Ultrasound Knobology

Greetings Scan Squad! 

It’s time to review everyone’s favourite (insert intense sarcasm) topic…machine control settings, also known as knobology! 

Many vets don’t take the time to learn what these dials do because, quite simply, it’s a pretty boring topic! Yet, image quality is one of the biggest gripes I hear when talking to vets about their ultrasounds. 

You need to master these few controls to give you the best images possible! 

So here’s a quick, straightforward explanation:

1. Gain = overall image brightness -> overall gain: uniform amplification
   

2. Time Gain Compensation (TGC) = image brightness at different depths -> adjusted gain: balanced amplification (selectively alters the gain at different depths)
   

3. Depth = how many centimetres of image you see (keep the structure of interest in the middle third of the screen)

4. Focal Zone = obtains the best resolution (place at or slightly below the region of interest)

Pro tip: these controls are not a ‘set once and forget’. I constantly have my hand on these throughout a scan and alter them continuously to obtain the best image.

1. Gain

2. TGC

3. Depth

4. Focal Zone

Happy scanning!