The common test with an uncommon risk

They say ignorance is bliss, but that's not true at all. Ignorance is actually a proven carcinogen.

Millions of people have no idea when they are getting radiation exposure -- and many millions more may know when they're exposed, but don't believe they can get cancer from it. And that lack of knowledge is responsible for thousands of cases of cancer every year.

Right now, 72 million people get CT scans annually. These tests use massive levels of radiation -- more than 100 times the radiation exposure of a standard chest X-ray. And in some cases, between 500 and 1,000 times the radiation of that chest X-ray.

Can that cause cancer? You bet it can.

But according to one new survey, a full third of patients about to get a CT scan have no idea that it involves any radiation at all. And while the rest are aware of the radiation exposure, they're clearly not afraid -- because just 5 percent believe CT scans can cause cancer.

Extrapolate the numbers, and of the 72 million CT scan patients, 24 million have no idea they're getting radiation exposure -- and 68.5 million don't believe they can get cancer from it.

But as one recent study found, we can expect 29,000 new cases of cancer down the road just from the 72 million CT scans performed in a single year.

How many of those 72 million would have opted out if they had known that? I'd like to think plenty -- especially in cases where there were other options. But since they weren't informed, they didn't opt out.

And since they didn't opt out, they'll get cancer... ignorance-driven cancer.

I don't blame them. I blame their doctors -- because they do know the risks, and they're clearly not communicating them to their patients.

But now you know, too -- and while I won't say never get a CT scan since there are times when it can save your life, I will say that many of the 72 million scans delivered each year are unnecessary.

So always ask your doctor why you're getting scanned and what the risks are -- and more importantly, ask him if you have other options.