The application of laser technology in the medical field Laser: Laser is the light emitted by atoms "excited" in the working substance. All light in its beam has high monochromaticity, high directivity, high brightness and good coherence. In medicine, it mainly uses the characteristics of laser high brightness and high directivity.
The laser controls the size of the focused spot through the lens and changes the power density, so that the temperature of the human body at a certain point can reach up to 200 ℃ -1000 ℃, in a very short time (0.1-10ms) to solidify and decompose the diseased tissue, and even melt and gasify . For example, the output end of the CO2 laser can obtain a focused spot less than 0.1 mm, which can move at a certain speed instead of the traditional surgical scalpel to vaporize various soft and hard tissues of the human body. It has high precision, small wounds, and fusion at any time. Basically Painless, sterile and less bleeding.
You can choose lasers of different wavelengths according to your needs, adjust the size of the light spot, cover the lesion area of ​​the human body for irradiation, penetrate into different depths for treatment, or cooperate with the computer and X-ray equipment to introduce the laser into the diseased organ in the body through the optical fiber. treatment. At present, laser has developed clinical medicine in the fields of heart, cancer, eyes, ears, nose, pharynx, teeth, skin, gynecology, orthopedics, and beauty, and has formed a brand-new medical branch-laser medicine.
The design and manufacture of various types of laser medical system equipment are also improving day by day, and the laser medical treatment of various medical specialties is being developed in depth.
1. The mechanism of laser treatment The results of various effects of laser treatment on organisms due to the high intensity of laser light produce strong thermal effects, photochemical reactions, optical pressure and electromagnetic field effects. Various clinical treatments can be performed according to these effects. Laser thermal effect: High-power laser can weld high melting point materials and cut metal plates, so of course cutting human muscles and skin is a matter of course. The 100-watt continuous laser is focused with an optical lens, which can reach a high temperature of 1000 degrees in 0.1 seconds, causing the muscle tissue to vaporize in an instant. When the focused light spot is reduced to the order of microns, the laser beam is equivalent to a light knife, which can perform various cutting operations. When laser is used in physiotherapy, its low-temperature thermal effect can play the role of anti-inflammatory, analgesic and regulate human body functions. Photochemical reaction: Biological organisms absorb laser light, causing some large molecules in cells to break down and lose their regeneration function. Human tissue contains a large amount of various pigments, which selectively absorb laser light and produce photochemical reactions.
For example, there are a lot of melanin particles between the cytoplasm and cells, which absorb laser light of a certain wavelength and produce a photochemical reaction, thereby destroying the entire cell. If these cells are diseased tissue, the laser irradiation becomes effective in inhibiting or eradicating the diseased tissue. In medical treatment, we always hope that the diseased tissue can absorb a large amount of laser light and destroy it, without affecting the normal tissue. The role of light pressure: It is common sense that light has pressure, but the pressure of ordinary light sources is very small and is not perceived by people. However, the light pressure generated by a strong laser, especially a strong pulse laser, is obvious. When the laser is blocked by a metal plate or cardboard, the sound of the laser light pressure can be heard, and sometimes a slight piece of paper can vibrate. Experiments show that if the laser energy density reaches 71080 W / cm2, the light pressure generated is about 3.4 dynes / cm2, which is equivalent to 3.4 to 10 atmospheres.
This pressure is not negligible on the human tissue, it will cause the local tissue of the human body to expand and deform. Electromagnetic field effect: Magnetic therapy relies on a magnetic field. The atoms and molecules of human cells are structured according to a certain structure and law. If due to a certain lesion or injury, a large amount of internal structure of the cell will be distorted, which will cause cell function to be impaired and the human body will feel uncomfortable. Electromagnetic fields can polarize molecules and atoms, thereby correcting distortion. The alternating field can also cause atoms and molecules to generate excitation vibrations, thereby restoring the vitality of cells.
2. Various applications of laser technology in the medical field: light blood test and anesthesia: blood test is one of the commonly used diagnostic methods before treating patients. The traditional method is blood test, which is time-consuming and inaccurate. Scientists at the Sandia National Laboratory in the United States recently invented a laser to measure blood cell morphology, which can measure multiple data of bleeding cells within a few minutes. The instrument is only the size of a postage stamp and can produce thousands of extremely thin lasers. A thin tube of a blood sample with an inner diameter of only 1/10 of the hair diameter is placed under the laser emitter. The laser light reflected and refracted by the blood cells is collected, then amplified and converted into electrical signals and input into a portable computer, and the computer displays images of synthetic blood cells based on these signals and measures accurate data of a large number of blood cells.
