What is the liquid used for B-ultrasound

B-ultrasound is a medical term. There are many diseases that require B-ultrasound. For example, during pregnancy, if there are problems with the internal organs or abdominal cavity, B-ultrasound is needed for examination. We can only see an image moving back and forth on the screen, but professional doctors can tell what the problem is. When doing B-ultrasound, a layer of liquid will be applied on the belly, and it feels icy. What is this layer of liquid?

The medical term B-ultrasound is not a strange word to pregnant women who often go to the hospital for physical examinations, especially to check their internal organs, and to undergo regular obstetric examinations to protect the fetus.

When undergoing this examination, the person participating in the examination will often have a layer of liquid-like substance smeared on their stomach. It is cool, gelatinous, and sticky to the touch. What is this? Will it cause some harm to the human body? Many people are secretly worried.

Ordinary people are familiar with the name of B-ultrasound, but they may not be familiar with its principles. It’s actually not that complicated to say. It’s related to something we learned in junior high school physics, which is ultrasound. Ultrasound is scientifically defined as a sound wave with a frequency far higher than the normal hearing range of ordinary humans. Even middle school students know that if we look at it from a physical point of view, what people call sound is actually a wave. It cannot propagate in a vacuum and must rely on a medium to successfully propagate. The medium is divided into three types: solid, liquid, and gas. Because the acoustic impedance of solids is the smallest, it is not difficult for us to know that the propagation speed of sound waves is the fastest in solids, slower in liquids, and slowest in gases.

Scientists have discovered an interesting phenomenon: when sound waves reach the junction of two media, part of the sound waves will be reflected to the sound source. If the difference in acoustic impedance between the two media is large, more sound waves will be reflected back.

The scientific principles of sound waves are of course also applicable to ultrasound. However, ultrasound is more powerful than ordinary sound waves in that it has strong penetrating power and is even more penetrating than light in solids. This provides an idea for clinical examinations, and it is entirely possible to observe the specific conditions inside the human body by using ultrasound to penetrate the human body. This is why, if you want to see the internal organs and the fetus, you have to do a B-ultrasound.

Having said that, it seems that there is still no mention of the specific use of this transparent colloid. The application of this layer of colloid is related to a guest who is very easy to be ignored. You guessed it right, this difficult guest is the air. There is not a completely seamless connection between the ultrasound instrument probe and the human skin. There is invisible and intangible air in between. As mentioned above, the acoustic impedance of air is relatively large. If the layer of air between the probe and the skin cannot be eliminated, the image of the human body obtained by the doctor will be very blurry. This also fails to achieve the ideal medical effect.