Compensation is generally referred to as Time gain compensation or Depth gain compensation.

• A. Time gain compensation
• B. Depth gain compensation
• C. Both A and B
• D. Automatic gain control

Answer: (C)

Compensation in ultrasound means boosting echoes from deeper tissues so the image stays uniformly bright as depth increases. This is done by increasing receiver gain as echoes come back from greater distances. Time gain compensation (TGC) is the term most often used for applying a variable gain as a function of time after transmission, which maps to depth. Depth gain compensation (DGC) is basically the same idea—it's another way to describe depth-dependent gain. Because both describe adjusting gain to counteract attenuation with depth, they are both correct references.

Automatic gain control is a different mechanism that automatically adjusts overall gain to keep the image brightness level in range, not specifically correcting for depth-related attenuation.