6: Manipulating Images
EVO User Manual
69
©2018 E.I. Medical Imaging
6: Manipulating Images
Manipulate images by adjusting the Gain settings. The Gain controls
compensate for the reduction in sound amplitude as it travels into tissue. The
Gain controls can intensify the returning signals and display images brighter and
more visible on the screen. You can adjust the Gain for the near field (higher), far
field (lower), or the entire field (overall gain). Excessive increase in Gain will add
noise to the image. For optimal diagnostic images, adjust the Gain to produce
uniform gray scale responses.
About Gain Controls
To view all of the Gain settings on one screen, press Gain (F6) from the home
menu.
Overall GAIN
To adjust the overall gain, use the GAIN key. You can increase/decrease the brightness of the
entire field.
Near Gain
The NEAR Gain control is used to lighten or darken the intensity of the echoes in the near field of
the image (the area closet to the transducer).
Far Gain
The FAR gain control is used to make adjustments to the electronic amplification of the echoes in
the image area that are farthest away (far field) from the transducer.
Time Gain
Compensation
(TGC)
TGC refers to the time taken for an echo to travel from the transducer to the target area. As the
ultrasound signal travels further into the tissue, more and more of its energy is absorbed causing
the echoes to decrease in strength. Therefore, at greater depths, the TGC needs to be set at a
higher setting. Conversely, at a short distance, for example near the skin line, there is more energy
level available and therefore the TGC can be run at nearly a minimum setting.
The EVO offers 8 TGC settings. Adjust these using the touchpad.
