Since Roentgen’s discovery of X-rays over 100 years ago, X-rays have served mankind in the diagnosis and treatment of disease with the physician’s alternative vision of being able to penetrate the surface and see changes in the internal structure of the body. Over the past 100 years, X-ray equipment has changed dramatically, from the simplest X-ray devices to digital computerized equipment, and 64- and 256-layer CT systems. As people pay more attention to health, as people’s living standards improve, and as advanced X-ray equipment becomes more and more popular, the number of people receiving X-ray examinations will gradually increase, and according to the data, at least 2/3 of Beijingers receive X-ray exposure for diagnostic examinations every year. Although X-ray equipment is changing rapidly, the basic principle is still the X-ray discovered by Mr. Roentgen more than 100 years ago. x-ray is a very short wavelength, invisible to the naked eye electromagnetic waves, its wavelength in the 0.006-500A (Å) range, it has a strong penetrating ability. A certain dose of X-rays through ionizing radiation, biological cells, especially proliferating cells, can cause cell inhibition, damage, and even necrosis. After being exposed to x-rays, the human body may react differently depending on its sensitivity to x-rays. The more proliferative the cells are, the more sensitive they are to x-rays, and this effect has been fully applied in radiotherapy for tumors. Due to the nature of X-rays, there is no denying that they are harmful to normal human tissues. According to the standard set by the International Commission on Radiological Protection, the total radiation risk is 0.0165 / sievert, which means that for every sievert (1 sievert = 1000 mSv) of radiation dose received by the body, the chance of cancer increases by 0.0165. By this reckoning, a patient with a broken rib will have an increased risk of about 3.8 parts per million. For other medical examinations, a general X-ray of the extremities will receive a radiation dose of 0.01 mSv, the abdomen 0.54 mSv, the pelvis 0.66 mSv, the lumbar spine 1.4 mSv, and the upper gastrointestinal tract 2.55 mSv. By this reckoning, the risk of cancer in healthy people due to medical examinations is between 1 in 10 million and 1 in 100,000. Based on the results of the International Commission on Radiation Protection (ICRP) study, it is estimated that about 350 people per year in Beijing may have cancer, leukemia or other hereditary diseases induced by X-ray exposure. Let’s take the most common chest examination as an example. ICRP Publication No. 44 of ’84 determined the maximum single dose of radiation received by human organs to be 7.5 Gorey, above which it is easy to get radioactive pneumonia. And the current X-ray examination, how big is its dose? According to the Chinese Medical University Department of Preventive Medicine Jia Mingxuan measured the dose of the lungs in the orthopantomograph of the chest is only 0.38 mGy, a difference of 20,000 times. The difference between the other most affected parts of the skin is also more than 1000 times. Therefore, an ordinary X-ray examination is not very harmful to the human body and there is no need to worry too much about it. CT is also an X-ray imaging device and also has X-ray radiation damage. Some articles report that the X-ray radiation dose from CT examinations is the same as that from an atomic bomb explosion, but some studies in the literature concluded that the X-ray radiation dose from an abdominal CT examination is 1.5 times more than the radiation dose from a conventional X-ray abdominal examination (Radiology 2004;232:126-132.). A comparison of the average radiation dose of multilayer spiral CT volumetric scanning head, chest, and abdominal examinations with the reference radiation dose specified in Europe in a special study by the International Atomic Energy Agency showed that the average radiation dose of spiral CT volumetric scanning was lower than the European standard (Radiology 2006;240:828-834.). Radiologists and equipment manufacturers are also making a concerted effort to reduce the radiation dose from X-ray examinations. General radiography has evolved from the traditional sensitized screen film approach to computed radiography CR and digital radiography DR, which have been reported in the literature to reduce radiation dose by 30% (Radiology 2005;237:691-700.); CT has undergone such techniques as controlled bulb focus motion, radiographic collimation, patient presetting, X-ray filtering, automatic adjustment of the bulb tube current, projection-adapted reconstruction filtering, and computer-simulated dose reduction software have also resulted in varying degrees (20-60%) of radiation dose reduction for CT examinations (Radiology 2004;230:619-628.). In summary, X-ray examinations do damage the human body, but the harm caused is a result of many factors, and whether pathological changes occur varies from person to person, otherwise X-ray examinations could not have experienced more than 100 years of development and still have an irreplaceable role in the diagnosis and treatment of human diseases. Personally, I believe that whether or not the radiation from X-rays causes irreversible damage is related to the radiation dose, the time interval between examinations, the individual’s sensitivity to radiation, the quality of the equipment used, and the type of examination, and that X-rays do not necessarily cause damage. The key is to avoid misuse of X-ray examinations, to avoid using substandard or outdated equipment, and to pay attention to radiation protection during examinations. In addition, the doctor should help the patient to understand the effect of the chosen X-ray examination on the patient’s condition and what problems can be solved, so as to relieve the patient’s worries; for the patient to analyze the radiation dose of the X-ray examination he or she receives in conjunction with the doctor’s introduction and the importance of the disease to be solved, if the disease requires the radiation of the X-ray examination to help the existing disease, I think If the disease requires that the radiation must be received in order to help the existing disease, I believe that the existing disease must be treated first. That would be more than worth the cost. In short, X-ray examinations have advantages and disadvantages, reasonable use, self-protection, then the advantages outweigh the disadvantages. Otherwise, the disadvantages outweigh the benefits. This requires mutual understanding and trust between doctors and patients, and the joint use of “harmful” X-ray examination.