How much radiation have you been exposed to today?

Americans are being zapped with potentially harmful rays from diagnostic tests with alarming regularity – alarming because, in many cases, you never need to take that risk in the first place.

A new report finds that more than half of all abdominal CT scans are unnecessary.

What makes this news all the more frightening is that these scans are far more powerful than traditional X-rays. In fact, the report presented at a meeting of the Radiological Society of North America found that the average CT scan uses enough radiation to power 113 X-rays – with some people getting far more, equivalent to 500 or even 1,000 X- rays.

I wonder how many of these patients knew what they were being hit with – or the odds that their test wasn't even necessary in the first place.

I'm guessing many didn't – and probably wouldn't have signed up for an abdominal CT scan if they did.

Here's something else I'll bet they didn't know: The researchers in this study concluded that abdominal CT scans lead to around 23,000 radiation-induced cancers every year.

But now you know. And if your doctor starts ordering up these tests, start asking some questions first – no matter what type of scan he's trying to perform.

Sadly, it's up to you to distinguish a doctor trying to help you from a doctor looking to make a few extra dollars off testing – to separate the scans from the scams.

Radiation exposure is practically an epidemic in this country – while this frightening new report looked only at abdominal CT scans, another recent study found that up to 4 million Americans are exposed to high levels of radiation every year. That's more people than in the entire city of Los Angeles.

Yet another recent report found that Americans today are typically hit with seven times the amount of radiation from diagnostic tests than we were 30 years ago.

I'm sure some of that is due to more powerful testing becoming more widely available. But I'm just as sure that in many cases, people are being forced to repeat tests for multiple doctors who aren't talking to each other (even if you might assume they are), and doctors who just order up these tests willy-nilly to help pay the bills.

For you, that means being more vigilant, more proactive and asking more questions – like why your doc thinks you may need a test, what he thinks the test might reveal, what your alternatives are and what would happen if you didn't get that scan.

Also make sure that if you have multiple doctors, they're on the same page – if one doctor is convinced you need a diagnostic test, and you agree, then make sure your other doctors get the results so you can avoid duplicate tests later on.

Remember, if you don't stick up for yourself – no one else will.