Florida ? A CT scan — a kind of super X-ray — provides a faster, cheaper way to diagnose a heart attack when someone goes to the emergency room with chest pains, a new study suggests.

About 6 million people each year go to hospitals with chest pain, but only a small fraction are truly having a heart attack. CT scans are increasingly used to diagnose problems because they give a deep, detailed view inside the body. But they put out a lot of radiation, which may raise a person’s chances of developing cancer.

Whether these scans are worth that risk is unknown. The new study suggests that for ruling out heart attacks in the emergency room, they just might be.