What harm does X-ray and lead radiation do to human body?

According to the latest research report published by British researchers, X-ray scanning and CT examination, which are commonly used in hospitals to diagnose diseases, may be the cause of cancer in some people. In Japan, where X-ray and CT examinations are common, 3.2% of the new cancer cases are caused by these two examinations every year (for related reports, see February 1 edition of Metropolitan Express). In fact, it has become an indisputable fact that radiation in X-ray and ct examination is harmful to human body. For a long time, scientists have been more concerned about how harmful it is to the human body to do such a physical examination. Metropolitan Express Fu Ling ■ Survey: 90% of Hangzhou people don't mind checking. Yesterday, the reporter interviewed 20 citizens randomly in the Provincial People's Hospital, the youngest being 34 years old and the oldest being 72 years old. They either had an X-ray or CT examination when they went to the hospital, or had a chest X-ray examination during the physical examination, which means that all the interviewees received X-ray radiation without exception. The reporter designed two questions: First, do you know that X-rays may cause cancer? The second is whether you have doubts about the examination because of the harm of X-rays to human body. The survey found that, except for a 57-year-old aunt who had never heard of "X-ray may cause cancer", all other 19 citizens said they had heard of it. Qu, 68, said with great certainty: "Radiation, like the atomic bomb explosion in Guang Chen, will cause leukemia." However, the awareness of X-ray injuries did not prevent most citizens from receiving medical examinations. Some 18 citizens think that the hospital's inspection equipment has undergone strict inspection, and doctors know that they will not mess around, so they are very relieved; But the other two said they would feel a little uncomfortable when they were examined. Especially if the results of the first examination are not satisfactory, you will feel that the doctor has not done his duty. ■X-ray and CT examination of cancer probability. What are the chances of encountering radiation? Although X-rays contain harmful radiation, when the superficial symptoms of patients are not enough to diagnose the disease, or the degree of the disease needs to be further determined, X-rays and CT examination are needed to help doctors make a definite diagnosis. X-ray examination of fracture is the most common, in addition, abnormal conditions of lung, liver, kidney, spleen and other internal organs can be observed; Bone tumors such as ribs, clavicle and thoracic vertebrae; Mucosal swelling and tumors caused by gastric ulcer and gastroenteritis can also be found. The principle of CT examination and X-ray is basically the same. The difference is that the X-ray film takes a plane image of the human body, so the internal organs will be overlapped before and after; The CT adopts the method of tomography, just like cutting bread, taking different photos of the examined parts of the body from different points, thus solving some overlapping problems. Generally speaking, X-ray films of diseases such as fractures can be seen clearly, but diseases involving intracranial tumors, liver tumors and other complicated structures need CT. How do X-rays and CT cause diseases? Medical X-ray and CT examination are the biggest artificial radiation sources that people may come into contact with at present, which can penetrate cells, destroy DNA and even induce some cancer cells. Gofman, an internationally renowned radiologist, found that X-rays will destroy the internal structure of cells and cause irreparable lifelong damage to genetic molecules: about two-thirds of the 6,543,800+8,000 breast cancer patients diagnosed in the United States each year are related to medical X-rays. Other studies have shown that X-rays can destroy red blood cells and may induce leukemia and other blood diseases. Professor burlington de Gonzá lez of Oxford University in England said: "Among men, the most dangerous disease related to X-rays is bladder cancer, partly because many different kinds of X-rays can irradiate the bladder. Women have a higher risk of lung cancer and colon cancer. " Hypothetical case-cancer risk of patients with rib fracture-how many X-rays do patients with fracture need? Xia Bing, director of the Department of Orthopaedics, Zhejiang People's Hospital, calculated as follows: once at the time of diagnosis (if further diagnosis is needed, CT scan will be added, and X-ray radiation will also be encountered), once after surgery (patients with joint reduction need to do it again during surgery), once a month after surgery and once every three months after surgery. This is the basic number of exams, ranging from 6 to 4. In the future, it depends on the different rehabilitation conditions of fracture patients, whether the film is clear and needs to be redone, referral from higher and lower hospitals and other factors. Some patients can do 10 times at least. Suppose a patient with a broken rib is examined six times during the course of seeing a doctor, then how much cancer risk will he face? Take a chest X-ray. When radiation is irradiated on the inspection area, the irradiation rate is about 160 millisieverts/hour (millisieverts are the unit for measuring radiation), which is about 0.045 millisieverts/second. In the First People's Hospital of Hangzhou, it takes about 0.5 seconds to take a chest X-ray, which means that the patient has to bear about 0.023 millisieverts of radiation. According to the standards formulated by the International Commission on Radiological Protection, the total radiation risk is 0.0 165/ sievert, that is to say, the probability of cancer will increase by 0.0 1 65 for each