-What is the strength of a medical magnetic field? More than how much is harmful to the human body?

Electromagnetic radiation; harm; protection Modern large and medium-sized hospitals are equipped with CT, magnetic *** vibration (MRI), X-ray machines, medical gas pedal and other large medical equipment, thousands of varieties, worth hundreds of millions of dollars. Due to the complex structure and principles of medical instruments, involving sound, light, electricity, gas, magnetism and other technical fields; and almost all by electronic elements, components, so they are strong or weak electromagnetic radiation. Thus, hospitals not only have to face the deteriorating natural electromagnetic environment, but also superimposed on the electromagnetic pollution of medical instruments. In recent years, the hospital area more quickly appeared electromagnetic environment complexity, electromagnetic spectrum congestion, electromagnetic interference serious problems. Increasingly serious deterioration of the electromagnetic environment, not only harm to the human body, but also to the medical instrumentation will produce serious interference, its electronic and electrical systems. At present, the medical instrument anti-interference, radiation and electromagnetic pollution has been exceptionally prominent, which should be carried out harm and protection, planning and management, design and implementation of multi-level research work. First, the phenomenon of electromagnetic radiation of medical instruments The so-called electromagnetic radiation of medical instruments refers to in addition to the traditional X-ray radiation, equipment generated electromagnetic energy (or weak electromagnetic field). From the technical principle, where the medical instruments are energized, according to the law of electromagnetic induction will be strong or weak electromagnetic radiation phenomenon, and the higher the frequency the more serious. Some people call the electromagnetic pollution generated by electromagnetic waves as "electronic smog". 1. Electromagnetic pulse Lightning and nuclear explosions produce the most typical electromagnetic pulse, and large-scale medical equipment such as MRI, CT, gas pedal, laser generator, etc., due to the large, instantaneous current through, which is accompanied by electromagnetic pulse generation. 2. 2. electromagnetic leakage of modern medical equipment, a considerable part of the use of computer-controlled technology, the computer's broadband digital signals by connecting wires, keyboards, printers and other parts, or by the control of the host device, such as CT scanner frame, MR gradient RF cabinets and other parts of radiation leakage. 3. electromagnetic noise. 3. Electromagnetic noise Another part of electromagnetic radiation is often referred to as the electromagnetic noise of medical equipment, which mainly includes power distribution transmission line corona noise, contactor coil charged with its own noise and contact opening and closing of the discharge caused by the noise, and magnetic *** vibration radio frequency noise and excimer laser noise. 4. Industrial frequency electric field interference Large medical equipment power, high voltage, especially X-ray machine type equipment, the preparatory state and excited state power difference is very large, resulting in instantaneous switching of the power supply line current, resulting in industrial frequency electromagnetic interference. Second, the impact of electromagnetic pollution on medical instruments Due to the individual medical instruments in the external electromagnetic radiation at the same time, itself is also subject to foreign electromagnetic radiation interference, so at the same time with the source of interference and the interference body of the duality. Although electromagnetic pulse can not directly kill or injure the human body, but high-intensity electromagnetic pulse can massively damage medical equipment, lightning damage to equipment is a typical example. Electromagnetic pulse can not only massively damage the electrical components, strong electromagnetic pulse can also make the optical fiber heat, causing mechanical deformation, directly affecting the transmission characteristics of optical fibers, the use of high-tech other equipment also poses a threat. Medical instruments electromagnetic radiation of mutual interference, it is possible to make the relevant circuit potential increases, if the external potential to ground more than 5V, it is possible to make the computer control system commands to produce false action, or make the complex control circuit logic confusion, MRI, CT image artifacts are sometimes caused by this aspect of the reason. In hospitals using a large number of cell phones, will make the MRI image deformation, intelligent infusion pump error, electroencephalogram waveform abnormalities have been confirmed, and medical instruments electromagnetic interference with each other is also the same can not be ignored. Third, the harm of electromagnetic pollution of medical instruments on the human body Many authoritative research organizations in the world have confirmed the impact of electromagnetic waves on the human body. Different spectrum, intensity and dose of electromagnetic waves on different parts of the human body, organs and tissues and to the cellular and molecular levels with physical, chemical and biological effects, and in the physiological and psychological are induced by non-negligible response. Medical instruments produce a high density, low intensity electromagnetic waves. Low-intensity, prolonged electromagnetic radiation does not translate into appreciable heat in living organisms, but produces a range of non-thermal biological effects and tends to exhibit frequency selectivity and power selectivity. Non-thermal biological effects tend to occur far from equilibrium. The response of organisms to electromagnetic waves is nonlinear, and the induction of small amounts of energy from outside can release large amounts of energy within the organism. The biological effects occur mainly in the cell membrane. The organism, under the action of the pulsed field, can cause the cell membrane