​​What is the Gel that is applied before an Ultrasound Scan? | Curiosity Tea

​​What is the Gel that is applied before an Ultrasound Scan?

Have you ever had an ultrasound scan? Perhaps if you have a baby, you would have tried it. Do you remember? Before ultrasound scanning, one thing is prepared. It is the gel. The gel is applied to the scan area, before contacting the ultrasound probe to your body.

Ultrasonic waves generated from the probe are reflected from the boundary of the tissue, and the probe receive reflected waves to make an ultrasound image. However, the larger the difference in acoustic characteristics between the two tissues, the stronger the reflection and the stronger the echo (white on the screen) appears. The acoustic properties (resistance) of each tissue are related to their density, which is greater in order of bone> soft tissue> fat> air.

Therefore, if you apply ultrasonic probe without gel, 99.9% of ultrasonic waves are reflected at the boundary of air-soft tissue (body). Ultrasound image should show the difference between the tissues in the body (normal-lesion, etc.), not the difference between the air and body.

To solve this situation, the gel is used. In other words, when the acoustic resistance of the two media is made equal by using gel, ultrasonic waves are transmitted to body without reflection. The other purpose of the gel is the role of lubricantion, which moves the probe smoothly when performing a ultrasound scan. If the gel is not used, it may be stiff and the patient may feel pain.