If children have brain CT, it may cause the following hazards: 1. cause cell carcinogenesis, because the radiation of brain CT is relatively large, if children are given brain CT examination for a short period of time several times, it will often cause cell carcinogenesis in children’s body, resulting in the occurrence of tumors. 2. cause immune deficiency, children who have brain CT will often cause a decrease in the level of white blood cells, after children’s white blood cell count decreases, it will cause immune function damage. This can cause damage to immune function, which can lead to recurrent cough, fever and a series of other symptoms. Therefore, children should be cautious when undergoing brain CT, weighing the pros and cons, and try not to do it as much as possible, and strictly control the indications when doing it.