Ask the doctor: Should I worry about x-rays?

Q. I always worry about cancer risks when I have -x-rays or airport screenings. Am I overreacting?

A. We use a lot of x-rays in medicine and in other places (like airports). Too much radiation exposure over time definitely can have adverse effects on health. So you're right to be careful, and to ask if you really need a test that involves radiation when your doctor orders one. How can you assess how much radiation you're getting, and how much is too much?