U.S. researchers say using a three-dimensional computer scan instead of x-rays to look for tumors in smokers cuts the lung cancer death rate by 20 percent.
In the study, sponsored by the U.S. National Cancer Institute, 53,000 former and current smokers were given either a regular x-ray or the three-dimensional scan, called a spiral CT scan.
Doctors observing the death rate of the subjects found a 20 percent reduction in lung cancer fatalities because tumors were more easily spotted.
The spiral CT scan takes pictures all sides of the lung. It is the same technology used to diagnose breast and colon cancer.
But the researchers say it is too early to recommend the scan for people who have never smoked. They also say the scan could give false positive reports or increase the risk other cancers from radiation.
The doctors also stress that no one should use the breakthrough as an excuse to start smoking cigarettes or for refusing to quit.