hundreds of times more powerful, are incredible diagnostic tools. but each time a child gets a scan, it comes with a dose of radiation. and radiation, any radiation, means a higher risk of cancer. that's what the fda is warning about. one study finding that the number of ct scans in children has jumped 500% since 1995. to 1.65 million. and one-third of all ct scans aren't needed. one example? concussions. where ct scans just aren't useful in most cases. radiation is especially dangerous for children because their bodies are developing, and they have so many years ahead of them for cancers to grow. >> when we do a study, we want to put it on the pediatric imaging parameter. >> so this little button here? >> yes. >> reporter: the fda called on doctors to give children a fraction of the dose an adult gets. and on manufacturers to make that easier. i asked the fda, what took so long? >> standards and research need to reach a certain level, and so we believe that there's now a body of clinical evidence that supports our guidance to manufacturers. >> reporter: parents, you should