The society is releasing new guidelines for annual CT lung scans but they are only recommended for people aged 55 to 74 who have smoked a pack of cigarettes a day for 30 years.
Or two packs a day for 15 years.
Research shows screening these people can cut the risk of dying of lung cancer by 20 percent.
Whether screening would help others is not known, so scans are not recommended for them.
The guidelines say patients considering screening should have a frank talk about the risks and benefits with their doctors.