拍摄一张X光胸片，当射线在检查区域曝光时其曝光率约为160毫西弗特（计量辐射度的单位）／小时，约为0．045毫西弗特／秒。以胸部肋骨骨折为例，拍摄一张胸片大约需0．5秒，因此接受一次胸部X射线检查，患者要承受约为0．023毫西弗特的辐射量。按照六次X射线检查，一个肋骨骨折的患者前后总共要承受0．138毫西弗特的辐射剂量。  根据国际放射防护委员会制定的标准，辐射总危险度为0．0165／西弗特，也就是说，身体每接受一西弗特（1西弗特＝1000毫西弗特）的辐射剂量，就会增加0．0165的致癌几率。以此推算，一个肋骨骨折病人将增加约为千万分之三点八的危险。 而对其他医学检查来说，一般四肢做一次X光检查要接受的辐射量为0．01毫西弗特，腹部为0．54毫西弗特，骨盆为0．66毫西弗特，腰椎为1．4毫西弗特，上消化道为2．55毫西弗特。以此推算，因为医学检查导致健康人群患癌的风险在千万分之一到十万分之一之间。 孕妇儿童在辐射高危人群之列 尽管大部分的医院在对普通病人进行X光照射的时候并没有采取任何防护措施，但是对于孕妇，还是有所顾忌的，对其腹部进行遮盖。于医生建议孕妇应该尽量避免此类检查，尤其是怀孕头三个月的孕妇。因为此时是胎儿重要器官形成的关键时期，X光可能使这些尚未发育定型的细胞组织产生突变，胎儿先天畸形的发生率也会增高。还有研究表明，新生儿如果因头部受损伤做CT检查，对以后的学习能力、逻辑推理能力有一定影响，而对空间识别能力则没什么影响。 除了孕妇之外，儿童也是辐射损伤的高危人群之一。
A picture of a X ray film, when ray exposure in the inspection area the exposure rate is about 160 millisieverts (measurement radiation units) per hour, about 0.045 millisieverts per second. The chest rib fracture as an example, a picture of a chest takes about 0.5 seconds, so take a chest X ray examination, the patient should bear the amount of radiation is about 0.023 millisieverts. According to the six X ray radiation dose and a rib fracture were subjected to a total of 0.138 millisieverts per. According to the standards set by the International Radiation Protection Committee, the total risk of radiation is 0.0165 / Siefert, that is to say, the radiation dose of Siefert (1 Siefert = 1000 milli Siefert) will increase the risk of cancer by 0.0165. As a result, a rib fracture will be increased by about three point eight per cent of the risk. But for other medical examination, general limbs do a X ray radiation to accept 0.01 millisieverts, abdomen 0.54 millisieverts, pelvis 0.66 millisieverts, lumbar 1.4 millisieverts, upper digestive tract of 2.55 millisieverts. As a result of the medical examination, the risk of cancer in the healthy population is between 10 million and 1/100000. Pregnant women in the high-risk group of radiation, although most hospitals did not take any protective measures when they were irradiated by ordinary X patients, but for pregnant women, there were still some scruples to cover their abdomen. Doctors suggest that pregnant women should try to avoid such tests, especially pregnant women who have been pregnant for the first three months. Because this is the critical period for the formation of important organs of fetus. X light may cause mutations in these undeveloped cell tissues, and the incidence of fetal congenital malformations will also increase. Studies also show that if a newborn is injured by head, making CT examination has certain influence on later learning ability and logical reasoning ability, but has little effect on spatial recognition ability. In addition to pregnant women, children are also one of the high-risk groups of radiation injury.