Ultrasound Transducers 2 Flashcards
Which of the following correctly describes a dedicated continuous wave doppler transducer
A. cork or epoxy for backing material
B. very low duty factor
C. low quality factor
D. narrow bandwidth
D
Which of the following applies to therapeutic ultrasound transducers
A. low Q facor
B. frequencies >15MHz used due to the increased potential for focused cavitation
C. narrow bandwidth
D. backing material at least 2x thickness of that used in imaging transducers
C
What type of transducer array has the fewest number of elements
A. linear phased array
B. curvilinear sequential array
C. mechanical transducer
D. annular array
D
Which of the following occurs with the implementation of backing material in a transducer
A. increased duty factor
B. improved sensitivity
C. higher Q factor
D. shorter pulses
D
Which of the following is correct regarding endocavity probes
A. they most commonly incorporate a curved array of elements that are electronically steered to create an extended field of view
B. they should be cleaned and soaked in a high level disinfectant at least once a day
C. endocavity probes offer improved lateral resolution at greater depths
D. one of the main disadvantages of the tightly curved elements of the endocavity probe is decreased spatial resolution
A
The crystal in the ultrasound transducer converts
A. electrical energy into mechanical energy
B. mechanical energy into heat energy
C. electrical energy into heat energy
D/ mechanical energy into sound energy
A
Transducers can be electronically focused by
A. varying timing of the release of the pulses
B. adding an acoustic lens to the face of the transducer
C. using a convex shaped PE element
D. using a concave shaped element
A
When scanning the thyroid, you change from a 5MHz probe to a 10MHz probe. Which of the following statements is true
A. there will be decreased attenuation with increased penetration with the 10MHz probe
B. the 2D imaging depth settings are much more limited in the 5MHz transducer
C. the reflected waves will be more quickly received and processed by the 10MHz probe
D. the spatial resolution will improve with the 10MHz transducer
D
Which of the following statements correctly describes annular arrays
A. an annular array can electronically focus the beam
B. an annular array can use phasing to electronically steer the beam
C. annular arrays provide the lowest slice thickness resolution
D. annular arrays usually contain 30 or more circular elements
A
Some US transducer arrays allow you to reduce the thickness of the beam as an additional type of focusing. What effect will this change have on the image
A. decreased beam attenuation
B. improved contrast resolution
C. improved elevational resolution
D. degraded temporal resolution
C
Transducers can be electronically focused by
A. varying timing of the release of the pulses
B. adding an acoustic lens to the face of the transducer
C. using a concave shaped PE element
D. using a concave shaped element
A
To obtain a longer near zone
A. add a lens to the transducer face
B. change from a 3MHz to a 6MHz transducer
C. decrease the transducer element diameter
D. use a linear transducer instead of a curved transducer
B
The damping material causes a ______ bandwidth and a ______ quality factor
A. wider, hugher
B. narrower, lower
C. wider, lower
D. narrower, higher
C
Which of the following is true regarding annular arrays and linear arrays
A. annular arrays have multiple elements, linear arrays have a single element
B. annular arrays must be mechanically steered, linear arrays use electronic steering
C. annular arrays and linear arrays can be electronically steered
D. annular arrays can be electronically steered, linear arrays must be mechanically steered
B
Mirrors and lenses can be used to
A. improve sound transmission into the body
B. electronically focus the US beam
C. mechanically docus the US beam
D. increase the PRF of the transducer
C
