What Is Shortwave Diathermy?

Short Wave Therapy (Short Wave Therapy) uses high-frequency alternating current with a wavelength of 100-10 meters to generate magnetic or electric field energy in the body, and mainly uses high-frequency electromagnetic field energy to treat diseases. Because it uses cable coil electrodes, during treatment, high-frequency alternating electromagnetic fields are mainly used to induce eddy currents when passing through the conductor tissue, which causes the tissue to generate heat, so it is also called induction diathermy therapy.

Short wave therapy

Short Wave Therapy (Short Wave Therapy) uses high-frequency alternating current with a wavelength of 100-10 meters to generate magnetic or electric field energy in the body, and mainly uses high-frequency electromagnetic field energy to treat diseases. Because it uses cable coil electrodes, during treatment, high-frequency alternating electromagnetic fields are mainly used to induce eddy currents when passing through the conductor tissue, which causes the tissue to generate heat, so it is also called induction diathermy therapy.

Chinese name

Short wave therapy

Foreign name

Short wave therapy

Application time

1937

Application wavelength

100-10 meters

Shortwave therapy was widely used clinically after 1937. Animal experiments and clinical applications of pulsed short-wave electrotherapy were reported in 1949, and it was believed that this electrotherapy had a significant impact on inflammation, pain, and wound healing, but it has not been promoted so far.

Shortwave electrotherapy can also be used in addition to general treatment

(1) Wavelength (): 100-10 meters

(2) Frequency (f): 3-30 million Hz

(Three) output current: several amps

(IV) Current curve: There are two types of continuous amplitude oscillation and pulse oscillation.

(5) In recent years, a short-wave therapeutic machine with high power has been developed, with an output power of more than 1,000 watts; a wavelength of 22.124 meters and a frequency of 13.560 MHz, which is suitable for tumor treatment in various parts. It is called radiofrequency therapy.

(A) the electrode can leave the skin during treatment

As the frequency of the short-wave current increases by more than 10 MHz, the capacitive capacitance (XC = 1 / 2fc) between the skin electrodes decreases to hundreds or tens of ohms, and the current is easy to pass, so the electrodes can leave the skin during short-wave treatment. This makes it easy to operate and can be treated through clothes. It is suitable for treating uneven areas, avoiding overheating of skin and subcutaneous fat, uniform heat production, and achieving a greater depth of treatment.

(B) the effect is more uniform

As described in the first section of this chapter, due to the high short-wave frequency, the capacitive reactance of the tissue capacitance to this current is significantly reduced, and the capacitance and resistance parts of the tissue are easily passed. Therefore, the distribution of current in the tissue is not only lower than that of the medium-frequency The electric time is uniform, and it is much more uniform than the medium wave.

(3) Deep heat generation and its characteristics

When the high-frequency AC cable pole ring acts on the human body, eddy currents are generated in the body due to high-frequency magnetic field induction. Eddy current basically belongs to a kind of conduction current, which mainly passes along a path with less resistance (lymph, blood-rich tissue). The principle of heat generation is similar to that when it passes through a conductor. The heat generation in a unit volume of tissue per unit time depends on the formula.

Q = kf2H2g = k2f2 H2 / r = kf22 (NI) 2 / R. Q-heat generation, g-electrical conductivity, H-magnetic field strength, f-frequency, -magnetic permeability coefficient, R-resistance.

It can be known from the formula that the higher f, the stronger the H formed around the cable, and the smaller the R of the organization, the greater the heat generation. Because muscle R is much smaller than fat, tissues with small R such as muscle will produce more heat than fat. However, in reality, because the muscle layer is thicker than fat, the most important thing is that the muscles are rich in blood vessels and blood circulation, so that most of the heat is taken away by the blood flow, so the temperature of the muscle is actually double or similar to that of fat. It is possible to completely avoid "fat overheating" of the subcutaneous tissue, and focus on muscles, liver, kidneys and other solid organs or other tissues with low resistance, which is one of the important advantages of short-wave cable field.

And because eddy currents are mainly generated in tissues with low resistance (rich blood and lymph), the cable energy is mostly consumed in these tissues, so the tissue deeper than the muscle layer gets less energy. This is because the coil field is not as large as the gap. The reason for the deep capacitance effect. The short-wave electric field method is similar to the ultra-short wave.

