ARDMS Ultrasound Physics & Instrumentation Practice Exam 2026 - Free Ultrasound Practice Questions and Study Guide

Auto-gain control (AGC) plays a vital role in ultrasound technology by automatically adjusting the gain based on the strength of the returning echoes. As sound waves travel through tissues and reflect back to the transducer, different tissues will return echoes of varying strengths. The purpose of auto-gain control is to provide a consistent level of image brightness despite these variations, helping to ensure that the features of the imaged structures are visible.

When the echoes arrive back at the transducer, those that are stronger will be adjusted down, whereas weaker echoes will be amplified. This dynamic adjustment is crucial for producing clear and diagnostic images, as it compensates for the differences in tissue echogenicity.

The other choices do not accurately define the function of auto-gain control. Manual adjustments of gain for each frame do not fall under AGC's automated capabilities. Eliminating low-frequency signals or enhancing image brightness manually does not describe the auto-adjusting nature of how AGC operates; instead, AGC functions autonomously to optimize image quality based on the input it receives.