In the past, patients in hospitals have long been afraid of injections and injections of narcotic drugs, as well as frequent accidents of abandoned needles. In recent years, American researchers have developed a painless micro laser anesthesia device that burns a small hole with a diameter of 2 mm and a depth of 20 μm in the upper epidermis of the patient ’s skin with a red laser pulse. , Use liquid anesthetics such as lidocaine to enter the body directly, the skin is completely anesthetized within 3 minutes, and anesthetize tissues 25 cm deep within 6 minutes.
Laser eye disease treatment: Laser was first used in ophthalmology in 1961. For example, senile cataract is caused by a cloudy film on the surface of the transparent lens of the eyeball. The traditional medical method is to replace the lens and use the cornea or artificial corneal transplantation to make the patient see the light again. Now with low-power infrared laser irradiation, it can quickly vaporize and peel off a cloud-like film, restore transparent crystals, and restore vision. The glaucoma symptom is that the fluid channel in the eye is blocked, and the internal hydraulic pressure is too large, which damages the optic nerve and causes blurred vision and blindness. Now with the laser gasification method of appropriate wavelength and energy, a fine channel can be opened to allow the fluid in the eye to flow and restore vision. Retinal detachment can also be injected into the eye with a very thin laser beam from the pupil, melting the cells and proteins in the lesion into a colloid, thereby re-welding the retina to the fundus and restoring normal vision.
The above three laser treatments have been clinically applied in advanced foreign countries in the 1980s.
In recent years, Europe and other countries have made new progress in using lasers to correct myopia, hyperopia and astigmatism. For example, in myopia, the cornea is protruding or the eyeball is too long. As a result, the light is focused and imaged before the retina. The laser is used to "scrape" the convex part of the center of the cornea to restore the light image to the retina. For hyperopic eyes, the center of the cornea is too flat, so that the light is focused on the retina, and the peripheral tissue of the cornea is removed with a laser. The central part is relatively convex and imaged on the retina. For astigmatism, due to some small uneven structures on the cornea surface, the incident light is irregularly deflected in all directions, so that a clear image with strong contrast cannot be formed on the retina. The laser can be used to "flatten" the cornea to restore vision. Laser welding and healing: Rapidly stopping trauma or hemorrhage from liver surgery is a problem of traditional medicine. The thermal effect of instantaneous laser irradiation is now used to control the wounds or blood vessels that irradiate the human body just to reach a molten state without being vaporized. It can replace the traditional surgical suture operation and "welding", and it is not easy to be inflamed and recovers quickly after the operation.
In recent years, American medical expert Gregory has created laser healing technology success based on laser welding. Using a portable infrared laser and a kind of "elastin" hemostatic material, the laser irradiation elastin is directly integrated into the skin tissue of the wound or surgical incision during surgery, so as to achieve rapid healing of the affected area, and the surgical process is simple and easy. Laser treatment of dental diseases: People often do not pay attention to oral hygiene, long-term retention of food residues in the teeth between the fermentation caused by acid, microorganisms and bacteria, erosion of the tooth surface enamel is destroyed, there are small holes or hollow caries leading to nerves on the gum , Causing allergies to cold, hot, sour, sweet foods, toothache, swollen gums and bleeding. The traditional method is difficult to eliminate with fillings and extractions. Now with laser curettage, laser radiation is used to vaporize the diseased gums and kill the diseased cells. The caries holes are laser-cut and shaped and filled with ceramic materials.
Another better method is to use a laser to heat the enamel to about 1000 ° C to melt the enamel and re-solidify the enamel, as if it is new. Recently, the National University of Singapore has developed a low-energy short-pulse laser at a temperature of 400 ° C to melt the organic matrix on the surface of the tooth to fill the gaps between the enamel structures, forming a better protective layer, and the caries prevention effect reaches 98%. In addition, laser implants are used to make a hole in the tooth base with a laser, screw in a stainless steel screw, and fix a titanium alloy metal rod instead of the tooth base, and then use the laser to weld the metal denture to the metal rod. In this way, the installation of dentures is fast, reliable, and significantly improves the technology and quality of dental implants. Laser treatment of heart disease: The heart disease patients have blocked blood due to the deposition of cholesterol or calcium crystals in the arterial blood vessels, so that the myocardium cannot obtain the oxygen-rich blood necessary for metabolism, which makes the myocardial ischemia, infarction and necrosis.
