Fifty-five year old Paulette Caballero's father died of a heart attack. So when she had an abnormal cardiogram, her doctor wanted to know if she was headed in the same direction, CBS News medical correspondent Jon LaPook reports.
"My cardiologist recommended I do a CT scan," Caballero said.
The cardiac CT scan, which costs about $800, gives doctors clear 3D images of the coronary arteries without having to do an invasive angiography.
But the test exposes patients to potentially harmful radiation. Exactly how much has been unclear, prompting an international study with a surprising result.
"We found that the scanner output varied approximately six-fold between the different imaging sites," said the study's author, Dr. Thomas Gerber.
Patients can be getting radiation equal to 600 chest x-rays.
One reason for the wide variation: not every site is taking steps to reduce the radiation dose.
What's the lesson? "Educate the medical community what they can and must do to decrease the radiation dose from the tests they perform," Gerber said.
What are the radiation risks of this test?
"The primary radiation risks are the possibility of developing lung cancer or breast cancer at some point subsequent to the test," said Dr. Andrew Einstein of Columbia University Medical Center.
The government doesn't regulate the amount of radiation a patient gets during a cardiac CT scan, and the dose can vary widely.
It's up to a referring doctor to estimate what dose you'll be getting,
With CT scans, accounting for almost half of medical radiation, the American Heart Association Monday cautioned physicians to carefully balance the risks and benefits.
"Every CT we do in a patient that has very low risk and no symptoms, that's probably one too many," Gerber said.
Caballero's heart scan was normal.
"Everything was clear, and I'm happy about that," Caballero said.
She's also happy that her scan was low-dose - a goal yet to be realized everywhre.