Gain and Depth

Gain and depth are buttons/knobs/selections on all systems. Turn to the right increases; to the left decreases

Gain (Figure 1)

  • Gain increases or decreases white value
  • Similar to turning up the volume when listening to music
  • Set so that fluid is black
  • Over gain can make it difficult to see boarders/interfaces
  • Time Gain Compensation (TCG) allows setting different gains at different depths, and is especially useful in cardiac imaging

Depth (Figure 2)

  • Setting the depth adjusts the size of object images
  • Hash marks along the side are usually set a 1 cm
  • Adjust the Depth to optimize the image
  • Only see the area of interest


  • Most systems have an auto-optimize button which can be helpful
  • Most systems have an auto-optimize button which can be helpful
  • Set the gain and depth in 2D. However, it will affect all imaging (M-mode, Doppler)
  • When first scanning play with the depth and gain so you understand then play with the auto scan
  • It does not improve every image
  • As you get more experienced get in the habit of optimizing every image
  • Selecting 2D will reset back to defaults for that exam type, and this is useful if you can’t figure out how to get back to a good image


Figure 1 - Gain

Figure 2 - Depth


Chan, Vincent, and Anahi Perlas. “Basics of ultrasound imaging.” Atlas of ultrasound-guided procedures in interventional pain management. Springer, New York, NY, 2011. 13-19.