It is difficult enough to hold a probe and manipulate it to create an image, its even harder when it’s a bar of soap! One thing that makes this happen when you are learning is layering piles and piles of gel on the skin and the ultrasound probe. This invariably leads to a monumental mess, and a very slippery probe which is difficult to handle.

But how much gel is too much gel? Well, there is no hard and fast rule.

First of all, lets consider for a moment what the gel is actually doing, what purpose does it serve?

The gel acts a coupling agent to assist with transmission of the sound waves from the ultrasound probe into the superficial tissues.  This helps you achieve the best possible image as more energy is being transmitted into the tissues and reflected back to the probe for processing.

Are there different types of gel?

There are two main types of ultrasound gel – Non-sterile and sterile. For all diagnostic scans that are not invasive , non sterile gel can be used as you are superficial to the bodys natural barrier, the skin.

Do we different amounts of gel for different regions?

It is worth noting however that different anatomical regions will require different amounts of gel. We want to ensure the probe face is in contact with as much of the tissue as possible. This is difficult in some regions where the bony anatomy creates many difficult surfaces eg around the lateral malleoli visualising the peroneal tendons. In comparison, when visualising muscles in the calf region, there will likely be better probe contact, and so less gel may be required.

How else can we use gel to assist our techniques?

Another way that ultrasound gel can be used is when performing injections. Sometimes, accessing a joint can be challenging especially if there is limited range of movement or degenerative changes such as Osteophytes, narrowing the joint. The use of sterile gel, note this is strictly sterile gel, can assist and create an easier angle. Sterile gel must be used though as the needle will be passed through it before the skin. This is not always acceptable practice, as there are many different approaches to performing guided injections. Always check with your employer, or seek local guidance and have a policy in place for how you should perform a sterile injection technique – have it written as a step by step process!