Time Gain Compensation
Time gain compensation (TGC) usually consists of a number of sliders/paddles that correspond to specific depths within the patient (Fig 1).
TGC is used to compensate for increasing attenuation by increasing amplification of the return signal with depth.
On the smaller hand-held systems, TGC is often replaced by independent near and far gain controls (Fig 2).
The operator should aim for an image where similar structures appear at the same brightness level, regardless of depth.
