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Electrosurgery
Electrosurgery is the application of a high-frequency (radio frequency) alternating polarity, electrical current to biological tissue as a means to cut, coagulate, desiccate, or fulgurate tissue.Hainer BL, "Fundamentals of electrosurgery", ''Journal of the American Board of Family Practice'', 4(6):419–26, 1991 Nov.–Dec. 400 V peak-to-peak) the vapor sheath is ionized, forming conductive plasma. Electric current continues to flow from the metal electrode through the ionized gas into the tissue. Rapid overheating of tissue results in its vaporization, fragmentation and ejection of fragments, allowing for tissue cutting. In applications of a continuous wave the heat diffusion typically leads to formation of a significant thermal damage zone at the edges of the lesion. Open circuit voltage in electrosurgical waveforms is typically in the range of 300–10,000 V peak-to-peak. Higher precision can be achieved with pulsed waveforms. Using bursts of several tens of microseconds in d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diathermy
Diathermy is electrically induced heat or the use of high-frequency electromagnetic currents as a form of physical therapy and in surgical procedures. The earliest observations on the reactions of high-frequency electromagnetic currents upon the human organism were made by Jacques Arsene d'Arsonval. The field was pioneered in 1907 by German physician Karl Franz Nagelschmidt, who coined the term ''diathermy'' from the Greek words ''dia'' and θέρμη ''therma'', literally meaning "heating through" (adj., diather´mal, diather´mic). Diathermy is commonly used for muscle relaxation, and to induce deep heating in tissue for therapeutic purposes in medicine. It is used in physical therapy to deliver moderate heat directly to pathologic lesions in the deeper tissues of the body. Diathermy is produced by three techniques: ultrasound (''ultrasonic diathermy''), short-wave radio frequencies in the range 1–100 MHz (''shortwave diathermy'') or microwaves typically in the 915&nb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diathermy
Diathermy is electrically induced heat or the use of high-frequency electromagnetic currents as a form of physical therapy and in surgical procedures. The earliest observations on the reactions of high-frequency electromagnetic currents upon the human organism were made by Jacques Arsene d'Arsonval. The field was pioneered in 1907 by German physician Karl Franz Nagelschmidt, who coined the term ''diathermy'' from the Greek words ''dia'' and θέρμη ''therma'', literally meaning "heating through" (adj., diather´mal, diather´mic). Diathermy is commonly used for muscle relaxation, and to induce deep heating in tissue for therapeutic purposes in medicine. It is used in physical therapy to deliver moderate heat directly to pathologic lesions in the deeper tissues of the body. Diathermy is produced by three techniques: ultrasound (''ultrasonic diathermy''), short-wave radio frequencies in the range 1–100 MHz (''shortwave diathermy'') or microwaves typically in the 915&nb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fulguration
Radiofrequency ablation (RFA), also called fulguration, is a medical procedure in which part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from medium frequency alternating current (in the range of 350–500 kHz). RFA is generally conducted in the outpatient setting, using either local anesthetics or conscious sedation anesthesia. When it is delivered via catheter, it is called radiofrequency catheter ablation. Two important advantages of radio frequency current (over previously used low frequency AC or pulses of DC) are that it does not directly stimulate nerves or heart muscle and therefore can often be used without the need for general anesthesia, and that it is very specific for treating the desired tissue without significant collateral damage; due to this, it is gaining in popularity as an alternative for eligible patients who do not want to undergo surgery. Documented benefits have led to RFA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cauterization
Cauterization (or cauterisation, or cautery) is a medical practice or technique of burning a part of a body to remove or close off a part of it. It destroys some tissue in an attempt to mitigate bleeding and damage, remove an undesired growth, or minimize other potential medical harm, such as infections when antibiotics are unavailable. The practice was once widespread for treatment of wounds. Its utility before the advent of antibiotics was said to be effective at more than one level: *To prevent exsanguination *To close amputations Cautery was historically believed to prevent infection, but current research shows that cautery actually increases the risk for infection by causing more tissue damage and providing a more hospitable environment for bacterial growth. Actual cautery refers to the metal device, generally heated to a dull red glow, that a physician applies to produce blisters, to stop bleeding of a blood vessel, and for other similar purposes., page 16. The main forms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrocautery
Cauterization (or cauterisation, or cautery) is a medical practice or technique of burning a part of a body to remove or close off a part of it. It destroys some tissue in an attempt to mitigate bleeding and damage, remove an undesired growth, or minimize other potential medical harm, such as infections when antibiotics are unavailable. The practice was once widespread for treatment of wounds. Its utility before the advent of antibiotics was said to be effective at more than one level: *To prevent exsanguination *To close amputations Cautery was historically believed to prevent infection, but current research shows that cautery actually increases the risk for infection by causing more tissue damage and providing a more hospitable environment for bacterial growth. Actual cautery refers to the metal device, generally heated to a dull red glow, that a physician applies to produce blisters, to stop bleeding of a blood vessel, and for other similar purposes., page 16. The main forms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dielectric Heating