Several points related to treatment can be summarized from the above:

1. Short wave treatment is deeper than medium wave (about 6-8cm) and uniform. When micro heat is used in deep tissues, the temperature can be increased by 1-1.5 ° C, and the temperature can be increased by 2-3 ° C.

2. For the treatment of superficial tissues such as skin and subcutaneous fat, the capacitive electric field method must be used, and the distance between the electrode and the skin should be closer.

3. Capacitive electric field method is also needed to treat deep tissues, cavity organs, bones, etc., but the distance between the electrode and the skin should be larger. Otherwise, the skin and subcutaneous "fat overheating" hinder the in-depth effect.

4. The coil field method is a good method to bypass skin and subcutaneous fat, focusing on muscles and tissues with low resistivity, but the disadvantages of this method are that the effect on deep tissue organs is still small, and the resistivity to bones is large. The role of the organization is small. However, in recent years, there have been reports of improved electrode operation methods for treating deep organ diseases.

The mechanism of short-wave electrotherapy, in addition to deep heat production, also has a special high-frequency oscillation effect. The greater the energy absorbed by the tissue, the more heat is formed, and the greater the thermal effect, the smaller the oscillation effect.

Shortwave can congest deep tissues, promote blood and lymphatic circulation, enhance the regeneration process, reduce the excitability of the central and peripheral nervous system, enhance leukocyte phagocytosis, and activate enzyme activities; when it acts on the adrenal region, it can promote the adrenal cortex glucocortex Hormonal secretion function, improve the secretion of catecholamines; when it acts on vegetative nerves, it can reduce the sympathetic nerve and vagus nerve, so short-wave electrotherapy can promote blood circulation, relieve spasm (gastrointestinal smooth muscle spasm), relieve pain, anti-inflammatory, and promote the absorption of pathological products Enhance tissue organ metabolism and nutrition.

High-power short-wave (referred to as RF therapy) can be used for tumor treatment (see the appendix for details), which can make the temperature inside the tumor 5 ° C-10 ° C higher than the temperature of healthy tissue, thereby achieving the purpose of cancer cell death without damaging normal tissue. Therefore, in the past ten years, it has been used for research and treatment of malignant tumors. Especially when it is reasonably integrated with radiation, chemotherapy, surgery, etc., it can significantly improve the cure rate of malignant tumors. There are still many problems in RF therapy to be solved.

In addition, short-wave can also be used in conjunction with the direct current drug iontophoresis method, which can make the drug introduction deeper and deeper than the simple direct current method.

The application of short-wave and low-frequency electricity at the same time can improve cell membrane permeability, improve metabolism, and have a good effect on the functions of vegetative nerves, motor nerves and muscles.

Short-wave current can also be used for electro-cutting and electro-coagulation, and its structural changes and uses are similar to those of medium-wave.

Five, equipment and treatment methods

(1) The domestic short-wave therapeutic machine. The output voltage is 90-120 volts (low power machine) and 300-400 volts (high power machine). The former has a maximum power of 70 watts and the latter is 250-300 watts.

The oscillation circuit of the short-wave therapeutic machine mainly uses a push-pull type, and is composed of a three-stage vacuum tube and the like to generate high-frequency continuous equal-amplitude oscillating alternating current.

(II) Treatment methods There are many factors that affect the treatment during short-wave treatment. The electrode size, placement method, location, and air gap dose size must be selected according to the nature of the lesion, the location and scope of the effect.

There are generally three types of shortwave therapy

Coil electrode

(1) Variable type (such as cable electrode) and fixed type (such as disk electrode and eddy current electrode).

(2) Cable electrodes are used for the long and large parts of the spine and limbs, disk electrodes are used for large areas such as the chest, abdomen, and lower back; eddy current electrodes are used for the small features, head, face, and small lesions.

(3) Distribution of electromagnetic fields formed by cable coils

When high-frequency current passes through the coil conductor, electromagnetic field induction occurs. Some people have researched that when the short-wave current passes through the cable, the magnetic field and the electric field are different. The electric field is the strongest at the two ends of the cable and the middle is weak; and the magnetic field is weak at the two ends and the middle is the strongest. Therefore, the resistivity of the intended treatment is small For tissues and organs such as muscles, the middle of the cable should be taken. If it is intended to treat tissues with a large electrical resistivity, such as joint ligaments that can connective tissue, the two ends of the cable should be used because the electric field can easily pass through tissues with large electrical resistance.

