1-5
The ability of an ultrasound machine to detect tiny reflected sound waves refers to:
Sensitivity
True or False? A resonant frequency is associated with a wide bandwidth.
False
What action is appropriate for ultrasound transducers?
Disinfection
Greater impedance differences are associated with:
Greater reflections
The impedance of a transducer active element is 1,800,000 Rayls, and the impedance of the skin is 1,500,000 Rayls. What is an acceptable impedance for the matching layer?
1,726,000 Rayls
Which of the following characteristics is associated with Backing Material?
Vast difference of impedance when compared to the PZT
Long pulses
High degree of sound absorption
Increases transducer sensitivity
High degree of sound absorption
Which wave has the highest Q factor? (Image)
A
What portion of the transducer increases the efficiency of sound energy transfer between the active element and the body?
Matching layer
You are asked to fabricate a pulsed ultrasound transducer with the lowest possible frequency. Which piezoelectric crystal would you select?
6 mm thick, 4 cm diameter, 4.0 mm/μs propagation speed
4 mm thick, 9 cm diameter, 5.0 mm/μs propagation speed
2 mm thick, 6 cm diameter, 6.0 mm/μs propagation speed
8 mm thick, 2 cm diameter, 2.0 mm/μs propagation speed
8 mm thick, 2 cm diameter, 2.0 mm/μs propagation speed
What is the relationship between Quality Factor and Bandwidth?
Inversely
The following equation calculates: Sound's speed in PZT (mm/μs)/ 2 x thickness (mm)
Pulsed wave frequency
Which wave has the highest frequency? (Image)
C
What is the purpose of the backing material in the transducer assembly?
Reduce the number of cycles in a pulse
During transducer reception, _____ (is/are) converted into _____.
Sound, electricity
The cylindrical tube that protects the internal components of the transducer from damage is:
Case
What determines pulsed wave transducer frequencies?
Both, speed of sound and thickness of the PZT
On each wave, the red arrow can represent the: (Image)
Period
Which of the following terms can't be used to describe the PZT?
Crystal
Ceramic
Motor
Active element
Motor
Which of the following lists orders the impedance from the highest to lowest?
PZT, gel, matching layer, skin
Skin, gel, matching layer, PZT
PZT, matching layer, gel, skin
Gel, PZT, matching layer, skin
PZT, matching layer, gel, skin
At what thickness is the PZT crystal of a 3 MHz pulsed wave transducer?
One-half of the wavelength of the sound wave in the PZT
Exceeding the Curie point of a transducer element will result in:
Loss of all piezoelectric properties
What is the frequency of sound from a continuous wave transducer when the transmitter creates a 5 MHz electrical signal?
5 MHz
The range of frequencies in a pulse is the:
Bandwidth
A transducer has a main frequency of 5 MHz. However, the pulse contains acoustic energy with frequencies as low as 3.5 MHz and as high as 7.0 MHz. What is the bandwidth of the transducer?
3.5 MHz
If the pulse repetition frequency is increased, how will the pulsed wave transducer frequency change?
It will remain unchanged