The FDA is urging manufacturers to design new scanners with children's safety in mind.
Too much exposure may increase the risk of cancer later in life.
The FDA is also calling on parents to do more to cut down on unnecessary radiation.
The agency advises parents to ask why a test is needed and whether there are radiation-free alternatives.
Doctors say radiation imaging is a necessary tool as long as it's not overused.
The FDA is also working on new safety training materials for doctors and technicians who administer x-rays and scans to children.