Existing treatment methods include internal medicine treatment and surgical treatment. Surgical operations are coronary artery bypass and balloon angiogenesis. The former is to remove a segment of the venous blood vessel of the human lower limb and transplant it to the bridge between the heart aorta and the narrowed blood vessel; the latter Then, the empty micro-shaped balloon is slowly pushed through the venous tube to the place where the coronary artery has been blocked, and then the balloon is inflated to push the blood spot to the artery wall to restore blood circulation. These two technologies have been clinically applied in hospitals at home and abroad, but some patients are not suitable for the above treatment. Therefore, in the past 10 years, there have been fiber optic laser beams into the arterial tube to "perforate" the blocked site to form blood vessels or to ablate intravascular thrombosis. technology. Later, it was further developed into a vascular reconstruction technique for coronary heart disease. The laser directly perforated the left ventricular wall, "reconstructing" dozens of vascular channels with a diameter of 1 mm, and allowing the oxygen-rich blood of the left ventricle to flow directly through the reconstruction In the blood vessel, directly improve the blood supply in the ischemic area. There is also a combination of the above two technologies. For example, in 1996, in Beijing General Hospital of Posts and Telecommunications, a 47-year-old coronary heart patient underwent a "perforation + bypass" operation. The postoperative symptoms were eliminated and the cardiac function was significantly improved. Two weeks He recovered and was discharged.
Laser treatment of cancer: When the human body is diagnosed with a malignant tumor (cancer), one of the traditional treatment methods is to inject radioactive chemicals and kill the cancer cells with radioactive rays. The disadvantage is that the good tissue cells around the tumor are also killed together died. The laser scalpel is now used to directly remove the tumor, and laser dynamic therapy can also be used. The patient is first injected with a "hematoporphyrin derivative" photosensitive drug, which has a strong affinity for cancer cells and a weak affinity for normal cells. After 12-24 hours, the drug will adhere to the tumor. At this time, a laser output from an excimer laser is used to enter the tumor site through an extremely thin optical fiber. When the laser encounters the drug, it is absorbed and causes the photochemical reaction of the drug to produce Singlet oxygen causes a strong oxidative reaction in the cells in contact with the tissue, breaking the biomolecule chain, that is, cutting off the tumor's blood supply and splitting it into fragments for gasification. This therapy can also be applied to the treatment of cervical cancer, bladder cancer, esophageal cancer, rectal cancer and bronchial cancer in gynecology, with a success rate of 70% -80%. This medical law was adopted in about 400 hospitals in the United States in 1996, and treated about 1.3 million people annually. In addition, it can also be used for laser dynamics for cancer examination. According to the hematoporphyrin derivative, it will emit orange-red fluorescence under the laser irradiation, so after the patient is injected with this medicine, the human body is scanned with the laser of the appropriate wavelength. Observe whether there is orange-red fluorescence through a speculum. If there is orange-red, it means that there are cancer cells in this part. This test has high reliability.
Laser Beauty: For a long time, people have hoped that the wrinkles, scars, warts, moles and other defects on the facial skin can be truly eliminated to improve the beauty of the facial shape. Traditional medical methods are various, some of which are not obvious and some are worse. In the 1980s, the United States and Australia successively adopted laser beauty. The cause of wrinkles is that the skin surface collagen becomes longer or broken, causing the skin folds to lose their elasticity. Generally, pulsed CO2 high-energy laser irradiation can eliminate the very thin outer skin that produces defects and shorten the length of the surface collagen1 / 3, restore skin elasticity, repair scars, and make collagen fragments heated and melted together to form new collagen and reshape the outer skin layer. In a clinical trial of 900 people, 90% of them eliminated 75% of wrinkles on their faces. At present, some medical institutions in cities and towns in China have this kind of beauty clinic. This kind of beauty clinic uses dermatology laser equipment to treat nevus, scarlet spot, hemangioma, birthmark, freckles, wrinkle removal, tattoo removal, tattoos, eyebrows and lines. Eyeliner, hirsutism, etc., can be safe and reliable, agile beauty, no sequelae. The application of laser technology in medicine also includes laser technology in the treatment of gallstones, orthopedics, gynecology, gastrointestinal tract and laser sterilization, etc., and has constantly updated application results and development. In addition, laser devices and various types of laser-specific or multi-purpose medical equipment are also developing rapidly.
