ARDMS SPI Transducer Construction and Function 4

Question 1

Dynamic receive focusing in modern array transducers improves lateral resolution by:

Accepted Answer

Continuously adjusting the receive focus as echoes return from increasing depths

Answer

During reception, time delays are updated in real time to focus at the depth from which echoes are currently returning, providing optimum lateral resolution at all depths.

Question 2

A transducer labeled '5-12 MHz' is best described as a:

Accepted Answer

Broad-bandwidth transducer capable of operating across that frequency range

Answer

Modern broadband transducers have wide bandwidths allowing the operator to select or the system to use frequencies across the stated range for different imaging needs.

Question 3

Acoustic impedance (Z) is calculated as the product of:

Accepted Answer

Density and propagation speed

Answer

Z = ρ × c, where ρ is the medium's density and c is the speed of sound in that medium.

Question 4

In a 1.5D array transducer compared to a standard 1D array, the key improvement is:

Accepted Answer

Limited electronic control in the elevation dimension to improve slice-thickness resolution

Answer

A 1.5D array adds a few rows of elements in the elevation direction, allowing limited electronic focusing to reduce slice-thickness artifacts compared to a fixed lens.

Question 5

The phenomenon of pulse ring-down (ringing) in a transducer is reduced by:

Accepted Answer

Using a heavily damped backing layer with high attenuation

Answer

A heavily damped (high-attenuation) backing layer absorbs the residual mechanical energy of the crystal quickly, shortening ring-down and improving axial resolution.

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI Transducer Construction and Function 4