How much radiation does the X-ray have?

Although X-ray equipment is changing with each passing day, its basic principle is still X-ray discovered by Mr. Roentgen more than 0/00 years ago. X-ray is an electromagnetic wave with a short wavelength, which is invisible to the naked eye. Its wavelength is in the range of 0.006-500 angstrom, and it has strong penetration ability. A certain dose of X-ray can inhibit, damage or even necrosis biological cells, especially cells with strong proliferative ability, through ionizing radiation. After the human body is irradiated by X-rays, different reactions may occur according to its sensitivity to X-rays. The higher the cell proliferation, the more sensitive it is to X-rays, which have been fully applied to radiotherapy of tumors. Because of the characteristics of X-ray, it is undeniable that it is harmful to normal tissues of human body. 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.

Let's take the most common chest examination as an example. The maximum acceptable dose of human organs measured in the publication No.44 of the International Commission on Radiological Protection 1984 is 7.5 Gy, and radiation pneumonia is easy to occur if it exceeds this dose. And now the X-ray examination, how big is its dose? According to Jia, Department of Preventive Medicine, China Medical University, the lung dose was only 0.38 mGy when chest radiographs were taken, with a difference of 20,000 times. The skin difference of other parts with the greatest influence is also more than 1000 times.

CT is also an X-ray imaging equipment, and it also has X-ray radiation damage. Literature research shows that the X-ray radiation dose of abdominal CT examination is 65438 0.5 times higher than that of conventional X-ray abdominal examination (radiology 2004232:126-132.). In a special study of IAEA, the average radiation dose of multi-slice spiral CT volume scanning head, chest and abdomen was compared with the reference radiation dose stipulated in Europe. The results show that the average radiation dose of spiral CT volume scanning is lower than the European standard (Radiology 2006240:828-834.).

Radiologists and equipment manufacturers are also working together to reduce the radiation dose of X-ray examination. Ordinary X-ray examination has gradually developed from the traditional method of intensifying screen film to popularizing computer X-ray photography y Cr and digital X-ray photography y Dr, and there are reports that the radiation dose can be reduced by 30%(Radiology 2005；; 237:69 1-700.); CT also reduces the radiation dose of CT examination in different degrees (20-60%) by controlling the focus movement of the tube, ray collimation, patient preset, X-ray filtering, automatic adjustment of tube current, projection adaptation reconstruction filtering, computer simulation dose reduction software and other technologies (radiology 2004 230: 619-628.).

Therefore, an ordinary X-ray examination is harmless to the human body, so don't worry too much. However, if you receive too many X-rays unreasonably, it is still possible to induce cancer, leukemia or other genetic diseases due to exposure to X-rays. Whether the radiation of X-ray inspection causes irreversible damage is related to radiation dose, inspection interval, personal sensitivity to radiation, quality of equipment used and inspection type, but X-ray inspection does not necessarily cause damage. The key is to avoid the abuse of X-ray inspection, avoid using unqualified or backward equipment for inspection, and pay attention to radiation protection during inspection.