3. Application and development prospects of high-power lasers The application of high-power lasers in medicine is very common. From the gasification of various warts, moles, neoplasms and benign and malignant tumors on the body surface, to the treatment of internal cavity diseases. From the earliest carbon dioxide and Nd: YAG lasers to excimer lasers, high-energy super-pulse carbon dioxide lasers, Q-switched emeralds, HO: YAG lasers and high-power semiconductor lasers, lasers are gradually becoming smaller and lighter. Flexible optical fiber can selectively output higher power laser. In particular, the HO: YAG and high-power semiconductor lasers that have appeared in recent years have made major advances in laser surgery technology and are widely used in many fields such as general surgery, urology, gynecology, and otolaryngology. HO: YAG-mid-infrared laser wavelength is about 2.15μm, pulse energy can reach 0.5-2.8J / pulse, pulse frequency 5-40 times / s, average power 1.25-80W. Human tissue water absorption has two sharp absorption peaks near the 2.0 and 3.0 μm spectral wavelengths. When this band interacts with tissue, light is easily absorbed by body fluids and has a small thermal diffusion effect on adjacent tissues, which is less than that of other visible and near-infrared lasers. The thermal damage is small, and the absorption point of light is strong. It has been successfully used in various endoscopic operations: laryngoscopy for vocal cord polyps, fiberoptic bronchoscopy for lung cancer, esophagus, stomach and enteroscopy for polyps and malignant tumors, and laparoscopic treatment for ovarian cysts and endometrial displacement Symptoms, under the cystoscope, ureteroscope, prostate hypertrophy, lithotripsy, bladder cancer and other operations. Its gasification cutting effect is better than Nd: YAG laser. Semiconductor lasers. The early semiconductor lasers were limited because they could not output high power. The key lies in the production technology of miniature high-power semiconductor chips.
With the emergence of high-power semiconductor laser array technology, compatible optical fibers, and precision control technology for parameter calculation, the prospects of medical multi-disciplinary applications are very promising. The 805nm gallium aluminum arsenide semiconductor laser developed by the United Kingdom does not require water cooling and has a small volume, which can simultaneously perform gasification and solidification. There are five working modes: contact surgery, which is very suitable for minimally invasive surgery under endoscopy, such as bladder tumor, prostate resection, uvula, and nasal polyps; non-contact surgery, mainly through its pulse mode and thermal effect Perform orthopedic surgery, including arthroscopic surgery, discectomy, etc .; insertion or photocoagulation surgery, the laser beam penetrates into the tissue from the probe at the end of the fiber, from longitudinal conduction to radial scattering, which causes the surrounding tissue to heat up, causing degeneration and coagulation Necrosis, used for tumor treatment; photodynamic therapy, with the development and use of new photosensitizers, the semiconductor laser with a wavelength of 630-980nm is extremely effective for photodynamic therapy; tissue welding, the semiconductor laser with a wavelength of 808nm produces less damage , There is selective tissue reaction, so that tissue adhesion. Semiconductor laser, biological effect is between Nd: YAG and HO: YAG, gasification effect is better than Nd: YAG laser, coagulation and hemostatic effect is better than HO: YAG laser, the development prospect is very broad.
Hangzhou Xinlili Optoelectronics Technology Co., Ltd. (http: //) is a comprehensive technology service company specializing in the application development, marketing and technical services of lasers, spectroscopy, optical components, optical and electromechanical products, and providing customization and system integration. We focus on optoelectronic technology and work with you to promote the rapid development of the optoelectronic industry. Supported by Newopto.com
Backpacks For School,Kids Backpack,Childrens Backpack,Childrens Rucksack
Ningbo Happiness Stationery Industrial & Trading Co Ltd , https://www.nbcnhappiness.com