History of ultrasound

- Mar 19, 2019-

First, the international aspect:

From the end of the 19th century to the beginning of the 20th century, after the piezoelectric effect and the anti-piezoelectric effect were discovered in physics, people solved the method of generating ultrasonic waves by using electronic technology. From then on, the history chapter of developing and popularizing ultrasound technology was quickly unveiled.

In 1922, Germany patented the first invention of ultrasound therapy.

In 1939, a literature report on the clinical effects of ultrasound therapy was published.

In the late 1940s, ultrasound therapy was launched in Europe and the United States. It was not until the first International Conference on Medical Ultrasound in 1949 that the exchange of papers on ultrasound therapy was established, which laid the foundation for the development of ultrasound therapy. At the 2nd International Conference on Ultrasound Medicine in 1956, many papers were published, and ultrasound therapy entered a practical stage of maturity.

Second, the domestic aspect:

In the field of ultrasound therapy, it started later in the country. In the early 1950s, only a few hospitals underwent ultrasound treatment. From 1950, the first ultrasound therapy machine in 800KHz frequency was used in Beijing to treat various diseases, and it was gradually promoted in the 1950s. And have domestic instruments. Public literature reports were first seen in 1957. In the 1970s, various types of domestic ultrasonic therapeutic devices were used, and ultrasound therapy was popularized in major hospitals across the country.

For more than 40 years, major hospitals across the country have accumulated a considerable amount of information and rich clinical experience. In particular, ultrasound in vitro mechanical wave lithotripsy and ultrasound surgery, which appeared in the early 1980s, is a major breakthrough in the history of treatment of calculus. It has been promoted and applied internationally. High-intensity focused ultrasound non-invasive surgery has made ultrasound therapy an important place in contemporary medical technology. In the 21st century (HIFU) ultrasound focusing surgery has been hailed as the latest technology for the treatment of cancer in the 21st century.

Ultrasonic treatment mechanism:

1. Mechanical effect: The effect of ultrasound as it advances through the medium. (The propagation of ultrasound in a medium is a mechanical effect caused by reflection.) It can cause several reactions in the body. Ultrasonic vibration can cause the movement of substances in tissue cells. Due to the fine massage of ultrasound, the cytoplasm flow, cell oscillation, rotation, friction, and thus the effect of cell massage, also known as "internal massage" is unique to ultrasonic therapy. Characteristics can change the permeability of cell membrane, stimulate the dispersion process of semi-permeable membrane, promote metabolism, accelerate blood and lymph circulation, improve cell ischemia and hypoxia, improve tissue nutrition, change protein synthesis rate, and improve regeneration function. Changes in the internal structure of the cell, resulting in changes in the function of the cell, allowing the hard connective tissue to stretch and soften.

The mechanical action of ultrasound softens tissue, enhances penetration, enhances metabolism, promotes blood circulation, stimulates nervous system and cellular functions, and therefore has unique therapeutic significance for ultrasound.

2. Warming effect: Human tissue has a relatively large absorption power for ultrasonic energy. Therefore, when ultrasonic waves are propagated in human tissues, their energy is continuously absorbed by tissues and turned into heat, and as a result, the temperature of the tissue itself rises.

The heat production process is an energy conversion process in which mechanical energy is converted into heat energy in a medium. That is, endogenous heat. Ultrasound warming can increase blood circulation, accelerate metabolism, improve local tissue nutrition, and enhance enzyme activity. In general, the thermal effects of ultrasound are marked by bone and connective tissue, with minimal fat and blood.

3. Physical and chemical effects: Both the mechanical and thermal effects of ultrasound can trigger several physicochemical changes. Practice has proved that some physical and chemical effects are often secondary effects of the above effects. The TS-C treatment machine has the following five major effects through physical and chemical effects:

A. Dispersion: Ultrasound can improve the permeability of biofilm. After ultrasonic treatment, the cell membrane has a strong change in the permeability of potassium and calcium ions. Thereby enhancing the diffusion process of biofilm, promoting substance exchange, accelerating metabolism, and improving tissue nutrition.

B. Thixotropy: Under the action of ultrasound, the gel can be converted into a sol state. Softening effects on muscles, tendons, and pathological changes associated with tissue water deficits. Such as rheumatoid arthritis lesions and treatment of degenerative lesions of joints, tendons, and ligaments.

C. Cavitation: cavitation is formed, or a stable one-way vibration is maintained, or secondary expansion causes collapse, cell function changes, and intracellular calcium levels increase. Fibroblasts are activated, protein synthesis is increased, vascular permeability is increased, angiogenesis is accelerated, and collagen tension is increased.

D. Polymerization and depolymerization: Water molecule polymerization is the process of synthesizing multiple identical or similar molecules into one larger molecule. Macromolecular depolymerization is the process of turning macromolecular chemicals into small molecules. It can increase the activity of hydrolase and proenzyme in the joint.

E. Anti-inflammatory, repair cells and molecules: Under the action of ultrasound, the PH value of tissue can be developed to alkaline. Relieve local acidosis associated with inflammation. Ultrasound can affect blood flow, produce inflammatory effects, inhibit and play an anti-inflammatory role. Moves white blood cells and promotes angiogenesis. Collagen synthesis and maturation. Promotes or inhibits the repair and healing process of the injury. Thereby, the process of cleaning, activating and repairing the damaged cell tissue is achieved.

Quantum acoustics.

Ultrasonic can also be used for radar detection. Cleaning finer objects, such as clocks, can use ultrasonic waves to crush gallstones in patients, and can also use ultrasonic ranging.

Ultrasonic testing is also used to test the strength of solder joints for resistance welding.

The fluctuations that can be heard by the human ear are about 16 Hz to 20 kHz. If the frequency of the undulation is higher than this range, humans cannot hear it. It is called ultrasonic. The so-called "fluctuation" is in matter. The mechanical vibration of the particles when they are subjected to external force. For example, the object suspended under the spring is pulled down to extend the spring, and then the object is released, the object is subjected to the spring force to generate a reciprocating vibration. The deviation from the rest position is related to time, which is a sine wave.

Ultrasonic waves can be divided into longitudinal waves, transverse waves, surface waves, and blue waves according to the wave propagation direction. The transmission in the material is transmitted according to the law of energy immortality, and the sound wave is transmitted in a substance, or by a When a substance is introduced into another substance, its energy is inevitably weakened by the effects of attenuation, reflection and refraction; however, in the part where the material density is large, the sound pressure is increased (but the impedance is also changed). Large, the energy is still reduced, and vice versa, the volume is increased in the loose part.