Dielectric heating, also known as electronic heating, radio frequency heating, and high-frequency heating, is the process in which a radio frequency (RF) alternating electric field, or radio wave or microwave electromagnetic radiation heats a dielectric material. At higher frequencies, this heating is caused by molecular dipole rotation within the dielectric. Mechanism Molecular rotation occurs in materials containing polar molecules having an electrical dipole moment, with the consequence that they will align themselves in an electromagnetic field. If the field is oscillating, as it is in an electromagnetic wave or in a rapidly oscillating electric field, these molecules rotate continuously by aligning with it. This is called dipole rotation, or dipolar polarisation. As the field alternates, the molecules reverse direction. Rotating molecules push, pull, and collide with other molecules (through electrical forces), distributing the energy to adjacent molecules and atoms in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Arc
An electric arc, or arc discharge, is an electrical breakdown of a gas that produces a prolonged electrical discharge. The electric current, current through a normally Electrical conductance, nonconductive medium such as air produces a plasma (physics), plasma; the plasma may produce visible light. An arc discharge is characterized by a lower voltage than a glow discharge and relies on thermionic emission of electrons from the electrodes supporting the arc. An archaic term is voltaic arc, as used in the phrase "voltaic arc lamp". Techniques for arc suppression can be used to reduce the duration or likelihood of arc formation. In the late 19th century, Arc lamp, electric arc lighting was in wide use for Street light#Arc lamps, public lighting. Some low-pressure electric arcs are used in many applications. For example, fluorescent lamp, fluorescent tubes, mercury, sodium, and metal-halide lamps are used for lighting; xenon arc lamps have been used for movie projectors. Electric a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capacitance
Capacitance is the capability of a material object or device to store electric charge. It is measured by the change in charge in response to a difference in electric potential, expressed as the ratio of those quantities. Commonly recognized are two closely related notions of capacitance: ''self capacitance'' and ''mutual capacitance''. An object that can be electrically charged exhibits self capacitance, for which the electric potential is measured between the object and ground. Mutual capacitance is measured between two components, and is particularly important in the operations of the capacitor, a device designed for this purpose as an elementary Linear circuit, linear electronic component. Capacitance is a function only of the geometry of the design of the capacitor, e.g., the opposing surface area of the plates and the distance between them, and the permittivity of the dielectric material between the plates. For many dielectric materials, the permittivity and thus the capaci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Displacement Current
In electromagnetism, displacement current density is the quantity appearing in Maxwell's equations that is defined in terms of the rate of change of , the electric displacement field. Displacement current density has the same units as electric current density, and it is a source of the magnetic field just as actual current is. However it is not an electric current of moving charges, but a time-varying electric field. In physical materials (as opposed to vacuum), there is also a contribution from the slight motion of charges bound in atoms, called dielectric polarization. The idea was conceived by James Clerk Maxwell in his 1861 paper On Physical Lines of Force, Part III' in connection with the displacement of electric particles in a dielectric medium. Maxwell added displacement current to the electric current term in Ampère's Circuital Law. In his 1865 paper A Dynamical Theory of the Electromagnetic Field Maxwell used this amended version of Ampère's Circuital Law to de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyfrecator
A hyfrecator is a low-powered medical apparatus used in electrosurgery on conscious patients, usually in an office setting. It is used to destroy tissue directly, and to stop bleeding during minor surgery. It works by emitting low-power high-frequency high-voltage AC electrical pulses, via an electrode mounted on a handpiece, directly to the affected area of the body. A continuous electrical spark discharge may be drawn between probe and tissue, especially at the highest settings of power, although this is not necessary for the device to function. The amount of output power is adjustable, and the device is equipped with different tips, electrodes and forceps, depending on the electrosurgical requirement. Unlike other types of electrosurgery, the hyfrecator does not employ a dispersive electrode pad that is attached to the patient in an area not being treated, and that leads back to the apparatus (sometimes loosely but not quite correctly called a "ground pad"). It is designed to w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desiccation
Desiccation () is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. Industry Desiccation is widely employed in the oil and gas industry. These materials are obtained in a hydrated state, but the water content leads to corrosion or is incompatible with downstream processing. Removal of water is achieved by cryogenic condensation, absorption into glycols, and absorption onto desiccants such as silica gel. Laboratory A desiccator is a heavy glass or plastic container, now somewhat antiquated, used in practical chemistry for drying or keeping small amounts of materials very dry. The material is placed on a shelf, and a drying agent or ''desiccant'', such as dry silica gel or anhydrous sodium hydroxide, is placed below the shelf. Often some sort of humidity indicator is included in the desiccator to show, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipoma
A lipoma is a benign tumor made of fat tissue. They are generally soft to the touch, movable, and painless. They usually occur just under the skin, but occasionally may be deeper. Most are less than in size. Common locations include upper back, shoulders, and abdomen. It is possible to have a number of lipomas. The cause is generally unclear. Risk factors include family history, obesity, and lack of exercise. Diagnosis is typically based on a physical exam. Occasionally medical imaging or tissue biopsy is used to confirm the diagnosis. Treatment is typically by observation or surgical removal. Rarely, the condition may recur following removal, but this can generally be managed with repeat surgery. They are not generally associated with a future risk of cancer. Lipomas have a prevalence of roughly 2 out of every 100 people. Lipomas typically occur in adults between 40 and 60 years of age. Males are more often affected than females. They are the most common noncancerous soft-t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
