| 单词 | diathermy | |||
| 释义 | diathermyenUKdi·a·ther·myD0200900 (dī′ə-thûr′mē)diathermy(ˈdaɪəˌθɜːmɪ) ordiathermiadi•a•ther•my(ˈdaɪ əˌθɜr mi)also di•a•ther•mi•a(ˌdaɪ əˈθɜr mi ə)n. diathermydiathermy
diathermyenUKdiathermy(dī`əthûr'mē), therapeutic measure used in medicine to generate heat in the body tissues. Electrodes and other instruments are used to transmit electric current to surface structures, thereby increasing the local blood circulation and facilitating and accelerating the process of absorption and repair. Diathermy is used for arthritis, bursitis, and other disorders of the tendons and muscles, as well as for certain other conditions requiring tissue repair. Because of the high-frequency current used in shortwave diathermy, care must be taken to avoid burning the patient's skin or injuring the deeper tissues.Diathermy(also endothermy, thermopenetration), one of the methods of electrotherapy that involves heating organs and tissues of the organism with high-frequency currents. The method was introduced into medical practice in 1905 by the Czech doctor R. von Zeynek. The term “diathermy” was proposed by the German doctor K. F. Nagelschmidt, who was working on the method at the same time. A strong current (up to 3 A) of high frequency (1.65 MHz) is used for diathermy. The amount of heat created in the organism is proportional to the square of the strength of the current passing through the conductor (tissues of the organism), the electrical resistance of the tissues, and the duration of the current. Therefore, a current of great strength is required if intensive heating of the tissues is needed. However, a strong direct or low-frequency current irritates sensitive nerves (sensations of pain). By increasing the frequency the irritating action of a strong current is reduced and practically disappears at a current of 3 A and a frequency of 1 MHz. The body’s tissues and organs do not have the same electrical conductivity. Because the skin, fat, bones, and muscles have the greatest resistance, they heat up the most, while organs rich in blood or lymph, such as the lungs, liver, and lymph nodes, have the least resistance and heat up less. High-frequency currents cause nonthermal (that is, specific) processes in the organism, the nature of which has not been clarified. It is hypothesized that the current causes the cell ions to shift to the borders of the cells. When a certain maximum concentration of ions is along the borders, the cell’s colloids precipitate out, and the cell passes to an excited state. The specific processes are more evident at a comparatively lower current frequency; at greater frequency, the thermal effect is more strongly marked. The action of diathermy is manifested in physiological reactions. The activity of the autonomous nervous system increases, which is expressed in intensified lymph and blood circulation and increased metabolism (in this case the body temperature may rise by 0.1°-0.2°C). Leucocyte activity also increases, especially in the area subjected to diathermy. The skeletal muscles and muscles of the internal organs relax, and the threshold of excitation of the sensory nerves increases. Therefore diathermy is used in the treatment of diseases based on spasms of the blood vessels, the urinary tract, the bile ducts, the gall bladder and other cavity organs as well as for chronic nonpurulent inflammatory diseases, inflammations of the nerves and their roots, neuralgias, and muscle, joint, and other pains. REFERENCESObrosov, A. N. Fizioterapevticheskaia tekhnika. Moscow, 1945.Kowarschik, J. Diatermiia. Moscow-Leningrad, 1931. (Translated from German.) Liventsev, N. M. Elektromeditsinskaia apparatura, 3rd ed. Moscow, 1964. Rukovodstvo po fizioterapii i fizioprofilaktike detskikh zabolevanii. Edited by A. N. Obrosov and K. V. Lapina. Moscow, 1968. V. G. IASNOGORODSKII diathermy[′dī·ə‚thər·mē]See diathermy diathermyenUKdiathermy[di´ah-ther″me]Diathermy is used in physical therapy to deliver moderate heat directly to pathologic lesions in the deeper tissues of the body. Surgically, the extreme heat that can be produced by diathermy may be used to destroy neoplasms, warts, and infected tissues, and to cauterize blood vessels to prevent excessive bleeding. The technique is particularly valuable in neurosurgery and surgery of the eye. The three forms of diathermy employed by physical therapists are short wave, ultrasound, and microwave. The application of moderate heat by diathermy increases blood flow and speeds up metabolism and the rate of ion diffusion across cellular membranes. The fibrous tissues in tendons, joint capsules, and scars are more easily stretched when subjected to heat, thus facilitating the relief of stiffness of joints and promoting relaxation of the muscles and decrease of muscle spasms. Short wave diathermy machines utilize two condenser plates that are placed on either side of the body part to be treated. Another mode of application is by induction coils that are pliable and can be molded to fit the part of the body under treatment. As the high-frequency waves travel through the body tissues between the condensers or the coils, they are converted into heat. The degree of heat and depth of penetration depend in part on the absorptive and resistance properties of the tissues that the waves encounter. The frequency allowed for short wave diathermy operations is under the control of the Federal Communications Commission. The frequencies assigned for short wave diathermy operations are 13.66, 27.33, and 40.98 megahertz. Most commercial machines operate at a frequency of 27.33 megahertz and a wavelength of 11 meters. Short wave diathermy usually is prescribed for treatment of deep muscles and joints that are covered with a heavy soft-tissue mass, for example, the hip. In some instances short wave diathermy may be applied to localize deep inflammatory processes, as in pelvic inflammatory disease. Ultrasound diathermy employs high-frequency acoustic vibrations which, when propelled through the tissues, are converted into heat. This type of diathermy is especially useful in the delivery of heat to selected musculatures and structures because there is a difference in the sensitivity of various fibers to the acoustic vibrations; some are more absorptive and some are more reflective. For example, in subcutaneous fat, relatively little energy is converted into heat, but in muscle tissues there is a much higher rate of conversion to heat. The therapeutic ultrasound apparatus generates a high-frequency alternating current, which is then converted into acoustic vibrations. The apparatus is moved slowly across the surface of the part being treated. Ultrasound is a very effective agent for the application of heat, but it should be used only by a therapist who is fully aware of its potential hazards and the contraindications for its use. Microwave diathermy uses radar waves, which are of higher frequency and shorter wavelength than radio waves. Most, if not all, of the therapeutic effects of microwave therapy are related to the conversion of energy into heat and its distribution throughout the body tissues. This mode of diathermy is considered to be the easiest to use, but the microwaves have a relatively poor depth of penetration. Microwaves cannot be used in high dosage on edematous tissue, over wet dressings, or near metallic implants in the body because of the danger of local burns. Microwaves and short waves cannot be used on or near persons with implanted electronic cardiac pacemakers. As with all forms of heat applications, care must be taken to avoid burns during diathermy treatments, especially to patients with decreased sensitivity to heat and cold. di·a·ther·my(dī'ă-ther-mē),diathermy(dī′ə-thûr′mē)diathermySports medicine The use of high-frequency electromagnetic waves to ↑ temperature of deep tissues due to resistance to the passage of energy Types Microwave diathermy, shortwave diathermy. See Microwave diathermy, Shortwave diathermy Surgery Cauterization, see there.di·a·ther·my(dī'ă-thĕr-mē)diathermyThe use of high-frequency alternating current to heat or burn tissues. Diathermy can be used to produce a diffuse warming effect or an intense local cutting or coagulating effect for bloodless surgery.Diathermydi·a·ther·my(dī'ă-thĕr-mē)diathermyenUK
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