Overview X-ray is an electromagnetic wave with a short wavelength and strong penetrating ability. It can pass through human tissues, causing physical and biochemical changes in body fluids and tissue cells, resulting in various degrees of damage. The amount of radiation from different X-rays that irradiates the human body each time is small, but it can easily damage germ cells and chromosomes in the body. The medical term X-ray refers to any method of X-ray examination that uses X-rays to visualize or photograph the inside of the human body, and is based on the principle of penetrating X-rays. X-rays are emitted from the X-ray tube of a light source. When it penetrates the human body, it is absorbed by the calcium-containing components of bone and water (blood, etc.). Water (blood, etc.). Soft tissues (muscles) are absorbed and weakened. The image that is absorbed with different intensity is an X-ray film, and reading the images of organs and tissues based on this different intensity is called X-ray photo reading. Types of photographic methods are simple photography and contrast photography, CT examination is one of the X-ray examination methods, electronic computed tomography, is the use of electronic computers to analyze X-rays, called CT scanning, is a special type of X-ray examination, many researchers believe that CT scanning accepts lower rays than normal X-rays. MRI is called Magnetic Resonance Imaging and has not been documented to cause significant damage to the human body, except for possible (note possible) effects on pregnant women. There is no free radiation damage to the human body, and there are no reports of the examination being harmful to the fetus. According to available information at home and abroad. The unit of X-ray radiation is roentgen and the unit of absorbed dose is rad/hour. When the amount of radiation is 1 roentgen, the absorbed dose is approximated as 1 rad, and the dose equivalent is approximated as 1 rem (0.01 sievert). The names of the units used in various sources about how much X-ray radiation is used are inconsistent and confusing to read. The good thing is that all three values are approximately equal, and below I uniformly use the X-ray radiation dose —– roentgens (rads) and millirems. (1 roentgen = 1000 millirems.) Some chronic irradiation damage occurs when the cumulative dose of absorbed dose reaches a certain level. Absorbed doses of 100-200 rads (roentgens) harm the hematopoietic system , causing moderate leukopenia and vomiting. Absorbed doses of 200-600 rads (roentgens) can cause severe leukopenia, bleeding infections, purple scarring, and hair loss. The effect of X-rays on the fetus is mainly related to the following two factors: (1) Related to the irradiation dose: Studies have confirmed that pregnant women 6 to 8 weeks after conception who receive 42 to 60 roentgens (rad) of X-rays radiation will cause changes in the structure of the embryonic genes or breaks in the chromosomes, which will result in fetal malformations or even fetal death. It is generally believed that the X-ray dose absorbed by the fetus in the first four months of pregnancy is more than 10 roentgens (rads) (equivalent to 10 chest X-ray doses), which is prone to cause malformations. The International Commission on Radiological Protection (ICRP) is of the opinion that if an X-ray dose of more than 10 roentgens (rads) is received during the entire pregnancy, the pregnancy must be terminated. Some scholars have also suggested that the minimum amount of fetal damage is 2 roentgens (rad). x-ray if direct irradiation of the uterus, the radiation dose exceeds 6 roentgens (rad), will increase the incidence of congenital cataracts in the fetus. (2) Related to the irradiation site: irradiation in the chest, hands and feet and other parts of the body away from the fetus is better than the abdomen, pelvis and other parts of the body close to the fetus. The Ministry of Health clearly requires that women of childbearing age 8-15 weeks after conception should not be subjected to lower abdominal radiography, and try to take chest X-ray photography. After the third month of pregnancy, most of the organs of the fetus have basically formed, X-ray examination of the fetus, although less harmful, but also affect the continued development of fetal gonads, teeth and the central nervous system, so that the fetus in the womb to develop slowly, after birth mental retardation. At the end of pregnancy, the development of fetal organs is basically mature, so it is not harmful to receive X-ray examination at this time. In addition, relevant experts also pointed out that early fetal X-ray irradiation may also increase the risk of malignant tumors and blood cancers within 10 years of age. Women of childbearing age should not undergo X-ray examination before menstruation. This is because women of childbearing age are in the stage of ovulation before menstruation, and it may also be the early stage of fertilization and pregnancy, if they receive X-ray irradiation at this time, it may cause damage or even death to their egg cells or fertilized eggs. Therefore, some countries’ health departments have now clearly stipulated that women of childbearing age must undergo X-ray examination within 10 days after menstruation. Irradiation dose of general X-ray examination Chest X-ray 0.1-0.2 roentgen (rad); Gastrointestinal fluoroscopy 3-3.5 roentgen (rad); Pelvic photograph 1-3 roentgen (rad). Lung fluoroscopy 0.05-0.1 roentgens (rads)/times Dental radiography 5 roentgens (rads)/times Gastrointestinal system 30 roentgens (rads) Oncology treatment (localized irradiation) 3,000-7,000 roentgens (rads) Head 0.04 roentgens (rads) Abdomen 0.245 roentgens (rads) Intravenous pyelograms 1.398 roentgens (rads) During a single x-ray examination of a pregnant woman, the fetus receives an When a pregnant woman receives an X-ray examination, the fetus receives an X-ray dose of 0.07 roentgens (rads) The irradiation dose of a general CT examination: Head 0.05 roentgens (rads) Chest 0.1 roentgens (rads) Abdomen 2.6 roentgens (rads) Lumbar vertebrae 3.5 roentgens (rads) Pelvis 0.25 roentgens (rads) Nowadays, there are some people who think that X-ray fluoroscopy of the chest during pregnancy or radiographs can induce fetal malformations. In fact, this practice is unfounded. It has been reported that 20 chest X-rays during pregnancy are associated with a fetal malformation rate of 1 per 1,000. This figure is far less than the general incidence of fetal malformations (3%). Thus, it can be seen that the occasional one or two X-ray chest X-ray or filming during pregnancy will not increase the incidence of fetal malformations, especially after the third trimester of pregnancy, the likelihood of malformations is even smaller. There are even some people who believe that a pregnant woman herself being in the room where the X-ray examination is taking place will adversely affect the fetus, even if she herself is not doing the X-ray irradiation examination. China’s X-ray radiation protection measures are clearly stipulated: in the X-ray machine components, in addition to the X-ray tube, other than the X-ray tube, the level of X-ray radiation emitted by other electronic tubes, in the distance from the shell of the equipment at a distance of 5 centimeters shall not exceed 20 millilunars/hour (5.16 × Coulomb/kg), which corresponds to 0.02 roentgens (rad), which will not be affected at all.