With the harm of radiation and the rapid development of modern society, people can easily feel some benefits brought by high technology in their lives, but the subject is a double-edged sword, which has both advantages and disadvantages. So do you know how harmful this radiation is?
Harm of radiation 1 When the unstable elements of radiation decay, the penetrating particle beam emitted by the nucleus can be divided into class A rays, class B rays and class C rays, among which class C rays have the strongest penetrating ability. In addition, radiation is harmful to the environment and human body. As we all know, radiation and radioactive substances are harmful. What are the hazards to the human body?
The human body is exposed to radiation, and with the increase of radiation dose, some harmful effects may appear at random. For example, it may induce malignant tumors such as leukemia, thyroid cancer and bone tumor; It may also cause gene mutation and chromosome aberration in human genetic material, leading to congenital malformation, abortion, stillbirth, infertility and other diseases. However, the probability of this happening is very low. At present, the risk is generally not beyond the acceptable range.
Once an accident happens, if the radiation dose received by the human body reaches a certain level, there may be some clear and expected harmful effects. For example, if the lens of the human eye is irradiated by X or γ rays exceeding 2 Gy at a time, lens opacity may occur after 3 weeks, resulting in cataract; Exposure of human skin to different doses of radiation will cause hair loss, erythema, blisters, ulcer necrosis and other injuries. In addition, it may also cause anemia, decreased immune function, shortened life expectancy and endocrine and reproductive dysfunction.
When the human body is exposed to a dose greater than 1 Gy in a short time (from a few seconds to a few days), it will produce acute radiation sickness, which is life-threatening; Chronic radiation sickness may be caused by long-term exposure of the body to radiation exceeding the dose limit, resulting in chronic radiation damage of the whole body, mainly hematopoietic tissue damage. This situation is mainly aimed at professionals engaged in radiation work, and rarely happens in the public, excluding local medical irradiation.
Of course, radiation can also benefit mankind. Radiation used in hospitals is often used for the diagnosis and treatment of some diseases in human body, which can play a unique role. At the same time, it is widely used in industry and agriculture, scientific research and national defense construction. Our key is scientific use and strict protection to protect human body from its harm.
Overview of radiation hazards II
X-ray has the characteristics of short wavelength, strong penetration, fluorescence, photographic function and biological utility. Through fluoroscopy, photography, irradiation and other means, the internal organs of the human body are diagnosed and treated. The biological effects of X-rays absorbed after being injected into human body are harmful to human body, and the degree of damage depends on the absorbed dose. Generally speaking, too small dose is not harmful to human body, while too large dose will lead to the destruction of tissues and cells and the pathological changes of blood system.
Chest X-ray is a commonly used radiological examination method, which makes use of the characteristics of X-ray penetration, fluorescence and photographic effect. When X-rays penetrate different tissues of human body, the absorption degree is different, and the amount of X-rays reaching the screen is also different, forming different images of black and white contrast, which provides basis for doctors' diagnosis. Chest X-ray examination usually takes tens of seconds, which has limited harm to human body. Adults do chest X-ray once or twice a year, and there is almost no obvious harm. However, because children are at the peak of growth and development, cell division is active, which is much more sensitive than adults, and the younger they are, the more sensitive they are (embryonic tissues are more sensitive to radiation), which will cause some somatic cells to be damaged. If these damaged cells fail to repair themselves (or repair abnormally), they will stay in the body, like a "time bomb", and start to replicate wildly and become cancer foci under the condition of low immunity or cancer-promoting factors. Therefore, the more radiological examinations, the greater the probability of inducing cancer. In the decades after radiological examination, it may induce a far-reaching effect.
trait
When the lead chamber containing radioisotopes is opened, a beam of rays will be emitted from the lead chamber immediately. When the magnetic field is added, the radiation is divided into three beams, among which the beam with smaller deflection angle is called α-ray, the other beam with larger deflection angle is called β-ray and the middle beam is called γ-ray. The penetration ability of alpha rays is the weakest, and a thick paper can block it; The penetration ability of beta rays is stronger, and plexiglass with a certain thickness can also block it; Gamma rays are very penetrating and can usually be blocked by lead plates. In addition to these three kinds of radiation, commonly used rays include X-rays and neutron rays, each of which has a specific energy, and has different penetration and separation capabilities for substances, thus causing some physical, chemical and biochemical changes in substances or organisms. If the human body is exposed to large doses of radiation for a long time, it will damage cells, organs and tissues, destroy the molecular structure of human DNA, and sometimes even lead to cancer or genetic defects in the next generation. People exposed to radiation often have headaches, limb weakness, anemia and other symptoms, and even death.
The radiation emitted by radioisotopes is a special invisible and intangible substance, so some people compare it to "Moline". How to protect it and reduce the harm of radiation? All practical activities using ionizing radiation sources must abide by three principles of radiation protection, namely:
First, the practice is justified;
Second, protection optimization;
Third, personal dose limit.
prevent
There are three basic radiation protection methods:
First, time protection;
Second, distance prevention;
Third, shielding protection.
It is worth noting that doctors should weigh the advantages and disadvantages according to the actual needs of patients when using X-ray equipment to diagnose and treat patients, so as to use X-ray equipment safely and reasonably. And patiently persuade those patients who voluntarily ask for treatment but don't need to use X-ray equipment to guide them out of the misunderstanding. There is no need to use advanced medical equipment to treat all diseases. In addition, with the warming of people's beautification and decoration of rooms, the pollution of rooms is also increasing. One of the reasons is the polluted air released by some building materials, but as long as our rooms are often ventilated, we can reduce pollution, seek advantages and avoid disadvantages, and let radioisotopes and radiation devices benefit mankind.
Harm of radiation 3 X-rays "trigger" diseases, but more often "cure" diseases.
Wang Cunbo, deputy chief physician of the Third Department of Imaging, Penglai People's Hospital, said that generally speaking, every time an X-ray is taken, the human body will receive about 0.02 millisieverts of radiation. How much radiation can the human body actually bear? Scientific research shows that the acceptable radiation dose for human body is no more than 200 millisieverts a year. Of course, everyone's physique and resistance will be different. In addition, in the relevant regulations of our country, the upper limit of acceptable annual radiation for human body is only 50 millisieverts, which is less harmful to human health. What's more, radiation is everywhere in our lives. Even in the sun, watching TV, flying, and even the air we breathe and the food we eat every day, there is radiation, but the amount is very small and will not cause harm to the human body, so people do not feel it.
Normal X-ray examination does little harm to the body.
Take x-rays as an example. Now the amount of radiation you take each time is about 0.02 millisieverts. In fact, this is equivalent to watching TV or computer for 2 hours every day and accumulating "eating" radiation for 4 to 6 months, which has little effect on the body. Generally speaking, there are two kinds of radiation in medical examination: one is radiation in images, such as taking X-rays and doing CT. This kind of radiation is directional and controllable, which basically ensures that only the inspected part will have radiation, and the radiation dose is quite small. The other is the radiation in nuclear medical examination, which has no directionality and will last for a long time, but it has been controlled after taking measures.
Correctly understand that X-ray examination should not be more than once a year. Of course, we should pay attention to the cumulative benefits of X-rays and try to avoid too frequent and long-term X-ray examinations. The National Health Planning Commission clearly stipulates that the frequency and dose of radiation examination should be strictly controlled in health examination. Generally, each person does not use radiological examination technology more than 1 time in health examination every year.