ORLANDO, 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.