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Understanding CT Scans and Radiation Exposure

Measure Scan Benefits Against Too Much Radiation

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Updated March 27, 2013

Few would disagree that Computed Tomography (CT, pronounced "cat") scanners are diagnostic dream machines. Doctors can see the inside of a patient - his or her organs and systems, with remarkable clarity. CT scans produce three-dimensional images that allow the doctor to see what's right, what's wrong, and what needs to be fixed, or left alone.

Doctors frequently order CT scans when they want to diagnose us or test our progress during treatment. In the perfect world it would be that simple, like taking a snapshot or watching a video.

But real danger can result from over use of CT scans. Smart patients understand the dangers, and therefore know what questions to ask when a doctor recommends a CT scan.

Why Should I Question Whether or Not to Get a CT Scan?

CT scans use radiation to create their images. Depending on what part of the body is being scanned, and the calibration of the scanner, we can be easily exposed to too much radiation. In some cases, the amount of radiation exposure can be 500 times that of an x-ray. That puts our health in danger in a variety of ways including possible damage to our DNA, and development of cancer over time.

There are many dangers inherent in any form of radiation exposure, so that's a start: understanding the danger of radiation exposure in a medical setting.

Please note, too, that because they are more sensitive to radiation, the danger for children getting CT scans can be even higher.

Doesn't the Doctor Know When I Need a CT scan Instead of Some Other Test?

Doctors order scans for many reasons. Unfortunately those reasons may be more important to them than they are to us. Here's why:

When CT scanning machines were first introduced in the early 1970s, they were very expensive and weren't found in many locations. Today their cost has come way down and scanners are often used as profit centers. It is much easier for a doctor's office, or hospital, or even a walk-in clinic or store front to buy them, order scans and charge very high prices for offering the service. While it seems "convenient" for us patients, the intent is too often more about making money from the service.

Because most of us patients don't understand the dangers, we agree to being scanned, and even when insurance doesn't reimburse for them, some of us pay from our pockets.

Further, many doctors make their recommendations to hedge against possible liability problems later. They will order tests, not because we necessarily need the test, but because they don't want anyone questioning their conclusions in the future.

Are CT Scans Always Dangerous?

Yes - and no.

Exposure to too much radiation is always dangerous, and too much exposure is a potential risk with a CT scan. However, when weighed against the diagnostic benefits of a CT scan, that exposure may be less dangerous than the alternative; that is - not getting the answers you need when a CT scan might so readily provide them. This is true for both adults and children.

Unless you are getting a whole body CT scan, then some parts of your body can be protected from the radiation through use of a lead apron or shield. The lead blocks the dangerous rays.

If you are pregnant, or the possibility exists, or if you are breast feeding, there may be a higher level of danger for your baby. Make sure you and your doctor discuss your pregnancy status prior to any exposure to radiation.

How Can I Be Sure I Really Need that CT Scan My Doctor Has Ordered?

The answer is to gauge the need for each CT scan as it is ordered. Here are five questions you can ask your doctor if he or she orders a CT scan for you. They will help you determine whether having a CT scan is the right approach for you at the time it is being ordered.

Are There Other Radiation Use Scans or Tests I should Ask About Too?

Any test that uses radiation to determine results is of concern, but they are used far less frequently for most patients and therefore don't raise the same red flags.

DEXA scans, mammograms, X-rays (including dental) and other imaging tests use radiation. If your doctor owns the equipment (or may have an ownership stake in the equipment), and you feel he or she is suggesting these tests more frequently than feels right to you, then you'll want to be sure to ask these same questions. Trust your intuition on that point.

In the Future:

The FDA has developed a plan to help patients better track their radiation exposure over time. Even when that becomes reality, smart patients will continue to ask questions to ask about getting CT scans and and other radiation-based tests, too.

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