The nuclear safety issue caused by the Fukushima nuclear power plant in Japan has recently become the focus of attention, and radiation protection is gradually coming into the limelight. Many patients ask their doctors to provide radiation-protective clothing when they go to the hospital radiology department for examinations. X-ray and CT are the most common imaging methods, and we do not need to worry about the harm of radiation on the human body. Now analyze this patient misconceptions are as follows: Myth 1: radiation is harmful to the human body, insist on being sick also do not take a film chest ortho-imaging lung exposure dose of 0.12mSv, about 1/20000 of the single maximum accepted dose that causes human injury, so that an ordinary X-ray radiography, the degree of harm to people is not much, do not need to worry too much. Myth 2: Not metal is not an obstacle With the increasing level of public culture and medical knowledge, people gradually recognize that metal and high-density items will hinder the penetration of X-rays, such as metal buttons, necklaces, jade pendants, bras, etc., patients will generally cooperate with doctors to remove them, but similar knee pads, plasters, quilts and clothing on the paint pattern, etc., will affect the penetration of X-rays, even in the X-ray film left images, thus making it difficult for doctors to diagnose. Misconception three: the two sides of the body to take the camera we usually use if the left side of the face can not see the right side. But X-rays are different, it has the penetrating nature, see the internal substance. Therefore, if you are shooting limb bones and spine is a side on it. This is not like the lungs are divided into the left and right lungs, so once which side has a problem, you have to which side against the film, the purpose is to make the lesion side can be more clearly displayed on the X-ray film to reduce the magnification. Myth 4: The effect of standing and lying down is the same. It is a misconception that the effect of standing and lying down is not different. Take the chest photo for example, the purpose of standing can make the heart shadow natural under the effect of gravity, in the large inhalation can make the lungs expand, the front chest against the film can reduce the blurring of the heart, reduce the magnification of the heart, and because of the increase in the distance of the projection of both sides of the scapula projection in the lung field outside and reduce the magnification of the chest. This effect is not achieved when shooting lying down. Therefore, the patient should insist on standing, even with the support of friends and relatives, or sitting. Of course, in life-threatening situations will have to be flexible.