Module 1 Review Flashcards
Label the parts
- Transducer wire
- Backing layer
- Crystal
- Matching layer
- Insulator ring
What type of probe excitation will result when an ultrasound system uses a voltage that resembles the following diagram?
Spike
What part of the probe has the function of reducing the reflection of sound thus improving it’s transmission into tissue?
Matching layer
T or F. A high transducer is more desirable for doppler application?
True
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?
True
If the frequency of transmitted sound decreases the spatial pulse length decreases? T or F?
False
What crystal thickness is required to obtain a resonance frequency of 2 MHz if the propagation speed in the crystal is 4000m/s
1mm
C = 4 mmm/ms
F = 2 MHz
Lambda = 2
CT = 2/1 = 1
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?
Decreased efficiency; wider bandwidth
High of the following probe types is considered to be both mechanical and electronic?
Annular array
Which of the following values best describes the thickness required to create the resonant frequency of a piezoelectric element?
- 1/2 lambda
- 1/3 Lambda
- 1/4 Lambda
- 1/8 Lambda
1/2 lambda
What is the most common material used as the piezoelectric element in electronic array transducers?
Lead zirconate titanate
What acoustic impedance value should the damping material equal to ensure the most efficient transfer of energy in an imaging transducer?
- Air
- Skin
- Crystal
- Matching layer
Crystal
What is the most common material used for damping?
Epoxy resin and tungsten powder
An increase in the transducer bandwidth will result in improved axial resolution? T or F ?
True
Which of the following represents an equation for spatial pulse length?
- period x ring down
- Ring down / frequency
- Frequency / ring down
- (Speed of sound / frequency) x ring down
(Speed of sound/ frequency) x ring down
A decrease in transducer damping will improve the axial resolution. T or F?
False
Which of the following field of view shapes would indicate scanning with a vector probe?
- Rectangle
- Trapezoidal
- Pie shaped
- Circular
Trapezoidal
Which of the following probes would result in a pie shaped display?
- Linear array
- Vector array
- Phased array
- Annular array
Phased array
Which of the following could be used to express Q factor?
- Resonant frequency / fractional bandwidth
- Fractional bandwidth / resonant frequency
- Resonant frequency / bandwidth
- Bandwidth / resonant frequency
Resonant frequency / bandwidth
Which of the following statements is correct?
- Continuous wave instruments require gating
- Duplex doppler instruments require two crystals
- Continuous wave instruments require two crystals
- Directional doppler can only identify positive shifts
Continuous wave instruments require two crystals
What change in the dimensions of the crystal would cause the spatial pulse length it increase?
An increase in thickness
Which of the following is a possible outcome if a transducer is subjected to temperatures above the curie temperature?
- Required to bond the matching layer
- The randomization of dipoles
- Improved sensitivity
- Improved resolution
The randomization of dipoles
Which of the following transducer components is responsible for minimizing electrical interference from nearby devices?
- Housing
- Tuning coil
- Insulating ring
- Electrical shield
Electrical shield
Which transducer components is most responsible for reducing the Q factor?
Backing material
How is the annular array probe swept to obtain an image?
A motor
Which of the following probes would have the most degradation in the far field?
- Vector array
- Phased linear array
- Curved linear array
- Linear translation device
Curved linear array
Which of the following is used to reduce the off axis Beams in an array probe?
- Delays
- Phasing
- Apodization
- Insulator rings
Apodization
The amount of divergence of a sound beam is directly proportional to the size of the sound source. T or F?
False
What is the Q factor if the transducer bandwidth is 6 and the centre frequency is 4 MHz?
0.67
A high Q transducer is more desirable for doppler applications. TF?
True