to produce a new transmembrane potential on the basis of the original electrostatic potential. It directly affects the enzyme activity of the cell, makes chromosome aberrations, and changes the structure and function of the cell. Recently, foreign literature reports that living in a low-frequency magnetic field environment above 0.2μT will have a harmful effect on the human body. 1. Harmful effects of high-frequency electromagnetic waves Electromagnetic radiation produced by high-frequency electromagnetic waves has high energy. For example, the magnetic **** vibration of the radio frequency system, gradient system, CT and X-ray machine in the high-voltage generation system, medical gas pedal in the microwave system and so on. Electromagnetic pollution by high-frequency electromagnetic waves is a phenomenon of ionic radiation, the effects of which can cause serious harm to various living tissues and genetic material, and in severe cases can lead to burns and tumor formation. As early as the early 1960s, a journalist and a couple of scientists had already alerted the American public to the harmful effects of microwaves emitted by high-voltage cables.More than 20 years later, the first epidemiologic study on the carcinogenicity of the electric power grid was published. Its authors, writing in the American Journal of Epidemiology, said that children living near power grids had a 1.6 to 2.2 times higher incidence of early childhood leukemia than other children.In March 2001, the UK's National Council on Radiological Protection (NCRP) published a study. The report's author, epidemiologist Richard Doyle, noted that "prolonged high-frequency motion of electromagnetic fields increases the risk of malignant tumor formation in children." The likelihood of disease is greater if children live in the range of magnetic fields with strengths of 0.4μT or greater intensity. Doyle estimated that every year in the United Kingdom appeared in 500 cases of early childhood leukemia, there are 2 cases related to "electronic smoke". 2. Hazards of low-frequency electromagnetic waves low-frequency electromagnetic waves generated by electromagnetic pollution on the human body is relatively small, but has a certain long-lasting, is considered a non-ionizing radiation. Scientists on medical magnetic **** vibration and other frequencies below 3kHz electromagnetic field research shows that non-ionizing radiation on the biological is a negative effect. Low-frequency electromagnetic waves can penetrate deep inside the body's organs and generate heat by absorbing energy from the tissues; this leads to palpitations, insomnia, sweating, fatigue, and a host of other adverse reactions in people who are allergic to electromagnetism. There are indications that placing animals within the range of electromagnetic fields above a certain intensity for a long period of time accelerates the generation of cancer cells, disrupts electrophysiology, changes neuron function, and harms the follicular sac. Fourth, countermeasures and thinking Medical instruments play a positive role in treating the sick to save people, at the same time, its electromagnetic pollution in a certain way silently infested human health. Modern hospitals have introduced magnetic **** vibration systems with increasingly high magnetic field strengths, and 1.5T MRIs are widely used in clinical practice, improving imaging quality and speed and developing new functions. However, how does MRI's powerful homogeneous magnetic field, alternating gradient magnetic field, and high-power radiofrequency system affect patients and operators? In particular, how much physiological and psychological harm will be caused to the relevant medical staff working in the range of strong magnetic fields (MRI operating tables are mostly within 1G lines) for a long period of time? Similar to this question in the hospital is a lot, just many large-scale medical instruments into the clinical application of time is not long enough, the harm and negative effects of people have been recognized, but there is still a lack of quantitative description, but also a lack of time to verify. For the electromagnetic pollution of modern medical instruments, based on existing conditions, the countermeasures that can be taken are three aspects: First, strengthen the product hazardous experiments, the effective implementation of measurement and quality control. The second is the machine room protection, in addition to the product to install the necessary self-shielding facilities, the protection of the machine room must not be lower than the manufacturer's protection standards (especially MRI, gas pedal, etc.). Conditional hospitals to monitor electromagnetic pollution, and combined with the actual proposal for new protection standards. Third, the staff to strengthen the awareness of self-protection, like recognizing the hazards of radioactivity, and gradually recognize the "electronic smoke". It is recommended that the relevant departments and personnel to study the topic, the development of an electronic protective clothing, to protect the health of the majority of medical workers. Considering the mutual interference between medical instruments, in order not to cause performance degradation or malfunction due to electromagnetic radiation interference, we should: First, on the basis of economic and reasonable, put forward standards and norms to limit, and reduce unnecessary radiation as far as possible. Second, according to the characteristics of various types of medical instruments, integrated planning, rational layout, to determine the location of installation and placement. So that each instrument in the same space at the same time when working, each other does not affect or have minimal impact. Third, if necessary, install electromagnetic shielding and radio frequency shielding. In short, in addition to X-ray hazards of medical instruments, the hazards of electromagnetic radiation objectively exists, we need to have a correct understanding of this, but there is no need to panic too much. This paper raises this issue, is to better *** with to recognize it, study it, and take the necessary measures to be reasonably protected.