The method, spiral CT scanning, can find lung cancers when they are about as small around as a pea. Chest X-rays find lung cancers when they are about the size of a quarter.
The scanning method is so new that doctors are still learning about it, including whether it can help save lives. The first major papers on it were written in April and July, but patients are already lining up for the scan, and hospitals are offering to provide it.
Medical experts at a workshop in Gaithersburg, Maryland, on Tuesday said the new method could become so widely used that no one will question its effects.
They called for an immediate study, possibly involving tens of thousands of people.
"We need to convey to decision-makers that a study should be moved on as quickly as possible so that we can understand the benefits and risks of this technology," said Dr. Christine Berg of the National Cancer Institute.
Dr. Claudia Henschke of Cornell University, who has directed a study of smokers and ex-smokers, estimated the new method of spotting tumors could allow up to 80 percent of lung cancer patients to survive at least five years.
Only 15 percent currently live that long.