How harmful CT is for newborns needs to be decided according to the number of times the child has had CT done. First of all, it is a negligible hazard. If a newborn does CT once in a while, the amount of radiation in this case is very small, and parents need not worry too much about it. Because the relative time for children to do CT is relatively short, a few minutes can be completed, where the amount of radiation is very limited. Secondly, if a child has CT done several times in a short period of time, the amount of radiation in this case is very high, because the number of times is relatively large and can play a role in accumulation, which may have an impact on the child, such as inhibiting the hematopoiesis of the bone marrow, etc.