Ultrasonic gel (i.e., medical ultrasound coupling agent) works by eliminating the air gap between the probe and the skin, forming a "bridge" for sound wave transmission. This allows ultrasound waves to efficiently penetrate human tissue, resulting in a clear image.
Specific principles are as follows:
Acoustic Impedance Matching: The acoustic impedance difference between air and human tissue is significant. Ultrasonic waves are reflected extensively at the air-skin interface, leading to energy loss. The acoustic impedance of ultrasonic gel is similar to that of human tissue, effectively reducing reflection and improving sound wave transmission efficiency, resulting in a clearer image.
Filling Tiny Gaps: The skin surface has wrinkles and depressions that easily trap air. The gel fully fills these gaps, ensuring a tight fit between the probe and the skin and preventing signal interruption.
Lubrication: The gel's lubricating properties allow the probe to glide more smoothly on the skin, reducing friction and discomfort, and improving examination comfort.
Furthermore, modern medical coupling agents are mostly water-based polymer gels with safe and non-toxic ingredients. They are easy to wipe off or rinse with water after examination and will not contaminate the skin or clothing.