What measures the output of a transducer?

• A. Hydrophone
• B. Receiver
• C. Display
• D. Hydrometer

Answer: (A)

The key idea is that the device used to quantify the transducer’s acoustic output is a hydrophone. A hydrophone is a small sensor designed to work in fluids and converts the acoustic pressure variations produced by the transducer into an electrical signal that can be measured and analyzed. This allows us to determine parameters of the transducer’s output, such as pressure amplitudes and waveform, independent of the imaging system. The other devices aren’t suited for this purpose: a receiver is part of the system that detects echoes after tissue interaction, not the transducer’s own emission; a display only shows results from other processing; a hydrometer measures liquid density and has no role in ultrasound output measurement.