Americans are being exposed to higher doses of radiation than ever before because of the increase in medical testing, a new report from the National Council on Radiation Protection and Measurements found.

It discovered Americans are exposed to seven times more radiation today than we were in 1980. Nearly half of total radiation exposure comes from medical procedures, with nearly a quarter of all radiation exposure comes from tests such as Computed Tomography (CT) -- also known as CAT -- scans, according to the study. Physicians performed 72 million CT scans in the U.S. in 2008, compared to about 3 million in the 80s.

NCRP researchers are concerned that many tests are unnecessary and that the doctors who prescribe them do not fully appreciate the increase in cancer risk that comes from having repeated scans. For example, one 64-slice CT scan of the heart is equivalent to about 600 chest X-rays.

But the tests can also be life-saving. When 15-year-old Ashley Karavolos tripped at school and hit her head a CT scan revealed an existing aneurysm. It was a lucky break, according to her mother, Pamela Skochinski.

"The aneurysm was in such a spot and was so big that if it burst, she would have bled out within twenty seconds and died," Skochinski said. They family likely would not have learned about the aneurysm until it was too late.

But even the small doses of radiation from CT scans can increase the risk of cancer, according to a study of the survivors of the 1945 atomic bombings in Japan. It found that even those exposed to low doses of radiation -- about the equivalent of two or three CT scans -- had roughly a 7-percent increased risk of cancer.

But doctors insist patients shouldn't put scans off because they fear radiation. "CT scans do give off some radiation. But no one is having a CT scan everyday, and the answers it can get is the worth the risk-- in double," according to Dr. Douglas DeCorato, of East River Imaging in New York.

Washington Hospital Center's Dr. James Jelinek adds, "If there's no reason to get an X-ray, there's no reason to get a CT scan, you absolutely should not."

But Dr. Jelinek warns that the benefits of such a scan outweigh the risks when needed. Doctors point to high-profile cases -- like Meet the Press moderator Tim Russert's death last year -- saying a simple heart scan could have saved his life, and countless others each year. 

But researchers worry some doctors are too quick to rely on radiological tests out of fear they may get sued.

"This is particularly true in the emergency room setting," said Dr. Stephen Amis, chairman of the radiology department at Montefiore Medical Center in Bronx, N.Y. "They don't want to make a mistake."

Dr. Amis also fears some doctors may order scans because they benefit financially" "If your doctors orders a CT scan, and he has the machine in the office right down the hall, I think it's worth asking, 'Do I really need the scan?'"

Dr. Jelinek adds, "Clearly if they own [the machine], if they're gonna get 85 percent of the bill, they're making money for every time one of their patients gets scanned."

Patients can help protect themselves by asking whether radiological testing is truly necessary, and if there might be another option that could provide the same information with less radiation.

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