dose of radiation received by the human body (1sievert = 1000 millisieverts). Based on this calculation, the risk of a patient with rib fracture will increase by about 3.8/10 million. For other medical examinations, generally speaking, X-ray examination of limbs requires 0.0 1 msv, abdomen 0.54 msv, pelvis 0.66 msv, lumbar spine10.4 msv, and upper digestive tract 2.55 msv. Based on this calculation, the risk of cancer in healthy people due to physical examination is between one in ten thousand and one in one in one hundred thousand. To be sure, the radiation inspection that can be omitted should be omitted. ■ Safe distance of self-prevention —— People don't have to refuse the necessary X-ray and CT examination because of radiation of more than two meters, but Professor Zhang, chairman of Zhejiang Radiology Society, director of Radiology Department of Run Hospital and doctoral supervisor, still reminds patients' families that patients who don't need special care don't have to accompany the examination, and there is no need to be exposed to radiation at all. However, there is no need to even dare not enter the radiology department of the hospital for this reason. When taking chest radiographs, the X-ray exposure rate in the examination area is about 160 millisieverts/hour, and it is 80 millisieverts/hour at two meters, which is about 1/2000 at the center. The probability of cancer at this time is about one in a million. The radiation at a distance of 6 meters from the central point is 1.5 microsieverts/hour, which is about one millionth of the central point, and the probability of cancer is even smaller. Vulnerable groups-pregnant women and newborns, although X-ray and CT examination during pregnancy will not necessarily lead to fetal malformation, Chen Wenhui, chairman of Clinical Radiology and Intervention Branch of Hangzhou Medical Association and director of Radiology Department of Hangzhou First Hospital, suggested that pregnant women should try to avoid such examination, especially expectant mothers in the first three months of pregnancy. Because this is a critical period for the formation of important fetal organs, X-rays may mutate these undeveloped cells and tissues, and the incidence of fetal congenital malformation will also increase. Another study shows that if the newborn is examined by CT because of head injury, it will have some influence on the later learning ability and logical reasoning ability, but it has no influence on the spatial recognition ability. Sensitive parts-gonads Cells in different parts of the human body have different degrees of response to X-rays, among which gonads are the most sensitive. Professor Zhang said that foreign hospitals have done a good job in this regard. When the patient's lower abdomen is examined by X-ray or CT, the gonad will be covered with lead sheath or other protective materials to improve the safety factor. Most hospitals in China do not have such protective measures. Responsible postdoctoral British researchers found that in the past 20 years, 15 countries, including Japan, showed an upward trend, and at least 30% of them were unnecessary. Professor Zheng from the Institute of Radiation Protection and Nuclear Safety Medicine of China Center for Disease Control and Prevention also pointed out that medical staff should not neglect the protection of patients and subjects just because they come to the hospital for examination once. Subjects should also have a sense of self-protection and refuse unreasonable medical irradiation. ■ Eat more kelp when it comes to diet and health care, Director Chen Hui, who has been in the business for 20 years, shook his head and said "no" twice, and then added with some hesitation: "Eating more iodine-containing things like kelp may be useful and can absorb some rays." ■ The latest spiral CT will be launched in Shaw Hospital next week, and the latest model of 16-slice spiral CT in Asia will be officially launched in Shaw Hospital. This new type of CT, costing 900,000 US dollars, has only 8 sets installed in hospitals around the world. It can scan the parts to be inspected within 0.37 seconds and get 16 images taken at different positions. These two days, the professor is working with colleagues to study how to exert the maximum power of the new CT. After nearly 40 years in the business, he has accepted countless new technological innovations. From 65438 to 0975, CT examination was officially used in clinic. Shortly thereafter, as the first generation CT person in China, Professor Zhang went to Germany to study how to use this new instrument for half a year. At that time, the X-ray examination, which had a history of nearly 80 years, was no longer the kind of instrument that took half an hour to make a film. In less than 30 years, CT technology has also advanced by leaps and bounds. It takes 4-5 minutes for the first generation CT machine to complete a scan; The second-generation CT machine product consisting of two X-ray tubes only needs 30- 120 seconds for each scan; The third-generation CT machine product is composed of multiple X-ray tubes, and it takes 2.5 seconds to complete a scan. By the fourth generation CT machine, the scanning time was shortened to only 1 second. And since then, all kinds of new CT machines have controlled the time within 1 second. Similarly, the speed of X-ray examination is increasing rapidly. At present, an ordinary chest X-ray imaging only needs 0. 1 sec, and other parts generally need 0.5 sec. X-ray and CT imaging, from the initial film projection to computer imaging, has moved towards the most fashionable digital age. Modern X-ray and CT inspection machines advocate sensitive digital receivers. Professor Zhang said confidently: "Sensitive receptors and rapidly increasing imaging speed mean less radiation and safer examination for patients."