Think of all the times you've allowed a dentist to X-ray your teeth.

Reach a certain age, and it doesn't take long before you lose count completely. Some people get zapped every year or two, simply because the dentist tells them to.

But a new study shows what's really at stake here: People who get X-rayed the most have the highest risk of thyroid cancer.

British researchers looking into the rising rates of this unusual condition compared 313 thyroid cancer patients in Kuwait to a similar number of people who didn't have the disease.

Like Britain, Kuwait is experiencing its own thyroid cancer boom. Kuwait also offers free dental care, so those X-rays are there for the taking--and they appear to be taking a toll. The researchers found that patients who've received 10 or more dental X-rays have 5.4 times the thyroid cancer risk of those who've never been X-rayed by a dentist.

Those who've had between five and nine dental X-rays had quadruple the risk, and those who've had between one and four X-ray sessions had more than double the risk, according to the study in Acta Oncologica.

The researchers behind the new study are calling on dentists to stop routine X-rays and stop X-raying patients simply because it's their first office visit.

Good luck with that.

If you leave it up to your dentist, you'll get X-rayed every time you walk past his office. So don't rely on him-- rely on yourself, and not just when you visit the dentist, because he's not the only one trying to zap you.

Radiation-based testing, from dental X-rays to CT scans and everything in between, offer doctors so much more than a detailed view of your interior. They offer a quick and often unquestioned route to some of the easiest money in medicine.

As a result, Americans have become the most radioactive people on earth--we get half of all advanced medical procedures that involve radiation. On average, Americans now get six times more radiation than we did just a couple of decades ago, according to recent studies.

So anytime a doctor or dentist wants to zap you with a radioactive blast, ask him why. Ask about your alternatives. And, more importantly, ask what will happen if you don't sit down for that test.

Sometimes, these tests are necessary--but in most cases, they're not... and if your doctor's answers sound a little too much like "I just want to check" or if he uses the word "precautionary," think twice before you put on that lead apron.