 11

What is the most common material used as the piezoelectric element in electronic array transducers?

Answer 11

Lead zirconate titanate

Question 12

What acoustic impedance value should the damping material equal to ensure the most efficient transfer of energy in an imaging transducer?

1. Air
2. Skin
3. Crystal
4. Matching layer

Answer 12

Crystal

Question 13

What is the most common material used for damping?

Answer 13

Epoxy resin and tungsten powder

Question 14

An increase in the transducer bandwidth will result in improved axial resolution? T or F ?

Answer 14

True

Question 15

Which of the following represents an equation for spatial pulse length?

1. period x ring down
2. Ring down / frequency
3. Frequency / ring down
4. (Speed of sound / frequency) x ring down

Answer 15

(Speed of sound/ frequency) x ring down

Question 16

A decrease in transducer damping will improve the axial resolution. T or F?

Answer 16

False

Question 17

Which of the following field of view shapes would indicate scanning with a vector probe?

1. Rectangle
2. Trapezoidal
3. Pie shaped
4. Circular

Answer 17

Trapezoidal

Question 18

Which of the following probes would result in a pie shaped display?

1. Linear array
2. Vector array
3. Phased array
4. Annular array

Answer 18

Phased array

Question 19

Which of the following could be used to express Q factor?

1. Resonant frequency / fractional bandwidth
2. Fractional bandwidth / resonant frequency
3. Resonant frequency / bandwidth
4. Bandwidth / resonant frequency

Answer 19

Resonant frequency / bandwidth

Question 20

Which of the following statements is correct?

1. Continuous wave instruments require gating
2. Duplex doppler instruments require two crystals
3. Continuous wave instruments require two crystals
4. Directional doppler can only identify positive shifts

Answer 20

Continuous wave instruments require two crystals

Question 21

What change in the dimensions of the crystal would cause the spatial pulse length it increase?

Answer 21

An increase in thickness

Question 22

Which of the following is a possible outcome if a transducer is subjected to temperatures above the curie temperature?

1. Required to bond the matching layer
2. The randomization of dipoles
3. Improved sensitivity
4. Improved resolution

Answer 22

The randomization of dipoles

Question 23

Which of the following transducer components is responsible for minimizing electrical interference from nearby devices?

1. Housing
2. Tuning coil
3. Insulating ring
4. Electrical shield

Answer 23

Electrical shield

Question 24

Which transducer components is most responsible for reducing the Q factor?

Answer 24

Backing material

Question 25

How is the annular array probe swept to obtain an image?

Answer 25

A motor

Question 26

Which of the following probes would have the most degradation in the far field? 1. Vector array 2. Phased linear array 3. Curved linear array 4. Linear translation device

Answer 26

Curved linear array

Question 27

Which of the following is used to reduce the off axis Beams in an array probe? 1. Delays 2. Phasing 3. Apodization 4. Insulator rings

Answer 27

Apodization

Question 28

The amount of divergence of a sound beam is directly proportional to the size of the sound source. T or F?

Answer 28

False

Question 29

What is the Q factor if the transducer bandwidth is 6 and the centre frequency is 4 MHz?

Answer 29

0.67

Question 30

A high Q transducer is more desirable for doppler applications. TF?

Answer 30

True