What Is a Therapeutic Ultrasound?

Utilizing ultrasound energy at a frequency of 800 to 1000 kHz to treat the body in various ways.

Ultrasound therapy

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Utilizing ultrasound energy at a frequency of 800 to 1000 kHz to treat the body in various ways.

Chinese name

Ultrasound therapy

Frequency

800 1000 kHz

Technology

Ultrasound

Therapeutic effect

Analgesics, antispasmodics, etc.

A method of treating diseases by using ultrasonic waves on the human body. The ultrasonic frequency used is mostly between 800-1000kHz. Human tissues have different structures, different acoustic resistances, and form many interfaces between different tissues. The propagation path of ultrasonic waves in a uniform body tissue is straight, but when it encounters the interface, it is refracted or reflected. During the transmission process, ultrasound has obvious mechanical and thermal effects on tissues, causing a series of physical and chemical changes in the body, so it can adjust human body functions, improve or eliminate pathological processes, and promote the recovery of diseased tissues. Ultrasound can enter the human body in a variety of ways, and the size of the human body's response to the ultrasound depends on the energy of the ultrasound and the functional status of the human body.

Ultrasound therapy can also be combined with other physical factor treatment methods, such as simultaneous application with other (such as inter-electrodynamic electrotherapy, ultrasonic intermediate-frequency electrotherapy), or combined application (such as first ultrasound therapy, followed by sports therapy) to improve efficacy. Ultrasonic drug penetration therapy and ultrasonic nebulization inhalation therapy have good clinical application effects. Ultrasound heating for cancer treatment, ultrasonic lithotripsy, ultrasonic surgery (Using ultrasonic vibration energy and locally converted thermal energy to cut tissue, see

The main effects of ultrasound on the human body are:

Mechanical action is the basic effect of ultrasound on the human body. Ultrasound is called traveling wave when it propagates straight in the tissue without reflection. It causes the particles in the medium to alternately compress and stretch, resulting in huge acceleration or deceleration. When ultrasound travels in human tissues, it encounters the interface and generates reflection. If the distance between the ultrasonic generator wafer and the reflective interface is a multiple of 1/2 wavelength, the direct wave and the reflected wave meet to form a standing wave, and its maximum amplitude is the sum of the two wave amplitudes. , The minimum amplitude is the difference between the two wave amplitudes. It causes different mass points in the medium to be subject to different levels of pressure and tension, so that the forced masses can move at different speeds, and frictional forces will be generated between the masses with different speeds. The two kinds of mechanical actions mentioned above give a subtle massage to the cells, enhance the permeability of the cell membrane, promote the flow of cytoplasm inside the cells, improve the metabolic function of the tissue, and be conducive to the recovery of pathological changes.

Thermal effect. Ultrasound heats tissues as a result of the conversion of acoustic energy into thermal energy. Factors affecting this energy conversion include the intensity of ultrasound, the way it acts on the human body, the density and consistency of tissue, the size of tissue acoustic impedance, and the state of local tissue blood circulation. Experiments have shown that nerve tissue is most likely to generate heat under ultrasound, muscle is second, and fat tissue is the least. The acoustic impedance of bone and its surrounding tissues is very different, so it generates more heat at its interface.

Other physical and chemical effects. The mechanical and thermal effects of ultrasound can further promote or induce other physical and chemical changes in the tissue. Ultrasound has a diffusion effect, can change the permeability of the membrane system, change the composition ratio of substances in local tissues, and thereby change the ion concentration and the potential inside and outside the cell membrane. Ultrasound decomposes and polymerizes polymer compounds, decomposing larger molecules into smaller molecules, changing the role of molecules, and affecting the physicochemical process. Ultrasound can also destroy the chemical bonds of some substances to form more active free radicals and cause polymerization reactions. Ultrasound can transform the gel in the body into a sol state, so it can treat the degenerative changes of muscles, tendons and ligaments, improve its dehydration state, and enhance its elasticity. Generally, the pH value of tissue fluid increases under the action of ultrasound and is alkaline, so it can reduce the local acidosis caused by inflammation.

The main therapeutic effects of ultrasound are as follows:

Analgesic and antispasmodic. Nerve conduction is suppressed by ultrasound, and muscle excitability decreases, thereby receiving analgesic and antispasmodic effects.

Soften and eliminate scar tissue. Ultrasound can soften and eliminate scar tissue, so it is often used to loosen adhesions, treat hypertrophic scars, joint contractures, trauma or post-operative adhesions, inflammatory thickening of tendons and tendon sheaths, etc.

accelerate local blood flow. Increase membrane permeability, promote substance exchange, and improve metabolic processes. Therefore, it can promote the regeneration and repair of diseased tissues, subside the edema caused by inflammation, and accelerate the absorption of trauma or postoperative hematoma. Because ultrasound can improve local blood flow, ultrasound can be used in the anterior region of the heart to treat coronary heart disease and applied to the skull to treat cerebrovascular accident sequelae.

Increase the local tissue temperature. The blood flow in malignant tumors is lower than the surrounding normal tissues. Ultrasound is used to accumulate heat in the tumor and increase the temperature to kill the malignant tumor cells.

Simultaneous application of ultrasound and electrokinetic electricity can significantly improve the effect of single treatment; ultrasound can penetrate the drug into the intact mucosa and skin, and the effect is good; ultrasound can also atomize the medicine solution and inhale it through the respiratory tract to treat respiratory diseases.

The effect of ultrasound on the human body is closely related to the ultrasound dose used. The dose size depends on the ultrasonic intensity (in W / cm2) output by the instrument, the duration of the action, and the method of use (fixed method is greater than mobile method). The clinical application dose is shown in the table.

Ultrasound intensity greater than 2.0W / cm2 has a tingling sensation to the skin, and it is rarely used in clinical except for the treatment of malignant tumors. The average power of pulsed ultrasound is less than that of continuous ultrasound, so pulsed ultrasound treatment is easier to tolerate than continuous ultrasound treatment, and the former dose can be slightly greater than the latter.

Soft tissue injury, hematoma, joint contracture, periarthritis, bursitis, tendon and tenosynovitis, phantom limb pain due to milk sweat accumulation, scars and adhesions, cerebrovascular disease, peripheral nerve injury and inflammation, thromboocclusive vasculitis, etc. Ultra-dose ultrasound can be used for local heating to treat malignant tumors.

Severe heart failure, cachexia, high fever, hemorrhagic disease, acute purulent inflammation, severe local circulatory disorders, etc. Bibliography Guo Wanxue, chief editor: Physical Therapy, People's Medical Publishing House, Beijing, 1984. Chief Editor of Chinese Rehabilitation Research Association: "Rehabilitation Medicine", People's Medical Publishing House, Beijing, 1984.