Ultrasonic coupling agent

With the development of science and technology and the progress of society, many convenient medical devices have appeared in medicine. The B-ultrasound and X-ray treatments we usually talk about are all based on the principle of ultrasound. There is an auxiliary product that goes with these instruments, which is coupling agent. Coupling agent is a non-toxic, harmless and odorless liquid used in medical diagnosis. It allows you to see the data displayed on the instrument more clearly and provide more accurate diagnosis and treatment. Let's explore ultrasonic coupling agent together.

(1) Classification Industrial coupling agents are mainly based on engine oil, transformer oil, grease, glycerin, water glass (sodium silicate Na2SiO3) or industrial glue, chemical paste, or commercial ultrasonic testing special coupling agents as coupling agents Medical coupling agents (2) Features The pH value is neutral, non-toxic, odorless, non-irritating, does not stick to the skin and clothes, has no irritation to the skin, no allergic reaction, and is easy to wipe off. It has good thixotropy and does not flow, and is easy to operate. Good stability and not affected by climate change. (3) It can be used in A-type, B-type, and M-type ultrasonic diagnostic instruments and Doppler blood flow meters. It is suitable for obstetrics and gynecology, digestive system, urinary system, nervous system, newborn, thyroid and breast examinations. It can couple with ultrasonic probes to improve display clarity and has excellent effects. It does not need to be applied repeatedly, which helps save diagnostic time. (4) Application: Because the frequency of medical ultrasound is 2.5-5M, it cannot be transmitted in the air. If there is air between the probe and the skin, the ultrasound will return as soon as it encounters the air and cannot enter the human body, thus failing to play a role in the inspection. Applying a layer of coupling agent on the skin first can eliminate the air between the probe and the skin.

1. Concept of Ultrasonic Couplant

During ultrasound examination, the air between the probe and the patient's skin will hinder the transmission of ultrasound waves into the human body. In order to obtain high-quality images, a liquid conductive medium is required to connect the probe and the patient's body surface. This medium is the coupling agent.

2. Reasons for using ultrasonic coupling agent

The purpose of using ultrasonic coupling agent is first to fill the tiny gaps between the contact surfaces to prevent the trace air in these gaps from affecting the penetration of ultrasound; secondly, through the "transition" effect of the coupling agent, the acoustic impedance difference between the probe and the skin is reduced, thereby reducing the reflection loss of ultrasonic energy at this interface. In addition, it also plays a "lubricating" role, reducing the friction between the probe surface and the skin, allowing the probe to slide flexibly for exploration.

3. Impact of Ultrasonic Coupling Agent on Images

The quality of the coupling agent is closely related to the quality of the obtained sonogram. Poor quality coupling agent can cause ultrasonic energy loss, reduced resolution, blurred images, and even irritate the skin and damage the probe. (5) Application of industrial coupling agent Industrial coupling agent is used to remove the air between the probe and the object to be measured, so that the ultrasonic wave can effectively penetrate the workpiece to achieve the purpose of detection. If the type or method of use is inappropriate, it will cause errors or the coupling mark will flash and measurement will be impossible. The appropriate type should be selected according to the usage. When used on smooth material surfaces, low-viscosity coupling agents can be used; when used on rough surfaces, vertical surfaces and top surfaces, high-viscosity coupling agents should be used. High-temperature coupling agent should be used for high-temperature workpieces. Secondly, the coupling agent should be used in an appropriate amount and applied evenly. Generally, the coupling agent should be applied to the surface of the material being measured, but when the measurement temperature is high, the coupling agent should be applied to the probe.