Transducer Construction and Function Flashcards
7 cards from real ARDMS SPI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Transducer Construction and Function flashcards as text
A 2D matrix array transducer differs from a standard phased array primarily in that it:
Answer: Has elements arranged in rows and columns enabling steering in both lateral and elevation planes
A 2D matrix array arranges thousands of elements in a grid, allowing full electronic steering and focusing in both the lateral and elevation dimensions for real-time 3D imaging.
The Curie temperature of a piezoelectric material is important clinically because:
Answer: Above this temperature the material permanently loses its piezoelectric properties
The Curie temperature is the threshold above which the polarization of piezoelectric domains is disrupted, permanently destroying the crystal's piezoelectric behavior.
In harmonic imaging, the transducer transmits at frequency f₀ and receives at:
Answer: 2f₀
Tissue harmonic imaging transmits at the fundamental frequency f₀ and selectively receives the second harmonic at 2f₀, which is generated nonlinearly in tissue.
Which statement about annular array transducers is TRUE?
Answer: They focus symmetrically in all planes but require mechanical steering for scanning
Annular arrays provide symmetric (round) electronic focusing in all planes but cannot steer electronically, requiring mechanical wobbling or rotation to sweep the beam.
Subdicing (dicing grooves cut partway through) of transducer elements is performed primarily to:
Answer: Reduce lateral coupling between elements and improve element flexibility
Subdicing cuts partially through the crystal to reduce mechanical coupling between adjacent elements and allow the element to flex more efficiently, especially for curved arrays.
The effective radiating area (ERA) of a transducer is always:
Answer: Less than its geometric face area
The ERA is the area that actually produces ultrasound energy and is always somewhat less than the total geometric area of the transducer face because edge regions vibrate less effectively.
Which transducer design characteristic MOST directly determines axial resolution?
Answer: Spatial pulse length
Axial resolution equals half the spatial pulse length; shorter pulses (fewer cycles, higher frequency, greater damping) yield better axial resolution.