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:
- Gain = overall image brightness -> overall gain: uniform amplification
- Time Gain Compensation (TGC) = image brightness at different depths -> adjusted gain: balanced amplification (selectively alters the gain at different depths)
- Depth = how many centimetres of image you see (keep the structure of interest in the middle third of the screen)
- 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.
- Gain
- TGC
- Depth
- Focal Zone
About Belinda
Dr. Belinda Carey is a veterinarian, educator and founder of eVet Academy, with a passion for making veterinary ultrasound practical and accessible. After graduating with first-class honours and earning her MANZCVS in Small Animal Internal Medicine, Belinda spent years providing mobile ultrasound services to general practice clinics, where she recognised a widespread need for practical, step-by-step ultrasound training.
Combining her veterinary expertise with her teaching background, she created eVet Academy to help small animal vets build confidence and improve their scanning skills through clear, clinically relevant education designed for everyday practice.
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