(4) Too many turns of the cable will affect the output of the high-frequency electric field. Generally, 1-4 turns are used. The distance between the cable coils should not be too close. It is estimated that the distance between the coils should be greater than 1 cm. In order to make the magnetic field lines act in the deep part, a certain distance should be kept between the human body and the cable. Generally it is about 1-2.5cm (or 1 / 2r, r is the limb radius).

(5) The winding method of the cable coil is a high-voltage insulated wire, and the longest cable length is 1/2, 1/4, or 3/4. Depending on the treatment site, the cable can be wound into different shapes. During the treatment of the limbs, the cable must be rotated in the same direction. Do not rotate the two ends of the cable in opposite directions to prevent the magnetic lines of different directions from interfering with each other and weakening.

(Three) disc electrode and eddy current electrode

This is an electrode coiled in a round bakelite box. There are two types of electrodes.

1. The electric disk electrode winds the cable into a clock spring shape, puts it into a round bakelite box, and then fixes it on the movable support arm. It is called a disk electrode or a cable disk electrode (Figure 5.3.5).

2. Ideal eddy current electrode There are two types of eddy current electrode: large eddy current electrode (monode) and small eddy current electrode (minode). The diameter of the large electrode is 14cm, the size of the small electrode is 5.5cm, and the output power is 200 watts. Site treatment. The latter is 70 watts and is suitable for the treatment of head, neck, armpit and facet joints. Eddy current electrodes are mainly suitable for short waves at 27.12MHz frequency. This electrode consists of 3 to 4 turns of a metal conduit ring with a capacitor connected at both ends. The conduit is spiral and not on a plane. The distance between the turns is large to reduce the capacitance between the turns. The capacitance decreases and the electric field strength decreases accordingly. As the magnetic field strength increases, the eddy current generated in the human body also increases. Capacitors are connected at both ends of the catheter to form an oscillating circuit to reduce the effect of the electric field on the human body and the magnetic field. The whole electrode is installed in a bakelite box or a plastic box, and the electrode treatment can be selected according to the size of the active site. During the treatment, only induction heating and no capacitive heating were used. This type of electrode acts on the human body in the form of a single pole. The magnetic field in the electrode causes the human body to generate eddy currents. The electrode diameter is not large, and it is more convenient to act on the head and limbs. The maximum action depth is 8cm.

(Four) capacitor electrode

Capacitor electrodes are made of thin metal sheets or metal nets with rubber or felt. It is also possible to use glass plates with metal plate-shaped electrodes. The distance between the metal sheets can be adjusted to adjust the distance between the skin electrodes according to the depth of the lesion. The juxtaposition and the opposite method can be adopted according to the condition of the lesion. This method is mainly based on the electric field, which can form a large amount of thermal energy in fat, and can reach a considerable depth.

(E) The dose is generally determined based on the warm sensation of the patient during treatment.

1. Patients without heat have no sense of warmth, the neon tube has just started to glow, and the light is dim.

2. The slight heat just has a warm feeling, the neon tube is all bright, and the light is dim.

3. Warm heat and comfortable warmth, neon tube is bright.

4. The heat is obviously strong, but can withstand it, and the neon tube is bright.

Also refer to the machine instrument pointer parameter (mA). Because each machine standard is different, it can be determined in combination with specific machine conditions. Short-wave therapy is usually performed with warm heat and caloric therapy, usually once a day or once every other day, 15-20 minutes each time, up to 30 minutes as needed, and 12-18-24 times as a course of treatment.

1. Short wave cable right thigh, 3-4 turns, air distance 2cm, warm heat (or heat), 10'-15'-20 'once a day 12-20 times.

Indications: Right femoral deep phlebitis (chronic phase), rheumatic myositis.

2. Short wave (high power machine), large eddy current electrode, ureteral calculi on the back, air distance 1cm, warm and heat, once a day, 20-30 minutes each time, a total of 20 times.

Indications: ureteral stones

3. Short-wave cable disc interscapular region, air distance 1-1.5cm, slight heat or warm heat, once a day or every other day, 20-15 minutes 10-15 times.

Indications: chronic or subacute bronchitis, non-specific pneumonia

4. Short wave cable limb fracture plane, 3 circles (if plaster is fixed, plaster should be covered with a dry towel), micro-calorie once a day, 15-30 minutes each time, 15-20 times for a course of treatment.

Indications: Chronic osteomyelitis of the femur or tibia with fractures of the upper and lower limbs.