Whether outpatients or hospitalized surgical patients, they often ask me always so photo sub, will it be too much radiation? Generally I will answer, these tests are not a big problem, but I think a lot of people may still feel uneasy in their hearts, which is human nature. Then we are here to clarify a few basic concepts, and then calculate the orthopedic examination radiation will not be too large? 1, what is radiation? What we call ionizing radiation refers to direct or indirect ionizing particles or a mixture of the two composed of radiation. Radiation that can make the affected material ionization phenomenon, that is, electromagnetic radiation with a wavelength of less than 100nm. 2.What are the orthopedic related examinations that have radiation? X-ray, CT examination, bone density examination has ionizing radiation, MRI and ultrasound do not have ionizing radiation, where the following signs are posted at the entrance of the examination room, you need to pay attention to this examination has radiation. 3. What dose of radiation will cause harm to the human body? Measure the unit of ionizing radiation is millisieverts (mSv), people receive about 3mSv of radiation in nature each year, increasing the risk of cancer annual dose is 100mSv, every increase of 10mSv, the chance of dying of cancer increased by 1/2000, short-term exposure to radiation doses greater than 500mSv, there will be vomiting, diarrhea, hair loss, skin damage, bleeding, fuzzy consciousness, or even death and other Risks. 4, orthopedic examination radiation comparison It can be seen that the routine orthopedic examination generally does not exceed the safe radiation dose, in addition to the spine CT examination is relatively large amount of radiation, the other examinations are basically safer. Of course, the principle of any orthopedic examination with radiation is still to minimize, but if you need to do, even if you have to do X-ray and CT examination several times a year, basically they are all in the safe and controllable range.